third generation mobile system (3g): cdma2000

Mobile Evolution to 3G

١

Third Generation Mobile System (3G):

Cdma2000

1) INTRODUCR TION:

1.1) Market requirements and services for 3G mobile

radio system

2G are very successful world wide in providing services to users. But the

customer base increasing much faster than initially expected.

UMTS expecting around 400 million mobile subscribers world wide in year

2000, and about 1800 million subscribers in the year 2010,

However 2G are limited in maximum data rates, also high percentage of

mobile multimedia users will increase after year 2000.

UMTS also expected in 2010 that 60% of the traffic in Europe would be

created by mobile multimedia. A similar growth of mobile data traffic is

expects in worldwide.

Market requirements need more advanced services than current voice and low

data rate services.

Market requirements are classified in three different sections:


٢

Computer data Telecommunication audio- video content

Fig 1 Future service will range from low up to high user data rate (maximum 2Mbps

for IMT-2000/UMTS systems). The transmission of, for example, a large

presentation of a size of 16Mbps would need 8 second with a 2Mbps service

compared to current data transmission in GSM with 9.6Kbps, where 28

minutes would be necessary

UMTS

• Computer data • E-mail • Real time image transfer • Multimedia document transfer • Mobile computing

• Mobility • Video conferencing • GSM, ISDN service • Video telephony • Wide band data services

• Video on demand • Interactive video services • Electronic newspaper • Telescoping • Value-added internet services


٣

1.2) Technical requirement and radio environment

Mbps

M

Fig 2

These market requirements and services need results in international technical

requirement for ongoing definition of third generation mobile radio systems.

High data rates requirements are up to at least 144Kbps in vehicular up to

at least 384Kbps in outdoor to indoor, and up to 2Mbps indoor and

picocell environment.

Circuit-switched and packet-switched services for symmetric and

asymmetric need to be supported. Third generation systems will operates

in all radio environments. In addition, the ability for global roaming has

to be supported in the system design.

10

1.0

0.1

0.01

3G uniting FDD- and TDD-services

2G TDD: E.g. DECT, PHS

2G FDD: e.g. GSM, IS-136, IS-95 CDMA, PDC

Office or room Building stationary Pedestrian vehicular

Indoor Outdoor

Wire

less

term

inal


٤

1.3) Comparison between 2G &2.5G and 3G Aspects 2G 2.5G 3G

Frequency band They operates at multiple frequency bands, 800 MHz ,900 MHz (cellular band) and in 1.5GHz, 1.8GHz (PCS band)

The same as 2G Use of common global frequency band from 1885 to 2025 MHz and from 2110 to 2200 MHz

Roaming Generally limited to specific region due to the use of SIM, and UIM modules facilitating border roaming capability

The same as 2G Improved in global roaming due to the use of common global frequency.

Data services Good for voice , but limited in data application less than 32kbps

Good for voice. But improved in data services by using GPRS that can operates at 172kbps, EDGE that can operates a1t 384kbps

Perfect for voice, support many data services than 2G and 2.5G, from 144kbps in mobility till 2Mcps indoor

Digital modulation Use Gaussian minimum shift keying (GMSK) for GSM , and 64 array orthogonal modulation for IS-95

GPRS is the same like GSM, EDGE use 8 phase shift keying (8PSK)

Use quadrate phase

shift keying

(QPSK)


٥

Commonality for different operating environment

They are primary optimized for specific operating environment (e.g. vehicular & pedestrian and may assign for fixed wireless access (FWA)

The same as 2G A key objective is maximizing the commonality optimization of radio interference for multiple operating environment, (e.g. vehicular, pedestrian, office, FWA and satellite operation)

Quality of services (QOS)

Limited quality of services due to presence of blocking, limited capacity

Improved QOS compared to 2G but still didn’t meet the market requirement

Better QOS have 4 classes and differ for the type of data application used. Conversational class used for (e.g. voice call) and streaming class used for (e.g. video on demand) these two classes are used for delay sensitive application. Interactive class used for (e.g. e-mail and telnet) and background class used for (e.g. downloading) the last two types of QOS used for delay insensitive application.


٦

Type of switching

Use only circuit switching

Use packet and circuit switching

Use packet and circuit switching

1.4) 2G to 3G Evolution Associations 2G 2.5G 3G

3G harmonization Group Fig 3

As we saw from this flow chart that there is three systems for the second

generation. GSM from Europe and IS-136 from America that is working overlaid

on the old analog system AMPS, and the third one is IS-95 that is completely

digital. And the two main proposals those will path for the 3G

Is w-CDMA from Europe, and cdma2000 from America, which is multi-

carrier from IS-95? That will be explained later.

1.5) Standardizing comminute for 3G mobile International Mobile Telecommunications 2000 (IMT-2000), a representative

name for third generation (3G) mobile communication system, aims to provide

an effective solution for the next-generation mobile services.

ETSI GSM associatio T1 UWCC TIA CDG

GSM TDMA IS-136

IS-95

GPRS/EDGE 1XRTT HDR

W-CDMA UWC-136 Cdma2000

3GPP UWCC 3GPP2

Table 1


٧

Progressing from the previous two generations, the technologies for the (3G)

mobile system have been significantly improved in terms of system capacity,

voice quality, and ease of use.

3G systems are expected to offer better system capacity and higher data rate

transmission speed to support wireless Internet access and wire-less multimedia

services (including audio, video and images). To bridge 2G technologies to 3G

technologies. EDGE and G PRS were introduced; they are typically referred to as

2.5G technologies.

The initiation of 3G comes from manufactures, not operators. Work on 3G

started around 1992, when international telecommunication union (ITU) formed

task group (TG) 8/1 working on FPLMTS, which was later renamed IMT-2000 in

1996 or 1997. Work in TG 8/1 was accelerated in 1994, which involved

government agents, manufactures, and operators around the world. In 1996 NTT

and Ericsson initiated 3 g developments. In 1997, the U. S. Telecommunication

industry association (TIA) chose the CDMA technology for the 3G. European

telecommunication standards institute (ETSI) also selected the CDMA technology

for the 3G. In the same year, Wideband CDMA (W-CDMA), cdma2000, and 3G

time division duplexing (TDD) were developed by the universal mobile

telecommunication system (UMTS), TIA 45.5, and china /Europe, respectively.

The 3G technology supports 144kbps bandwidth, with high-speed movement (e.g.

in vehicles), 384kbps bandwidth with pedestrian (e.g. on campus), and 2Mbps for

stationary (e.g. in buildings). The services will include high- quality voice,

Internet / Intranet accesses, and multimedia.


٨

1.5.1) Paradigm Shifts in Third-Generation Systems

Wireless data transmission via mobile system offers tremendous opportunities for

technologists and entrepreneurs ensure to provide their services at the right place

and the right time.

The concepts of the third-generation systems introduce two paradigm

shifts:

1) The shift from voice centric traffic to data centric traffic

demands a packet-based infrastructure of the irrational circuit-

based infrastructure.

2) Data applications continue to evolve: As a result, advanced

application protocols and human interfaces become very crucial in

practical applications

3G wireless communications requires a very broadband spectrum and fast

data to support high-quality Internet access and multimedia services.

Bandwidth, however is always limited the next table lists the existing

spectrum used by the 2G systems and new sum

Allocated for 3G. According to the table, only 25 percent (155 MHz out

of 628 MHz) of the spectrum is newly created for the terrestrial 3G

usage.

Terrestrial spectrum allocation for 2G and 3G SPECTRUM BANDWIDTH SYSTEMS

800 MHz 50 MHz Amps, IS-95, IS-136

900 MHz 50 MHz GSM 900 1500 MHz 48 MHz Japan PDC 1700 MHz 60 MHz Korean PCS 1800 MHz 150 MHz GSM 1800 1900 MHz 120 MHz PCS 2100 MHz 155 MHz 3G

Table 2


٩

1.6) W-CDMA and cdma2000 The CDMA- based 3G standards selected from numerous proposals to

ITU have become the major stream for IMT-2000. In practical, W-

CDMA and cdma2000 are two major proposals for the third-

generation systems. Even though both systems are CDMA-based,

many distinguishing features can be identified, as listed in the next

table for one, W-CDMA uses dedicated time division multiplexing

(TDM) pilot signal, where by the channel estimation information is

collected from another signal stream. This approach reduces the

overall pilot power. In contrast, cdma2000 uses common code

division multiplexing (CDM) pilot, where by channel estimation

information can be collected by signal stream. W-CDMA does not

need base station timing synchronization, whereas base station timing

synchronization in cdma2000 can provide decreased latency and

reduced chance of dropping calls during soft handoff.

Comparison between W-CDMA and cdma2000 TECHNOLOGY W-CDMA CDMA2000

Chip rate 4.096 then become 3.84Mcps

3.6864Mcps

Forward link pilot structure

Dedicated pilot with TDM

Common pilot with CDM

Base station timing synchronization

Asynchronous Synchronous using GPS receivers

Forward link modes A multi-carrier mode capable of overlay onto IS-95 carriers

17.8/22.4 for self evolution

36.7/29 for self evolution

Spectrum efficiency for forward link /reverse link measured by Erlang/MHz/cell

18.4/22 for chines evolution

26.4/27.2 for chines evolution


١٠

Table 9.3 The impact of system normalized spectrum efficiency in

Erlang/MHz/cell for voice services in a vehicular environment was

shown in the previous table shown

* Higher Erlang/MHz/Omni cell equates to greater efficiency

9.1.7) Harmonization

Since both W-CDMA and cdma2000 have been simultaneously adapted

for the 3G standard, harmonization of these two systems becomes

necessary to make IMT-2000 deployment successful. Two crucial

events have significantly enhanced harmonization of W-CDMA and

cdma2000. The first is Ericsson’s acquisition of Qualcomm’s

infrastructure division, which resolved contention of intellectual

property rights (IPR) between the two companies. The second event is

the adoption of operator’s harmonization group (OHG)

recommendations by all major players. OHG has drawn its

harmonization framework heavily from W-CDMA and cdma2000. The

goals are:

• To provide the foundation for accelerated growth in the 3G

millennium

• To create a single integrated 3G CDMA specification and

process from the separate W-CDMA and cdma2000

proposals being developed by the third generation partnership

project (3GPP) and (3GPP2).


١١

OHG’s efforts have result in:

• A direct spread mode with 3.84Mcps for new frequency bands,

and multi-carrier mode with 3.6864Mcps for operation

overlaid to IS-95 signals.

• A CDM pilot added to the direct spread mode

• A harmonized solution for SCDMA (a TDD mode Third

Generation system proposed by china)

The manufacturing community has agreed to cross-license intellectual

property on fair, reasonable and nondiscriminatory terms for 3G

development. However, due to political reasons, the two chip rates and

the two synchronous and asynchronous systems are likely to coexist.

Furthermore, the equipment

Supplies have their own concerns on current markets and wireless

technologies. Thus it is likely that the 3G harmonization cannot be

achieved at the physical layer. Instead more efforts will be spent on

interoperability oh higher layer protocols for W-CDMA and cdma2000,

which results in higher costs with degraded performance.

The activities of the 3G development so far have focused on physical

and MAC layers. Three radio modules (modes) were selected for 3G CDMA radio access:

MODE FDD(DS) FDD(MC) TDD Chip rate 3.84MCps 3.6864MCps 3.84MCps Common pilot CDM CDM To be determined Dedicated pilot TDM CDM To be determined Base station synchronization

Asynchronous/ synchronous

Synchronous as cdma2000

To be determined

Table 4


١٢

• Direct sequencing (DS) frequency division duplex (FDD) mode 1

• Multi-carrier (MC) FDD mode 2

• Time division duplex (TDD) mode

The direct sequence mode will be based on the W-CDMA proposal, and

the MC mode will be based on the cdma2000 proposal. The TDD mode

is an unpaired band solution to better facilitate indoors cordless

communications; it has been studied in china. This mode provides

asymmetric data services and is a potential low-cost solution.

1.8) Quality of services in 3G

From the viewpoint of end users, QOS should be provided on the end-

to-end basis. QOS attributes should be general but simple, and their

number should be small. From the point of view of the network, QOS

will be defined with a set of parameters blocking probability, voice

quality, data application, and time of service...Etc.

The 3G QOS control mechanism should:

1) Efficiently utilize resources based on the ability to dynamically

change QOS parameters during a communication session

2) Interwork with current QOS schemes

3) Present end-to-end QOS to the users with appropriate mapping.

The end-to-end service on the application level uses the bearer services

of the underlying networks, partitioned into three segments.


١٣

1) The local bearer service provides a connection between terminal

equipment (TE) and mobile equipment (ME). A TE can be a PC or PAD

connected to the 3G network through a MT.

2) The 3G-bearer service provides 3G QOS.

3) An external bearer service provides the connection to the other party

in the call. This bearer may utilize several network services (e.g. another

3G bearer service) connecting to the other party of the communication

session

The QOS classes defined for mobile networks are very different from

fixed networks due to the restrictions and limitations of the air interface.

Based on delay sensitivity,

Four QOS classes have been defined for 3G traffic: conversational,

streaming, interactive, and background.

Conversational class is defined for the most delay-sensitive applications

(traditional voice calls), and the transfer delay is strictly limited.

Steaming class is defined for one-way real time video/audio (e.g. video-

on-demand).

Both conversational and streaming classes will need better channel

coding and retransmission to reduce the error rate in order to meet the

required QOS.

Interactive and background classes and defined for delay-insensitive

services. The interactive class is used for application such as Telnet,

interactive e-mail, and web browsing.

The background class is defined for activities such as ftp or background

downloading of e-mails.

Among traffic classes just listed, the conversational class is most delay-

sensitive, and the background class is the most delay-insensitive


١٤

2) Reverse Link

In CDMA 2000 we have seven different radio configurations, to accommodate

different requirements of users; here we summarize these radio configurations

Radio Configuration Characteristics for the Reverse CDMA Channel Radio

Config

Associated

Spreading

Rate

Data Rates, Forward Error Correction,

and General Characteristics

1 1 1200, 2400, 4800, and 9600 bps data rates with R = 1/3,

64-ary orthogonal modulation

2 1 1800, 3600, 7200, and 14400 bps data rates with

R = 1/2, 64-ary orthogonal modulation

3 1

1500, 2700, 4800, 9600, 19200, 38400, 76800, and

153600 bps with R = 1/4, 307200 bps data rate with

R = 1/2, BPSK modulation with a pilot

4 1 1800, 3600, 7200, 14400, 28800, 57600, 115200, and

230400 with R = 1/4, BPSK modulation with a pilot


١٥

5 3

1500, 2700, 4800, 9600, 19200, 38400, 76800, and

153600 bps with R = 1/4, 307200 and 614400 bps data

rate with R = 1/3, BPSK modulation with a pilot

6 3

1800, 3600, 7200, 14400, 28800, 57600, 115200,

230400, and 460800 bps with R = 1/4, 1036800 bps data

rate with R = ½, BPSK modulation with a pilot

For Radio Configurations 3 through 6, the Reverse Dedicated Control Channel and

Reverse Fundamental Channel also allow a 9600 bps, 5 ms format.

