PCU V300R005 System Description

M900/M1800 Packet Control Unit System Description

i

PCU System Description

Huawei Technologies Co., L


i

Table of Contents

Chapter 1 Introduction ............................................................................................................1 1.1 Development of Mobile Communication Network ............................................................1 1.2 Huawei GPRS Solution for Mobile Communication Network ............................................1 1.3 Significance of GPRS for Network Operators ..................................................................2 1.4 Significance of GPRS for Mobile Subscribers .................................................................3 1.5 Position of PCU in GPRS System ..................................................................................4

Chapter 2 Product Features ....................................................................................................6 2.1 Large Capacity and High Processing Capability..............................................................6 2.2 Flexible Configuration ...................................................................................................6 2.3 G-Abis Interface Solution ..............................................................................................6 2.4 CS Dynamic Adjustment Algorithm ................................................................................6 2.5 MCS Dynamic Adjustment Algorithm..............................................................................6 2.6 PDCH Dynamic Conversion ..........................................................................................6 2.7 Multiple Networking Modes............................................................................................7 2.8 Supporting the MML Operation......................................................................................7 2.9 General OMC System for GSM/GPRS and Standard NM Interface ..................................7 2.10 Reliability Design ........................................................................................................7 2.11 Signaling Tracing on Both Um and Gb Interfaces ..........................................................7

Chapter 3 System Architecture ...............................................................................................8 3.1 Product Appearance .....................................................................................................8

3.1.1 Cabinet Features ................................................................................................8 3.1.2 Cabinet Configuration..........................................................................................9

3.2 Hardware Architecture ..................................................................................................9 3.2.1 POMU.............................................................................................................. 10 3.2.2 HSC................................................................................................................. 10 3.2.3 RPPU............................................................................................................... 11 3.2.4 L2PU ............................................................................................................... 11 3.2.5 PMC ................................................................................................................ 11

3.3 Software Architecture.................................................................................................. 11

Chapter 4 Function and Application...................................................................................... 13 4.1 Service Processing Function ....................................................................................... 13

4.1.1 Packet Channel Combinations Supported........................................................... 13 4.1.2 System Information Supported........................................................................... 13 4.1.3 MS Classes Supported...................................................................................... 13 4.1.4 MAC Modes Supported ..................................................................................... 13 4.1.5 RLC Modes Supported ...................................................................................... 13 4.1.6 Coding Schemes Supported .............................................................................. 14


ii

4.1.7 Network Control Modes Supported..................................................................... 14 4.1.8 Network Operation Modes Supported................................................................. 14 4.1.9 QoS Supported ................................................................................................. 14 4.1.10 Accesses Supported ....................................................................................... 14 4.1.11 Assignments Supported................................................................................... 14 4.1.12 Pagings Supported.......................................................................................... 15 4.1.13 TA Update...................................................................................................... 15 4.1.14 Measurement Report ....................................................................................... 15 4.1.15 Power Control ................................................................................................. 15 4.1.16 Traffic Controls Supported ............................................................................... 15 4.1.17 Dynamic Conversion between TCH and PDCH. ................................................ 15 4.1.18 PCCCH Access Function................................................................................. 15 4.1.19 Modulation and Coding Schemes Supported .................................................... 16 4.1.20 Link Quality Control Supported......................................................................... 16 4.1.21 Multiplexing of GPRS and EGPRS MSs............................................................ 16

4.2 Networking ................................................................................................................. 17 4.2.1 Networking Mode I............................................................................................ 17 4.2.2 Networking Mode II ........................................................................................... 17 4.2.3 Networking Mode III .......................................................................................... 18

Chapter 5 Operation and Maintenance .................................................................................. 19 5.1 Overview.................................................................................................................... 19 5.2 Alarm Management .................................................................................................... 19

5.2.1 Features of Alarm Management ......................................................................... 19 5.2.2 Alarm Processing.............................................................................................. 20

5.3 Performance Measurement Management ..................................................................... 20 5.3.1 Measurement Task Management ....................................................................... 20 5.3.2 Measurement Result Management ..................................................................... 21

5.4 Maintenance Management .......................................................................................... 21 5.4.1 Overall Structure ............................................................................................... 21 5.4.2 Main Features .................................................................................................. 22

5.5 Data Configuration ...................................................................................................... 22

Chapter 6 Reliability .............................................................................................................. 23 6.1 System Protection Mechanism..................................................................................... 23 6.2 Error Tolerance .......................................................................................................... 23 6.3 MTBF and MTTR ........................................................................................................ 23 6.4 Data Security.............................................................................................................. 23 6.5 Operation Security ...................................................................................................... 24

Chapter 7 Technical Indices.................................................................................................. 25 7.1 Processing Capability.................................................................................................. 25 7.2 Overall Technical Indices ............................................................................................ 25 7.3 Structural Indices ........................................................................................................ 26 7.4 Electric Indices ........................................................................................................... 26


iii

7.5 System Operation Environment ................................................................................... 26 7.6 Other Indices .............................................................................................................. 27

Appendix A Technical Specifications and Standards............................................................ 28

Appendix B Abbreviations .................................................................................................... 29


1

Chapter 1 Introduction

1.1 Development of Mobile Communication Network

The development of public mobile communication network has undergone two generations. From the 1980s, the first generation analogue mobile communication system employing the FDMA (Frequency Division Multiple Access) began to offer only the speech service. The second generation digital mobile communication system was born in the 1990s. It consisted of many standards like GSM and IS-95. Focusing on speech service, it offered low speed circuit data service as well. Now there has been the third generation of mobile communication service, primarily to meet the demand for high-speed mobile data communication.

The third generation mobile communication system is still several years away from its commercial application. The great difference between the second and third generations and the huge investment that has been made in the second generation system make it a consensus that there should be a smooth transition to the third generation. Based on the GSM, the GPRS solution is the major one that complies with the strategy of smooth transition.

