general packet radio services (gprs)
TRANSCRIPT
General Packet Radio Services (GPRS)Abstract
The purpose of this document is to describe the feature " General Packet Radio Services (GPRS)" from a data transcript point of view.
Contents
1 Revision Information
2 Description 2.1 General 2.2 GPRS system overview
3 Data Transcript Impacts 3.1 General 3.2 Packet Control Unit (PCU) 3.3 Description of DT example 3.4 APZ Size Alteration Events 3.5 APT Size Alteration Events 3.6 Traffic DT - BSC Exchange Properties 3.7 RP Database Table 3.8 How to enable Ethernet in the PCU 3.9 Allocation of RP 3.10 Allocation of EM 3.11 Insertion of CLM/SPM/TSM & Allocation of SNT 3.12 Digital Path, RALT, RTG, RTT & RBLT 3.13 CCITT7 Signalling 3.14 Deblocking of RP 3.15 Deblocking of EM, RPG's and RPP's 3.16 Deblocking of GS 3.17 Deblocking of the Gb-interface 3.18 Subfile 85xxx - Cell Data
4 Miscellaneous Information 4.1 Abbreviations
1 Revision Information This document has been revised due to the introduction of Fixed Size Alteration.
2 Description
2.1 General
GPRS is a standardized packet switched data service for GSM based systems. This feature helps the operator to make desired data services, i.e. e-mail, file transfer and Web browsing more efficient, allowing several users to share the same data channel. The GPRS feature enables a smooth and efficient introduction of internet services in the GSM network.
Benefits:
Suitable for bursty traffic as well as frequent traffic of small data volumes as e.g. Web browsing.
A number of users can share the same frequency carrier allowing a cost efficient use of radio resources and good service to the subscriber.
Cost efficient and fast introduction of GPRS due to reuse of existing RBS and BSC.
GPRS enables a co-existence of GSM and GPRS within the existing GSM infrastructure.
2.2 GPRS system overview
2.2.1 Serving GPRS Support Node (SGSN)
The Serving GPRS Support Node is a primary component in the GSM network using GPRS. This new node forwards incoming and outgoing IP packets addressed to/from an MS that is attached within the SGSN service area.
The SGSN handles packet routing and transfer to and from the SGSN service area. It serves all GPRS subscribers that are physically located within the geographical SGSN service area. A GPRS subscriber may be served by any SGSN in the GPRS network, all dependent on location. The traffic is routed from the SGSN to the BSC, via the BTS to the mobile station.
2.2.2 Gateway GPRS Support Node (GGSN)
The Gateway GPRS Support Node is the second new nodetype introduced to handle GPRS connections. The GGSN handles the interface to the external IP packet networks and acts like a router for the IP addresses of all GPRS subscribers in the network.
2.2.3 Connection to BSS
To be able to connect the new GPRS nodes to a GSM network, a new interface (Gb) is introduced in the BSC. New hardware is also introduced to handle the incoming and outgoing GPRS packets.
To connect the SGSN to the BSC the Gb interface is used. The connection can be direct to the BSC or via the MSC. The latter solution requires that all devices on the Gb interface is semipermanently connected through the MSC towards the BSC. See Figure 1.
Figure 1 Connection of SGSN to BSS
3 Data Transcript Impacts
3.1 General
The Capacity for circuit switched calls will be degraded due to GPRS. How much depends on the amount of GPRS traffic. The degradation is mostly because of channel allocation/deallocation as GPRS and circuit switched calls share the same resources hence complicates the allocation process. If a cell is expected to have much GPRS traffic, the number of timeslots on the radio interface used for GPRS traffic can be set to a fixed value. This will result in that the number of timeslots available for speech will be reduced by the same value. It is also possible to have the amount of GPRS timeslots dynamically allocated depending on the amount of circuit switched calls in the cell.
3.2 Packet Control Unit (PCU)
The PCU is situated in the BSC or BSC/TRC. It takes care of the connection to the Gb interface and functions as an interface between the Abis interface and the Gb interface. The PCU is equipped with two types of RP:s. The RP:s are of the type RP4 and RPP. The RP4 (RP 96&97 in the following example) is used only to connect the PCU to the serial RP bus. The RPP (RP 98&99 in the following example) is a new type of RP developed to handle the GPRS connections.
