Satellite Transmission

Satellite Transmission Feature Parameter Description

Copyright Huawei Technologies Co., Ltd. 2010. All rights reserved.

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Huawei Proprietary and Confidential Copyright Huawei Technologies Co., Ltd

BSS Satellite Transmission Contents

Issue 01 (2010-01-20) Huawei Proprietary and Confidential Copyright Huawei Technologies Co., Ltd

iii

Contents 1 Introduction ................................................................................................................................1-1

1.1 Scope ............................................................................................................................................ 1-1 1.2 Intended Audience ........................................................................................................................ 1-1 1.3 Change History.............................................................................................................................. 1-1

2 Overview of Call Control .........................................................................................................2-1

3 Call Classification......................................................................Error! Bookmark not defined. 3.1 MOT ................................................................................................. Error! Bookmark not defined. 3.2 MTC............................................................................................................................................... 3-1 3.3 Emergency Call ................................................................................ Error! Bookmark not defined.

4 Call Release.................................................................................Error! Bookmark not defined. 4.1 Overview .......................................................................................... Error! Bookmark not defined. 4.2 MS-Initiated Call Release................................................................. Error! Bookmark not defined. 4.3 Network-Initiated Call Release......................................................... Error! Bookmark not defined.

5 Parameters ..................................................................................Error! Bookmark not defined.

6 Counters......................................................................................................................................5-1

7 Glossary .......................................................................................Error! Bookmark not defined.

8 Reference Documents .............................................................................................................7-1

BSS Satellite Transmission 1 Introduction


1-1

1 Introduction 1.1 Scope This document introduces the Satellite Transmission feature of Huawei GSM Base Station Subsystem (BSS) and describes the function and principle of satellite transmission, including satellite transmission over A, Abis, Ater, Pb, and Gb interfaces.

1.2 Intended Audience This document is intended for:

z Personnel who need to understand Satellite Transmission z Personnel who work with Huawei products

1.3 Change History This section provides information on the changes in different document versions.

There are two types of changes, which are defined as follows:

z Feature change: refers to the change in the Satellite Transmission feature of a specific product version.

z Editorial change: refers to the change in wording or the addition of the information that was not described in the earlier version.

Document Issues The document issues are as follows:

z 01 (2010-01-20)

01 (2010-01-20) This is the initial issue.of GBSS9.0.

BSS Satellite Transmission 2 Overview of Satellite Transmission


2-1

2 Overview of Satellite Transmission Satellite transmission uses a satellite for telecommunications and is very useful in remote mountain areas or sparsely populated plains.MOC.

Aiming at characteristics of satellite transmission, Huawei BSS solves the problems such as delay, jitter, and bit error in satellite transmission through the optimization of signaling procedures and the adjustment of relevant timers.

The delay in satellite transmission may worsen the performance counters such as call drop rate, handover success rate, and assignment success rate.

Huawei BSS supports simultaneous satellite transmission over multiple interfaces, including

z Satellite transmission over A interface z Satellite transmission over Ater interface z Satellite transmission over Abis interface z Satellite transmission over Pb interface z Satellite transmission over Gb interface

BSS Satellite Transmission 3 Technical Description


3-1

3 Technical Description 3.1 Network Topologies of Satellite Transmission Huawei BSS supports satellite transmission over multiple interfaces. Satellite transmission over Abis interface is widely used.

The networking of satellite transmission over Abis interface often uses star topology. Figure 3-1shows a typical networking of satellite transmission.

The principle of satellite transmission over Abis, Ater, Pb, and Gb interfaces is the same as that over Abis interface.

Figure 3-1 Typical networking of satellite transmission

The satellite communication is composed of a communications satellite and earth stations. MTC procedure

The communications satellite is usually a geosynchronous satellite, which orbits the equator. The satellite orbits in the same direction as that of the earth rotation. It takes the same time for the satellite to orbit the earth for one circle and the earth to rotate on its own axis for one circle. The satellite is composed of the control system, communication system (antennas and repeaters), telemeter system, power supply system, and temperature control system.

The earth station is composed of the antenna system, transceiver, channel terminal (modem), communication control system, and power supply system.

z The earth station generally used for satellite transmission is a large international or European standard communication station, which features high data rate, large aperture, and high cost. User data converges on the earth station through the terrestrial communication network for communication with the satellite.

z The Very Small Aperture Terminal (VSAT) is an earth station that constitutes a private network. In the VSAT, subscribers under different BTSs use their separate earth stations for communication. The VSAT features lower cost, smaller aperture, and more flexible deployment.

3 Technical Description BSS

Satellite Transmission

3-2 Huawei Proprietary and Confidential Copyright Huawei Technologies Co., Ltd

Issue 01 (2010-01-20)

3.2 Satellite Transmission over Abis Interface Satellite transmission mainly differs from common terrestrial transmission in the delay problem. Radio wave travels at the speed of light and the satellite is about 80,000 km away from the earth. The unidirectional transmission delay in satellite transmission thus is about 270 ms and the round-trip delay is about 540 ms.