1.2 Huawei GPRS Solution for Mobile Communication Network

The M900/M1800 GPRS is a general packet radio service system developed by Huawei on the basis of its years of experience in the research of mobile and data communication products. It is commercialized simultaneously with other leading international manufacturers. Huawei provides not only the GPRS equipment, but also the customized network solution that is easy to maintain, operate and manage, so as to satisfy the needs and network features of different operators. The differentiated services and flexible charging modes catering for different subscriber groups can ensure operators’ profits. Figure 1-1 is a diagram of typical GPRS networking.


2

R

BSS

MSC/VLR

PSTN

SS7 Network

EIRHLR/AUC SMS-GMSC/IWMSC

FirewallFirewall

Router

Router

Server

Server

SGSN

other PLMN

GGSNBGGPRSBackboneIP based

Data Network(Internet)

Billing Center

MTTE

PCU

MSSCP

GMLC

R

R

R

CGDNS ServerR

PCU: Packet Control Unit SGSN: Serving GPRS Support Node

GGSN: Gateway GPRS Support Node CG: Charging Gateway

BG: Border Gateway DNS: Domain Name System

BSS: Base Station Subsystem MT: Mobile Terminal

MS: Mobile Station TE: Terminal Equipment

SCP: Service Control Point GMLC: Gateway Mobile Location Center

EIR: Equipment Identity Register HLR/AuC: Home Location Register/Authentication Center

SMS-GMSC/IWMSC: Short Message Service-Gateway MSC / InterWorking MSC

MSC/VLR: Mobile Switching Center/Visitor Location Register

Figure 1-1 GPRS networking

1.3 Significance of GPRS for Network Operators

GPRS provides operators with a packet switching network that enables higher efficiency of data transmission, and as a result, brings new opportunities for operators. Significance of M900/M1800 GPRS system for operators is mainly presented in the following aspects:

I. Making full use of the existing GSM network, small investments and quick rewarding

The M900/M1800 GPRS solution takes into consideration on how to protect the existing investments and obtain maximum benefits for operators. As GPRS can share the BTS system of GSM, mobile operators can quickly enter the Internet service market with small investments at the initial stage of network operations to provide rich packet data services to subscribers. Afterwards, subsequent investments can be added according to service needs and market developing trends so that investment risks can be minimized.


3

II. Increasing income and competitive edge for operators with the provision of various services

In the past few years, the digital cellular mobile telecommunication system has been greatly developed. The rapid increase of subscriber number brings huge benefits for mobile operators.

When the subscriber number reaches a certain level, the increase speed will inevitably slow down. In this situation, to increase their operation income and obtain sustainable developments, the operators shall consider providing more new services (such as non-speech services) to attract more subscribers.

GPRS provides subscriber with the convenience to obtain needed information at any time and at any place. Users can use it to receive/send E-mails, visit Internet, or exercise electronic business activities in moving state. As GPRS provides only the bearer functions on IP layer, operators or even users can customize their own value-added services, such as remote control, E-shopping, vehicle dispatching, news browse, and mobile multi-media. In theory, all service types available in the fixed Internet are also available in GPRS networks.

In the years to come, further developments of Internet will have great influences on people’s working and daily life, and Internet services will be more widely used. This will be a good foundation for the development of GPRS services.

III. Evolution from GPRS system to 3G that protects operators’ investments

As a TDMA mode 2G system, GSM is at present mainly used for speech services. With further developments of mobile communications and data communications, data services will have larger proportion. Therefore, an important issue presented before the operators is how to update the existing GSM infrastructure so as to make it capable of providing packet data services.

GPRS provides the solution to update the existing GSM system with small investments to enable it to cater to future packet service developments. By now, the evolution path from GSM to 3G is very clear, that is, to smoothly transit to 3G via the GPRS stage. Only in this way, huge investments of operators in the GSM networks can be protected, and they can share the huge benefits of the data services with only a much smaller risk taken.

1.4 Significance of GPRS for Mobile Subscribers

For mobile subscribers, GPRS is a bridge between the mobile system and Internet. Subscribers can enjoy data services via mobile terminals more conveniently. Advantages brought by GPRS for mobile subscribers are mainly as follows:

I. Quick access to internet

GPRS system enables mobile subscribers to access Internet as quick as they were using LAN. As the packet mode is adopted, the subscribers, instead of having to establish connections each time when they want to send data, will be in connected state all the time. That is to say, the subscriber can keep the online state. At present, even the most commonly used Modem dial-up Internet access mode needs a dial-up connection process before logging on Internet, which takes quite a long time.


4

II. Higher trasfer rate

GPRS system can provide subscribers with higher transfer rate. The maximum data transfer rate available for the GSM users is 9.6kbit/s, much lower than what they can enjoy with dial-up Internet access mode. This disadvantage greatly limits the usage of data services by mobile subscribers. With GPRS, however, a subscriber can simultaneously enjoy 8 channels for data transmission, and the highest speed in the current CS -2 can reach 107kbit/s. In the future, after the BTS software is upgraded to support CS-3 and CS-4, the rate in theory can be up to 171.2kbit/s. This speed is higher than that of the ordinary dial-up Internet access mode. Therefore, after the GPRS network starts operating, mobile subscribers can enjoy high-speed Internet services with their mobile stations.

III. More reasonable charge

GPRS system can charge subscribers by their actual data transmission volume, in which case, the subscribers need not pay while browsing web sites. This method of charging according to subscriber’s actual usage of network is obviously an advantage for subscribers.

1.5 Position of PCU in GPRS System

BTS

BTS

BTS

BSC

BSC

PCU SGSN

BSS

R

OMC

G-Abis

G- Abis

G- Abis

Pb/G- Abis

Gb

O

Pb/G-Abis

Figure 1-2 The position of the PCU in the GPRS system

Being an important component of the GPRS network, the PCU (Packet Control Unit), together with the software-upgraded BSC, form the GPRS BSS to implement the packet service processing and management of the packet radio channel resources on the BSS side.

As shown in Figure 1-2, the PCU communicates with the SGSN through the Gb interface to implement the functions of packet data transmission, traffic control, mobility management, etc. It is also connected with the BSC via the Pb interface to manage the resources shared by the PCU and the BSC, such as the cell, the packet channel, the E1 trunk cable and system information, etc. It is connected with the BTS via the G-Abis


5

interface to implement the functions of block synchronization, transmission of packet signaling, packet data and inband signaling. Via the O interface, it is connected with the OMC (Operation and Maintenance Center) system as well.

