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10/24/2009@ .

3 / A .

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C

1. D C 5

2. GE E A C CE F 3G/ / CD A 5

2.1 3 : 5

2.2 5

2.3 3 ? 2 ? 6

2.4 3 2 ? 7

2.5 3 900? 7

2.6 CD A CD A? 7

2.7 3 ? 7

2.8 C 3 8

2.9 ( ) 3 / A 2009? 8

2.10 99 D A 8

3. ECH CA C CE F 3G/ / CD A 9

3.1 F 9

3.2 9

3.3 E / , C 9

3.4 C 10 , C C ? 10

3.5 C 10

3.6 C 11

3.7 F 12

3.8 : ? 13

3.9 & 14

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3.10 C 15

3.11 A 3 17

3.12 ? 18

3.13 3 ? 18

3.14 AB B? 20

4. H D A 20

4.1 D A 21

4.2 D A C 21

4.3 A D A 99 22

4.4 D A? 23

4.5 C ? 24

4.6 D A 25

5. E 25

5.1 E 25

5.2 E C 26

5.3 A E 26

6. H D A & E 27

6.1 D A E 27

6.2 D D A E 28

7. 28

8. CA AC A AGE E 28

9. E E E E A 29

10. E A & E F E E C HA D E 31

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10.1 A 31

10.2 F 32

10.3 C 32

11. HA E AF E H A? 33

11.1 A+ 33

11.2 34

11.3 D C A 34

11.4 C C 35

12. A E D 37

12.1 E C 37

12.2 38

12.3 B 39

12.4 A 39

A & 40

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3 A

1.

This Rough Guide has been written with the objective of aiding those, who already havesome experience with 3G. Prior knowledge will be helpful for deeper understanding ofthe material presented in this guide.

Please note that only WCDMA is considered in this guide and for 2G, only GSM isconsidered. Most of the topics covered are Radio related. Core Network details are notexplained.

2. G C 3G/ / CD A

2.1 3G : G

UMTS Universal Mobile Telecommunications System

Provides mainly Speech, Video, R99 data and HS services

3GPP ReleasesRel 99 3G UMTSRel 5 HSDPARel 6 EULRel 7 HSPA +Rel 8 LTE, All IP network (SAE)Rel 9 SAES Enhancements, WiMax and LTE/UMTS Interoperability

Rel 10 LTE advanced

2.2

.

A (UMTS Terrestrial Radio Access Network ), /ED E C .

.

. .

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Please note that the network below has a common core network for both 3G and 2G.

Fig 1: UMTS/GSM Network

2.3 3G? 2G ?

3G gives much higher data rates compared to 2G. 2G was mainly designed keeping inmind the requirements for Speech traffic. 3G has been developed mainly to cater to dataservices, in addition to Speech traffic. Multiplexing of services with different QOSrequirements on a single connection is possible with 3G.

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2.4 3G 2G?

WCDMA GSMCarrier Bandwidth 5MHz 200kHz

Frequency Re-use Factor 1 1-18Frequency Diversity Multipath diversity with

rake receivers achievedwith 5MHz bandwidth

Frequency Hopping

Packet Data Load based Scheduling Time Slot based Schedulingwith GPRS

Power Control Frequency 1500Hz 2Hz or lower

2.5 3G G 900?GSM900 works at a lower frequency band than 3G, which usually works at the 2GHzband. Lower frequency signals are attenuated less, which gives them greater propagationcapability.

2.6 CD A CD A?WCDMA has a higher bandwidth of 5 MHz compared to IS-95(cdmaOne), which has

only 1.25MHz.

2.7 3G?

FDD Frequency Division Duplexing is mainly used for UMTS. Hence, for uplink anddownlink, we have different frequency bands.

UL Uplink (mobile to base station) 1920-1980 MHz

DL - Downlink (base station to mobile) 2110-2170 MHz

Point to remember: Generally, operators are given 5MHz Carriers and can have one ormore carriers depending on the operator requirements as well as frequency bandavailability.

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2.8 C 3G

CSIB Conversational, Streaming, Interactive, Background

TrafficClass

Conversational(Real Time)

Streaming(Real Time)

Interactive(Best Effort)

Background(Best Effort)

BasicFeatures

- Preserve timerelation (variation)

betweeninformation

entities of thestream

- Preservetime relation(variation)between

informationentities of the

stream

- Requestresponse pattern

-Destination is notexpecting the data

within a certain time

- Conversationalpattern (stringentand low delay )

-Preserve payloadcontent

-Preserve payloadcontent

Example ofthe

application

voice streamingvideo

web browsing emails

2.9 ( ) 3G/H A 2009?