Table 5

Reverse CDMA Channels Received at the Base Station

REVERSE CDMA CHANNEL(1.25 MHz or 5 MHz channel received by base station)

AccessChannel

ReverseTraffic

Channel(RC 1 or 2)

EnhancedAccess

Channel

ReverseCommonControlChannel

ReverseDedicatedChannel

(RC 3 to 6)

ReverseFundamental

Channel

ReversePilot Channel



0 to 7 ReverseSupplementalCode Channels

Enhanced AccessChannel

Reverse CommonControl Channel

0 or 1 ReverseDedicated Control

Channel

0 or 1 ReverseFundamental

Channel

0 to 2 ReverseSupplemental

Channels

Power ControlSubchannel

Fig 5

2.1) Reverse Link Physical Layer Characteristics

2.1.1) Continuous Waveform


١٦

The cdma2000 system provides a continuous waveform for all data rates.

This includes a continuous pilot and continuous data-channel waveforms.

This continuous waveform minimizes biomedical interference to devices

such as hearing aids and pacemakers. It also permits a range increase at

lower transmission rates. The continuous waveform also enables the

interleaving to be performed over the entire frame, rather than just the

Portions that are not gated off. This enables the interleaving to achieve the full

benefit of the frame time diversity. The base station uses the pilot for multipath

searches, tracking, coherent demodulation, and to measure the quality of the link

for power-control purposes.

The cdma2000 system uses separate orthogonal channels for the pilot and

each of the data channels. Hence, the relative levels of the Pilot and the

physical data channels can easily be adjusted without changing the frame

structure or power levels of some symbols of a frame. Also, this

flexibility is provided with no performance degradation relative to an

approach where the pilot is only sent in short bursts.

2.1.2) Orthogonal Channels Provided Using Different Length Walsh

Sequences (OVSF)

The cdma2000 system uses orthogonal channels for the Pilot and the other

physical data channels. Using different length Walsh sequences, with the higher

rate channels using shorter Walsh sequences provides these orthogonal channels.

Short Walsh sequences allow high encoder output rates to be accommodated. The

cdma2000 system takes advantage of this by using a low code rate. The

channelization codes are orthogonal variable spreading factor (OVSF) codes that

preserve the orthogonality between a user's different physical channels and support

multiple data rates. To generate an orthogonal set of functions, the Walsh and


١٧

Hadamard sequences make useful sets for wireless-CDMA. Walsh functions are

generated by mapping codeword rows of special square matrices called Hadamard

Matrices. The Hadamard matrix of desired length can be generated by the

following recursive procedure:

The OVSF codes can be generated using code tree below:

The generated codes of the same layer form a set of Walsh functions and they are

orthogonal. Also, any two codes of different layers are orthogonal except for the

case that one of the two codes is a mother code of the other. We can choose an


١٨

appropriate spreading code according to the transmission rate. However, a code in

the code tree can be used by a mobile station iff no other code on the path from the

specific code to the root of the tree or in the subtree below the specific code is

used by the same mobile station. Thus, the information signal Xk (t) is firstly

coded by the channelization code Cok and subsequently scrambled by a

scrambling code Cs. All the channels of one cell use the same scrambling code

whereas; the different cells use different, distinct scrambling codes. Use of two

codes in two steps is referred to as Multiple spreading. Similarly, for the uplink,

each mobile requires a channelization code for transmission to the base station in a

serving cell. Further, a distinct scrambling code is assigned to each mobile. Thus,

all the mobiles in a cell have a common set of Channelization codes and a

separate, distinguished scrambling code.

Both in the uplink and downlink, the scrambling operation is complex .This

complex scrambling is used to equalize the power levels in the I and Q channels

because unequal power levels result in a strange constellation. Mathematically,

complex scrambling performs the multiplication of two complex signals: the

complex signal Ic+jQc which is already spread using channelization code and the

complex scrambling signal Is+jQs.


١٩

Thus, the amplitude of the resulting signal I + jQ is the product of amplitude of

both the signals and phase is the sum of their phase. So, when the two channels (I

and Q) have unequal amplitudes, the amplitude of the resulting constellation is

also constant.

The family of scrambling codes : Maximal length PN sequences (m-

sequence): The long PN codes used in wireless CDMA are of period N= 2^42-1

with feedback characteristic polynomial to be X41+X3+1 .These long codes are

truncated to form a cycle of 2^15 bits for its implementation as a scrambling code.

The truncated sequences are selected through computer simulation. Extensive

search is required for the sequences with minimum cross-correlation values.

1) DIRECT SEQUENCE SPREADING CAN BE DONE AT BOTH BASE

STATION AND MOBILE STATION


٢٠

UPLINK SPREADING WITH MORE DETAILS


٢١

2) MULTICARRIER SPREADING ONLY AT BASE STATION

Variable data rate capacity, essential for next generation mobile communication

systems, is achieved by using orthogonal channelization codes. Two-step multiple

spreading provides flexibility and distinguishability amongst all users (uplink &


٢٢

downlink), while complex scrambling helps in equalizing power in the I & Q

branches

2.1.3) Rate Matching

The cdma2000 system uses several approaches to match the data rates to

the Walsh spreader input rates. These include adjusting the code rate,

using puncturing, symbol repetition, and sequence repetition. The general

design approach is to first try to use a low rate code, but to not reduce the

rate below R = 1/4 since the gains of smaller rates would be small and the

decoder implementation complexity would increase.

2.1.4) Low Spectral Sidelobes

The cdma2000 system achieves low spectral sidelobes with non-ideal mobile

power amplifiers by splitting the physical channels between the in-phase (I) and

quadrature (Q) data channels and by using a complex-multiply-type PN spreading

approach.

2.1.5) Independent Data Channels

The cdma2000 system provides two types of physical data channels

(Fundamental and Supplemental) on the reverse link that can each be

adapted to a particular type of service. The use of Fundamental and

Supplemental Channels enables the system to be optimized for multiple

simultaneous services. These channels are separately coded and


٢٣

interleaved and may have different transmit power levels and frame error

rate set points. Each channel carries different types of services depending

on the service scenarios.

2.1.6) Power-Control

2.1.6.1) Reverse Power Control DONE FOR MS.

There are three components of reverse power control: open loop, closed loop, and

outer loop. Open loop power control sets the transmit power based upon the power

that is received at the mobile station. Open loop power control compensates for the

path loss from the mobile station to the base station and handles very slow fading.

Closed loop power control consists of an 800 bps feedback loop from the base

station to the mobile station to set the transmit power of the mobile station. Closed

loop power control compensates for medium to fast fading and for inaccuracies in

open loop power control.

Outer loop power control is implementation specific but typically adjusts

the closed loop power control threshold in the base station in order to

maintain a desired frame error rate.

2.1.6.2) Forward Power Control DONE FOR BS.

The power of the forward link channels for a specific user is adjusted at a

rate of 800 bits per second. The forward power control information is

time-multiplexed with the reverse link pilot.

2.1.7) Separate Dedicated Control Channel


٢٤

The cdma2000 reverse link includes a separate low rate, low power,

continuous, orthogonal, Dedicated Control Channel. This allows for a

flexible Dedicated Control Channel structure that does not impact the

other pilot and physical channel frame structures.

2.1.8) Frame Length

The cdma2000 system supports 5 and 20 ms frames for control information on the

Fundamental and Dedicated Control Channels, and uses 20 ms frames for other

types of data (including voice). Interleaving and sequence repetitions are over the

entire frame interval. This provides improved time diversity over systems that use

shorter frames.

The 20 ms frames are used for voice. A shorter frame would reduce one

component of the total voice delay, but degrade the demodulation performance

due to the shorter interleaving span.

2.1.9) Direct-Spread Chip Rate

The cdma2000 system uses a chip rate that is a multiple of the TIA/EIA-95-B chip

rate of 1.2288 Mcps, and nominal channel spacing that are a multiple of 1.25

MHz. This channel spacing provides a flexible and convenient spacing for carrier

frequency allocations of 5, 10, 15, and 20 MHz.

2.2) Reverse Link Modulation and Coding

The cdma2000 reverse link uses direct-sequence spreading with the

TIA/EIA-95-B chip rate of 1.2288 Mcps (denoted as a 1X chip rate) or

chip rates that are 3, 6, 9, or 12 times the TIA/EIA-95-B chip rate. Higher


٢٥

chip rate systems are denoted as 3X, 6X, 9X, and 12X and they are

respectively operated at 3.6864, 7.3728, 11.0592, and 14.7456 Mcps.

The 1X system can be used anywhere that a TIA/EIA-95-B reverse link is

used. An IA/EIA-95-B reverse link carrier frequency can also be shared

with mobiles transmitting the TIA/EIA-95-B waveform and those

transmitting the 1X cdma2000 waveform. The higher chip rate reverse

links can be used in applications where larger bandwidth allocations are

available. Mobiles that support a higher chip rate would typically also

support the 1X chip rate. This will allow these mobiles to access base

stations that only support the 1X chip rate and allow operators with larger

bandwidth allocations the flexibility of using a mixture of 1X and higher

chip rate systems.

Within an operator’s allocated band, the 1X cdma2000 reverse links

would typically occupy the same bandwidth as TIA/EIA-95-B reverse

link systems (i.e., 1.25 MHz) and higher chip rate cdma2000 links would

typically occupy a bandwidth that is 1.25 MHz

Times the higher chip rate factor. A guard band of 1.25 MHz/2 = 625 kHz

would typically be used on both sides of the operator’s allocated band.

The Reverse CDMA Channel is composed of Reverse Common Channels

and Reverse Dedicated Channels.

The mobile station to initiate communications with the base station and to

respond to Forward Link Paging Channel messages uses the Reverse

Common Channel. The Reverse Common Channel uses a random-access

protocol. Reverse Common Channels are uniquely identified by their long

code.


٢٦

The Reverse Dedicated Channel may be used for the transmission of user

traffic, control, and signaling information to the base station.

2.3) Reverse Dedicated Channel

2.3.1) Walsh and PN Spreading

Reverse Dedicated Channels consist of up to several physical channels: a

Reverse Pilot Channel, which is always used, and a Reverse Fundamental

Channel (R-FCH), one or more Reverse Supplemental Channels

(R-SCH), and a Reverse Dedicated Control Channel (R-DCCH). The

R-FCH, R-SCH, R-DCCH may or may not be used depending on the

service scenario. Each physical channel is spread with a Walsh code

sequence to provide orthogonal channelization among these physical

channels. The spread Pilot and R- DCCH are mapped to the in-phase

(I) data channel. The spread R-FCH and R-SCH are mapped to the

quadrature (Q) data channel. Then, the I and Q data channels are

Spread using a complex-multiply PN spreading approach. Figure 9.6

shows this Reverse Dedicated Channel structure.

The Supplemental Channel (R-SCH) is spread using a two bit Walsh

function. Optionally two Supplemental Channels (denoted as R-SCH1

and R-SCH2 on Figure 9.6) can be accommodated to support bearer

service profiles where more than one R-SCH is needed. In that case both

Supplemental Channels are spread using a four bit Walsh functions

(reducing the maximum supported data rate of each Supplemental for 1X,


٢٧

3X, and 6X). R-SCH1 is mapped to the I Channel and R-SCH2 is mapped

to the Q channel.

Additional Supplemental Channels can be accommodated by increasing

the Walsh length for Supplemental Channel to 8 bits and mapping

additional R-SCHs to the I and Q channel.

The quadrature direct-sequence spreading uses the TIA/EIA-95-B

I-channel and Q-channel PN sequences. These sequences have a period of

2^15 chips. So for the 1X chip rate they repeat 75 times in 2 seconds

(i.e., once every 26.66 ms).

The TIA/EIA-95-B long code, with a period of 2^42 – 1 chips, is used for

all of the chip rates.


٢٨

+

+

RelativeGain

RelativeGain

RelativeGain

+

+

Notes :1. Binary signals are represented with ±1 values

with the mapping +1 for ‘0’ and –1 for ‘1’.Unused channels and gated-off symbols arerepresented with zero values.

2. When the Reverse Common Control Channel orEnhanced Access Channel is used, the onlyadditional channel is the Reverse Pilot Channel.

3. All of the pre-baseband-filter operations occurat the chip rate.

Complex Multiplier

–

+

+

+

BasebandFilter

BasebandFilter

cos(2π fct)

sin(2π fct)

GainWalsh Cover(+ + + + + + + + – – – – – – – – )

Walsh Cover(+ + + + – – – – + + + + – – – – )

Walsh Cover(+ – ) or (+ + – – )

for Reverse Supplemental Channel(+ + + + – – – – )

for Reverse Common Control Channeland Enhanced Access Channel

B

C

C

ReversePilot

Channel

ReverseSupplemental

Channel 1, ReverseCommon Control

Channel, or EnhancedAccess Channel

ReverseFundamental

Channel

ReverseDedicated

Control Channel

Σ

Σ

Σ

Σ

Σ

Decimatorby Factor

of 2

Walsh Cover(+ – )

C

A

RelativeGain

+

ReverseSupplemental

Channel 2

Walsh Cover(+ + – – ) or (+ + – – – – + +)

s(t)

1-ChipDelay

LongCode

Generator

Q-ChannelPN Sequence

I-ChannelPN Sequence

Long CodeMask

Fig 6

Figure 6 shows the physical channels separated by orthogonal Walsh

functions and the I and Q channel in phase quadrature. The I data channel

and the Q data channel are labeled as DI and DQ, respectively.

The Reverse Pilot Channel is used for initial acquisition, time tracking,

Rake-receiver coherent reference recovery, and power-control

measurements. The levels of the Fundamental, Supplemental, and

Dedicated Control Channels are adjusted relative to the Reverse Pilot

Channel by using the gains GF, GS, and GC. These are slow adjustments

to adapt to different coding and interleaving and to adapt to different

propagation conditions.

Reverse Dedicated Channel


٢٩

2.3.2) Reverse Pilot Channel (R-PICH)

The Pilot Channel for the Reverse Dedicated Channels consists of a fixed

reference value and multiplexed forward Power-Control (PC) information

as illustrated in Figure 34. This time multiplexed forward Power Control

information is referred to as the power control sub-channel. This sub-

channel provides information on the quality of the forward link at the rate

of 1 bit per 1.25 ms Power-Control Group (PCG) and is used by the

forward link channels to adjust their power. The power-control symbol

repetition means that the 1-bit value is constant for that repeated-symbol

duration. The power-control bit uses the last portion of each power-

control group.

The +1 pilot symbols and the multiplexed power-control symbols are all

sent with the same power level. The binary power-control symbols are

represented with ±1 values in Figure 7.