& Note:

There is no direct trunk cable connecting the PCU and the BTS. The G-Abis interface is physically realized

in the way of transparent transmission by the BSC.

The Gb interface of Huawei M900/M1800 PCU is standard interface that enables the interconnection between Huawei PCU and the SGSN equipment of other manufacturers.


6

Chapter 2 Product Features

2.1 Large Capacity and High Processing Capability.

The processing capability of PCU with fully-configured single processing frame is 10000 pps. It can activate 1080 GPRS PDCHs (Packet Data Channels) or 900 EGPRS PDCHs simultaneously.

2.2 Flexible Configuration

With the modular design employed, PCU capacity can be smoothly expanded by adding modules, which is both cost effective and non-influential to the existing services.

2.3 G-Abis Interface Solution

Huawei introduces self-defined G-TRAU frame structure via the G-Abis interface, so that the PCU and BTS can cooperate to serve as the BSS of GPRS, with the smallest change to the BSC module that originally provides circuit switching.

PCU supports satellite transmission on G-Abis interface between PCU and BTS, the maximum delay allowed on G-Abis interface is 800 ms.

2.4 CS Dynamic Adjustment Algorithm

According to the radio transmission quality in the air, the system can dynamically adjust the channel Coding Schemes (CS -1, CS-2, CS-3 and CS-4) to make full use of radio resources and increase the transmission rate on the condition of guaranteed quality.

2.5 MCS Dynamic Adjustment Algorithm

According to the radio transmission quality in the air, the system can dynamically adjust the Modulation and Coding Schemes (MCS -1, MCS-2, MCS-3, MCS -4, MCS-5, MCS-6, MCS-7, MCS-8 and MCS-9) to make full use of radio resources and increase the transmission rate on the condition of guaranteed quality.

2.6 PDCH Dynamic Conversion

The fixed PDCH and the dynamic PDCH are supported. The dynamic PDCHs can be converted between TCH and PDTCH according to the actual need. When the system is being initialized, it serves as TCH; when there is a need to provide packet services, it can be converted into PDCH, and when there is a demand for circuit services, it can be converted from PDCH to TCH.


7

2.7 Multiple Networking Modes

The Pb interface supports the star networking. One PCU can be connected with multiple BSCs.

The PCU equipment can be placed at the BSS side, or the SGSN side, or even the MSC side on some special occasions.

2.8 Supporting the MML Operation

M900/M1800 PCU supports the Man-Machine Language (MML) interface, and offers online information.

2.9 General OMC System for GSM/GPRS and Standard NM Interface

M900/M1800 PCU integrates Huawei OMC system, which supports both GSM and GPRS.

M900/M1800 PCU also supports SNMP.

2.10 Reliability Design

PCU takes the hardware protection measures like active/standby mode, load sharing and fault detection/separation to enhance system reliability. In terms of software, measures like timed tests, task monitoring, storage protection and resources check are taken for the sake of reliability.

2.11 Signaling Tracing on Both Um and Gb Interfaces

PCU system offers abundant signaling tracing functions for both the Um and the Gb interfaces, as well as detailed explanations of the signaling messages traced to facilitate fault locating and troubleshooting.

.


8

Chapter 3 System Architecture

3.1 Product Appearance

3.1.1 Cabinet Features

The standard 19-inch PCU cabinet is shown in Figure 3-1, with the dimensions (Length x Width x Height) listed below:

600mm (without side panels) × 795mm (without doors) × 1945mm (without top cover)

680mm (with two side panels) × 800mm (with doors) × 2100mm (with top cover)

Side panel dimensions: 2100mm×800mm×40mm

Height of the available space of the cabinet: 40U (1U=44.45mm).

800680

2100

Figure 3-1 Appearance of the PCU product cabinet


9

In compliance with the IEC297 Standards, the PCU cabinet features:

l Modular design which facilitates the installation, maintenance and capacity

expansion of the system.

l Light but strong structure thanks to the sheet metal used.

l Excellent electromagnetic shielding performance with the electromagnetic

compatibility fully considered.

l Feasible air duct design with desirable ventilation performance

l Plain yet nice appearance.

3.1.2 Cabinet Configuration

(1) Power Distribution Box (2) LAN switch frame (3) Dummy Panel (4) PCU Processing Frame (5) Cabinet

Figure 3-2 Typical configuration of the PCU cabinet

As shown in Figure 3-2, a typically configured PCU cabinet can fit in maximum 3 PCU processing frames.

3.2 Hardware Architecture

M900/M1800 PCU adopts distributed and highly modular hardware structure, high-speed backplane bus and high-performance CPUs, featuring easy transplantation, smooth expansion and powerful packet processing capability.

The PCU consists of two functional entities: POMU (PCU Operation & Maintenance Unit) and RPPU (Radio Packet Processing Unit). The logical structure of PCU is shown in Figure 3-3.


10

POMU

Signaling and data bus

RPPU

1+1LAN

BSC

Hard Disk

SGSN

RPPUN+1

POMU: PCU Operation & Maintenance Unit RPPU: Radio Packet Processing Unit (RPPU)

Figure 3-3 PCU logical structure

PCU mainly consists of the boards like POMU, HSC, RPPU, L2PU and PMC.

3.2.1 POMU

POMU board is in the PCU frame, responsible for operation, maintenance and configuration processing. It implements the interface protocols processing between the PCU and operators, and between PCU and OMC, as well as processing of services related to operation and maintenance.

The POMU boards are usually used in pairs. The active/standby boards supports warm backup. When the active board fails, the standby one will be switched to be active.

3.2.2 HSC

Each PCU frame is configured with 2 HSCs (Hot Swap Controllers).

Each PCU processing frame contains two 8-slot subsystems. HSC board is the bridge through which the POMU board can control the interface protocol processing boards of another sub-system. The POMU board of each 8-slot subsystem can control not only the interface protocol processing boards of the local subsystem, but also that of the other subsystem through the HSC of that subsystem (each POMU board has one corresponding HSC).

