GPRS Planning Guide

8/6/2019 GPRS Planning Guide

1/163

GPRS PLANNING GUIDE

GPRS PLANNING GUIDE


2/163

GPRS PLANNING GUIDE

TABLE OF CONTENTS

TABLE OF CONTENTS..............................................................................................................................2

1. DOCUMENT RELEASE PLAN...............................................................................................................5

2. INTRODUCTION......................................................................................................................................6

3. ACRONYMS AND TERMS .....................................................................................................................7

4. REFERENCES.........................................................................................................................................16

5. GPRS FEATURES SUPPORTED..........................................................................................................23

5.1.BSS.......................................................................................................................................................23

5.2.GSN COMPLEX.......................................................................................................................................24

5.3.OMC-G.................................................................................................................................................25

6. GPRS INTERFACES...............................................................................................................................26

7. MOTOROLA GSM / GPRS NETWORK ARCHITECTURE............................................................27

8. MOTOROLA PRODUCTS AND INTERFACES SUPPORTED.......................................................28

8.1.EXISTING BTS PRODUCTS.........................................................................................................................28

8.2.NEW PRODUCTS.......................................................................................................................................28

8.3.INTERFACES SUPPORTED.............................................................................................................................29

9. THE PLANNING PROCESS..................................................................................................................30

10. GPRS NETWORK TRAFFIC ESTIMATION AND KEY CONCEPTS.........................................32

10.1.DYNAMICTIMESLOTMODESWITCHING........................................................................................................36

10.2.BACKGROUNDAND DISCUSSION................................................................................................................36

10.3.CARRIERTIMESLOTALLOCATIONEXAMPLES.................................................................................................39

10.3.1.Example A...................................................................................................................................40

10.3.2.Example B...................................................................................................................................40

10.3.3.Example C..................................................................................................................................4110.3.4.Example D..................................................................................................................................41

10.3.5.Example E ..................................................................................................................................42

10.4.BSS TIMESLOT ALLOCATIONMETHODS.....................................................................................................43

10.5.RECOMMENDATION..................................................................................................................................48

11. AIR INTERFACE PLANNING PROCESS.........................................................................................51

11.1.AIRINTERFACEPLANNINGINPUTS..............................................................................................................5111.2.AIRINTERFACE THROUGHPUT...................................................................................................................55

12. BSS PLANNING ....................................................................................................................................65

12.1.PCU-TO-SGSN INTERFACE PLANNING....................................................................................................66

12.2.BSS UPGRADE PROVISIONING RULES..................................................................................................67

12.3.PCU PROVISIONING RULES.....................................................................................................................68

12.4.LINKPROVISIONING RULES......................................................................................................................77

12.4.1.BTS-BSC E1 links (Abis)............................................................................................................79

12.4.1.1.Traffic (GPRS timeslots)..........................................................................................................79


3/163

GPRS PLANNING GUIDE

12.4.1.2.Signalling (RSL)......................................................................................................................79

12.4.2.BSC-PCU....................................................................................................................................83

12.4.2.1.Traffic (GDS TRAU)................................................................................................................83

12.4.2.2.Signaling (GDS LAPD GSL)...................................................................................................83

12.4.3.PCU-SGSN.................................................................................................................................85

12.4.3.1.Traffic and Signaling (Gb)......................................................................................................85

12.4.3.2.Frame Relay Parameter Values..............................................................................................8712.5.GPRS CONTROL CHANNNEL RF PROVISIONING.........................................................................................90

12.6. LCF GPROCII PROVISIONINGFORGPRS SIGNALING.............................................................................95

12.7.FEATURE COMPATIBILITY.........................................................................................................................98

12.7.1.alarms consolidation..................................................................................................................98

12.7.2.Concentration at BTS.................................................................................................................98

12.7.3.Circuit error rate monitor..........................................................................................................98

12.7.4.Circuit Switched (Voice or Data) calls......................................................................................98

12.7.5.Concentric Cells.........................................................................................................................99

12.7.6.Congestion Relief........................................................................................................................99

12.7.7.Cell Resource manager (CRM) Dyanmic Recongfiguration......................................................9912.7.8.Directed Retry............................................................................................................................99

12.7.9.Emergency Call Preemption.......................................................................................................99

12.7.10.Extended Range Cells.............................................................................................................100

12.7.11.Frequency hopping & Re-definition.......................................................................................10012.7.12.Global Reset...........................................................................................................................100

12.7.13.Integrated M-Cell HDSL Interface.........................................................................................100

12.7.14.Multiband handovers..............................................................................................................100

12.7.15.Over the air flow control for circuit switched mobiles...........................................................10012.7.16.RTF path fault Containment...................................................................................................101

12.7.17.SMS Cell Broadcast................................................................................................................101

13. GSN COMPLEX PLANNING............................................................................................................102

13.1.1.CommHub ................................................................................................................................104

13.1.2.ISS Module................................................................................................................................104

13.1.3.GSN Shelf..................................................................................................................................10513.1.4.GGSN Module..........................................................................................................................105

13.1.5.SGSN Module...........................................................................................................................10513.1.6.C7 Module................................................................................................................................106

13.1.7.Management Module................................................................................................................106

13.2.GSN PLANNING INPUTS........................................................................................................................107

13.3.GSN PLANNING PROCESS.....................................................................................................................111

13.4.GSN MAXIMUM CONFIGURATIONS.........................................................................................................121

13.5.LINKPROVISIONING..............................................................................................................................12313.5.1.Ga Interface.............................................................................................................................123

13.5.2.Gb Interface..............................................................................................................................123

13.5.3.Gi Interface...............................................................................................................................124

13.5.4.Gn Interface..............................................................................................................................124

13.5.5.Gr Interface..............................................................................................................................124

14. GPRS NETWORK STATISTICS FOR NETWORK RE-PLANNING..........................................125

14.1.BSS STATISTICS..................................................................................................................................125

14.2.GSN COMPLEX STATISTICS...................................................................................................................134

14.2.1.SGSN.........................................................................................................................................134

14.2.2.GGSN........................................................................................................................................141

15. BSS SYSTEM CONFIGURATIONS..................................................................................................144

15.1.MINIMUM SYSTEM................................................................................................................................144

15.2.SYSTEM INCREMENTS............................................................................................................................144


4/163

GPRS PLANNING GUIDE

15.3.MAXIMUM SYSTEM...............................................................................................................................144

15.4.E1 INTERFACE PROVISIONING.................................................................................................................145

15.5.REDUNDANCY PLANNING.......................................................................................................................146

16. GSN COMPLEX SYSTEM CONFIGURATIONS..........................................................................150

16.1.MINIMUM REFERENCE SYSTEM...............................................................................................................150

16.2.SYSTEM

INCREMENTS

............................................................................................................................15016.3.MAXIMUM REFERENCE SYSTEM..............................................................................................................150

16.4.LAN / WAN PROVISIONING...............................................................................................................150

16.4.1.GSN Complex Networking options...........................................................................................150

16.4.2.Ethernet Interface Provisioning...............................................................................................150

16.4.3.E1 Interface Provisioning.........................................................................................................151

16.4.4.Frame Relay Interworking.......................................................................................................151

16.5.SUPPORTED REDUNDANCY......................................................................................................................15116.5.1.Communications Cabinet.........................................................................................................151

16.5.2.GSN Cabinet.............................................................................................................................152

17. PLANNING EXAMPLES....................................................................................................................153

17.1.PCU PLANNINGEXAMPLE......................................................................................................................153

BSC..........................................................................................................................................................153

17.2.GSN COMPLEX PLANNING EXAMPLE......................................................................................................159

18. RECOMMENDED PLANNING GUIDELINES...............................................................................163


5/163

GPRS PLANNING GUIDE

1. DOCUMENT RELEASE PLAN

The BSS GSR 4.1 and GSN Release 1 GPRS Planning Guide is beingdeveloped in two draft phases. The first draft contains the BSS planningportion with some introduction to the GSN Complex portion. The second draft

will contain the GSN Complelx portion as well as any needed revisions to theBSS portion. Following the draft phases, the planning guide will beincorporated into the product documentation.

Version Description

1st Draft, BSS section release toMotorola documentation group.

2nd Draft Version 0.8, BSS and GSN

Complex sections release to Motoroladocumentation group. Additionalengineering input to the GSNPlanning section to be added prior tothe 4Q99 release.

BSS GSR 4.1 and GSN Release 1Customer Documentation versionavailable from Motorola.

CAVEATs

The GPRS data throughput and delay informationpresented in this planning guide has not been compared toactual network performance data. This information may berevised after equipment performance testing has beencompleted.

The planning information covering the provision of linksis subject to change following equipment performance testing.

The information in the document is subject to change as

it is reviewed in preparation for customer documentationrelease.


6/163

GPRS PLANNING GUIDE

2. INTRODUCTION

Overview

General Packet Radio Service (GPRS) provides packet switched data

services over GSM. This planning guide provides estimation procedures fordetermining the BSS equipment, GSN Complex equipment, andcommunication links needed to support a given level of GPRS data andsignaling traffic.

The planning rules provided in this document enable a network planner totranslate the expected GPRS traffic load into a list of new equipment and/orupgrades to existing equipment based on the provisioned number of per cellGPRS timeslots.