Satellite transmission may cause problems such as delay, jitter, and bit error, so common GSM equipment does not support satellite transmission. Based on the characteristics of satellite transmission, the BSC6900 adjusts accordingly by sending configuration requirements to the LAPD and the BTS. By sending transmission mode to the BTS, the BSC6900 enables the BTS to internally differentiate transmission mode and implement control at the link level. The details are as follows:

z Processing of the LAPD

During the processing of the LAPD, the timer length is prolonged and the value of the sliding window is increased to eliminate the impact of transmission delay. When satellite transmission is chosen, the sliding window automatically updates its value to the corresponding value of satellite transmission and users can modify the value as practically required.

z TRAU frame adjustment

The adjustment algorithm of TRAU frames is changed from adjustment at a fixed period to adaptive adjustment.

z Operating mode of the BTS clock

To work with satellite transmission, the BSC supports the internal clock of the BTS in compliance with GSM protocol requirements of clock precision.

z BTS supporting satellite transmission

Huawei BTS supports satellite transmission and automatically updates data on the link layer according to the transmission mode requirement sent from the BSC.

3.3 Satellite transmission over A interface On the BSC6900, the transmission mode of the MTP3 link over A interface supports satellite transmission. When satellite transmission over A interface is used, data on the control panel over A interface updates automatically to eliminate the impact of long delay in satellite transmission.

3.4 Satellite transmission over Ater interface On the BSC6900, the transmission mode of the signaling link over Ater interface supports satellite transmission. When satellite transmission over Ater interface is used, the timer length of the signaling link over Ater interface automatically prolongs and the value of the sliding window can be modified as practically required to adapt to the delay in satellite transmission.

3.5 Satellite transmission over Pb interface The link layer on the Pb interface adopts the Link Access Procedure-D channel (LAPD) protocol. The processing of the LAPD over the Pb interface is the same as that over the Abis interface.

BSS Satellite Transmission 4 Parameters


4-1

4 Parameters This chapter describes the parameters related to satellite transmission.

For the description of each parameter, see Table 4-1. For the default value, value ranges, and MML commands of each parameter, see Table 4-2.

Table 4-1 Parameter description (1)

Parameter Description

Transmission Mode The Ater signaling link operates in the terrestrial transmission or satellite transmission mode. In the areas such as desert and lake where the terrestrial transmission is difficult, the satellite transmission can be used.

Satellite flag Satellite flag

Clock Mode Clock mode

RSL LAPD Window Size Size of the RSL LAPD window

SDCCH Dynamic Allocation Allowed

Whether to allow SDCCH dynamic allocation, that is, whether to allow dynamic conversion between TCHs and SDCCHs.

T200 SDCCH This parameter specifies the timeout value of timer T200 used for the SDCCH over the Um interface. T200 prevents the data link layer from deadlock during data transmission. The data link layer transforms the physical link that is vulnerable to errors into a sequential non-error data link. The entities at the two ends of this data link use the acknowledgement retransmission mechanism. Each message must be confirmed by the peer end. In unknown cases, both ends are waiting if a message is lost. At this time, the deadlock of the system occurs. Therefore, the transmit end must establish a timer. When the timer expires, the transmit end regards that the receive end does not receive the message and then the transmit end retransmits the message. The number of retransmissions is determined by N200. T200 and the N200 ensure that the data link layer sequentially transmits data and that the transmission is free from errors.

T200 SACCH SDCCH This parameter specifies the expiry value of timer T200 used for the SACCH on the SDCCH. For the function of timer T200 and the effect of the parameter, see the description of "T200 SDCCH".

4 Parameters BSS



Issue 01 (2010-01-20)


T200 SDCCH SAPI3 This parameter specifies the expiry value of timer T200 when the SDCCH supports SAPI3 services. For the function of timer T200 and the effect of the parameter, see the description of "T200 SDCCH".

MS MAX Retrans Maximum number of Channel Request messages that can be sent by an MS in an immediate assignment procedure. After the MS initiates the immediate assignment procedure, it always listens to the messages on the BCCH and all the common control channels (CCCHs) in the CCCH group to which the MS belongs. If the MS does not receive Immediate Assignment or Immediate Assignment Extend messages, it retransmits Channel Request messages at a specified interval. If the downlink quality is poor, the MS may send SABM frames to the BTS multiple times.

T3168 T3168 is used to set the maximum duration for the MS to wait for the uplink assignment message. After the MS originates the uplink TBF setup request by sending the packet resource request or the channel request in the packet uplink acknowledge message, the timer T3168 is started to wait for the packet uplink assignment message on the network side. If the MS receives the packet uplink assignment message before T3168 expires, T3168 is reset. Otherwise, the MS originates the packet access request for four times. Then the MS regards this as the TBF setup failure.

