Gprs

GERAN

InformationSystem

GPRS/EGPRS Global Description

A50016-G5100-A024-01-7618

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f Important Notice on Product SafetyDANGER - RISK OF ELECTRICAL SHOCK OR DEATH - FOLLOW ALL INSTALLATION INSTRUCTIONS.The system complies with the standard EN 60950 / IEC 60950. All equipment connected to the system must comply with the applicable safety standards.Hazardous voltages are present at the AC power supply lines in this electrical equipment. Some components may also have high operating temperatures.Failure to observe and follow all installation and safety instructions can result in serious personal injury or property damage.Therefore, only trained and qualified personnel may install and maintain the system.

The same text in German:Wichtiger Hinweis zur ProduktsicherheitLEBENSGEFAHR - BEACHTEN SIE ALLE INSTALLATIONSHINWEISE.Das System entspricht den Anforderungen der EN 60950 / IEC 60950. Alle an das System angeschlossenen Gerte mssen die zutreffenden Sicherheitsbestimmungen erfllen.In diesen Anlagen stehen die Netzversorgungsleitungen unter gefhrlicher Spannung. Einige Komponenten knnen auch eine hohe Betriebstemperatur aufweisen.Nichtbeachtung der Installations- und Sicherheitshinweise kann zu schweren Krperverletzungen oder Sachschden fhren.Deshalb darf nur geschultes und qualifiziertes Personal das System installieren und warten.

Caution:This equipment has been tested and found to comply with EN 301489. Its class of conformity is defined in table A30808-X3247-X910-*-7618, which is shipped with each product. This class also corresponds to the limits for a Class A digital device, pursuant to part 15 of the FCC Rules.These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment.This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accor-dance with the relevant standards referenced in the manual Guide to Documentation, may cause harmful inter-ference to radio communications.For system installations it is strictly required to choose all installation sites according to national and local require-ments concerning construction rules and static load capacities of buildings and roofs.For all sites, in particular in residential areas it is mandatory to observe all respectively applicable electromagnetic field / force (EMF) limits. Otherwise harmful personal interference is possible.

Trademarks:All designations used in this document can be trademarks, the use of which by third parties for their own purposes could violate the rights of their owners.

Copyright (C) Siemens AG 2006Issued by the Communications GroupHofmannstrae 51D-81359 Mnchen

Technical modifications possible.Technical specifications and features are binding only insofar as they are specifically and expressly agreed upon in a written contract.

Copyright (C) Siemens AG 2006Issued by the Communications GroupHofmannstrae 51D-81359 Mnchen

Technical modifications possible.Technical specifications and features are binding only insofar as they are specifically and expressly agreed upon in a written contract.

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Table of ContentsThis document has 395 pages.

Reason for Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.1 Generality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.2 Structure of the Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2 GPRS/EGPRS Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192.1 GPRS and EGPRS Modulation Principles . . . . . . . . . . . . . . . . . . . . . . . . . 202.2 Network Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222.3 GPRS/EGPRS supported by satellite links . . . . . . . . . . . . . . . . . . . . . . . . . 252.3.1 Abis Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252.4 GPRS/EGPRS Protocol Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262.5 Data Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272.6 RLC/MAC Block and Radio Block Structures . . . . . . . . . . . . . . . . . . . . . . . 302.6.1 RLC/MAC and Radio Block Structures: Data Transfer . . . . . . . . . . . . . . . . 302.6.1.1 RLC/MAC Block and Radio Block Structures for GPRS Data Transfer . . . 312.6.1.2 RLC/MAC Block and Radio Block Structure for EGPRS Data Transfer . . . 312.6.2 RLC/MAC Block Structure: Control Signalling . . . . . . . . . . . . . . . . . . . . . . 33

3 Radio Interface Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343.1 GPRS/EGPRS Physical Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353.2 Channel Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363.2.1 GPRS Channel Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363.2.2 EGPRS Channel Coding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423.3 Temporary Block Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483.3.1 Extended Uplink Temporary Block Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . 493.3.2 Multiplexing MSs on the same PDCH: Downlink Direction . . . . . . . . . . . . . 513.3.3 Multiplexing MSs on the same PDCH: Uplink Direction . . . . . . . . . . . . . . . 523.3.4 Multiplexing MSs on the same PDCH: Configuration . . . . . . . . . . . . . . . . . 543.4 GPRS/EGPRS Logical Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553.4.1 Packet Broadcast Control Channel (PBCCH). . . . . . . . . . . . . . . . . . . . . . . 553.4.2 Packet Common Control Channel (PCCCH) . . . . . . . . . . . . . . . . . . . . . . . 573.4.3 Packet Data Traffic Channel (PDTCH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 593.4.4 Packet Dedicated Control Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 593.4.5 Coding of GPRS/EGPRS Logical Channels . . . . . . . . . . . . . . . . . . . . . . . . 603.5 Mapping of Logical Channels onto Physical Channels . . . . . . . . . . . . . . . . 603.5.1 PDCH without the Specific GPRS/EGPRS Signalling . . . . . . . . . . . . . . . . 613.5.2 PDCH Carrying both PBCCH and PCCCH. . . . . . . . . . . . . . . . . . . . . . . . . 613.5.3 PDCH Carrying PCCCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633.6 Packet Timing Advance Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643.6.1 Initial Timing Advance Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643.6.2 Continuous Timing Advance Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653.7 Multislot Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663.7.1 Mobile Station Classes for Multislot Capabilities . . . . . . . . . . . . . . . . . . . . 673.7.2 Mapping of Uplink Packet Traffic Logical Channels . . . . . . . . . . . . . . . . . . 693.7.3 Mapping of Downlink Packet Traffic Logical Channels . . . . . . . . . . . . . . . . 69

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4 Radio Resources Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 704.1 Radio Channel Allocation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714.2 Radio Resource Allocation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714.3 Multiband Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784.4 Dual Band Standard Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794.5 Enabling Packet Switched Services in a Cell. . . . . . . . . . . . . . . . . . . . . . . . 814.5.1 Aspects Related to Carrier Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . 824.6 Configuration of GPRS Channels in a Cell . . . . . . . . . . . . . . . . . . . . . . . . . 844.7 Management of Packet Data Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 874.7.1 Generalities about Resource Assignments . . . . . . . . . . . . . . . . . . . . . . . . . 874.7.2 Horizontal/Vertical Allocation Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . 904.7.2.1 Vertical Allocation Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904.7.2.2 Horizontal Allocation Strategy (HA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 914.7.2.3 Switching between VA and HA According to Radio Conditions. . . . . . . . . . 924.7.2.4 Switching between VA and HA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 944.7.2.5 Allocation of Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 954.7.3 Extended Dynamic Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 964.7.4 Management of Incoming GPRS/EGPRS Requests . . . . . . . . . . . . . . . . . 1034.7.4.1 PCU Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1054.7.4.2 BSC Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1114.7.5 Upgrading Strategies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1164.7.5.1 Upgrade of Radio Resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1164.7.5.2 Upgrade of Abis Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1194.7.6 Incoming Circuit Switched Calls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1204.7.7 Waiting Queue Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1204.7.7.1 Preemption of PDCH Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1224.7.7.2 Preemption of PDT Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1224.7.7.3 Allocation Retention Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1234.7.7.4 Forced Intracell Handovers of already established CS Calls . . . . . . . . . . . 1254.7.8 Flexible USF Granularity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

5 Hardware and Software Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1285.1 Supported BSC Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1295.1.1 BSC/72. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1295.1.2 BSC/120. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1315.1.3 eBSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1335.1.4 BSC1 Redundancy and Configuration Rules. . . . . . . . . . . . . . . . . . . . . . . 1355.1.5 Central Network Service Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1355.2 BTS Equipment Supporting GPRS and EGPRS . . . . . . . . . . . . . . . . . . . . 1385.3 PCU Frames and Dynamic Allocation on the Abis Interface . . . . . . . . . . . 1395.3.1 Concatenated PCU Frames. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1415.3.2 Flexible Abis Allocation and Concatenated PCU Frames . . . . . . . . . . . . . 1455.3.3 Configuration of Abis Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1475.3.4 Flexible Abis Allocation Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1485.3.5 Abis over satellite links. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1515.4 Packet Switched Services Supported on CCCH/PCCCH . . . . . . . . . . . . . 151