ServiceCS12 Speech Service with 12.2 kbps dedicated channelCS64 Video Telephony with 64kbps dedicated channelPS64 - Packet Switching with 64kbps dedicated channelPS128 Packet Switching with 128kbps dedicated channelPS384 Packet Switching with 384kbps dedicated channelHSDPA - High Speed Downlink Packet Access shared channelEUL Enhanced Uplink

2.10 99 H D A

- R99 Packet service requires dedicated channels whereas HSDPA users have ashared channel

- Speeds of HSDPA are much higher compared to 3G(R99). In real networks, anaverage HS subscriber gets around 5-8 times throughput, compared to an R99data user. We can easily say that an average HS user can get between 1100kbpsto 2000kbps..whereas an average R99 user can get around 250- 280kbps.

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Ofcourse, all these values depend on the configuration of the network. Forexample speeds of about 6Mbps was reported during random field tests in one of

the networks in Kuwait. Introduction of higher capacity UEs as well as highermodulation schemes will further increase the HS throughputs.

3. C 3G/ / CD A

3.1 F CD A ,

. ( ) . A .

.

3.2 .

. , .

: 27 33 B . 27 30 B .

3.3 E / , CE / .

, ( ) .

: A E / = 8 B 8 B

.

:

3 . E 1/ , E 2/ E 3/ .

.

C : C , .

Ec/No = RSCP/RSSI

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3.4 C

What is the difference between

Spreading Code = Channe

Usage

LengthNo: of Codes

Fig 2: Usage of Scrambli

3.5 C

Downlink Scrambling C

3 types of scrambling cDownlink primary scramcode, is allocated for eacscrambling codes can be u

10

Scrambling, Spreading and Channelization Codes?

lization Code

Channelization Code/Spreading Code

Scr

DL Separation of DLdedicated user channelsUL Separation of Dataand Control channels fromthe same terminal

DL Sep(Sectors)UL Sep

Variable FixedDepends on SF DL 51

UL Un

g Codes and Channelization codes

des

des are available in DL: primary, secondaling codes are used for cell separation. Oneh cell. Secondary scrambling codes are nosed in compressed mode.

mbling Code

aration of Cells

aration of UEs

limited (Millions)

ry and alternative.rimary scramblingused. Alternative

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Uplink Scrambling Codes

2 types of scrambling codes are available in UL : long and short. Only the long ones areused. Uplink scrambling codes are used for separating the different UEs in the same cell.RNC allocates the code.

3.6 C

Downlink Spreading Codes (Channelization Codes)

DL spreading codes differentiate the dedicated user connections/channels within one cell.Ideally they are orthogonal to each other, though due to multipath propagation, someorthogonality might be lost.

Channelization codes are managed with the help of a code-tree. Basic rule is that codesare orthogonal, if they do not descend from an already used code. If a code is used, thenall the codes below and above on the same branch are unavailable for service. Resourcemanager keeps track of the codes allocated so that orthogonality of the code tree ispreserved.

Fig 3: Code Tree for orthogonally spreading codes

Example : Code management with the help of the code tree

If code C2(0) in the Tree of orthogonal spreading codes (in the figure above) is allocated,then:

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All codes below it in the same branch become unavailable, starting with C3(0) and C3(1),then, on the next level, C4(0), C4(1), C4(2) and C4(4), and so on.

All codes above it in the same branch to root become unavailable, that is, C1(0) andC0(0) cannot be assigned to any user .

Spreading codes of some channels (mainly Pilot and P-CCPCH) are fixed. Spreadingcodes for all other downlink physical channels are allocated by the resource manager.

3.7 F

Higher the bit rate of the data service, lesser the spreading factor.

Service Spreading FactorHalf Rate AMR 256

Speech 128CS64 32PS64 32

PS128 16PS384 8

HSDPA 16Table giving DL spreading factors for different services

Points to remember :

Usually UL spreading factor for a service is half the value of that in the DL (when theRAB bearer rates are the same in both UL and DL).

For example: DL SF for speech(AMR12.2) service is 128, where as in UL, it has a SF of64.