The Motorola GPRS Infrastructure has two main components, the BSSportion and the GSN Complex portion. It is possible to use the Motorola BSS

elements with another vendors' GSN elements or the Motorola GSN Complexwith another vendors' BSS equipment. Therefore, this planning guideseparates the planning of these two GPRS infrastructure equipment entitiesinto a BSS portion and into a GSN Complex portion.

Network planning of the GPRS Infrastructure will require the considerationof the interaction between the GSM Circuit Switched portion of the networkwith the addition of the GPRS Packet Data portion. This planning guideidentifies the areas where this GSM and GPRS interaction occurs and providessuggestions and rules for how to plan for this interaction. Additionally, thisplanning guide provides a list of BTS equipment that has GPRS compatibleradios and explains under what conditions more equipment should be added

to the GSM infrastructure in support of GPRS provisioning.


7/163

GPRS PLANNING GUIDE

3. ACRONYMS AND TERMS

Acronyms Definition

ACCH Associated Control CHannel

AGCH Access Grant CHannel

APN Access Point Name

Be Burst Excess Rate

Bc Committed Burst Rate

BCCH Broadcast Control CHannel

BH Busy Hour

BLER BLock Error Rate

BS Billing System

BSS Base Station System

BSSGP BSS GPRS Protocol

BTS Base Transceiver Station

BVC BSS Virtual Connection

BVCI BVC Identifier

C/I Carrier-to-Interference ratio

C7 International Signaling System No. 7

CCCH Common Control CHannel

CCU Channel Coding Unit

CF Control Function

CGF Charging Gateway Function

CIR Committed Information Rate

CM Configuration Management


8/163

GPRS PLANNING GUIDE

Acronyms Definition

cPCI Compact PCI

CS-1 Coding Scheme 1 (9.05 Kbps per TCH)

CS-2 Coding Scheme 2 (13.4 Kbps per TCH)

DHCP Dynamic Host Configuration Protocol

DL Down Link

DLCI Data Link Connection Identifier

DNS Domain Name Server

DPROC Data Processor Board

DRX Discontinuous Reception

EIR Equipment Identity Register

FPGA Field Programmable Gate Array

FRU Field Replaceable Unit

FTD File Transit Delay

Gb Interface between the PCU and the SGSN

GBL Gb link

G-CDR GGSN Call Detail Record

GDS GPRS Data Stream

GGSN Gateway GSN

Gi Interface between the GGSN and the PDN

Gn Interface between the SGSN to the GGSN

GOS Grade Of Service

GPRS General Packet Radio Service

GSL GPRS Signaling Links


9/163

GPRS PLANNING GUIDE

Acronyms Definition

GSN GPRS Support Node

GSR GSM System Release

HLR Home Location Register

INS IN Service

ISS Internet Support Server

Kbps Kilo bits per second

Kph Kilometers per hour

KSW Kiloport Switch

LAN Local Area Network

LAPD Link Access Protocol D-channel

LLC Logical Link Control

MAC Medium Access Control

MAP Mobile Application Part

M-CDR Mobility Management Call Detail Record

MM Mobility Management

MO Mobile Originated

Mobis Motorola Abis Inteface

MPROC Master Processor Board

MS Mobile Station

MSC Mobile Switching Center

MSI Multiple Serial Interface

MT Mobile Terminal

MT Mobile Terminated

Nr/sub Number of requests per subscriber


10/163

GPRS PLANNING GUIDE

Acronyms Definition

NSEI Network Service Entity Identifier

NSS GSN Network SubSystem

NS-VC Network Service Virtual Connection

NS-VCI NS-VC Identifier

NTP Network Time Protocol

OMC-G Operation and Maintenance Center-GPRS

OOS Out Of Service

PAGCH Paging and Access Grant Channel

PBCCH Packet Broadcast Control Channel

PCH Paging Channel

PCI Compact Peripheral Component Interconnect

PCU Packet Control Unit

PDCH Packet Data CHannel. Carries a combinationof PBCCH and PDTCH logical channels.

PDN Public Data Network

PDTCH Packet Data TCH

PDU Packet Data Unit

PICP Packet Interface Control Processor

PLMN Public Land Mobile Network

PMC PCI Mezzanine Card

PRP Packet Resource Processor

PSP PCU System Processor

PVC Permanent Virtual Connection

QoS Quality of Service

RACH Random Access Channel


11/163

GPRS PLANNING GUIDE

Acronyms Definition

RAID Redundant Array of Independent Disks

RLC Radio Link Control

RTD RLC-Block-Equivalent Transit Delay

RXCDR Remote Transcoder

S-CDR SGSN Call Detail Record

SDCCH Standalone Dedicated Control CHannels

SFH Slow Frequency Hopping

SGSN Serving GSN

SMS-C Short Message Service Center

SMS-GMSC Short Message Service Gateway MSC

SMS-IWMSC Short Message Service InterWorking MSC

SNDCP Subnet Dependent Control Protocol

SS System Slot

TBF Temporary Block Flow

TCH Traffic Channel

TCP/IP Transmission Control Protocol/InternetProtocol

TDMA Time Domain Multiple Access

TE Terminal Equipment

TRAU Transcoder Rate Adaption Unit

TSW Timeslot Switch

UL Up Link

Um Interface between the BTS and Mobile

VLR Visitor Location Register


12/163

GPRS PLANNING GUIDE

Acronyms Definition

WAN Wide Area Network

Terms Definitions

Access Point Name(APN)

The purpose of the APN information element is toidentify the packet data network to which the GPRSuser wishes to connect. The Access Point Name is alabel or a fully qualified domain name according toDNS naming conventions as specified in GSM 03.03.

Applied Load This is the per cell GPRS application data such asemail that will be carried on GPRS carrier timeslotsfrom all of the mobiles in a cell.

BSSGP BSS GPRS Protocol . The functions of the BSSGP areto provide radio-related information and to performnode management functions between the SGSNand the BSS.

BVC BSSGP Virtual Channel. A data and signalling

communication path across the Gb-interfacebetween remote BSSGP entities.

CommHub This unit provides ethernet switching and IP routingfor the GSN Complex local networking and GSNComplex E1 interfaces to the public data network.

CommunicationsCabinet

This cabinet holds the GSN Complexcommunications equipment: the CommHub,Internet Support Services, and High Availability DiskArrays.

Control FunctionModule (CF) The CF provides the SGSN mobility managementfunctions and OA&M functions. It has a unique IPaddress within the GSN Complex, and is directlyconnected to the CommHub via a 100BaseT port.

Domain NameSystem (DNS)

The DNS is a distributed Internet directory service.DNS is used primarily to translate between logicaldomain or equipment names to IP addresses. InGPRS, an "Access Point Name" (APN) is a form of


13/163

GPRS PLANNING GUIDE

DNS name.

Effective Load This is the true load carried by a cell from all of themobiles after the Applied Load has been wrappedby the GPRS protocols and weighted by theexpected BLER , V.42 bis data compression, and

TCP/IP header compression.

Gb Link The Gb Link is used to carry both GPRS user dataand signaling information by using Frame Relayover E1 between the PCU and SGSN. From one tofour E1s may be provisioned per SGSN.

Gb Module This module provides the SGSN Gb interfacecommunication protocol functions. It has a uniqueIP address within the GSN Complex, and is directlyconnected to the CommHub via a 100BaseT port. Itsupports 4 E1 ports to remotely located BSS sites

and these are referred to as GBL links.

GDS LAPD (GSL) The GSLs are is provisioned over one or two E1sbetween the BSC and PCU. Each GDS LAPD channeluses 64 Kbps of bandwidth on an E1. This LAPD linkwill carry out-of-band GPRS signaling information, PCUstatistics, and other PCU O&M information such assoftware code loads.

GDS TRAU The GDS TRAU is provisioned by the Network Operatorover one to ten E1s between the BSC and PCU. TheseE1s will carry GPRS user data.

GGSN Shelf Unit Provides interworking with external packet-switchednetworks, and isconnected with SGSNs via an IP-based GPRSbackbone network. GGSN functionality is providedwith Cisco 7206 router hardware.

Gn Module This module provides the SGSN communicationprotocol functions for a single Gn interface. It has aunique IP address within the GSN Complex, and isdirectly connected to the CommHub via a 100BaseTport.

GPRS Attach GPRS-Attach is performed when the MS indicates itspresence to the PLMN for the purpose of using theGPRS PTP service. This can be immediately after theMS has been switched on or later as the user decidesto use the GPRS services. The MS identifies itself withits GSM identity (IMSI, TLLI). A GPRS-Attach shall besuccessfully performed only if the subscriber has avalid GPRS subscription. It is assumed that the userwill not, under normal circumstances, initiate a GPRS


14/163

GPRS PLANNING GUIDE

Attach without first ensuring that the data handlingcapability necessary in the terminating equipment hasbeen activated, e.g., laptop computer has beenturned on.

GPRS Detach GPRS-Detach is performed when the MS indicates to

the PLMN that the MS will no longer be using theGPRS services. The MS identifies itself with its GSMidentity (IMSI, TLLI).

GPRS NetworkSubsystem (NSS)

The NSS is responsible for all network managementand mobility related management. The GSN NetworkSubsystem (NSS) may contain the followingcomponents: SGSN, GGSN, ISS, and CGF.