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6 Gb Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1546.1 Physical Layer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1556.2 Network Service Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1606.2.1 Sub-Network Service: Frame Relay on Gb Interface . . . . . . . . . . . . . . . . 1606.2.1.1 Examples of Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1626.2.1.2 Frame Relay Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1676.2.1.3 Procedures for PVCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1706.2.2 Network Service Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1726.2.2.1 Load Sharing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1726.2.2.2 Control Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1736.3 BSSGP Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1746.3.1 BSSGP Addressing: BSSGP Virtual Connections (BVCs) . . . . . . . . . . . . 1746.3.1.1 BVC Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1786.3.2 Quality of Service (QoS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1786.3.3 SGSN-BSS Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1796.3.3.1 MS Flow Control Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1826.3.3.2 BVC Flow Control Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1856.3.3.3 Flow Control sending criteria (for both BVC and MS) . . . . . . . . . . . . . . . . 1896.3.4 Multiple PCU Pooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1916.3.4.1 Paging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1946.3.4.2 Suspend/Resume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1956.3.4.3 Flush LL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1956.3.4.4 BSS Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1966.3.4.5 Dynamic Cell Allocation and Load Balancing . . . . . . . . . . . . . . . . . . . . . . 1966.3.5 Enhanced Flow Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1966.3.6 Quality Control Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2026.4 High Speed Gb Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2056.4.1 Gb over IP protocol Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2066.4.2 BSC Hardware and Upgrade Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . 2096.5 Flexible Gb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2106.6 Gb Streaming Enhancements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

7 Load Control for Packet Switched Services . . . . . . . . . . . . . . . . . . . . . . . 2177.1 Dynamic PTPPKF Reconfiguration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2177.1.1 System Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2197.1.2 Creation of a PCU Object and Enabling a NSVC for It . . . . . . . . . . . . . . . 2207.1.3 PCU Not Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2237.1.4 PCU Comes Back in Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2247.1.5 Time Needed to Execute PTPPKF Reconfiguration . . . . . . . . . . . . . . . . . 2267.2 PCU Overload Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

8 GPRS/EGPRS Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2288.1 Mobile Stations for Packet Switched Services . . . . . . . . . . . . . . . . . . . . . 2288.2 Network Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2288.3 Mobility Management Functionalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2308.3.1 Mobility Management States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2308.3.1.1 IDLE State. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2308.3.1.2 STAND-BY State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231

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8.3.1.3 READY State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2328.3.2 Mobility Management Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2338.3.2.1 Attach Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2338.3.2.2 Detach Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2348.4 Radio Resource Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2358.4.1 Packet Idle State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2358.4.2 Packet Transfer State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2358.5 Correspondence between RR States and MM States . . . . . . . . . . . . . . . . 2368.6 Packet Data Protocol Functionalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2368.6.1 INACTIVE State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2368.6.2 ACTIVE State. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2378.7 Activation and Deactivation of a PDP Context . . . . . . . . . . . . . . . . . . . . . . 2378.7.1 PDP Context Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2388.7.2 PDP Context Deactivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2398.7.3 One Time Slot for MM and SM procedures . . . . . . . . . . . . . . . . . . . . . . . . 2398.8 Access to the Network (Establishment of a TBF). . . . . . . . . . . . . . . . . . . . 2398.8.1 Medium Access Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2408.8.2 TBF Establishment Initiated by the MS on CCCH/PCCCH . . . . . . . . . . . . 2408.8.2.1 8 Bit or 11 Bit Uplink Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2418.8.2.2 Establishment using a One Phase Access . . . . . . . . . . . . . . . . . . . . . . . . 2428.8.2.3 TBF Establishment using a Two Phases Access. . . . . . . . . . . . . . . . . . . . 2438.8.2.4 TBF Establishment for EDGE Mobile Stations. . . . . . . . . . . . . . . . . . . . . . 2458.8.2.5 Contention Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2478.8.2.6 Uplink Access on PRACH (Access Persistence Control). . . . . . . . . . . . . . 2478.8.3 TBF Establishment Initiated by the Network on CCCH/PCCCH . . . . . . . . 2498.8.3.1 Network Operation Modes for Paging . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2508.8.3.2 Discontinuous Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2518.8.4 Relative Reserved Block Period Field (RRBP) . . . . . . . . . . . . . . . . . . . . . 2548.8.5 Polling Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2558.9 RLC Data Block Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2568.9.1 Acknowledged Mode for RLC/MAC Operation. . . . . . . . . . . . . . . . . . . . . . 2568.9.1.1 GPRS Acknowledged Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2568.9.1.2 EGPRS Acknowledged Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2578.9.2 Unacknowledged Mode for RLC/MAC Operation . . . . . . . . . . . . . . . . . . . 2598.9.3 Operations on Uplink TBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2598.9.3.1 Uplink TBF Using the Acknowledged Mode. . . . . . . . . . . . . . . . . . . . . . . . 2598.9.3.2 Uplink TBF Using the Unacknowledged Mode. . . . . . . . . . . . . . . . . . . . . . 2618.9.3.3 Anomalies During an Uplink TBF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2618.9.3.4 Release of an Uplink TBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2628.9.4 Operations on Downlink TBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2658.9.4.1 Acknowledged and Unacknowledged Modes on Downlink TBFs . . . . . . . 2658.9.4.2 Release of a Downlink TBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2668.9.5 Notes About Concurrent TBFs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2698.9.6 Suspend/Resume Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2708.9.7 GPRS/EGPRS TBF Scheduling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2738.9.7.1 Supported QoS Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2748.9.7.2 Scheduling Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

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8.9.8 Uplink Incremental Redundancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2768.9.9 EGPRS/GPRS Scheduler Enhancements for Rel5 Qos Support . . . . . . . 2788.10 Quality of Service Support for Packed Switched Services . . . . . . . . . . . . 2838.10.1 QoS and RRM procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2858.10.2 Quality of Service Improvements: Real Time TBF Multiplexing . . . . . . . . 2958.10.3 QoS and BSS impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2998.11 EGPRS/GPRS on Extended Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2998.11.1 Assignment of resources on extended cells . . . . . . . . . . . . . . . . . . . . . . . 3018.11.2 TAI Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3028.11.3 Time Offset values in Abis Downlink PCU frames . . . . . . . . . . . . . . . . . . 3038.11.4 Timing Advance Update in Extended Cell . . . . . . . . . . . . . . . . . . . . . . . . 3038.11.5 Transition between near and far Area. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3038.11.6 Extended Cells and Radio Resource Manager. . . . . . . . . . . . . . . . . . . . . 304

9 GPRS/EGPRS Functionalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3059.1 Cell Selection and Re-selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3059.1.1 Measurements for Cell Selection and Re-selection . . . . . . . . . . . . . . . . . 3069.1.2 Cell selection and Re-selection Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . 3079.1.2.1 GPRS/EGPRS Path Loss Criterion (C1 Criterion) . . . . . . . . . . . . . . . . . . 3079.1.2.2 C31 Criterion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3099.1.2.3 C32 Criterion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3119.1.3 Cell Re-selection Algorithm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3129.1.4 Management of GPRS/EGPRS Neighboring Cells. . . . . . . . . . . . . . . . . . 3149.1.4.1 Handling of Neighboring Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3149.1.4.2 GPRS/EGPRS Neighboring Cells and Involved Parameters . . . . . . . . . . 3169.1.4.3 Configuration of an Adjacent Cell supporting GPRS . . . . . . . . . . . . . . . . 3189.1.4.4 Configuration of an Adjacent Cell not supporting GPRS . . . . . . . . . . . . . 3189.1.5 Abnormal Cell Re-selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3199.2 Network Assisted Cell Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3209.3 External Network Assisted Cell Change . . . . . . . . . . . . . . . . . . . . . . . . . . 3249.4 Cell Re-selection from GSM/GPRS/EGPRS Network to UMTS Network . 3269.4.1 GSM-UMTS Re-selection Algorithm: Circuit Switched Case . . . . . . . . . . 3269.4.2 GSM-UMTS Re-selection Algorithm: Packet Switched Case . . . . . . . . . . 3289.4.3 Handling of UMTS Neighboring Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3299.5 Network Controlled Cell Reselection and Traffic Control Management . . 3309.5.1 Network Controlled Cell Reselection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3319.5.1.1 Measurement Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3349.5.1.2 Radio Link Network Controlled Cell Reselection Algorithm . . . . . . . . . . . 3359.5.2 NC Cell Reselection due to sufficient UMTS coverage. . . . . . . . . . . . . . . 3389.5.2.1 Enhancement of the NCCR G->G algorithm. . . . . . . . . . . . . . . . . . . . . . . 3459.5.3 GPRS/EGPRS Traffic Control Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . 3489.5.3.1 Network Controlled Cell Reselection Algorithm . . . . . . . . . . . . . . . . . . . . 3489.6 Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3519.6.1 Power Control Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3519.6.2 Measurement at the MS Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3539.6.2.1 Packet Idle Mode: Measurements for Power Control . . . . . . . . . . . . . . . . 3539.6.2.2 Packet Transfer Mode: Measurements for Power Control . . . . . . . . . . . . 3549.6.2.3 Derivation of Channel Quality Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

