1、GPRS - EDGE,吴伟民 电子与信息工程系 ,2,GPRS - EDGEOverview GPRS Services,Network Architecture Um Interface (MS-Bss) 52- Multitrame Logical Channels Physical Channel GPRS Stack Layer SNDCP LLC,GPRS en mode Idle GPRS Network mode Classes des mobiles Multislot Class Session Management Evolution to EDGE Modulation
2、s GPRS vs EDGE EDGE: RLC/MAC,RLC / MAC TBF,3,GPRS: Overview,What is GPRS,General,But only applicable to specific services,Packet,Obviously,Radio,But much more,Service,But rather a transmission method,4,GPRS: Overview,Circuit vs. Packet,Circuit,Packet,5,GPRS: Overview,GPRS vs. non GPRS,Differences be
3、tween GPRS and GSM,Warranty on traffic,Warranty on delay vs. Best effort,Charging on time vs. charging on volume,Radio resource sharing,Dedicated channels vs. Shared channels,Transmission mode in the network,Circuit 64 kbps vs. IP network User rate up to 160 kbps,6,GPRS: Overview,Circuit vs. Packet,
4、Service (point to point protocol),GSM allows both circuit and packet service GPRS allows only packet service,Switch mode in the network,In MSC, circuit switch at 64 kbps In GPRS, datagram switch,Radio path transmission,GSM use a resource during the complete call (circuit) But data are always in pack
5、et format (burst),7,GPRS: Overview,Shared Channels,The equivalent of a TCH is allocated to 16 (max) multiplexed flows,Possible to allocate several such resources to one user (multi-slot),Release through timer,Independent handling of direction,WEB application traffic is not symmetricalLimitation thro
6、ugh GSM symmetrical scheme,8,GPRS: Overview Location Area Code is relevant to LA (Location Area) inside a PLMN. Routing Area Code is relevant to RA (Routing Area) inside a LA.,PLMN ALAC ACell CRAC A,RAC B,LAC B,PLMN B,Cell A,Cell B,9,IP,GPRS: OverviewTCP/IPIP: Internet Protocol,To route datagram (32
7、 bits address) throughinterconnected networksegmentationTCP: Transmission Control ProtocolPoint to point transport,TCP,UDP,Numbering and acknowledge of datamultiplexingUDP: User Datagram ProtocolMore simple than TCP,Local networkprotocol(GPRS),No acknowledgement Used for WAP,10,GPRS Network Architec
8、ture,GPRS network equipment,Radio sub-system,CCU: Channel Codec Unit,Part of the BTS mainly handling the physical layer,PCU: Packet Control Unit,Handles RLC and MAC layers,Switches,SGSN: Serving GPRS Support Node GGSN: Gateway GPRS Support Node,11,Um Interface (MS-BSS)MM Sub-LayerLLC,RR-SAP,GMMRR-SA
9、P,GRR-SAPRR Management,Non -RR,PD,RR,RR,Upper Layer PDUsRLC/MAC,SAPI 0,SAPI 3,PBCCH,PCCCH,PACCH,PDTCH,BCCH,RACH PCH SDCCHAGCH,SACCH,FACCH,SDCCH,SACCH,Data Link Layer (signalling L2)PDCHPHYSICAL LINK LAYER,12,52 Multi-TrameTDMA Frame: Same as GSM technologyNew format : Multi-frame 52 (PDCH : Packet D
10、ata Channel) 1 Block ( 4 frames in continue),B 0,B 1,B 2,X,B 3,B 4,B 5,X,B 6,B 7,B 8,X,B 9,B 10,B 11,X,52 multiframe (duration 240 ms)Bn : Blocks X : Idle frames,13,Logical ChannelsPBCCH : Packet Broadcast Common ChannelPCCCH : Packet Common Control ChannelPAGCH : Packet Access Grant Channel,PPCH :,