GPRS SupportNode (GSN)Complex

A GSN Complex consists of multiple componentsconnected to asingle CommHub. Some of the components that maybe connected to the CommHub are the: SGSN, GGSN,CGF, and ISS. A GSN Complex is defined by thephysical connection of entities to the communicationshub.

GSN Cabinet This cabinet holds up to three GSN shelf units.

GSN Shelf This is the set of equipment contained within a 19"CompactPCI shelf that is interconnected by the samecPCI bus. In the GSN Release 1 a GSN Shelf containsone C7 card, one to three SGSN modules (CF, Gn, andGb cards) and two Shelf Management Modules.

High AvailabilityDisk System

This disk system provides reliable long-term storagefor network configuration, software loads, chargingdata information and network statistics.

Internet SupportServices

The Internet Support Services equipment performsthe Charging Gateway Function (CGF), Domain NameSystem (DNS), Network Time Protocol (NTP) requiredby a GSN Complex. The ISS uses the Sun Netrahardware, which is connected to the CommHub using100 BaseT. The ISS hardware is located in theCommunications Cabinet.

Module A Module is a self-contained, separable assembly ofelectronic parts and/or software.

Network TimeProtocol (NTP)

The NTP is used to synchronize the time of GSNComplex components. It provides accuracy within amillisecond on LANs and up to a few tens ofmilliseconds on WANs relative to a primary serversynchronized to Coordinated Universal Time (UTC) viaa Global Positioning Service (GPS) receiver.


15/163

GPRS PLANNING GUIDE

SGSN Module This module is a 3-card set of equipment containedwithin a 19" CompactPCI shelf. The 3-card setincludes:

(a) Control Function module,

(b) Gn module and,

(c) Gb module.

Shelf ManagementModule

This is a 2-card set that is located in the GSN shelf.Each Shelf Management module contains a systemslot (SS) processor module (card) and a bus bridgemodule(card). The Shelf Management moduleperforms the bus control functions, enabling thecommunication between non-system slot cards over

the cPCI bus. It also performs the shelf level O&Mfunctions including relaying shelf alarms to the OMC-Gand software load management (BOOTP). Each Shelfcontains two Shelf Management Units (4 cards intotal).

Spare A Module The Spare A module (card) is a field replacementmodule (card) for CF, Gb or C7 modules. It consistsof a non-system slot card and two dual E1 PMCs.

Spare B Module The Spare B module (card) is a field replacementmodule (card) for the Gn module. It consists of a non-system slot card and one PMC encryption module.

C7 Module This module provides the logical interface to the HLR,MSC/VLR (future) and SMS-C (future). An C7 modulehas up to four E1 interfaces which typically connectsto a C7 signaling Transfer Point (STP) pair. The C7Module has a unique address within the GSNComplex, and is directly connected to the CommHubvia a 100BaseT port. In the GSN Release 1, one C7Module is provided for every three SGSN modules.

The C7 Module that serves a particular SGSN Moduleneed not be located in the Same Shelf Module as theSGSN module.


16/163

GPRS PLANNING GUIDE

4 . REFERENCES

[Ref#]

Document Title / Document ID /Version / Release Date

Author(s)

1 GSM 01.04 (ETR 350): "Digital cellulartelecommunications system (Phase 2+);Abbreviations and acronyms", version5.0.0, March 96

ETSI

2 GSM 01.33: "Digital cellulartelecommunications system (Phase 2+);Lawful Interception requirements forGSM", version 7.0.0

ETSI

3 SM 01.61: "Digital cellulartelecommunications system (Phase 2+);GPRS ciphering algorithm requirements",version 6.0.1

ETSI

4 GSM 2.33: "Digital cellulartelecommunications system (Phase 2+);Lawful Interception - Stage 1"; Version7.0.0, 1998-03

ETSI

5 GSM 02.60: "Digital cellulartelecommunications system (Phase 2+);General Packet Radio Service (GPRS);Service description; Stage 1" Version6.1.1

ETSI

6 GSM 03.03 (ETS 300 927): "Digital cellulartelecommunications system (Phase 2+);Numbering, addressing andidentification", version 5.0.0, March 1996

ETSI

7 GSM 03.33 (ETS 300 927): "Digital cellulartelecommunications system (Phase 2+);Lawful Interception - stage 2", version1.1.3, Release 98

ETSI

8 GSM 03.07: "Digital cellulartelecommunications system (Phase 2+);Restoration procedures", Version 5.0.0,November 1996

ETSI

9 GSM 03.22 (ETS 300 930): "Digital cellulartelecommunications system; Functionsrelated to Mobile Station (MS) in idlemode and group receive mode"

ETSI

10 GSM 03.40 (ETS 300 930): "Digital cellulartelecommunications system" ETSI

ETSI

11 GSM 03.60: "Digital cellulartelecommunications system (Phase 2+);

ETSI


17/163

GPRS PLANNING GUIDE

General Packet Radio Service (GPRS);Service Description; Stage 2", Version6.2.0

12 GSM 03.61: "Digital cellulartelecommunications system (Phase 2+);General Packet Radio Service (GPRS);

Point to Multipoint Multicast ServiceDescription; Stage 2", Version 0.7.1

ETSI

13 GSM 03.62: "Digital cellulartelecommunications system (Phase 2+);General Packet Radio Service (GPRS);Point to Multipoint Group Service Point toMultipoint - Groupc Stage 2 Description",version none

ETSI

14 GSM 03.64: "Digital cellulartelecommunications system (Phase 2+);Overall description of the General PacketRadio Service (GPRS) radio interface;Stage 2", version 6.1.0

ETSI

15 GSM 04.04 Digital cellulartelecommunications system; Layer 1;General requirements, (GSM 04.04version 5.1.0

ETSI

16 GSM 04.07 (ETS 300 939): "Digital cellulartelecommunications system (Phase 2+);Mobile radio interface signalling layer 3;General aspects", version 6.2.0

ETSI

17 GSM 04.08: "Digital cellulartelecommunications system (Phase 2+);

Mobile radio interface layer 3specification", version 6.2.0

ETSI

18 GSM 04.60: "Digital cellulartelecommunications system (Phase 2+);General Packet Radio Service (GPRS);Service: MS-BSS interface; Radio LinkControl/Medium Access Control(RLC/MAC) protocol", version 6.2.0

ETSI

19 GSM 04.61: "Digital cellulartelecommunications system (Phase 2+);General Packet Radio Service Point toMultipoint- Multicast Stage 3 description,

version none

ETSI

20 GSM 04.62: "Digital cellulartelecommunications system (Phase 2+);General Packet Radio Service Point toMultipoint- Groupcast Stage 3description, version none

ETSI

21 GSM 04.64: "Digital cellulartelecommunications system; (Phase 2+),General Packet Radio Service (GPRS);

ETSI


18/163

GPRS PLANNING GUIDE

Mobile Station-Serving GPRS SupportNode (MS-SGSN) Logical Link Control(LLC) Layer Specification", version 6.2.0

22 GSM 04.65: "Digital cellulartelecommunications system (Phase 2+);General Packet Radio Service (GPRS);

Subnetwork Mobile Station (MS) - ServingGRPS Support Node (SGSN); SubnetworkDependent Convergence Protocol(SNDCP)", version 6.2.1

ETSI

23 GSM 05.02: "Digital cellulartelecommunications system (GSM RadioAccess Phase 3); Multiplexing andmultiple access on the radio path",version 6.2.0

ETSI

24 GSM 05.03: "Digital cellulartelecommunications system (GSM RadioAccess Phase 3); Channel Coding",version 6.0.0, 1998-01

ETSI

25 GSM 05.05: "Digital cellulartelecommunications system (Phase 2+);Radio Transmission and Receptions",version 5.2.0, July 1996

ETSI

26 GSM 05.08 "Digital cellulartelecommunications system (GSM RadioAccess Phase 3); Radio Sub-system linkcontrol" version 5.1.0, July 1996

ETSI

27 GSM 05.10 "Digital cellulartelecommunications system (Phase 2+);

Radio Sub-system Synchronization",version 5.10, May 1996

ETSI

28 GSM 07.60 "Digital cellulartelecommunications system (Phase 2+);General requirements on Mobile Stationssupporting GPRS"; version 6.2.1

ETSI

29 GSM 08.08: "Digital cellulartelecommunications system (Phase 2+);Mobile Switching Center - Base StationSystem (MSC - BSS) interface: Layer 3specification", version .6.3, September1997

ETSI

30 GSM 08.14: "Digital cellulartelecommunications system BSS-SGSNinterface Gb Interface Layer 1", version6.3.0

ETSI

31 GSM 08.16: "Digital cellulartelecommunications system (PHASE 2+);General Packet Radio Service (GPRS);Base Station System (BSS) - Serving GPRSSupport Node (SGSN) interface; Network

ETSI


19/163

GPRS PLANNING GUIDE

Services", version 6.3.032 GSM 08.18: "Digital cellular

telecommunications system (Phase 2+)General Packet Radio Service (GPRS);Base Station System (BSS) - ServingGPRS Support Node (SGSN); BSS GPRS