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9.6.3 BTS Output Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3559.6.4 DTM Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3569.7 Mobile Station Overheating Management . . . . . . . . . . . . . . . . . . . . . . . . . 3579.8 Link Adaptation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3629.8.1 Link Adaptation for GPRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3649.8.1.1 GPRS: Switching Points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3649.8.1.2 Quality Traps Disadvantage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3669.8.1.3 GPRS: Link Adaptation Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3679.8.2 Link Adaptation for EGPRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3689.8.2.1 EGPRS: Switching Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3689.8.2.2 EGPRS: Link Adaptation Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3739.8.3 Selection of the Candidate Initial Coding Scheme. . . . . . . . . . . . . . . . . . . 377

10 Managed Objects and attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

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List of FiguresFigure 1 Basic GMSK Constellation of Signal Vectors. . . . . . . . . . . . . . . . . . . . . 20Figure 2 Basic 8 PSK Constellation of Signal Vectors . . . . . . . . . . . . . . . . . . . . . 21Figure 3 GPRS/EGPRS Network Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . 22Figure 4 Protocol Stack for Data Transmission in GPRS/EGPRS Network. . . . . 26Figure 5 Data Flow across Protocol Layers in case of GPRS/ EG-

PRS(MSC1...MSC6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Figure 6 Data Flow across Protocol Layers in case of EGPRS(MSC7..MSC9). . 28Figure 7 Data Flow from the SGSN up to the Mobile Station. . . . . . . . . . . . . . . . 30Figure 8 RLC/MAC blocks structure for Data Transfer . . . . . . . . . . . . . . . . . . . . 31Figure 9 Radio Block structure for Data Transfer on the Um Interface . . . . . . . 31Figure 10 RLC/MAC Block structure with one RLC Data Block field . . . . . . . . . . . 31Figure 11 RLC/MAC Block structure with two RLC Data block fields . . . . . . . . . . 32Figure 12 Radio Block for Data Transfer with one RLC Data Block field . . . . . . . . 32Figure 13 Radio Block for Data Transfer with two RLC Data Block field . . . . . . . . 32Figure 14 RLC/MAC Block Structure for Control Messages . . . . . . . . . . . . . . . . . 33Figure 15 Radio Block for Control Messages (signalling) . . . . . . . . . . . . . . . . . . . 33Figure 16 Packet Data Channel (PDCH) within a TDMA frame. . . . . . . . . . . . . . . 35Figure 17 Multiframe Structure for a PDCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Figure 18 GPRS Coding Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Figure 19 Coding of the RLC/MAC Block using CS-1 . . . . . . . . . . . . . . . . . . . . . . 40Figure 20 EGPRS Coding Schemes and Families. . . . . . . . . . . . . . . . . . . . . . . . . 44Figure 21 Interleaving of MCS9 Coded Data into Two Consecutive Normal Bursts46Figure 22 Interleaving of MCS6 Coded Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Figure 23 Multiplexing Mobile Station on the same PDCH (Downlink) . . . . . . . . . 51Figure 24 Multiplexing Mobile Station on the same PDCH (Uplink). . . . . . . . . . . . 52Figure 25 Example of Mapping of the PBCCH Channel . . . . . . . . . . . . . . . . . . . . 56Figure 26 Packet Common Control Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Figure 27 Example of Mapping of the PCCCH Channel. . . . . . . . . . . . . . . . . . . . . 58Figure 28 Example of Mapping of two PCCCH Channels . . . . . . . . . . . . . . . . . . . 58Figure 29 Mapping of Logical Channels into DL Physical Channel . . . . . . . . . . . . 61Figure 30 Mapping of Logical Channels into UL Physical Channel . . . . . . . . . . . . 61Figure 31 Example of DL Configuration with PBCCH and PCCCH Channels . . . . 62Figure 32 Example of Uplink Configuration with PRACH Channel. . . . . . . . . . . . . 63Figure 33 Continuous Timing Advance Update Feature . . . . . . . . . . . . . . . . . . . . 66Figure 34 Example of Multislot Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68Figure 35 Multiband GSM mobile network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78Figure 36 Example of GPRS/EGPRS configuration. . . . . . . . . . . . . . . . . . . . . . . . 86Figure 37 Example of Vertical Allocation strategy . . . . . . . . . . . . . . . . . . . . . . . . . 90Figure 38 Example of the Horizontal Allocation Algorithm. . . . . . . . . . . . . . . . . . . 91Figure 39 Example of a Cell Configured with Five TRXs. . . . . . . . . . . . . . . . . . . . 93Figure 40 Channel Allocation Algorithms Flow Chart (CAA) . . . . . . . . . . . . . . . . . 97Figure 41 MS configuration block in CAA algorithm. . . . . . . . . . . . . . . . . . . . . . . . 98Figure 42 Allocations in Free Capacity region . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99Figure 43 Resource Reallocation Process and Functional Entities affected . . . . 102Figure 44 Allocation Algorithm implemented in PCU . . . . . . . . . . . . . . . . . . . . . . 110Figure 45 Allocation Algorithm implemented in the TDPC (AP in the eBSC). . . . 115

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Figure 46 EGPRS/GPRS BSS Hardware and Software Entities . . . . . . . . . . . . . 128Figure 47 BSC/72 Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130Figure 48 BSC/120 Rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133Figure 49 eBSC Upper Shelf. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134Figure 50 Central Network Service Layer Architecture (for the BSC1) . . . . . . . . . 136Figure 51 Fundamental Principle of Concatenated PCU Frames . . . . . . . . . . . . . 141Figure 52 Abis Mapping for a DL MCS9 radio block . . . . . . . . . . . . . . . . . . . . . . . 144Figure 53 Relationship between PCU Frames and Abis Allocation . . . . . . . . . . . 145Figure 54 PCU Frames and Abis Allocation Relationship (BSS < BR8.0) . . . . . . 146Figure 55 BTSE not supporting the Abis Dynamic Allocation . . . . . . . . . . . . . . . . 147Figure 56 Mapping of CCCH/PCCCH Channels on the Abis Interface. . . . . . . . . 152Figure 57 CCCH/PCCCH BSC1 Message Handling. . . . . . . . . . . . . . . . . . . . . . . 153Figure 58 Gb Interface: Protocol Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154Figure 59 Connection Types between BSC and SGSN . . . . . . . . . . . . . . . . . . . . 155Figure 60 Example of Frame Relay Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157Figure 61 Example of Frame Relay Link (GTS=3). . . . . . . . . . . . . . . . . . . . . . . . . 158Figure 62 Example of Frame Relay Link (GTS=3&4&5&6). . . . . . . . . . . . . . . . . . 159Figure 63 Example of Frame Relay Link (GTS=3&4&7&8). . . . . . . . . . . . . . . . . . 159Figure 64 Network Service Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160Figure 65 Gb Interface in a Frame Relay Network . . . . . . . . . . . . . . . . . . . . . . . . 161Figure 66 Creation of a NSVC object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163Figure 67 BSC Configured with One PCU and Two FR Links (64 kbit/s each). . . 164Figure 68 BSC supporting 1 PCU and 2 FR Links . . . . . . . . . . . . . . . . . . . . . . . . 165Figure 69 BSC Configured with Two PCUs and Two FR Links each one. . . . . . . 166Figure 70 Frame Relay Network Connecting two DTE Devices . . . . . . . . . . . . . . 168Figure 71 Frame Relay Frame Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169Figure 72 Periodic Polling Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171Figure 73 Distribution of Packet Switched Data Traffic among Different Cells . . . 177Figure 74 Cascaded Flow Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180Figure 75 Token Leaky Bucket (in the SGSN network node) . . . . . . . . . . . . . . . . 181Figure 76 Closed Loop Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181Figure 77 Example Cell Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187Figure 78 Message: MS-FLOW-CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190Figure 79 SGSN does not answer with the message: MS-FLOW-CONTROL . . . 190Figure 80 Closed-loop control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198Figure 81 BSSGP Flow Control Level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199Figure 82 Example of TBF Establishment and TBF Reconfiguration . . . . . . . . . . 200Figure 83 Example of messages in case of TBF Release . . . . . . . . . . . . . . . . . . 201Figure 84 QCF and PFC Flow Control processes. . . . . . . . . . . . . . . . . . . . . . . . . 203Figure 85 Uplink guaranteed bandwidth: systems model. . . . . . . . . . . . . . . . . . . 204Figure 86 High Speed Gb interface: Logical Network view. . . . . . . . . . . . . . . . . . 205Figure 87 Gb over IP protocol Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206Figure 88 Wan Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207Figure 89 IP over Ethernet Encapsulation schema. . . . . . . . . . . . . . . . . . . . . . . . 208Figure 90 Flexible Gb configured with two SGSNs . . . . . . . . . . . . . . . . . . . . . . . . 210Figure 91 Example of pool area configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 211Figure 92 Example of PTPPKF Distribution During System Initialization . . . . . . . 220