HSC board also controls the physical devices in the POMU frame, including the power-on of the interface protocol processing boards, peripherals, power supply, indicators, fan and alarm equipment.


11

3.2.3 RPPU

The RPPU board is the radio packet processing unit in the PCU processing frame. It performs functions such as the RLC/MAC protocols, the BSS part of the Gb interface protocol stack, Pb interface processing and G-Abis interface processing, etc.

Through the high-speed data bus, the RPPU communicates with other RPPUs, HSCs and POMUs in the PCU processing frame. Together they implement GPRS radio resource management. According to the software installed and L2PU plates mounted on them, RPPU board can be divided into two types: the RPPU for the Gb interface, and the RPPU for the Pb/G-Abis interface.

3.2.4 L2PU

L2PU (Layer 2 Protocol Processing Unit) is in the PCU processing frame. It is a small pinch plate mounted on the RPPU (for Pb or Gb). Each L2PU offers 4 standard external E1 interfaces.

3.2.5 PMC

PMC board is the Layer 2 protocol processing board in the PCU processing frame. It is a small pinch plate mounted on the RPPU board (for Gb). Each PMC offers 2 standard external E1 interfaces.

3.3 Software Architecture

M900/M1800 PCU system software is designed by strictly following software engineering requirements, and adopts the top-to-down and hierarchical modular programming method. Protocol software is designed by adopting the protocol engineering methods. Its development procedures include protocol description, inspection, implementation and testing phases. The Specification and Description Language (SDL) recommended by ITU-T is adopted to support the hierarchical, modular and structural software development. The strict and standard software development process makes it easy to understand and maintain the codes of the software, hence, ensuring a high software quality.

M900/M1800 PCU software refers to the programs running on processing boards in the PCU service module. Physically, PCU is a distributed system with each board running a different software system. Each of the board software comprises the platform software part and the GPRS special protocol software part.

M900/M1800 PCU software adopts the modular structure. Each function is enabled by a relatively independent module.

As shown in Figure 3-4, the software includes two parts, the platform software module and GPRS software module. The former is built up by the following functional parts: TCP/IP protocol processing module, operating system module, database management module, system maintenance module, alarm management module, equipment management module and system error tolerance module. The latter comprises Gb interface protocol processing, Um interface protocol processing and Pb interface processing module.


12

Alarm management

Equipment management

System maintenance

Pb interface processing

Um interface protocol processing

Gb interface protocol processing

Database management

System error tolerance

TCP/IP protocol processing

System software structure

Operating system

Platform software module

GPRS software module

Figure 3-4 PCU software system architecture


13

Chapter 4 Function and Application

4.1 Service Processing Function

4.1.1 Packet Channel Combinations Supported

l Combined PBCCH (PBCCH+ PCCCH+ PDTCH+ PACCH+ PTCCH)

l Combined PCCCH (PCCCH+ PDTCH+ PACCH+ PTCCH)

l Combined PDTCH (PDTCH+ PACCH+ PTCCH)

4.1.2 System Information Supported

l Basic PSI set, including PSI1, PSI2, PSI3 and PSI3bis.

l The broadcasting of packet service-related system information on BCCH,

Broadcasting of the GPRS service support indication in SI3, SI4, SI7 or SI8, and

broadcasting of GPRS service-related parameters in SI13.

l Broadcasting of the PSI on PBCCH, including PSI1, PSI2, PSI3, PSI3bis

broadcasting.

l Broadcasting of the PSI on PACCH.

l High-speed retransmitting of PSI.

4.1.3 MS Classes Supported

l MS of Class B

l MS of Class C

l MS with multi-TS capability of 1 to 12

4.1.4 MAC Modes Supported

The PCU supports dynamic allocation mode. This mode is a kind of multiplexing method for channel resources. In this mode, the network sends USF value over the downlink radio blocks to allocate the radio blocks on the corresponding uplink channel to the MS.

4.1.5 RLC Modes Supported

l RLC Acknowledged Mode

In this mode, the receiver will acknowledge the RLC data block, and the sender will retransmit the lost blocks to ensure the reliable transmission.


14

l RLC Unacknowledged Mode

In this mode, the receiver will not acknowledge the RLC data block, and the sender will not retransmit the lost one. The lost blocks will be sent by the receiver to the higher level for processing after interpolation.

4.1.6 Coding Schemes Supported

l CS-1 coding scheme, which offers the error correction function, with a data

transmission rate of 9.05kbit/s.

l CS-2 coding mode, which offers the error correction function less powerful than

the CS-1, with a data transmission rate of 13.4kbit/s.


the CS-1 and CS2, with a data transmission rate of 15.6kbit/s.


the CS-1, CS-2 and CS-3, with a data transmission rate of 21.4kbit/s.

l Dynamic change of the coding scheme, i.e. dynamical adjustment of PDCH

coding scheme according the RLC block retransmission rate of the

uplink/downlink TBF.

4.1.7 Network Control Modes Supported

The PCU supports the NC0. The MS performs autonomous cell selection without

sending the measurement report.

4.1.8 Network Operation Modes Supported

l Network Operation Mode I.

l Network Operation Mode II.

l Network Operation Mode III.

4.1.9 QoS Supported

The PCU supports the QoS of the Best Effort class, i.e. it will try its best to meet subscribers’ demand on QoS according to the radio resources condition at that time.

4.1.10 Accesses Supported

l Single-block access on CCCH.

l One-phase access on CCCH.

l Forced change from one-phase access request into two-phase access.

l Access on PACCH.

4.1.11 Assignments Supported

l Packet uplink resources assignment on PACCH.


15

l Packet downlink resources assignment on PACCH.

l Uplink immediate assignment for establishing TBF connection on CCCH.

l Downlink immediate assignment for establishing TBF connection on CCCH.

4.1.12 Pagings Supported

l Packet paging on CCCH.

l Circuit paging on CCCH.

l Paging in DRX mode.

l Packet paging of different identifications.

