Gsm Overview

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BSS OVERVIEW 7th -Mar-2014

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

GSM OVERVIEW

Global system for mobile communication (GSM). The GSM network is divided into three major

systems: Switching System (SS): MSC,HLR,VLR,EIR &

AUC,GMSC. Base station system (BSS): BSC , BTS & MS. Operation and support system (OSS):OMC BSC Hardware Structure.


Switching System: The switching system (SS) is responsible for performing call processing and subscriber-related

functions. The switching system includes the following functional units. Home location register (HLR) —The HLR is a database used for storage and management of

subscriptions. The HLR is considered the most important database, as it stores permanent data about subscribers, including a subscriber's service profile, location information, and activity status. When an individual buys a subscription from one of the PCS operators, he or she is registered in the HLR of that operator.

Mobile services switching center (MSC) —The MSC performs the telephony switching functions of the system. It controls calls to and from other telephone and data systems. It also performs such functions as toll ticketing, network interfacing, common channel signaling, and others.

Visitor location register (VLR) —The VLR is a database that contains temporary information about subscribers that is needed by the MSC in order to service visiting subscribers. The VLR is always integrated with the MSC. When a mobile station roams into a new MSC area, the VLR connected to that MSC will request data about the mobile station from the HLR. Later, if the mobile station makes a call, the VLR will have the information needed for call setup without having to interrogate the HLR each time.

Authentication center (AUC) —A unit called the AUC provides authentication and encryption parameters that verify the user's identity and ensure the confidentiality of each call. The AUC protects network operators from different types of fraud found in today's cellular world.

Equipment identity register (EIR) —The EIR is a database that contains information about the identity of mobile equipment that prevents calls from stolen, unauthorized, or defective mobile stations. The AUC and EIR are implemented as stand-alone nodes or as a combined AUC/EIR node.


Base Station System (BSS) & OSS

All radio-related functions are performed in the BSS, which consists of base station controllers (BSCs) and the base transceiver stations (BTSs).

BSC —The BSC provides all the control functions and physical links between the MSC and BTS. It is a high-capacity switch that provides functions such as handover, cell configuration data, and control of radio frequency (RF) power levels in base transceiver stations. A number of BSCs are served by an MSC.

BTS —The BTS handles the radio interface to the mobile station. The BTS is the radio equipment (transceivers and antennas) needed to service each cell in the network. A group of BTSs are controlled by a BSC.

The Operation and Support System: The operations and maintenance center (OMC) is connected to all equipment in the switching

system and to the BSC. The implementation of OMC is called the operation and support system (OSS). The OSS is the functional entity from which the network operator monitors and controls the system. The purpose of OSS is to offer the customer cost-effective support for centralized, regional, and local operational and maintenance activities that are required for a GSM network. An important function of OSS is to provide a network overview and support the maintenance activities of different operation and maintenance organizations.

HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

Huawei Confidential

Security Level:

英文标题 :40-47pt 副标题 :26-30pt字体颜色 : 反白内部使用字体 :

FrutigerNext LT Medium外部使用字体 : Arial

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2009/06

BSC6900 Hardware Structure

TSD Wireless Product Service Department-GBSS


BSC6900 Capacity Index

BSC6900 GSM only

Item 1MPS+1TCS 1MPS+1EPS+2TCS 1MPS+2EPS+2TCS

Number of cabinets

2 2 2

BHCA(K) 1750 3500 5250

Traffic volume （ Erl ）

6500 13000 19500

Number of TRXs 1024 2048 3072

Number of active PDCHs （ MCS-9 ）

4096 8192 12288

Typical configuration specifications of the BSC6900 GSM(BM/TC separated and Abis over non-IP R11 board)


BSC6900 Hardware-Cabinet The BSC6900 uses the Huawei N68E-22 cabinet and the Huawei

N68-21-N cabinet. The two models of cabinets have the same appearance.N68E-22 is

divided into a single-door cabinet or a double-door cabinet.

