www.huawei.comCopyright 2009 Huawei Technologies Co., Ltd. All
rights reserved.GPRS Principles1Copyright 2009 Huawei Technologies
Co., Ltd. All rights reserved. Page1Foreword GPRS principle is the
basic part of the whole GPRS systemand the succeeding products
learning. This slide will help us to understand the GPRS
systemnetworking and wireless subsystem etc.2Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page2Objectives Upon
completion of this course, you will be able to: Know the GPRS
system structure Describe the GPRS important interfaces Understand
the GPRS channel structures Master the GPRS relevant
numbering3Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page3Contents1. GPRS System Overview2. GPRS
Architecture3. GPRS Network Interfaces & Protocols4. GPRS
Wireless Subsystem5. GPRS Location Area4Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page4Circuit Switch
(CS)CSFCSCS CSCSABCDEGHIJKL5Copyright 2009 Huawei Technologies Co.,
Ltd. All rights reserved. Page5Packet Switch (PS)PSPSPS1 2 31 2 31
3221 3221 31 2 31 2 3PSPSPSPSACB D6Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page6GSM Development
EvolutionGSM 9.6 Kb/sGPRS21.4 Kb/sEGPRS59.2 Kb/sUMTS 384 Kb/s2 G2.5
G2.75 G3 GHSCSD14.4 Kb/sECSD38.8 Kb/sCSPSEDGE7Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page7What is GPRS and
EDGE? Abbreviation of General Packet Radio Service. GPRS is an
end-to-end packet switching technologyprovided on the basis of GSM
technology. It has much interactive services with the existing
GSMcircuit switching system. GPRS supports wireless access rate of
up to 171.2Kbps. EDGE (Enhanced Data Rates for GSM Evolution) EGPRS
(Enhanced GPRS) EGPRS supports wireless access rate of up to
473.6Kbps. ECSD (Enhanced CSD, Enhanced HSCSD-High Speed
CircuitSwitched Data)GPRS is the abbreviation of General Packet
Radio Service.GPRS network introduces packet switching functional
entities in the GSM networkto implement data transmission in the
packet mode.GPRS can be regarded as the service expansion based on
the GSM network forsupporting mobile subscribers access the
Internet of other packet data networks viapacket data mobile
terminal. Making full use of the existing GSM
network,smallinvestment and quick rewarding,all of these benefit to
protect the existinginvestment and obtain maximum benefits for the
operators.8Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page8GPRS&EDGE Coding RateGMSK
8PSK9.0513.415.621.48.811.214.817.622.429.644.854.459.20.0010.0020.0030.0040.0050.0060.00CS-1
CS-3 CS-4 MCS-1 MCS-2 MCS-3 MCS-4 MCS-5 MCS-6 MCS-7 MCS-8
MCS-9KbpsGPRSEGPRSCS-29Copyright 2009 Huawei Technologies Co., Ltd.
All rights reserved. Page9Adjustments to GSM NetworkBSS CS
CoreNetworkAPS CoreNetworkPCUBSS NSSGbPbGs10Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page10Most Popular GPRS
Applications E-mail Web Browsing Information Services Moving Images
Still Images Remote LAN Access File Transfer Job DespatchTraffic
InformationSport ReportWeather ForecastStock
MarketPublicInformationServiceEmailWeb BrowsingStill ImagesFile
TransferMoving BankLive NewsPersonalInformationService11Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved.
Page11Advantages and Disadvantages ofGPRS Advantages Share resource
with GSM High resource utilization Fast transmission rate Always on
line Short access time Disadvantages Slower data rates in practice
than anticipated in theory Suboptimal modulation
technique12Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page12Contents1. GPRS System Overview2. GPRS
Architecture3. GPRS Network Interfaces & Protocols4. GPRS
Wireless Subsystem5. GPRS Location Area13Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page13CS & PS Logic
StructureHLRAUCGPRSRegisterMSC/VLRBSC AbisDCCSGMSC PSTNBTSBSSCNEAPS
GsSGSNGGSNGbGnGcGrGiInternetG-Abis PbPCUTRAU14Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page14GfGn
GiGcGpGsMSC/VLRGrSGSNGdSMS-GMSCSMS-IWMSCGGSNEIRSGSNGnGPRSBackboneATM/DDN/ISDN/Ethernet,
etcCN-PSGGSNGiCGGPRS System
StructureGbSS7HLRGaIntranet/InternetFirewallRADIUSWAP GatewayOther
PLMNBTSBSCBSSAbisPCUGbBTSBSS BSCAbisPCUX.25DNS BGMSMS15Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved. Page15GPRS
MS Class A The MS is attached to both GPRS and other GSM services
and theMS supports simultaneous operation of GPRS and other
GSMservices. Class B The MS is attached on GPRS network and GSM
networksimultaneously but not enabling circuit switching and packet
switchingservices at the same time. services are selected
automatically. Class C The MS is attached to either GPRS or other
GSM services. Alternateuse only. services are selected manually or
default selected service.16Copyright 2009 Huawei Technologies Co.,
Ltd. All rights reserved. Page16Functions of PCU (Packet Control
Unit) Packet wireless resource management function (RLC/MACprotocol
function) Wireless resource management functions of GPRS BSS
Circuit paging coordination G-Abis interface processing function
Function related with GPRS BTS17Copyright 2009 Huawei Technologies
Co., Ltd. All rights reserved. Page17Functions of PCU (Packet
Control Unit) Pb interface processing function LAPD link between
BSC and PCU Layer-3 signaling between BSC and PCU Gb interface
processing function Data packet relay on wireless interface and Gb
interface Mobility management (cell updating procedure) Downlink
traffic control (wireless QoS guarantee)Provides physical and
logical data interface out of the BSS for packet datatrafficLLC
layer PDU segmentation/reassembly of RLC blocksPacket data transfer
schedulingARQ functionsRadio channel management function18Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved.
Page18Functions of SGSN (Serving GPRSSupport Node) Packet routing
MS Session management Authentication and Ciphering Mobility
management Billing information collection19Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page19Functions of GGSN
(GatewayGPRS Support Node) Interface between GPRS backbone and
external PDNs. PDP Conversion and context management IP address
assignment management Packet routing to/from SGSNs Billing
information collection20Copyright 2009 Huawei Technologies Co.,
Ltd. All rights reserved. Page20Functions of CG (ChargingGateway)
Real-time collection of GPRS bills Temporary storage and buffering
of GPRS bills Pre-processing of GPRS bills Sending GPRS bills to
the billing center21Copyright 2009 Huawei Technologies Co., Ltd.
All rights reserved. Page21Functions of MSC/VLR When Gs interface
is installed, MSC/VLR can support Establishment and maintenance of
the association betweenSGSN and MSC/VLR. GPRS combined mobility
management procedure. Combined IMSI/GPRS attachment/detachment.