Why should we avoid pulsed transmission in the UL?

During the silent periods, only information for link maintenance purposes are needed inUL direction. A typical example is Power Control commands at 1.5KHz which caninterfere with the telephony voice frequency band.

To avoid audible interference to audio devices in UL, data and control channels are nottime multiplexed in WCDMA. Continuous transmission is achieved with I/Q codemultiplexing or by using parallel control and data channels.

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3.8 G : ?

In WCDMA, the baseband signal is spread using a spreading code

By spreading,

1) Baseband signal is spread over the entire spectrum (3.84MHz), with help of aspreading code

2) Overall noise floor rises, but the baseband signal is hidden below the noise floorand hence difficult to detect

3) Effect of Narrow-band interference is reduced, since only a small part of thesignal will be affected and data can be recovered with effective techniques

4) Effect of Multipath fading is also reduced5) Higher the bit rate of the service, lower the SF (Speech SF = 128, PS384 SF= 8)

and lower the processing gain

Despreading is done at the RX side.

By despreading

1) We get the baseband signal back and gain from the processing gain.

Point to remember : Spreading and despreading can be considered as a process of

pushing the actual baseband signal below the noise floor and then retrieving it.

Processing Gain = 10 log (chiprate / bit rate)

To get a good service, the requirement is

Rx Sig Level + Processing Gain > Eb/No

Eg: PG for speech = 10 log ( 3.48Mcps / 12.2Mbps) = 25dB

Eb/No requirement for speech = 5dB (for good service)

Rx sig level = 5 25 = -20dB (which implies that even if the received signal is 20 dBbelow the noise floor, the WCDMA receiver can detect the speech signal).

In GSM, the C/I requirement is about 9-12dB. This directly gives an advantage of about20-25 dB for WCDMA.

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3.9 & H

Soft handover is the condition in which the UE is connected to more than one NodeB atthe same time. While in connected mode, UE continuously measures the neighbouringsignals and compares the measurement results with specific handover thresholds set bythe operator. When the threshold is exceeded, UE sends a measurement report to theRNC. RNC decides if the SHO should take place.

Soft Handover is also called MEHO Mobile Evaluated Handover

Active Set : Set of cells which are in soft handover.

There are 3 types of Soft Handover

1) Handover between sectors in the same site (Softer Handover)2) Intra-RNC SHO3) Inter-RNC SHO

Majority of Soft handovers are usually Intra-RNC SHO.

Advantages of SHO:

1) Seamless handover without disconnection of RAB2) Macro diversity gain..achieved in both UL and DL due to the combining of

signals from different cells3) Better performance in areas where a single cell is not strong enough

Disadvantages of SHO

1) Increased consumption of radio resource as one UE in SHO, will use more thanone radio link at a time

Point to remember : SHO is kept in mind during the initial planning and ideally anoverhead of 30-40% is assumed.

Events

Mobile sends Measurement Report to RNC, when certain thresholds are crossed. ForSHO, it is important to know Event 1a, 1b, 1c and 1d.

E 1 : A

Event 1b: deletion of a cell from the Active Set

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Event 1c: replacement of weaker cell in Active Set by another stronger cell (not in theActive Set)

Event 1d : replacement of best cell in Active Set by a stronger cell (from Active Set,Monitored Set or Detected Set)

3.10 C

Main purpose of Power control mechanism is to

1) maintain the quality of service2) minimize the transmitted power in both UL and DL

In WCDMA, downlink transmitted power determines the interference and hence the airinterface capacity. So it is important to avoid excessive transmission in DL.

A single UE can create problems with excessive transmission in the UL. Power controlmechanism takes care of this.

Power control is done on both common and dedicated channels. Power control incommon channels ensure that sufficient coverage is available to setup UE-originating and

UE-terminating calls as well as data transfer on RACH and FACH. Power control indedicated channels ensure that connection quality is maintained in terms of BLER (BlockError Rate)

There are mainly 3 types of power control.

1) Open loop power control2) Closed loop power control (Fast Power Control)3) Outer loop power control

C When the UE accesses the system it first sends a preambleand waits for a response from the NodeB. If this expected response, AI (AcquisitionIndicator), is not obtained, the UE transmits another preamble with slightly higher power.The process of ramping up preamble power continues till either a response is obtainedfrom the NodeB or the allowed number of preamble steps are used. When the maximumnumber of steps in a preamble cycle is used, another preamble cycle is started, which inturn is limited by a maximum number of preamble cycles set by the operator.