Item SpecificationHeight of the available space

46U

Weight Empty cabinet≤100 kg

Cabinet in full configuration≤300 kg

Input voltage range

-40 V to -57 V


BSC6900 Hardware--Cabinet The BSC6900 GSM cabinet is classified

into main processing rack (MPR), extended processing rack (EPR), and transcoder rack (TCR).


BSC6900 Hardware--Subrack The BSC6900 GSM subrack has a standard width of 19

inches. The height of each subrack is 12 U. The boards are installed on the front and rear sides of the backplane, which is positioned in the center of the subrack.

A subrack provides 28 slots. The slots on the front of the subrack are numbered from 0 to 13, and those on the rear are numbered from 14 to 27.


Typical Configuration Parameter Description


Board——TNUa

Port Function Matching connector

TDM0 ～ 5 TDM high-speed serial port, used to connect the TNUaS between subracks

DB14

GTNU

PARC

RUNALM

ACT

TNM

5TN

M4

TNM

0TN

M1

TNM

2TN

M3

The TNUa is the TDM switching unit in the BSC6900.

The active and standby TNUa are inserted in slot 4 and slot 5. The TNUa board performs the TDM switching function, which is the TDM switching center of the system.

The TNUa has the following functions:

Providing 128 K ×128 K TDM switching

Allocating TDM network resources, establishing, and releasing radio links


Board——SCUa

Port Function MatchingEHT0 ～ 9 10M/100M/1000M Ethernet ports, used to connect subracks RJ45EHT10 ～11

10M/100M/1000M Ethernet ports, used to connect GBAM (Only the main subrack is connected with the GBAM)

RJ45

COM Debugging port RJ45

CLKIN Clock source port, used to receive the 8 kHz clock signals from the panel of the GGCU

RJ45

TESTOUT Clock test signal port, used to output clock test signals SMB connector

The SCUa is the switching control unit in the BSC6900. The active and standby SCUa are inserted in slot 6 and 7.

The SCUa board provides maintenance management of the subrack and GE switching platform for the subrack.

The SCUa has the following functions: Performing maintenance management of the subrack

Providing a GE platform for the subrack

Providing clock information for the other boards in the same subrack except the GCUa

ACTLINK

ACTLINK

ACTLINK


Service Processing Subsystem Hardware Involved

XPUa/b board, SPUa/b board, DPUa/b/c/d/e board Board Specification

XPU/SPU is the signaling processing unit SPU board can process GSM/UMTS signaling panel, XPU board can

process GSM signaling panel SPU board Works for BSC6900 GU mode XPU board Works for BSC6900 GSM only mode The postfix of “a” board contain 4 logic subsystem, and the postfix of

“b” board contain 8 logic subsystem Services Process Unit DPUa/b/c/d/e


Board Introduction-XPU/SPU Loaded with different software, the XPUa board is functionally

divided into main control XPUa board and non-main control

XPUa board.

XPUa

PARC

RUNALM

ACT

10/1

00/1

000B

AS

E-T

ACTLINK

0

1

2

3

The 0 subsystem of main control XPU/SPU

board is MPU, used to manage the user panel

and signaling plane resources within the

subrack and process the signaling. The subsystem of non-main control XPU/SPU

board is CPU, used to process the signaling. For GSM Only mode, one MPU for the system

is enough. If the system upgrade to GU mode,

one MPU should for one subrack.

Main control XPUa

Non-Main control XPUa


Board Introduction——DPUc Function

DPUc process CS services and perform the voice coding and decoding function. It works as subrack system pool mode.

Provides the speech format conversion and data forwarding functions when configured in BM subrack.

Provides the Tandem Free Operation (TFO) function

Provides the voice enhancement function

Detects voice faults automatically

DPUd board works for GSM services.

DPUa

PARC

RUNALM

ACT


Board introduction——DPUd Function

The DPUd is the Data Processing Unit for PS services. It can be installed in slots 8–11 in MPS and 8-27 in EPS ， it processes the packet services for the BSC.

Each DPUd supports 1024 activated PDCHs at the same time, and all the PDCHs support MSC-9 coding.

Packet links processing function.

PS fault self-detection.

DPUd board works for GSM services.