The most simple configuration is the single RPP PCU and consists of one RPP only. This RPP processes all GPRS protocols. Paging and access over CCCH must be done via the TRH. See Figure 2.
Figure 2 Single RPP PCU
If more than one RPP is used, the RPP:s will communicate with each other via an Ethernet bus situated in the back plane of the PCU magazine.
3.3 Description of DT example
The DT example in the following chapters describes the DT needed to define and integrate the PCU magazine. The PCU is here a multi RPP PCU equipped with 2 RPP:s. The example covers the definition of the complete PCU magazine including hardware, connections to SGSN and activation of the feature in the BSC.
The following Size Alteration Events are affected by this function :
3.4 APZ Size Alteration Events
SAE 807 , Block RPDI
SAE 304
SAE 1822
How to set the SAE number of individuals is described in document "Setting of Size Alteration Events in BSC/TRC" no. 105/19046-FAD 10406 , included in this DT-Infomodel.Two methods are described but we recommend that the Fixed SAE method is used.
3.5 APT Size Alteration Events
SAE 515 , Block DIPRTG
SAE 529 , Block ETRTG
SAE 500 , Block RTGLT
SAE 500 , Block HIDRTG
How to set the SAE number of individuals is described in document "Setting of Size Alteration Events in BSC/TRC" no. 105/19046-FAD 10406 , included in this DT-Infomodel.Two methods are described but we recommend that the Fixed SAE method is used.
3.6 Traffic DT - BSC Exchange Properties
A number of exchange properties are needed to configure GPRS correctly. The property ALPHA is a Power control parameter used for the GPRS connections.
RAEPC:PROP=ALPHA-0;
By setting the property CHCODING, the operator can choose between CS-1 (Coding Scheme) and CS-2 on a per BSC level. The maximum data rate will increase by using CS-2, however, all signalling uses CS-1 only. Note that older versions of RBS 2301 do not support CS-2.
Table 1 Description of CHANNELCODING
Property value Description
2 CS-2 is used (default)
1 CS-1 is usedRAEPC:PROP=CHCODING-2;
GPRSNWMODE is used to set the parameter NETWORK_OPERATION_MODE in the messages System Information type 13 and Packet System Information type 1. It is also used to control the creation of master channels.
RAEPP:ID=ALL;
Printout of properties
Table 2 Description of GPRSNWMODE
Property value Description
0 Network Mode of Operation I. No master PDCH exists.
1 Network Mode of Operation I. Master PDCH can exist.
2 Network Mode of Operation II. No master PDCH exists. (default)
3 Network Mode of Operation II. Master PDCH can exist.
RAEPC:PROP=GPRSNWMODE-2;
The property ONDEMANDGPHDEV is used for setting the number of reserved GPH devices in an RPP that can be used for on-demand PDCH only.
RAEPC:PROP=ONDEMANDGPHDEV-20;
The property PILTIMER is used for setting the Packet Idle List Timer. When an on-demand PDCH becomes idle it is placed in idle list for the packet switched domain and PILTIMER is started. When the PILTIMER expires for a PDCH the channel is returned to circuit switched domain. The value shall be given in multiples of 1 seconds.
RAEPC:PROP=PILTIMER-20;
The property TBFDLLIMIT is used for setting the Temporary Block Flow (TBF) downlink limit. TBFDLLIMIT is a preference parameter for the number of TBF in the downlink direction. The parameter shall be set according to the wanted number of TBF per PDCH before new on-demand PDCH shall be allocated from the CSD.
RAEPC:PROP=TBFDLLIMIT-2;
The property TBFULLIMIT is used for setting the Temporary Block Flow (TBF) uplink limit. TBFULLIMIT is a preference parameter for the number of TBF in the uplink direction. The parameter shall be set according to the wanted number of TBF per PDCH before new on-demand PDCH shall be allocated from the CSD.
RAEPC:PROP=TBFULLIMIT-2;
3.7 RP Database Table
Four new RP:s have been added in the DT to handle GPRS traffic. RP 96 and RP 97 are only handling the connection of the PCU to the serial RP bus. RP 98 and 99 handles the
actual GPRS traffic. The GB-interface is defined in an ordinary ETC magazine using RP=48 and RP=49.
