01-20 EGPRS

20 EGPRS

About This Chapter

20.1 OverviewThis topic describes the EGPRS. The Enhanced Data Rate for GSM Evolution (EDGE) canprovide high-rate data services.

20.2 AvailabilityThis topic describes the availability of EGPRS. The realization of EDGE depends on thecooperation of relevant NEs, software, and licenses.

20.3 ImpactThis topic describes the impact of EGPRS. The impact of EGPRS mainly refers to the impacton system performance.

20.4 Technical DescriptionThis topic describes the technical description of EGPRS. EDGE is a phase of evolving into thePS service. EDGE can be called as 2.75 G mobile communication technology. If the equipmenton the current network remains unchanged, the relevant software needs to be upgraded. Therealization of EDGE can enhance the transmission rate of the packet data.

20.5 CapabilitiesThis topic describes the capabilities of EDGE.

20.6 ImplementationThe EDGE implementation consists of configuring EDGE and disabling EDGE.

20.7 Maintenance InformationThis topic describes the maintenance information on EDGE. The maintenance information onEDGE consists of information on alarms and on performance counters.

20.8 References

HUAWEI BSC6000 Base Station SubsystemBSS Feature Description 20 EGPRS

Issue 01 (2007-09-05) Huawei Technologies Proprietary 20-1

20.1 OverviewThis topic describes the EGPRS. The Enhanced Data Rate for GSM Evolution (EDGE) canprovide high-rate data services.

Definition

EDGE consists of the Enhanced GPRS (EGPRS) and the Enhanced Circuit Switched Data(ECSD).

l EGPRS is the enhanced GPRS. The 8PSK modulation mode is added to EGPRS so that therate of a single channel is improved. The maximum rate of a single channel is 59.2 kbit/s.

l ECSD is the enhanced High Speed Circuit Switched Data (HSCSD).

NOTE

Huawei BSS supports only EGPRS. Unless specified, EDGE indicates EGPRS.

Purposes

EDGE improves the rate of the data services in GSM. EDGE quadruples the rate of the Uminterface through the new modulation mode and the new coding mode.

Terms

None

Abbreviation

Abbreviation Full Spelling

EDGE Enhanced Data Rate for GSM Evolution

GPRS General Packet Radio Service

PCIC Packet Circuit Identity Code

BER Bits Error Rate

BVC BSSGP Virtual Connection

BSSGP Base Station System GPRS Protocol

QoS Quality of Service

TBF Temporary Block Flow

CCCH Common Control Channel

PCCCH Packet Common Control Channel

PACCH Packet Associated Control Channel

RLC Radio Link Control

20 EGPRSHUAWEI BSC6000 Base Station Subsystem

BSS Feature Description

20-2 Huawei Technologies Proprietary Issue 01 (2007-09-05)

20.2 AvailabilityThis topic describes the availability of EGPRS. The realization of EDGE depends on thecooperation of relevant NEs, software, and licenses.

Network Elements InvolvedTable 20-1 lists the network elements involved in EDGE.

Table 20-1 Network Elements Involved

MS BTS BSC PCU SGSN GGSN MSC HLR

√ √ √ √ √ √ - √

NOTE

l -: not involved

l √: involved

Software ReleasesTable 20-2 lists the versions of GBSS products that support EDGE.

Table 20-2 GBSS products and related versions

Product Version

BSC BSC6000 V900R001C01 and laterreleases

BTS BTS3X G3BTS32V302R002C05SP01and later releases

BTS3012A All releases

BTS3001C All releases



BTS3012 All releases

BTS3012AE All releases

MiscellaneousEDGE can be configured only when GPRS is configured. If GPRS is not configured, the BSCconfigures GPRS automatically when configuring EDGE.



20.3 ImpactThis topic describes the impact of EGPRS. The impact of EGPRS mainly refers to the impacton system performance.

Impact on System Performancel The enabling of EDGE decreases the maximum number of TRXs supported by one E1

cable in different topologies. Thus, the number of TRXs that each GMPS or GEPS supportsdecreases. The number of idle timeslots and TRXs that each E1 cable can be configuredwith must meet the following requirement: the number of the configured TRXs + (thenumber of the configured idle timeslots/8) ≤ the maximum number of the configured TRXs

l The enabling of EDGE decreases the capacity of the RPPUs in the PCU. The number ofthe activated PDCHs by each RPPU decreases from 120 to 100.