1

1/2

1/4

1.25 msGatingRate

5 ms20 ms

PCPilot

Fig 7

9.2.3.3) Reverse Fundamental Channel (R-FCH)


٣٠

Figure 6, Figure 7, and Figure 8 describe the modulation for the Reverse

Fundamental Channel (R-FCH). This channel supports 5 and 20 ms

frames. The 20 ms frame structures provide rates derived from the

TIA/EIA-95-B Rate Set 1 or Rate Set 2 rate sets. The 5 ms frames

provide 24 information bits per frame with a 16-bit CRC.

Within each 20 ms frame interval, either one 20 ms R-FCH structure, up

to four 5 ms R-FCH structure(s), or nothing can be transmitted.

2.3.4) Reverse Supplemental Channel (R-SCH)

The Supplemental Channel (R-SCH) can be operated in two distinct

modes as shown on Figure 6. The first mode is used for data rates not

exceeding 14.4 kbps. In the second mode, the base station explicitly

knows the rate information.

In the first mode, the variable rates provided are those derived from the

TIA/EIA-95-B Rate Set 1 (RS1) and Rate Set 2 (RS2). The structures for

the variable-rate modes are identical to the 20 ms Reverse Fundamental

Channel (R-FCH) structures followed by a 2-symbol repetition factor.

This repetition factor compensates for the shorter Walsh sequence of the

R-SCH compared to that of the R-FCH.

When two Supplemental Channels are used (R-SCH1 and R-SCH2) each

Supplemental Channel is spread using a four bit Walsh sequence. Since

the R-FCH is also spread by a four bit Walsh sequence, the 2 symbol

repetition factor is removed in the case when two Supplemental Channels

are being used.


٣١

In the second mode, the high data rate modes can have convolutional

coding with K = 9, or turbo coding with two K = 4 component encoders.

Figure11, Figure 12, Figure 13, Figure 14, and Figure 15 give the R-SCH

structures for the high data rate modes with K = 9 convolutional coding

and 1X, 3X, 6X, 9X, and 12X chip rates. With turbo coding, the

structures are changed as follows:

• The K = 9 encoder is replaced by a turbo encoder with the

same basic (before puncturing) rate.

• The 8-bit encoder tail is replaced by a 6-bit encoder tail.

• Two reserved bits are added after the 6-bit encoder tail to

keep the number of information bits constant regardless of the

encoding method. Reverse Fundamental Channel and Reverse Supplemental Channel Structure for Radio Configuration 3

Notes:1. The 5 ms frame is only used for the Reverse Fundamental Channels, and only rates of 9.6 kbps or less are used for

Reverse Fundamental Channels.2. Turbo coding may be used for the Reverse Supplemental Channels with rates of 19.2 kbps or more; otherwise, K = 9

convolutional coding is used.3. With convolutional coding, the Reserved/Encoder Tail bits provide an encoder tail. With turbo coding, the first two

of these bits are reserved bits that are encoded and the last six bits are replaced by an internally generated tail.4. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4).

Bits/Frame Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps)24 (5 ms) 16 9.6 1/4 2× None 384 76.8

16 6 1.5 1/4 16× 1 of 5 1,536 76.840 6 2.7 1/4 8× 1 of 9 1,536 76.880 8 4.8 1/4 4× None 1,536 76.8172 12 9.6 1/4 2× None 1,536N 76.8

360 16 19.2 1/4 1× None 1,536N 76.8744 16 38.4 1/4 1× None 3,072N 153.6

1,512 16 76.8 1/4 1× None 6,144N 307.23,048 16 153.6 1/4 1× None 12,288N 614.46,120 16 307.2 1/2 1× None 12,288N 614.4

Convolutionalor TurboEncoder

SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator

Add 8Reserved/EncoderTail Bits

ChannelBits

C

Table 6

Reverse Fundamental Channel and Reverse Supplemental Channel Structure for Radio Configuration 4


٣٢





Bits/Frame Bits Bits Rate (kbps) R Factor Deletion Symbols Rate (ksps)24 (5 ms) 0 16 9.6 1/4 2× None 384 76.8

21 1 6 1.8 1/4 16× 8 of 24 1,536 76.855 1 8 3.6 1/4 8× 8 of 24 1,536 76.8125 1 10 7.2 1/4 4× 8 of 24 1,536 76.8267 1 12 14.4 1/4 2× 8 of 24 1,536N 76.8

552 0 16 28.8 1/4 1× 4 of 12 1,536N 76.81,128 0 16 57.6 1/4 1× 4 of 12 3,072N 153.62,280 0 16 115.2 1/4 1× 4 of 12 6,144N 307.24,584 0 16 230.4 1/4 1× 4 of 12 12,288N 614.4

ChannelBits


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


AddReserved

BitsC

Table 7

Reverse Fundamental Channel and Reverse Supplemental Channel Structure for Radio Configuration 5






16 6 1.5 1/4 16× 1 of 5 1,536 76.840 6 2.7 1/4 8× 1 of 9 1,536 76.880 8 4.8 1/4 4× None 1,536 76.8172 12 9.6 1/4 2× None 1,536N 76.8

360 16 19.2 1/4 1× None 1,536N 76.8744 16 38.4 1/4 1× None 3,072N 153.6

1,512 16 76.8 1/4 1× None 6,144N 307.23,048 16 153.6 1/4 1× None 12,288N 614.46,120 16 307.2 1/3 1× None 18,432N 921.612,264 16 614.4 1/3 1× None 36,864N 1,843.2


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


ChannelBits

C

Table8


٣٣






21 1 6 1.8 1/4 16× 8 of 24 1,536 76.855 1 8 3.6 1/4 8× 8 of 24 1,536 76.8125 1 10 7.2 1/4 4× 8 of 24 1,536 76.8267 1 12 14.4 1/4 2× 8 of 24 1,536N 76.8

552 0 16 28.8 1/4 1× None 2,304N 115.21,128 0 16 57.6 1/4 1× None 4,608N 230.42,280 0 16 115.2 1/4 1× None 9,216N 460.84,584 0 16 230.4 1/4 1× None 18,432N 921.69,192 0 16 460.8 1/4 1× None 36,864N 1,843.220,712 0 16 1,036.8 1/2 1× 2 of 18 36,864N 1,843.2

ChannelBits


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


AddReserved

BitsC

Table 9

2.3.5) Reverse Common Channel

The Reverse Access Channel (R-ACH) and the Reverse Common Control

Channel (R-CCCH) are common channels used for communication of

messages from the mobile station to the base station. The R-CCCH

differs from the R-ACH in that the R-CCCH offers extended capabilities

beyond the Reverse Access Channel (R-ACH).

The R-ACH and R-CCCH are multiple access channels as mobile stations

transmit without explicit authorization by the base station. The Reverse

Access Channel and Reverse Common Control Channel use a slotted

Aloha type of mechanisms with higher capture probabilities due to the

CDMA properties of the channel (simultaneous transmission of multiple

users).

Reverse Fundamental Channel and Reverse Supplemental Channel Structure for Radio

Configuration 6


٣٤

There can be one or more access channels per frequency assignment.

Different access channels are distinguished by different long codes.

The Reverse Common Control Channel (R-CCCH) uses a physical

structure similar to the Reverse Access Channel (R-ACH). The main

difference between the R-CCCH and the R-ACH is in the addition of

frame sizes of 5 and 10 ms as well as data rates of 19.2 and 38.4 kbps.

The R-CCCH may use the same long codes as the R-ACH or they may

use different long codes.

.

2.4) Access Channel

The Access Channel is used by the mobile station to initiate

communication with the base station and to respond to Paging Channel

messages. An Access Channel transmission is a coded, interleaved, and

modulated spread-spectrum signal. The Access Channel uses a random-

access protocol. Access Channels are uniquely identified by their long

codes.

The mobile station shall transmit information on the Access Channel at a

fixed data rate of 4800 bps. An Access Channel frame shall be 20 ms in

duration. An Access Channel frame shall begin only when System Time

is an integral multiple of 20 ms.

The Reverse CDMA Channel may contain up to 32 Access Channels

numbered 0 through 31 per supported Paging Channel. At least one

Access Channel exists on the Reverse CDMA Channel for each Paging

Channel on the corresponding Forward CDMA Channel. Each Access

Channel is associated with a single Paging Channel.


٣٥

Each Access Channel frame contains 96 bits (20 ms frame at 4800 bps).

Each Access Channel frame shall consist of 88 information bits and eight

Encoder Tail Bits (see Figure 8). The channel structure for spreading

rate1 is shown in figure.

Access Channel Frame Structure

88 8

96 bits (20ms)

Information Bits T

Notation

T - Encoder Tail Bits

4800 bpsFrame

Channel Structure for the Header on the Enhanced Access Channel for

spreading Rate 1 fig. 8


64-aryOrthogonalModulator

BlockInterleaver

(576Symbols)

RepeatedCode Symbol

Modulation Symbol(Walsh Chip)

4.8 ksps(307.2 kcps)

28.8 ksps

LongCode

Generator

Long CodeMask 1.2288 Mcps

Add 8EncoderTail Bits

AccessChannel

Bits

88 Bits/Frame(4.4 kbps)

ConvolutionalEncoder

R = 1/3, K = 9

CodeSymbol

4.8 kbps

RepeatedCode

SymbolSymbolRepetition 28.8 ksps

I

Σs(t)

cos(2π fct)

BasebandFilter

sin(2π fct)

Q ChannelGain

Signal PointMapping0 → +11 → –1

1/2 PNChipDelay


BasebandFilter

ChannelGain


Fig 9


٣٦

The Access Channel preamble shall consist of frames of 96 zeros that are

transmitted at the 4800 bps rate. The Access Channel preamble is

transmitted to aid the base station in acquiring an Access Channel

transmission.

2.4.1) Enhanced Access Channel

The Enhanced Access Channel is used by the mobile station to initiate

communication with the base station or to respond to a mobile station

directed message. The Enhanced Access Channel can be used in one of

three possible modes: Basic Access Mode, Power Controlled Access

Mode, and Reservation Access Mode.

When operating in the Basic Access Mode, the mobile station shall not

transmit the Enhanced Access header on the Enhanced Access Channel.

In Basic Access Mode, the access probe shall consist of an Enhanced

Access Channel preamble, followed by Enhanced Access data.

When operating in the Power Controlled Access Mode, the Enhanced

Access Channel probe shall consist of an Enhanced Access Channel

preamble, followed by an Enhanced Access header and Enhanced Access

data.

When operating in the Reservation Access Mode, the Enhanced Access

Channel probe shall consist of an Enhanced Access Channel preamble,

followed by an Enhanced Access header. Enhanced Access data is sent on

the Reverse Common Control Channel upon receiving permission from

the base station.


٣٧

The Enhanced Access Channel uses a random-access protocol. Enhanced

Access Channels are uniquely identified by their long codes. The

Enhanced Access Channel probe structure is shown in Figure 9.10

Enhanced Access Channel Probe Structure

Enhanced AccessChannel Preamble

EnhancedAccess Header

PreambleTransmission

(See Figure 2.1.3.4.2.3-1)

Tx Power

Reverse PilotChannel

Enhanced AccessData

Preamble

1.25 ms

EnhancedAccess Data

Reverse Pilot Channel Transmission

Enhanced AccessHeader

Not transmitted inBasic Access Mode

Not transmitted inReservation Access Mode

5 ms (1 to RACH_MAX_CAP_SZ) x 5 ms

Fig 10

The mobile station shall transmit the Enhanced Access header on the

Enhanced Access Channel at a fixed data rate of 9600 bps. The mobile

station shall transmit the Enhanced Access data on the Enhanced Access

Channel at a fixed data rate of 9600, 19200, or 38400 bps.

The frame duration for the Enhanced Access header on the Enhanced

Access Channel shall be 5 ms in duration. The frame duration for the

Enhanced Access data on the Enhanced Access Channel shall be 20, 10,

or 5 ms in duration.


٣٨

An Enhanced Access Channel frame of 20, 10, or 5 ms duration shall

begin only when System Time is an integral multiple of 20, 10, or 5 ms

respectively.

The Reverse CDMA Channel may contain up to 32 Enhanced Access

Channels per Forward Common Control Channel supported, numbered 0

through 31. There is a Forward Common Assignment Channel associated

with every Enhanced Access Channel operating in the Power Controlled

Access Mode or the Reservation Access Mode.

Table 10 summarizes the Enhanced Access Channel bit allocations.

Enhanced Access Channel Frame Structure Summary

Number of Bits per Frame

Frame

Length (ms)

Frame

Type

Transmissio

n Rate (bps)

Total

Bits

Informatio

n Bits

Frame

Quality

Indicator

Encoder

Tail Bits

5 Header 9600 48 32 8 8

20 Data 9600 192 172 12 8

20 Data 19200 384 360 16 8

20 Data 38400 768 744 16 8

10 Data 19200 192 172 12 8

10 Data 38400 384 360 16 8

5 Data 38400 192 172 12 8

Table10

Enhanced Access Channel header frames shall consist of 48 bits. These

48 bits shall be composed of 32 information bits followed by eight frame

quality indicator (CRC) bits and eight Encoder Tail Bits, as shown in


٣٩

Enhanced Access Channel Frame Structure for the Enhanced Access

Header

32 8 8

48 bits (5ms)

Information Bits F T

9600 bpsFrame

Notation

F - Frame Quality Indicator (CRC)T - Encoder Tail Bits

Fig 11 Channel Structure for the Header

on the Enhanced Access Channel for Spreading Rate 1


R = 1/4, K = 9

SymbolRepetition(4× Factor)


BlockInterleaver

(768Symbols)

ModulationSymbols

C

153.6 ksps9.6 kbps

EnhancedAccess

ChannelBits

32 Bits per5 ms Frame

Add 8-BitFrameQuality

Indicator

Fig.12

Channel for the Header on the Enhanced Access Channel

for Spreading Rate 3


R = 1/4, K = 9



BlockInterleaver

(768Symbols)

C

153.6 ksps9.6 kbps

EnhancedAccess

ChannelBits

32 Bits per5 ms Frame


Indicator

Fig 13


٤٠

172 12 8

192 bits (20ms)


9600 bpsFrame

172 12 8

192 bits (10ms)


19200 bpsFrame

172 12 8

192 bits (5ms)


38400 bpsFrame

Notation

F - Frame Quality Indicator (CRC)T - Encoder Tail Bits

360 16 8

384 bits (20ms)


19200 bpsFrame

744 16 8

768 bits (20ms)


38400 bpsFrame

360 16 8

384 bits (10ms)


38400 bpsFrame

Fig 14

Enhanced Access Channel Frame Structure


٤١

+

+

RelativeGain

RelativeGain

RelativeGain

+

+

Notes :1. Binary signals are represented with ±1 values

with the mapping +1 for ‘0’ and –1 for ‘1’.Unused channels and gated-off symbols arerepresented with zero values.

2. When the Reverse Common Control Channel orEnhanced Access Channel is used, the onlyadditional channel is the Reverse Pilot Channel.