Combined location area/routing area updating. Circuit paging
coordination function. The wireless resource usage can be greatly
improved.22Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page22Functions of HLR/AUC Saving and updating GPRS
subscriber subscription data User authentication Providing
location/routing information and processingneeded in mobility
management and routing, for example: Saving and updating user
service SGSN number and address GPRS user location deletion
indication Whether MS is reachable. Subscriber tracing
(optional)23Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page23Functions of SMS-GMSC/SMS-IWMSC The SMS-GMSC and
SMS-IWMSC are connected to the SGSNvia the Gd interface to enable
GPRS MSs to send and receiveSMs over GPRS radio channels. After Gd
interface is installed, short messages can be sent viaGPRS, which
reduces the occupation on SDCCH and cuts downthe influence on voice
services by SMS services. The operator can select to send SMS via
MSC or SGSN.MS SGSN SMS-IWMSCSMS-GMSCSMS GdSMS-IWMSC(Interworking
MSC For Short Message Service):A function of an MSC capable
ofreceiving a short message from within the PLMN and submitting it
to the recipient SC.For example:The MSC forwards the SM to the
SMS-IWMSC, which is responsible for processingSMs submitted by the
MS.SMS-IWMSC:The SMS Interworking MSC acts as an interface between
the PLMN and a ShortMessage Service Centre (SC) to allow short
messages to be submitted from Mobile Stations to
theSC.SMS-GMSC(Gateway MSC For Short Message Service):A function of
an MSC capable of receivinga short message from an SC,
interrogating an HLR for routing information and SMS info,
anddelivering the short message to the VMSC of the recipient MSFor
example:The SMS system submitsthe message transfer request to the
SMS-GMSC, which is responsible for processing delivered
SMs.SMS-GMSC:The SMS Gateway MSC (SMS-GMSC) acts as an interface
between a Short MessageService Centre and the PLMN, to allow short
messages to be delivered to mobile stations from theService Centre
(SC)24Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page24Functions of BG (Border Gateway) BG enables the
following protocols necessary for interworking betweenoperators
Security protocol: IPSec and firewall are recommended Routing
protocol: BGP is recommended Billing protocol: determined by the
operators with negotiation; BG might beneeded in collecting billing
information It is normally based on routers It can be combined with
GGSN in physical. BG does not exclusively belong to the GPRS
network.GpPLMN AGSN RBGRBG GSNPLMN BIPsec (IP security) is a
standardized framework for securing Internet Protocol
(IP)communications by encrypting and/or authenticating each IP
packet in a data stream.A protocol for exchanging routing
information between gateway host s (each withits own router ) in a
network of autonomous system s. BGP is often the protocolused
between gateway hosts on the Internet.25Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page25Functions of DNS
(Domain Name System) The following two types of DNSs may be adopted
in the GPRSnetwork: The DNS between the GGSN and external networks
The DNS on the GPRS backbone network. Provides two types
offunctions: a. Resolve the GGSN IP address based on the Access
Point Name (APN)in the process of the PDP context activation; b.
Resolve original SGSN IP address based on the original routing area
No.in the process of the update of inter-SGSN routing area. DNS
does not exclusivelybelong to the GPRS network.GPRSSGSN BackboneDNS
ServerSGSNDNSDomain Name SystemThe following two types of DNSs may
be adopted in the GPRS network:The DNS between the GGSN and
external networks: Implements resolution of thedomain name of
external network, and functions as the ordinary DNS on the
Internet.The DNS on the GPRS backbone network. Provides two types
of functions:a. Resolve the GGSN IP address based on the Access
Point Name (APN) inthe process of the PDP context activation;b.
Resolve original SGSN IP address based on the original routing area
No.in the process of the update of inter-SGSN routing area. The DNS
is not aproprietary entity of the GPRS network.26Copyright 2009
Huawei Technologies Co., Ltd. All rights reserved. Page26Functions
of RADIUS Server (RemoteAuthentication Dial In User Service Server)
It is a protocol used by Remote Access Server's for
userAuthentication. The RADIUS server stores the authentication
andauthorization information of subscribers. It also performs
subscriber identity authentication in thecase of non-transparent
access. RADIUS Server does not exclusively belong to the
GPRSnetwork.27Copyright 2009 Huawei Technologies Co., Ltd. All
rights reserved. Page27Contents1. GPRS System Overview2. GPRS
Architecture3. GPRS Network Interfaces & Protocols4. GPRS
Wireless Subsystem5. GPRS Location Area28Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page28Contents3. GPRS
Network Interfaces & Protocols3.1 Interface and Protocol
Stack3.2 Um Interface3.3 G-abis/Pb Interface3.4 Gb Interface3.5 Gs
Interface29Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page29Network interface typesGPRS
backbonenetworkSSGGSSNNSSGGSSNNGn GGGGSSNNIP interfaceSS7
interfaceBSS MSCSMSGMSCUm APDP
network(IP/X.25)GiTEMTMSHLRGsGrGdGcGb30Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page30Interface in GPRS
NetworkUm The interface between MS and GPRS network sideGf The
interface between the SGSN and EIR (optional).Gs The interface
between the SGSN and MSC/VLR (optional).Gr The interface between
the SGSN and HLR.Gp The interface between GSNs of different
PLMNs.Gn The interface between SGSNs and between SGSN and GGSN in
the PLMN.Gi The reference point between the GPRS and external
packet dataThe interface between SMS and GMSCGd The interface
between SMS-IWMSC and SGSNGc The interface between the GGSN and HLR
(optional).Gb The interface between the SGSN and BSS.The reference
point between the Mobile Terminal (MT) (for example,
mobilephone)and the Terminal Equipment (TE) (for example, the
portable computer).RInterface Description31Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page31Data transmission
plane MAC: Media Access Control RLC: Radio Link Control LLC:
Logical Link Control BSSGP: BSS GPRS Protocol SNDCP: Sub-Network
Dependency Convergence Protocol GTP: GPRS Tunneling
ProtocolApplicationIP/X.25 IP/X.25 IP/X.25SNDCP GTPLLC LLC UDP/TCP
UDP/TCPRLC BSSGP BSSGP IP IPMAC MAC NetworkServiceNetworkService L2
L2L2
(MAC)PhysicalLayerPhysicalLayerPhysicalLayerPhysicalLayerPhysicalLayerPhysicalLayerPhysicalLayerMS
BSS SGSN GGSNrelayrelaySNDCP GTPUm Gb Gn GiRLCThe Relay function
provides buffering and parameter mapping between the RLC/MAC and
the BSSGP. For example, on theuplink the RLC/MAC shall provide a
TLLI. The Relay function shall then make it available to
BSSGP.32Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page32MS-SGSN signaling plane GMM: GPRS Mobility
Management SM: Session ManagementMS BSS SGSNBSSGPGMM/SMLLCRLCMACGSM
RFGMM/SMLLCBSSGPL1bisUm GbNetworkServiceRLCMACGSM RF
L1bisNetworkServiceRreellaayyUm interface:Physical layer: wireless
coding/decoding, channel multiplexing and mapping, wireless
linkcontrol and wireless measurementRLC/MAC: wireless interface
media access and link control functionLLC: providing a reliable
logic link between MS and SGSN for data transmission. LLCprotocol
can support both acknowledged mode and unacknowledged mode. It
supports both encryption anddecryption modesSNDCP: Layer-3
transmission protocol. As the transition between the network layer
and thesubnet layer, it implements segmentation/assembling and
compression/decompression on IP/X.25 subscriber dataGMM/SM: Layer-3
signaling protocolGb interface:L1bis: physical transmission layer
based on E1 or T1NS: based on FR; used to transmit BSSGP PDU of the
upper layerBSSGP: On the transmission platform, this protocol is
used to provide aconnectionless link between BSS and SGSN for
unacknowledged data transmission; on thesignaling platform, it is
used to transmit QoS and routing information related with
thewireless section; it is also used to process paging requests and
implement traffic control ondata transmission33Copyright 2009
Huawei Technologies Co., Ltd. All rights reserved. Page33Contents3.