DBTRI;DBTSI:TAB=RPSRPBSPOS, RPADDR=48, BRNO=1, MAGNO=07, SLOTNO=0, BUSCONN=YES;DBTSI:TAB=RPSRPBSPOS, RPADDR=49, BRNO=1, MAGNO=07, SLOTNO=19,BUSCONN=YES;
DBTSI:TAB=RPSRPBSPOS,RPADDR=96,BRNO=3,MAGNO=10, SLOTNO=0,BUSCONN=YES;DBTSI:TAB=RPSRPBSPOS,RPADDR=97,BRNO=3,MAGNO=10, SLOTNO=19,BUSCONN=YES;DBTRE:COM;
DBTRI;DBTSI:TAB=RPSRPBSPOS,RPADDR=98,BRNO=3,MAGNO=10, SLOTNO=3,BUSCONN=NO; !RPP!DBTSI:TAB=RPSRPBSPOS,RPADDR=99,BRNO=3,MAGNO=10, SLOTNO=15,BUSCONN=NO; !RPP!DBTRE:COM;DBTSP:TAB=AXEPARS; !Check that GPRS value = 1!
3.8 How to enable Ethernet in the PCU
3.8.1 Define an Ethernet Group
1) Block RP NET A and NET B in RPIG
BLRCI:GROUP=CHARLIE,NET=A;BLRCI:GROUP=CHARLIE,NET=B;
2) Define a RPIG
DBTRI;DBTSP:TAB=RPSRPIGOUPS;DBTSI:TAB=RPSRPIGROUPS,GROUP=CHARLIE,GROUPNO=1;DBTRE:COM;
3.8.2 Connect RPs to the Ethernet Group
1)Connect all RPs to be used with ethernet to the group
DBTRI;DBTSI:TAB=RPSRPIRPS,RPADDR=98,GROUP=CHARLIE;DBTSI:TAB=RPSRPIRPS,RPADDR=99,GROUP=CHARLIE;DBTRE:COM;DBTSP:TAB=RPSRPIRPS;
2)Deblock RP NET A and NET B in RPIG
BLRCE:GROUP=CHARLIE,NET=A;BLRCE:GROUP=CHARLIE,NET=B;
N.B. The RPPs will not be part of the ethernet until they are blocked and deblocked.
3.8.3 Check if Ethernet is Working
1) Check which RPs are up or down
DBTSP:TAB=RPSRPISUPERVS,GROUP=CHARLIE,RPADDR1=98,RPADDR2=99,NET=A;DBTSP:TAB=RPSRPISUPERVS,GROUP=CHARLIE,RPADDR1=98,RPADDR2=99,NET=B;
2) Check which RPs have state UP
DBTSP:TAB=RPSRPISUPERVS,GROUP=CHARLIE,STATE=UP;
3) Check which RPs have state DOWN
DBTSP:TAB=RPSRPISUPERVS,GROUP=CHARLIE,STATE=DOWN;
3.9 Allocation of RP
EXRPI:RP=48,RPT=49, TYPE=RP4S1A ; !RTG!EXRPI:RP=96,RPT=97, TYPE=RP4S1A;EXRPI:RP=98, TYPE=RPPS1;EXRPI:RP=99, TYPE=RPPS1;
EXRUI:RP=48,RPT=49, SUID="1/CAA 135 2517/RPMM R1A01";! RPMMR !EXRUI:RP=48,RPT=49, SUID="1/CAA 135 3024/ETRTG R2A01";! ETRTGR !EXRUI:RP=48,RPT=49, SUID="1/CAA 135 2518/RPMBH R1C02";! RPMBHR !EXRUI:RP=48,RPT=49, SUID="1/CAA 135 2509 R3A01";! REXR !EXRUI:RP=48,RPT=49, SUID="1/CAA 135 004/RPFD R3A01";! RPFDR !EXRUI:RP=48,RPT=49, SUID="1/CAA 135 005 R1A02";! TERTR !
EXRUI:RP=96,RPT=97, SUID="1/CAA 135 2517/RPMM R1A01";! RPMMR !EXRUI:RP=96,RPT=97, SUID="1/CAA 135 2518/RPMBH R1C02";! RPMBHR !EXRUI:RP=96,RPT=97, SUID="1/CAA 135 2509 R3A01";! REXR !EXRUI:RP=96,RPT=97, SUID="1/CAA 135 004/RPFD R3A01";! RPFDR !EXRUI:RP=96,RPT=97, SUID="1/CAA 135 005 R1A02";! TERTR !