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Point to remember : Three parameters are controlled by the operator in the case ofOpen loop power control ( preamble step, number of preamble steps in a preamble cycle

and the number of preamble cycles).

C C (Fast Power Control) setting of TX power based on SIRtarget (in NodeB). Done with a frequency of 1500Hz.

UE and BTS continuously compare the actual SIR of the received signal with a targetSIR. Based on the comparison, BTS/UE tells the UE/BTS to either increase or decreasethe transmission power.

C setting of SIR target based on Frame quality (in RNC).

Outer loop power control aims to provide the required quality in both UL and DL, bymonitoring the BLER of the received signal. Based on the BLER, the SIR target for theFast Power Control is increased or decreased.

For example: if the received BLER is not meeting the expected quality, then the SIRtarget is increased and if the received BLER is higher than the expected quality, then theSIR target is decreased.

Fig 4: Power Control Mechanism

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3.11 A 3G

How do we get the speed of 2Mbps for R99 ?

Data Rate = Chip Rate / Spreading Factor

In R99, 3 codes with SF4 gives the max possible data rate.

Data Rate for one SF4 code = (3.84Mcps / 4 ) = 960ksps

ksps = kilo symbols per second

Since R99 uses only QPSK, 1 symbol = 2 bits

Hence, Data Rate = 480ksps = 960 * 2 bits = 1920kbps = 1.92Mbps

For 3 SF4 codes, data rate = 3 * 1.92Mbps = 5.76 Mbps

BUT, Data Rate = Net User Data + Channel Code Redundancy + Control Data

After taking out Channel Code Redundancy and Control data, Net User Data == 2Mbps

(the above value is for one sector with one carrier)

Point to remember : The code rate used in R99 is 1/3

Why do we have 384kbps as the max possible data for a single R99 Packet user in3G?

Currently PS384 is the highest RAB available in DL for R99 Packet users.

SF for PS384 = 8

Data Rate for one SF4 code = (3.84Mcps / 8 ) = 480ksps

ksps = kilo symbols per second

Since R99 uses only QPSK, 1 symbol = 2 bitsHence, Data Rate = 480ksps = 480 * 2 bits = 960kbps

BUT, Data Rate = Net User Data + Channel Code Redundancy + Control Data

After taking out Channel Code Redundancy and Control data,

Net User Data == 384kbps (max possible)

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How do you calculate maximum possible speed in HSDPA?

Using the formula (data rate = chiprate/spreading factor),

1 QPSK code at SF16 = 480kbps

1 16-QAM code at SF16 = 960kbps

1 64-QAM code at SF16 = 1440kbps

For HSDPA after applying coding rate

1QPSK Code = 360kbps

1 16-QAM Code = 720kbps

1 64-QAM Code = 1080kbps

10 codes with 16QAM = 720 * 10 = 7200 kbps = 7.2Mbps

15 codes with 16QAM = 720 *15 = 10.8Mbps (max per cell or sector)

15 codes with 64QAM = 1080 *15 = 16.2Mbps (max per cell or sector)

Theoretical max of HSDPA with one carrier = 15 Codes * 1440kbps = 21.6Mbps for asingle carrier (assuming coding rate of 1, which is impossible in actual conditions)

3.12 ?

- User position in the cell- Interference from other users and neighbouring cells- Number of subscribers accessing the same cell- Speed of the customer (if he is mobile)

3.13 3G ?

Pilot Pollution (Improper Pilot Power Planning)

Main objective of Pilot planning is to have a dominant signal at a given place. Inpractice, this is difficult to achieve. 2 to 3 strong signals are still ok, since Soft handoverwill manage the situation. But if you have more signals coming at the same place withmore-or-less equal strength, then the UE gets confused and cannot correctly decode the

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signals due to low Useful Signal-to-Interference ratio (Ec/No) and hence the call getsdropped.

Points to remember:

- Strive to have ONE dominant Pilot signal at a given place.- In Ec/No, Ec is good (as long as there is no pilot pollution). No is interference.

Power, Tilt and Azimuths optimization mainly used to avoid pilot pollution.