GPRS Network Interfaces & Protocols3.1 Interface and Protocol
Stack3.2 Um Interface3.3 G-abis/Pb Interface3.4 Gb Interface3.5 Gs
Interface34Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page34Protocol Layer of Um Interface GMM (GPRS Mobility
Management): operates in the signallingplane of GPRS supports
mobility management functionality. SM (Session Management):
processes procedure that GPRSMS connects to the external data
network. SNDCP (Subnetwork Dependent Convergence
Protocol):Multiplexing of several PDPs, compression /
decompressionand Segmentation of user data. LLC (Logical Link
Control ): This layer provides a highlyreliable ciphered logical
link between an MS and its SGSN. RLC:Segmentation and re-assembly
between LLC PDUs andRLC blocks. MAC: defines the procedures that
enable multiple mobilestations to share a common transmission
medium.LLCRLCMACRFPhysical LinkSNDCPSMSGMM/SMGMM (GPRS Mobility
Management)This protocol that operates in the signalling plane of
GPRS supportsmobility management functionality such as GPRS attach,
GPRS detach,security, routing area update, location update,
roaming, authentication, andselection of encryption algorithms.SM
(Session Management)It is the processing procedure that GPRS MS
connects to the external datanetwork. The main function is to
support the processing of PDP mobilescenario.Logical Link Control
(LLC): This layer provides a highly reliable cipheredlogical link
between an MS and its SGSN.LLC includes functions forthe provision
of one or more logical link connections discriminated betweenby
means of a DLCI.sequence control, to maintain the sequential order
of frames across a logicallink connection.detection of
transmission, format and operational errors on a logical
linkconnection.recovery from detected transmission, format, and
operational errors.notification of unrecoverable errors.flow
control.ciphering.35Copyright 2009 Huawei Technologies Co., Ltd.
All rights reserved. Page35MM StateIDLEGMM context is not
established; MS is not reachable.MS can implement data
transmission.GMM context is established; MS can receive paging
butcannot implement data transmission. The MS performs MM
procedures to provide the network with the actualselected cell.
SGSN performs the MM on cell level.READYSTANDBY The location
information in the SGSN MM context contains only the GPRS RAI.
Pages for data or signalling information transfers may be received.
It is alsopossible to receive pages for the CS services via the
SGSN. Data receptionand transmission are not possible in this
state. Data transmission to and from the mobile subscriber as well
as the paging ofthe subscriber are not possibleThe Mobility
Management (MM) activities related to a GPRS subscriber
arecharacterised by one of three different MM states.36Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved. Page36MM
State ModelIDLE READY STANDBYIDLE READY STANDBYMM State Modelof
MSMM State Modelof SGSNGPRS AttachGPRS DetachREADY timer expiry
orPDU transmissionPDU receptionImplicit Detach or Cancel
LocationGPRS AttachForce to STANDBYREADY timer expiry orForce to
STANDBY orAbnormal RLC conditionGPRS Detach orCancel
Location37Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page37RLC/MAC Block GenerationRLC/MAC blockSubscriber
data SNDCP head LLC head LLC FCS RLC/MAC headLLC frameSubscriber IP
packet (N-PDU)SNDCP PDU(SN-PDU)Network LayerSNDCP LayerLLC
LayerRLC/MAC Layer38Copyright 2009 Huawei Technologies Co., Ltd.
All rights reserved. Page38Physical Channel The same as in GSM The
same frequency The modulation mode The same TDMA frame definition
The same burst pulse definition The differences between GPRS and
GSM The Multi-frame structure The channel coding
ApplicationIP/X25SNDCPLLCRLC RLC BSSGPMAC MAC
FramerelayPhysicalLayerPhysicalLayerPhysicalLayerMS
BSSRelay39Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page39Packet Logic Channels The specific type of PDCH
(except PRACH) is determined byRLC/MAC head and RLC/MAC control
message type.TCHBCCHPCH, RACH, AGCH,NCHPacket service
channelPACCHPacket Logic ChannelPacket control channelPBCCHPPCH
PRACH PAGCHPCCCH PDCCHPDTCH/U PDTCH/D PNCHPTCCH/U
PTCCH/DSACCH40Copyright 2009 Huawei Technologies Co., Ltd. All
rights reserved. Page40Channel Abbreviation Packet Data Traffic
CHannel Uplink - PDTCH/U Packet Data Traffic CHannel Downlink -
PDTCH/D Packet Broadcast Control CHannel - PBCCH Packet Common
Control CHannel - PCCCH Packet Dedicated Control Channel - PDCCH
Packet Paging CHannel - PPCH Packet Random Access CHannel - PRACH
Packet Access Grant CHannel - PAGCH Packet Notification CHannel -
PNCH Packet Associated Control CHannel - PACCH Packet Timing
advance Control CHannel Uplink - PTCCH/U Packet Timing advance
Control CHannel Downlink -PTCCH/D41Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page41PDTCH (Packet
Data Traffic CHannel) All packet data traffic channels
areuni-directional. Uplink (PDTCH/U) for a mobileoriginated packet
transfer. Downlink (PDTCH/D) for a mobileterminated packet
transfer.Packet service channelPDTCH/U PDTCH/D42Copyright 2009
Huawei Technologies Co., Ltd. All rights reserved. Page42PBCCH
(Packet Broadcast ControlCHannel) The PBCCH broadcasts
parametersused by the MS to access the network forpacket
transmission operation. The PBCCH also carries the
informationtransmitted via the BCCH to allow circuitswitching
operation. The MS in GPRS attached mode monitorsthe PBCCH only, if
PBCCH is available,otherwise, the BCCH shall be used tobroadcast
information for packet operation. The existence of the PBCCH in the
cell isindicated on the BCCH via SI13.Packet control
channelPBCCH43Copyright 2009 Huawei Technologies Co., Ltd. All
rights reserved. Page43PCCCH (Packet Common ControlCHannel) PPCH
Downlink only, used to page MS. PRACH Uplink only, used to request
allocation of one orseveral PDTCH/Us or PDTCH/Ds. PAGCH Downlink
only, used to allocate one or severalPDTCHs. PNCH Downlink only,
used to notify MS of PTM-M call. If no PCCCH is allocated, the
information forpacket switching operation is transmitted on
theCCCH. If a PCCCH is allocated, it may transmitinformation for
circuit switching operation.PPCH PRACH PAGCHPCCCHPNCH44Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved. Page44PDCCH
(Packet Dedicated ControlChannels) PACCH Bi-directional, used to
transmit the packetsignaling in data transmission. PTCCH/U Used to
transmit random access bursts toallow estimation of the timing
advance forone MS in packet transfer mode. PTCCH/D Used to transmit
timing advance updates forseveral MS. One PTCCH/D is paired
withseveral PTCCH/U's.PACCHPDCCHPTCCH/U PTCCH/D45Copyright 2009
Huawei Technologies Co., Ltd. All rights reserved.
Page45Combinations of Packet LogicChannelMode 3:
PDTCH+PACCH+PTCCHMode 1: PBCCH+PCCCH+PDTCH+PACCH+PTCCHMode 2:
PCCCH+PDTCH+PACCH+PTCCHIn case of small GPRS traffic, GPRSand
circuit services share the sameBCCH and CCCH in the cell. In
thiscase, only combination mode 3 isneeded in the cell.With the
increase of traffic, thepacket public channel should beconfigured
in the cell. Channelcombination mode 1 and mode 2should be
adopted.Mode 4: PBCCH+PCCCH(PCCCH=PPCH+PRACH+PAGCH+PNCH46Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved.
Page46Packet Wireless ChannelConfigurations Reason of adopting
static PDCH To enable that GPRS MS is constantly online in the
cell. To ensure certain QoS of GPRS services. Reason of adopting
dynamic PDCH GPRS and GSM share wireless resources. Wireless
resources should be adopted in priority; on the other hand,QoS of
voice services should be ensured. In a cell, the percentage of
packet switching services and thepercentage of circuit switching
services are constantly changing. Dynamic PDCH is not visible for
voice services.47Copyright 2009 Huawei Technologies Co., Ltd. All
rights reserved. Page47Packet Wireless ChannelConfigurations
General principles The cell should be configured with static PDCH
to enable MS tobe normally attached on GPRS network as well as
certain QoS ofGPRS services. Dynamic PDCH should be configured
according to the GPRStraffic forecast, which should be adjusted as
TCH or PDCH usablein the operation process according to the cell
traffic status. Circuit switching services can seize the channel
used by GPRSservices.48Copyright 2009 Huawei Technologies Co., Ltd.