EXRUI:RP=98, SUID="9000/CXC 146 03 R1A08"; ! RPIFDR !EXRUI:RP=98, SUID="9000/CXC 146 19 R1B03";! RPEXR !EXRUI:RP=98, SUID="9000/CXC 146 05 R1A03";! RPFDR !EXRUI:RP=98, SUID="9000/CXC 146 07 R1A03";! FSIR !EXRUI:RP=98, SUID ="CXC 146 1000 R7A02";! RGSERVR !EXRUI:RP=98, SUID ="CXC 146 1001 R8A02";! RGRLCR !EXRUI:RP=98, SUID ="CXC 146 1002 R2A04";! RTGPHDVR!EXRUI:RP=98, SUID ="CXC 146 1003 R4A02";! RTGBR !
EXRUI:RP=99, SUID="9000/CXC 146 03 R1A08";! RPIFDR !
EXRUI:RP=99, SUID="9000/CXC 146 19 R1B03";! RPEXR !EXRUI:RP=99, SUID="9000/CXC 146 05 R1A03";! RPFDR !EXRUI:RP=99, SUID="9000/CXC 146 07 R1A03";! FSIR !EXRUI:RP=99, SUID ="CXC 146 1000 R7A02";! RGSERVR !EXRUI:RP=99, SUID ="CXC 146 1001 R8A02";! RGRLCR !EXRUI:RP=99, SUID ="CXC 146 1002 R2A04";! RTGPHDVR!EXRUI:RP=99, SUID ="CXC 146 1003 R4A02";! RTGBR !
3.10 Allocation of EM
EXEMI:EQM=ETRTG-0&&-31 ,RP=48 ,RPT=49 ,EM= 6;EXEMI:EQM=ETRTG-32&&-63 ,RP=49 ,RPT=48 ,EM= 7;
EXEMI:SUID="CXC1461000R7A02", RP=98,EQM=RGSERV-0, EM=0;EXEMI:SUID="CXC1461003R4A02", RP=98,EQM=RTGB-0, EM=1;EXEMI:SUID="CXC1461002R2A04", RP=98,EQM=RTGPHDV-0&&-63, EM=2;EXEMI:SUID="CXC1461001R8A02", RP=98,EQM=RGRLC-0, EM=3;
EXEMI:SUID="CXC1461000R7A02", RP=99,EQM=RGSERV-1, EM=0;EXEMI:SUID="CXC1461003R4A02", RP=99,EQM=RTGB-1, EM=1;EXEMI:SUID="CXC1461002R2A04", RP=99,EQM=RTGPHDV-64&&-127,EM=2;EXEMI:SUID="CXC1461001R8A02", RP=99,EQM=RGRLC-1, EM=3;
3.11 Insertion of CLM/SPM/TSM & Allocation of SNT
NTCOI:SNT=ETRTG-0, SNTV=1, SNTP=TSM-9-6;NTCOI:SNT=ETRTG-1, SNTV=1, SNTP=TSM-9-7;
NTCOI:SNT=RTGPHDV-0, SNTV=1, SNTP=TSM-29-1;NTCOI:SNT=RTGPHDV-1, SNTV=1, SNTP=TSM-29-2;
NTCOI:SNT=RTGPHDV-2, SNTV=1, SNTP=TSM-29-13;NTCOI:SNT=RTGPHDV-3, SNTV=1, SNTP=TSM-29-14;
EXDUI:DEV=RTGLT-1&&-31;EXDUI:DEV=RTGLT-33&&-63;
EXDUI:DEV=RTGPHDV-0&&-31; ! RPP !EXDUI:DEV=RTGPHDV-32&&-63; ! RPP !
EXDUI:DEV=RTGPHDV-64&&-95; ! RPP !EXDUI:DEV=RTGPHDV-96&&-127; ! RPP !