3. All of the pre-baseband-filter operations occurat the chip rate.

Complex Multiplier

–

+

+

+

BasebandFilter

BasebandFilter

cos(2π fct)

sin(2π fct)

GainWalsh Cover(+ + + + + + + + – – – – – – – – )

Walsh Cover(+ + + + – – – – + + + + – – – – )

Walsh Cover(+ – ) or (+ + – – )

for Reverse Supplemental Channel(+ + + + – – – – )

for Reverse Common Control Channeland Enhanced Access Channel

B

C

C

ReversePilot

Channel

ReverseSupplemental

Channel 1, ReverseCommon Control

Channel, or EnhancedAccess Channel

ReverseFundamental

Channel

ReverseDedicated

Control Channel

Σ

Σ

Σ

Σ

Σ

Decimatorby Factor

of 2

Walsh Cover(+ – )

C

A

RelativeGain

+

ReverseSupplemental

Channel 2

Walsh Cover(+ + – – ) or (+ + – – – – + +)

s(t)

1-ChipDelay

LongCode

Generator



Long CodeMask

Fig15 Channel Structure for the Data on the Enhanced Access Channel and the Reverse

Common Control Channel for Spreading Rate 1

Bits/Frame Bits Rate (kbps) Factor Symbols Rate (ksps)172 (5 ms) 12 38.4 1× 768 153.6360 (10 ms) 16 38.4 1× 1,536 153.6172 (10 ms) 12 19.2 2× 1,536 153.6744 (20 ms) 16 38.4 1× 3,072 153.6360 (20 ms) 16 19.2 2× 3,072 153.6172 (20 ms) 12 9.6 4× 3,072 153.6


R = 1/4, K = 9

SymbolRepetition

AddFrameQuality

Indicator



Bits

BlockInterleaver

ModulationSymbols

C

Fig 16

I and Q Mapping for Enhanced Access Channel, Reverse Common Control Channel, and Reverse Traffic Channel

with Radio Configurations 3 and 4


٤٢

Bits/Frame Bits Rate (kbps) Factor Symbols Rate (ksps)172 (5 ms) 12 38.4 1× 768 153.6360 (10 ms) 16 38.4 1× 1,536 153.6172 (10 ms) 12 19.2 2× 1,536 153.6744 (20 ms) 16 38.4 1× 3,072 153.6360 (20 ms) 16 19.2 2× 3,072 153.6172 (20 ms) 12 9.6 4× 3,072 153.6


R = 1/4, K = 9

SymbolRepetition

AddFrameQuality

Indicator



Bits

BlockInterleaver C

Fig 17

The last eight bits of each Enhanced Access Channel frame are called the

Encoder Tail Bits. These eight bits shall be set to ‘0’.

Each transmission on the R-ACH or R-CCCH (denoted as an access

probe) consists of an Access Preamble and an Access Channel Message

Capsule. The Access Preamble is a transmission of only the non-data

bearing Reverse Pilot Channel (R-PICH) at an increased power level; the

Access Channel Message Capsule transmission consists of the data

bearing R-ACH or R-CCCH and the associated, non-data bearing Reverse

Pilot Channel.

2.4.2) Reverse Pilot Channel and the Access Preamble

The Reverse Pilot Channel associated with the Reverse Access Channel

or Reverse Common Control Channel has a similar structure to the

Reverse Pilot Channel used when the mobile station is communicating

with the base station in a dedicated mode. The key difference is that the

Reverse Pilot Channel associated with the Reverse Access Channels does

not have a Power Control sub-channel and therefore no Power Control

bits are time-multiplexed with the Reverse Pilot Channel. The Reverse

Channel Structure for the Data on the Enhanced Access Channel and the

Reverse Common Control Channel for Spreading Rate 3


٤٣

Pilot Channel associated with the Reverse Access Channels consists of an

all ‘0’ channel.

The Access preamble consists of transmissions only on the Reverse Pilot

Channel. The preamble length is an integer number of 1.25 ms intervals.

A zero length preamble (no preamble) is permitted. The number of 1.25

ms intervals to be used is indicated by the base station. The preamble

length depends upon the rate at which the base station can search the PN

space, the cell radius, and the multipath characteristics of the cell.

The base station search rate is dependent upon the hardware configuration

of the cell. When more possible PN hypotheses can be searched in

parallel, then the base station can acquire the mobile station faster.

Similarly, when the cell radius is larger, the number of PN hypotheses

increases. In addition, different multipath conditions may make

combining losses higher or have more fading, resulting in more

accumulations being required for a given probability of detection.

The preamble for the R-ACH and R-CCCH is transmitted at a specified

power setting stronger than the Reverse Pilot Channel depending upon

data rate and mobile station power limitations. If the mobile station must

reduce its R-ACH or R-CCCH transmission rate due to insufficient output

power, then the mobile station transmits the preamble

(as well as the access probe itself) at the maximum available power.


٤٤

2.5) Slotting and Channel Arrangement

Access probe transmissions are slotted. The slot is long enough to

accommodate the preamble and the longest message. The base station

indicates the slot length. The transmission must begin at the beginning of

the slot; the transmission is not required to last any longer than the

number of frames required to transmit the message.

To reduce delay, the slotting for different access channels can be offset.

The acquisition process is substantially simpler due to the system slotted

design. The base station attempts to acquire mobile station at the

beginning of slots, during the time in which the mobile station would

send the acquisition preamble.

2.5.1) Reverse Common Control Channel

The Reverse Common Control Channel is used for the transmission of

user and signaling information to the base station when Reverse Traffic

Channels are not in use.

A Reverse Common Control Channel transmission is a coded,

interleaved, and modulated spread-spectrum signal. The mobile station

transmits during intervals specified by the base station. Reverse Common

Control Channels are uniquely identified by their long codes. The

Reverse Common Control Channel preamble and data transmission

structure is shown in Figure 18.


٤٥

Preamble and Data Transmission for the Reverse Common Control Channel

Reverse CommonControl Channel

Preamble

Reverse Common Control ChannelData

20, 10, or 5 ms

Reverse Pilot Channel Transmission

Reverse Common Control ChannelTransmission


(See Figure 2.1.3.5.2.3-1)

Tx Power

ReversePilot

Channel


Preamble

1.25 ms

Fig 18

The mobile station shall transmit information on the Reverse Common

Control Channel at variable data rates of 9600, 19200, and 38400 bps. A

Reverse Common Control Channel frame shall be 20, 10, or 5 ms in

duration. A Reverse Common Control Channel frame of 20, 10, or 5 ms

duration shall begin only when System Time is an integral multiple of 20,

10, or 5 ms respectively.

The Reverse CDMA Channel may contain up to 32 Reverse Common

Control Channels numbered 0 through 31 per supported Forward

Common Control Channel. At least one Reverse Common Control

Channel exists on the Reverse CDMA Channel for each Forward

Common Control Channel on the corresponding Forward CDMA


٤٦

Channel. Each Reverse Common Control Channel is associated with a

single Forward Common Control Channel.

Table 11 summarizes the Reverse Common Control Channel bit

allocations.

All frames shall consist of the information bits, followed by a frame

quality indicator (CRC) and eight Encoder Tail.

Reverse Common Control Channel Frame Structure Summary

Number of Bits per Frame

Frame

Length

(ms)

Transmission

Rate

(bps)

Total Information

Frame

Quality

Indicator

Encoder

Tail Bits

20 9600 192 172 12 8

20 19200 384 360 16 8

20 38400 768 744 16 8

10 19200 192 172 12 8

10 38400 384 360 16 8

5 38400 192 172 12 8

Table 11

The last eight bits of each Reverse Common Control Channel frame are

called the Encoder Tail Bits. These eight bits shall be set to ‘0’.

The Reverse Common Control Channel preamble is transmitted to aid the

base station in acquiring a Reverse Common Control Channel

transmission.

The Reverse Common Control Channel preamble is shown in

Figure 19. The Reverse Common Control Channel preamble is a


٤٧

transmission of only the non-data-bearing Reverse Pilot Channel at an

increased power level. The Reverse Pilot Channel associated with the

Reverse Common Control Channel does not have a power control sub

channel. The total preamble length shall be an integer number of 1.25 ms.

A zero length preamble (no preamble) is permitted. The Reverse

Common Control Channel preamble shall consist of a sequence of

fractional preambles and one additional preamble.

Preamble for the Reverse Common Control Channel


(See Figure 2.1.3.5-1)

P AP PB B

FractionalPreamble 1

FractionalPreamble 2

FractionalPreamble N

AdditionalPreamble

T

N = RCCCH_PREAMBLE_NUM_FRACs + 1P = RCCCH_PREAMBLE_FRAC_DURATIONs + 1) * 1.25 msB = RCCCH_PREAMBLE_OFF_DURATIONs * 1.25 msA = RCCCH_PREAMBLE_ADD_DURATIONs * 1.25 msT = N (P + B) + A = RCCCH_PREAMBLE_TOTAL_DURATION * 1.25 ms

Fig 19

9.2.5.2) Reverse Common Channel Procedures

The procedures for the R-CCCH are essentially the same as the R-ACH.


٤٨

9.2.5.3) Access Attempts

The entire process of sending one message and receiving (or failing to

receive) an acknowledgment for that message on the R-ACH is called an

access attempt. One access attempt consists of one or more access sub-

attempts. Each sub-attempt consists of one or more access probe

sequences. Each transmission in an access probe sequence is called an

access probe. The access sub-attempt is shown in more detail in Figure

20.


٤٩

2.5.4) Access Probe Sequences

Within an access probe sequence, the mobile station transmits at

successively higher powers. The first probe of a sequence is transmitted

at a power level given by the open loop power level plus two offsets

which are indicated to the mobile station by the base station, plus an

adjustment for the R-ACH transmission rate. The first offset is the Initial

Power (IP) offset which is the nominal offset power that corrects for the

open loop power control imbalance between the forward and reverse

links. The second offset is the Power Increment (PI). This adjusts the

received level at the base station for access probes relative to dedicated

channel transmissions. As shown in Figure 20, each successive probe

within a probe sequence is transmitted at a level that is PI greater

compared to the previous probe (after taking into account the open loop

change). The mobile station transmits probes at corresponding higher

powers until an acknowledgment is received, a complete sequence of

probes is transmitted, it performs an access probe handoff, or it fails the

access attempt. The number of probes in a sequence is determined by

parameters indicated by the base station. If a complete sequence of probes

has been transmitted, then the mobile station can transmit another

sequence beginning at the original power setting. The maximum number

of sequences is also determined by parameters indicated by the base

station.

2.6) Access Probe Handoff

If the mobile station is unable to receive the forward link or if a

neighboring base station is sufficiently strong, the mobile station may


٥٠

stop the access probe sequence and perform an access probe handoff. The

overhead messages provide the mobile station with the set of base stations

to which the mobile station is permitted to perform an access probe

handoff.

When the mobile station performs an access probe handoff, the mobile

station adjusts its receiver, by changing the F-PICH PN offset, to receive

the neighboring base station. Depending upon the configuration of the

neighboring base station, the mobile station may have to change the code

channels or the long codes that it is using. Whether this must be done, and

the correct code channels to use, is provided by the overhead messages.

When the mobile station performs an access probe handoff, it begins a

new access sub-attempt. The overhead messages indicate the maximum

number of access sub-attempts that are permitted. Each access sub-

attempt also has the mobile station begin a new access probe sequence.

2.7) Randomization between Probes and Sequences

Because there are collisions (multiple simultaneous transmissions which

the bases station cannot simultaneously receive), the time of

retransmission should be randomized so that the retransmissions will not

collide again. Whenever an acknowledgment is not received to a probe

(after a time-out period denoted by TA on Figure 9.20), the mobile station

waits a random time, called the probe backoff, before beginning the next

access probe. The probe backoff is shown by RT in Figure 20. Between


٥١

access probe sequences, a different random time interval is used (called

the sequence backoff) which is given by RS in Figure 20.

Main blocks in the system physical layer in details:

2.7.1) Convolutional Codes :

The cdma2000 reverse link uses a K=9, R=1/4 convolutional code for the

Fundamental Channel (R-FCH). The better codeword distance a property

of this low rate code provides performance gains versus higher rate codes

in fading and Additive White Gaussian Noise (AWGN) channel

conditions. The constraint-length K = 9, R = 1/4 convolutional code

provides a gain of approximately 0.5 dB over a K = 9, R = 1/2 (Used in

IS-95) code even in AWGN. The Supplemental Channel (RSCH) uses

convolutional codes for data rates up to 14.4 kbps. Convolutional codes

for higher data rates on the Supplemental Channel are optional and the

use of Turbo codes is preferred. For some of the highest data rates R=1/3

and R=1/2 codes are used.

The parameters of the convolutional codes used are given in Table 12

(polynomials given in octal).

Reverse Link Convolutional Codes Polynomials Table 12

Rate Constraint

Length (K)

Generator

Polynomial

g0

Generator

Polynomial

g1

Generator

Polynomial

g2

Generator

Polynomial

g3

1/2 9 753 561 N/A N/A

1/3 9 557 663 711 N/A

1/4 9 765 671 513 473


٥٢

2.7.2) Turbo Codes

A common constituent code is used for reverse link Turbo codes of rate

1/4, 1/3, and 1/2 for all Supplemental Channels (R-SCH). The generator

polynomials for this constituent code are given in Table 13 (polynomials

given in octal).

Reverse Link Turbo Codes Polynomials

Rate Constraint

Length (K)

Generator

Polynomial d

(feedback)

Generator

Polynomial n0

(Y0)

Generator

Polynomial n1

(Y1)

1/2,1/3,1/4 4 15 13 17

Table 13

2.7.3) Block Interleaving

The mobile station shall interleave all repeated code symbols and

subsequent puncturing, if used, on the Access Channel, the Enhanced

Access Channel, and the Reverse Common Control Channel, and the

Reverse Traffic Channel prior to modulation and transmission.

For the Reverse Traffic Channel with Radio Configurations 1 and 2, the

interleaver shall be an array with 32 rows and 18 columns (i.e., 576 cells).

Repeated code symbols shall be written into the interleaver by columns

from the first column to the eighteenth column filling the complete 32

matrix. Reverse Traffic Channel repeated code symbols shall be output

from the interleaver by rows. For Radio Configuration 1 and 2, the

interleaver rows shall be output in the following order:


٥٣

At 9600 or 14400 bps:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

28 29 30 31 32

At 4800 or 7200 bps:

1 3 2 4 5 7 6 8 9 11 10 12 13 15 14 16 17 19 18 20 21 23 22 24 25 27 26

28 29 31 30 32

At 2400 or 3600 bps:

1 5 2 6 3 7 4 8 9 13 10 14 11 15 12 16 17 21 18 22 19 23 20 24 25 29 26

30 27 31 28 32

At 1200 or 1800 bps:

1 9 2 10 3 11 4 12 5 13 6 14 7 15 8 16 17 25 18 26 19 27 20 28 21 29 22

30 23 31 24 32

For the Access Channel, the Enhanced Access Channel, the Reverse

Common Control Channel, and the Reverse Traffic Channel with Radio

Configurations 3, 4, 5, and 6, the symbols input to the interleaver are

written sequentially at addresses 0 to the block size (N) minus one.