Protocol (BSSGP)", version 6.3.0

ETSI

33 GSM 08.60 (ETS 300 737): "Digital cellulartelecommunications system (Phase 2+);Inband control of remote transcoders andrate adaptors for Enhanced Full Rate(EFR) and full rate traffic channels"

ETSI

34 GSM 09.02 (ETS 300 974): "Digital cellulartelecommunications system (Phase 2+);Mobile Application Part (MAP)specification", version 6.2.0

ETSI

35 GSM 09.16 (ETS 300 974): "Digital cellulartelecommunications system (Phase 2+);SGSN-MSC, Gs Interface Layer 2", version6.0.1

ETSI

36 GSM 09.18: "Digital cellulartelecommunications system SGSN-MSC;Gs Interface Layer 3", version 6.2.0

ETSI

37 GSM 09.60: "Digital cellulartelecommunications system (Phase 2+);General Packet Radio Service (GPRS);GPRS Tunnelling Protocol (GTP) across theGn and Gp Interface", version 6.2.2

ETSI

38 GSM 09.61: "Digital cellular

telecommunications system (Phase 2+);General Packet Radio Service (GPRS);Interworking between the Public LandMobile Network (PLMN) supporting GPRSand Packet Data Networks (PDN)", version6.3.0

ETSI

39 GSM 10.18: "Digital cellulartelecommunications system (Phase 2+)General Packet Radio Service (GPRS)O&M in GPRS", version 0.2.0, 1997-11

ETSI

40 GSM 10.60: "Digital cellulartelecommunications system (Phase 2+)

General Packet Radio Service (GPRS)Project scheduling and open issues",version 5.3.0, 1997-10

ETSI

41 GSM 12.00: "Digital cellulartelecommunications system (Phase 2)Network Management (NM) Part 1: Objectand structure of Network Management(GSM 12.00)"; prETS 300 612-1; FinalDraft; August 1996

ETSI


20/163

GPRS PLANNING GUIDE

42 GSM 12.06: "Digital cellulartelecommunications system (Phase 2)SGSM Network configurationmanagement (GSM 12.06)"; prETS 300617; Final Draft; June 1996

ETSI

43 GSM 12.08: "Digital cellular

telecommunications system (Phase 2)Subscriber and equipment trace";version5.1.1, release 1996

ETSI

44 GSM 12.12: "Digital cellulartelecommunications system (Phase 2)

ETSI

45 GSM 12.15: "Digital cellulartelecommunications system (Phase 2)GPRS Charging"; version 6.1.0

ETSI

46 CCITT Recommendations I.130: "Generalmodelling methods - Method for thecharacterization of telecommunicationservices supported by an ISDN andnetwork capabilities of an ISDN"

ETSI

47 CCITT Recommendation E.164:"Numbering plan for the ISDN era"

ETSI

48 CCITT Recommendation Q.65:"Methodology - Stage 2 of the method forthe characterization of services supportedby an ISDN"

ETSI

49 ITU-T Q.922: "ISDN data link layerspecification for frame mode bearerservices.", 2/92

ITU-T

50 ITU-T Q.933: "Digital Subscriber Signalling

System No. 1 (DSS 1) - Signallingspecification for frame mode basic callcontrol", 10/95

ITU-T

51 CCITT Recommendation V.42 bis: "Datacommunication over the telephonenetwork - Data compression proceduresfor data circuit-terminating equipment(DCE) using error correction procedures"

ETSI

52 CCITT Recommendation X.3: "Packetassembly disassembly facility (PAD) in apublic data network"

ETSI

53 CCITT Recommendation X.25: "Interface

between data terminal equipment (DTE)and data circuit-terminating equipment(DCE) for terminals operating in thepacket mode and connected to publicdata networks by dedicated circuit"

ETSI

54 CCITT Recommendation X.121:"International Numbering Plan for PublicData Networks"

ETSI

55 CCITT Recommendation X.137: ETSI


21/163

GPRS PLANNING GUIDE

"Availability Performance Values forPublic Data Networks When ProvidingInternational Packet Switched Services";Melbourne, 1988

56 CCITT Recommendation X.733: "SystemManagement Event Reporting Function"

ETSI

57 CCITT Recommendation X.734: "SystemManagement Alarm Reporting Function"

ETSI

58 prETS 300 019-1-2: "EquipmentEngineering (EE); Environmentalconditions and environmental tests fortelecommunications equipment Part 1-2:Classification of environmental conditions

Transportation"; Edition 1; February 1992

ETSI

59 prETS 300 019-1-3: "EquipmentEngineering (EE); Environmentalconditions and environmental tests fortelecommunications equipment Part 1-3:Classification of environmental conditionsStationary use at weather protectedlocations"; Edition 1; February 1992

ETSI

60 prETS 300 753 019-1-3: "EquipmentEngineering (EE); Environmental

ETSI

61 IETF RFC 768 (1980): "User DatagramProtocol" (STD 6)

ETSI

62 IETF RFC 791 (1981): "Internet Protocol"(STD 5)

ETSI

63 IETF RFC 792 (1981): "Internet ControlMessage Protocol" (STD 5)

ETSI

64 IETF RFC 793 (1981): "TransmissionControl Protocol" (STD 7) ETSI

65 IETF RFC 854 (1981): "TELNET" ETSI

66 IETF RFC 1034: "Domain names -concepts and facilities"

ETSI

67 IETF RFC 1035: "Domain names -implementation and specifications"

ETSI

68 IETF RFC 1144: "Compressing TCP/IPHeaders for Low-Speed Serial Links"

ETSI

69 IETF RFC 1305: "Network Time ProtocolSpecification, Implementation and

Analysis"

ETSI

70 IETF RFC 1155: "SMI" ETSI

71 IETF RFC 1157: "SNMP" ETSI

72 IETF RFC 1631: "The IP Network AddressTranslator (NAT)"

ETSI

73 IETF RFC 1825: "Security Architecture forthe Internet Protocol"

ETSI


22/163

GPRS PLANNING GUIDE

74 IETF RFC 1826: "IP AuthenticationHeader"

ETSI

75 IETF RFC 1827: "IP Encapsulating SecurityPayload (ESP)"

ETSI

76 IETF RFC 1212: "MIB Definition" IETF

77 IETF RFC 1215: "Trap Definition" IETF

78 IETF RFC 220: "Internet Official ProtocolStandards", June 1997 (STD)

IETF

79 FRF 1.1: "The Frame Relay Forum User-to-Network Implementation Agreement(UNI)", January 1996

Forum

80 Motorola: "Impact of the Radio Interfaceon GPRS System Dimensioning - aSimulation Study", Draft 0.1, June 1999.

Phil Jones

81 Recommendation G.703,

"Physical/Electrical Characteristics ofHierarchical Digital Networks", Sept.1991.

ITU-T

82 Recommendation G.704, "SynchronousFrame Structures Used at Primary andSecondary Hierarchical Levels", Oct.1991.

ITU-T


23/163

GPRS PLANNING GUIDE

5. GPRS FEATURES SUPPORTED

The addition of GPRS to an existing GSM network is a significant task. As aresult, many of the system capabilities that the GPRS standards cover will beadded as the standards are refined and the development of those features is

made possible. A summary of the features supported in BSS GSR 4.1 and GSNRelease 1 are listed below for the BSS, GSN Complex, and OMC-G. Not all ofthese features impact the Network Planning process. The value supported islisted after the colon in the following list of features.

5.1.BSS

Network Operation Mode: 2, (i.e., CCCH used for both GSM &GPRS traffic)

System Information: 1-8: 13.

CS-1 (9.05kbit/s) & CS-2 (13.4kbit/s) transmission rates.

Mobile multislot classes: 1-12, 19, 20.

Full Duplex Mode: Up to 4 Downlink Time slots persubscriber supported.

Full Duplex Mode: Up to 4 Uplink Time slots per subscribersupported.

Half Duplex Mode: 6 DL and 2 UL Time slots per

subscriber supported.

The BSS will treat Class A mobiles as Class B mobiles.

1 GPRS Carrier per Cell.

Signaling on GSM signaling channels, i.e., BCCH/CCCH only andnot on PBCCH/PCCCH.

Medium Access Mode Allocation: Fixed & Dynamic.

Switchable Timeslots, i.e., timeslots useable by both circuit

switched and GPRS traffic.

Reserved GPRS Timeslots.

Frequency Hopping of PDCH.

DRX: Standard (GSM paging groups supported)


24/163

GPRS PLANNING GUIDE

Gb Interface supported with the Frame Relay protocol.

5.2.GSN COMPLEX

Class A, B, & C Mobiles supported on Attach.

The SGSN will treat all mobiles as Class C devices.

Mobile support in Mode A is restricted to Circuit Switch Mode orGPRS Mode operation.

QoS Profile Class

Precedence(1-3): 2 (Normal).

Delay(1-4): 4 (Best Effort).

Reliability(1-5): 3(Unacknowledged LLC Frame Mode, GTP mode,

protected LLC Data, and acknowledged RLC Blockmode).

Peak Throughput(1-9): 1,2, or 3(8-32 Kbit/s at the Gi andR interfaces).

Mean Throughput(1-19): 1 (Best Effort).

V.42bis Data Compression.

TCP/IP Header Compression.

Encryption support to MS and to PDN.

Gb Interface supported with the Frame Relay protocol.