All rights reserved. Page48Mapping of Packet Logic Channel A radio
block is a 4-normal-burst sequence that carries aRLC/MAC PDU
(Protocol Data Unit).I = Idle frameT = Frame used for PTCCHB0 ~ B11
= Radio blocks0 25 51B0 B1 B2 T B3 B4 B5 I B6 B7 B8 T B9 B10 B11
I456 bits0 1 2 3 4 5 6 71 TDMA frame0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 749Copyright 2009 Huawei Technologies Co., Ltd. All
rights reserved. Page49Mapping of Packet Logic Channel5143567012 B0
B1 B2 T B3 B4 B5 I B6 B7 B8 T B9 B10 B11 I0 50BCCHPDCHTCHS B B B B
CC C C F SCCC C C CC C F S CC CCC C CC F S C C C C CCCC F S C C CCC
C CC IT T T T T T T T T T T T S T T T T T T T T T T T T IF2512
2550Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page50Transmission Principle of Data Packeton Um
InterfaceSubscriber data SNDCP head LLC head RLC/MAC headSubscriber
IP packetLLC FCSSNDCP PDULLC PDURLC/MAC blockPhysical layerB0 B1 B2
T B3 B4 B5 I B6 B7 B8 T B9 B10 B11 INBNBNBNB51Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page51Allocation of
Wireless PacketResources Wireless resource allocation and wireless
transmission adopt the wireless block(BLOCK) as the basic unit.
Each PDCH can be used by several MSs; each MS can use multiple
PDCHs at thesame time.B1 B2 B3 B4 B5 B6 B7 B8 B9 B10B11B0B1 B2 B3
B4 B5 B6 B7 B8 B9 B10B11B0B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11MS2
MS3TS 0TS 1TS 2MS152Copyright 2009 Huawei Technologies Co., Ltd.
All rights reserved. Page52Basic Conceptions about Radio Block
USF(Uplink State Flag) is sent in all downlinkRLC/MAC blocks and
indicates the owner or useof the next uplink Radio block on the
sametimeslot. The USF field is three bits in lengthB11 B10 B9 B8 B7
B6 B5 B4 B3 B2 B1 B0 T I T IULDLUSF=1 USF=1 USF=1 USF=2 USF=2 USF=3
USF=3 USF=3 USF=3 USF=4 USF=4 USF=4 T I T
IUSF=1USF=2USF=3USF=4MS1MS2MS3MS4USF=1 B0 I The USF field is three
bits in length and eight different USF values canbe assigned,
except on PCCCH, where the value '111' (USF=FREE)indicates that the
corresponding uplink Radio block contains PRACH.53Copyright 2009
Huawei Technologies Co., Ltd. All rights reserved. Page53Basic
Conceptions about Radio Block TBF (Temporary Block Flow) A
Temporary Block Flow (TBF) is a physical connection used by thetwo
RR entitiesthe RR entity of the MS and that of the BSS tosupport
the unidirectional transfer of LLC PDUs on packet dataphysical
channels. A TBF is temporary and is maintained only for the
duration of the datatransfer. TFI (Temporary Flow Identity) Each
TBF is assigned a Temporary Flow Identity (TFI) by the network. The
TFI field is five bits in length.The same TFI value may be used
concurrently for TBFs in opposite directions. TheTFI is assigned in
a resource assignment message that precedes the transfer of
LLCframes belonging to one TBF to/from the MS. The same TFI is
included in everyRLC header belonging to a particular TBF as well
as in the control messagesassociated to the LLC frame transfer
(e.g. acknowledgements) in order to addressthe peer RLC
entities.54Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page54Contents4. GPRS Wireless Subsystem4.1 Packet
Channels4.2 Medium Access Modes4.3 MS Multi-TS Ability4.4 Power
Control4.5 Network Control Modes55Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page55Medium Access
Modes Uplink resource allocation mode Dynamic allocation (supported
by all MSs and all networks) The mobile station detecting an
assigned USF value for each assigned PDCH andblock or group of four
blocks that it is allowed to transmit on that PDCH. Fixed
allocation (supported by all MSs and all networks) Fixed bit
mapping is adopted to determine the allocated blocks in the
allocation periodwithout an assigned USF. Extended dynamic
allocation (optional for the network) The mobile station detecting
an assigned USF value for any assigned PDCH allowingthe mobile
station to transmit on that PDCH and all higher numbered
assignedPDCHs in the same block or group of four blocks. Downlink
resource allocation mode Dynamic allocation and fixed
allocation.Three medium access modes are supported:- Dynamic
Allocation characterised by that the mobile station detecting an
assigned USFvalue for each assigned PDCH and block or group of four
blocks that it is allowed to transmit on thatPDCH;- Extended
Dynamic Allocation characterised by the mobile station detecting an
assignedUSF value for any assigned PDCH allowing the mobile station
to transmit on that PDCH and allhigher numbered assigned PDCHs in
the same block or group of four blocks- Fixed Allocation
characterised by fixed allocation of radio blocks and PDCHs in
theassignment message without an assigned USF. Fixed Allocation may
operate in half duplex mode,characterised by that downlink and
uplink TBF are not active at the same time. Half duplex mode isonly
applicable for multislot classes 19 to 29.Either the Dynamic
Allocation medium access mode or Fixed Allocation medium access
mode shallbe supported by mobile stations and all networks that
support GPRS. The support of ExtendedDynamic Allocation is optional
for the network.The Dynamic Allocation and Fixed Allocation modes
shall be supported in all mobile stations. Thesupport of Extended
Dynamic Allocation is mandatory for mobile stations of multislot
classes 22, 24,25 and 27. The support of Extended Dynamic
Allocation for mobile stations of all other multislotclasses are
optional and shall be indicated in the MS Radio Access
Capability.In the case of a downlink transfer, the term medium
access mode refers to the measurement timescheduling, for the MS to
perform neighbour cell power measurements56Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page56Contents4. GPRS
Wireless Subsystem4.1 Packet Channels4.2 Medium Access Modes4.3 MS
Multi-TS Ability4.4 Power Control4.5 Network Control
Modes57Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page57MS Multi-TS Ability Concept of MS multi-TS ability
Types Type 1: Non-simultaneous TRX Type 2: Simultaneous TRX the
multi-TS ability level is 1-29; the bigger the level, the stronger
themulti-TS ability. 1~12 (Type 1),up to 4 timeslots in any
direction 13~18 (Type 2),ranges between 3~8 timeslots 19~29 (Type
1) BSS allocates resources according to the MS multi-TS
ability,requested QoS and current resource
configuration.58Copyright 2009 Huawei Technologies Co., Ltd. All
rights reserved. Page58Contents4. GPRS Wireless Subsystem4.1 Packet
Channels4.2 Medium Access Modes4.3 MS Multi-TS Ability4.4 Power
Control4.5 Network Control Modes59Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page59Power Control
Power control can improve the spectrum usage and systemcapacity as
well as reduce MS power consumption. As there is no continuous
bi-directional connection in the packetdata transmission process,
GPRS power control is verycomplicated. Uplink power control
includes open-loop and close-loop powercontrol. About downlink
power control, there is no specific definition inprotocol. It lies
on the BTS and its algorithm needs informationabout downlink, so
downlink power control needs MS sendschannel quality reports to
BTS.60Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page60Contents4. GPRS Wireless Subsystem4.1 Packet
Channels4.2 Medium Access Modes4.3 MS Multi-TS Ability4.4 Power
Control4.5 Network Control Modes61Copyright 2009 Huawei
Technologies Co., Ltd. All rights reserved. Page61Network Control
Modes During the network controlled cell re-selection, the
networkmay request measurement reports from the MS and controlits
cell re-selection. Hence, three types of mode are definedas
follows: NC0: Normal MS controls NC1: MS control with measurement
reports NC2: Network control The network subsystem must support NC0
and shouldgradually support NC1 and NC2.During the network
controlled cell re-selection, the network may requestmeasurement
reports from the MS and control its cell re-selection. Hence,
threetypes of mode are defined as follows:NC0: Normal MS controls.