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Figure 93 Example of PTPPKF distribution-Step 1 . . . . . . . . . . . . . . . . . . . . . . . 221Figure 94 Example of PTPPKF distribution - Step 2 . . . . . . . . . . . . . . . . . . . . . . 222Figure 95 Example of PTPPKF distribution in case of PCU unavailable . . . . . . . 223Figure 96 Example of PTPPKF distribution when a PCU is in Service . . . . . . . . 225Figure 97 Network Structure: Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229Figure 98 Mobility Management States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230Figure 99 Radio Resource States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235Figure 100 Packet Data Protocol States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236Figure 101 Coding of the 11 Bit Access Burst . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242Figure 102 One Phase Access on PCCCH channel . . . . . . . . . . . . . . . . . . . . . . . 243Figure 103 Two Phases Access on the CCCH . . . . . . . . . . . . . . . . . . . . . . . . . . . 244Figure 104 Packet Access Reject Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248Figure 105 TBF Establishment Initiated by the Network on the PCCCH channel . 250Figure 106 Behavior of T3182 Timer and N3102 Counter . . . . . . . . . . . . . . . . . . . 261Figure 107 Detection of anomalies during an Uplink TBF on the Network Side . . 262Figure 108 Release of an Uplink TBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264Figure 109 Release of the resources on Network Side during an UL TBF . . . . . . 264Figure 110 Control Procedure Executed by the Network during a Downlink TBF . 266Figure 111 Release of a Downlink TBF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267Figure 112 Suspend Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271Figure 113 Resume Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272Figure 114 Resume Procedure (The MS has changed the Routing Area) . . . . . . 273Figure 115 Enabled PFC Management without Multiple TBF . . . . . . . . . . . . . . . . 278Figure 116 Timeslot bandwidth portioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296Figure 117 Example of EDA Uplink TBF Multiplexing . . . . . . . . . . . . . . . . . . . . . . 296Figure 118 Timeslot scheduling Order Strategy. . . . . . . . . . . . . . . . . . . . . . . . . . . 297Figure 119 Example of Mobile Stations with two Uplink timeslots . . . . . . . . . . . . . 300Figure 120 Management of Adjacent Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315Figure 121 Network Assisted Cell Change algorithm. . . . . . . . . . . . . . . . . . . . . . . 322Figure 122 External NACC functionalities on BSC1 TDPC processor. . . . . . . . . . 325Figure 123 Network Controlled Cell Reselection Procedure . . . . . . . . . . . . . . . . . 334Figure 124 Combined GSM/UMTS Network Architecture . . . . . . . . . . . . . . . . . . . 339Figure 125 Allocation phase: Calculation of: Max_N_UL_TS . . . . . . . . . . . . . . . 359Figure 126 Overheating Management Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . 360Figure 127 OME and RRM Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361Figure 128 CS1 and CS2 Throughput Depending on C/I (dB). . . . . . . . . . . . . . . . 362Figure 129 Gross Throughput Depending on CS and C/I (dB) . . . . . . . . . . . . . . . 364Figure 130 BLER as Function of C/I (dB) for all GPRS Coding Schemes . . . . . . . 365Figure 131 Simulation Results for Family A (+MCS1) without IR . . . . . . . . . . . . . 368

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List of TablesTable 1 EGPRS Coding Schemes and their Modulation . . . . . . . . . . . . . . . . . . . 21Table 2 PTPPKF Managed Object. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Table 3 GPRS Coding Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Table 4 EGPRS Coding Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Table 5 EGPRS Coding Schemes and Families . . . . . . . . . . . . . . . . . . . . . . . . . 43Table 6 Coding of Stealing Bits for GPRS and EGPRS Radio Blocks. . . . . . . . . 45Table 7 Mobile Station Multislot Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Table 8 Conversion rule for Multislot classes frrom 30 to 33 . . . . . . . . . . . . . . . . 69Table 9 Types of cells in relation to the different types of Area . . . . . . . . . . . . . . 74Table 10 Example of Combinations of Trxmd and Trx Capability values . . . . . . . 82Table 11 PCU Functional Managed Object (FMO) . . . . . . . . . . . . . . . . . . . . . . . 128Table 12 Mapping of Services onto Abis Resources . . . . . . . . . . . . . . . . . . . . . . 140Table 13 Coding scheme and number of DL/UL transmitted bits . . . . . . . . . . . . 142Table 14 PCMG Functional Managed Object . . . . . . . . . . . . . . . . . . . . . . . . . . . 156Table 15 FRL Functional Managed Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157Table 16 NSVC Functional Managed Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160Table 17 Example of Setting of NSVC Values. . . . . . . . . . . . . . . . . . . . . . . . . . . 164Table 18 Example of NSVC Values Setting for both PCU-0 and PCU-1 . . . . . . . 166Table 19 Conditions enabling/disabling eFC feature . . . . . . . . . . . . . . . . . . . . . . 199Table 20 Correspondence between MM States and RR States . . . . . . . . . . . . . 236Table 21 Network Operation Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251Table 22 Attributes for DRX Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253Table 23 Puncturing Schemes to be used after a Coding Scheme Switch . . . . . 258Table 24 Service Precedence and Radio Priority Table . . . . . . . . . . . . . . . . . . . 291Table 25 Mapping between Radio Priority and Scheduling Priority Table . . . . . . 291Table 26 TGTPTPPKF Managed Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316Table 27 Attributes involved in the management of EGPRS/GPRS neighboring cells

317Table 28 Max_TS_Allocation_Table for an assigned scenario . . . . . . . . . . . . . . 357Table 29 GPRS Thresholds with RAENV set to LOWDIV/HIGHDIV . . . . . . . . . . 366Table 30 Thresholds to be used if Family A plus MCS1 are chosen . . . . . . . . . . 370Table 31 Thresholds to be used if Family B plus MCS1 are chosen . . . . . . . . . . 371Table 32 EDGE with Incremental Redundancy working and RAENV set to "LOWD-

IV" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371Table 33 EDGE with Incremental Redundancy not working and RAENV set to

"LOWDIV" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372Table 34 EDGE with Incremental Redundancy working and RAENV set to "HIGH-

DIV". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372Table 35 EDGE with Incremental Redundancy not working and RAENV set to

"HIGHDIV" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 372Table 36 Candidate Initial Coding Scheme for a GPRS TBF when the Historical Cod-

ing Scheme is related to an EGPRS TBF . . . . . . . . . . . . . . . . . . . . . . . 378Table 37 Candidate Initial Coding Scheme for an EGPRS TBF when the Historical

Coding Scheme is related to a GPRS TBF. . . . . . . . . . . . . . . . . . . . . . 378Table 38 GPRS/EGPRS Specific Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379Table 39 Attributes and related Managed Objects not specific for GPRS/EGPRS but

affected by PS services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392

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Table 40 GPRS/EGPRS Managed Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394Table 41 Unspecific GPRS/EGPRS Managed Objects affected by PS Services 394

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Reason for Update

Reason for UpdateIssue History

Issue 1 for Release BR9.0 (12/2006)

Issue Date Summary01 12/2006 New release BR9.0

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1 Introduction

1.1 Generalityg In current BR9.0 Release, the BSS system supports the BSC1 (BSC/72, BSC/120)

and eBSC Network Elements. In this manual BSC1 and eBSC are named BSC when there are not differences between them in term of supported features or func-tional behavior. When instead the Network Elements differ for hardware or software components or for specific supported features, this will be highlighted in the descrip-tion.

