zxc 10 bts

Technical Description Of ZXC10-BTS

ZTE Confidential Proprietary

Technical Description of ZXC10-BTS

About the Document:

Version Status Date Author Approved By Remarks

V1.0 Confidential 2003-12-12 CDMA Technical

Team, ZTE

V1.1 Confidential 2004－6-07 CDMA Technical

Team, ZTE

V1.2 Confidential 2004－7-20 CDMA Technical

Team, ZTE

Copyright Notice:

Copyright © 2004 ZTE Corporation Shenzhen P. R. China

All rights reserved. No part of this documentation may be excerpted, reproduced, translated,

annotated or duplicated, in any form or by any means without the prior written permission of ZTE

Corporation.


I

Table of Contents

1 BTS Overview............................................................................................................................... 1 1.1 Position of BTS in the CDMA System............................................................................... 1 1.2 Basic Functions................................................................................................................... 1 1.3 System Features .................................................................................................................. 2 1.4 Standards Complied ............................................................................................................ 2

2 Technical Indices .......................................................................................................................... 4 2.1 System Operating Environment Indices ............................................................................. 4 2.2 Performance Indices............................................................................................................ 7

3 BTS Hardware............................................................................................................................ 12

3.1 Overview........................................................................................................................... 12 3.2 EBDS_HS Subsystem....................................................................................................... 13 3.3 EBDS_IP Subsystem ........................................................................................................ 17 3.4 RFS ................................................................................................................................... 21 3.5 TFS.................................................................................................................................... 29 3.6 PS...................................................................................................................................... 32 3.7 LFM in the Transmission Subsystem................................................................................ 34

4 BTS Software .............................................................................................................................. 35 4.1 Overview........................................................................................................................... 35 4.2 CCM Software .................................................................................................................. 36 4.3 TRX Software ................................................................................................................... 39 4.4 CHM Software .................................................................................................................. 40 4.5 TRX Software ................................................................................................................... 41

5 Networking & Configuration .................................................................................................... 43 5.1 BTS Networking ............................................................................................................... 43 5.2 BTS Configuration............................................................................................................ 44

Appendix a: Abbreviation ................................................................................................................. 50


II

Figures and Tables

Figures Fig. 1 ZXC10-BTS in BSS.............................................................................................. 1 Fig. 2 Profile of the ZXC10-BTS................................................................................... 5 Fig. 3 Logical Structure of the BTS .............................................................................. 12 Fig. 4 Working Principles of the BTS........................................................................... 13 Fig. 5 HIRS_ BDS Architecture.................................................................................... 14 Fig. 6 Slot Layout of the EBDS_HS Shelf.................................................................... 15 Fig. 7 EBDS_IP Position Schematic Diagram .............................................................. 18 Fig. 8 Working Principles of the 1-Carrier 3-Sector RFS............................................. 22 Fig. 9 Working Principles of the 2-Carrier 3-Sector RFS............................................. 23 Fig. 10 Working Principles of the 4-Carrier 1-Sector RFS........................................... 24 Fig. 11 TRX Shelf ......................................................................................................... 25 Fig. 12 HPA Shelf ......................................................................................................... 25 Fig. 13 RFE Shelf.......................................................................................................... 25 Fig. 14 Working Principles of the TRX ........................................................................ 26 Fig. 15 Working Principles of the DUP ........................................................................ 27 Fig. 16 Working Principles of the COM....................................................................... 28 Fig. 17 Working Principles of the TFS ......................................................................... 29 Fig. 18 Slot Layout of the TFS in the TRX Shelf ......................................................... 30 Fig. 19 Working Principles of the PS............................................................................ 33 Fig. 20 PS Shelf............................................................................................................. 33 Fig. 21 ZXC10-BSS Software Composition ................................................................. 35 Fig. 22 Structure of the Foreground EBDS................................................................... 37 Fig. 23 Connections Between RCM and Other Modules.............................................. 38 Fig. 24 Software Modules of the CES........................................................................... 41 Fig. 25 Star Networking................................................................................................ 43 Fig. 26 Chain Networking............................................................................................. 44 Fig. 27 Hybrid Networking ........................................................................................... 44 Fig. 28 Extended mode of RF part ................................................................................ 44 Fig. 29 Single-carrier Configuration of One BTS Rack................................................ 45 Fig. 30 Dual-Carrier Configuration of One BTS Rack ................................................. 46 Fig. 31 Cells of a Mobile Network................................................................................ 47 Fig. 32 Two Site Types ................................................................................................. 47


III

Tables Table 1 Weight of the ZXC10-BTS ................................................................................ 6 Table 2 DC Power Supply Indices of the ZXC10-BTS .................................................. 6 Table 3 Power Consumption of the ZXC10-BTS .......................................................... 6 Table 4 Performance of 800M/450M TX ....................................................................... 7 Table 5 Performance of 800M/450M RX ....................................................................... 8 Table 6 Performance of 1.9G/2.1G TX........................................................................... 9 Table 7 Performance of 1.9G/2.1G RX......................................................................... 10 Table 8 Outband Suppression ....................................................................................... 10 Table 9 Types of DSM.................................................................................................. 19 Table 10 Recommended Site Types and Number of Traffic Channels......................... 47 Table 11 Site Types and Number of Boards ................................................................. 48 Table 12 Abbreviation in this document ....................................................................... 50

ZTE Confidential Proprietary 1

1 BTS OVERVIEW

1.1 Position of BTS in the CDMA System The position of the ZXC10-BTS in the Base Station Subsystem (BSS) is shown below.

MSC

PDSN

Um interfaceMS

BSC

CDSU

CDSU

SVICM

PCF

RFS

BDS

CDSU

BTS

RFS

BDS

CDSU

BTSMS Um interface

Abis in terface

A interface

A10/A11 in terface

Fig. 1 the Position of ZXC10-BTS in BSS

1.2 Basic Functions Functions of the BTS rack: • Conforming to EIA/TIA IS-2000, EIA/TIA IS-95A and TSB74 air interface

specifications;

• CDMA 450MHz, 800MHz ,1900MHz and 2100MHz frequency configurations;

• Cell breathing function of the CDMA cellular system;

• Blossoming and wilting functions of the CDMA cells;



• Transmit Power Trace Loop (TPTL) control of the CDMA cellular system;

• General call services and call functions such as Markov and TDSO;

• Terrestrial circuit management and radio resource management functions;

• Handover control, including intra-BTS soft handoff, inter-BTS soft handoff and semi-soft handoff within one BSC, and inter-BSC soft and hard handoff;

• Operation and Maintenance (O&M) functions, including performance management, alarm management, configuration management, diagnosis test and security management.

1.3 System Features • Each rack can be configured with two carriers and three sectors or simply six carriers,

and every two racks can be expanded to accommodate four carriers and three sectors.

• Flexible configuration: Any combination of 1/2/3/4 carriers and omni/2 sectors/3 sectors.

• The channel elements of the same carrier can be shared among all sectors, that is, all the channel elements of one carrier form a shared pool.

• The relative independence of the module functions allows flexible configuration for capacity expansion.

• Inter-BTS daisy chain connection is supported, with each E1 providing 192 channels and supporting up to 4 base stations (one-carrier omnidirectional BTS).

1.4 Standards Complied The product conforms to the following standards: • Physical Layer Standard for cdma2000 Spread Spectrum Systems Release 0

• Medium Access Control (MAC) Standard for cdma2000 Spread Spectrum Systems Release 0

• Signaling Link Access Control (LAC) Specification for cdma2000 Spread Spectrum Systems Release 0

• Upper Layer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems Release 0

• Air interfaces comply with EIA/TIA IS-2000 Release A, EIA/TIA IS97-C and TSB74 Specifications

• QB/CU 001-99, Technical Mechanism of 800MHz CDMA Digital Cellular Mobile Communications Network (On probation), China Unicom, 1999

• QB/CU 003-99, General Technical Specifications for 800MHz CDMA Digital Cellular Mobile Communications System Equipment – BSS Part (On probation), China Unicom, 1999



• QB/CU 006-99, Technical Requirements on Interface between 800MHz CDMA Digital Cellular Mobile Communications Network MSC and BSS (On probation), China Unicom, 1999

• QB/CU 007-99, Technical Requirements on Air Interfaces of 800MHz CDMA Digital Cellular Mobile Communications Network (On probation), 1999


2 TECHNICAL INDICES

2.1 System Operating Environment Indices

2.1.1 Physical Indices

2.1.1.1 Dimensions

The dimensions of the ZXC10-BTS rack comply with the 44.45mm (1U) series international standard.

Rack dimensions:

W×D×H = 700mm×600mm×1800mm.

Mounting base dimensions: W×D×H = 700mm×600mm×100mm.

2.1.2 Profile

The outlook appearance of the ZXC10-BTS is shown in Fig.2.



Fig. 2 Profile of the ZXC10-BTS



2.1.3 Equipment Weight and Floor Load-bearing Requirement

Table 1 Weight of the ZXC10-BTS

Configuration Weight 1-carrier three-sector 250kg

2-carrier three-sector 300kg

Empty rack 170kg

The equipment room floor is required to have the load-bearing capacity of 450kg/m2.