The MS shall perform autonomous cell re-selection.NC1: MS control
with measurement reports. The MS shall send measurementreports to
the network. The MS shall perform autonomous cell re-selection.NC2:
Network control. The MS shall send measurement reports to the
network. TheMS shall not perform autonomous cell re-selection.The
network subsystem must support NC0 and should gradually support NC1
andNC2.62Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page62Network Control ModesMS NC0 NC1NC2The MS shall
perform autonomous cell re-selectionMSThe MS shall perform
autonomous cell re-selectionThe MS shall sendmeasurement reportsto
the networkMS BTSMRCell re-selectioncommandThe MS shall notperform
autonomous cellre-selection63Copyright 2009 Huawei Technologies
Co., Ltd. All rights reserved. Page63Contents1. GPRS System
Overview2. GPRS Architecture3. GPRS Network Interfaces &
Protocols4. GPRS Wireless Subsystem5. GPRS Location Area64Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved.
Page64Relationship among
LocationAreasCELLCELLCELLCELLRA1RA2CELLCELLRA3CELLCELLCELLSGSN1SGSN2BSC1BSC2BSC3LA1
LA265Copyright 2009 Huawei Technologies Co., Ltd. All rights
reserved. Page65Location Area IdentificationMCC MNC LACLAI
(Location Area Identification) MCCMobile Country Code, it consists
of 3 digits. For example: TheMCC of China is "460" MNCMobile
Network Code, it consists of 2 digits. For example: TheMNC of China
Mobile is "00" LACLocation Area Code, it is a two bytes hex code.
The value 0000and FFFF is invalid For example: 460008C9066Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved. Page66RAI
Routing area is the sub-set of the location area. In special cases,
the twoareas are equal The division of the routing area is related
with traffic distribution andSGSN processing abilityLocation Area
IdentificationMCC MNC LAC RACRouting Area Identification67Copyright
2009 Huawei Technologies Co., Ltd. All rights reserved. Page67CGI
CI (Cell Identity): This code uses two bytes hex code to identify
the radiocells within a LAI. RAC is only unique when presented
together with LAI. CI is only unique when presented together with
LAI or RAI. CGI = MCC+MNC+LAC+{RAC}+CILocation Area
IdentificationMCC MNC LAC CICGIRACRouting Area
Identification68Copyright 2009 Huawei Technologies Co., Ltd. All
rights reserved. Page68CGIRelationship among location areas LAI
MCC+ MNC+ LACLAI RAI MCC+ MNC+ LAC+RAC CGI /CellID MCC+ MNC+
LAC+{RAC}+CIRAI69Copyright 2009 Huawei Technologies Co., Ltd. All
rights reserved. Page69Summary GPRS System Overview GPRS
Architecture GPRS Network Interfaces & Protocols GPRS Wireless
Subsystem GPRS Location Area70Thank
youwww.huawei.com71www.huawei.comCopyright 2010 Huawei Technologies
Co., Ltd. All rights reserved.GPRS EDGE
MobileManagementAlgorithm72Copyright 2010 Huawei Technologies Co.,
Ltd. All rights reserved. Page1Foreword GPRS Mobility Management is
a GPRS signalingprotocol that handles mobility issues such as
roaming,authentication and selection of encryption algorithms.It is
important to enable the network to keep track thecurrent location
of the MS in order for the paging to beperformed smoothly. With the
proper setting of theGMM parameters, we can shorten the access
delay ofthe MS.73Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page2References GBSS8.1 BSC6000 Feature
Description74Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page3Objectives Upon completion of this course,
you will be able to: Understand the GPRS Mobility Management
procedure Familiar with the GMM state model Understand the cell
reselection algorithm Recognize the cell update and routing area
update flow Realize the GMM related parameters75Copyright 2010
Huawei Technologies Co., Ltd. All rights reserved. Page4Contents1.
Overview of GPRS Mobile Management2. Location Update3. GPRS Cell
Selection & Reselection76Copyright 2010 Huawei Technologies
Co., Ltd. All rights reserved. Page5Overview for GPRS Mobile
Management The main purpose of the mobility management is to keep
trackof the users current location. Thus, the paging can
beperformed. MS perform cell selection and reselection when it
movesaround the coverage area. It also sends the location
updatemessage to the SGSN so that the network can be alwaysaware of
the MSs current location. There are 3 states exist in the GPRS
mobility managementand different location information is available
in each state(please see the following figure MM State).77Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved. Page6GMM
StateIDLE GMM context is not established; MS is not reachable. MS
can implement data transmission. GMM context is established; MS can
receive paging butcannot implement data transmission. The MS
performs MM procedures to provide the network with the
actualselected cell. SGSN performs the MM on cell
level.READYSTANDBY The location information in the SGSN MM context
contains only the GPRS RAI. Pages for data or signalling
information transfers may be received. It is alsopossible to
receive pages for the CS services via the SGSN. Data receptionand
transmission are not possible in this state. Data transmission to
and from the mobile subscriber as well as the paging ofthe
subscriber are not possible.78Copyright 2010 Huawei Technologies
Co., Ltd. All rights reserved. Page7GMM State ModelIDLE READY
STANDBYIDLE READY STANDBYMM State Modelof MSMM State Modelof
SGSNGPRS AttachGPRS DetachREADY timer expiry orPDU transmissionPDU
receptionImplicit Detach or Cancel LocationGPRS AttachForce to
STANDBYREADY timer expiry orForce to STANDBY orAbnormal RLC
conditionGPRS Detach orCancel Location By performing GPRS attach,
the MS gets into READY state and if the MS does nottransmit any
packet for a long period of time until the READY timer is expired,
the MS willget into STANDBY state. It is possible to transmit data
only if the MS is in READY state, thus the MS in STANDBYstate can
switch back to the READY state, if a PDU transmission occurs and in
the sameway, at READY state if the GPRS detach is performed, the MS
will be back into IDLEstate and all PDP context will be deleted. In
STANDBY state, the MS sends the location update message seldom, so
its location isnot known exactly and the paging is necessary for
every downlonk packet, resulting in adelivery delay. In READY
state, the MS updates its location frequently. Consequently the MSs
locationis known precisely and no paging delay during delivery
downlonk packet. Howeverm thisconsumes much more the uplink radio
capacity and battery of the MS.79Copyright 2010 Huawei Technologies
Co., Ltd. All rights reserved. Page8GMM State vs Location
Information During GMM IDLE state, MS is detached from GPRS. ThusMS
can not receive paging nor data transmission. During GMM STANDBY
state, MS is attached to the GPRSnetwork and it will perform
routing area update (RAU), MScontrolledcell reselection and monitor
paging. It only reportRA changes. During GMM READY state/ packet
transfer mode, MS willperform both routing area update (RAU) and
cell update (bothMS-controlled and Network-controlled cell
reselection). Itreport the cell changes and RA changes.80Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved.
Page9Contents1. Overview of GPRS Mobile Management2. Location
Update2.1Relationship between Cell, Routing Area & Location
Area2.2LAI, RAI, CGI2.3Signaling flow for Cell Update, RA Update
& LA Update3. GPRS Cell Selection & Reselection81Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved.
Page10Relationship among Location
AreasCELLCELLCELLCELLRA1RA2CELLCELLRA3CELLCELLCELLSGSN1SGSN2BSC1BSC2BSC3LA1
LA2 When MS across Location Area border, LAU & RAU is necessary
When MS moves within same LA and across Routing Area boarder, RAU
is necessary When MS moves within the same LA and RA, cell update
may be needed may beneeded. It depends on the current state of the
MS.a) READY state: MS updates the location every cell change. This
strategy ensures thatthe accurate location of the MS is always
known and packet data can be delivered fasteras no paging procedure
is necessary. However the MS battery is drained more anduplink
radio capacity is wasted for cell updates.b) STANDBY state: MS
updates the location only when the MS moves to a new routingarea
(RA). In this strategy, when data packet is sent to the MS, paging
is required inorder to find out the current location of the MS.