With the implementation of the second generation of mobile systems, due to the digital transmission mode they use, not only pure speech transmission, but also low rate data transmission and several supplementary services have been provided to final users.Nevertheless, since the request for data transmission supported by the mobile network is currently increasing respect to the voice services, growths in the area of data trans-mission are much higher than in the area of speech transmission.The HSCSD feature (High Speed Circuit Switched Data) increases the data transmis-sion rates in the GSM mobile network. It provides the possibility to match the ISDN transmission rate, by combining four timeslots of the TDMA frame.One disadvantage of HSCSD, however, is related to the circuit switched data transmis-sion it uses; in fact when the circuit switched connections are used the following limita-tion occurs: efficient resource management becomes difficult to reach.For this reason the HSCSD feature is essentially suited for those applications that involve high, but constant, transmission rates (for example the video telephony).The GPRS (General Packet Data Service) technology further increases the data rates. It provides the transmission of huge volumes of data in a very short time; on the other hand it ensures a better management of available resources, that means: increases the number of users; reduces the costs arising for individual users (volume-oriented fees).Using the GPRS technology it is possible to reach a maximum data throughput of about 150-170 kbit/s per each user.The incoming third generation of mobile networks, however, requires, for its forthcoming multimedia applications, much more bandwidth, at least 384 kbit/s. The Enhanced General Packet Data Service (EGPRS) represents the more recent GPRS upgrade and offers the opportunity to achieve those high data rates by preserving the most important GSM air interface features (like, for example, the 200 kHz channeling, TDMA access type, cell planning processes), by introducing a new modulation scheme (the 8 PSK instead of the GMSK). This means that the EGPRS services rely completely on the underlying GSM functionality.Due to its GSM/GPRS compatibility, EGPRS is the optimal packet data feature for established GSM operators. It provides an high protection for old investments and requires only small new investments. Looking at the fact that only a limited number of operators per country have been assigned UMTS licenses, EGPRS is also a good opportunity for those operators that require an evolutionary step for their mobile

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networks and provides the opportunity to offer advanced services foreseen for the third generation of mobile networks.For this reason it is expected that both UMTS and GPRS/EGPRS networks will coexist in the near future. The UMTS will serve mainly hotspots that require up to 2 Mbit/s data services per subscriber and the GPRS/EGPRS will be used to cover the rest of the area offering up to 384 kbit/s data services.

1.2 Structure of the ManualThis manual is the complete collection of GPRS/EGPRS features; each feature is described in detail together with the services that it provides to the final users. Therefore it allows the users to understand the main characteristics of the Packet Switched (PS) data services that support both GPRS and EGPRS technology.The complete list of all the Siemens technical documents describing the GPRS/EGPRS features is present in this manual. The documents are Feature Sheets and Change Requests. A Feature Sheet describes in detail in which way the related feature has been implemented in the BSS system. A Change Request provides a short indication of what is necessary to modify or to implement in the BSS system due to new customer require-ments or internal development systems improvements. For each Feature Sheet or Change Request, this manual provides the following information: Its internal code (number) and title; A short description of the feature; The release of the system in which the described feature will be implemented.Finally four different tables are contained in the last part of the manual: In the first table all the parameters, of GPRS/EGPRS only competence, which have

been described in the manual are collected in their alphabetical order. Each param-eter is related to the link pointing to the section in the manual in which the parameter is described and also to the link pointing to the title of the eventual Feature Sheets (or Change Requests) that introduce or describe the parameter in the SBS system. In this way an user searching technical details or more information can easily find in the manual the location where the parameter is described and also which are the other documents that provide additional information.

In the second table all the parameters, not of GPRS/EGPRS competence but that are however related to this technology, which have been described in the manual are collected in their alphabetical order. Each parameter is related to the link pointing to the section in the manual in which the parameter is described and also to the link pointing to the title of the eventual Feature Sheets (or Change Requests) that introduce or describe the parameter in the SBS system starting from the SBS BR 5.5. In this way an user searching technical details or more information can easily find in the manual the location where the parameter is described and also which are the other documents that provide additional information.

In the third table all the Managed Objects, of GPRS/EGPRS only competence, which have been described in the manual are collected in their alphabetical order. Each Managed Object is related to the link pointing to the title of the eventual Feature Sheets (or Change Requests) that introduce or describe it within the SBS system. In this way an user searching technical details or more information can easily find in the manual the location where the parameter is described and also which are the other documents that provide additional information.

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In the fourth table all the Managed Objects which are not specific for the GPRS tech-nology but however related to the provided services are listed in their alphabetical order. Each Managed Object is related to the link pointing to the section in the manual in which it is described and also to the link pointing to the title of the eventual Feature Sheets (or Change Requests) that introduce or describe the parameter in the SBS system starting from the SBS BR 5.5. In this way an user searching tech-nical details or more information can easily find in the manual the location where the parameter is described and also which are the other documents that provide addi-tional information.

The manual is structured in the following chapters: 1 Introduction: This chapter explains the purpose of the manual and its structure; 2 GPRS/EGPRS Overview: This chapter introduces the system, the network archi-

tecture, the protocol stack and the data flow across the several involved network entities.

3 Radio Interface Description: This chapter describes the radio interface: the new logical channels, their mapping on the corresponding physical channels and the rules that allow the sharing on the same physical channel among several mobile stations and the assignment of more physical channels to the same mobile station.

4 Radio Resource Management: This chapter introduces the Radio Resource Man-agement in the context of the GPRS/EGPRS system. It is described in which way the user can configure the resources of the cell to allow the management of both circuit switched (CS) and packet switched (PS) services; some examples are also introduced to clarify better in which way the related resources (physical or logical) can be handled.

5 Hardware and Software Architecture: This chapter describes the hardware archi-tecture of the GPRS/EGPRS system pointing to the new resources in the BSC requested by the new technology.

6 Gb Interface: This chapter describes to the Gb interface. It connects the BSC to the core network. The frame relay protocol, which characterizes the Gb interface, is described together with the physical layer, the permanent virtual connection and some examples of configuration. Also some procedures are detailed.

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7 Load Control for Packet Switched Services: This chapter describes the load control mechanism, that is used to distribute in an optimized way the GPRS/EGPRS traffic among the internal resources of the BSC.

8 GPRS/EGPRS Procedures: This chapter describes in details the supported GPRS/EGPRS procedures.

9 GPRS/EGPRS Functionalities: This chapter details the main GPRS/EGPRS func-tionalities, for example the Cell Selection/Reselection, the management of neigh-bouring cells, etc.

10 Managed Objects and Attributes: This chapter contains the tables with the list of all the Managed Objects and related attributes that have been described or referred in the manual.

11 Abbreviations: This chapter contains the list of the abbreviations adopted or referred in the manual.

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GPRS/EGPRS Global Description GPRS/EGPRS Overview

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2 GPRS/EGPRS OverviewThe General Packet Radio Service (GPRS) and the Enhanced General Packet Radio Service (EGPRS) technology allow the packet switched data transmission on the frame-work provided by the GSM mobile network.The GPRS/EGPRS is supported by the BSC1 (BSC/72, BSC/120) and the eBSC, referred in this chapter as BSC. In case a feature depends on a specific BSC type, it will be highlighted in the description.g EDGE (Enhanced Data rates for GSM Evolution) applies both to the circuit switched

(CS) and to the packet switched (PS) services. EDGE is mainly a characteristic of the Air Interface, including a new modulation (8PSK, besides the already used GMSK modulation. See for more details the chapter:2.1, GPRS and EGPRS Mod-ulation Principles.The word EGPRS (Enhanced GPRS) applies only to the packet switched (PS) ser-vices. Whenever in this document the word EGPRS is adopted, EDGE is referred and it is applied to the packet switched (PS) services. That means, substantially, the coding of the radio blocks using a specific set of modulation and coding schemes (MCS1, .., MCS9), and using new specific RLC/MAC control messages or new specific information elements in the GPRS RLC/MAC control messages. In the previous BSS BR 7.0 release, EDGE is applied only to packet services. However, the generic term EDGE is used in the Operation&Maintenance attributes that could be used to define the support of EDGE also for the circuit switched (CS) service. In any case in this manual, the world EDGE means EGPRS and viceversa.