25/163

GPRS PLANNING GUIDE

5.3.OMC-G

Load Management

Fault Management

Alarm Filtering.

Comment Field.

Configuration Management

Propagation.

CM Data Export.

Security Management

OMC-G Access Control.

OMC-G Users per Region.

Performance Management

Background Statistics.

Statistics collected on demand and by polling.

Open statistics interface to 3rd party statistics collectionsoftware products.


26/163

GPRS PLANNING GUIDE

6. GPRS INTERFACES

The existing GSM network elements and the new GPRS elements areconnected together as shown in the following network diagram. Motorola has

developed new hardware (PCU) that is part of the BSS in support of GPRSwith the new GPRS Gb interface. The GPRS Charging Gateway Function (CGF),SGSN, GGSN, and OMC-G elements which comprise the GSN Complex are alsoavailable from Motorola as part of the new GPRS network solution.

The EIR, HLR, MSC, SMS, VLR, and Billing System are Non-Motorolaelements.

Gf

D

Gi

Gn

Gb

Gc

CE

Gp

Gs

Signalling and Data Transfer Interface

Signalling Interface

MSC/VLR

TE MT BSS TEPDN

R Um

GrA

HLR

Other PLMN

SGSN

GGSN

Gd

SM-SCSMS-GMSC

SMS-IWMSC

GGSN

EIR

SGSN

Gn

Figure 1

Overview of the GPRS Logical Architecture

Ga CGF BS

SMS-


27/163

GPRS PLANNING GUIDE

7. MOTOROLA GSM / GPRS NETWORK ARCHITECTURE

The Motorola specific implementation of GPRS, as integrated with theexisting GSM infrastructure equipment, is shown in the following networkarchitecture diagram in Figure 2. The new GPRS equipment consists of a PCU

attached to the BSC as part of the BSS. The SGSN, GGSN, CommHub, and ISSare included as part of the GSN Complex equipment. Each BSC has adedicated PCU and multiple BSSs can be attached to one GSN Complex.Several GSN Complexes can be networked together to serve one PLMN. OneOMC-G can manage several GSN Complexes. The GSN networkingcapabilities and connectivity options are discussed in the GSN ComplexPlanning section of the planning guide.

Figure 2

GSM / GPRS Network Architecture

PCU BSC

RXCDR

OMC-

MSC HLR PDN

Billin

g

LawfulIntercept

Administration Node

OMC-G

SGS GGS

BTSs

BSSs

GSNComplexes

New GPRS equipment provided by

GSM Equipment GPRS

CommHu

IS

RadiusServer(non-

ISS Functions:- Charging Gateway Function- Domain Name System- High Availability Disk Arraymirroring

Software upgrade required

OperatorServerComplex- Radius Server(Operator isISP, i.e.,

TransparentMode)


28/163

GPRS PLANNING GUIDE

8. MOTOROLA PRODUCTS AND INTERFACES SUPPORTED

The Motorola BSC, Remote Transcoder, and OMC-R equipment support theGPRS Network feature with the appropriate software upgrades. The MotorolaBase Station Radio Products and new products that support GPRS are:

8.1.EXISTING BTS PRODUCTS

Macro Platforms: InCell, M-Cell2, M-Cell6, Horizonmacro.

Micro Platforms: M-Cellarena, M-Cellcity, Mcellmicro,Horizoncompact

Pico Platforms: M-Cellaccess, Horizonoffice.

All existing BTS radios support GPRS except the InCell DRCU-1.The DRCU-1 must be replaced by a DRCU-2 or later radio in the InCell

product.

8.2.NEW PRODUCTS

BSS: PCU.

GSN Complex: CommHub, GGSN, ISS, LIAN, SGSN.

OMC-G.


29/163

GPRS PLANNING GUIDE

8.3.INTERFACES SUPPORTED

Table 1

Reference Description Comments

A BSS to MSC Supported

Mobis BTS to BSC Supported

Ga GGSN to Charging Gatewayand Billing System

Proprietary interface untilstandardized

Gb BSS to SGSN Supported

Gc GGSN to HLR Future Release

Gd SGSN to SMS Future Release

Gf SGSN-EIR Future Release

Gi GGSN to other PDNs Supported

Gn SGSN to GGSN Supported

Gp SGSN to other PLMN GGSN Future Release

Gr SGSN to HLR Supported

Gs SGSN to MSC/VLR Future Release

Um Mobile to BTS Supported


30/163

GPRS PLANNING GUIDE

9. THE PLANNING PROCESS

The planning process begins by determining the expected GPRS load

(applied load) to the system. The next step is to determine the effective loadto the system by weighting the applied load by network operatingparameters. These parameters consist of the expected Block Error Rate(BLER) based on the cell RF plan, by the Protocol Overhead (GPRS protocolstack i.e., TCP/IP, LLC, SNDCP, RLC/MAC), by the expected advantage fromV.42bis compression and TCP/IP Header compression, and by the multislotoperation of the mobiles and infrastructure.

The effective load at a cell is used to determine the number of GPRStimeslots required to provision a cell. The provisioning process can beperformed for a uniform load distribution across all cells in the network or onan individual cell basis for varying GPRS cell loads. The number of GPRS

timeslots is the key piece of information that drives the BSS provisioningprocess in support of GPRS.

The planning process will also use network generated statistics, availableafter initial deployment, for re-planning a network. The statistics fall into twocategories, PCU specific statistics and GSN Complex (SGSN + GGSN)statistics. In a later section of this document all of the statistics collectedfrom the GPRS infrastructure are listed and the statistics that are expected tobe useful for network re-planning are identified. The Statistics used forplanning purposes are grouped, in this planning document, into fourcategories; Stats_A, Stats_B, Stats_C, and Stats_D as indicated in thefollowing flow chart.

GPRS Network Planning Flow Chart

Figure 3Enter UserProfile

(AppliedLoad)

BSS/PCU/GS

N Stats_A

Calculate BLER &Protocol Overhead

impact on AppliedLoad

(Effective Load)

BSS/PCU/GSN Stats_B

ConfigureInfrastructure

BSS /PCU

Provisioning

GSN

(SGSN, GGSN,OMC-G)

Provisioning

GSNStats_C

BSS/PC

UStats_D


31/163

GPRS PLANNING GUIDE

The rest of the planning guide is presented in support of the above GPRSNetwork Planning Flow Chart. The Network Planning flow is as follows:

GPRS Network Traffic Estimation and Key concepts : This sectionis intended to introduce the key concepts involved in planning anetwork. Because GPRS introduces the concept of a switchabletimeslot that can be shared by both the GSM circuit switchedinfrastructure and by the GPRS infrastructure, a good part of thissection is dedicated to the discussion of this topic.

Customer Inputs to the Planning Process : This section provides atable of inputs that can serve as a guide in the planning process. Insubsequent planning sections, references are made to parameters inthis table. A key piece of information that is needed for the planningprocess is the RF cell plan. This subsection discusses the impact ofdifferent cell plans on the GPRS provisioning process and how to usethis information in order to determine the number of GPRS timeslotsthat will be required on a per cell basis.

BSS Planning: The hardware and communication linkprovisioning rules are given in this section based on the number oftimeslots required. The number of timeslots is determined from theapplied cell load requirements (cell throughput) that are provided bythe Network Planner.

GSN Complex Planning: The hardware and communication linksare determined in this section.

GPRS Network Statistics for Network Re-Planning: The statisticscollected by the BSS and GSN Complex are listed in tabular form and

the statistics that could be valuable for network re-planning areidentified.

Planning Examples: A planning example is provided for both theBSS and GSN Complex portions of the GPRS infrastructure.

Recommended Planning Guidelines: Based on the networkplanning rules, a few recommended planning guidelines are providedin this section.


32/163

GPRS PLANNING GUIDE

10. GPRS NETWORK TRAFFIC ESTIMATION AND KEY CONCEPTS

The GPRS network planning is fundamentally different from the planningof circuit switched networks. One of the fundamental reasons for thedifference is that a GPRS network allows the queuing of data traffic instead of

just blocking a call when a circuit is unavailable. Consequently, the use ofErlang B tables for estimating the number of trunks or timeslots required isnot a valid planning approach for the GPRS packet data provisioning process.

The GPRS traffic estimation process starts by looking at the per cell GPRSdata traffic profile such as fleet management communications, emailcommunications, web browsing, and large file transfers. Once a typical datatraffic profile mix is determined, then the required network throughput percell can be calculated as measured in Kbits per second. The desired networkthroughput per cell is used to calculate the number of GPRS timeslotsrequired to support this throughput on a per cell basis.

The estimated GPRS network delay is derived based on computermodeling of the delay between the Um interface and the Gi interface and theresults are provided in the planning guide. The network delay can be used todetermine the mean or average time it will take to transfer a file of anarbitrary length. In order to simulate the delay, the following factors areconsidered: traffic load per cell, mean packet size, number of available GPRScarrier timeslots, distribution of CS-1 and CS-2 rate utilization, distribution ofmobile multislot operation (1,2,3, or 4) and BLER.