11、Packet Paging Channel,PRACH : Packet Random Access ChannelPDTCH : Packet Data Transfer ChannelPACCH : Packet Associated Control ChannelPTCCH : Packet Timing advance Control Channel,14,Logical Channels, PBCCH + PCCCH + PDTCH + PACCH + PTCCH + PRACH, PCCCH + PDTCH + PACCH + PTCCH, PDTCH + PACCH + PTCC
12、H,15,Logical Channels,Shared Channels Logical channels,PDTCH (Packet Data Traffic Channel) and PACCH (Packet Associated Control Channel),To convey user and signalling data,Multiplexed between 16 (or less) users Unidirectional (UL or DL),PTCCH (Packet Timing advance Control Channel),To manage timing
13、advance,Divided into 16 bi-directional channels Fixed allocation,16,Logical Channels, Common Logical Channels (optional), PBCCH: trnasmits network description (Packet,System Information Type x), PCCCH, PPCH: equivalent to PCH, PAGCH: equivalent to AGCH, PRACH: equivalent to RACH (up to 11 bits),17,P
14、hysical Channel,Shared Channels Physical channels,PDCH (Packet Data Channel) is a physical channelPDCH is based on one frequency and one timeslotLogical channels are mapped onto physical channelsPDCH is organized into blocks of 4 consecutive bursts,18,TBF : Temporary Block Flow,3GPP 44.060 Definitio
15、n:,A Temporary Block Flow (TBF) is aconnection used by the two RR entities to,support the unidirectional,transfer of upper layer PDUs on packet data,physical channels (PDCH),19,GPRS Stack LayersUser Plane GPRS: Application,Appli,Control Plane GPRS: Control L3,IP-X25SNDCPLLCRLCMACL1PDTCH TBF-User,PDT
16、CH TBF - Control,SM | GSMSGMMLLCRLCMACL1,Control Plane GPRSGRRRLCMACL1PBCCH / PCCCHPRACHPACCH /PTCCH,B 0,B 1,B 2,X,B 3,B 4,B 5,X,B 6,B 7,B 8,X,B 9,B 10,B 11,X,52 multiframe (duration 240 ms),20,GPRS User Plane,21,GPRS Control Plane,22,GPRS Control Plane,23,GPRS SNDCPOverviewMultiplexing of several P
17、DPsBetween MS and SGSN: NSAPISequencing warranty for each PDPAccess to LLC through several QoS profilesSegmentation / Re-assemblyCompressionIP headerData,MS: SNDCP,SGSN: SNDCP,24,GPRS MS IDENTITY,MS identities,IMSI: 8 bytes,Unique identity,Stored in the SIM card,P-TMSI (Packet Temporary Mobile Subsc
18、riber Identity): 4 bytes,Similar to TMSI,Used to avoid sending IMSI Allocated within a RA,TLLI (Temporary Logical Link Identity): 4 bytes,Used by RLC/MAC layers Derived from P-TMSI,P-TMSI signature: 3 bytes,Used to skip authentication procedure,25,GPRS MS IDENTITYTLLI: Temporary Logical Link Identif
19、ierAllocated by SGSNUsing P-TMSITLLI,LLC,LLE x: SAPIx LLE z: SAPI z,LLC,LLE x: SAPIx LLE z: SAPI z,LLE y: SAPI y,MS,LLE y: SAPI y,SGSN,DLCIx (Data Link Connection Identifier)TLLI+SAPI,26,GPRS MS IDENTITY,TLLI handling,GMM generates the TLLI,GMM sends the TLLI to RLC/MAC, LLC and L3 RR,Random TLLI,Us
20、ed in case no P-TMSI is available Identifier + Random bits,Foreign TLLI,Used in case P-TMSI is available but assigned in a different RA Identifier + Bits derived from the P-TMSI,Local TLLI,Used in case P-TMSI is available and assigned in this RA Identifier + Bits derived from the P-TMSI,27,GPRS LLCA
21、ddress Field,PD C/R X,X,SAPI,PD: Protolcole Discriminator, LLC= 0, Other = InvalidC/R = Command / Response,SAPI:,0001: GPRS Mobility Mgt: LLGMM 0010 : Tunnelling of Msg 2 :TOM2 0011 : User Data 3 : LL3 0101 : User Data 5 : LL5 0111 : SMS 1000 : Tunnelling of Msg 8 : TOM8 1001 : User Data 9 : LL9 101