When the GPRS/EGPRS technology is not configured, the GSM mobile network runs in circuit switched connection mode, for example it gives to the customer the exclusive use of a certain amount of bandwidth for the duration of the requirement. The connection is set up on demand and released when the caller breaks the connection. Circuit switched connections (CS) are what is provided by the GSM architecture for speech and data ser-vices. Data transmission with bandwidth larger than 9.6 kbit/s (or larger than 14.4 kbit/s, if this higher data rate is enabled) is reached with the support of more radio channels to a given user, by the HSCSD feature. Nevertheless, when a circuit switched connection is established and the user does not transmit further information, which is typical of data transmission, the specific resources are wasted because they are not available for other users waiting the availability of the service. In other words, it means that the circuit switched connections do not provide an optimized support for data traffic.In order to improve and optimize the use of both the network and radio resources, for both GPRS and EGPRS technology the packet switched (PS) technique has been implemented for supporting efficiently both data and signalling transfer.New GPRS/EGPRS radio channels are defined, and the allocation of these channels is flexible as follow: from 1 to 8 radio interface timeslots can be allocated for TDMA frame, for each trans-

ceiver of the cell; timeslots are shared by the active users (the same timeslot can be assigned to dif-

ferent users at the same time); radio interface resources can be shared dynamically between speech services

(circuit switched services) and data services (packet switched services) as a function of service load and also on the basis of different users needs;

uplink and downlink resources are allocated separately.

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Applications that take advantage of GPRS/EGPRS services have the following charac-teristics: Intermittent, non-periodic (i.e., bursts) data transmission; Frequent transmission of small volumes of data; Not frequent transmission of large volumes of data.

2.1 GPRS and EGPRS Modulation PrinciplesThe GPRS technology is an evolution of the existing GSM technology and it uses the same GMSK Gaussian Minimum Shift Keying) modulation scheme. The GMSK digital modulation format relies on shifting the carrier 180 in phase to produce a binary mo-dulation scheme capable of delivering 1 bit/symbol as represented in the Figure 1.

Figure 1 Basic GMSK Constellation of Signal Vectors

The GPRS uses four different channel coding schemes (see the chapter: "3.2.1 GPRS Channel Coding") to provide different levels of protection to the packets on the air inter-face.This modulation scheme, within 200 KHz bandwidth, provides a good spectral perfor-mance and an adequate data rates for GSM voice applications, however it cannot supply fast data services since it only transmits 1 bit/symbol.The EDGE technology uses the same bandwidth allocated for GSM voice and GPRS data services, but delivers a higher capacity and fast data services to the mobile network by using a new modulation scheme called 8 PSK (8-level Phase Shift Keying). With this 8PSK modulation, there are eight distinct phase changes that the decoder looks for the conversion into binary data. Each phase represents a symbol and carries three bits of information as reported in next Figure 2.

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Figure 2 Basic 8 PSK Constellation of Signal Vectors

As a consequence, the EDGEs 8 level-shift keying modulation scheme allows a radio throughput increase of almost 3 times the radio throughput of the GPRS with the same number of timeslots with big advantages for the final users. In the following table the comparison of the physical layer parameters is depicted.

With the classical 8 PSK modulation scheme, it is possible during symbol changes for the signal trajectory to pass through the origin (I/Q value 0,0), which causes both a very high Peak to Average Value (PTA) and a high dynamic range of the signal. To avoid this possibility, EDGE uses a 3pi/8-shifted 8PSK approach, by which with every phase tran-sition, the symbols rotate by 3pi/8 causing a shift of the I/Q constellation relative to its previous starting position.Nine coding schemes (from MCS1 to MCS9, as described in the chapter: "3.2.2 EGPRS Channel Coding") using both the GMSK and the 8 PSK modulations are introduced and a specific link adaptation algorithm allows the automatic switching between coding schemes, based on the radio environment condition. The table below shows which EDGE coding schemes are GMSK modulated and which instead are 8 PSK modulated.

GSM EDGEModulation GMSK, 1bit/sym 8 PSK, 3 bit/symSymbol Rate 270833 kbit/s 270833 kbit/sPayload per Burst 114 bit 348 bitGross Rate per Time Slot

22.8 kbit/s 69.6 kbit/s

GMSK modulated 8 PSK modulatedMCS1 MCS5MCS2 MCS6MCS3 MCS7

Table 1 EGPRS Coding Schemes and their Modulation

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2.2 Network ArchitectureThe packet data mobile network establishes a logical connection between the users but does not guarantee an immediate access to the transmission network: when more users ask the access to the transmission resources at the same time, the network has to schedule the access keeping some of them in a wait queue for avoiding traffic conges-tion.As shown in Figure 3, the GPRS/EGPRS network is put on the top of the GSM existing one but without substitute it. In fact the network architecture grants that speech and data transmission with circuit switched connections (CS) are controlled by the MSC (through the A interface).

Figure 3 GPRS/EGPRS Network Architecture.

For providing the Packet Switched (PS) services two network nodes in the GSM core network have been introduced: Serving GPRS Support Node (SGSN): the SGSN keeps track of the individual

Mobile Station location and performs security functions and access control. It is at the same hierarchical level as the MSC and it can be connected to the Base Station System (BSS) via a Frame Relay network. It is also possible to connect the SGSN and the BSS via nailed-up connections (NUCs) or through point-to-point connec-tions.

MCS4 MCS8MCS9

GMSK modulated 8 PSK modulated

Table 1 EGPRS Coding Schemes and their Modulation

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g The SISGNREL99 attribute is broadcasted in the cell, in order to inform the Mobile Stations about the specification Release implementation in the SGSN.

The SGSN and the BSC are connected by the Gb interface. It specifies the data flow and the requested protocols (see the Chapter: "6 Gb Interface") and it consists of connections which carry both data and signalling simultaneously, using the Frame Relay protocol. Besides the Gb interface is standard and it guarantees multi-vendor capabilities.

Gateway GPRS Support Node (GGSN): this node GGSN provides: interworking with external packet switched (PS) networks; management of IP addresses.The GGSN could be connected to the SGSN via an IP-based GPRS/EGPRS backbone network; in this way these two entities can also reside on the same physical node.

The interface between the SGSN and the GGSN is the Gn Interface.Two GGSN nodes can be interconnected through Gp Interface.Besides the Home Location Register (HLR) Database has to be upgraded with GPRS/EGPRS subscriber information, and optionally the MSC/VLR can be enhanced for a more efficient coordination of GPRS and non-GPRS services and functionalities like for example the following: paging of circuit switched calls through the SGSN; combined GPRS and non-GPRS location updates.To allow the co-ordination of activities between the MSC and the SGSN, the Gs interface must be supported as represented in above Figure 3.The security management functions for the GPRS/EGPRS technology do not differ for those implemented for the GSM system: the SGSN performs authentication and cipher setting procedures based on the same algorithms, keys, and criteria adopted in GSM; the only difference is that GPRS/EGPRS networks require an enhanced ciphering algo-rithm optimized for the packet data transmission.In order to access to the packet switched (PS) services, a Mobile Station (a specific hardware and software is needed for being able to provide GPRS services) first makes its presence known to the SGSN by performing a GPRS attach procedure. It is described in detail in the chapter: "8.3.2.1 Attach Function". This operation establishes a logical link between the Mobile Station and the SGSN, and it provides the following functions: paging via the SGSN; notification of incoming GPRS/EGPRS specific data; SMS services over GPRS services;So at the end of a successful GPRS attach procedure, the SGSN establishes with the mobile station a mobility management session, containing information pertaining to, for example, mobility and security etc.In order to send and receive packet switched (PS) data, the Mobile Station first activates the packet data address that it wants to use. In this way the Mobile Station will be re-cognized by the corresponding GGSN and then the interworking with external data networks can begin. During this procedure, which is called PDP context activation (Packet Data Protocol context activation), the SGSN establishes a PDP context with the related GGSN as it is described in the chapter: "8.7 Activation and Deactivation of a PDP Context" This context is used for routing purposes when the user: will send data to the external data network;

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will receive data from the external data network.At the end of the successful execution of the attach and of the PDP context activation procedures, the Mobile Station can start the transmission or reception of data.For the purpose, the Mobile Station shall establish a physical connection with the network; this physical connection is called Temporary Block Flow. The Temporary Block Flow allows unidirectional transfer of data through the allocated radio resources.The User data is transferred transparently between the Mobile Station and the Core network with a method known as encapsulation and tunnelling: data packets are com-pleted with GPRS/EGPRS specific protocol information and transferred between the Mobile Station and the GGSN of competence. This transparent transfer method lessens the requirement for the GPRS PLMN to interpret external data protocols, and it enables an easy introduction of additional interworking protocols in the future. User data can be compressed and protected with retransmission protocols, to get a consistent, efficient and reliable data transmission.