2.1.4 Power Supply

2.1.5 Working Voltage

The DC power supply indices of the ZXC10-BTS equipment are shown in Table 2.

Table 2 DC Power Supply Indices of the ZXC10-BTS

Item DC Voltage Nominal value -48V

Allowed fluctuation -40~-57V

2.1.6 Power Consumption

The power consumption of the ZXC10-BTS refers to the total power consumption of the equipment when it works at the -48V DC voltage with each Power Amplifier (PA) outputting 20W of power, as shown in Table 3.

Table 3 Power Consumption of the ZXC10-BTS

Configuration Working Voltage Power Consumption Remarks Single-carrier single-

sector -48V 850W

Single-carrier two-sector -48V 1150W

Single-carrier three-

sector -48V 1400W

Two-carrier single-sector -48V 1100W

Two-carrier two-sector -48V 1650W

Two-carrier three-sector -48V 2200W

Three-carrier three-sector -48V 3600W Total power consumption of

two racks

Four-carrier three-sector -48V 4400W Total power consumption of

two racks

2.1.7 Grounding

The grounding requirement of the ZXC10-BTS is follows:



Joint grounding resistance ≤ 5Ω.

2.1.8 Temperature and Humidity

1. Working temperature: -5°C~ +55°C.

2. Relative humidity: 15% ~ 93%.

2.1.9 Cleanness

The cleanness requirements are as follows: • The density of the dust particles of a diameter more than 5µm shall be less than or equal

to 3×105granules/m3.

• The dust particles shall be non-conductive, non-magnetic and non-corrosive.

2.2 Performance Indices 2.2.1 Reliability

The reliability indices of the ZXC10-BTS are as follows: • Full configuration: Mean Time Between Failures (MTBF) ≥ 35000 hours and MTBCF ≥

100000 hours.

• Mean Time To Recovery (MTTR): 0.25 hours.

• Availability A (%): 99.9308%.

• Average interruption duration per year: 0.05 hours.

Note: MTBCF is short for Mean Time Between Critical Failures. Critical failures are failures that can result in the deterioration of the system performance and the loss of system functions.

2.2.2 RF Indices

2.2.2.1 Band Class 0 (800M) and Band Class 5 (450M)

Table 4 Performance of 800M/450M TX

Working band Band Class 0 (869MHz ~ 894MHz)

Band Class 5 (460~467.5MHz)

Tolerance of the transmitter’s frequency ≤ 5×10-8

Channel bandwidth 1.23MHz

Modulation mode QPSK

Suppression of the spurious conduction

and spurious radiation

In Band Class 0

< -45dBc @±750kHz offset Center Freq (RBW 30kHz)

< -60dBc @±1.98MHz offset Center Freq(RBW 30kHz)

< -60dBc @ other out-band( RBW 30kHz) or ≤-13dBm, whichever is



less. This applies to the situation where the multiple-carrier offset is to

the center of the border carriers.

Suppression of the cellular outband See the table 8

Code domain power The code domain power of the non-active channel should be less than

the total output power and should be 32dB

Total power

The total launch power should be within +2dB and -4dB of the

manufacturer’s rated power (See IS-97D for the definition of the total

power and the testing).

Waveform quality Cross-correlation efficient ρ>0.98

Pilot time tolerance

Less than 3us and should not be greater than 10us. The pilot time

tolerance of all the CDMA channels in the same BTS should be within

±1us. In case the external system clock is interrupted, the timing error

between the BTS and the CDMA system should not be over ±10us.

Time tolerance between the pilot

channel and the code division channel

< ±50ns in the same CDMA channel

Phase tolerance of the pilot channel and

the code division channel

<0.05 radian in the same CDMA channel

Pilot power The pilot power to total power ratio should be ±0.5dB of the

configuration value

Power amplifier (PA) output power 30W

Range of the dynamic linear output > 30 dB

Standing wave ratio of the RFE < 1.50

Table 5 Performance of 800M/450M RX

Working band Band Class 0 (824MHz ~ 849MHz)

Band Class 5 (450~457.5MHz)


Receiving sensitivity Less than -125dBm

Range of dynamic reception

±The lower limit is the receiver sensitivity (less than -125dBm) and

the upper limit is the noise level of the antenna interface (not less than

-65dBm/1.23MHz. When Eb/N0 is 10dB±1dB, FER is less than 1%)

Anti-block performance

At an offset of ±750kHz to the central frequency and single-tone

interference of 50dB (compared to the CDMA signal level without

interference), FER is less than 1.5% and the MS output power

increases not more than 3dB.

At an offset of ±900kHz to the central frequency and a single-tone


interference), FER is less than 1.5% and the MS output power

increases not more than 3dB

Intermodulation spurious response At an offset of +900kHz, +1.7MHz, or -900kHz, -1.7MHz to the



attenuation central frequency and a dual-tone interference of 72dB (compared to

the CDMA signal level without interference), FER is less than 1.5%

and the MS output power increases not more than 3dB

Spurious conduction and radiation

requirements

Less than -80 dBm at the receiving band of the BTS, less than <-60

dBm at the transmitting band of the BTS, and less than <-47 dBm at

other bands, RBW is 30kHz


2.2.2.2 Band Class 1 (1.9G) and Band Class 6 (2.1G)

Table 6 Performance of 1.9G/2.1G TX

Working band Band Class 1 and Band Class 6

Tolerance of the transmitter’s frequency ≤ 5×10-8


Modulation mode QPSK

Suppression of the spurious conduction

and spurious radiation

In Band Class 6

< -45dBc @±885kHz offset Center Freq (RBW 30kHz)

< -55dBc @±1.98MHz offset Center Freq(RBW 30kHz)

< -13dBm @±2.75MHz offset Center Freq(RBW 1MHz)

< -60dBc @ other out-band ( RBW 30kHz) or ≤-13dBm, whichever is

less. This applies when the continuous multiple-carrier offset is to the

center of the border carriers.

Suppression of the cellular outband See the table 8

Code domain power The code domain power of the non-active channel should be less than

the total power and should be 32dB

Total power

The total launch power should be within +2dB and -4dB of the

manufacturer’s rated power (See IS-97D for the definition of the total

power and the testing).

Waveform quality Cross correlation efficient ρ>0.98

Pilot time tolerance

Less than 3us and should not be greater than 10us. The pilot time

tolerance of all the CDMA channels in the same BTS should be within

±1us. In case the external system clock is interrupted, the timing error

between the BTS and the CDMA system should not be over ±10us.

Time tolerance between the pilot

channel and the code division channel < ±50ns in the same CDMA channel

Phase tolerance between the pilot

channel and the code division channel <0.05 radian in the same CDMA channel

Pilot power The pilot power to total power ratio should be within ±0.5dB of the

configuration value

Power amplifier (PA) output power 20W

Range of the dynamic linear output > 30 dB




Table 7 Performance of 1.9G/2.1G RX

Working band Band Class 1 and Band Class 6


Receiving sensitivity Less than -127dBm

Range of the dynamic reception

±The lower limit is the receiver sensitivity (less than -125dBm) and the

upper limit is the noise level of the antenna interface (not less than -

65dBm/1.23MHz. When Eb/N0 is 10dB±1dB, FER is less than 1%

Anti-block performance

At an offset of ±1.25kHz to the central frequency and single-tone


interference), FER is less than 1.5% and the MS output power increases

not more than 3dB.

Intermodulation spurious response

attenuation

At an offset of 1.25MHz, 2.05MHz, or –1.25kHz, -2.05MHz to the

central frequency and a dual-tone interference of 70dB (compared to

the CDMA signal level without interference), FER is less than 1.5% and

the MS output power increases not more than 3dB

Spurious conduction and radiation

requirements

<-80 dBm within the receiving band of the BTS, <-60 dBm within the

transmitting band of the BTS, and <-47 dBm for other bands, RBW is

30kHz


Table 8 Outband Suppression Frequency Range Test Bandwidth Threshold Detecting Method

9kHz~150 kHz 1 kHz -36dBm Peak value

150 kHz~30MHz 10 kHz -36dBm Peak value

30MHz~1GHz 100 kHz -36dBm Peak value

1GHz~12.75GHz 1MHz -30dBm Peak value

806MHz~821MHz 100 kHz -67dBm Valid value

885MHz~915MHz 100 kHz -67dBm Valid value

930MHz~960MHz 100 kHz -47dBm Peak value

1.7GHz~1.92GHz 100 kHz -47dBm Peak value

3.4GHz~3.53GHz 100 kHz -47dBm Peak value

Transmitting frequency band +

1MHz 100 kHz -22dBm Valid value



2.2.3 Clock

2.2.4 BTS Clock

The technical indices for the BTS clock are as follows: • The frequency reference is 10MHz. The precision should be higher than 10-11 in the GPS

locked mode or 10-10 in the holdover mode.

• The temperature variation is required to be less than ±0.5×10-9.