Thus, uplink capacity will be wasted forpaging response and every
downlink packet requires paging of the mobile delay.82Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved.
Page11CGIRelationship among Location Areas LAI MCC+ MNC+ LACLAI RAI
MCC+ MNC+ LAC+RAC CGI /CellID MCC+ MNC+ LAC+{RAC}+CIRAI83Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved.
Page12Contents1. Overview of GPRS Mobile Management2. Location
Update2.1Relationship between Cell, Routing Area & Location
Area2.2LAI, RAI, CGI2.3Signaling flow for Cell Update, RA Update
& LA Update3. GPRS Cell Selection & Reselection84Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved.
Page13Location Area IdentificationMCC MNC LACLAI (Location Area
Identification) MCCMobile Country Code, it consists of 3 digits.
For example: TheMCC of China is "460" MNCMobile Network Code, it
consists of 2 digits. For example: TheMNC of China Mobile is "00"
LACLocation Area Code, it is a two bytes hex code. The value
0000and FFFF is invalid For example: 460008C9085Copyright 2010
Huawei Technologies Co., Ltd. All rights reserved. Page14RAI
(Routing Area Identification) Routing area is the sub-set of the
location area. In special cases, the twoareas are equal. The
division of the routing area is related with traffic distribution
andSGSN processing abilityLocation Area IdentificationMCC MNC LAC
RACRouting Area Identification86Copyright 2010 Huawei Technologies
Co., Ltd. All rights reserved. Page15CGI (Cell Global Identity) CI
(Cell Identity): This code uses two bytes hex code to identify the
radiocells within a LAI. RAC is only unique when presented together
with LAI. CI is only unique when presented together with LAI or
RAI. CGI = MCC+MNC+LAC+{RAC}+CILocation Area IdentificationMCC MNC
LAC CICGIRACRouting Area Identification87Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page16Contents1.
Overview of GPRS Mobile Management2. Location Update2.1Relationship
between Cell, Routing Area & Location Area2.2LAI, RAI,
CGI2.3Signaling flow for Cell Update, RA Update & LA Update3.
GPRS Cell Selection & Reselection88Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page17Cell Update
FlowMS Old Cell SGSNUplink LLC-PDU[MS ID]SGSN received andrecorded
the cell updateNew CellSGSN send thesubsequence serviceto MS
through thenew cellPDU (CGI) in BSSGP-PDURLC Radio Block1. When the
MS moves from one cell to another within the same RA and LA,
cellupdate procedure will happen during the READY state.2. During
the READY state/ packet transfer state, MS will keep monitor its
currentlocation and cell reselection will happen. When MS discover
another better cellaccording to its own measurement. The MS stops
listening to the old cell andstart to read the necessary SYSINFO in
the new cell.3. MS make an access in the new cell and send a cell
update to the SGSN(transparent to the PCU).4. SGSN will obtain the
cell update (cell change information) from the uplink LLCPDUand
record the cell update information and discovers that there
wasalready an ongoing downlink packet transfer.5. SGSN will then
sends a Flush message to the respective PCU. The Flushmessage
contains the addresses to both the old and new cell as well as the
MSidentity.6. The PCU check whether it is responsible for the new
cell. In that case all thebuffered frames/ the subsequence service
will be moved to a queue towards thenew cell. The PCU assign new
resources to the MS in the new cell andtransmission is restarted.7.
If the PCU is not responsible for the new cell, it will delete all
the framesdestined to the MS ang leave the retransmission to higher
layers.89Copyright 2010 Huawei Technologies Co., Ltd. All rights
reserved. Page18Intra-SGSN Routing Area Update FlowMS BSS
SGSNROUTING AREA UPDATE REQUEST ROUTING AREA UPDATE REQUEST[Old
RAI, old P-TMSI, update type] [Old RAI, old P-TMSI, update type,
new CI]SECURITY FUNCTIONS (optional)ROUTING AREA UPDATE
ACCEPT[P-TMSI, P-TMSI signature]ROUTING AREA UPDATE
COMPLETE[P-TMSI] optional]1. When MS moves to new RA, it sends RA
update request including the RAI ofthe old RA to its assigned SGSN.
When the message arrives at the BSS, theBSS adds the CI of the new
cell. Based on the RAI and CI data, SGSN canderived the new RAI.
Intra-SGSN routing area update: The MS has moved to an RA, assigned
to thesame SGSN as the old RA. In this case, the SGSN knows already
all necessaryuser profile, and can assign a new packet temporary
mobile subscriber identity(P-TMSI) to the user without the need to
inform other network elements. Security function: authentication
and ciphering/encrpytion90Copyright 2010 Huawei Technologies Co.,
Ltd. All rights reserved. Page19Inter-SGSN Routing Area Update
FlowMS BSSNewSGSNROUTING AREA UPDATE REQUEST[Old RAI, old P-TMSI,
update type]OldSGSN GGSN HLRPDP CTT REQ[GGSN address]PDP CTT ACKPDP
CONTEXT UPDATEPDP CONTEXT UPDATE ACKDATABASE UPDATEINSERT SUBCRIBER
DATAROUTING AREA UPDATE COMPLETEROUTING AREA UPDATE ACCEPT
Inter-SGSN routing area update: In this case, the MS has moved to
an RA,assigned to a different SGSN, thus, the new SGSN does not
have the userprofile of the MS. The new SGSN contacts the old SGSN
and requests the PDPcontext of the user. After receiving the PDP
context of the user, the new SGSN informs the involvednetwork
elements, GGSN about the new PDP context of the user HLR about the
users new SGSN HLR cancels the MS information context in the old
SGSN and loads thesubscriber data to the new SGSN. New SGSN
acknowledges to the MS The old SGSN is requested to transmit the
undelivered data to the new SGSN.91Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page20Contents1.