DPUa

PARC

RUNALM

ACT


Subsystems Five: Interface Board System

Board

Type

Physical Board

Board specification Scene

EIUa Transmits, receives, encodes, and decodes 32 E1s/T1s. GSM Only

OIUa Provides one STM-1 port for TDM transmission GSM Only 、 GU

Old Boards

FG2a Provides eight channels over FE ports or two channels over GE electrical ports

GSM Only 、 GU

GOUa Provides two channels over GE optical ports GSM Only 、 GU

PEUa Provides 32 channels of E1s/T1s for HDLC transmissionExtracts line clock signals

GSM Only 、 GU

Multi-kernel Boards

FG2c Provides 12 channels over FE ports or four channels over GE electrical ports

GSM Only 、 GU

GOUc Provides four channels over GE optical ports GSM Only 、 GUPOUc Provides four channels over channelized optical STM-1/OC-

3 ports based on IP protocol

Extracts line clock signals

GSM Only 、 GU


Co-Transmission for the Interface BoardPhysical

BoardFunction Interface Board Sharing

Iub Iu(Iur/IuCS/IuPS)

Abis A Ater Gb

FG2a IP Iub/Iu Co-Interface board Abis/A Co-Interface board 　 Gb Separated GOUa IP Iub/Iu Co-Interface board Abis/A Co-Interace board 　 Gb Separated AOUc ATM Iub/Iu Co-Interface board 　　　　UOIc ATM Iub/Iu Co-Interface board 　　　　

IP Iub/Iu/Abis/A(Ater) 共接口板　POUc TDM+ HDLC 　　 Abis/A(Ater)/Gb(Pb) Co-Interface board

IP Iub/Iu/Abis/A(Ater) Co-Interface board 　FG2c IP Iub/Iu/Abis/A(Ater)/Gb(Pb) Co-Interface boardGOUc IP Iub/Iu/Abis/A(Ater)/Gb(Pb) Co-Interface boardEIUa Abis TDM 　　　　　　

Ater TDM 　　　　　　Pb TDM 　　　　　　A TDM 　　　　　　

OIUa Abis TDM 　　　　　　Ater TDM 　　　　　　Pb TDM 　　　　　　A TDM 　　　　　　


Board Introdction-FG2c The FG2c board supports IP over Ethernet transmission.

The FG2c board performs the following functions: Provides 12 channels over FE ports or four channels over GE

electrical ports

Provides the link aggregation function at the MAC layer

Provides the routing-based backup and load sharing

Supports the transmission of data over all its Ethernet ports on the

basis of the synchronized clock signals

Supports the Abis 、 A 、 Gb 、 Iu 、 Iub interfacesPort Function Connector type

10/100BASE-T 10M/100M Ethernet ports, used to transmit 10/100M signals

RJ45

10/100/1000BASE-T

10M/100M/1000M Ethernet ports, used to transmit 10/100/1000M signals

RJ45

2M0 、 2M1 Port for 2 MHz clock signal outputs male connector


Board Introduction-GOUc As an optical interface board, the GOUc board supports IP

over Ethernet transmission.

The GOUc board performs the following functions: Provides four channels over GE optical ports

Provides the routing-based backup and load sharing

Extracts line clock signals

Supports the Abis, A, and Gb,Iu, Iub interfaces

Port Function Connector Type

RX Optical port, used to transmit and receive optical signals. TX refers to the transmitting optical port, and RX refers to the receiving optical port.

LC/PC

TX

2M0 、 2M1 Port for 2 MHz clock signal outputs SMB male connector


Board Introduction-POUc As an interface board, the POUc board supports IP over

channelized STM-1/OC-3 transmission. The POUc board performs the following functions:

Provides four channels over channelized optical STM-1/OC-3 ports based

on IP protocol Supports the PPP function Extracts line clock signals Provides the Automatic Protection Switching (APS) function between the

active and standby POUc boards Supports the A, Abis, Gb, Ater,Pb, Iu, Iub interfaces

Port Function Connector type

RX Optical port, used to transmit and receive optical signals. TX refers to the transmitting optical port, and RX refers to the receiving optical port.