2.2.5 Clock Synchronization Source

GPS adopts the dual thermostat crystal to guarantee that the clock can remain stable within a short term in case the synchronization source is lost temporarily or the BS clock is out of synchronization. Here a HOLDOVER algorithm is adopted, which can guarantee that within 72 hours after the loss of GPS synchronization signals, the phase shift will be less than 10µs, so that the BS can still keep working normally.

2.2.6 Clock System Performance

Frequency difference < 0.05ppm.

Phase difference < 10µs.

2.2.7 Noise

Environmental noise: ≤ 55dBA.


3 BTS HARDWARE

3.1 Overview ZXC10-BTS is the radio part of the BSS. On one hand, it implements the radio transmission and radio channel control for its subscribers (MSs) through the IS2000 air interface. On the other hand, it provides the wired interface functions to BSC. BTS is the radio transceiver controlled by the BSC to serve a certain cell. It can be regarded as a modem with rather complicated functions and structure. Each cell covered by a BTS can be an omnidirectional site or a 2-sector/3-sector one. The ZXC10-BTS comprises a TFS (Timing & Frequency Subsystem), a EBDS_HS/EBDS_IP (Enhanced Baseband Digital Subsystem) and an RFS (Radio Frequency Subsystem), as shown in Fig.3.

Fig. 3 Logical Structure of the BTS

As shown in the above figure, the BTS comprises the RFS, EBDS_HS, EBDS_IP, PS, and TFS.

Its working principles are shown in Fig.4.

BTS

Subsystem

Module

RFS TFS

GPSTM

TCM

PPM

PSMC

PSMD

PSMB

FDM

PS

HPA

TRX

RFE

CCM

RIM

SNM

EBDS_IP

DSM

CHM

CCM

RFIM

SAM

EBDS_HS

CHM

CDSU



Fig. 4 Working Principles of the BTS

3.2 EBDS_HS Subsystem

3.2.1 Overview

The EBDS_HS (Baseband Digital Subsystem) best represents the CDMA features, involving many of the kernel CDMA techniques such as the diversity technique, RAKE, softer handoff and power control. As the control center and communication platform of BTS, it implements the Abis interface communications and the CDMA modem functions.

CCM SmallHIRS

CCMCDSU SAM

CCMCCMCHM

RFIM TFS

IP

CCM1 DSM0

RIM2

CCMCHM1

SIM0

SNM0

RFE

(ALPHA)

TRX

RFCM

HPA HPA

TRX

RFCM

RFE

(BETA)

RFCM RFCM

RFE

(GAMMA)

RFCM RFCM

T

X

T

X

RFE

(ALPHA)

RFE

(BETA)

RFE

(GAMMA)

R

X

1

R

X

0

R

X

1

R

X

0

TRX

HPA HPA

TRX

T

X

T

X

R

X

1

R

X

0

R

X

1

R

X

0

TRX

HPA HPA

TRX

T

X

T

X

R

X

1

R

X

0

R

X

1

R

X

0

RS422RS422

RS232 RS232

SerialDISCO

SerialDISCO

HDLC

HW

PECL

PECL

MLVDS

4XE1 8XE1 －STM 1

HIRS_ABIS IP_ABIS

HIRS _Baseband_RF Interface

RS485

HIRS _Baseband_RF Interface



3.2.2 Working Principles

Logically, the HIRS_BDS consists of four modules: CCM, CHM, RFIM and SAM. Physically, it comprises four boards: CCM, CHM, RFIM and BTS-CDSU (the CDSU module is incorporated here just for the convenience of description). The following figure shows its overall architecture.

Fig. 5 HIRS_ BDS Architecture

The EBDS_HS provides the following functions: • Forward modulation, summation and equalized filtering of the CDMA digital baseband.

• Reverse demodulation of the CDMA digital baseband.

• Providing data and signaling interfaces to RFS.

• Providing the Abis interface to BSC.

3.2.3 Features

The EBDS_HS can be flexibly configured by using different kinds of Channel Processing Modules (CHMs) to support up to two carriers and three sectors. And two EBDS_HSs support the BTS configuration of four carriers and three sectors. One EBDS_HS provides four non-channelized E1 interfaces (Abis interfaces) at the speed of 2Mb/s for load sharing and six interfaces to TRX at most.

3.2.4 Hardware Composition

The EBDS_HS hardware physically resides in one shelf, including 4 Channel Processing Modules (CHMs), 2 Communication Control Modules (CCMs), 2 Radio Frequency Interface Modules (RFIMs), 1 Site Alarm Module (SAM) and 1 Channel/Data Service Unit (BTS-CDSU).

The EBDS_HS shelf has totally 12 slots, sequentially numbered 1~12 from left to right: Slots 3~4 are occupied by the 2 CHMs for the first carrier, slots 9~10 by the 2 CHMs for the second carrier, slots 4 and 11 by the two RFIMs, slot 5 by SAM, slot 8 by CDSU, slots 6 and 7 by the two CCM boards in 1+1 hot backup mode, while slots 1 and 12 by the power boards.

The layout of the slots in the EBDS_HS shelf is shown as in Fig.6.

RS422E1 RS485

Dual Buses

CDSUActive(Standby)

CCMSAM

CHM1 CHM2 RFIM CHM3 CHM4 RFIM

For the first carrier For the second carrier



Fig. 6 Slot Layout of the EBDS_HS Shelf

Input/output interfaces: • Two or four E1 interfaces to BSC

• Interfaces to connect at most six TRXs via cables

• Two RS232 interfaces to read TOD messages for the initialization, management and maintenance of the GPSTM.

• One RS485 interface to communicate with the SAM

3.2.5 CCM

CCM is the communication control module in the EBDS_HS shelf of ZXC10-BTS, controlling the data/signaling routing, signaling processing, resource management and maintenance of the whole EBDS_HS in the centralized mode.

The CCM provides the following functions: • Signaling processing and forwarding.

• Maintaining, managing and reporting radio channel resources.

• Managing and maintaining the modules of the EBDS_HS.

• Reading TOD messages, and maintaining & managing the GPSTM.

• Software download and data distribution.

3.2.6 CDSU

3.2.6.1 Overview

In the CDMA system, the interface between BSC and BTS is called the Abis interface, which connects BSC and BTS via an E1 trunk. The CDSU board is the module that implements the Abis interface functions. It has two types of panels. One is relatively narrow, used on the BTS side. The other one is relatively broad, used on the BSC side. Classified by the capacity, there are the 2-E1 CDSU boards and the 4-E1 CDSU boards.

PSMB

CCM

11

CCM

10

SAM

9876

RFIM

54

CHM

3

CHM

2

CDSU

121

CHM

CHM

RFIM

PSMB



3.2.6.2 Basic Functions

CDSU provides the Abis interface functions, implementing the conversion between the BSS internal serial buses and the E1 serial links. Its performance indices are as follows:

1. 2-E1 CDSU board • 32-frame buffer per E1 channel

• 4-level flow control per E1 buffer

• Star networking

• Load sharing and backup of the two E1s

2. 4-E1 CDSU board • Data of each E1 interface are given different priorities. For data of a higher priority, 500

frames of buffer space are provided. For data of a lower priority, 1000 frames of buffer space are provided.

• Broadcast data support

• Star networking

• Daisy chain networking

• Load sharing and backup between E1 links

• Delay test on the Abis interface and the large HIRS

• Fully compliant with the 2-E1 CDSU board

3.2.7 SAM

The SAM (Site Alarm Module) resides in the EBDS_HS shelf on the BTS side. Its major function is to monitor the running status of the power modules and fans, detect such environmental signals as entrance control, flood, temperature, humidity and smoke, and report these results via CCM to the O&M console at the background for processing. In addition, it provides RS232 and RS485 interfaces for the connections with external monitoring devices.

The SAM board has the following major functions: • Actively reports alarm signals to and receives/executes the control commands from the

CCM board.

• Collects the power and fan alarm signals from the power boards via a half-duplex RS485 bus.

• Communicates with external environment monitoring devices via two RS232 interfaces and one full-duplex RS485 interface.

• Monitors and gives alarms for entrance control, smoke and flood.

• Monitors the humidity inside the rack, the equipment room temperature & humidity, and the temperature at the upper, middle and lower parts of the rack.



• Provides four standby input ports and two standby output ports.

3.2.8 RFIM

RFIM is an EBDS_HS component in BTS to connect the digital subsystem and the RFS. It communicates with CCM via the transceiver bus and is controlled by CCM.

RFIM has the following basic functions: • Forward/reverse transmission and processing of baseband data;

• Transmission and processing of control signals (like configuration control and status alarm);

• Distributing 16CHIP and PP2S clock signals to the CHMs.

3.2.9 CHM

CHM resides in the EBDS_HS shelf. Its major function is to modulate and demodulate the CDMA channels. It connects to CCM via the transceiver bus and to RFIM via the baseband data bus.