Impact on Other FeaturesNone

20.4 Technical DescriptionThis topic describes the technical description of EGPRS. EDGE is a phase of evolving into thePS service. EDGE can be called as 2.75 G mobile communication technology. If the equipmenton the current network remains unchanged, the relevant software needs to be upgraded. Therealization of EDGE can enhance the transmission rate of the packet data.

20.4.1 8PSK Modulation ModeThis topic describes the 8PSK modulation mode. In 8PSK modulation mode, symbols areindicated by the absolute phases of signals.

20.4.2 EGPRS Transmit PowerThis topic describes the transmit power used in EDGE in 8PSK modulation mode.

20.4.3 MCS-1 to MCS-9 Coding SchemesThis topic describes MCS-1 to MCS-9 coding schemes. EDGE uses MCS-1 to MCS-9 codingschemes.

20.4.4 Link Quality ControlThis topic describes the link quality control. The link quality control is the method of enablingthe system to adapt to the radio transmission environment dynamically in data transmissionthrough the change in modulation modes and coding modes so that the link quality can beimproved.

20.4.5 Dynamic Addition of SubtimeslotsThis topic describes the dynamic addition of subtimeslots. The dynamic addition of subtimeslotsis a process in which several timeslots on the Abis interface are mapped to one traffic channel.Then, they are divided and combined on both the TX and the RX ends.

20.4.1 8PSK Modulation ModeThis topic describes the 8PSK modulation mode. In 8PSK modulation mode, symbols areindicated by the absolute phases of signals.




The GSM system uses the Gaussian minimum shift keying (GMSK) modulation mode. In GMSKmodulation mode, bit 0 or 1 is indicated by the change in signal phases. Each phase change mapswith a symbol.

In 8PSK modulation mode, symbols are indicated by the absolute phases of signals. There areeight possible symbols and each symbol maps with three bits. Therefore, the data rate in EDGEcan theoretically be three times the data rate in GSM. Figure 20-1 shows the I/Q relations forthe modulation and demodulation in EDGE.

Figure 20-1 I/Q relations for the modulation and demodulation in EDGE

GPRS:GMSK Modulation

GPRS:8PSK Modulation

1

0

Q

I

Q

I

(0,1,0)

(0,0,0)

(0,0,0)

(1,0,1)

(1,0,0)

(1,1,0)

(1,1,1)

(0,1,1)

NOTE

In terms of performance, the 8PSK modulation mode is better than the GMSK modulation mode. Thedemodulation threshold of the 8PSK mode, however, is higher than the demodulation threshold of theGMSK mode. The modulation mode is radio environment specific. The PCU automatically adjusts themodulation mode based on the BER report received from an MS. Therefore, the modulation anddemodulation mode that EDGE uses can be 8PSK or GMSK.

Table 20-3 describes the mapping between modulation bits and symbol parameters 1 that areshown in Figure 20-1.

Table 20-3 Mapping between modulation bits and symbol parameters 1

Modulation Bit Symbol Parameter 1

(1,1,1) 0

(0,1,1) 1

(0,1,0) 2

(0,0,0) 3

(0,0,1) 4

(1,0,1) 5



Modulation Bit Symbol Parameter 1

(1,0,0) 6

(1,1,0) 7

NOTE

Table 20-3 lists all the modulation bits indicated by three bits. Symbol parameter 1 is a value correspondingto each modulation bit.

20.4.2 EGPRS Transmit PowerThis topic describes the transmit power used in EDGE in 8PSK modulation mode.

From the perspective of network operation, the EDGE transceiver must have the same spectrumfeatures as those of an ordinary transceiver. When sending the signals modulated in 8PSKmodulation mode, the EDGE transceiver uses the transmit power that is 2 dB–5 dB less than theaverage power in GMSK modulation mode. Thus, the requirements for spectrum can be met.

On the BCCH, the transmit power of the signals modulated in 8PSK modulation mode is at most4 dB less than the average transmit power modulated in GMSK modulation mode. On thetimeslot located before the BCCH/CCCH, the transmit power of the signals modulated in 8PSKmode is at most 2 dB less than that modulated in GMSK modulation mode.