The use of timeslots on a GPRS carrier is different from how they are usedin the GSM circuit switched case. In circuit switched mode, an MS is either inthe idle mode or dedicated mode. In the dedicated mode, a circuit is

assigned through the infrastructure whether or not a subscriber istransporting voice or data. In the Idle mode, the network knows where the MSis, but there is no circuit assigned. In the GPRS mode, a subscriber uses theinfrastructure timeslots for carrying data only when there is data to be sent.However, the GRPS subscriber can be attached and not sending data and thisstill presents a load to the GSN Complex portion of the GRPS system andmust be accounted for when provisioning the GPRS infrastructure, ie., inState 2 as explained below.

The GPRS Mobile states and conditions for transferring between states areprovided in Table 2 below in order to specify when infrastructure resourcesare being used to transfer data. The comment column specifies what the load

on the infrastructure equipment will be for that state and only in State 3 doesthe infrastructure equipment actually carry user data. The infrastructureequipment is planned such that many more mobiles can be attached to theGPRS network, that is in State 2, than there is bandwidth available tosimultaneously transfer data. One of the more significant input decisions forthe network planning process is to determine and specify how many of theattached mobiles will actively be transmitting data in the Ready State 3. Inthe Standby State 2, no data is being transferred but the mobile is using


33/163

GPRS PLANNING GUIDE

network resources to notify the network of its location. The infrastructure hasequipment limits as to how many mobiles that can be in State 2. When themobile is in State 1, the only required infrastructure equipment support is thestorage of mobile records in the HLR.

Network provisioning requires planning for traffic channels and for

signaling channels also referred to as control channels. The BSS GSR 4.1release combines the circuit switched and GPRS control channels together asBCCH/CCCH. This planning guide provides a planning procedure in a latersection for determining the BCCH/CCCH control channel capacity needed.


34/163

GPRS PLANNING GUIDE

MM State Model of MS

Table 2

Present

State#

PresentState

Next State Condition for StateTransfer

Comments

(Present State)

1 IDLE READY(3) GPRS Attach Subscriber is notmonitored by theinfrastructure, i.e., notattached to GPRS MM,and therefore doesnot load the systemother than the HLRrecords.

2 STANDBY READY(3) PDU Transmission Subscriber is attachedto GPRS MM and isbeing activelymonitored by theinfrastructure, i.e., MS& SGSN establish MMcontext forsubscriber's IMSI, butno data transmissionoccurs in this state.

3 READY IDLE(1) GPRS Detach Data transmissionthrough the

infrastructure occursin the READY state

3 READY STANDBY(2) Ready timer expiry

Or

Force to Standby

(The Network or the

MS can send a GMMsignaling message to

invoke Force toStandby)

The Ready Timer(T3314) default timeis 32 Seconds. Thetimer value can bemodified during thesignaling process by

mobile request.

2-60 sec. in 2 sec.Incr.

or

61-1800 sec. in 60


35/163

GPRS PLANNING GUIDE

sec. Incr.


36/163

GPRS PLANNING GUIDE

10.1. DYNAMIC TIMESLOT MODE SWITCHING

This section proposes a network planning approach when utilizing dynamic timeslot mode switching of

timeslots on a GPRS carrier. The radio interface resources can be shared dynamically between the GSM

Circuit Switched services and GPRS Data services as a function of service load and operator preference.

The timeslots on a GPRS carrier can be reservedfor GPRS use, for circuit switched use only, or allocated

asswitchable. Motorola uses the term switchable to describe a timeslot that can be dynamically allocated

for GPRS Data service or for Circuit Switched service.

The timeslot allocation is performed such that the GPRS reserved timeslots are allocated for GPRS use

before switchable timeslots. GSM circuit switched timeslots are allocated to the circuit switched calls

beforeswitchable timeslots. The switchable timeslots are allocated with priority given to circuit switchedcalls.

Motorola has a BSS feature called "Concentration at BTS. This feature enables the terrestrial backhaul

resources to be dynamically assigned over the E1 links between the BSC and BTS. The terrestrial backhaul

resources are managed and allocated in increments of 16Kbps.

When the "Concentration at BTS" feature is enabled, it is important to have a sufficient level of terrestrial

backhaul resources provisioned. This feature has the concept of reserved and switchable BSC-to-BTS

resources. This "Concentration at BTS" feature allows the Network Planner to allocate dedicated or

reserved backing pools to reservedGPRS timeslots so that there is a guaranteed level of terrestrial backing

available to GPRS traffic. It is recommended that the reserved backing pool be made large enough to servethe expected busy hour GPRS traffic demands on a per BTS site basis.

It is possible for the Circuit Switched portion of the network to be assigned all of the switchable terrestrial

backing under high-load conditions and in effect, block GPRS access to the switchable timeslots at the

BTS. In addition, the reservedGPRS pool of backing resources can be taken by the circuit switched portion

of the network when BSC-to-BTS E1 outages occur and when emergency preemption type of calls occur

and can't be served with the pool of non-reserved resources. The "Concentration at BTS" feature will not

take the last switchable backhaul timeslot until all of the GPRS traffic has be transmitted, in the case when

there are no provisioned reservedGPRS timeslots at the cell site. Provisioning rules for the "Concentration

at BTS" feature are described in the BSS Planning Guide.

10.2. BACKGROUND AND DISCUSSION

The initial Motorola BSS GPRS infrastructure product permits up to onecarrier per cell to be provisioned as a GPRS carrier. The GPRS carrier can alsobe the BCCH/CCCH carrier. Alternatively, the GPRS carrier can be specified touse all 8 timeslots for GPRS traffic and one of the GSM circuit switchedcarriers in the cell can be designated as the BCCH/CCCH carrier.


37/163

GPRS PLANNING GUIDE

The GPRS carrier can be provisioned to carry a mix of circuit switchedtraffic and GPRS traffic. There are three provisioning choices:

reservedGPRS timeslots allocated for GPRS only use,

switchable timeslots dynamically allocated for either GSM circuit switchedtraffic or GPRS traffic (designated as switchable timeslots by Motorola)and,

Remaining GPRS carrier timeslots, if any, for Circuit Switched use only.

The BSS supports a user definable number of GPRS timeslots andreserved GPRS timeslots. The BSS calculates the number of switchabletimeslots by taking the number of operator allocated GPRS timeslots minusthe number of operator allocated reservedGPRS timeslots. The number ofcircuit switched timeslots on a non-BCCH GPRS carrier is equal to eighttimeslots minus the number of GPRS timeslots, i.e., GPRS timeslots includesreservedplus switchable timeslots.

The Network Planner may have some of the following network planning goalsin mind when trying to determine when to use reservedtimeslots versuswhen to use switchable:

use reservedtimeslots to guarantee a minimum GPRS Quality of Service,

use switchable timeslots to provide low circuit mode blocking and highGPRS throughput if the voice busy hour and the GPRS busy hour do not

coincide, use switchable timeslots to provide higher GPRS throughput without

increasing the circuit switched blocking rate1,

use switchable timeslots to provide some GPRS service coverage in lowGPRS traffic volume areas, and

use switchable timeslots to provide extra Circuit Switched capacity inspectrum limited areas.

In order to make the decision on how to best allocate reservedandswitchable timeslots, the Network Planner needs to have a good idea of thetraffic level for both services. The proposal in this planning guide is to drivethe allocation ofswitchable timeslots and reservedGPRS timeslots from acircuit switched point of view.

That is, start by looking at the circuit switched Grade of Service objectivesand the busy hour traffic level, as measured in Erlangs. Once the circuit

1 If all of the GPRS Carrier timeslots are provisioned as switchable, then the last availabletimeslot is not given to a circuit switched call until transmission of all the GPRS traffic on thatlast timeslot is completed. Therefore, there will be circuit switched blocking on that lasttimeslot until the timeslot is freed up.


38/163

GPRS PLANNING GUIDE

switched information is known, the potential impact on switchable timeslotscan then be analyzed. The GPRS Quality of Service can be planned for bycounting the number of available reservedGPRS timeslots and by evaluatingthe expected utilization of the switchable timeslots by the circuit switchedportion of the network during the GPRS busy hour.


39/163

GPRS PLANNING GUIDE

10.3. CARRIER TIMESLOT ALLOCATION EXAMPLES

The following 2-carrier configuration examples explore different ways a 2-carrier system may provision switchable and reserved GPRS timeslots. Allblank timeslots in the following figures are available for circuit switched

traffic use only. The BSS starts the reservedGPRS timeslot allocation at thetop of the carrier (timeslot 7) and then allocates the switchable timeslotsfollowed by circuit switched use only timeslots.

When GPRS and GSM signaling requirements are added together to beserved by a 2-carrier cell, it is highly likely that one timeslot will be used forBCCHand another timeslot allocated as an SDCCH timeslot. Therefore, thefollowing examples A through E assume that there is an extra timeslotallocated as an SDCCH timeslot (SD) for GSM signaling purposes.

In Example A Figure 4, only four timeslots are used for GPRS on carrier 1;two are reservedGPRS timeslots (R) and two are switchable timeslots (S).

One timeslot is used for BCCH(B) and another timeslot for SDCCH (SD) andtwo timeslots for circuit switched only use(Blank).

In Example B Figure 5, the GPRS signaling information is carried on theBCCH (B) of carrier 1 and SDCCH GSM signaling on a separate timeslot(SD). Aseparate carrier (Carrier 2) is used to carry the GPRS data traffic. In thisexample, three timeslots are reservedGPRS timeslots and two are switchable(S). The remaining three timeslots on the second carrier are for circuitswitched only use(Blank).