The mobile station may support interleaving over 2 or 4 consecutive

frames on the Reverse Supplemental Channel at data rates of 9600 bps or

higher as specified by MULTI_FRAME_LENGTHs.

The structure of the n-frame block interleaver (n = 2 or 4) is the same as a

single frame interleaver. However, the block size of the interleaver is

extended to n times the block size for a single interleaver

2.8) Orthogonal Modulation and Spreading


٥٤

When transmitting on the Access Channel or the Reverse Traffic Channel

with Radio Configurations 1 and 2, the mobile station uses orthogonal

modulation. When transmitting on the Enhanced Access Channel, the

Reverse Common Control Channel, or the Reverse Traffic Channel in

Radio Configuration 3 through 6, the mobile station uses orthogonal

spreading.

2.8.1) Orthogonal Modulation

When operating in Radio Configuration 1 or 2, modulation for the

Reverse CDMA Channel shall be 64-ary orthogonal modulation. One of

64 possible modulation symbols is transmitted for each six repeated code

symbols. The modulation symbol shall be one of 64 mutually orthogonal

waveforms generated using Walsh functions. The modulation symbols

shall be selected according to the following formula:

Modulation symbol index = c0 + 2c1 + 4c2 + 8c3 + 16c4 + 32c5,

Where c5 shall represent the last (or most recent) and c0 the first (or

oldest) binary valued (‘0’ and ‘1’) repeated code symbol of each group of

six repeated code symbols that form a modulation symbol index.

The period of time required to transmit a single modulation symbol shall

be equal to 1/4800 second (208.333... µs). The period of time associated

with one sixty-fourth of the modulation symbols is referred to as a Walsh

chip and shall be equal to 1/307200 second (3.255... µs).

Within a modulation symbol, Walsh chips shall be transmitted in the

order of 0, 1, 2... 63


٥٥

2.8.2) Orthogonal Spreading

When operating in Radio Configuration 3, 4, 5, or 6, the mobile station

shall use orthogonal spreading. Table 14 specifies the Walsh functions

that are applied to the Reverse CDMA Channels.

Walsh Functions for Reverse CDMA Channels

Channel Type Walsh Function

Reverse Pilot Channel 320W

Enhanced Access Channel 84W

Reverse Common Control

Channel 8

4W

Reverse Dedicated Control

Channel 16

8W

Reverse Fundamental Channel 164W

Reverse Supplemental Channel 1 21W or 4

2W

Reverse Supplemental Channel 2 42W or 8

6W

Table 14

Since the Walsh function operations occur at the chip rate, this post-

interleaver symbol repetition factor is the number of Walsh function

sequence repetitions per interleaver output symbol.

When a mobile station only supports one Reverse Supplemental Channel,

it should support Reverse Supplemental Channel 1. Reverse

Supplemental Channel 1 should use Walsh Function W24 when possible.

2.9) Discontinuous Transmission


٥٦

2.9.1) Rates and Gating

When operating with Radio Configuration 1 or 2, the Reverse Code

Channel interleaver output stream is time-gated to allow transmission of

certain interleaver output symbols and deletion of others. This process is

illustrated in Figure 20. As shown in the figure, the duty cycle of the

transmission gate varies with the transmit data rate. When the transmit

data rate is 9600 or 14400 bps, the transmission gate allows all interleaver

output symbols to be transmitted. When the transmit data rate is 4800 or

7200 bps, the transmission gate allows one-half of the interleaver output

symbols to be transmitted, and so forth. The gating process operates by

dividing the 20 ms frame into 16 equal length (i.e., 1.25 ms) periods,

called power control groups (PCG). Certain power control groups are

gated-on (i.e., transmitted), while other groups are gated-off (i.e., not

transmitted).

The assignment of gated-on and gated-off groups, referred to as the data

burst randomizing function. The gated-on power control groups are

pseudo randomized in their positions within the frame. The data burst

randomizer ensures that every code symbol input to the repetition process

is transmitted exactly once.

When transmitting on the Access Channel, the code symbols are repeated

once (each symbol occurs twice) prior to transmission. The data burst

randomizer is not used when the mobile station transmits on the Access

Channel. Therefore, both copies of the repeated code symbols are

transmitted.

When transmitting on the Enhanced Access Channel the data rate for the

Enhanced Access header shall be fixed at 9600 bps. The data rate for the


٥٧

message portion shall not vary over the message when transmitting on the

Enhanced Access Channel or the Reverse Common Control Channel.

Gating is not used on the Enhanced Access Channel or the Reverse

Common Control Channel.

2.9.2) Data Burst Randomizing Algorithm The data burst randomizer generates a masking pattern of ‘0’s and ‘1’s

that randomly masks out the redundant data generated by the code

repetition. The masking pattern is determined by the data rate of the

frame and by a block of 14 bits taken from the long code. These 14 bits

shall be the last 14 bits of the long code used for spreading in the previous

to the last power control group of the previous frame (see Figure 20). In

other words, these are the 14 bits which occur exactly one power control

group (1.25 ms) before each Reverse Code Channel frame boundary.

These 14 bits are denoted as

b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 b10 b11 b12 b13,

Where b0 represents the oldest bit and b13 represents the latest bit.

Reverse CDMA Channel Variable Data Rate Transmission for Radio Configurations 1 and 2

Example


٥٨

Previous Frame

12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 9600 bps and14400 bps frames

Code symbols transmitted:1 33 65 97 ... 481 513 545 2 34 66 98 ... 482 514 546

Previous Frame

12 13 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


Previous Frame

12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


Previous Frame

12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


b0

b1

b2

b3

b4

b5

b6

b7

b8

b9

b10

b11

b12

b13

PN bits usedfor scrambling

PCG 14 PCG 15

Sample masking streams shownare for the 14-bit PN sequence:(b0, b1, ..., b13) = 0 0 1 0 1 1 0 1 1 0 0 1 0 0

Power Control Group number

4800 bps and7200 bps frames



=

Groups Control Power 16symbols modulation 96

symbols code 576ms 20

=

Group Control Power 1symbols modulation 6

symbols code 36ms 1.25

14

Fig 20

2.10) Mobile station Receive diversity: The ordinary rake receiver shown in Fig 21 is modified in Fig 22 to get

advantage of the Orthogonal Transmit Diversity done at the BS.

Fig 21


٥٩

Fig 22

Additional integrators for the pilot and data channels for OTD. The hot topic today is the use of mobile station receive diversity 2 micro strip antennas are embedded in the mobile station for the purpose of Rx diversity.


٦٠


٦١

Use of diversity reception at the mobile improves the capacity of forward link.

MS Diversity Combining Schemes: • MMSE Combining – Minimum Mean Squared Error Combining – Weights for each path are chosen to give Minimum of the Mean Square Error (MMSE) between the combined voltage stream and the signal • MRC Combining – Maximal Ratio Combining – For each path, signals from the antennas are combined Proportional to the SNR of that path – When noise and interference for a path are uncorrelated between the two antennas, MRC is equivalent to MMSE


٦٢

Diversity Receive Handset • 1900 MHz PCS handset • Modified to include an additional antenna and receiver


٦٣

• Primary antenna is the original extendable whip antenna used for both transmits and receive • Secondary antenna is a Wire Inverted-F Antenna (WIFA) used only for second receive chain

Conclusion Increasing Capacity with Receiver Diversity: • Only practical with CDMA • Backward compatible with CDMA systems • Does not require a new interoperability standard • Transparent to the operation of the network and users • Can be rolled out at a chosen pace – Geographical distribution – Customer profile


٦٤

– Capacity improvement is simply proportional to the usage of diversity handsets

Vocoder of CDMA2000

The Selectable Mode Vocoder (SMV) is a breakthrough technology that provides significant capacity and quality gains on cdmaOne and CDMA2000 systems. A vocoder converts the spoken word into digital code and vice versa. The global standards body, 3GPP2, with support from the CDG, recently completed the development of the SMV algorithm and released it for implementation. The state-of-the-art technology utilized in SMV will allow CDMA subscribers to enjoy superior quality while allowing service providers to increase capacity as needed.

Furthermore, SMV offers CDMA carriers the flexibility to tradeoff small quality losses vs. large system capacity gains. Wireless operators can gain up to 75% increase in system capacity compared to the current CDMA vocoders by using the lower encoding rates of SMV. Wireless operators can also provide improvements in voice quality by using data rates similar to the current CDMA vocoders. SMV operational mode can be controlled on a static or dynamic basis, allowing carriers further efficiency in service at peak loaded times


٦٥

3) Forward link The forward link supports chip rates of N X 1.2288 Mcps (N = 1, 3, 6, 9, 12). For

N = 1, the spreading is similar to IS-95-B, however QPSK modulation and fast

closed loop power control are employed. There are two options for chip rates

corresponding to N > 1: multi-carrier and direct spread.

The multi-carrier approach de-multiplexes modulation symbols onto N separate

1.25 MHz carriers (N = 3, 6, 9, 12). Each carrier is spread with a 1.2288 Mcps

chip rate.

The N > 1 direct spread approach transmits modulation symbols on a single

carrier which is spread with a chip rate of N X 1.2288 Mcps

(N = 3, 6, 9, 12). Figure 21 shows both configurations for a system of 3 times the

IS-95-B bandwidth.

Fig

Fig 21


٦٦

3.1) Forward Link Physical Layer Characteristics 3.1.1) Independent Data Channels

The cdma2000 system provides two types of forward link physical data channels

(Fundamental and Supplemental) that can each be adapted to a particular type of

service. The use of Fundamental and Supplemental Channels enables the system to

be optimized for multiple simultaneous services. The two physical channels are

separately coded and interleaved and in general have different transmit power

levels.

3.1.2) Orthogonal Modulation:

To reduce or eliminate intra-cell interference, each forward link physical channel

is modulated by a Walsh code. To increase the number of usable Walsh codes,

QPSK modulation is employed prior to spreading. Every two information bits are

mapped into a QPSK symbol. As a result, the available number of Walsh codes is

increased by a factor of two relative to BPSK (pre-spreading) symbols.

Furthermore, the Walsh code length varies to achieve different information bit

rates.

The forward link may be interference limited or Walsh code limited depending on

the specific deployment and operating environment. When a Walsh code limit

occurs, additional codes may be created by multiplying Walsh codes by the

masking functions. The codes created in this way are called Quasi-Orthogonal

Functions.

3.1.3) Transmit Diversity:


٦٧

Transmit diversity can reduce the required Ec/Ior (required transmit power per

channel) and thus enhance capacity. Transmit diversity can be implemented in

different ways:

a) Multi-Carrier Transmit Diversity:

Antenna diversity can be implemented in a multi-carrier forward link with no

impact on the subscriber terminal, where a subset of the carriers is transmitted on

each antenna. This provides improved frequency diversity and hence increases

forward link capacity.

In addition, antennas can be substantially separated to provide good spatial

diversity.


٦٨

b) Direct-Spread Transmit Diversity:

Orthogonal Transmit Diversity (OTD) may be used to provide transmit diversity

for direct spread. The implementation of OTD is as follows. Coded bits are split

into two data streams and are transmitted via separate antennas. A different

orthogonal code is used per antenna for spreading. This maintains the

orthogonality between the two output streams, and hence self-interference is

eliminated in flat fading. Note that by splitting the coded data into two separate

data streams, the effective number of spreading codes per user is the same as the

case without OTD because we double the length of the Walsh code used. An

Auxiliary Pilot is introduced for the additional antenna. Note: the data rates are

constant as before the OTD.


٦٩

C) The use of smart antennas

Beam Switching Overview – Fixed beams technology (from 3 to 4) within existing sectors – Same pilot in one sector illuminates all beams – Compatible with all IS-95A/B, CDMA2000 1X, 1xEV-DV Voice capacity gains estimated to be between 1.8X and 2.3X (Voice) over a 3 sector site


٧٠

Beam Steering Overview – Adaptive beam per user – Potential impacts on Asics and requires calibration – More sophisticated method – Voice capacity gains 2X to 3X (Voice) over 3 sector sites

• Smart antennas are a cost effective means of increasing voice/data capacity – Increases capacity and/or coverage – Can increase capacity in excess of 2X relative to 3 sectors • Switched/Steered beams yield best performance across technologies given constraints – Number of antennas, cables, amplifiers, visual profile – Standards • Capacity of 1xEV-DV shared channel increased by using switched beams with 2-user CDM Note: Given limitations on resources (antennas, cables, amplifiers), the gains from beamwidth reduction are typically larger than diversity

3.1.4) Rate Matching:

The cdma2000 system uses several approaches to match the data rates to the

Walsh spreader input rates. These include adjusting the code rate, using symbol

repetition with or without symbol puncturing, and sequence repetition.

Specifically, sub rates of speech signals are generated by symbol repetition and by


٧١

symbol puncturing when necessary. A Supplemental Channel rate not equal to a

given channel data rate is realized by sequence repetition or by symbol repetition

with symbol puncturing to match the desired channel data rate. Both of these rate-

matching approaches provide flexibility in matching data rates to channel rates.

3.1.5) Frame Length

The cdma2000 system supports 5 and 20 ms frames for control information on the

Fundamental and Dedicated Control Channels, and uses 20 ms frames for other

types of data (including voice). Interleaving and sequence repetition are over the

entire frame interval. This provides improved time diversity over systems that use

shorter frames. The 20 ms frames are used for voice.

3.1.6) Forward Error Correction

a) Convolutional Codes

The cdma2000 forward link uses K=9 convolutional codes for the Fundamental

Channel (F-FCH). The Supplemental Channel (F-SCH) uses K=9 convolutional

codes for rates up to and including 14.4 kbps. Convolutional codes for higher data

rates on the F-SCH are optional and Turbo codes are preferred.

The parameters of the convolutional codes used for the forward link are given

Turbo Codes:

The Forward Supplemental Channel (F-SCH) uses Turbo codes with K=4, R =

1/4, 1/3, and 1/2. Turbo codes for data rates greater than 14.4 kbps are preferred.


٧٢

Turbo codes have been shown to provide near Shannon capacity limit performance

over Additive White Gaussian Noise (AWGN) channels by means of an iterative,

soft-input/soft-output decoding algorithm and, thus, significantly outperform

conventional convolutional codes of similar decoding complexity. As the capacity

of all CDMA technologies is highly dependent on the operating Eb /No, improved

performance translates directly to higher capacity. The general Turbo code

encoder is shown in Figure 21 The Turbo encoder employs two systematic

recursive convolutional codes connected in parallel, with an interleaver (the

“Turbo interleaver”) preceding the second recursive convolutional encoder. Information bits

3.2) Radio configurations for the forward traffic

channel:

3.3) Channel Structure:

Parity Bits

Interleaver

Constituent encoder #1

Constituent encoder #2

Parity Bits

Puncture

Fig 21


٧٣

Fig 22

Figure 22 shows the forward CDMA channels transmitted by the base station.