20.4.3 MCS-1 to MCS-9 Coding SchemesThis topic describes MCS-1 to MCS-9 coding schemes. EDGE uses MCS-1 to MCS-9 codingschemes.

EDGE uses MCS-1 to MCS-9 coding schemes, as shown in Table 20-4.

Table 20-4 EDGE coding schemes

Coding Scheme Modulation Mode Number of Bits inthe Payload ofEach Burst

Rate (kbit/s)

MCS-9 8PSK 2 x 592 59.2

MCS-8 2 x 544 54.4

MCS-7 2 x 448 44.8

MCS-6 592544+48

29.627.2

MCS-5 448 22.4

MCS-4 GMSK 352 17.6

MCS-3 296272+24

14.813.6

MCS-2 224 11.2




Coding Scheme Modulation Mode Number of Bits inthe Payload ofEach Burst

Rate (kbit/s)

MCS-1 176 8.8

NOTE

For 544 + 48 and 272 + 24 in the previous table, 544 and 272 indicate the significant bits, and 48 and 24indicate the padding bits.

Figure 20-2 shows the comparison between the rate of a single GPRS channel and that of asingle EDGE channel.

Figure 20-2 Comparison of the rate between the GPRS single channel and the EDGE singlechannel

kbit/s60.0

50.0

40.0

30.0

20.0

10.0

0.0CS-1 CS-2 CS-3 CS-4 MCS-1 MCS-2 MCS-3 MCS-4 MCS-5MCS-6 MCS-7 MCS-8MCS-9

8.012.2 14.4

20.2

8.811.2

14.8 17.622.4

29.6

44.8

54.4

59.2

GPRSEDGE

GMSKmodulation

8PSKmodulation

20.4.4 Link Quality ControlThis topic describes the link quality control. The link quality control is the method of enablingthe system to adapt to the radio transmission environment dynamically in data transmissionthrough the change in modulation modes and coding modes so that the link quality can beimproved.

EDGE uses a set of high-efficient link quality control algorithm. EDGE has two link qualitycontrol modes: Link Adaptation (LA) and Incremental Redundancy (IR).

Basic Principle of LAOne data block can be divided into two. The TX party retransmits the original data blocks or thedata blocks that are generated from the original data blocks. The RX party does not need to cachethe incorrect data blocks received previously.

Basic Principle of IRIgnoring the radio transmission environment at first, the TX party uses a coding scheme totransmit data initially. In the coding scheme, the data rate is high and the capability to protect



data is weak. If the data is received incorrectly, the TX party retransmits the additional codinginformation. The RX party combines the new information with the history information, and thenperforms decoding. The previous process is repeated until the decoding succeeds.

In uplink data transmission, the system notifies an MS by default that the IR mode should beused. The notification is realized through RESEGMENT=0 (segmentation forbidden) carried inthe messages that are related to the assignment of the uplink resources. In IR mode, the RX partyshould have sufficient memory to save the history information. If the network memory isinsufficient, the TX party may notify the MS of the insufficiency through RESEGMENT=1carried in an UPLINK ACK/NACK message.

In downlink data transmission, if the memory of an MS is insufficient, the TX party can sendsMS OUT OF MEMORY to the network side through a DOWNLINK ACK/NACK message.The network side cannot use the IR mode in downlink.

20.4.5 Dynamic Addition of SubtimeslotsThis topic describes the dynamic addition of subtimeslots. The dynamic addition of subtimeslotsis a process in which several timeslots on the Abis interface are mapped to one traffic channel.Then, they are divided and combined on both the TX and the RX ends.

The data rate of each timeslot on the Abis interface is 16 kbit/s. In EDGE, the data rate can be59.2 kbit/s. In EDGE, the method of dynamically adding subtimeslots is the same as that inGPRS. In GPRS, each PDCH can add only one subtimeslot. In EDGE, each PDCH can add threesubtimeslots.

20.5 CapabilitiesThis topic describes the capabilities of EDGE.

The capabilities of EDGE are as follows:

l The BSC supports 256 E1 cables on the Pb interface.

l Each GMPS/GEPS subrack supports 64 E1 cables on the Pb interface.

l Each GEIUP/GOIUP supports 32 E1 cables on the Pb interface.