In Example C Figure 6, all GPRS timeslots are configured as switchabletimeslots on the BCCH carrier 1 and no reserved GPRS timeslots are

configured. Again, one timeslot is assigned for SDCCH signaling use.

In Example D Figure 7, all GPRS timeslots are configured as switchabletimeslots on the non-BCCH carrier, carrier 2.

In Example E Figure 8, all eight GPRS timeslots are configured as reservedtimeslots on the non-BCCH carrier, carrier 2.


40/163

GPRS PLANNING GUIDE

Timeslot Allocation:

B- BCCH/CCCH timeslot for GPRS/GSM signaling

SD- SDCCH timeslot for GSM signaling

R - Reserved GPRS timeslot

S - Switchable timeslot

Blank - Circuit Switched use only timeslots

10.3.1.EXAMPLE A

Figure 4

Carrier 1

B SD S S R R

TS0

Carrier 2 (Circuit Switched only)

10.3.2.EXAMPLE B

Figure 5


B SD

TS0

Carrier 2

S S R R R


41/163

GPRS PLANNING GUIDE

Timeslot Allocation:

B - BCCH/CCCH for GPRS/GSM signaling

SD- SDCCH for GSM signaling

R - Reserved PDCH

S - Switchable PDCH

Blank - Circuit Switched use only timeslots

10.3.3.EXAMPLE C

Figure 6

Carrier 1

B SD S S S S

TS0


10.3.4.EXAMPLE D

Figure 7


B SD

TS0

Carrier 2

S S S S S


42/163

GPRS PLANNING GUIDE

10.3.5.EXAMPLE E

Figure 8


B SD

TS0

Carrier 2

R R R R R R R R


43/163

GPRS PLANNING GUIDE

10.4. BSS TIMESLOT ALLOCATION METHODS

The BSS algorithm that is used in order to determine allocation ofswitchable timeslots gives priority to circuit switched calls. Consequently, if aswitchable timeslot is being used by a GPRS mobile and a circuit switched call

is requested after all othercircuit switched timeslots are used, the BSS willtake the timeslot away from the GPRS mobile and give it to the circuitswitched mobile.

The switchable timeslot can then be re-allocated back to the GPRS mobilewhen the circuit switched call ends. The number ofreservedGPRS timeslotscan be changed by the operator in order to guarantee a minimum number ofdedicated GPRS timeslots at all times. The operator provisions the GPRScarrier by selecting the number of timeslots that are allocated as reservedand switchable and not by specifically assigning timeslots on the GPRS

carrier.

Motorola has implemented an idle circuit switched parameter that enablesthe operator to strongly favor circuit switched calls from a networkprovisioning perspective. By setting the idle parameter to 0, this capability isessentially turned off.

The use of the idle circuit switched parameter is as follows. When a circuit

switched call ends on a switchable GPRS timeslot and the number of idlecircuit switched timeslots is greater than an operator settable threshold, theBSS will then re-allocate the borrowed timeslot for GPRS service. If thenumber of idle timeslots is less than or equal to a programmable threshold,then the BSS will not allocate the timeslot back for GPRS service, even if itsthe last available timeslot for GPRS traffic.

If the BSS needs to use the last switchable timeslot in a cell for a circuitswitched call when all of the timeslots are allocated as switchable, then re-allocation of the timeslot to circuit switched must wait until there is no GPRS

traffic in the cell. There is no GPRS traffic in the cell when all of the GPRSuplink and downlink BSS infrastructure queues are empty. At this point, theBSS can then re-allocate the last switchable timeslot back as a circuitswitched timeslot. If one or more timeslots in a cell are allocated as reserved,then the last switchable timeslot is allocated immediately on demand for acircuit switched call.


44/163

GPRS PLANNING GUIDE

Multislot mobile operation requires that contiguous timeslots be available.The BSS will take the lowest numbered switchable timeslot in such a manneras to maintain contiguous GPRS timeslots for multislot GPRS operation. TheBSS will attempt to allocate as many timeslots as requested in multislot modeand then backoff from that number as timeslots are not available. Forexample, suppose that Timeslots 3 & 4 are switchable, and Timeslots 5,6,& 7

are GPRS reserved (see Figure 9 below). If the BSS needs to re-allocate aswitchable timeslot from GPRS mode to circuit switched mode, then the BSSwill assign Timeslot 3 before it assigns Timeslot 4 for Circuit Switched mode.

CircuitSwitched

Timeslot0

CircuitSwitched

Timeslot1

CircuitSwitched

Timeslot2

Switchable

Timeslot 3

Switchable

Timeslot 4

GPRS

Reserved

Timeslot5

GPRS

Reserved

Timeslot6

GPRS

ReservedTimeslot7

Figure 9

GPRS Carrier with Reserved and Switchabletimeslots

If the Emergency Call Preemption feature is enabled, the BSS will selectthe air timeslot that will carry the emergency call from the following list:(most preferable listed first)

1. Idle circuit switched,

2. Idle or in-service switchable GPRS timeslot (from lowest to highest),

3. In-servicecircuit switched,

4. Idle or In-service ReservedGPRS timeslot (from lowest to highest).

Provisioning the network with switchable timeslots can offer flexibility inthe provisioning process for combining circuit switched and GPRS service.

This flexibility is in the form of additional available network capacity to boththe circuit switched and GPRS subscribers, but not simultaneously. Becausethe BSS favors circuit switched use of the switchable timeslots, the NetworkPlanner should examine the demand for switchable timeslots during thecircuit switched busy hour and during the GPRS busy hour.

Normally the operator provisions the circuit switched radio resource for aparticular Grade of Service (GOS) such as 2%. This means that 2 out of 100circuit switched calls will be blocked during the busy hour. If the operator


45/163

GPRS PLANNING GUIDE

chooses to use the new switchable timeslot capability, it is now possible toshare some GPRS carrier timeslots between the circuit switched calls and theGPRS calls.

During the circuit switched busy hour, the circuit switched use of theseswitchable timeslots can dominate their use. The circuit switched side of the

network has priority use of the switchable timeslots and will attempt toprovide a better Grade Of Service (GOS) as a result of the switchabletimeslots being available.

The following Table 3 example assumes that the planning is beingperformed for a cell that has two carriers. The first carrier is for circuitswitched use only as shown in Figure 10. The second carrier is a GPRS carrierand all eight timeslots are configured as switchable as shown in Figure 11.

The table was created using the Erlang B formula in order to determinehow many circuit switched timeslots are required for a given Grade OfService (GOS). The table covers the range of 2 Erlangs to 9 Erlangs of circuit

switched traffic in order to show the full utilization of two carriers for circuitswitched calls. The purpose of the table is to show how the circuit switchedside of the network will allocate switchable timeslots during the circuitswitched busy hour in an attempt to provide the best possible GOS, assumedto be 0.1% for the purposes of this example.

The comments column in the table is used to discuss what is happening tothe availability of switchable timeslots for GPRS data use as the circuitswitched traffic increases, as measured in Erlangs.

This example does show some Erlang traffic levels that cannot beadequately served by two carriers at the stated Grade Of Service listed in the

tables. This occurs at the 7 and 8 Erlang levels for 0.1% GOS. In these cases,all of the switchable timeslots are used up on the second carrier in anattempt to reach a 0.1% GOS. For the 9 Erlang traffic level, 2 carriers is notenough to serve the circuit switched traffic at a 2% GOS. This would indicatea need for a second circuit switched carrier in addition to the first circuitswitched carrier and the GPRS carrier.


46/163

GPRS PLANNING GUIDE

Assumptions:

2 Carrier site,

Figure 10

1 Circuit switched carrier - with 1 BCCH/CCCH timeslot, 1 SDCCH timeslot& 6 TCH timeslots.

BCCH/CCCH

Timeslot0

SDCCH

Timeslot 1

CircuitSwitched

Timeslot2

CircuitSwitched

Timeslot2

CircuitSwitched

Timeslot4

CircuitSwitched

Timeslot5

CircuitSwitched

Timeslot6

CircuitSwitched

Timeslot7

Figure 11

1 GPRS carrier with all timeslots (8 TCHs) designated as switchable.

Switchable

Timeslot0

Switchable

Timeslot1

Switchable

Timeslot2

Switchable

Timeslot3

Switchable

Timeslot4

Switchable

Timeslot5

Switchable

Timeslot6

Switchable

Timeslot7

Table 3

Switchable Timeslot Utilization

GOS PlannedCircuitSwitchedErlangsper Cell

Total No.of CircuitSwitchedtimeslotsrequiredincludingswitchable

No. of Switchabletimeslotsnecessary toprovide GOS

Comments

2% 2 6 0 During off busy hour time

periods, the GPRS carrier willmost likely carry only GPRStraffic. Therefore, GPRSnetwork planning should beperformed assuming there are8 timeslots available for GPRStraffic.

0.1 2 8 2 During circuit switched busy


47/163

GPRS PLANNING GUIDE

% hour at least 2 switchabletimeslot will be occasionallyused by the circuit switch sideof the network in an attempt toprovide the best possible GOS -assumed to be on the order of

0.1%.