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2.3 GPRS/EGPRS supported by satellite linksThe transmission of data requested by GPRS/EGPRS services is supported also by means of satellite links. This transmission mode is often used for providing the services via particular network configurations to users residing for example in wide or very large areas with minimum additional infrastructure cost.In next chapter a description of Abis interface supported by satellite links is provided.

2.3.1 Abis InterfaceAbis interface is supported over satellite links. This transmission mode is the most common implementation and it is often used to extend the GSM and GPRS/EGPRS services to new locations with minimal infrastructure costs. For the reason that GSM traffic grows also at remote sites, additional BTSs or a BSC may be deployed to support higher traffic loads and/or a larger geographical area.The satellite Abis configuration has the advantage that a minimal expense is requested for deploying the service. An existing MSC and BSC can be used, which could possibly support satellite connections to several remote locations.The main disadvantage of the satellite Abis configuration is that the remote locations relies heavily on the equipment located at the hub side so hand-offs and also eventual subscriber to subscriber calls must go over satellite link increasing load and traffic.The configurations attributes together with the related commands requested for the Abis over satellite links are out of the scope of this manual. They are described in the manual: CML:BSC.Besides the value of the attribute: nRLCMAX (this attribute determines the number of RLC data blocks before Ack/Nack block is requested) of PCU Managed Object has been changed from 20 to 15 for reducing the problem related to Abis satellites delay. This attribute is not configurable in the BSS system.When BSS receives a message: "Channel Request" from a Mobile Station, a TCH channel in case of direct assignment) is allocated by BSC. After this allocation an acti-vation phase is triggered by the BSC sending the message: Channel Activation to the BTS and waiting the message: Channel Activation acknowledge.Only after successful completion of the activation phase the message: "Immediate Assignment" is sent back to the Mobile Station. This procedures causes a double Mobile Station access in case of Abis on satellite link.For avoiding MS double access, in current release and only for Abis over satellite link, a message: "Immediate assignment" is sent to the Mobile Station just after sending the message: "Channel Activation" to the BTS. In this way BSC manages the message: "Channel Activation Nack" from the BTS without sending the message: "Immediate Assignment reject". This modification increases the success rate for the TCH channels assignment in high traffic conditions from 50% up to 90%.To perform TD admission control a specific attribute has been related to CPCU object. This attribute defines the minimum transfer delay value that can be supported by the BSS system. Packet flow contexts that require a transfer delay smaller than the attribute, are not accepted. See the CML:eBSC for more details about the attributes related to the CPCU object.

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GPRS/EGPRS Overview

2.4 GPRS/EGPRS Protocol StackGPRS and EGPRS technology is supported at every level of OSI stack by a set of pro-tocols that are represented in Figure 4 together with the corresponding interfaces starting from the air-interface (Um) up to the core Network (Gn Interface between the SGSN and the GGSN).

Figure 4 Protocol Stack for Data Transmission in GPRS/EGPRS Network

The different layers for the Um, Abis, Gb, Gn and Gi interfaces provide the following functions: GSM RF: the GSM RF is the protocol specified for the Um and the Abis interfaces.

It supports the physical radio channel used to transfer packet data. MAC: The Media Access Control layer is the protocol specified for the Um and the

Abis interfaces.It provides the access to the physical radio resources. It is responsi-ble for the physical allocation of the packet data channels (PDCHs);

RLC: the Radio Link Control layer is the protocol specified for the Um and the Abis interfaces.It provides a reliable link over the air interface that fits the block structure of the physical channel; therefore its main task is the segmentation and reassem-bling of the LLC frames transmitted between the BSS and the SGSN. In addition it performs a sub-multiplexing to support more than one Mobile Station by one physical channel. It performs also the channel combining to provide up to eight physical channels to one Mobile Station;

LLC: the Logical Link Control layer provides a logical connection between the Mobile Station and the SGSN even if no physical connection is established. The physical connection is set up by the RLC/MAC layer when there is data to transmit;

BSSGP: the BSSGP protocol is specified for the Gb interface and it is used to transfer LLC frames together with related information between the SGSN and the BSC. Such information include QoS (Quality of Service) and routing information;

SNDCP: the Sub Network Dependent Convergence Protocol is the protocol speci-fied for the logical interface between the Mobile Station and the SGSN. It performs the following tasks: Encryption, Compression, Segmentation, Reassembling, Multi-plexing/demultiplexing of signalling information and data packets.The encryption

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function grants the best security for the data transmission whereas the compression and the segmentation are performed to limit the amount of data transferred by the LLC layer;

GTP: The GPRS Tunnelling Protocol is specified for the Gn interface. Its main task is the encapsulation/de-encapsulation function. The different kinds of data packets are encapsulated in IP packets since IP is the GPRS/EGPRS internal network pro-tocol. The encapsulated data packets are then transferred between the GSN nodes;

IP/X.25: The network layer represents the network protocol that supports the infor-mation transferred over the GPRS/EGPRS network starting from the Mobile Station up to the GGSN. Depending on the supported network protocol (IP, X.25, CLNP), there are several types of network layers;

Application: The higher layers (for example the Application Layer) are outside the scope of the GPRS/EGPRS, because they are not dependent from the underlying network.

2.5 Data FlowThis chapter describes in which way the data are transmitted from the core network (SGSN) up to the Mobile Station, and vice versa.The figures Figure 5 and Figure 6 represent in which way the different protocols layers manage the data flow: The Figure 5 represents the data flow in case of GPRS and EGPRS when the

MSC1..MSC6 coding schemes are used; The Figure 6 represents the data flow in case of EGPRS when the MSC7..MSC9

coding schemes are used (see description below);

Figure 5 Data Flow across Protocol Layers in case of GPRS/ EGPRS(MSC1...MSC6)

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Figure 6 Data Flow across Protocol Layers in case of EGPRS(MSC7..MSC9)It is supposed that an IP data packet has to be sent from an external data network to a mobile subscriber.

g Precondition is that the Mobile Station has already executed the attach procedure and it has already activated the PDP context towards the involved data network.

The following steps are performed:1. the Internet Service provider sends the IP data packet unit to the GPRS/EGPRS

network, using the IP address which has been assigned to the Mobile Station during the PDP context activation procedure;

2. the GGSN searches for the relevant PDP context and forwards the data unit towards the right SGSN. The original IP data unit is encapsulated in a new one (using the GTP protocol), and the new IP address is the IP address of the SGSN;

3. the SGSN decapsulates the IP data packet and (by means of the SNDCP protocol) it subdivides the data packet in a certain number of LLC frames (data is also encrypted and compressed).

4. when the SGSN knows the location of the Mobile Station (for example the cell where the Mobile Station is camped on), these LLC frames are sent to the right BSC, across the Gb interface. As in the GSM system, the paging procedure is used to localize the subscriber.

5. The LLC frames have a variable length; since they have to be sent on the radio inter-face, which has a limited capacity, the LLC frames are segmented in a certain number of RLC/MAC blocks; these blocks have a well defined length (according to the used coding scheme);

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6. The RLC/MAC blocks are then sent through the Abis interface, to the right BTS;g RLC/MAC blocks are sent across the Abis interface, by means of PCU frames.

Two types of PCU frames exists: standard PCU frames: they allow the transmission of a restricted number

of bits every 20 msec and so they support only CS1 and CS2 GPRS coding schemes;

concatenated PCU frames: they support not only CS1 and CS2 GPRS coding schemes, but also CS3 and CS4, and all the EGPRS coding schemes (MSC1..MSC9).

More details are described in chapter: "5.3 PCU Frames and Dynamic Allocation on the Abis Interface".