Each of these code channels is orthogonally spread by the appropriate Walsh or

quasi-orthogonal function and is then spread by a quadrature pair of PN sequences

at a fixed chip rate of 1.2288 Mcps. Multiple Forward CDMA Channels may be

used within a base station in a frequency division multiplexed manner.

3.4) Forward Common Channels:

Pilot channel

s

Common control

channels

Sync. Channels

Traffic channels

Quick paging channel

Paging channels

(RS1)

Broadcast channels

Forward Pilot

channel

Transmit diversity Pilot

channel

Auxiliary Pilot

Channels

0-1 Dedicated Control Channel

0-1 Fundamental

Channel

MS Power Control Sub

channel

0-7 Supplemental Code Channels Radio

configuration 1-2

0-2 Supplemental Channels Radio

Configuration 3-9

Forward channel for spreading rates 1 and 3


٧٤

The forward common channels use a long code mask and spreading that is known

by all mobile stations. The functional capabilities provided by the forward

common channels include: soft handoff, coherent detection, paging, and

synchronization and data communications.

3.4.1) Pilot Channel (F-PICH):

The pilot channel spreads the all 0’s sequence with Walsh code 0. The channel is

continuously broadcast throughout the cell in order to provide timing and phase

information. The pilot is shared between all mobiles in the cell and is used to

obtain fast acquisition of new multipath and channel estimation (i.e., phase and

multipath strength).

3.4.2) Forward Common Auxiliary Pilot (F-CAPICH):

Certain applications such as antenna arrays and antenna transmit diversity require

a separate pilot for channel estimation and phase tracking. Auxiliary Pilots are

code multiplexed with other forward link channels and use orthogonal Walsh

codes. Common Auxiliary Pilots are used with antenna beam-forming applications

to generate spot beams. Spot beams can be used to increase coverage towards a

particular geographical point or to increase capacity towards hot spots. The

Common Auxiliary Pilot can be shared among multiple mobile stations in the

same spot beam.

3.4.3) Forward Sync Channel (F-SYNC):

The Sync Channel is used by mobile stations operating within the coverage area

of the base station to acquire initial time synchronization.

3.4.4) Forward Paging Channel (F-PCH):


٧٥

A cdma2000 system can have multiple Paging Channels per base station. A

Paging Channel can transmit at a data rate of 9600 bps or 4800 bps.

PilotChannels(All 0’s)

Bits/20 ms Rate (kbps) Rate (ksps) Factor Rate (ksps)96 4.8 9.6 2× 19 .2192 9.6 19.2 1× 19 .2

1.2288 Mcps

LongCode

Generator

Long CodeMask forPaging

Channel p


R = 1/2, K = 9

PagingChannel

Bits

CodeSymbol

SymbolRepetition

ModulationSymbol

BlockInterleaver

(384Symbols)

ChannelGain


ModulationSymbol

XI

XQ0


R = 1/2, K = 9

SyncChannel

Bits

CodeSymbol


ModulationSymbol

BlockInterleaver

(128Symbols)

ModulationSymbol

32 Bits/26.666... ms Frame

(1.2 kbps)

2.4 ksps 4.8 ksps

ChannelGain


XI

XQ0


19.2 ksps

19.2 ksps

Decimator

ChannelGain


XI

XQ0

Figure 23

Figure shows the structure of: Pilot Channels, Sync Channel, and Paging

Channels for Spreading Rate 1


٧٦

PilotChannels(All 0’s)

XI

XQ0

ChannelGain


XI

XQ0

BlockInterleaver

(384Symbols)

ModulationSymbol

ChannelGain


14.4 ksps

CodeSymbol


ModulationSymbol

3.6 ksps


R = 1/3, K = 9

SyncChannel

Bits

32 Bits/26.666... ms Frame

(1.2 kbps)

Figure shows the structure of: Forward Pilot Channel, Auxiliary Pilot Channels,

and Sync Channel for Spreading Rate 3

The modulation parameters for spreading rate 1:

3.5) Broadcast Channel:

The Broadcast Channel is an encoded, interleaved, spread, and modulated spread

spectrum signal that is used by mobile stations operating within the coverage area

of the base station. The Broadcast Channel shall be spread by a Walsh or quasi-

orthogonal function.


٧٧

BlockInterleaver

(1,536 Symbols)

ChannelGain


Decimator

ModulationSymbolSequence

Repetition(1, 2, or 4

Times)

Long CodeGenerator

Long CodeMask for

BroadcastChannel


Indicator

Add 8-BitEncoder

Tail


R = 1/2, K = 9

Broadcast Channel Bits(744 Information Bitsper 40, 80, or 160 ms

Broadcast Channel Slot)

X38.4 ksps

Broadcast Channel Structure for Spreading Rate 1 Fig 25

Modulation Parameters for Spreading Rate 1

Table 17

Data Rate (bps) Parameter 19200 9600 4800 Units PN Chip Rate 1.2288 1.2288 1.228

8 Mcps

Code Rate 1/2 1/2 ½ bits/code symbol Code Sequence Repetition

1 2 4 modulation symbols/ code symbol*

Modulation Symbol Rate

38,400 38,400 38,400

sps

Walsh Length 64 64 64 PN chips/modulation symbol

Processing Gain 64 128 256 PN chips/bit


٧٨

BlockInterleaver

(2,304 Symbols)

ChannelGain


Decimator

ModulationSymbolSequence

Repetition(1, 2, or 4

Times)

Long CodeGenerator

Long CodeMask for

BroadcastChannel


Indicator

Add 8-BitEncoder

Tail


R = 1/3, K = 9

Broadcast Channel Bits(744 Information Bitsper 40, 80, or 160 ms

Broadcast Channel Slot)

X57.6 ksps

Broadcast Channel Structure for Spreading Rate 3

Fig 26

Broadcast Channel Modulation Parameters for Spreading Rate 3

9.3.6) Quick Paging Channel:

The Quick Paging Channel is an un-coded, spread and on-off Keying modulated

spread spectrum signal that is used by mobile stations operating within the

coverage area of the base station. The base station uses the Quick Paging Channel

to inform mobile stations operating in the Slotted mode while in the idle state

whether or not they should the forward Common Control Channel or the Paging

Channel starting in the next Forward Common Control Channel or Paging

Channel frame.

Quick Paging ChannelIndicators

(9.6 or 4.8 ksps)

SymbolRepetition(2× or 4×Factor)

ModulationSymbol Signal Point Mapping

+1 When Indicator Enabled0 Otherwise

ChannelGain X

Fig 27

Quick Paging Channel Structure for Spreading Rate 1


٧٩

Quick Paging ChannelIndicators

(9.6 or 4.8 ksps)

SymbolRepetition(3× or 6×Factor)

ModulationSymbol Signal Point Mapping

+1 When Indicator Enabled0 Otherwise

ChannelGain X

Fig 28 Quick Paging Channel Structure for Spreading Rate 3

3.7) Forward Common Control Channel:

The Forward Common Control Channel is an encoded, interleaved, spread, and

modulated spread spectrum signal that is used by the mobile stations operating

within the coverage area of the base station. The base Station uses the Forward

Common Control Channel to transmit system overhead information and mobile

station overhead messages.

ChannelGain


BlockInterleaver

Add 8-BitEncoder

Tail


R = 1/4, K = 9

ForwardCommonControlChannel

Bits

ModulationSymbols

Bits/Frame Rate (kbps) Symbols Rate (ksps)184 (5 ms) 38.4 768 153.6184 (10 ms) 19.2 768 76.8376 (10 ms) 38.4 1,536 153.6184 (20 ms) 9.6 768 38.4376 (20 ms) 19.2 1,536 76.8760 (20 ms) 38.4 3,072 153.6

DecimatorLong CodeGenerator

Long CodeMask for

Forward CommonControl Channel

X

Fig 29

Forward Common Control Channel Structure for Spreading Rate 1 with R = 1/4 Mode Forward Common Control

Channel Modulation Parameters


٨٠

For Spreading Rate 1 with R = 1/4

. Forward Common Control Channel Structure

for Spreading Rate 3

ChannelGain


BlockInterleaver

Add 8-BitEncoder

Tail


R = 1/3, K = 9

ForwardCommonControlChannel

Bits

ModulationSymbols

Bits/Frame Rate (kbps) Symbols Rate (ksps)184 (5 ms) 38.4 576 115.2184 (10 ms) 19.2 576 57.6376 (10 ms) 38.4 1,152 115.2184 (20 ms) 9.6 576 28.8376 (20 ms) 19.2 1,152 57.6760 (20 ms) 38.4 2,304 115.2

DecimatorLong CodeGenerator

Long CodeMask for

Forward CommonControl Channel

X

Fig 30

Data Rate (bps) Parameter 38,400 19,200 9600 Units PN Chip Rate 1.2288 1.2288 1.2288 Mcps Code Rate 1/4 1/4 ¼ bits/code symbol Code Symbol Repetition

1 1 1 modulation symbols/code symbol*


153,600 76,800 38,400 sps

Walsh Length 16 32 64 PN chips/modulation symbol

Processing Gain 32 64 128 PN chips/bit

Table 21

Table 22


٨١

3.8) Forward Dedicated Channels:

3.8.1) Forward Dedicated Control Channel:

The Forward Dedicated Control Channel is used for the transmission of user and

signaling information to a specific mobile station during a call. Each Forward

Traffic Channel may contain one Forward Dedicated Control Channel. The F-

DCCH shall be convolutionally encoded.

Bits/Frame Bits Rate (kbps) Symbols Rate (ksps)24 (5 ms) 16 9.6 192 38.4

172 (20 ms) 12 9.6 768 38.4


R = 1/4, K = 9

AddFrameQuality

Indicator


ForwardDedicatedControlChannel

Bits

BlockInterleaver

ModulationSymbols

W

Fig 31

Forward Dedicated Control Channel Modulation Parameters for Radio

Forward Dedicated Control Channel Structure for Radio Configuration 6


172 (20 ms) 12 9.6 1,152 57.6


R = 1/6, K = 9

AddFrameQuality

Indicator



Bits

BlockInterleaver

ModulationSymbols

W

Forward Dedicated Control Channel Modulation Parameters for Radio

Configuration 6


٨٢



172 (20 ms) 12 9.6 576 28.8


R = 1/3, K = 9

AddFrameQuality

Indicator



Bits

BlockInterleaver

ModulationSymbols

W



172 (20 ms) 12 9.6 576 28.8


R = 1/3, K = 9

AddFrameQuality

Indicator



Bits

BlockInterleaver

ModulationSymbols

W

Fig 34

Forward Dedicated Control Channel Modulation Parameters for Radio Configuration 7

Data Rate (bps)

Parameter 9600 Units PN Chip Rate 3.6864 Mcps Code Rate 1/3 bits/code symbol Code Symbol Repetition 1 Modulation

symbols/code symbol


28,800 Sps

Walsh Length 256 PN chips/modulation symbol

Processing Gain 384 PN chips/bit Table 24



٨٣

Bits/Frame Bits Bits Rate (kbps) R Factor Symbols Rate (ksps)24 (5 ms) 0 16 9.6 1/3 2× 288 57.6

267 (20 ms) 1 12 14.4 1/4 1× 1,152 57.6


Bits


SymbolRepetition

AddFrameQuality

Indicator


AddReserved

Bits

BlockInterleaver W

ModulationSymbols

Fig 35

3.9) Forward Traffic Channel:

They are used to transmit voice and data applications at a variable rate. The Traffic

Channel can be classified into two classes which they are the Forward

Fundamental Channel and the Forward Supplemental Channel.

3.10) Forward Fundamental Channel:

This channel is transmitted at variable rate as in IS-95-B and consequently

requires rate detection at the receiver. Each F-FCH is transmitted on a different

orthogonal code channel and supports frame sizes corresponding to 20 ms and 5

ms. we can find that convolutional encoder is employed with different code rates.

The choice of the code rate can be made depending on the radio environment. The

1/2 code rate will allow two times the number of Walsh codes as the rate 1/4 code

at the cost of FEC (Forward Error Correction) performance.

Forward Supplemental Channel:

The Supplemental Channel (F-SCH) can be operated in two distinct modes. The

first mode is used for data rates not exceeding 14.4 kbps and uses blind rate

detection (no scheduling or rate information provided). In The second mode the


٨٤

rate information is explicitly provided to the base station (no blind rate detection is

performed).

In the first mode, the variable rates provided are those derived from the IS-95-B

Rate Set 1 (RS1) and Rate Set 2 (RS2). The structures for the variable rate modes

are identical to the 20 ms F-FCH. In the second mode, the high data rate modes

can have K = 9 convolutional coding or turbo coding with K = 4 component

encoders. For the case of convolutional codes, there are 8 tail bits. For the case of

Turbo codes, there are 6 tail bits and 2 reserve bits.

There may be more than one F-SCHs in use at a given time. The individual F-SCH

target FERs may be set independently with respect to the F-FCH and other F-

SCHs, since the optimal FER set point for data is in general different than for

voice. For classes of data services that have less stringent delay requirements, the

FER may also be managed by retransmissions.

Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio

Configuration 3


16 6 1.5 1/4 8× 1 of 5 768 38.440 6 2.7 1/4 4× 1 of 9 768 38.480 8 4.8 1/4 2× None 768 38.4172 12 9.6 1/4 1× None 768N 38.4

360 16 19.2 1/4 1× None 1,536N 76.8744 16 38.4 1/4 1× None 3,072N 153.6

1,512 16 76.8 1/4 1× None 6,144N 307.23,048 16 153.6 1/4 1× None 12,288N 614.4


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


W

ModulationSymbols

ChannelBits

Notes:1. The 5 ms frame is only used for the Forward Fundamental Channels, and only rates of 9.6 kbps or less are used for

Forward Fundamental Channels.2. Turbo coding may be used for the Forward Supplemental Channels with rates of 19.2 kbps or more; otherwise, K = 9



Fig 36


٨٥

Forward Fundamental Channel and Forward Supplemental Channel Modulation

Parameters for Radio Configuration 3

Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration 4






16 6 1.5 1/2 8× 1 of 5 384 19.240 6 2.7 1/2 4× 1 of 9 384 19.280 8 4.8 1/2 2× None 384 19.2172 12 9.6 1/2 1× None 384N 19.2

360 16 19.2 1/2 1× None 768N 38.4744 16 38.4 1/2 1× None 1,536N 76.8

1,512 16 76.8 1/2 1× None 3,072N 153.63,048 16 153.6 1/2 1× None 6,144N 307.26,120 16 307.2 1/2 1× None 12,288N 614.4


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


W

ModulationSymbols

ChannelBits

Fig 37


٨٦



Forward Fundamental Channels.2. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4).