2% 3 8 2 During the circuit switchedbusy hour, 2 of the switchabletimeslots will be occasionallyused by the circuit switch sideof the network in an attempt toprovide the 2% GOS.

0.1%

3 10 4 During the circuit switchedbusy hour, 4 of the switchabletimeslots will be occasionally

used by the circuit switch sideof the network in an attempt toprovide the best possible GOS -assumed to be on the order of0.1%.

2% 4 9 3

0.1%

4 12 6

2% 5 10 4

0.1%

5 14 8 All of the switchabletimeslots will be occasionallyused to satisfy the 0.1% GOS.

2% 6 12 6

0.1%

6 15 9 There are not enoughswitchable timeslots to reach0.1% GOS.

2% 7 13 7

0.1%


2% 8 14 8 All of the switchabletimeslots will be occasionally


48/163

GPRS PLANNING GUIDE

used to satisfy the 2% GOS.

0.1%


2% 9 15 9 There are not enoughswitchable timeslots to reach2% GOS

0.1%


10.5. RECOMMENDATION

The following recommendation is offered when using switchable timeslots.It is important to determine the GOS objectives for circuit switched traffic andQoS objectives for GPRS traffic prior to selecting the number of switchabletimeslots to deploy.

During the circuit switched busy hour, potentially all switchable timeslotswill be occasionally used by the circuit switched calls. The circuit switchedtimeslot allocation mechanism will continue to assign switchable timeslots ascircuit switched timeslots as the circuit switched traffic continues to increase.

Therefore, if there is a minimum capacity requirement for GPRS services,then the Network Planner should plan the GPRS carrier with enough reservedtimeslots in order to handle the expected GPRS data traffic. This will ensure

that there is a minimum guaranteed network capacity for the GPRS datatraffic during the circuit switched busy hour.

During the circuit switched off busy hours, the switchable timeslots couldbe considered as available for use by the GPRS network. Therefore, in thecircuit switched off busy hours potentially all switchable timeslots could beavailable for the GPRS network traffic. The BSS call statistics should beinspected to determine the actual use of the switchable timeslots by thecircuit switched services.

The circuit switched busy hour and the GPRS busy hour should bemonitored to see if they overlap when switchable timeslots are in use. If the

busy hours do overlap, then an adjustment may need to be made to thenumber ofreservedtimeslots allocated to the GPRS portion of the network inorder to guarantee a minimum GPRS quality of service as measured by GPRSthroughput and delay. Furthermore, one or more circuit switched carriersmay need to be added to the cell being planned or re-planned so that theswitchable timeslots are not required in order to offer the desired circuitswitched Grade of Service.


49/163

GPRS PLANNING GUIDE

In conclusion, assume switchable timeslots are occasionally unavailablefor GPRS traffic during the circuit switched portion of the networks busyhour. Provision enough reservedtimeslots for GPRS traffic during the circuitswitched busy hour to meet the desired minimum GPRS Quality of Serviceobjectives, as measured by GPRS data throughput.

The following step-wise process is proposed when determining how bestto allocated GPRS carrier timeslots:

Assumptions:

1. A GPRS carrier can be added to a cell in addition to circuitswitched carriers.

2. A circuit switched carrier can be used to provide the controlchannels (BCCH/CCCH/SDCCH) on one or more timeslots as needed.

3. The number of circuit switched timeslots are determined as part

of the BSS planning effort prior to the GPRS planning effort.

4. When the "Concentration at BTS" feature is enabled, a sufficientpool of reserved backing resources will be provisioned in support of thenumber of reserved GPRS timeslots in order to meet the GPRS Qosobjectives.

Step 1:

Determine how many reservedGPRS timeslots are needed on a per cell

basis in order to satisfy a GPRS throughput QoS. The GPRS reservedtimeslotsshould equal the sum of the Active and Standby timeslots that are allocatedto a carrier.

Step 2:

If there are any timeslots left on the GPRS carrier after Step 1, considerusing them as switchable timeslots. The use of switchable timeslots canpotentially offer increased capacity to both the GPRS and circuit switchedtraffic if the traffic is staggered in time.

Step 3:

If there is a need to use some timeslots on the GPRS carrier to satisfy thecircuit switched GOS objectives and the timeslot requirement overlaps withthe number ofreservedGPRS timeslots, then consider adding another circuitswitched carrier to the cell.

Step 4:


50/163

GPRS PLANNING GUIDE

After deploying the GPRS carrier, review the network statistics listed inSection 14 on a continuous basis in order to determine if the reservedGPRStimeslots, switchable GPRS timeslots, and circuit switched timeslots are trulyserving the GOS and QoS objectives. As previously discussed, the use ofswitchable timeslots can offer network capacity advantages to both circuitswitched traffic and GPRS traffic as long as the demand for these timeslots is

staggered in time.


51/163

GPRS PLANNING GUIDE

11. A IR INTERFACE PLANNING PROCESS

The air interface planning process uses the range of values listed inTable4. If network values are not available at the time a network is planned, typicalor recommended values are provided where appropriate. The "Minimum

Values" are given for the maximum capacity of a minimum system and the"Typical Values" are used as standard model parameters.

11.1. AIR INTERFACE PLANNING INPUTS

Table 4

Air Interface Planning Inputs

Variable Minimum

Value

Typical

Value

Maximum

Value

Assumptions /

Variable Use

CS rate ratio,

CS-1/CS-2

Approx. 0%

10% 100 % CS rate ratio is determined bthe Cell Plan, mean TBF siand use of Acknowledge modRefer to Cell Plan tables Tab5,Table 6, andTable 7.

V.42 biscompressionratio

1 2.5 4 A ratio of 1 means there is nocompression and a ratio of 4 isthe theoretical maximum, whicis most likely never realized.

Most users will see acompression advantage in therange of 2-to-3 over the airinterface between the MS andthe SGSN. The compressionration is used in Equation 3.

BLER 0 10% 100% The Block Error Rate is largelydetermined by the cell RF Planand the typical value is anaverage rate. There areseparate BLERs for CS1 and CS

rates that are RF Plan specific.

FTD 0.7second

3 secondsfor a 3Kbyte file,subject tonetworkload andmultislot

File sizedependent

This is the File Transit Delayobjective measured in secondsfrom the Um interface to the Ginterface. The minimum delay the approximate delay for a RLblock of 23 bytes or less whichis the minimum system limit


52/163

GPRS PLANNING GUIDE

operation. with only one user on thesystem. The FTD value isdetermined by Equation 4.

The number ofGPRS Time

Slots per Cell

0 Networkdependent

8 This number can represereserved and/or switchab

timeslots as explained startinwith Figure 4 through Figu11.

Number ofActive GPRS

Time Slots perPCU withredundancy

30 Networkdependent

240 This is the number of timeslotssimultaneously in use with N+redundancy. This number isused to calculate the number oPRP and PICP boards to equip athe PCU using the rules inTab10.

Number ofGPRS usersmonitored atthe PCU withredundancy

90 Networkdependent

720 This is the number of mobilthat can be monitored addition to the mobiles actuausing timeslots. This valureflects N+1 redundancy. Thnumber reflects the coveragcapability of the PCU.

Number ofActive GPRS

Time Slots perPCU without

redundancy

30 Networkdependent

270 This is the number of timeslotssimultaneously in use withoutN+1 redundancy. This numberis used to calculate the numbe

of PRP and PICP boards to equat the PCU using the rules in

Table 10.

Number ofGPRS usersmonitored atthe PCU withoutredundancy

90 Networkdependent

810 This is the number of mobilesthat can be monitored inaddition to the mobiles actuallusing timeslots without N+1redundancy. This numberreflects the coverage capabilitof the PCU.

Mean LLC PDUPacket Size(Bytes)

20 435 1,580 This parameter is used indetermining the cell andsubscriber throughputcapacities.

Data Traffic /Subscriber

0 98Kbytes/Hou

Nomaximumlimit other

This parameter is the expecteGPRS load of a subscriber. Thfigure should include the SM


53/163

GPRS PLANNING GUIDE

(Peak) r than whatthenetwork isprovisioned tosupport.

traffic carried as GPRS data.

Total number ofGPRS Pages perattachedsubscriber

0 0.6 Nomaximumlimit otherthan whatthenetwork isprovisioned tosupport.

This effects the signaling traffload over the SGSN-to-PCU(Ginterface, the PCU-to-BSinterface(GSL) and the BSC BTS interface(RSL). The GPRpaging traffic must be added the circuit switched signalintraffic at the BSC in order determine the total signalintraffic between the BSC anreporting BTSs. This paramet

will also be used to determinthe GPRS load on the CCCH.

Number of datatransfers perhour persubscriber

0 112

(based on 2435 ByteLLC PDUsper TBFand 98Kbyte peruser per

busy hour)

Nomaximumlimit otherthan whatthenetwork isprovisioned tosupport

This number will be used determine the provisioning the control channels (CCCprovisioning).

Number ofBSC'ssupportingGPRS per OMC-R serving area

1 Networkdependent

64 This will establish how manPCUs are required per OMCserving area. The size of tPCU will be determined from thGPRS subscriber profile.

(provision 1 PCU per BSC)

EquipmentRedundancy

(BSS PCU &GSN)

No Ye

Documents

GPRS Planning Guide