7. the BTS executes the following operations for the received RLC/MAC blocks: block coding; convolutional coding; puncturing; interleaving.Regarding these operations, it is important to make a distinction among the following different cases: when GPRS coding schemes are used, a single RLC/MAC block contains one

Information Field only; the BTS executes the described operations on it; after these operations, each received RLC/MAC block reaches, independently from the applied coding scheme, a fixed length of 456 bits;

when EGPRS GMSK coding schemes are used (i.e., from MCS1 to MCS4), a single contains one Information Field only; the BTS executes the described operations on it; after these operations, each received RLC/MAC block reaches, independently from the applied coding scheme, a fixed length of 1368 bits;

when EGPRS MCS5 and MCS6 coding schemes are used, a single RLC/MAC block contains one Information Field only; the BTS executes the described oper-ations on it; after these operations, each received RLC/MAC block reaches, independently from the applied coding scheme, a fixed length of 1392 bits;

when EGPRS MCS7, MCS8 and MCS9 coding schemes are used, a single RLC/MAC block contains two Information Fields; the BTS executes the described operations on the RLC/MAC block; after these operations, the RLC/MAC block reaches, independently from the applied coding scheme, a fixed length of 1392 bits;

8. The block that is obtained after different coding procedures is called Radio Block. Each Radio Block is then sent on the radio interface by means of 4 Normal Bursts, in fact each Normal Burst can transmit: up to 114 bits in cases of GPRS; up to 114 bits in cases of EGPRS when GMSK modulation is used; up to 348 bits in cases of EGPRS when 8PSK modulation is used.

The figure Figure 7 shows the data flow between the SGSN and the Mobile Station in the downlink direction through the Gb, Abis and Um interfaces (in the uplink direction the same data flow is transmitted but in the opposite order).

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GPRS/EGPRS Overview

Figure 7 Data Flow from the SGSN up to the Mobile Station

For more clearness the following definitions are used: RLC/MAC block: a RLC/MAC block is a block generated in the BSC (by the

RLC/MAC layer) starting from the LLC-PDU; then this block is sent using PCU frames to the BTS that than it applies the right coding;

Radio Block: a Radio Block is a RLC/MAC block that is generated after the BTS has applied the block coding (i.e., it is a RLC/MAC block plus some coding bits).

g After block coding, the BTS will apply the convolutional coding and both puncturing and interleaving procedures; after these operations the interested block will reach a fixed length of 456 or 1392 bits, and it is still called Radio Block.

2.6 RLC/MAC Block and Radio Block StructuresDifferent RLC/MAC block (and as a consequence different Radio Block) structures for data transfer and control message transfer purposes are defined.The RLC/MAC block structure for data transfer is different between GPRS and EGPRS, whereas the same RLC/MAC Block structure is used for the management of control messages.g All the different RLC/MAC block types, after the coding, are always carried by four

Normal Bursts on the Um radio interface.

2.6.1 RLC/MAC and Radio Block Structures: Data TransferAs it has been described, two different RLC/MAC Block structures are defined for GPRS and EGPRS data transfer.

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2.6.1.1 RLC/MAC Block and Radio Block Structures for GPRS Data TransferA RLC/MAC block for data transfer supported by the GPRS technology consists of one MAC Header, one RLC Header and one RLC Data Block as represented in next Figure 8. The MAC Header contains control fields with different values for the uplink and

downlink directions and it has a constant length of 8 bits. The RLC Header contains control fields with different values for the uplink and

downlink directions and it has a variable length. The RLC Data Block field contains octets from one or more LLC PDUs.

Figure 8 RLC/MAC blocks structure for Data Transfer

The RLC/MAC block is sent to the BTS, that will apply a block coding for the error detec-tion, adding to the RLC Data Block field the Block Check Sequence (BCS) field. At the end of the operation the Radio Block is generated, as represented in next Figure 9. This Radio Block, after convolutional coding, puncturing and interleaving, is then transmitted on the Um air interface and carried by four Normal Bursts.

Figure 9 Radio Block structure for Data Transfer on the Um Interface

2.6.1.2 RLC/MAC Block and Radio Block Structure for EGPRS Data TransferA RLC/MAC block for data transfer supported by the EGPRS technology consists of one RLC/MAC Header, and one or two RLC Data Blocks. the RLC/MAC Header contains control fields with different values for the uplink and

downlink directions. It also has a variable length; the RLC Data Block field contains octets from one or more LLC PDUs;The EGPRS

coding schemes from MCS1 to MCS6 use a RLC/MAC block constituted by only one RLC Data Block field only (as represented in Figure 10), whereas the coding schemes from MCS7 to MCS9 use a RLC/MAC block constituted by two RLC Data Block fields to reach a more high data rate as represented in Figure 11.

Figure 10 RLC/MAC Block structure with one RLC Data Block field

MAC Header RLC Header

RLC Data

MAC Header RLC Header RLC Data BCS

RLC/MAC Header

RLC Data Block

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Figure 11 RLC/MAC Block structure with two RLC Data block fields

The RLC/MAC block is sent to the BTS, that will apply a block coding for the error detec-tion. At the end of the operation the Radio Block is generated. (see Figure 12 in case only one RLC Data Block is inserted and Figure 13 in case two RLC Data Blocks are inserted). Besides two different block coding are applied for the error detection: the Block Check Sequence (BCS) is used for the error detection of the data part. the Header Check Sequence (HCS) is used for the error detection of the header

part.The RLC/MAC Header does not interact from the RLC Data Block and it has its own check sequence.In cases of RLC/MAC blocks constituted by two RLC Data Block fields , each field has its own block check sequence whereas the RLC/MAC Header is common for both the fields.At the end of the checks and after convolutional coding, puncturing and interleaving, the RLC/MAC Block structure represented in Figure 13 is transmitted on the Um Air Inter-face and carried by four Normal Bursts.

Figure 12 Radio Block for Data Transfer with one RLC Data Block field

Figure 13 Radio Block for Data Transfer with two RLC Data Block field

RLC/MAC Header

RLC Data Block RLC Data Block

BCSRLC/MAC

Header HCS RLC Data Block

BCSRLC/MAC

Header BCSHCS RLC Data Block RLC Data Block

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2.6.2 RLC/MAC Block Structure: Control SignallingThe same RLC/MAC Block for transferring a control message (for example a signal-ling message) is supported by the GPRS and the EGPRS technology. It consists of one MAC header and one RLC/MAC Control Message as represented in the Figure 14. The Header and the RLC?MAC Control Message have the following structure: the MAC Header contains control fields with different values for the uplink and

downlink directions and it has a constant length of 8 bits. the RLC/MAC Control Message field contains one RLC/MAC control message;It is always carried by four normal bursts.

Figure 14 RLC/MAC Block Structure for Control Messages

The RLC/MAC block is sent to the BTS that will apply a block coding for the error detec-tion by the addition of a Block Check Sequence (BCS) field. At the end of the operation the Radio Block is generated as represented in Figure 15. After convolutional coding, puncturing and interleaving the Radio Block is then transmitted on the Um Air interface and carried by four Normal Bursts.

Figure 15 Radio Block for Control Messages (signalling)The following control messages can be transmitted in the downlink direction within a RLC/MAC signalling Block Structure: Packet Paging Request: This message is sent by the network to trigger the channel

access by up to four Mobile Stations for a connection s establishment. Packet Downlink Assignment: This message is sent from the network to assign

resources to the Mobile Station in the downlink direction. Packet Uplink Ack/Nack: This message is sent from the network to the Mobile

Station for the acknowledgement of data blocks sent in the uplink direction. Packet Power Control/Timing Advance: This message is sent by the network to the

Mobile Station for the reconfiguration of either the timing advance (TA) and/or the power control parameters.

Packet Access Reject: This message is sent by the network to the Mobile Station to indicate that the network has rejected its access request.

The following control messages can be transmitted in the uplink direction within a RLC/MAC signalling Block Structure: Packet Downlink Ack/Nack:This message is sent from the Mobile Station to the

network for the acknowledgement of data blocks sent in the downlink direction. Packet Control Acknowledgment: This message is sent from the Mobile Station to

the network for the acknowledge of control blocks sent in the downlink direction;g The Packet Control Acknowledgment message is not formatted as a single

RLC/MAC block, but as four Access Bursts.

MAC Header RLC/MAC Control Message

MAC Heade

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