3.12 Digital Path, RALT, RTG, RTT & RBLT
DTDII:DIP=0RTGLT,SNT=ETRTG-0;DTDII:DIP=1RTGLT,SNT=ETRTG-1;
DTIDC:DIP=0RTGLT,MODE=0,INACT=0,MULTFS=00,CRC=0;
DTIDC:DIP=1RTGLT,MODE=0,INACT=0,MULTFS=00,CRC=0;
3.13 CCITT7 Signalling
The Network Service Identity is defined with the command RRNEI. This identifies each BSC to the SGSN.
RRNEI:NSEI=1;
3.14 Deblocking of RP
BLRPE:RP=48;BLRPE:RP=49;
BLRPE:RP=96;BLRPE:RP=97;
3.15 Deblocking of EM, RPG's and RPP's
BLEME:RP=48, EM=6;BLEME:RP=49, EM=7;
BLEME:RP=98, EM=0;BLEME:RP=98, EM=1;BLEME:RP=98, EM=2;BLEME:RP=98, EM=3;
BLEME:RP=99, EM=0;BLEME:RP=99, EM=1;BLEME:RP=99, EM=2;BLEME:RP=99, EM=3;
BLRPE:RP=98; ! RPP !BLRPE:RP=99; ! RPP !
3.16 Deblocking of GS
NTBLE:SNT=ETRTG-0;NTBLE:SNT=ETRTG-1;
NTBLE:SNT=RTGPHDV-0; ! RPP (98) !NTBLE:SNT=RTGPHDV-1; ! RPP (99) !
NTBLE:SNT=RTGPHDV-2; ! RPP (98) !NTBLE:SNT=RTGPHDV-3; ! RPP (99) !
3.17 Deblocking of the Gb-interface
DTBLE:DIP=0RTGLT;DTBLE:DIP=1RTGLT;
A Network Service Virtual Connection is defined with the command RRNSI. This will result in a wideband semipermanent connection between the specified ETC devices (1-31 & 33-63) and the automatically selected GPRS Packet Handler devices (RTGPHDV).
RRNSI:DEV=RTGLT-1 ,NSVCI=1 ,DLCI=16 ,NUMDEV=31;RRNSI:DEV=RTGLT-33 ,NSVCI=2 ,DLCI=17 ,NUMDEV=31;
RRVBE:NSVCI=1;RRVBE:NSVCI=2;
EXDAI:DEV=RTGLT-1&&-31;EXDAI:DEV=RTGLT-33&&-63;
EXDAI:DEV=RTGPHDV-0&&-31; ! RPP !EXDAI:DEV=RTGPHDV-32&&-63; ! RPP !
EXDAI:DEV=RTGPHDV-64&&-95; ! RPP !EXDAI:DEV=RTGPHDV-96&&-127; ! RPP !
BLODE:DEV=RTGLT-1&&-31;BLODE:DEV=RTGLT-33&&-63;
BLODE:DEV=RTGPHDV-0&&-31;BLODE:DEV=RTGPHDV-32&&-63;
BLODE:DEV=RTGPHDV-64&&-95;BLODE:DEV=RTGPHDV-96&&-127;
RABLC:DETY=RTGLT, LVB=16& 32& 48 , ACL=A3;RABLI:DETY=RTGLT;
3.18 Subfile 85xxx - Cell Data
GPRS is activated in the cells with command RLGSI. The number of fixed Packet Data Channels is here set to 0 which means that all TS are allocated dynamically between circuit switch and packet switch connections.
RLGSI:CELL=KISTA1A;RLGSI:CELL=KISTA1B;RLGSI:CELL=KISTA1C;
RLGSC:CELL=KISTA1A, FPDCH=0, GAMMA=31;RLGSC:CELL=KISTA1B, FPDCH=0, GAMMA=31;RLGSC:CELL=KISTA1C, FPDCH=0, GAMMA=31;
4 Miscellaneous Information
4.1 Abbreviations
BSC Base Station ControllerBTS Base Transceiver StationCCCH Common Control ChannelCSD The domain where circuit switched calls are handled (speech, data, signalling). GGSN Gateway GPRS Support NodeGPRS General Packet Radio ServicesIP Internet ProtocolLAN Local Area NetworkPCU Packet Control UnitRBS Radio Base StationSGSN Serving GPRS Support NodeSNT Switching Network TerminalTBF Temporary Block Flow. A PS connection, that can be either uplink or downlink.TRC Transceiver ControllerTRH Transceiver HandlerWAN Wide Area Network