CHM has the following basic functions: • Provides transceiver interfaces to CCM;

• The forward link modulates the voice and data frames sent by CCM via the transceiver interface and sends them to RFIM;

• The reverse link receives the antenna signals distributed by RFIM via the baseband data interface, demodulates them into voice and data frames and then sends them to CCM via the transceiver interface;

• Supports the physical layer of CDMA-2000: IS-2000-2 RELASE 0.

3.3 EBDS_IP Subsystem

3.3.1 Overview

As a control center and communication platform of the BTS, EBDS_IP susbsystem implements communication with Abis interface and CDMA baseband modulation/demodulation to achieve EV-DO even EV-DV functions.

3.3.2 Basic Functions

Described below are basic functions of the EBDS_IP: • Forward modulation, summation and equalized filtering of the CDMA digital baseband;

• Reverse demodulation of the CDMA digital baseband;

• Providing data and signaling interfaces to RFS;



• Providing the Abis interface to IP BSC.

3.3.3 Features • Supporting 2-carrier 3-sector at most.

• One EBDS_IP provides 8 non-channelized E1 interfaces (Abis interfaces) at a rate of 2Mb/s for load sharing.

• One EBDS_IP provides a maximum of 6 interfaces to be connected to TRX.

• Built-in SDH (STM-1) transmission.

• Supporting daisy chain connection with the EBDS_HS.


Physically the EBDS_IP is composed of one EBDS_IP shelf, two CHMs, two CCMs, one RIM, one SIM, one DSM and one SDH transmission board SNM, as shown in Fig.7.

Fig. 7 EBDS_IP Position Schematic Diagram

3.3.5 CCM As the core of signaling processing, resource management and O&M of the whole BTS, Communication Control Module (CCM) is located in the main BDS shelf and responsible for routing of data and signaling in the BTS. Also, it is the center for the acknowledgement of signaling transfer. Signaling are transferred via the CCM between modules of BTS, and between modules of BTS and modules of BSC (such as SDM, VBM, CPM, etc). It provides two basic functions: constructing BTS communication platform, and BTS centralized control center.

CCM_1 is made up of CCM2 motherboard, MPB (Middle Level Processor Board), and ESB2 (Ethernet Switch Board-Type2).

3.3.6 CHM_0

CHM_0 is responsible for modulation and demodulation of the physical layer of CDMA2000 1X, based on ASIC chip CSM5000 made by QUALCOMM. It provides a maximum configuration of forward 512 CEs and reverse 256 CEs, i.e., supports baseband processing of nearly 6 sectors of CDMA2000 1X.

CHM

RIM

CHM

CHM

CCM

CCM

EBDS_HS

EBDS_HS EBDS_IP

DSM

SNM

SAM

SIM

RFI

M

CHM

CCM

CCM

CDSU

CHM

RFIM

CHM

PSMB

PSMB

EBDS_IP



CHM_0 is made up of one CHM0 motherboard, one MPB(Middle Level Processor Board) of CPU and seven CEB0s (Channel Element Boards) of CSM5000. There is one CSM5000 on the CHM0 motherboard.

3.3.7 CHM_1

CHM_1 is responsible for modulation and demodulation of the physical layer of CDMA2000 1X EV-DO, based on ASIC chip CSM5500 made by UALCOMM. It provides a maximum configuration of forward 192 CEs and reverse 96 CEs, i.e., supports baseband processing of 3 sectors of CDMA2000 1X EV-DO.

CHM_1 is made up of one CHM1 motherboard, and CEB1 (Channel Element Board) of CSM5500. There are four CSM5500 on the CHM1 motherboard.

3.3.8 DSM

3.3.8.1 Overview

DSM (Data Service Module) located in the EBDS_IP shelf is responsible for communication at ABIS interface between BTS and BSC. Based on the all-IP structure recommended by 3GPP2, DSM will implement two-way communication of protocols such as IP/CUDP/PPPmux/MP/HDLC, and provide HDLC/E1 interface. When configured with built-in SDH, it can provide HW interfaces.

3.3.8.2 Composition

There are various types of DSM boards, as shown in Table 9.

Table 9 Types of DSM

No. Name Composition 1 DSM_0 DSM_0=DSM0+LPB0+2 CIB0+OWB0

2 DSM_1 DSM_1=DSM0+LPB0+CIB1+CIB0+OWB0

3 DSM_2 DSM_2=DSM0+LPB0+CIB0+CIB1+OWB0

4 DSM_3 DSM_3=DSM0+LPB0+2 CIB1+OWB0 5 DSM0 Data Service Module Motherboard (8E1)

Note: LPB0: Low Level Processor Board Type 0

CIB0: 4E1/T1 (E1/T1 Circuit Interface Board)

CIB1: 8E1/T1 (E1/T1 Circuit Interface Board)

OWB: Order Wire Board

3.3.9 Basic Functions • Supporting broadband processing of two-way 8XE1 links to meet the requirement of link

bandwidth at ABIS interface for a maximum configuration of 2-carrier 3-sector of DO service in “IP + HIRS” system;



• Providing orderwire phone and switching function;

• Supporting daisy chain cascade;

• Supporting built-in SDH.

3.3.10 SNM

SNM (SDH Network Module) located in the EBDS_IP shelf is responsible for SDH transmission at ABIS interface between BTS and BSC. It connects with DSM through the HW, and can provide 48*E1=6*16M HW at most at BTS side. For EBDS_IP solution, only one 16M HW can meet the maximum configuration requirement of the system.

Belows are basic Functions of SNM module • A maximum configuration of four pairs of optical interfaces can support various

complicated networkings such as four-fibre ring networking, dual-ring networking, tree networking, etc., two pairs of which are mandatary configuration supporting basic two-fibre ring networking, and the other two pairs can be added in subcard mode.

• SNM interacts with CCM at BTS side via FE line;

• SNM clock processing involves extracting the clock source from the line for DSM that sends it to GCM. Meanwhile GCM provides highly reliable circuit clock as a unified clock reference for BTS and distributes it to all ABIS interfaces of the BDS shelves;

• Built-in SNM exchanges data with ABIS interface (DSM);

• Providing access to orderwire phone at BTS by using the network management path of SDH to facitate maintance personnel at BTS side to communication with BSC or other BTS.

3.3.11 RIM

RIM (Radio Interface Module) located in the EBDS_IP shelf is responsible for providing interface between CDMA baseband processing with RF processing. It performs linear summation of baseband data to achieve “CE sharing”, establishes data transmission interface between baseband and RF, distributes system clock of BDS, and completes communication between baseband CCM and RF CCM.

3.3.12 SIM

SIM_0 (System Interface Module) located in the EBDS_IP shelf is responsible for processing of all system interfaces of the IP-BDS.

Its basic functional interfaces involve: • Uplink 8*E1 match network connected to BSC and the protection circuit;

• Downlink 8*E1 match network cascaded with BTS daisy chain or accessing ABIS transmission via the external extended device and the protection circuit;

• Interconnection interface between the EBDS_IP and the EBDS_HS;



• Interconnection interface between the EBDS_IP and the HIRS_TFS: When an independent EBDS_IP is configured in the main BTS rack, CCM_1 of the EBDS_IP implements communication and control over GPSTM of the HIRS-TFS; As for other configuration, IP-BDS receives TOD messages;

• Interconnection interface between the EBDS_IP and the HIRS_RFS: The EBDS_IP provides the same cable interface as the HIRS_RFS.

3.4 RFS

3.4.1 Overview

BTS is an inseparable part of the CDMA cellular network system to implement the air interface functions. And yet, BTS must depend on its RFS component to exchange radio signals, especially when the CDMA system has adopted such techniques as power control, cell breathing, soft handoff, GPS timing, and numerous diversity reception means. This feature has distinguished the BTS RFS of the CDMA system from the RFSs of other systems. The major role of the RFS is to implement the air interface functions via the antenna and provide the interface to the BDS via the interface module. In addition, it modulates/demodulates CDMA signals in sending/receiving, implements the relevant detection, monitoring, configuration and control functions, and provides such flower functions as cell breathing, blossoming and wilting.


Based on the BTS structure in the CDMA system, RFS can be divided into two subsystems: The external antenna feeder subsystem and the internal transceiver subsystem. Of them, the antenna feeder subsystem is again composed of the antenna, the feeder and other structural installation parts. The specific model and composition of this subsystem greatly depend on the actual network plan. Typically, an antenna feeder subsystem consists of antenna, antenna jumpers, main feeders, a lightning arrester, cabinet-top jumpers and the grounding parts. The transceiver system is composed of an RF TRX, a High Power Amplifier (HPA), and an Radio Front End (RFE). The specific RFS configuration is subject to the overall BTS configuration. A single BTS rack can be flexibly configured to provide as few as only one sector with a single carrier or as many as three sectors with two carriers. In the case of combined cabinets, up to three sectors with four carriers can be configured. The RFS configuration is also very flexible, adjusting to the different BTS configuration schemes of different users. The following text will explain the system architecture of RFS by use of three configuration examples: 1-carrier 3-sector configuration; 2-carrier 3-sector configuration, and 4-carrier 1-sector configuration.