Missing Neighbour Definitions

This can be observed on Field with Tems or any monitoring tool (as Detected Set).When the UE is getting a strong signal which is not defined as a neighbour to the existingcells in the Active Set, the new signal adds to the interference. Soft handover does nottake place and as a result Ec/No degrades. As a result the call drops when the new signalis about 15dB higher than the cells in the Active set.

Improper UEs

Though not observed on a wide scale, this can be a problem. A malfunctioning UE cancause many problems like

- Demanding too much power from the base station- In-efficient channel switching- Excessive transmission of power in UL

IRAT HO Parameter Definition

- Improper definitions can lead to un-necessary handover between 3G and 2g. Thiscan be a problem especially for indoor customers using HSDPA or data services.Overall throughput of the data user will be affected due to unnecessaryhandovers/cell changes.

Cell Breathing

With more and more users coming into a cell, the actual power available for services islesser than the power available in an empty cell. So the overall coverage of the cellshrinks.

Cell breathing is more of a planning issue and has to be considered at the planning stageitself. Proper handover regions should be planned, to avoid any coverage gaps.

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Prioritizing Neighbours

More efficient handover can be achieved by proper prioritization of neighbours. It ispossible to give higher priority for some cells than to other cells, so as to make sure thatchances for a handover is higher between certain cells. This parameter can also be used toavoid handover in certain locations between certain cells to some extent. Improperallocation of priority can lead to bad handover decisions.

Low Sites

One major mistake RF planners did in the beginning was to install low sites for UMTS,thinking mistakenly that since interference is to be avoided in UMTS, it is better to havelow sites with lower coverage areas.

In actual practice, low sites are generally problematic as they overshoot and contribute toPilot Pollution. Down-tilting of low sites can lead to coverage holes(we should keep inmind that down-tilting is an efficient way of reducing overshooting).

3.14 AB B?RAB Radio Access Bearer Link between UE and Core (Radio + Iub + Iu)

RB Radio Bearer Link between UE and RNC (Radio + Iub)

4. H D A

HSDPA has a fixed spreading factor of 16. Multiple codes can be reserved for HSDPA atthis SF level and depending on the number of codes available, the speed varies. Detailsare given in the section What is the maximum possible speed in HSDPA?

Generally operators reserve 5 or 10 codes per carrier (out of the 15 available) for HSDPAservice, which implies that these codes are not available for other R99 services likeSpeech, CS64 and PS. There are different ways of code allocation for HSDPA, and thisvaries from vendor to vendor.

When there is a shortage of codes, due to higher traffic, the operators can go for a secondcarrier. Operator can decide how to distribute HS and R99 traffic in different carriers. Itis also possible to have a carrier fully allocated to HS, which implies that 15 codes will beavailable solely for HS and no other services will be possible in that carrier.

Point to remember: Greater the number of codes you reserve for HS, lesser theresources available for R99 services.

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4.1 H D A

- Shared Channel Transmission (enabling one user to have more than one code)- Shorter TTI (2ms)- Higher Modulation Technique (16QAM )- Hybrid ARQ Retransmission- Faster Scheduling based on Radio conditions- Better Scheduling Techniques(code rate, modulation technique)

4.2 H D A C

In addition to the new downlink shared channel HS-DSCH, some control channels arealso required for HSDPA. Mainly they are HS-SCCH and HS-DPCCH.

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Channel Direction ContentHS DSCH DL User Data

HS-SCCH DL

Control information to address UEs andinformation for decoding the transport block.UEs can see upto 4 HS-SCCH

HS-DPCCH UL ACK/NAK, CQI

A-DCH UL and DLSRB (Control signaling: RRC and NAS) in DLSRB and User data in UL

D A C 99 C

4.3 A H D A 99

- Faster Retransmission (due to control in NodeB), leading to much lower RTT

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Fig 7: Retransmission methods in R99 and HSDPA

As seen in the picture above, in case of R99, retransmission decision is taken in the RNC(RLC layer), whereas in HSDPA, the retransmission decision is taken in NodeB (MAC-hs layer). This leads to a great reduction in overall RTT (Round Trip Time)

- More codes used by a single user, hence higher throughputs- Shorter TTIs, hence better response time and RTT- 16QAM is not used in R99- Soft Combining of re-transmission

Point to remember : There are mainly 2 types of scheduling in HSDPA Round Robinand Proportional Fair. Round Robin scheduling, allocates resources to every user in around robin manner regardless of the radio conditions, the users are in.