22、1 : User Data 11: LL11,28,GPRS LLC3 Modes LLC,Protected ModeCRC-24bitsHeader + Data,Unprotected ModeCRC-24bitsHeader,Acknowledged ModeErr. FramesSGSN,TO M,S N D C P,G M M,S MS,T O M,S N D C P,G M M,S MS,LLC,LLC,RLCMACGSM RF,RLCMACGSM RF,BSSGPNetw. Serv.L1,BSSGPNetw. Serv.L1,MS,Um,BSS,Gb,29,1,1,1,1,0
23、,1,GPRS LLCControl FieldA Acknoledgement Request bitE Encryption function bit,8,7,6,5,4,3,2,1,Mn Unnumbured function bit,I format(I+S),0,A XN(S),X,N(S),N(R),N(R) Transmitter receive sequence nbrN(S) Transmitter send sequence number,N(R),S1,S2,N(U) Transmitter unconfirmed sequence,S format,1,0,A,XN(R
24、),X,N(R)S1,S2,number P/F Poll Bit when issued as CommandFinal Bit when issued as Response,UI formatU format,X X N(U)N(U) E PMP/F M4 M3 M2 M1,PM Protected Mode BitSn Supervisory function bitX Spare Bit,30,GPRS LLC,Control Field,80,7A,6X,5,4,3N(S),2,1,1,N(S),X,N(R),2,N(R),1,1,3,X,X,X,K,4,I frame,R(1)
25、R(2) R(3) R(4) R(5)R(6) R(7) R(8),SACK format,R(9) R(10)R(11)R(12)R(13) , R(16),R(253) R(254) R(255),X 36(max),1,0,A,X,X,N(R),1,N(R),1,1,2,S frame SACK format,R(1) R(2) R(3) R(4) R(5)R(6) R(7) R(8)R(9) R(10)R(11)R(12)R(13) R(16),R(253) R(254) R(255),X 34 (max),31,GPRS RLC/MACManagement of TBFs (Temp
26、orary Blocks Flows)Management of Logical ChannelsTBF has oneTFI,Unidirectionnal Identity allocated by networkCoding Scheme:, CS 1 CS 2 CS 3 CS 4,Block Size : 22 octets, 9 kbit/s Block Size : 32 octets, 13.4 kbits/s Block Size : 38 octets, 15.6 kbits/s Block Size : 52 octets, 21.4 kbits/s,CS1,User da
27、ta,Protection,CS2CS3CS4,32,GPRS RLC/MACTBFStands for Temporary Block Flow“Channel” allocated between the MS and the BSS to conveydataUnidirectional (Uplink or Downlink)Release through timer,MS,TBF1TBF1,TBF2,TBF2,BSS,33,GPRS RLC/MAC: Uplink TBF3 Modes for TBF Uplink AllocationStatic Allocation: a bit
28、map is sent to MS during,TBF establishment (1TS,1USF),Dynamic Allocation: MS sends 1 to 4Blocks on reception USF Flag from NetworkExtended Dynamic Allocation: MS sends 1 to 4Blocks on reception USF Flag from Network,But from 1 to N PDCHs, mandatory in MultiSlot2 Types of TBF Uplink Establishment1 ph
29、ase access2 phases access: mandatory for multi slot uplink transfer,34,GPRS RLC/MAC: Header of Uplink Data Block,Payload Type:, 00 RLC/MAC Data Block 01 RLC/MAC Control Block,Countdown Value,TFI: Temporary Flow Identity,BSN: Block Sequence Number, could be acknowledged by network,In sending Packet U
30、plink Ack/Nack message (including BSN(s) ACK-NACK),TLLI (optional),35,GPRS RLC/MAC: Header of Uplink Data BlockCountdown ProcedureUsed by the MS to announce the end of the TBFBS_CV_MAX (See SI13) indicates when the Countdown Procedure shallbe startedWhile remaining RLC/MAC blocks BS_CV_MAX,CV = 15,I
31、f remaining RLC/MAC blocks BS_CV_MAXCV = remaining RLC/MAC blocks - 1 Last RLC/MAC block sent with CV=0 Two RLC/MAC blocks sent with same CV if two UL timeslots are allocated to the MS Resource request is not possible during Countdown ProcedureNew RLC/MAC blocks New TBF,36,GPRS RLC/MAC: Header of Do