20.6 ImplementationThe EDGE implementation consists of configuring EDGE and disabling EDGE.

20.6.1 Configuring EGPRSThis topic describes how to configure EDGE on the BSC6000 Local Maintenance Terminal.

20.6.1 Configuring EGPRSThis topic describes how to configure EDGE on the BSC6000 Local Maintenance Terminal.

PrerequisiteNone




Procedure

Step 1 Configure idle timeslots for a site.1. On the Management Tree tab page of the BSC6000 Local Maintenance Terminal, right-

click the target BTS, and then choose Configure Site Idle Timeslot on the shortcut menu.A dialog box is displayed, as shown in Figure 20-3.

Figure 20-3 Configuring idle timeslots for a BTS

2. In the Idle Timeslot area, click the box under the Idle Timeslots area, and then enter thenumber of the configured idle timeslots.

3. Click Finish. A confirm dialog box is displayed.4. Click Yes to return to the previous dialog box, as shown in Figure 20-3.5. Click Finish. Idle timeslots are configured for the site.

Step 2 Configure a cell to make it support GPRS and EDGE.1. On the Management Tree tab page of the BSC6000 Local Maintenance Terminal, right-

click the target cell, and then choose Configure Cell Attributes on the shortcut menu. Adialog box is displayed, as shown in Figure 20-4.



Figure 20-4 Selecting a cell

2. Double-click the target cell in the Cell view list box to add it to the Selected cells list box.

3. Click Next. A dialog box is displayed, as shown in Figure 20-5.

Figure 20-5 Setting cells attributes

4. In the Cells to be set area, select the target cell, and then click Set Cell Properties. A dialogbox is displayed, as shown in Figure 20-6.




Figure 20-6 Set Cell Attributes dialog box

5. Select EDGE Support. Click OK. A dialog box is displayed, as shown in Figure 20-4.

NOTE

l If the GPRS is not configured, the system selects GPRS Support automatically. Then, you needto select PCU in the drop-down list box.

l In the dialog box shown in Figure 20-6, clear GPRS Support. EDGE is disabled.

6. Click Finish. EDGE is configured.

----End

20.7 Maintenance InformationThis topic describes the maintenance information on EDGE. The maintenance information onEDGE consists of information on alarms and on performance counters.



AlarmsAlarm ID Alarm Name

104 All PBSLs in the PCU Are Faulty

128 No Circuit Configured in the PCU

CountersTable 20-5 lists the performance counters involved in EDGE.

Table 20-5 Counters involved in EDGE

Counter Description

AR3015A: Mean Number of DynamicallyConfigured Channels (EDGE) (900/850Cell)

This counter indicates the mean number ofconfigured EDGE PDCHs in a GSM900/850cell of the BSC in a statistical period. Thisnumber contains the number of EDGEPDCHs that are dynamically converted fromdynamic EDGE PDCHs.

AR3015B: Mean Number of DynamicallyConfigured Channels (EDGE) (1800/1900Cell)

This counter indicates the mean number ofconfigured EDGE PDCHs in a DCS1800/PCS1900 cell of the BSC in a statisticalperiod. This number contains the number ofEDGE PDCHs that are dynamicallyconverted from dynamic EDGE PDCHs.

CR3015: Mean Number of DynamicallyConfigured Channels (EDGE)

This counter indicates the mean number ofconfigured EDGE PDCHs in all the cells ofthe BSC in real-time statistics. This numbercontains the number of EDGE PDCHs that aredynamically converted from dynamic EDGEPDCHs.

AR3025A: Mean Number of AvailableChannels (EDGE) (900/850 Cell)

This counter indicates the mean number ofavailable channels in a GSM900/850 cell ofthe BSC in a statistical period, with thechannel type of PDTCH, PBCCH+PDTCH,or PCCCH+PDTCH.

AR3025B: Mean Number of AvailableChannels (EDGE) (1800/1900 Cell)

This counter indicates the mean number ofavailable channels in a DCS1800/PCS1900cell of the BSC in a statistical period, with thechannel type of PDTCH, PBCCH+PDTCH,or PCCCH+PDTCH and the TRX type ofEDGE.




Counter Description

CR3025: Number of Available Channels(EDGE)

This counter indicates the number of availablechannels in all the cells of the BSC in real-timestatistics, with the channel type of PDTCH,PBCCH+PDTCH, or PCCCH+PDTCH andthe TRX type of EDGE.