Proportional fair scheduling takes into account, the radio conditions also and tries toimprove the overall cell throughput by giving slightly higher preference to users in betterradio conditions.

In actual testing conditions, not much difference in overall cell throughput was observedbetween the two scheduling techniques and since Round Robin scheduling came free ofcharge, with most vendors, it was the preferred scheduler.

4.4 H D A?

C 3.11

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4.5 C ?

CQI is the feedback which the system receives from the UE and it mainly indicates theradio condition of the UE. Depending on the CQI values, NodeB scheduler allocatesresources to the UE.

Higher the CQI, better the network. An average CQI value of about 22 and above,indicates a reasonably good network. CQI values less than 17, indicates a low qualitynetwork and optimization is required.

Fig 8: Overall picture of how radio conditions affect HS Throughput and Power

Requirement

The figure above summarizes the tests conducted for a HS user in both bad and goodradio conditions.

In all the 3 graphs above, the left side represents a user in bad radio condition and theright side represents a user in a good radio condition .

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A user in a very bad radio condition reports an average CQI of 14, whereas the same userin excellent radio conditions reported an average CQI of 26. In bad radio conditions, the

user consumed much more power, though he got almost the same throughput as the userin good radio condition.

Points to remember :

- It is very important to have a HS user in good radio conditions, since higherthroughputs can be achieved with lesser transmitted power, leading to increasedcapacity for the system.

- For higher order modulations to work, CQI values should be high.

4.6 H D AChannelization Codes, Modulation Scheme, Channel Elements, Power, Simultaneoususers, UE Category

5. E

E C 1.4 2 E

384 99. , E 99.

F : A 4 ( ,)

E , 32 .

99, 384 AB , CE = 4 * 16= 64 CE , 384 AB 16 CE . , 32 CE

E .

5.1 E

- Hybrid ARQ with Soft Combining

- Fast Channel Dependent Scheduling

- Multi-code Transmission

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- Power Control

- Soft Handover

5.2 E C

5.3 A E

Case 1: Assuming that the UE category available can support only upto 2 SF4,

Data rate per channel = 3.84/4 = 0.96Msps

1symbol = 1bit since BPSK is used in EUL

So, Data rate per channel = 0.96Mbps

Since 2 channels (2 SF4) are possible, maximum rate = 0.96 * 2 = 1.92Mbps

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After taking out all FEC, CRC, MAC-headers and L3 signaling, data rate at RLC level =1.376Mbps

Data rate at L1 (transport block level) = 1.46Mbps

Point to remember: Above figure is the total bit rate achievable with EUL in one cell,when the maximum possible configuration is 2 * SF4 channels (and only BPSK isavailable). If we have SF2 available, we will be getting higher UL throughputs.

Case 2: Assuming that the maximum channel capacity of 2SF2 + 2SF4 is available,

Data rate per SF2 channel = 3.84/2 = 1.92Mbps

Data rate per SF4 channel = 3.84/4 = 0.96Mbps

Total data rate = (2*1.92) + (2*0.96) = 5.76Mbps

Realistically with coding Max EUL Data Rate = 5.76 * = 4.32Mbps

Why is it NOT beneficial to have 16-QAM in EUL ?

Since UL is interference limited:

- It is better not to have power-inefficient higher-order modulation schemes

- Cost effective design of UE power amplifier is possible with lower-ordermodulation schemes, since they have lesser PAR (Peak to Average Ratio) whichin turn lead to lesser Electromagnetic Interference (EMI) generated by the UE.

6. H D A & E

6.1 H D A E

In HSDPA, the shared resource is DL Transmission Power, Channelization Codes andChannel Elements

In EUL, the shared resource is UL interference and Channel Elements

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6.2 D H D A E

HSDPA EULSpreading Factor Fixed = 16 Variable from 256-2Soft Handover No (only A-DCH in SHO) YesPower Control No (Check RPA ) YesModulation Scheme 16QAM & QPSK BPSKLink Adaptation Rate Control Rate & Power Control

7.

Accessibility both RRC and RAB phases considered

Mobility Soft/softer handover (30-40%), IRAT handover

Retainability Mainly Voice and HS drops. Currently the practice is to monitorMinutes/Drop

Traffic Erlangs for Speech/CS64 services, Data Volume for PS/HS services

Integrity CQI for HS, BLER for R99 (if needed)

8. C

Main purpose of capacity management is to provide sufficient QOS and coverage forusers. Admission Control and Congestion Control are the two main mechanisms usedfor capacity management.