LC/PC

TX

2M0

2M1

Output ports for clock signals. These ports are used to transmit the 2 MHz line clock signals to the GCUa/GCGa board. The clock signals are extracted from upper-level devices and serve as the clock sources of the BSC6900 system.

SMB male connector


Subsystems Four: Clock Subsystem Clock Source

Bits clock Line clock GPS

Reference Clock for the MPS or EPS The reference clocks are provided by the GCUa. The reference clocks

generate 8kHz clock signals through the GCUa. MPS: The clock signals are sent to the SCUa in the MPSa subrack through

the backplane. Then, the clock signals are sent to other boards in the same subrack.

EPS: The clock signals are sent to the SCUa board in the EPSa subrack through the clock cable. Then, the signals are sent to other boards through

the backplane. Reference Clock for the TCS

Each TCS extracts line clock from the A interface. The line clock is processed through A interface panel and then generates 8 KHz clock signals.

The clock signals are sent to the SCUa in the subrack through the backplane. Then the clock signals are sent to other boards in the same subrack.


Board——GCUa

GGCU

PARC

RUNALMACT

8

9

COM0

COM1

0

1

2

3

4

5

6

7

CLK

OU

TTE

STI

N

TES

TOU

T

CLK

LIN

1

CLK

LIN

0

The GCUa is the general clock unit in the BSC6900. The active and standby GCUa are configured in slots 12 and 13 in the MPS. The GGCU board provides synchronous timing signals for the system

The GCUa has the following functions: Generating and keeping synchronous clock signals

Keeping the consistency of synchronization information output from the active and standby GCUa

Port Function Connector type

ATN-IN Reserved SMA male connector

CLKOUT0~9Ports for transmitting synchronization clock signals. The ten ports are used to transmit the 8 kHz clock signals to the CLKIN port on the panel of the SCUa board.

RJ45

COM0,COM1 Reserved RJ45

TESTOUT Reserved SMB male connector

TESTIN Input port for testing external clock signals SMB male connector

CLKIN0-1Synchronization clock input port, used to receive the 2.048 MHz clock signals or 2.048 Mbit/s code stream signals

SMB male connector


Board Introduction —— OMU The OMUa board works as a bridge for the communication

between the WebLMT and the other boards in the BSC6900. Function

Performing the configuration management, performance management, fault management, security management, and loading management functions for the system

To control the communication between the LMT/M2000 and the SCUa board of the BSC6900

(1) Captive screw (2) Shielding finger (3) Ejector lever (4) LED (RUN)

(5) LED (ALM) (6) LED (ACT) (7) Button (RESET) (8) Button (SHUTDOWN)

(9) USB port (10) Ethernet port (ETH0)

(11) Ethernet port (ETH1)

(12) Ethernet port (ETH2)

(13) COM port (14) VGA port (15) LED (HD) (16) LED(OFFLINE)

(17) Hard disk (18) Screw for fixing the hard disk


Clock Synchronization Interconnection The connection of the GCUa of the main

subrack and the extension subrack is shown:

The active and standby GCUa output 10-way signal channel respectively. A signal channel of an active GCUa and that of a standby GCUa are integrated through the Y-shaped cable.

Any of component including GCUa, Y-shaped cable, and SCUa is faulty, the system clock still can work normally.


Signaling Flow on the Gb Interface Gb Over IP

the signaling processing board processes the signaling according to the NS and BSSGP protocols. Then, the signaling is transmitted to the Gb interface board through the SCUa board.

The Gb interface board processes the signaling according to the IP or FR protocol. Then, the signaling is transmitted to the SGSN over the Gb interface.


OM Signal Flow


Specification of the Board XPUa/XPUb

350TRX/XPUa 640TRX/XPUb No. of XPUa=TRX No./350TRX No. of XPUb=TRX No./640TRX For GSM only system, we can be configured just one main control XPU,

which configured as RGCP The control panel optimized for BSC6900, XPUa/XPUb can congfigured in

different subrack with Transcode board and interface board averagely.


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Gsm Overview

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