Overview of GPRS Mobile Management2. Location Update3. GPRS Cell
Selection & Reselection3.1Cell Reselection
Algorithm3.2Parameter for Cell Reselection3.3Type of Cell
Reselection92Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page21GPRS Cell Reselection Algorithm If no PBCCH
exists, the GPRS cell selection &reselection is basically the
same as GSM cellselection & reselection (C1, C2):C2 = C1 + CRO
TO*H(PT-T) when PT=/31C2 = C1 CRO when PT=31C1 = RLA_C
RxLev_Acc_Min Max((MS_TXPWR_MAX_CCCH P), 0)1. C1 = RLA_C -
RxLev_Access_Min - Max((MS_TxPwr_MAX_CCH - P), 0)2. C2 = C1 + CRO -
TO * H(PT-T) when PT=/313. C2 = C1 - CRO when PT= 3193Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved. Page22GPRS
Cell Reselection Algorithm If no PBCCH exists, the GPRS cell
selection & reselection isbasically the same as GSM cell
selection & reselection (C1, C2)excepts for the following
conditions:a) When MS in STANDBY mode, Cell reselection within the
same RA/LA:C2(nei) > C2 (serving) for t>5s Cell reselection
between different RA/LA:C2(nei) > C2 (serving) + CRH for
t>5sb) When MS in READY mode, Cell reselection within the same
RA/LA:C2(nei) > C2 (serving) + CRH for t>5s Cell reselection
between different RA/LA:C2(nei) > C2 (serving) + CRH for
t>5s1. C1 = RLA_C - RxLev_Access_Min - Max((MS_TxPwr_MAX_CCH -
P), 0)2. C2 = C1 + CRO - TO * H(PT-T) when PT=/313. C2 = C1 - CRO
when PT= 3194Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page23Cell Reselection in Standby ModeRA 1RA 2Cell
ACell BCell CAC2>BC2 CC2>BC2CRH95Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page24Cell Reselection
in Ready ModeBC2>AC2CRHRA 1Cell ACell B96Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page25GPRS Cell
Reselection Algorithm If PBCCH exists, new cell selection &
reselection algorithm(C31, C32) is applicable:C31(s) = RLA_P(s)
HCS_THR(s) (Serving cell)C31(n) = RLA_P(n) HCS_THR(n)
GPRS_TO(n)*H(GPRS_PENALTY_TIME-T)*L(n) (Neighbor cell)C31 = signal
threshold criterionRLA_P = actual received level of the GPRS
cellHCS_THR = signal level threshold of cell reselection of HCS
GPRSGPRS_TO = GPRS temporary offsetL = 0; when PRIORITY_CLASS (s) =
PRIORITY_CLASS (n)L = 1; when PRIORITY_CLASS (s) =/ PRIORITY_CLASS
(n) C31 = signal threshold criterion/ signal level threshold
criterion of HCS and is used tojudge whether to adopt preference
cell reselection HCS_THR = Hierarchical Cell Structure signal level
threshold of cell reselection of HCSGPRS. It is broadcast on PBCCH
of the service cell. RLA_P = Received level of the GPRS cell TO =
Temporary offset given to the neighbor when the neighbor
cellsPRIORITY_CLASS is different from the PRIORITY_CLASS of the
serving cell97Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page26GPRS Cell Reselection Algorithm If PBCCH
exists, new cell selection & reselection algorithm(C31, C32) is
applicable:C32(s) = C1 (Serving cell)C32(n) = C1 +
GPRS_RESELECT_OFF GPRS_TO*H(GPRS_PENALTY_TIME T) * (1-L) (Neighbor
cell)H(X GPRS_PENALTY_TIMEH(X>0) = 1; T < GPRS_PENALTY_TIMEL
= 0; when PRIORITY_CLASS (s) = PRIORITY_CLASS (n)L = 1; when
PRIORITY_CLASS (s) =/ PRIORITY_CLASS (n)C1 = RxLev
GPRS_Acc_Level_Min Max( (GPRS_MS_TXPWR_MAX_CCH P), 0) C32 =
Perfection of C2 applied to GSM. It applies the offset and the
delay value to thecell reselection which needs execution of cell
update program or route update program.When the PBCCH channel does
not exist in the service cell, the MS will execute cellreselection
according to the C2 algorithm. T = timer with initial value =0.
When a cell is recorded by the MS into the 6 strongest cell,the
counter corresponding to this cell, T will begin to count at a
precision of one TDMAframe (4.62ms). When this cell is removed from
the 6 strongest cell list, the timer is reset. GPRS TO = temporary
offset, which counts from the counter T. T to the98Copyright 2010
Huawei Technologies Co., Ltd. All rights reserved. Page27GPRS Cell
Reselection Algorithm In additional, it is necessary to consider
the routing area forthe serving cell and adjacent cell: When MS in
STANDBY mode, and within the same RAC32(n) = C32(n) When MS in
READY mode, and within the same RAC32(n) = C32(n) -
CELL_RESELECT_HYSTERESIS When MS in READY or STANDBY mode, with
different RAC32(n) = C32(n) - RA_RESELECT_HYSTERESIS C32(n) = Final
calculated/ actual value of the C32 criterion after consider the
routingarea of the serving cell and neighbor cell.99Copyright 2010
Huawei Technologies Co., Ltd. All rights reserved. Page28Cell
Reselection Trigger Condition Cell reselection triggering
condition:Random access attempt is unsuccessfulafter
MAX_RETRANSRandom access attempt isunsuccessful after
MAX_RETRANS45321With C1, C2 criterion With C1, C31, C32 criterionC1
< 0 C1 < 0Downlink signaling failure Downlink signaling
failureBetter cell with the highest C32 among:(a) Highest
PRIORITY_CLASS, C31>=0(b) All cell, if no cell fulfils C31
criterionBetter neighbor cell detected:Same RA: C2(n) > C2(s)
for t>5sDif RA: C2(n) > C2(s)+CRH for t>5Serving cell is
barred Serving cell is barred100Copyright 2010 Huawei Technologies
Co., Ltd. All rights reserved. Page29Contents1. Overview of GPRS
Mobile Management2. Location Update3. GPRS Cell Selection &
Reselection3.1Cell Reselection Algorithm3.2Parameter for Cell
Reselection3.3Type of Cell Reselection101Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page30Network Control
Mode Cell Attribute -> GPRS Attributes Parameter Name: Network
Control Mode Description:In the cell reselection required by the
network, the network requests the MS to sendmeasurement reports to
control its cell reselection. There are three network controlmodes.
nc0: Normal MS control. The MS performs automatic cell
reselection.nc1: MScontrol with measurement reports. The MS sends
measurement reports to the networkand performs automatic cell
reselection.nc2: Network control. The MS sendsmeasurement reports
to the network but does not perform automatic cell reselection. GUI
Value Range: [nc0,nc1,nc2] Default Value: nc0102Copyright 2010
Huawei Technologies Co., Ltd. All rights reserved. Page31Parameter
for GPRS Cell Reselection Network Control Mode (NCO)Controlled
byYes Only Ready network Network ControlNC2 ModeControlled byYes
Only Ready MS MS Control withNC1 M.R ModeControlled byMSReady
&No Standby Normal MSNC0 Control ModeCellSelectionModeMS
modeWhether theMS send theM.RMode Definition NC0: MS performs
autonomous cell reselection without sending measurement reports
tothe network. NC1: MS performs autonomous cell reselection and
sends measurement reports tonetwork. NC2: Network controls cell
reselection and MS sends measurement reports to
thenetwork.103Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page32Support NC2 Cell Attributes ->Other
Attributes Parameter Name: Support NC2 Description: This parameter
specifies whether the cell supports the Network Control 2 (NC2)
function.In NC2, the MS reports the measurement report of the
reference cell and neighbor cellsto the BSC. The BSC controls cell
reselection (including normal reselections and
loadbasedreselections) of the MS. GUI Value Range: [No,Yes] Default
Value: No104Copyright 2010 Huawei Technologies Co., Ltd. All rights
reserved. Page33NC2 Support in External Neighbour Cell BSC6000
-> Configure2G External Cell Parameter Name: NC2 Support in
External Neighbour Cell Description:This parameter specifies
whether the GSM external cell supports NC2. GUI Value Range: [Not
Support,Support] Default Value: Not Support105Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page34Parameter for
GPRS Cell Reselection Cell Attributes -> GPRS Attributes ->
Advanced -> PsOther Parameters Parameter Name: Cell Urgent
Reselection Allowed Description: This parameter specifies whether
enabling thecritical cell reselection algorithm is allowed. GUI
Value Range: [Forbid,Permit] Default Value: Permit Parameter Name:
Cell Load Reselection Allowed Description: This parameter specifies
whether enabling thecell load-based reselection algorithm is
allowed. GUI Value Range: [Forbid,Permit] Default Value: Permit
Parameter Name: Cell Normal Reselection Allowed Description: This
parameter specifies whether enabling thenormal cell reselection
algorithm is allowed. GUI Value Range: [Forbid,Permit] Default
Value: Permit106Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page35Support NACC Cell Attributes ->Other
Attributes Parameter Name: Support NACC Description:This parameter
specifies whether the cell support the Network Assisted Cell
Change(NACC) function.In network control mode NC0, NC1, or NC2,
when the MS is in thepacket transmission mode, the network informs
the MS of the system information aboutneighbor cells in advance.
Therefore, the cell reselection of the MS is accelerated. GUI Value
Range: [No,Yes] Default Value: No107Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page36Contents1.