16 6 1.5 1/6 8× 1 of 5 1,152 57.640 6 2.7 1/6 4× 1 of 9 1,152 57.680 8 4.8 1/6 2× None 1,152 57.6172 12 9.6 1/6 1× None 1,152N 57.6

360 16 19.2 1/6 1× None 2,304N 115.2744 16 38.4 1/6 1× None 4,608N 230.4

1,512 16 76.8 1/6 1× None 9,216N 460.83,048 16 153.6 1/6 1× None 18,432N 921.66,120 16 307.2 1/6 1× None 36,864N 1,843.2


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


W

ModulationSymbols

ChannelBits

Fig 38



Forward Fundamental Channels.2. N is the number of consecutive 20 ms frames over which the interleaving is done (N = 1, 2, or 4).


16 6 1.5 1/6 8× 1 of 5 1,152 57.640 6 2.7 1/6 4× 1 of 9 1,152 57.680 8 4.8 1/6 2× None 1,152 57.6172 12 9.6 1/6 1× None 1,152N 57.6

360 16 19.2 1/6 1× None 2,304N 115.2744 16 38.4 1/6 1× None 4,608N 230.4

1,512 16 76.8 1/6 1× None 9,216N 460.83,048 16 153.6 1/6 1× None 18,432N 921.66,120 16 307.2 1/6 1× None 36,864N 1,843.2


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


W

ModulationSymbols

ChannelBits

Fig 39


٨٧

Forward Fundamental Channel and Forward Supplemental Channel Modulation Parameters for 20 ms Frames for Radio Configuration 6


٨٨

Data Rate (bps) Parameter 9600×N 4800 2700 1500 Units

PN Chip Rate 3.6864 3.6864

3.6864

3.6864

Mcps

Code Rate 1/6 1/6 1/6 1/6 bits/code symbol Code Symbol Repetition

1 2 4 8 repeated symbols/ code symbol

Puncturing Rate

1 1 8/9 4/5 modulation symbols/ repeated symbol


57,600×N

57,600

57,600

57,600

sps

Walsh Length

128/N 128 128 128 PN chips/ modulation symbol

Processing Gain

384/N 768 1365.3

2457.6

PN chips/bit






16 6 1.5 1/3 8× 1 of 5 576 28.840 6 2.7 1/3 4× 1 of 9 576 28.880 8 4.8 1/3 2× None 576 28.8172 12 9.6 1/3 1× None 576N 28.8

360 16 19.2 1/3 1× None 1,152N 57.6744 16 38.4 1/3 1× None 2,304N 115.2

1,512 16 76.8 1/3 1× None 4,608N 230.43,048 16 153.6 1/3 1× None 9,216N 460.86,120 16 307.2 1/3 1× None 18,432N 921.612,264 16 614.4 1/3 1× None 36,864N 1,843.2


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


W

ModulationSymbols

ChannelBits

Fig 40




٨٩





Bits/Frame Bits Bits Rate (kbps) R Factor Symbols Rate (ksps)24 (5 ms) 0 16 9.6 1/3 2× 288 57.6

21 1 6 1.8 1/4 8× 1,152 57.655 1 8 3.6 1/4 4× 1,152 57.6125 1 10 7.2 1/4 2× 1,152 57.6267 1 12 14.4 1/4 1× 1,152N 57.6

552 0 16 28.8 1/4 1× 2,304N 115.21,128 0 16 57.6 1/4 1× 4,608N 230.42,280 0 16 115.2 1/4 1× 9,216N 460.84,584 0 16 230.4 1/4 1× 18,432N 921.69,192 0 16 460.8 1/4 1× 36,864N 1,843.2

ChannelBits


SymbolRepetition

AddFrameQuality

Indicator


AddReserved

Bits

BlockInterleaver W

ModulationSymbols

Fig 41

Forward Fundamental Channel and Forward Supplemental Channel Structure for Radio Configuration






21 1 6 1.8 1/2 8× None 576 28.855 1 8 3.6 1/2 4× None 576 28.8125 1 10 7.2 1/2 2× None 576 28.8267 1 12 14.4 1/2 1× None 576N 28.8

552 0 16 28.8 1/2 1× None 1,152N 57.61,128 0 16 57.6 1/2 1× None 2,304N 115.22,280 0 16 115.2 1/2 1× None 4,608N 230.44,584 0 16 230.4 1/2 1× None 9,216N 460.89,192 0 16 460.8 1/2 1× None 18,432N 921.620,712 0 16 1,036.8 1/2 1× 2 of 18 36,864N 1,843.2

ChannelBits


SymbolRepetition

SymbolPuncture

BlockInterleaver

AddFrameQuality

Indicator


AddReserved

BitsW

ModulationSymbols

Fig 42

3.11) Power Control Subchannel: A power control sub-channel is transmitted only on the Forward Fundamental


٩٠

Channel or the Forward Dedicated Control Channel. When the mobile station is

operating in the transmission mode, the sub-channel shall transmit at a rate of one

bit (0 or 1) every 1.25 ms (800 bps). The 20 ms frame is divided into 16 power

control groups (PCG). The long code mask is used to determine the location of the

power control bit in each PCG.

Long Code Generation, Power Control, and Signal Point Mapping for Forward

Traffic Channels

Power control symbol puncturing is on the Forward Fundamental Channels and Forward Dedicated Control Channels only.The decimator output rate matches the modulation symbol rate.

PowerControl

Bit PositionExtractor

ChannelGain


PowerControl

SubchannelGain

PowerControlSymbol

PuncturePower Control

Bits±1 Values16 Bits per

20 ms Frameor 4 Bits per5 ms Frame

Puncture TimingControl (800 Hz)

X

DecimatorLongCode

Generator

Long CodeMask

for User m

W

Fig 43

3.12) Symbol De-multiplexing:

Symbol de-multiplexing is performed on every code channel in the forward

CDMA channels. The Forward Pilot channel, the Transmit Diversity Pilot

channel, the Auxiliary Pilot channel, Paging channel and the Forward Traffic

channel with Radio configurations 1 and 2 shall be de-multiplexed using the non-

OTD de-multiplexer only (the OTD and MC de-multiplexers are not allowed). The

Broadcast channels, the Quick Paging, the Forward Common Control channels,


٩١

and Forward Traffic channels with Radio configuration 3 through 9 shall be de-

multiplexed using the non-OTD, OTD, or MC mode.

Demultiplexer Structure for Spreading Rate 1

b) OTD Mode

a) Non-OTD Mode

DEMUXXI

YI1

YI2DEMUX

DEMUXXQ

YQ1

YQ2

YI1

YI2

YQ1

YQ2

X

XI YI

DEMUX

XQ YQ

YI

YQ

X

The DEMUX functions distribute input symbols sequentially from the top to the bottom output paths.

Fig 44

De-multiplexer Structure for Spreading Rate 3


٩٢

c) MC Mode

DEMUXXI

DEMUXXQ

YI1YI2YI3

YQ1YQ2YQ3

DEMUXX

YI1YI2YI3YQ1YQ2YQ3

b) DS OTD Mode

a) DS Non-OTD Mode

DEMUXXI

YI1

YI2DEMUX

DEMUXXQ

YQ1

YQ2

YI1

YI2

YQ1

YQ2

X

XI YI

DEMUX

XQ YQ

YI

YQ

X

The DEMUX functions distribute input symbols sequentially from the top to the bottom output paths. Fig

45

3.13) Orthogonal Modulation

To reduce or eliminate intra-cell interference, each forward link

physical channel is modulated by a Walsh code. To increase the number

of usable Walsh codes, QPSK modulation is employed prior to spreading.

Every two information bits are mapped into a QPSK symbol. As a result,


٩٣

the available number of Walsh codes is increased by a factor of two

relative to BPSK (pre-spreading) symbols.

Furthermore, the Walsh code length varies to achieve different

information bit rates. The forward link may be interference limited or

Walsh code limited depending on the specific deployment and operating

environment. When a Walsh code limit occurs, additional codes may be

created by multiplying Walsh codes by the masking functions, the codes

created in this way are called Quasi-Orthogonal Functions.

3.13.1) Orthogonal and Quasi-Orthogonal spreading

Walsh functions shall be used with Radio configuration 1 and 2. Walsh

functions or quasi-orthogonal functions shall be used with Radio

configuration 3 through 9.

Each code channel transmitted on the forward CDMA channel shall be

spread with Walsh function or quasi-orthogonal function at a fixed chip

rate of 1.2288 Mcps for spreading rate 1 and 3.6864 Mcps for spreading

rate 3 to provide channelization among all code channels on a given

forward CDMA channel.

One of N-ary (N≤Nmax) time-orthogonal Walsh functions shall be used.

A code channel that is spread using walsh function n from N-ary

orthogonal set (0≤n≤N-1) shall be assigned to code channel number n of

length N. The Walsh function spreading sequence shall repeat with a

period of (N/1.2288) µs for spreading rate 1 and (N/3.6864) µs for


٩٤

spreading rate 3 which is equal; to the duration of one forward traffic

channel modulation symbol.

Quasi-orthogonal functions (QOF`S) shall be created using a none zero

sign multiplier QOF`S mask and a none zero rotate enable Walsh function

as specified in the next two tables. The repeated sequence of an

appropriate Walsh function shall be multiplied by the repeated sequence

of masks with symbols +1 and –1 which correspond to the sign multiplier

QOF mask values of 0 and 1, respectively. The sequence shall also be

multiplied by the repeated sequence of 1’s and j’s (j is the complex

number representing a 90˚ phase shift) which correspond to the rotate

enable Walsh function values of 0 or 1, respectively. The sign multiplier

QOF masks (QOFsign) and the rotate enable Walsh function (Walshrot)

given in the next two tables.

Masking function Function

Binary representation of QOFsign (hex) Walshrot

0 0000000000000000000000000000000

0000000000000000000000000000000

W0256


٩٥

1 7d72141bd7d8beb1727de4eb2728b1be

8d7de414d828b1417d8deb1bd72741b1

W10256

2 7d27e4be82d8e4bed87dbe1bd87d41e4

4eebd7724eeb288d144e7228ebb17228

W213256

3 7822dd8777d2d2774beeee4bbbe11e44

1e44bbe111b4b411d27777d2227887dd

W111256

Masking function Function

Binary representation of QOFsign (hex) Walshrot

0 0000000000000000000000000000000

0000000000000000000000000000000

0000000000000000000000000000000

0000000000000000000000000000000

W0512

1 4bdd442d22b42d44771e78ee1e771187

b422442ddd4b2d4488e178eee1881187

d244ddb444d24b2211781e8887ee881e

d244224b44d2b4dd1178e17787ee77e1

W214512

2 28e4be724172281b28e4be724172281b

1bd78d418dbee4d7e42872be72411b28

824eeb27142782b1824eeb27142782b1

b17dd814d8eb4e7d4e8227eb2714b182

W117512

3 2be7428e172481b2d4e7427117db7eb2

7142e7d44d8124e871bd18d4b2812417

18d471bd2417b281e7d4714224e84d81

4271d4e77eb217db428e2be781b21724

W375512

Code channel number zero shall always be assigned to the forward pilot

channel if the sync. Channel is present; it shall be assigned code W3264


٩٦

when operating in spreading rate 1. If paging channels are present, they

shall be assigned to code channel numbers W164 to W7

64, consecutively.

Other code channels of varying Walsh lengths are usable for auxiliary

pilot channels, common control channels, and forward traffic channels,

provided that they are chosen to be orthogonal or quasi-orthogonal to all

other code channels in use.

When operating in OTD mode, the base station shall use two double-

length Walsh functions or quasi-orthogonal functions in lieu of the single

Walsh function for the forward traffic channels.

3.14) Transmit Diversity

Transmit diversity can reduce the required Ec/Ior (required transmit

power per channel) and thus enhance capacity. Transmit diversity can be

implemented in different ways:

1-Multi-Carrier Transmit Diversity

Antenna diversity can be implemented in a multi-carrier forward link

with no impact on the subscriber terminal, where a subset of the carriers

is transmitted on each antenna. This provides improved frequency

diversity and hence increases forward link capacity. In addition, antennas

can be substantially separated to provide good spatial diversity.

2 -Direct-Spread Transmit Diversity


٩٧

Orthogonal Transmit Diversity (OTD) may be used to provide transmit

diversity for direct spread. The implementation of OTD is as follows.

Coded bits are split into two data streams and are transmitted via separate

antennas. A different orthogonal code is used per antenna for spreading.

This maintains the orthogonality between the two output streams, and

hence self-interference is eliminated in flat fading. Note that by splitting

the coded data into two separate data streams, the effective number of

spreading codes per user is the same as the case without OTD. An

Auxiliary Pilot is introduced for the additional antenna.

Block interleaving

For the Sync channel, Paging channels, and the Forward Traffic

channels, all the symbols after symbol repetition and subsequent

puncturing, if used, shall be block interleaved.

The interleaver parameters m and J are specified in next table.

Multi-frame Interleaving

The base station may support interleaving over 2 or 4 consecutive

frames on the forward Supplemental channel at data rates of 9600 bps or

higher as specified by MULTI- FRAME- LENGTH.

The structure of the n-frame block interleaver (n=2 or 4)is the same as

a single frame interleaver.however,the block size of the interleaver is n


٩٨

times the block size for a single frame. The interleaver parameters for the

n-frame block interleaver are the same as the previous table.

4) Cdma2000 handoff

4.1) Handoff Procedures

Mobile Assisted Soft-Handoff Procedures

The mobile station monitors the Forward Pilot Channel level received

from neighboring base stations and reports to the network those F-PICHs

which cross a given set of thresholds. Those thresholds can be

dynamically adjusted.

Two types of thresholds are used: the first one to report F-PICHs with

sufficient power to be used for coherent demodulation, and the second

one to report F-PICHs whose power has declined to a level where it is not

beneficial to be used for coherent demodulation.

Based on this information, the network orders the mobile station to add

or remove F-PICHs from its Active Set .The same user information

modulated by the appropriate base station code is sent from multiple base

stations. Coherent combining of the different signals from different

sectorized antennas, from different base stations, or from the same

antenna but on different multiple path components is performed in the

mobile station by the usage of Rake receivers. A mobile station will

typically place at least one Rake receiver finger on the signal from each

base station in the Active Set. However, this is not required. If the signal

from the base station is temporarily weak, then the mobile station can

assign the finger to a stronger base station. The signal transmitted by a


٩٩

mobile station is processed by base stations with which the mobile station

is in soft handoff. The received signal from different sectors of a base

station (cell) can be combined in the base station (on a symbol by symbol

basis), and the received signal from different base stations (cells) can be

selected in the infrastructure (on a frame by frame basis).

Soft handoff results in increased coverage range, capacity on the

reverse link (soft handoffs require less mobile transmit power)., fewer

dropped calls and improved clarity.

4.2) Dynamic Soft-Handoff Thresholds

While soft handoff improves overall performance, it has been observed

in the field that it may in some situations negatively impact system

capacity and network resources. On the forward link, excessive handoff

reduces system capacity (more power amplifier resources required) while

on the reverse link, it costs more network resources (backhaul

connections).

Adjusting the handoff thresholds at the base station will not necessarily

solve the problem. Some locations in the cell receive only weak F-PICHs

(requiring a lower threshold) and other locations receive a few strong and

dominant F-PICHs (requiring higher handoff thresholds).