Admission Control ensures that a new user will be connected only if there are enoughresources available for him.

Congestion Control tries to keep the usage of the system within reasonable limits. Forexample, if there are 3 PS384 users in a cell and one of them moves into a bad signalarea and requires more power to maintain the data rate, the system checks the used DLtransmitted power. If it has crossed a threshold, the user is downgraded from PS384 toPS128 or to PS64, depending on the available power. By doing this, channel element

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- RNC: Total Traffic, Simultaneous number of HS users, ATM connectivity, totalnumber of NodeBs which can be connected to one RNC

- NodeB: Channel Elements, Code Tree, DL Transmit Power

Channel Elements are one of the major hardware resource in NodeB to be plannedand monitored carefully. Different services have different requirement of CEs. Inmost of the vendors, there is a fixed allocation of CEs for HS services. R99services use CE when required. The tables below give sample CE requirementsfor different services. HS requirements are not included in these tables, as theyare different for different vendors.

SpreadingFactor Bearer Data Rate (kbps) Channel Element Requirement

128 AMR 12.2 1

32

32 64 2

16 128 4

8 384 8Sample Table for DL Channel Element Requirement

Spreading Factor Bearer Data Rate (kbps) Channel Element Requirement

64 AMR 12.2 1

32 32 2

16 64 4

8 128 8

4 384 16Sample Table for UL Channel Element RequirementChannelization Codes : With the introduction of HSPA, channelization codeshave become a major limiting factor in terms of resource utilization. Since atleast5 to 10 codes are reserved for HS, only the remaining codes are available for R99services like Speech, CS64 and R99 Packet. Generally, vendors go for a secondcarrier in case of code congestion.

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DL Transmit Power : In WCDMA, downlink is power limited , assuming that wehave enough resources like CEs and channelization codes. Hence it is important

to monitor the DL power consumption. We can say that Power == Capacity. Wehave to keep in mind that Packet users require more power compared to Speechusers.

Point to remember : Channel Element is a NodeB level resource. Channelizationcode is a cell level resource.

- Iub: Proper planning should be done for VP/VC. Different methods areavailable. One of the main limitations if you have AAL2 switching is the numberof CIDs available per VC.

For example: If you have one STM1 link with 155Mbps, you can divide it intoany number of VCs as you need.

Case 1: If you assign just one VC, you have a total of 248 CIDs availableCase 2: If you assign 10 VCs, you have 248 * 10 = 2480 CIDs available.

Assuming only voice users in the network, since each Voice user needs 2 CIDs,Total possible subscribers in case 1 = 248 / 2 = 124 speech usersTotal possible subscribers in case 2 = 2480 / 2 = 1240 speech users

So in case1, even when there was more than enough capacity (155Mbps), we havea limitation of 128 speech users due to the definition of VC.In case2, with the same capacity available as in Case1, we have 10 times morespeech users.

Please keep in mind that the each HS user require 3 CIDs. Further, separate CIDsare needed for Control purpose also.

10. A & F H10.1 A H ( 3 )

Required since 3G coverage is generally less compared to 2G.

It is important to have proper parameters defined for Inter-RAT handovers (mainlyUMTS-GSM).

Event 2d occurs when the 3G measured quality is below a certain threshold for a certainperiod of time and this triggers measurement on IRAT or Inter-Frequency (depending on

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vendor). Compressed mode measurements on 2G start after event 2d. Once event 2d istriggered, if the measured quality of 2G is above a certain threshold for a certain period

of time, then event3a occurs. Actual 3G-2G handover is triggered by event 3a.10.2 F H ( 2 )

Required when 2 or more frequencies are implemented in a network.

Event 2d occurs when the measured quality is below a certain threshold for a certainperiod of time and this triggers measurement on IRAT or Inter-Frequency (depending onvendor). Compressed mode measurements on the 2 nd frequency start after event 2d.Onceevent 2d is triggered, if the measured quality of the 2 nd frequency is above a certainthreshold for a certain period of time, then event2b occurs. Actual IF HO is triggered by

event 2b.

Point to remember :

- Event 3a : 3G-2G HO- Event 2b : Inter-Frequency HO

Event 2f occurs when the measured quality is above a certain threshold for a certainperiod of time and this triggers the stopping of IRAT/Inter-Frequency measurements.