The 1-carrier 3-sector configuration of RFS is shown in Fig.8. Each sector has one TRX, one RFCM (resides in the same shielding box as TRX, forming the TRX board), one HPA, one RFE-DUP that specially adapts to this type of configuration, one RFE-DIV and two antennae (one transceiver antenna and the other diversity receiving antenna).



RFE-DUP

TRX

RFCM

EBDS shelf

TRX

RFCM

TRX

RFCM

RFE-DUP

RFE-DUP

RX0

RX1

RX0

RX1

RX0

RX1

RFE-DIV

RFE-DIV

RFE-DIV

HPA

TX

HPA

TX

HPA

TX

Fig. 8 Working Principles of the 1-Carrier 3-Sector RFS

The 2-carrier 3-sector configuration of RFS is shown in Fig.9. Each sector has two TRXs, two RFCMs, two HPAs, two RFE-DUPs that specially adapt to this type of configuration and two antennae. One of the antennae functions as the transceiver of the first carrier and the diversity receiver of the second carrier at the same time, while the other antenna functions as the transceiver of the second carrier and the diversity receiver of the first carrier.



RFE-DUP

TRX

RFCM

EBDS shelf

TRX

RFCM

RFE-DUP

RFCM RFCM

RFE-DUP

RFCM RFCM

TX

TX

RFE-DUP RFE-DUP RFE-DUP

TRX TRX

TX

TX

TRX TRX

TX

TX

RX1

RX0

RX1

RX0

RX1

RX0

RX1

RX0

RX1

RX0

RX1

RX0

HPA HPA HPA HPA HPA HPA


The 4-carrier 1-sector configuration of RFS is shown in the Fig. 10. Each sector has four TRXs, four RFCMs, four HPAs, two antennae, two RFE-COM-DUPs and two RFE-COM PA cavity combiners that specially adapt to this type of configuration. One of the antennae functions as the transceiver of the first carrier and the diversity receiver of the second carrier at the same time, while the other antenna functions as the transceiver of the second carrier and the diversity receiver of the first carrier.



RFE-DUP

TRX

RFCM

EBDS shelf 0

HPAHPA

TRX

RFCM

RFE-DUP

RFCMRFCM

TX

RFE-COM RFE-COM

TRX

HPA HPA

TRX

RX1

ALPH0 ALPH1

RX1

RX0 T

X

RX0

TX

RX1

RX0

RX1

RX0T

X

EBDS shelf 1


3.4.3 Features

RFS has the following features: • Providing the air interface for the ZXC10-BSS system.

• Flexible configuration: The RFS configuration directly decides how many carriers and sectors the ZXC10-BSS system can provide.

• Determining the main forward/reverse RF indices of the ZXC10-BSS system.

• Modular design to guarantee that the heat under high forward output power and high power consumption be dissipated evenly for enhanced reliability.

• Decentralized cavity design and highly selective receiver, ensuring secure separation, high sensitivity and high selectivity.



• Fine EMC&EMI design, conforming to all the relevant national and international standards.


The RFS hardware resides in three shelves, TRX, HPA and RFE, as shown in the following figures. In the 2-carrier 3-sector configuration, there is only one rack, but in the configurations with more carriers, there are two racks.

TRXTRXTCM

GPSTMFDM

FDM

TRX TRX TRX TRXGPSTM

4 98651 2 3 107

Fig. 11 TRX Shelf

HPA HPAHPA HPAHPAHPA HPA BTM HPAHPA HPAHPAHPA

75 631 2 4

Fig. 12 HPA Shelf

RFE RFE RFE RFE RFERFE

1 2 3 4 5 6

Fig. 13 RFE Shelf

RFS provides the following input/output interfaces: • Antenna interfaces of the antenna feeder subsystem

• Data interfaces of the EBDS_HS

• Alarm and configuration & maintenance interfaces of the EBDS_HS



3.4.5 TRX

TRX ties RF signals with baseband signals. Each TRX corresponds to one sector and one carrier. On one hand, it receives the main and diversity receiving signals of the two RFEs of this sector, conducts down conversion, median frequency filtering, AGC processing and I/Q demodulation on these signals to convert the received modulated RF signals into baseband I/Q signals. On the other hand, it receives the forward baseband I/Q signals, and conducts I/Q modulation, median frequency filtering and up conversion on these signals to convert them into modulated RF signals. In addition, it executes the TPTL power control operations. Therefore, TRX is critical to RFS for the processing of Tx/Rx signals.

TRX comprises two receiving units, one transmitting unit, one Frequency Synthesizer unit (FS), one TPM and one RF Control Module (RFCM), as shown in Fig.14.

RFCM

IQ0

IQ1

RX0

RX1

FS

TX

RX0-I

RX0-Q

RX1-I

RX1-Q

12MHz

TX-I

TX-Q

Fig. 14 Working Principles of the TRX

3.4.6 HPA

HPA is used to amplify the power of the forward Tx signals from TRX, send them to RFE for filtering and then to the antenna for transmission. Its working current is strong and its temperature is high in working. In addition, the CDMA signals are non-constant envelope ones. To prevent the regeneration of frequency spectrum from occurring to the signals, the requirement on the linearity of HPA is very high.

HPA provides the following functions: • Amplifies the forward Tx signals output by TRX.

• Responds to the “enable/disable” control signals from the system.

• Detects the internal RF signals, temperature, and others.

• Monitors the running status and reports an alarm when necessary according to the detection results.



3.4.7 DUP

DUP is an important module in RFE that has the transceiver function. When this module is used, only one antenna is needed for the transmitting/receiving of RF signals. It is commonly adopted in Frequency Division Duplex (FDD) systems.

DUP provides the following functions: • Implements the duplex function for transmitting and receiving signals.

• Filters the forward Tx signals.

• Executes the wave-filtering and low-noise amplification of the reverse signals received by the antenna and outputs the signals to separate circuits.

• Detects the power and reports the detected power value.

• Detects the VSWR of the antenna feeder subsystem and reports the VSWR alarm information.

• Monitors the status of the Low Noise Amplifier (LNA) and reports an alarm when necessary.

The working principles of the DUP are shown in Fig.15.

DUPLEXER

PDET

VSWR

LNA

PSI

HPA

ANT

Rx0Rx1Rx2Rx3

Panel

Tx

RxFWD

REV

Backplane

Fig. 15 Working Principles of the DUP

3.4.8 DIV

DIV is an important module in RFE that has the diversity receiving function.

DIV provides the following functions: • Executes the wave-filtering and low-noise amplification of the reverse signals received

by the antenna and outputs the signals to separate circuits.

• Monitors the status of the low-noise amplifier and reports an alarm when necessary.



3.4.9 COM

RFE-COM is a component in the RFE module. It implements the important combiner function in each sector when three or four carriers are configured.

COM provides the following functions: • Combines the signals transmitted by two carriers of different power.

• Detects and reports the power of the signals transmitted by different carriers.

The working principles of the COM are shown in Fig.16.

Fig. 16 Working Principles of the COM

3.4.10 COM-DUP

COM-DUP is an important module used jointly with COM in the RFE module and has the transceiver function.

COM-DUP provides the following functions: • Implements the duplex function for both transmitting and receiving signals.

• Filters the forward Tx signals.

• Executes the wave-filtering and low-noise amplification of the reverse signals received by the antenna and outputs the signals to separate circuits.

• Detects the total output power of the antenna and gives low-power alarms.

• Detects the VSWR of the antenna feeder subsystem and reports the VSWR information.

• Monitors the status of the low-noise amplifier and reports an alarm when necessary.

• Injects and fetches BTM signals.

COM

PDET2

PDET1

PSI

HPA2

COM

BackplanePanel

HPA1



3.5 TFS

3.5.1 Overview

TFS is an important subsystem of the CDMA system and provides the timing and frequency references. The EBDS_HS and RFS subsystems depend on it to provide the baseband and RF clock signals.

TFS generates the synchronous timing reference signal source and the frequency reference signal source in the CDMA system. It receives signals from the GPS satellite system, extracts the 1PPS and pilot signals, generates the PP2S, 19.6608MHz and 12MHz signals and relevant TOD messages by using the 1PPS signals as the phase-locking reference, and distributes the clock signals.

For the network security of the CDMA system, TFS can receive signals both from a GPS satellite and from a GLONASS satellite.


TFS consists of three boards, GPSTM, TCM and FDM, as shown in Fig.17.

TCMGPSTMFDM

16CHIP

PP2S

16CHIP

PP2S

10MHz 10MHz

10MHz

GPS antenna

6 channels of12MHz

GPSTM

GPS antenna

4 channels of 16CHIP

4 channels of PP2S

Fig. 17 Working Principles of the TFS

TFS provides the following functions: • Provides 16CHIP and PP2S baseband clocks for the baseband subsystem.

• Provides 12MHz frequency source for the RFS subsystem.

• Provides timing reference for the CDMA system, that is, TOD messages.



3.5.3 Features

TFS (Timing & Frequency Subsystem) provides the PP2S timing reference, the system clock, the TOD messages and the 12MHz reference clock in the BTS; therefore, it is the timing and frequency reference at the wireless synchronization part of the whole CDMA system and is also the standard time provider of the whole system.