4.1.13 TA Update

l Supporting the continuous TA (Timing Advance) update procedure.

l Supporting the quick adjustment of TA initial value.

4.1.14 Measurement Report

The PCU supports the uplink measurement report.

The class and quality of the uplink transmission signals from mobile stations to BS will be worked out by BTS. Through the inband signaling of the TRAU frame on Abis interface, it will be transferred to the PCU to form a measurement report.

4.1.15 Power Control

The PCU supports the packet power control algorithm.

4.1.16 Traffic Controls Supported

l The uplink traffic control supports the rejection of immediate assignment on

CCCH.

l The downlink traffic control supports the downlink traffic control of both BVC and

MS.

4.1.17 Dynamic Conversion between TCH and PDCH.

l Supporting the conversion from TCH to PDCH during the establishment of TBF.

l Supporting the conversion from TCH to PDCH during the establishment of circuit

paging.

l Supporting the sharing of PDCH among the cells of the same RPPU.

4.1.18 PCCCH Access Function

l Supporting the short access on PACCH.

l Supporting the one-phase access on PCCCH.

l Supporting the two-phase access on PCCCH.


16

l Supporting the packet uplink resources assignment on PCCCH.

l Supporting the packet downlink resources assignment on PCCCH.

l Supporting the packet paging on PCCCH.

4.1.19 Modulation and Coding Schemes Supported

l MCS-1 coding scheme, which offers the data transmission rate of 8.8kbit/s.









l Dynamic change of the modulation and coding scheme, i.e. dynamical adjustment

of PDCH coding scheme according the BEP measurement report.

4.1.20 Link Quality Control Supported

l IR, incremental redundancy, enables higher data rates through combining

information from different transmissions of RLC data blocks when decoding.

l LA, link adaptation, changes the modulation and coding scheme according the link

quality.

4.1.21 Multiplexing of GPRS and EGPRS MSs

The GPRS and EGPRS Ms can be multiplexed dynamically on the same PDCH.


17

4.2 Networking

The PCU of the M900/M1800 GPRS BSS is a piece of semi-independent equipment. Functionally, it is a part of BSC, whereas in terms of location, it is relatively independent. It can be located either at the BSC site, or at the SGSN site, or even at the MSC site.

4.2.1 Networking Mode I

In this mode, PCU, placed at the BSS side, is directly connected with the BSC and SGSN via the E1 trunk cable. This is the common networking mode in practice.

There are two options for this networking mode. The first is that PCU is placed at the BSS side and directly connected with BSC. This mode is applied when PCU and BSC are in the same site or the BSCs in local network are close with each other. In the initial stage of GPRS deployment, BSC packet data which is of little traffic may be transited by PCU so as to reduce transmission cost by multiplexing the packet data of multiple BSCs to the E1 of Gb interface.

With the increase of traffic volume, PCU and BSC can be configured in pairs by adding transmission resources on Gb interface only. This networking mode as shown in Figure 4-1 can reduce transmission cost.

MSC/VLR

SGSN

PCU

BSS

BSS

A

Gb

HLR

Gs

Gr

GSM BSS GPRS CN

SS7

BSCBTS

BSCBTS

Figure 4-1 PCU networking mode 1 (PCU at the BSS side)

4.2.2 Networking Mode II

PCU is placed at the NSS side and is connected directly to BSC via Pb interface. PCU is also connected to SGSN directly, as shown in Figure 4-2.

This networking mode is applied when newly added equipment of GPRS in local network are close. In the case when BSC sites are scattered, close distribution of GPRS newly added equipment will facilitate the management. At the initial stage of GPRS, this networking mode is most applicable to scattered BSC sites. But with the development of the network, the first option is recommended.


18

MSC

SGSN

PCUBSS

BSS

HLR

Gr

GSM BSS GPRS CN

Gb

Gs

Pb

A

Pb

A

BTS BSC

BSCBTS

Gs

SS7

Figure 4-2 PCU networking mode 1 (PCU at the NSS side)

4.2.3 Networking Mode III

PCU is at the BSS side and connected to SGSN through frame relay network, as shown in Figure 4-3.

MSC

SGSN

PCU

BSS

BSS

A

Gb

HLR

Gr

GSM BSS GPRS CN

GbGs

SS7 FR

BSC

BSC

BTS

BTS

Figure 4-3 PCU Networking Mode III


19

Chapter 5 Operation and Maintenance

5.1 Overview

As a complex large system, PCU needs the support from an operation and maintenance sub-system to ensure the effective control.

The overall structure of the operation & maintenance sub-system can be divided into two parts: the agent at the PCU equipment side and the OMC at the user side. Being a part of the PCU software, the built-in operation & maintenance agent at the equipment side can monitor the real-time running condition of the system. It can issue control commands to PCU in accordance with the user’s input and report the control result. While the OMC at the user side feeds back the running condition of PCU to users on a friendly graphic interface.

The operation & maintenance sub-system has four functions, they are alarm management, performance measurement management, maintenance management and data configuration.

5.2 Alarm Management

PCU alarm management takes charge of collecting the system alarm messages. These alarm messages are stored in the hard disk of PCU equipment, and if OMC server is connected, sent to the OMC server for centralized storage. When the PCU system is abnormal or undergoing some maintenance operation, the system will send the message as an alarm to the user interface, notifying the maintenance personnel of the current status of the system and recommended solutions.

5.2.1 Features of Alarm Management

The PCU alarm system has the following features:

l Real time

Whenever there is a system alarm, the alarm management system will handle the alarm immediately and send it to the user interface.

l Hierarchical control In PCU system, all possible system alarms are classified into four levels according to their seriousness: critical, major, minor and warning. The more serious alarms will be given priority so that they can be solved in time.

l Convenient operation

The alarm message can be inquired through the OMC alarm console, or through the Telnet terminal connected to the PCU. For example, when the system generates a software fault alarm, the alarm information is available in the alarm terminal, including the frame No., board No. and software module where the alarm occurred. The alarm terminal also provides suggestions on handling the alarm.