R3006A: Number of Initially ConfiguredChannels (Static EDGE) (900/850 Cell)

This counter indicates the number ofconfigured static EDGE PDCHs in aGSM900/850 cell of the BSC at eachsampling point.

R3005B: Number of Initially ConfiguredChannels (Static EDGE) (1800/1900 MHzCell)

This counter indicates the number ofconfigured static EDGE PDCHs in aDCS1800/PCS1900 cell of the BSC at eachsampling point.

R3006A: Number of Initially ConfiguredChannels (Dynamic EDGE) (900/850 MHzCell)

This counter indicates the number ofconfigured dynamic EDGE PDCHs in aGSM900/850 cell of the BSC at eachsampling point. This number contains thenumber of dynamic EDGE PDCHs that aredynamically converted into TCHFs.

R3006B: Number of Initially ConfiguredChannels (Dynamic EDGE) (1800/1900MHz Cell)

This counter indicates the number ofconfigured dynamic EDGE PDCHs in aDCS1800/PCS1900 cell of the BSC at eachsampling point. This number contains thenumber of dynamic EDGE PDCHs that aredynamically converted into TCHFs.

CR3005: Number of Initially ConfiguredChannels (Static EDGE)

This counter indicates the number ofconfigured static EDGE PDCHs in all the cellsof the BSC at each sampling point.

CR3006: Number of Initially ConfiguredChannels (Dynamic EDGE)

This counter indicates the number ofconfigured dynamic EDGE PDCHs in all thecells of the BSC at each sampling point. Thisnumber contains the number of dynamicEDGE PDCHs that are dynamicallyconverted into TCHFs.

AL8351: Mean Number of Faulty Circuits onthe Pb Interface

This counter indicates the mean number offaulty circuits on the Pb interface.

AL8353: Mean Number of Blocked Circuitson the Pb Interface

This counter indicates the mean number ofblocked circuits on the Pb interface.

AL8354: Mean Number of Idle Circuits onthe Pb Interface

This counter indicates the mean number ofidle circuits on the Pb interface.

AL8355: Mean Number of Busy Circuits onthe Pb Interface

This counter indicates the mean number ofbusy circuits on the Pb interface.



Counter Description

AL8352: Mean Number of Circuits inMaintenance State on the Pb Interface

This counter indicates the mean number ofcircuits in maintenance state on the Pbinterface.

L0387: Total Number of Messages Receivedfrom PCU

This counter indicates the total number ofmessages that the BSC receives from all thePCUs on the Pb interface.

L8387: Messages Received from a PCU This counter indicates the number ofmessages that the BSC receives from a PCUon the Pb interface.

R3140: Requests for TCH from the PCU This counter indicates the number of requeststhat the BSC sends to the PCU for theconversion of PDCHs into TCHs.

R3141: Successful Requests for TCH fromthe PCU

This counter indicates the number ofsuccessful acknowledgments made by thePCU after the BSC retrieves dynamic PDCHsfrom the PCU.

AR3011A: Mean Number of DynamicallyConfigured Channels (PDCH) (900/850Cell)

This counter indicates the mean number ofconfigured PDCHs in a GSM900/850 cell ofthe BSC in a statistical period. This numbercontains the number of PDCHs that aredynamically converted from dynamicPDCHs.

AR3011B: Mean Number of DynamicallyConfigured Channels (PDCH) (1800/1900Cell)

This counter indicates the mean number ofconfigured PDCHs in a DCS1800/PCS1900cell of the BSC in a statistical period. Thisnumber contains the number of PDCHs thatare dynamically converted from dynamicPDCHs.

CR3011: Mean Number of DynamicallyConfigured Channels (PDCH)

This counter indicates the mean number ofconfigured PDCHs in all the cells of the BSCin real-time statistics. This number containsthe number of PDCHs that are dynamicallyconverted from dynamic PDCHs.

AR3021A: Mean Number of AvailableChannels (PDCH) (900/850 Cell)

This counter indicates the mean number ofavailable channels in a GSM900/850 cell ofthe BSC in a statistical period, with thechannel type of PDTCH, PBCCH+PDTCH,or PCCCH+PDTCH.