T3192 Duration of releasing the TBF after the MS receives the last data block. When the MS receives the RLC data block containing the flag identifying the last data block and confirms that all the RLC data blocks in the TBF are received, the MS sends the packet downlink acknowledge message containing the last flag acknowledgement and the timer T3192 is started. If the timer T3192 expires, the MS releases the TBF related resources and starts monitoring the paging channel. During TBF releasing, if the MS is the half duplex mode and receives the packet uplink assignment, the MS responds this command. During TBF releasing, if the MS is the half duplex mode and receives no packet uplink assignment message, the MS enters the packet idle mode. If the MS is in the dual transmission mode, the MS enters the special mode.



4-3


BS_CV_MAX This parameter is used to set the parameter BS_CV_MAX for MS countdown. This parameter is used for the MS to calculate the CV. This parameter also determines the duration of the timer T3198. When the MS sends one uplink RLC data block, the receiving state of this data block is set to Pending and the timer T3198 is started. If the MS receives the packet uplink acknowledge before the timer T3198 expires, the MS updates the receiving state of each uplink RLC data block according to the bit map in the message. If the timer T3198 of the RLC data block in the Pending state expires, the MS sets the receiving state of this data block to Nack and retransmits the data bloc.

Table 4-2 Parameter description (2)

Parameter

Default Value

GUI Value Range

Actual Value Range

Unit MML Command

Impact

Transmission Mode

TRRS TRRS(Terrestrial Transmission), SATEL(Satellite Transmission)

TRRS, SATEL

None ADD ATERSL(Optional)

ATERCONSL

Satellite flag

NO NO(NO),YES(YES)

NO,YES

None ADD MTP3LNK(Optional)

MTP3 Link

4 Parameters BSS



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Paramet Default GUI Value Actual Unit MML Impact er Value Range Value Command

Range

Clock Mode

None INCLK(Internal Clock), BSCCLK(Trace BSC Clock), EXCLK(External Synchro Clock), IPCLK(IP Clock), TRANSCLK(Trace Trans Clock), GPSCLK(Trace GPS Clock), UMCLK(Um Clock), PEERCLK(PEER Clock)

INCLK, BSCCLK, EXCLK, IPCLK, TRANSCLK, GPSCLK, UMCLK, PEERCLK

None SET BTSCLKPARA(Mandatory)

None

RSL LAPD Window Size

4 0~96 0~96 None SET BTSLAPDWS(Optional)

BTS

SDCCH Dynamic Allocation Allowed

YES NO(No), YES(Yes)

NO, YES

None SET GCELLBASICPARA(Optional)

Cell

T200 SDCCH

60 1~255 5~1275, step: 5

ms SET GCELLCCTMR(Optional)

Cell

T200 SACCH SDCCH

60 1~255 10~2550, step: 10


Cell

T200 SDCCH SAPI3

60 1~255 5~1275, step: 5


Cell



4-5

Paramet Default GUI Value Actual Unit MML Impact er Value Range Value Command

Range

MS MAX Retrans

4_Times 1_Times(1_Times), 2_Times(2_Times), 4_Times(4_Times), 7_Times(7_Times)

1_Times, 2_Times, 4_Times, 7_Times

None SET GCELLCCBASIC(Optional)

Cell

T3168 500ms 500ms(500ms), 1000ms(1000ms), 1500ms(1500ms), 2000ms(2000ms), 2500ms(2500ms), 3000ms(3000ms), 3500ms(3500ms), 4000ms(4000ms)

500ms, 1000ms, 1500ms, 2000ms, 2500ms, 3000ms, 3500ms, 4000ms

ms SET GCELLPSBASE(Optional)

Cell

T3192 500ms 0ms(0ms), 80ms(80ms), 120ms(120ms), 160ms(160ms), 200ms(200ms), 500ms(500ms), 1000ms(1000ms), 1500ms(1500ms)

0ms, 80ms, 120ms, 160ms, 200ms, 500ms, 1000ms, 1500ms

ms SET GCELLPSBASE(Optional)

Cell

BS_CV_MAX

10 015 015 None SET GCELLPSBASE(Optional)

Cell

BSS Satellite Transmission 5 Counters


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5 Counters For the counters, see the BSC6900 GSM Performance Counter Reference.

BSS Satellite Transmission 6 Glossary


6-1

6 Glossary For the acronyms, abbreviations, terms, and definitions, see the Glossary.

BSS Satellite Transmission 7 Reference Documents


7-1

7 Reference Documents z BSC6900 Feature List z BSC6900 Basic Feature Description z GBSS Reconfiguration Guide z BSC6900 GSM Parameter Reference z BSC6900 GSM MML Command Reference

1 Introduction 1.1 Scope 1.2 Intended Audience 1.3 Change History 2 Overview of Satellite Transmission 3 Technical Description 3.1 Network Topologies of Satellite Transmission 3.2 Satellite Transmission over Abis Interface 3.3 Satellite transmission over A interface 3.4 Satellite transmission over Ater interface 3.5 Satellite transmission over Pb interface

4 Parameters 5 Counters 6 Glossary 7 Reference Documents