20

5.2.2 Alarm Processing

After receiving an alarm message, PCU will first process it, then send it to the user interface. The alarm processing include the following procedures:

l When the alarm information is generated, the system will store the alarm data in

the hard disk for later inquiry.

l If the Telnet real-time alarm terminal is equipped, the alarm will be displayed at the

Telnet terminal.

l To ensure the safe transmission of alarm message to OMC, acknowledgement

and retransmission mechanism is adopted. The more serious alarm will be given

higher priority.

l If the PCU alarm box is installed, it will give audible and visible indications

corresponding to the level of the alarm.

5.3 Performance Measurement Management

The performance measurement function is mainly used to monitor traffic load and network performance. The measurement indices provide a solid foundation for judging the system performance. The performance measurement procedure is originated by OMC traffic statistics console (an application), and the collecting of measurement data is implemented by the traffic statistics module in PCU. The collected results are saved to the hard disk periodically.

5.3.1 Measurement Task Management

User’s measurement requirement is fulfilled by a series of arranged tasks. For measurement task, some basic information should be described, such as measurement start and end time, measurement period, and measurement type, etc. The system provides a group of basic operations for the users to interact with the system to implement their control over the tasks, including:

l Set up measurement task

Measurement task will be created based on the task element information input by users. A measurement task will not start until the system time reaches the very point that the user specified. A permanent task will not end unless it is deleted. If the user specify the end time, the task will terminate when the time is due.

l Delete measurement task

This is used to delete an established measurement task. The measurement result of the task will be deleted at the same time.

l Query task status

This is used to query whether the measurement task specified has been created.

l Query task measurement result

This is used to query the measurement result of an established task.


21

5.3.2 Measurement Result Management

Measurement task collects measurement results periodically according to the measurement period specified by the operator. The collected results are saved in the hard disk of the PCU system. The operator can conveniently view the measurement result of any specified time section via the OMC traffic statistics console.

5.4 Maintenance Management

Maintenance management operations on PCU system can be enabled through Telnet terminal connected to the PCU directly or via OMC.

In the Telnet terminal direct connection mode, the operator can send to the PCU operation and maintenance module the control commands that triggers PCU’s corresponding response, so as to achieve real-time control over the system. Upon receiving the operation command, the operation and maintenance module directly collects system status information and returns it to the terminal interface, or sends the control commands to other modules and returns the execution result to the Telnet terminal interface when the application modules have completed their processing.

Operations in OMC connection mode are originated by the OMC maintenance console, which interacts with the PCU via OAM service programs. Operation results are displayed on the maintenance console.

5.4.1 Overall Structure

In terms of software structure, operation and maintenance management mainly comprises the maintenance management module in PCU, OAM service program, OMC SHELL and OMC maintenance console, as shown in Figure 5-1.

For the maintenance operations originated via the maintenance console, first the maintenance console in OMC SHELL in correspondence to the involved PCU node shall be started to set up the connection between the maintenance console and the OAM agent server. The maintenance commands issued by the operator at the OMC maintenance console will be first sent to the OAM service program, which will forward the commands to the operation and maintenance module in the PCU. After command resolution processing, the operation result will be sent to the OMC maintenance console via the OAM service program.

OMCShell

Maintenanceconsole

Other consoles

AM

Maintenancemanagement

module

Appl. modulePCU OMC

TCP/IP

O

Figure 5-1 Structure of the maintenance management part


22

5.4.2 Main Features

l High efficiency and convenient operation

OMC operation terminal adopts graphic man-machine interfaces that makes leaning and operation easy.

l Remote/centralized maintenance

The unique OAM (OMC Agent Module) can fulfills remote/centralized maintenance.

l Client/Server structure

OAM integrates the functions of communication server and data server. Operations and maintenance tasks are all executed in the Client/Server mode. It supports simultaneous local/remote maintenance operations at multiple points.

5.5 Data Configuration

PCU operation parameters can be configured through man-machine language by way of command lines.

Following methods are provided to enter the command line interface:

l Via the TELNET client program.

l Select the desired PCU icon on the OMC SHELL graphic interface and then right

click to select the command terminal function.

As PCU data configuration is a huge task, the system also allows one time input of existing configurations after proper modification based on practical implementation.


23

Chapter 6 Reliability

6.1 System Protection Mechanism

l Software and hardware fault detection mechanism

During system operation, this mechanism detects in real-time the running status of software and hardware. Once a fault is detected, alarm will be generated, and corresponding measures will be taken to deal with the fault automatically.

l Redundancy configuration

POMU and HSC are configured in 1+1 redundancy, while RPPU is configured in N+1 redundancy.

l Overload, over-voltage and under-voltage protection

The power supply module of the system mainly includes AC power supply and DC power supply. Both are equipped with overload, over-voltage and under-voltage protection mechanism.

6.2 Error Tolerance

Both the POMU and HS C boards will switch their active/standby boards in case of active board failure.

When failure occurs to the RPPU, the cell configured to the failed board will be migrated to the standby board to continue the services.

The information concerning the software failure on boards will be automatically recorded in the NvRAM on POMU board. It can be browsed using maintenance commands.

6.3 MTBF and MTTR

MTBF (Mean Time Between Failures): 31497 hours

MTTR (Mean Time To Repair): 0.25 hours

Availability: 99.9992%

Average system down time per year: 0.14 hours

6.4 Data Security

The PCU provides program protection measures.

l Monitoring the running status of system task.

The system will monitor the time that every task occupies CPU during its running process. Once a task occupies the CPU for too long time, system will take proper measures and generate CPU alarm.


24

l Protection of abnormal task field.

In the case of software abnormality, the system can permanently store the field information for the purpose of browsing and fault locating. The board can reset at the same time.

6.5 Operation Security

The operation interfaces provided to users include TELNET interface and OMC graphic interface.

For TELNET maintenance interface, four levels of operation and management authorities are provided, i.e. common user, basic maintenance user, advance maintenance user and supervisor. Each user is allocated with a user name and a password and O&M authority level by system administrator (for TELNET maintenance interface, the system administrator is named as "supervisor").