AR3021B: Mean Number of AvailableChannels (PDCH) (1800/1900 Cell)

This counter indicates the mean number ofavailable channels in a DCS1800/PCS1900cell of the BSC in a statistical period, with thechannel type of PDTCH, PBCCH+PDTCH,or PCCCH+PDTCH.




Counter Description

CR3021: Number of Available Channels(PDCH)

This counter indicates the number of availablechannels in all the cells of the BSC in real-timestatistics, with the channel type of PDTCH,PBCCH+PDTCH, or PCCCH+PDTCH.

R3001A: Number of Initially ConfiguredChannels (Static PDCH) (900/850 Cell)

This counter indicates the number ofconfigured static PDCHs in a GSM900/850cell of the BSC at each sampling point.

R3001B: Number of Initially ConfiguredChannels (Static PDCH) (1800/1900 MHzCell)

This counter indicates the number ofconfigured static PDCHs in a DCS1800/PCS1900 cell of the BSC at each samplingpoint.

R3002A: Number of Initially ConfiguredChannels (Dynamic PDCH) (900/850 MHzCell)

This counter indicates the number ofconfigured dynamic PDCHs in aGSM900/850 cell of the BSC at eachsampling point. This number contains thenumber of dynamic PDCHs that aredynamically converted into TCHFs.

R3002B: Number of Initially ConfiguredChannels (Dynamic PDCH) (1800/1900MHz Cell)

This counter indicates the number ofconfigured dynamic PDCHs in a DCS1800/PCS1900 cell of the BSC at each samplingpoint. This number contains the number ofdynamic PDCHs that are dynamicallyconverted into TCHFs.

CR3001: Number of Initially ConfiguredChannels (Static PDCH)

This counter indicates the number ofconfigured static PDCHs in all the cells of theBSC at each sampling point.

CR3002: Number of Initially ConfiguredChannels (Dynamic PDCH)

This counter indicates the number ofconfigured dynamic PDCHs in all the cells ofthe BSC at each sampling point. This numbercontains the number of dynamic PDCHs thatare dynamically converted into TCHFs.

ZTA331: Paging Requests on the AbisInterface per BSC (PS Service)

This counter indicates the total number ofpaging requests (PS services) on the Abisinterface in all the cells of a BSC.

ZTA301H: Immediate AssignmentCommands per BSC (PS Service)

This counter indicates the total number ofimmediate assignment messages (PSservices) in all the cells of a BSC.

ZTL3188D: PCH Overloads due to PSService Counted through the Indicationsfrom the Abis Interface per BSC

This counter indicates the total number ofPCH overloads (PS services) on the Abisinterface in all the cells of a BSC.



Counter Description

A331: Delivered Paging Messages for PSService

When an MS serves as the called party in PSservice, the SGSN sends a PAGING REQmessage to the PCU for the MS paging. ThePCU processes the message and sends aPACKET PAGING message to the BSC. TheBSC sends a PS PAGING CMD message tothe relevant cell based on the cellidentification tag in the message, and thentakes statistics of this counter for the cell.

ZTA308H: Immediate Assignment Requestsper BSC (PS Service)

When an MS serves as the called party in PSservice, the SGSN sends a PAGING REQmessage to the PCU for the MS paging. ThePCU processes the message and sends aPACKET PAGING message to the BSC. TheBSC sends a PS PAGING CMD message tothe relevant cell based on the cellidentification tag in the message, and thentakes statistics of this counter for the cell.

A031: SGSN-Initiated Paging Requests forPS Service

This counter indicates the number of packetpaging messages that the BSC receives fromthe SGSN. The SGSN sends packet pagingmessages to the BSC through the PCU. Thenthe BSC takes statistics of this counter.

L3188D: Number of PACKET CCCHLOAD IND messages received by the BSCfrom the Abis interface

This counter indicates the number ofPACKET CCCH LOAD IND messages thatthe BSC receives from the measured cell in astatistical period. The number equals thenumber of downlink CCCH (PCH) messagesthat the BTS receives from the BSC and thePCU. When detecting that the CCCHs for PSservices are overloaded, the BTS sends aPACKET CCCH LOAD IND message to theBSC. Then the BSC forwards the message tothe PCU.

20.8 References

3GPP TS 50.059: "Enhanced Data rates for GSM Evolution (EDGE); Project scheduling andopen issues for EDGE"




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