The principle of dynamic threshold for adding F-PICHs (i.e., adding

soft handoff branches to the mobile station) is as follows:

The mobile station detects F-PICHs crossing a given static threshold T1.

The metric for the F-PICH (signal from a given base station) in this case


١٠٠

is the ratio of F-PICH energy per chip to total received power (noted

Ec/Io).

When crossing this threshold the F-PICH is moved to a candidate set. It is

then searched more frequently and tested against a second dynamic

threshold T2. Comparison with this second threshold T2 will determine if

the F-PICH is worth adding to the Active Set (starting to be used for

coherent demodulation). Threshold T2 is a function of the total energy of

the F- PICHs demodulated coherently (in the Active Set).

When F-PICHs in the Active Set are weak, adding an additional F-PICH

(even weak) will improve performance. When there is one or more

dominant F-PICHs, adding an additional weaker F-PICH above T1 will

not improve performance but will utilize more network resources. The

method described above reduces and optimizes the network resources

utilization. Figure 1 graphically shows the difference between a static and

dynamic threshold.

Where SOFT_SLOPE and ADD_INTERCEPT are system parameters to

be adjusted.

When F-PICHs in the Active Set are weak, adding an additional F-PICH

(even weak) will improve performance. When there is one or more

dominant F-PICHs, adding an additional weaker F-PICH above T1 will

not improve performance but will utilize more network resources. The

method described above reduces and optimizes the network resources

utilization. Figure 1 graphically shows the difference between a static and

dynamic threshold.


١٠١

Static and dynamic thresholds

Time graph of soft handoffs during dynamic range.

After detecting an F-PICH above T2, the mobile station will report it

back to the network. The network will then set up the handoff resources

and order the mobile station to coherently demodulate this additional F-

PICH. F-PICHs can be dropped from the Active Set (removing a soft

handoff connection) according to the same principles.


١٠٢

When the F-PICH strength decreases below a dynamic threshold T3,

the handoff connection is removed. The F-PICH is moved back to the

candidate set. The threshold T3 is a function of the total energy of F-

PICHs in the Active Set (similar to T2). F-PICHs not contributing

sufficiently to the total F-PICH energy will be dropped. When further

decreasing below a static threshold T4 a F-PICH is removed from the

Candidate set. An F-PICH dropping below a threshold (e.g., T3 and T4)

is reported back to the network only after being below the threshold for a

specific period. This timer allows for a fluctuating F-PICH not to be

prematurely reported.

Figure 2 shows a time representation of soft handoff and associated

event when the mobile station moves away from a serving base station

(F-PICH 1) towards a new base station (F-PICH 2). Combining static and

dynamic thresholds (versus static thresholds only) results in reduced soft

handoff regions.

The major benefit of this technique is to limit soft handoff to areas and

times when it is most beneficial.

Advantages of CDMA2000

CDMA2000 benefited from the extensive experience acquired through several years of operation of cdmaOne systems. As a result, CDMA2000 is a very efficient and robust technology. Supporting voice and data, the standard was devised and tested in various spectrum bands, including the new IMT-2000 allocations.

There is tremendous demand for new services and operators are looking to provide these to many more subscribers at reasonable prices.

The unique features, benefits, and performance of CDMA2000 make it an excellent technology for high-voice capacity and high-speed packet data. The fact that CDMA2000 1X has the ability to support both voice and data services on the same carrier makes it cost effective for wireless operators.


١٠٣

Due to its optimized radio technology, CDMA2000 enables operators to invest in fewer cell sites and deploy them faster, ultimately allowing the service providers to increase their revenues with faster Return on Investment (ROI). Increased revenues, along with a wider array of services, make CDMA2000 the technology of choice for service providers.

Increased Voice Capacity Voice is the major source of traffic and revenue for wireless operators, but packet data will emerge in coming years as important source of incremental revenue. CDMA2000 delivers the highest voice capacity and packet data throughput using the least amount of spectrum for the lowest cost.

CDMA2000 1X supports 35 traffic channels per sector per RF (26 Erlang/sector/RF) using the EVRC vocoder, which became commercial in 1999.

Voice capacity improvement in the forward link is attributed to faster power control, lower code rates (1/4 rate), and transmit diversity (for single path Rayleigh fading). In the reverse link, capacity improvement is primarily due to coherent reverse link.

Higher Data Throughput Today's commercial CDMA2000 1X networks (phase 1) support a peak data rate of 153.6 kbps. CDMA2000 1xEV-DO, commercial in Korea, enables peak rates of up to 2.4 Mbps and CDMA2000 1xEV-DV will be capable of delivering data of 3.09 Mbps.

Frequency Band Flexibility CDMA2000 can be deployed in all cellular and PCS spectrum. CDMA2000 networks have already been deployed in the 450 MHz, 800 MHz, 1700 MHz, and 1900 MHz bands; deployments in 2100 MHz and other bands are expected in 2004. CDMA2000 can also be implemented in other frequencies such as 900 MHz and 1800 MHz and 2100 MHz. The high spectral efficiency of CDMA2000 permits high traffic deployments in any 1.25 MHz channel of spectrum.

Increased Battery Life CDMA2000 significantly enhances battery performance. Benefits include:

• Quick paging channel operation • Improved reverse link performance


١٠٤

• New common channel structure and operation • Reverse link gated transmission • New MAC states for efficient and ubiquitous idle time operation

Synchronization CDMA2000 is synchronized with the Universal Coordinated Time (UCT). The forward link transmission timing of all CDMA2000 base stations worldwide is synchronized within a few microseconds. Base station synchronization can be achieved through several techniques including self-synchronization, radio beep, or through satellite-based systems such as GPS, Galileo, or GLONASS. Reverse link timing is based on the received timing derived from the first multipath component used by the terminal.

There are several benefits to having all base stations in a network synchronized:

• The common time reference improves acquisition of channels and hand-off procedures since there is no time ambiguity when looking for and adding a new cell in the active set.

• It also enables the system to operate some of the common channels in soft hand-off, which improves the efficiency of the common channel operation.

• Common network time reference allows implementation of very efficient "position location" techniques.

Power Control The basic frame length is 20 ms divided into 16 equal power control groups. In addition, CDMA2000 defines a 5 ms frame structure, essentially to support signaling bursts, as well as 40 and 80 ms frames, which offer additional interleaving depth and diversity gains for data services. Unlike IS-95 where Fast Closed Loop Power Control was applied only to the reverse link, CDMA2000 channels can be power controlled at up to 800 Hz in both the reverse and forward links. The reverse link power control command bits are punctured into the F-FCH or the F-DCCH (explained in later sections) depending on the service configuration. The forward link power control command bits are punctured in the last quarter of the R-PICH power control slot.

In the reverse link, during gated transmission, the power control rate is reduced to 400 or 200 Hz on both links. The reverse link power control sub-channel may also be divided into two independent power control streams, either both at 400 bps, or one at 200 bps and the other at 600 bps. This allows for independent power control of forward link channels.


١٠٥

In addition to the closed loop power control, the power on the reverse link of CDMA2000 is also controlled through an Open Loop Power Control mechanism. This mechanism inverses the slow fading effect due to path loss and shadowing. It also acts as a safety fuse when the fast power control fails. When the forward link is lost, the closed loop reverse link power control is "freewheeling" and the terminal disruptively interferes with neighboring. In such a case, the open loop reduces the terminal output power and limits the impact to the system. Finally the Outer Loop Power drives the closed loop power control to the desired set point based on error statistics that it collects from the forward link or reverse link. Due to the expanded data rate range and various QoS requirements, different users will have different outer loop thresholds; thus, different users will receive different power levels at the base station. In the reverse link, CDMA2000 defines some nominal gain offsets based on various channel frame format and coding schemes. The remaining differences will be corrected by the outer loop itself.

Soft Hand-off Even with dedicated channel operation, the terminal keeps searching for new cells as it moves across the network. In addition to the active set, neighbor set, and remaining set, the terminal also maintains a candidate set.

When a terminal is traveling in a network, the pilot from a new BTS (P2) strength exceeds the minimum threshold TADD for addition in the active set. However, initially its relative contribution to the total received signal strength is not sufficient and the terminal moves P2 to the candidate set. The decision threshold for adding a new pilot to the active set is defined by a linear function of signal strength of the total active set. The network defines the slope and cross point of the function. When strength of P2 is detected to be above the dynamic threshold, the terminal signals this event to the network. The terminal then receives a hand-off direction message from the network requesting the addition of P2 in the active set. The terminal now operates in soft hand-off.

The strength of serving BTS (P1) drops below the active set threshold, meaning P1 contribution to the total received signal strength does not justify the cost of transmitting P1. The terminal starts a hand-off drop timer. The timer expires and the terminal notifies the network that P1 dropped below the threshold. The terminal receives a hand-off message from the network moving P1 from the active set to the candidate set. Then P1 strength drops below TDROP and the terminal starts a hand-off drop timer, which expires after a set time. P1 is then moved from


١٠٦

candidate set to neighbor set. This step-by-step procedure with multiple thresholds and timers ensures that the resource is only used when beneficial to the link and pilots are not constantly added and removed from the various lists, therefore limiting the associated signaling.

In addition to intrasystem, intrafrequency monitoring, the network may direct the terminal to look for base stations on a different frequency or a different system. CDMA2000 provides a framework to the terminal in support of the inter- frequency handover measurements consisting of identity and system parameters to be measured. The terminal performs required measurements as allowed by its hardware capability.

In case of a terminal with dual receiver structure, the measurement can be done in parallel. When a terminal has a single receiver, the channel reception will be interrupted when performing the measurement. In this instance, during the measurement, a certain portion of a frame will be lost. To improve the chance of successful decoding, the terminal is allowed to bias the FL power control loop and boost the RL transmit power before performing the measurement. This method increases the energy per information bit and reduces the risk of losing the link in the interval. Based on measurement reports provided by the terminal, the network then decides whether or not to hand-off a given terminal to a different frequency system. It does not release the resource until it receives confirmation that hand-off was successful or the timer expires. This enables the terminal to come back in case it could not acquire the new frequency or the new system.

Transmit Diversity Transmit diversity consists of de-multiplexing and modulating data into two orthogonal signals, each of them transmitted from a different antenna at the same frequency. The two orthogonal signals are generated using either Orthogonal Transmit Diversity (OTD) or Space-Time Spreading (STS). The receiver reconstructs the original signal using the diversity signals, thus taking advantage of the additional space and/or frequency diversity.

Another transmission option is directive transmission. The base station directs a beam towards a single user or a group of users in a specific location, thus providing space separation in addition to code separation. Depending on the radio environment, transmit diversity techniques may improve the link performance by up to 5 dB.


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Voice and Data Channels The CDMA2000 forward traffic channel structure may include several physical channels:

• The Fundamental Channel (F-FCH) is equivalent to functionality Traffic Channel (TCH) for IS-95. It can support data, voice, or signaling multiplexed with one another at any rate from 750 bps to 14.4 kbps.

• The Supplemental Channel (F-SCH) supports high rate data services. The network may schedule transmission on the F-SCH on a frame-by- frame basis, if desired.

• The Dedicated Control Channel (F-DCCH) is used for signaling or bursty data sessions. This channel allows for sending the signaling information without any impact on the parallel data stream.

The reverse traffic channel structure is similar to the forward traffic channel. It may include R-PICH, a Fundamental Channel (R-FCH), and/or a Dedicated Control Channel (R-DCCH), and one or several Supplemental Channels (R-SCH). Their functionality and encoding structure is the same as for the forward link with data rates ranging from 1 kbps to 1 Mbps (It is important to note that while the standard supports a maximum data rate of 1 Mbps, existing products are supporting a peak data rate of 307 kbps).

Traffic Channel The traffic channel structure and frame format is very flexible. In order to limit the signaling load that would be associated with a full frame format parameter negotiation, CDMA2000 specifies a set of channel configurations. It defines a spreading rate and an associated set of frames for each configuration.

The forward traffic channel always includes either a fundamental channel or a dedicated control channel. The main benefit of this multichannel forward traffic structure is the flexibility to independently set up and tear down new services without any complicated multiplexing reconfiguration or code channel juggling. The structure also allows different hand-off configurations for different channels. For example, the F-DCCH, which carries critical signaling information, may be in soft hand-off, while the associated F-SCH operation could be based on a best cell strategy.

Supplemental Channels One key CDMA2000 1X feature is the ability to support both voice and data services on the same carrier. CDMA2000 operates at up to 16 or 32 times the FCH rate-also referred to as 16x or 32x in Release 0 and A,


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respectively. In contrast to voice calls, the traffic generated by packet data calls is bursty, with small durations of high traffic separated by larger durations of no traffic. It is very inefficient to dedicate a permanent traffic channel to a packet data call. This burstiness impacts the amount of available power to the voice calls, possibly degrading their quality if the system is not engineered correctly. Hence, a key CDMA2000 design issue is assuring that a CDMA channel carrying voice and data calls simultaneously do so with negligible impact to the QoS of both.

Supplemental Channels (SCHs) can be assigned and deassigned at any time by the base station. The SCH has the additional benefit of improved modulation, coding, and power control schemes. This allows a single SCH to provide a data rate of up to 16 FCH in CDMA2000 Release 0 (or 153.6 kbps for Rate Set 1 rates), and up to 32 FCH in CDMA2000 Release A (or 307.2 kbps for Rate Set 1 rates). Note that each sector of a base station may transmit multiple SCHs simultaneously if it has sufficient transmit power and Walsh codes. The CDMA2000 standard limits the number of SCHs a mobile station can support simultaneously to two. This is in addition to the FCH or DCCH, which are set up for the entire duration of the call since they are used to carry signaling and control frames as well as data. Two approaches are possible: individually assigned SCHs, with either finite or infinite assignments, or shared SCHs with infinite assignments.

For bursty and delay-tolerant traffic, assigning a few scheduled fat pipes is preferable to dedicating many thin or slow pipes. The fat-pipe approach exploits variations in the channel conditions of different users to maximize sector throughput. The more sensitive the traffic becomes to delay, such as voice, the more appropriate the dedicated traffic channel approach becomes.

Turbocoding

CDMA2000 provides the option of using either turbo coding or

convolutional coding on the forward and reverse SCHs. Both coding

schemes are optional for the base station and the mobile station, and the

capability of each is communicated through signaling messages prior to

the set up of the call. In addition to peak rate increase and improved rate

granularity, the major improvement to the traffic channel coding in

CDMA2000 is the support of turbo coding at rate 1/2, 1/3, or 1/4. The


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turbo code is based on 1/8 state parallel structure and can only be used for

supplemental channels and frames with more than 360 bits. Turbo coding

provides a very efficient scheme for data transmission and leads to better

link performance and system capacity improvements. In general, turbo

coding provides a performance gain in terms of power savings over

convolutional coding. This gain is a function of the data rate, with higher

data rates generally providing more turbo coding gain.

third generation mobile system (3g): cdma2000

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