Operations which have great effect on the system (such as reset, writing configuration data to Flash Memory, etc.) requires user confirmation, so as to prevent mis-operations.

For the operation of OMC graphic interface, each user is provided with a password, which is allocated by system administrator.


25

Chapter 7 Technical Indices

7.1 Processing Capability

The processing capability of the PCU is measured by the number of the activated PDCHs that can be processed by the Um interface and the throughput of the Gb interface. The processing capability of the PCU with the maximum configuration is given in Table 7-1.

Table 7-1 The processing capability of PCU with the maximum configuration

Number of activated PDCHs Number of E1s of Pb interface

Gb interface throughput

Number of E1s on Gb interface

1080(GPRS) or 900(EGPRS) 72 24Mbit/s 12

The processing capability of the PCU with the minimum configuration is given in Table 7-2.

Table 7-2 The processing capability of PCU with the minimum configuration

Number of activated PDCHs

Number of E1s of Pb interface

Gb interface throughput

Number of E1s on Gb interface

120(GPRS) or 100(EGPRS) 8 8Mbit/s 4

7.2 Overall Technical Indices

The overall technical indices of PCU system are listed in Table 7-3.

Table 7-3 PCU Overall Technical Indices

Index Value

E1 port (Pb interface) 72 Maximum number of ports supported. E1 port (Gb interface) 12 MTBF (Mean Time Between Failures) ú31497 h Reliability MTBF (Mean Time To Repair) ñ15min


26

7.3 Structural Indices

The structural indices of PCU system are listed in Table 7-4.

Table 7-4 Structural indices

Index Value

Cabinet standard IEC297 standard and IEEE standard Cabinet dimensions 2100mm%600mm%800mm (height % width % depth) Height of the available space of the cabinet 40U*

Cabinet weight ñ290kg Floor bearing capacity of the equipment room ú450 kg/m2

l Note: 1U=44.45 mm

7.4 Electric Indices

The electric indices of PCU system are listed in Table 7-5.

Table 7-5 PCU electric indices

Index Value

PCU processing frame (single frame in full configuration) ñ1200W

Power distribution box ñ20W Power consumption

LAN Switch ñ50W Power supply -48 DC power supply, working power input range: –40v to –57v EMC In compliance with the requirements of the ETSI EN300 386 V1.2.1(2000-03)

7.5 System Operation Environment

The system operation environment requirements of PCU are listed in Table 7-6.

Table 7-6 Requirement on system operation environment

Index Value

Temperature 0? ~ +45? Humidity 10% ~ 90%

Air pressure 70kPa ~ 106kPa Wind speed <5.0 m/s Solar radiation <700 W/m2 Heat radiation <600 W/m2

Earthquake standard In compliance with the requirements of the EUROPEAN ETS 300 019-1-3


27

7.6 Other Indices

The noise and safety indices of PCU system are listed in Table 7-7.

Table 7-7 Noise and safety indices

Index Value

Noise <72dB, which is in compliance with the requirements of the EUROPEAN ETS 300 753

Safety In compliance with the requirements of UL 60950, EN60950, IEC60825, and GB4943-2000


28

Appendix A Technical Specifications and

Standards

PCU is in compliance with the following ETSI specifications.

ETSI specifications Description

GSM 02.60 General Packet Radio Service (GPRS); Service description; Stage 1 GSM 03.60 Stage 2 Service Description of the General Packet Radio Service GSM 03.03 Numbering, addressing and identification GSM 03.07 Restoration procedures GSM 03.22 Functions related to Mobile Station (MS) in idle mode and group receive mode GSM 03.64 Overall description of the General Packet Radio Service (GPRS) Radio interface GSM 04.07 Mobile radio interface signaling layer 3; General aspects GSM 04.08 Mobile radio interface layer 3 specification

GSM 04.60 General Packet Radio Service (GPRS); Mobile Station (MS) – Base Station System (BSS) interface; Radio Link Control / Medium Access Control (RLC/MAC) protocol

GSM 04.64 Mobile Station – Serving GPRS Support Node (MS – SGSN) Logical Link Control (LLC) layer specification

GSM 04.65 Mobile Station (MS) – Serving GPRS Support Node (SGSN); Subnetwork Dependent Convergence Protocol (SNDCP)

GSM 05.01 Physical layer on the radio path, General description GSM 05.02 Multiplexing and multiple access on the radio path GSM 05.03 Channel coding GSM 05.04 Modulation GSM 05.05 Radio transmission and reception GSM 05.08 Radio subsystem link control GSM 05.10 Radio subsystem synchronization

GSM 08.08 Mobile Switching Center – Base Station System (MSC – BSS) interface: Layer 3 specification

GSM 08.14 Base Station System (BSS) – Serving GPRS Support Node (SGSN) interface; Gb interface layer 1

GSM 08.16 Base Station System (BSS) – Serving GPRS Support Node (SGSN) interface; Network Service

GSM 08.18 Base Station System (BSS) – Serving GPRS Support Node (SGSN); BSS GPRS Protocol (BSSGP)

PCU is in compliance with the following ITU-T recommendations.

ITU-T recommendations Description

ITU -T Q.921 ISDN user-network interface – Data link layer specification ITU -T Q.922 ISDN data link lay er specification for frame mode bearer services ITU -T Q.931 ISDN user-network interface layer 3 specification for basic call control

ITU -T Q.933 Signaling specifications for frame mode switched and permanent virtual connection control and status monitoring