As the clock part of the whole CDMA system, TFS is critical to the reliability and stability of the system, so its major module GPSTM is required to be in hot backup configuration for enhanced system stability.


The TFS in a BTS physically consists of two GPSTM boards, one TCM board and one FDM board, as shown in Fig.31. Each GPSTM outputs two channels of 16CHIP signals, two channels of PP2S signals and two channels of TOD messages, one for the local rack and the other for the extended rack. Each TCM outputs two channels of 10MHz signals, four channels of 16CHIP signals and four channels of PP2S signals, two for the local rack and the other for the extended rack. FDM outputs six channels of 12MHz signals.

One or two GPSTMs can be configured in TFS as required. The TFS hardware occupies slots 4~7 in the TRX shelf in the BTS cabinet (as shown in the Fig.18). Slots 1~3 and 8~10 are for TRX boards.

TRXTRXTCM

GPSTMFDM

FDM

TRX TRX TRX TRXGPSTM

4 98651 2 3 107

Fig. 18 Slot Layout of the TFS in the TRX Shelf

TFS provides the following output interfaces: • Four channels of 16CHIP signals and four channels of PP2S signals carried by shielded

twisted pairs to RFIM, with the signal level being PECL.

• Six channels of 12MHz signals carried by coaxial cables to the TRX module, with the signal level being SINE.

• Two channels of TOD messages carried by shielded twisted pairs from the local rack and the extended rack to CCM.

The signals input to TFS are: • GPS satellite signals, which are received by the GPS antenna and transmitted in the

coaxial shielded twisted pairs.

• IIC bus signals, carried by shielded twisted pairs to CCM.



3.5.5 GPSTM

GPSTM is important for the CDMA system. In the CDMA mobile communication system, both the transmission and radio networks need to be synchronized. For the transmission, the active/standby synchronization mode is generally adopted. For the radio network, the GPS synchronization mode is adopted, which requires all the radio interfaces of the whole cellular system to synchronize to the same standard clock provided by the GPS system. The synchronous timing solution for the CDMA system proposed by ZTE requires that BTS and BSC synchronize to the standard clock signals provided by GPS. GPSTM is the module to provide the standard clock signals and relevant system references to the BTS and BSC. The GPSTM in a BS is to provide the 16CHIP clock signals and PP2S signals to the BDS subsystem, the 10MHz sine reference signals to the RFS subsystem and the TOD messages to the whole system.

GPSTM provides the following functions: • Receives GPS signals and outputs the PP2S, 16CHIP, 10MHz signals and TOD signals

via phase locking.

• Guarantees through the holdover function that the drift is no more than 10µs within 24 hours when it fails to capture any satellite signal. The GPSTM of the ZXC10-BTS can even guarantee the drift is no more than 10µs within 72 hours.

• Allows active/standby switchover

• Detects and reports the running status of the board.

3.5.6 TCM

TCM receives and merges the 10MHz signals from the active and standby GPSTMs and then distributes the merged signals. On the other hand, it also receives the PP2S and 16CHIP frequencies from the active and standby GPSTMs to lock their phases and then generates the new PP2S and 16CHIP frequencies.

TCM functions just like a hinge between the active and standby GPSTMs to guarantee the continuance of PP2S and 16CHIP frequencies when active and standby GPSTMs switch over, thus avoiding call drops at switchover. For enhanced reliability, the module has been designed in such a way as to contain the least unreliable components, thus maintaining the simplicity of circuitry. At the same time, such aspects as heat dissipation and electromagnetic compatibility have been taken into consideration in the design.

TCM provides the following functions: • Receives the clock signals from the active and standby GPSTMs.

• Merges the 10MHz signals and then distributes them.

• Receives the 16CHIP and PP2S signals from the active and standby GPSTMs.

• Locks the phase of the 16CHIP signals.

• Regenerates the PP2S signals.



3.5.7 FDM

FDM is inserted in the TRX shelf of the BTS cabinet. In a 1.9G system, it receives and merges the 10MHz signals from TCM and then distributes the merged signals. In an 800MHz system, it receives and locks the phase of the 10MHz signals from TCM and outputs 12 MHz signals to TRX. As the active/standby switchover can result in the discontinuity of the 10MHZ signals, to avoid call drops, FDM first locks the phase and then buffers the 10MHz signals to output continuous 12MHz signals. For enhanced reliability, the module has been designed in such a way as to contain the least unreliable components, thus maintaining the simplicity of circuitry. At the same time, such aspects as heat dissipation and electromagnetic compatibility have been taken into consideration in the design.

FDM provides the following functions: • Receives the clock signals from TCM.

• Distributes the 10MHz signals or first locks the phase of and then distribute the 10MHz signals.

• Reports the working state of the FDM board via its I2C.

3.6 PS

3.6.1 Overview

PS (Power Subsystem) supplies power to the boards of BTS. It also monitors itself and will inform the background of any fault if detected.

3.6.2 Features • PSMD distributes one line of -48V DC input power to the BTS shelves, and at the same

time monitors and controls the working states of the PS and fans.

• PPM supplies 27V DC power to RFS. It is configured in the N+1 backup mode and is of a temperature-control forced air cooling structure for heat dissipation. Its parallel load sharing function can ensure the requirement of the current equalization even when there are as many as five modules.

• Both PSMC and PSMB are configured in the 1+1 backup mode for enhanced reliability. In normal situation, the two power boards together shoulder the power supply responsibility. If either one becomes faulty, the other one will shoulder the entire power supply responsibility alone.


The power distribution plug-in box supplies the –48V DC power to the ZXC10-BTS rack and monitors its power supply. The working principles are illustrated in Fig.19.



-48V DCpower supply

Protectionunit

Communicationinterface

Fig. 19 Working Principles of the PS


The PS of ZXC10-BTS consists of an input protection unit and a plug-in box shelf. The plug-in box shelf comprises four types of modules: PSMD, PSMC, PPM and PSMB, as illustrated in Fig.36. They shoulder the +27V, ±12V and -48V power distribution functions and there are totally five PPMs, two PSMCs and one PSMD.

The input protection unit comprises a feed-through filter. The power monitoring signals are reported via the RS485 communication interface of PSMD.

PSMD PPM PPM PPM PSMC PSMCPPMPPM

1 3 4 6 7 852

Fig. 20 PS Shelf

3.6.5 PSMD

PSMD is inserted in the power distribution shelf of BTS.

PSMD provides the following functions: • Distributes one channel of -48V DC input power to all shelves.



• Monitors and controls the running status of the PS and fans.

• Provides one RS485 interface to the SAM board for communications.

3.6.6 PPM

PPM is inserted in the PS shelf of the BTS cabinet to supply 27V DC power to RFS. It is configured in the N+1 backup mode and is of a temperature-control forced air cooling structure for heat dissipation. Its parallel load sharing function can ensure the requirement of current equalization even when there are as many as 5 modules. For the power input, its pre-charge soft startup mechanism can guarantee a small dash current. As for the power output, its diodes can prevent back flow. Therefore, the PPM is hot swappable.

3.6.7 PSMC

PSMC is inserted in the PS shelf of the BTS cabinet to supply ±12V power. Its core component is a commercial DC/DC transformer module. Plus the peripheral circuits that implement the protection, filtering and detection functions, it actually serves as a stable and reliable power board to convert the -48V input power to the ±12V output power.

3.6.8 PSMB

PSMB is inserted in the EBDS_HS shelf of the BTS cabinet to supply power to the digital subsystem. To guarantee the reliable performance of the digital subsystem, PSMB is configured in the 1+1 backup mode. In normal situation, the two power boards supply power in parallel to the BDS. If either one becomes faulty, the other one is to supply power to the entire shelf. At the same time, PSMB needs to report its own working state to the system monitoring unit, so it also provides the 485 interface for communications between them.

PSMB provides the following functions: • Converts the -48V DC input power to the +5V DC power for the BDS shelf.

• Adopts the 1+1 backup mode.

• Outputs over-/under-voltage alarm information via the RS485 interface with its built-in CPU.

3.7 LFM in the Transmission Subsystem The Local Fiber Module (LFM) provides a means to extend the transmission distance without hardware changes. Here, LFM is implemented as a simple interface module.

LFM provides the following functions: • Implements the level conversion between the physical fiber interface and the board.

• Provide a means to extend the transmission distance by using fibers.


4 BTS SOFTWARE

4.1 Overview The ZXC10-BTS software resides in three modules: CCM, CHM and TRX. The 800MHz, 450MHz,1900MHz and 2100MHz base stations use the same system software, which does not reside in the remote RF station. The software system is divided into four subsystems: Operating System Subsystem (OSS), Service Processing Subsystem (SPS), Operation & Maintenance Subsystem (OMS) and Data Base Subsystem (DBS), as shown in Fig.21.

SPS

DBS

OMS

OSS

Fig. 21 ZXC10-BSS Software Composition

Inside BSS, the suite of software is composed of the programs that are distributed on the boards and background processors, that is, a distributed processing mode is applied. • SPS: Based on the standards of the Um interface (IS-2000), it implements cdma2000 1X

cellular mobile services.