Depending on the settings, when event 2d occurs, the system decides if IRAT or IF handover should take place . In some vendors both are possible.

For example: In Ericsson you have to set either IRAT or IF HO, where as in Nokia it ispossible to have IRAT and IF handovers from the same carrier.

Event 6d occurs when the UL UE Tx power exceeds a certain threshold for a certainperiod of time. Event 3a (IRAT HO) or Event 2b(IF HO) follows.

Event6b, occurs when the UL UE Tx power is below a certain threshold for a certainperiod of time. All ongoing HO attempts are aborted if DL Quality for both Ec/No andRSCP are good.

10.3 C

Compressed mode mechanism enables the UE to carry out measurements on anotherfrequency. Certain idle periods are created in radio frames during which the UE canperform measurements on other frequencies. No user data is lost as it is compressed inthe time domain using one of the below 2 methods

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- Enhanced Cell_FACH- Voice Over HSPA

Below sections will give you a brief idea of some of these features.

11.2

Multiple Input Multiple Output involves using multiple antennas at both transmit andreceive side which leads to significant increase in achievable throughputs, without thenecessity for additional bandwidth or transmit power.

Point to remember:

HSPA+ Rel: 7 (MIMO) can theoretically support up to 28Mbps with a single 5MHzCarrier

HSPA+ Rel: 8 (Higher Order Modulation + MIMO) can theoretically support up to42Mbps with a single 5MHz carrier

11.3 D C H A (also known as Dual Cell HSPA)

DC - HSPA aims to increase the available user data rates by merging 2 carriers of 5MHzeach, thus making available up to 10MHz carrier bandwidth for a user.

Higher Bandwidth available to a user = = Higher Throughput for the user

Basic idea of DC-HSPA is to achieve better resource utilization by means of jointresource allocation and load balancing across the carriers.

Some of the features for DC-HSPA are

- New MAC entity, MAC-ehs which supports HS-DSCH transmission/reception inmore than one cell served by the same Node-B

- New UE categories required (Categories 21 to 24)- Anchor Carrier : Carrier with all physical channels (as shown below)- Supplementary Carrier: Carrier with just HS-PDSCH and HS-SCCH

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Table giving UE categories for EUL

12.2

Fig : Constellation diagrams of different modulation schemes

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12.3 B

System information is broadcast regularly to the UE on the BCCH. It containsparameters related to Cell Selection, Reselection, Location and routing registration,Handover, Power Control etc. Any parameter change in the system information isnotified to all UEs in the cell by a paging message or by a system information changeindication message. The table below list the different SIB messages available.

12.4 A

RRC : Radio Resource Control

- Handles control plane signaling of Layer3 signaling between UEs and RNC

NBAP : NodeB Application Protocol (Iub)

- Signaling protocol responsible for the control of NodeB by RNC- NBAP has two parts: C-NBAP and D-NBAP

C-NBAP (Common NBAP) controls the overall functionality of the NodeB

B C

B , B B1 B

B1 , C , A

A B2 A B3 C B4 C . C

B5 B5 , C B7

B11 , C

B12 B18 B11.

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D-NBAP (Dedicated NBAP) controls radio links specific to UEs

RANAP : Radio Access Network Application Part (Iu)

- For signaling between Core Network( MSC or SGSN) and RNC

RNSAP : Radio Network System Application Part (Iur)

- Signaling protocol responsible for communication between RNCs

A &

I would like to thank my colleagues at Wataniya Telecom, Kuwait as well as Mobitel,Slovenia for the support extended to me. I would like to thank specially,

- Naveen Krishnapillai, Wataniya Telecom, Kuwait- Amol Rajan Pradhan , Wataniya Telecom, Kuwait- Santosh Tummala , Wataniya Telecom, Kuwait- Amin Sudhir Vasanth , Wataniya Telecom, Kuwait- Iztok Saje, Mobitel, Slovenia

Material for this guide has been compiled from

- Authors experience in 3G from year 2002 with Mobitel, Slovenia and WataniyaTelecom, Kuwait

- WCDMA for UMTS by Harri Holma and Antti Toskala- Internet (especially Wikepedia)- White Paper Dual Cell HSDPA and its Future Evolution - Nomor Research

GmbH- Articles from different vendors, especially Ericsson and NSN