Overview of GPRS Mobile Management2. Location Update3. GPRS Cell
Selection & Reselection3.1Cell Reselection
Algorithm3.2Parameter for Cell Reselection3.3Type of Cell
Reselection108Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page37GPRS Cell Reselection Type There are 3 type
of cell reselections: MS controlled cell reselection Network
controlled cell reselection Network assisted cell
reselection109Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page38MS-Controlled Cell Reselection MS-Controlled
Cell Reselection MS periodically measures the RX levels of all the
BCCH carriers of theserving cell and its neighboring cells. With no
PBCCH configured, MS calculates C2 value. With PBCCH configures, MS
calculates C31/C32 value. Based on the calculated value, MS decided
whether to reselect a newserving cell. Also call as autonomous cell
reselection. Parameter setting: Support NC0/ NC1 to YES110Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved.
Page39Network-Controlled Cell Reselection Network-Controlled Cell
Reselection MS periodically sends measurement reports to the BSC
based on theparameters in the SYSINFO broadcast in the cell. Based
on the measurement reports and neighboring cell load, BSCsends a
cell change command to the MS if all conditions are met, leadingthe
MS to a suitable cell. Parameter setting: Support NC2 to
YES111Copyright 2010 Huawei Technologies Co., Ltd. All rights
reserved. Page40Network-Controlled Cell Reselection(NC2)MS
BSSPACKET MEASUREMENT REPORTPACKET CELL CHANGE ORDERPACKET CELL
CHANGE FAILURE[P-TMSI] optional]PACKET NEIGHBOR CELL DATANC2 Cell
Reselection AlgorithmPACKET ENHANCED MEASUREMENT REPORT1. MS in the
GMM Ready mode state periodically sends PACKETMEASUREMETN REPORT to
the BSC.2. After receive the MR, NSC process the MR. According to
the NC2 cellreselection algorithm, BSC determines whether to
perform cell reselection.3. If BSC determines to initiate a cell
reselection, it send PACKET CELL CHANGEORDER to MS to instruct MS
to reselect the target cell. If NACC support,PACKET NEIGHBOR CELL
DATA containing SYSINFO will be sent before thePACKET CELL CHANGE
ORDER so that the reselection can be accelerated.4. If cell
reselection fails, MS sends PACKET CELL CHANGE FAILURE messageto
BSC. After receive this message, BSC subtracts CELL PENALTY
LEVELfrom the RxLev of the target cell.112Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page41NC2 Cell
Reselection Algorithm The NC2 cell reselection algorithm follows
the prioritysequence in descending order of: Urgent reselection
algorithm Load reselection algorithm Normal reselection algorithm
Urgent reselection is based on the receive quality of the radio
link on the Um interface. IfBER increases, the possible reason is
that the signal level is too low or there isinterference on the
channel. In the network, load in some cells are heavy and some are
light. To balance the load inthese cells, load reselection is
performed. In load reselection procedure, MS in heavy-loaded cell
are directed to light-loaded cell.MS in neighbouring cell should
not be reselected to the heavy-loaded cell. Normal reselection is
based on Receive Level. When urgent reselection an loadreselection
are not met, normal reseelction is started to handover MS to a
neighboringcell with higher signal strength if the RxLev (serving
cell) < [Min Access Level Threshold]113Copyright 2010 Huawei
Technologies Co., Ltd. All rights reserved. Page42NC2 Cell
Reselection AlgorithmYes YesYes Yes YesYes YesNoNo NoNoNo
NoNoYesNoMeasure RxLev & RxQualMS in the MR[Cell
UrgentReselection Allowed]?MS RxQualdeterioration ratio >[MS Rx
Qual WorsenThreshold][Cell Load ReselectAllowed]?[Cell Normal
ReselectAllowed]?Channel multiplexingrate>[Load ReselectStart
Thres]Any MS RxLev load reselection -> normal reselection Each
type of reselection have different trigger condition.114Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved. Page43NC2
Cell Reselection AlgorithmYes Yes YesYesNoNo
NoNoRxLev>MAX(RxLev(s),[Min_Acc_Level_Thres])+[Cell Reselect
Hyst] ANDnon-congestion stateEc/No>[PS FDD EcNoQuality Thres]
orRSCP>[PS FDD RSCPQuality Thres]RSCP>[PS FDD RSCPQuality
Thres]Cell reselection successful?Trigger urgent cell reselection
and select cellwith the highest priority in cell list.[Cell Penalty
Level] given totarget cell with [cell PenaltyLast Time]For GSM Cell
For FDD Cell For TDD CellContinueEndEnd The priority of the target
cell is determined by receive level and the
characteristicsinformation such as cell type, cell priority,
support for EDGE, and load status. Different cell type will need to
fulfill the specified condition to be the candidate cell. When cell
reselection fails, penalty is given to the target cell. If penalty
time within [CellPenalty Last Time (s)], [Cell Penalty Level] is
subtracted from the receive level of thetarget cell.115Copyright
2010 Huawei Technologies Co., Ltd. All rights reserved. Page44NC2
Cell Reselection AlgorithmServing cell isGSM cell, targetcell is
UTRANDifferent BSC,both GSM cellSame BSCServing cell&Target
cellpositionIntra-BSC Highest priority in the cell
list.ConditionCellReselectionTypeFor FDD cell : Ec/No>[PS FDD
EcNo Quality Thres]or RSCP>[PS FDD RSCP Quality Thres]For TDD
cell: RSCP>[PS TDD RSCP Quality Thres]GSM toUTRANRxLev (Ext nei)
= RxLev (n) MAX(2, [CellReselection Hyst/2])Inter-BSC Each NC2 cell
reselection algorithm contains three NC2cell reselection type:
Intra-BSC cell reselection:Serving cell and target cell are
controlled by same BSC. The selected target cellis the one that has
highest priority in the cell list. Inter-BSC cell
reselection:Serving cell and target are in different BSC and both
is GSM cell. The priority forthe external neighbouring cell is
lower. Thus,RxLev (Ext nei) = RxLev (n) external cell reselection
offsetRxLev (Ext nei) = RxLev (n) MAX(2, [Cell Reselection Hyst/2])
GSM to UTRAN cell reselection:Serving cell is GSM cell and target
cell is UTRAN cell. The 3G MR and the2G/3G cell priority strategy
should be processed during the cell reselection.For FDD cell:
Ec/No>[PS FDD EcNo Quality Thres] or RSCP>[PS FDDRSCP Quality
Thres]For TDD cell: RSCP>[PS TDD RSCP Quality Thres][2G/3G Cell
Reselection Strategy] : Preference for 2G cell, Preference for 3G
cell116Copyright 2010 Huawei Technologies Co., Ltd. All rights
reserved. Page45Network-Assisted Cell Reselection Network-Assisted
Cell Reselection It is also known as NACC, Network Assisted Cell
Change. MS originates a cell change notification (CCN) procedure,
and the BSCsends the system information (SYSINFO) about the
neighboring cell tothe MS before the cell reselection. NACC
accelerates the cell reselection and shortens the servicedisruption
time during cell reselection. Parameter setting: Support NC0/ NC1/
NC2 to YES Support NACC to YES117Copyright 2010 Huawei Technologies
Co., Ltd. All rights reserved. Page46Network Assisted Cell Change
(NACC) Purposes: MS is able to request BSC to send the target cells
SYSINFOduring the cell reselection. Advantages: According to the
SYSINFO, MS accelerates the packet serviceaccess in the target
cell. Reduce the period of packet service disruption during a
cellreselection .118Copyright 2010 Huawei Technologies Co., Ltd.
All rights reserved. Page47Network Assisted Cell Change (NACC)Cell
A Cell BReceive Systeminformation of cell Bbefore
reselection119Copyright 2010 Huawei Technologies Co., Ltd. All
rights reserved. Page48Network Assisted Cell Change (NACC) MS can
initiate an NACC procedure only when autonomous cellreselection is
triggered: In NC0/ NC1 mode and packet transfer mode: C1