• OMS: It provides interfaces to the authorized administrators and the upper-level NMS, thus achieving operation and maintenance of the entire BSS.

• EBDS: It manages the BSS data in a centralized way, and is the support system of the upper-layer applications (SPS and OMS).



• OSS: As the natural extension of the hardware and commercial-purpose embedded operating system, it encapsulates details of the bottom-layer hardware and operating system and provides the operation and communication mechanisms necessary for the upper-layer applications (SPS, OMS and DBS).

Due to their different functions, the subsystems have different characteristics and positions.

From the software hierarchy perspective, OSS is the bottom-layer BTS software that serves as the extension of the hardware system and the commercial-purpose realtime multi-task operating system to encapsulate the bottom-layer information and to provide a virtual machine platform for the operation and communication of the upper-layer software. SPS, OMS and EBDS are applications that run on the OSS software.

In the application layer, DBS, as the data collector and manager, passively provides services to the other two applications, SPS and OMS. It is system support software.

The purpose of BSS is to implement the CDMA service functionalities. The OMS application provides the system management functions while the SPS application is an object under the management of OMS. They are two independent networks: One is the service network, the other, the O&M network. They interact with each other via the O&M primitives.

4.2 CCM Software

4.2.1 Overview

CCM is the signaling processing, resource management and O&M center of the entire EBDS subsystem. It is also responsible for data signaling routes of the EBDS. And at the same time, it is the central point for signaling transmission acknowledgement. The signaling transmitted between any module inside the EBDS and that outside the EBDS is always forwarded by CCM.

4.2.2 DBS

The DBS that resides on CCM manages the data at the ZXC10- BTS in the centralized mode. It is a database embedded in real time to satisfy the requirements of the foreground applications for real-time data operations, characteristic of concise structure and small capacity.

The foreground DBS on the CCM provides the following functions: • Data organization and management: DBS organizes and manages some general BTS-

related data, including the hardware configuration data and radio resource management data.

• Data loading and maintenance:DBS is responsible for the creation and maintenance of the memory databases, data loading and storage, synchronization of the active and standby databases, performance statistics, dynamic data observation and others.

• Providing the access interface:The other subsystems need to use the access interface provided by DBS to access the databases.



4.2.3 Functional Distribution

The foreground DBS on the CCM maintains two types of data, the hardware configuration data and the radio configuration data. It comprises four components, as shown in Fig.22.

D_K

D_VD_MD_S

Fig. 22 Structure of the Foreground EBDS

D_S: Service, database maintenance module

D_M: Method, relational database table method module

D_V: View, access interface module

D_K: Kernel, kernel module • D_V: access interface module

To guarantee the data security and consistency, the database users are not allowed to manipulate the databases directly, but through D_V, which receives the data manipulation requests, executes the required operations and then returns the results. • D_M: relational database table method module

D_M can create objects by invoking the primitives provided by the kernel module. It can also load/add data to the objects and delete/modify the data of the objects to maintain the integrity of the database table relations. • D_K: kernel module

D_K provides the primitives for the manipulations of the relations, index and queue objects. These primitives can be used to construct specific methods to manipulate the instances of the objects. • D_S: database maintenance module

D_S can implement tasks such as database initialization, regular database backup, database loading, active/standby database synchronization and dynamic database monitoring.



4.2.4 RCM

The RCM hardware resides on the CCM board, as illustrated in Fig.23. RCM connects with the RFCM of the RFS through RFIM, which only implements the forwarding function. Therefore, RCM is regarded as being directly connected with RFCM logically.

RFS

BSC

CCMAbisc

AmRCM

CEC

RFIMRFCM BSSAP

DSCHP

Abisd

CHM

Fig. 23 Connections Between RCM and Other ModulesThe S_RCM software is a module of the SPS. It configures and manages the CHMs and CEs, and is responsible for the RFS parameter configuration and status control.

S_RCM provides the following functions:

1. CE-related functions • CHM initialization at power-on.

• CE enable/disable control, configuration, parameter modification.

• Overhead message construction.

• CHM/CE reconfiguration.

• Establishment, parameter configuration and release of the traffic channels.

• Radio resource allocation.

• Flexible F-SCH scheduling.

• Control channel handshaking.

2. RFCM-related functions

RFCM configuration and management: • RFCM parameter configuration and modification.

• HPA control.



• RFCM state/alarm query.

• RFCM alarm.

• Sending/receiving link attenuation control.

• Auto calibration.

Cell-related control: • TPTL enable/disable.

• Cell blooming and wilting control.

• Cell breathing control.

3. Other functions: • FDM and TCM configurations.

• Active/standby switchover.

• BTS overload control.

4.3 TRX Software The TRX software runs on the single-chip microcomputer of the RFCM board, able to be downloaded from the background. It is the monitoring center of RFS and implements the communications between EBDS and RFS. Its major functions are as follows:

1. Signaling reception, processing, generation and transmission

The RFCM chip reads the CCM signaling data through the FPGA interrupt, analyzes the signaling contents, sets appropriate flag bits or assigns specific parameter values for them to be processed by the main program.

It can generate signaling messages based on the detected status information of the functional modules and send them to the CCM. These signaling data are sent to and processed by FPGA.

2. Controlling and monitoring the functional units in RFS via the IIC bus

The RFCM chip, as the main node of the I2C bus, controls the bus operations. It controls and monitors the relevant functional units by reading from or writing to the interface devices on the bus, such as I2C I/O expansion, EEPROM and I2C ADC/DAC. The details are as follows: • TRX configuration, status detection and functional control

• HPA enable/disable control

• HPA status check

• RFE status check

VSWR alarm, LNA fault detection and forward transmitting power monitoring in the mode of interrupt or regular query.



3. RFCM monitors the entire RFS and reports the alarms produced by its modules, including: • HPA over-power alarm

• HPA over-temperature alarm

• HPA component failure alarm

• HPA VSWR alarm

• RFE VSWR alarm

• LNA over-/under-current alarm of RFE Rx signals

• I2C component alarm

4. Status information report

The RFCM software may report the following status parameters to the RCM software: • RFE transmitting power

• RSSI values of the main and diversity receiving links

• Forward TX attenuation values

• Reverse RX attenuation values (main & diversity)

• The instantaneous error, average and integral values of I2+Q2

5. Remote software download

The TRX software can be downloaded from the background remotely, thus providing a high-speed reliable means for future board software upgrading.

4.4 CHM Software The CES (Channel Element Subsystem) is based on the CEM code developed by Qualcomm. It drives the CSM chip and implements the coding/decoding and modulation/demodulation of the physical layer of the air interface. The CES software resides on the CHM board. As illustrated in Fig.24, the CES comprises the CEM and CEC modules.



Fig. 24 Software Modules of the CESDrive: The drive layer software module of CEM; its source code is developed by Qualcomm.

• Application: The application layer software module.

• Riop: Running information observation module.

• PAM: Performance measurement module.

• Dmp: diagnosis & test proxy module.

Both Drive and Application are based on commercial operating systems. Their part related with the operating system is encapsulated in a class definition so that platform-independent modularization is possible through change of this part. The other modules are all based on OSS.

4.5 TRX Software The TRX software runs on the single-chip microcomputer of the RFCM board, able to be downloaded from the background. It is the monitoring center of RFS and implements the communications between EBDS and RFS. Its major functions are as follows:

1. Signaling reception, processing, generation and transmission

The RFCM chip reads the CCM signaling data through the FPGA interrupt, analyzes the signaling contents, sets appropriate flag bits or assigns specific parameter values for them to be processed by the main program.

OSS

S_CEC Alarm proxy

CEM

Riop PAM DmpApplicationDrive

PSOS or the VxWorks commercial operating system



It can generate signaling messages based on the detected status information of the functional modules and send them to the CCM. These signaling data are sent to and processed by FPGA.

2. Controlling and monitoring the functional units in RFS via the IIC bus

The RFCM chip, as the main node of the IIC bus, controls the bus operations. It controls and monitors the relevant functional units by reading from or writing to the interface devices on the bus, such as IIC I/O expansion, EEPROM and IIC ADC/DAC. The details are as follows: • TRX configuration, status detection and functional control

FS configuration and PLL state detection

EEPROM data query Control of the special-purpose attenuators (TPTL, Blossoming & Wilting and cell breathing) in the TRX • HPA enable/disable control

• HPA status check

• RFE status check: VSWR alarm, LNA fault detection and forward transmitting power monitoring in the mode of interrupt or regular query.

3. RFCM monitors the entire RFS and reports the alarms produced by its modules, including: • HPA over-power alarm

• HPA over-temperature alarm

• HPA component failure alarm

• HPA VSWR alarm

• RFE VSWR alarm

• LNA over-/under-current alarm of RFE Rx signals

• I2C component alarm

4. Status information report

The RFCM software may report the following status parameters to the RCM software: • RFE transmitting power

• RSSI values of the main and diversity receiving links

• Forward TX attenuation values

• Reverse RX attenuation values (main & diversity)

• The instantaneous error, average and integral values of I2+Q2

5. Remote software download

The TRX software can be downloaded from the background remotely, thus providing a high-speed reliable means for future board software upgrading.