29

Appendix B Abbreviations

A AB Access Burst AC Access Class (C0 to C15) ACC Automatic Congestion Control ACCH Associated Control Channel ACK ACKnowledgement AGCH Access Grant Channel ASN.1 Abstract Syntax Notation One ARFCN Absolute Radio Frequency Channel Number ARQ Automatic ReQuest for retransmission B BA BCCH Allocation BCC Base Transceiver Station (BTS) Color Code BCCH Broadcast Control Channel BCD Binary Coded Decimal BER Bit Error Rate BFI Bad Frame Indication BN Bit Number BSC Base Station Controller BSIC Base transceiver Station Identity Code BSIC -NCELL BSIC of an adjacent cell BSS Base Station System BSSAP Base Station System Application Part BSSGP Base Station System GPRS Protocol BSSMAP Base Station System Management Application Part BSSOMAP Base Station System Operation and Maintenance Application Part BTS Base Transceiver Station C CA Cell Allocation CC Call Control CCCH Common Control Channel CCH Control Channel CCU Channel Codec Unit CI Cell Identity CIR Carrier to Interference Ratio CKSN Ciphering Key Sequence Number CM Connection Management CMD CoMmanD COM COMplete C/R Command/Response field bit CRC Cyclic Redundancy Check (3 bit) D DB Dummy Burst DCCH Dedicated Control Channel DCS-1800 Digital Cellular System at 1800MHz DL Data Link (layer) DLCI Data Link Connection Identifier DRX Discontinuous reception (mechanism) DTAP Direct Transfer Application Part DTE Data Terminal Equipment DTX Discontinuous transmission (mechanism) E EA External Alarms EGPRS Enhanced GPRS EIR Equipment Identity Register EMC ElectroMagnetic Compatibility EMMI Electrical Man Machine Interface


30

EPROM Erasable Programmable Read Only Memory ERR ERRor ETR ETSI Technical Report ETS European Telecommunication Standard ETSI European Telecommunications Standards Institute F FACCH Fast Associated Control Channel FB Frequency correction Burst FCCH Frequency Correction Channel FCS Frame Check Sequence FH Frequency Hopping FN Frame Number G GMSC Gateway Mobile-services Switching Center GMSK Gaussian Minimum Shift Keying (modulation) GPRS General Packet Radio Service GSM Global System for Mobile communications GSM PLMN GSM Public Land Mobile Network H HDLC High level Data Link Control HLR Home Location Register HPLMN Home PLMN HSC Hot Swappable Control HSN Hopping Sequence Number I I Information frame ID Identification/Identity/Identifier IE (signaling) Information Element IEI Information Element Identifier IMEI International Mobile station Equipment Identity IMSI International Mobile Subscriber Identity ISDN Integrated Services Digital Network ISO International Organization for Standardization ITU International Telecommunication Union IWF InterWorking Function K Kc Ciphering key Ki Individual subscriber authentication key L L1 Layer 1 L2PU Layer 2 Process Unit L2R Layer 2 Relay L3 Layer 3 LA Location Area LAC Location Area Code LAI Location Area Identity LAPDm Link Access Protocol on the Dm channel LCS Location Service LLC Logical Link Control (layer) LLC-PDU Logical Link Control Packet Data Unit LPLMN Local PLMN LU Location Update M M Mandatory MA Mobile Allocation MAC Medium Access Control MAI Mobile Allocation Index MAIO Mobile Allocation Index Offset MCC Mobile Country Code MCS Modulation and Coding Scheme ME Mobile Equipment MM Mobility Management MMI Man Machine Interface MNC Mobile Network Code


31

MO Mobile Originated MoU Memorandum of Understanding MS Mobile Station MSC Mobile-services Switching Center, Mobile Switching Center MSCM Mobile Station Class Mark MSISDN Mobile Station International ISDN Number MT Mobile Terminated N NB Normal Burst NCC Network (PLMN) Color Code NCELL Neighboring (of current serving) Cell NM Network Management NSAP Netw ork Service Access Point NT Non Transparent O O Optional OAM Operation Administration Maintenance O&M Operations & Maintenance OMC Operations & Maintenance Center OML Operations and Maintenance Link OS Operating System OSI Open System Interconnec tion OSI RM OSI Reference Model P PACCH Packet Associated Control CHannel PAGCH Packet Access Grant CHannel PBCCH Packet Broadcast Control CHannel PCCCH Packet Common Control CHannel PCH Paging CHannel PCM Pulse Code Modulation PCU Packet Control Unit PD Protocol Discriminator PDCH Packet Data CHannel PH PHysical (layer) PICS Protocol Implementation Conformance Statement PIN Personal Identification Number PLMN Public Lands Mobile Network POMU Packet Operation & Maintenance Unit PP Point-to-Point PPCH Packet Paging CHannel PRACH Packet Random Access CHannel PSI Packet System Information PSTN Public Switched Telephone Network Q QoS Quality of Service R RA RAndom mode request information field RACH Random Access CHannel REJ REJect(ion) REL RELease REQ REQuest RF Radio Frequency RFCH Radio Frequency CHannel RFN Reduced TDMA Frame Number RFU Reserved for Future Use RLC Radio Link Control RPPU Radio Packet Process Unit RRBP Relative Reserved Block Period RSL Radio Signaling Link RXLEV Received signal level RXQUAL Received Signal Quality S SW SoftWare SABM Set Asynchronous Balanced Mode


32

SACCH Slow Associated Control CHannel SAP Service Access Point SAPI Service Access Point Indicator SB Synchronization Burst SCH Synchronization CHannel SDCCH Stand-alone Dedicated Control CHannel SDU Service Digital Unit SGSN Service GPRS Support Node SI13 System Information 13 SIM Subscriber Identity Module SMG Special Mobile Group SMS Short Message Service SMSCB Short Message Service Cell Broadcast SMS-SC Short Message Service - Service Center SMS/PP Short Message Service/Point-to-Point SS Supplementary Service SS System Simulator SS7 Signaling System No. 7 T TA Terminal Adapter TA Timing Advance (between an MS and its serving BTS) TAF Terminal Adaptation Function TBF Temporary Block Flow TCH Traffic CHannel TCP Transmission Control Protocol TDMA Time Division Multiple Access TE Terminal Equipment Tei Terminal endpoint identifier TFI Temporary Flow Identity TI Transaction Identifier TLLI Temporary Logical Link Identity TMN Telecommunications Management Network TMSI Temporary Mobile Subscriber Identity TN Timeslot Number TOA Time of Arrival TRX Transceiver TS Time Slot TS Technical Specification TSC Training Sequence Code U UPD Up to date USF Uplink State Flag V VLR Visitor Location Register VMSC Visited MSC VPLMN Visited PLMN

Documents

PCU V300R005 System Description