5 NETWORKING & CONFIGURATION

5.1 BTS Networking The BTS networking can be one of the followings: star networking, chain networking and hybrid networking.

5.1.1 Star Networking

BSC

BTS0

BTS1

BTS2

BTS3

Fig. 25 Star Networking

In star networking, several BTSs are directly connected to one BSC via several E1 PCM links. Due to the simplicity of this mode, both maintenance and engineering can be easily implemented. Since the signals are transmitted through fewer intermediate links along the path, the reliability of transmission is quite high. This is also the mode commonly adopted at densely populated areas.

5.1.2 Chain Networking

Chain networking is also applicable for a site with multiple BTSs. In this mode, there are relatively more intermediate nodes along the path of signals, and the transmission reliability is therefore much lower. This mode will be a good choice for a ribbon-like area sparsely populated, for it can reduce investment in transmission equipment.

In practice, due to the dispersibility of the sites, a variety of transmission devices are usually applied as repeaters to connect the BTSs to the BSC. Among them, those typical ones are



microwave transmission, fiber transmission, HDSL transmission and coaxial cable transmission devices.

BSCBTS0 BTS1 BTS2

Fig. 26 Chain Networking

5.1.3 Hybrid Networking

BSC

BTS0 BTS1 BTS2

BTS3

BTS4

Fig. 27 Hybrid Networking

5.1.4 BTS+Remote RF Station

BTS

LFM RFM RFM

Remote RF station

Optical

Fig. 28 Extended mode of RF part

5.2 BTS Configuration

5.2.1 Key Indices

In the BTS configuration, the following indices are very important:



• Flexible 6-carrier*sector configuration of a single rack: 2-carrier 3-sector or 1-carrier 6-sector

• Common networking mode: star networking

• Maximum number of reverse channels: 384

• Four Types of channel element boards supported: CHM32, CHM64, CHM96 and CHM128.

5.2.2 Single-Carrier Configuration

The single-carrier configuration of one BTS rack is shown in Fig.29.

Fig. 29 Single-carrier Configuration of One BTS Rack

RFE-DIV RFE-DUP RFE-DIV RFE-DUP RFE-DIV RFE-DUP

HPA HPA HPA BTM

PSMD PPM PPM PPM PSMC PSMC

TRX TRX TRX FDM

G P S T M

TCM

G P S T M

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

P S M B

CHM

CHM

RFIM

SAM

CCM

CCM

CDSU

PSMB



5.2.3 Dual-Carrier Configuration

The dual-carrier configuration of one BTS rack is shown in Fig.30.

Fig. 30 Dual-Carrier Configuration of One BTS Rack

5.2.4 Site Types

By the allocation of frequency resources and cell planning, a cellular mobile network can be divided into a number of cells that are adjacent to one another, as shown in Fig.31.

RFE-DUP RFE-DUP RFE-DUP RFE-DUP RFE-DUP RFE-DUP

HPA HPA HPA BTM HPA HPA HPA

PSMD PPM PPM PPM PPM PPM PSMC PSMC

TRX TRX TRX FDM

G P S T M

TCM

G P S T M

TRX TRX TRX

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

P S M B

CHM

CHM

RFIM

SAM

CCM

CCM

CDSU

CHM

CHM

RFIM

PSMB



Cell1

Cell3

Cell4

Cell2

Cell5

Cell6

Cell7

Cell9

Cell8

A

B

Fig. 31 Cells of a Mobile Network

Each cell is covered by a number of radio channels. When the omnidirectional antennae are adopted, each cell is likely to have one base station in its center position (as shown in Fig. A). When the directional antennae are adopted, each base station is positioned in the joint of three cells (as shown in Fig. B), covering the three adjacent cells at the same time. Actually, the base station will consist of at least three TRXs. That is, a base station that uses an omnidirectional antenna covers only one cell, yet a base station that uses a directional antenna covers three cells at the same time.

Accordingly, the sites can be divided into two types: O-type and S-type. An O-type site refers to an omnidirectional cell, that is, all the carriers provided by this O-type site serve this cell only. An S-type site refers to sectorized cells, usually three sectors. Each sector can support multiple TRXs at the same time. For the models of an O-type site and an S-type site, as shown in Fig.32.

O-type S-type

Fig. 32 Two Site Types

5.2.5 Recommended Site Types and Number of Traffic Channels

The recommended site types and number of traffic channels are shown in Table 10.

Table 10 Recommended Site Types and Number of Traffic Channels



Recommended Site Type

Recommended Number of Traffic Channels/Sector

Typical Number of Traffic

Channels/Sector

Typical Site Types and Total Number of Reverse

Channels O1 25-46 35 O1-64

S111 35-46 35 S111-160

S222 50-90 66 S222-320

Note: O1 is recommended for medium- to small-sized, sparsely populated cities. It is an indoor model that has strict requirements on the equipment room. M1 is recommended for medium- to small-sized, sparsely-populated cities (or for further coverage).

It is of a small size and can be installed either indoors or outdoors. Since it does not have strict requirements on the equipment room, it is a more economical solution.

5.2.6 Board Configurations under Different Site Types

After the site type is determined, the number of boards can be determined accordingly, except the CHMs, which may vary with the specific conditions. For the board configurations under different site types, see Table 11.

Table 11 Site Types and Number of Boards

No. Name Model O1 S1 S11 S111 O2 S2 S22 S222 A. BDS shelf

0 CHM CHM32

1 CHM CHM64

2 RFIM RFIM 1 1 1 1 2 2 2 2

3 SAM SAM 1 1 1 1 1 1 1 1

4 CCM CCM 2 2 2 2 2 2 2 2

5 CDSU BTS-CDSU 1 1 1 1 1 1 1 1

6 HIRS_BDS

backplane

HIRS_BDS

backplane 1 1 1 1 1 1 1 1

7 Power board PSMB 2 2 2 2 2 2 2 2

B. TRX shelf

8 TRX module Tx, Rx, CIQU,

FS, RFCM 1 1 2 3 2 2 4 6

9 FDM FDM 1 1 1 1 1 1 1 1

10 TCM TCM 1 1 1 1 1 1 1 1

11 GPSR GPSTM 1 1 1 1 1 1 1 1

12 TRX

backplane 1 1 1 1 1 1 1 1

C. PPM shelf

13 RF power

board (+27V) PPM 2 2 2 3 2 2 4 5



No. Name Model O1 S1 S11 S111 O2 S2 S22 S222

14 Power board

(±12V) PSMC 2 2 2 2 2 2 2 2

15

Power

distribution

board

PSMD 1 1 1 1 1 1 1 1

16 PPM

backplane 1 1 1 1 1 1 1 1

D. HPA shelf

17 HPA HPA 1 1 2 3 2 2 4 6

E. RFE shelf

18 RFE

(Duplexer) RFE-DUP 1 1 2 3 2 2 4 6

19 FE (Receiver) RFE-DIV 1 1 2 3 0 0 0 0

20 RFE backplane 1 1 1 1 1 1 1 1

F. Antenna

feeder

subsystem

21

GPS antennae,

feeders and

others

1 1 1 1 1 1 1 1


APPENDIX A: ABBREVIATION

Table 12 Abbreviation in this document

Abbreviation Full Name AGC Automatic Gain Control AUC Authentication Center BSC Base Station Controller BSS Base Staion System BTM BTS Test Module BTS Base Transceiver Station CCM Communication Control Module CE Channel Element CES Channel Element Subsystem CHM Channel Processing Module COM Contribute Module CSM Code-site Module DBS Data Base Subsystem DSM Digital Service Module DUP Duplexer EBDS_IP IP Enhanced Baseband Digital Subsystem EV-DO Evolution Data Only FA Foreign Agent FDM Frequency Distribution Module FE Fast Ethernet FER Frame Error Rate F-SCH Forward Supplementary Channel GPSTM GPS Timing Module HDLC High-level Data Link Control HLR Home Location Register HPA High Power Amplifier I/O Input/Output LFM Local Fiber Module LNA Low Noise Amplifier MS Mobile Station MSC Mobile Switch Center MTBCF Mean Time Between Critical Failures MTBF Mean Time Between Failures MTTR Mean Time To Recovery NMS Network Management System OMS Operation & Maintenance Subsystem OSS Operating System Subsystem



Abbreviation Full Name PCF Packet Control Function PDSN Packet Data Serving Node PS Power Subsystem RF Radio Frequency RFCM Radio Frequency Control Module RFE Radio Front End RFM Remote Fiber Module RFS Radio Frequency Subsystem RIM Radio Interface Module SAM Site Alarm Module SDH Synchronous Digital Hirerachy SIM System Interface Module SNM SDH Network Module SPS Service Processing Subsystem TCM Time Control Module TFS Timing & Frequency Subsystem TOD Time Of Date

zxc 10 bts

Documents