32、wnlink Data Block,Payload Type,S/P and RRBP: NW requires to MS for sending,Packet Control Acknowledgement control message,TFI: Temporary Flow Identity,BSN: Block Sequence Number, could be acknowledged by mobile,In sending Packet Downlink Ack/Nack message (including BSN(s) ACK-NACK),USF: Uplink State
33、 Flag,37,GPRS RLC/MAC: Header of Downlink Data Block,Uplink State Flag,Used to multiplex several users on the same PDCH,USF assigned to the MS during the assignment procedureUSF present in each DL RLC/MAC block,USF of the MS present within DL RLC/MAC block,The MS can send an UL RLC/MAC block at next
34、 occurrence,The MS sends one or four UL RLC/MAC block depending on USF GRANULARITY,USF is allocated on a timeslot basis,The MS needs to monitor every allocated timeslot,USF=7 reserved for PRACH,38,GPRS RLC/MAC: Header of Downlink Data BlockUplink State FlagMS1 is assigned USF1MS2 is assigned USF2DOW
35、NLINK,USF7,USF7,USF1,USF2,USF1,USF7,USF1,USF2,USF7,UPLINK,MS1MS2,BSN,BSN,BSN,BSN,BSN,39,GPRS RLC/MAC: Header of Control Block,Uplink,Payload Type,Downlink,Payload Type,S/P and RRBP: NW requires to MS for sending,Packet Control Acknowledgement control message,TFI (Optional): Temporary Flow Identity,U
36、SF: Uplink State Flag,40,GPRS Network Mode,Network Mode of Operation (NMO broadcasted within SI13),NMO2: no co-ordination,Double registration,Location Updating AND Attach or RAU IMSI Detach AND GPRS Detach,No Paging co-ordination,Impossible to receive a CS Paging during a GPRS transfer,NMO1: co-ordi
37、nation,Single registration,Combined procedures,Paging co-ordination,CS Paging are sent on PACCH during a GPRS transfer,41,Classes the Mobiles,MS class,Class A,Mobile registered in both modes,Able to perform both operations simultaneously (GSM call + Retrieve an email),Technically very difficult (2 r
38、adios needed),Class B,Mobile registered in both modes,Only one service at one time (either call OR email) Priority for GSM,Class C,Mobile registered in one mode (GSM or GPRS),42,GPRS: MultiSlot Class,43,Session ManagementOverviewUsed to manage PDP contextsActivationDeactivationModificationPDP contex
39、t: logical association between a MS and PDN (Public DataNetwork) running across a GPRS networkThe PDP context defines aspects such as:Routing,QoS Security,PDP1 / APN1,PDP1 / APN1,Billing,PDP2 / APN2,PDP2 / APN2,Etc,44,EDGE,Enhanced Data rates for GSM EvolutionAppeared in Release 99,Increase data rat
40、e on air interface Rate can be multiplied by 3,IR HARQ AMC Important modification related to signal processingFew modifications within RLC/MAC(Increase ARQ window size, Compressed ACK)LLC and SNDCP: same as GPRS,45,Modulation GPRS vs EDGE,GMSK Vs. 8PSK,GMSK: Gaussian Minimum Shift Keying,1 bit onto
41、one symbol,8PSK: 8 Phase Shift Keying,3 bits onto one symbol, Transfer rate * 3,46,Modulation GPRS vs EDGE,Reduced decision interval and therefore more affected by noise Need robust radio link,47,Modulation GPRS vs EDGE,More complicated signal processing to differentiate the constellation,48,EDGE: R
42、LC/MAC,Modulation and Coding SchemesGPRS: 4 Coding Schemes (CS1 to CS4),8PSK: 9 Modulation and Coding Schemes (MCS),49,EDGE: RLC/MAC,EGPRS block structure,EGPRS uses the GSM Normal Burst for data transfer 4 Normal Bursts used to form a Radio Block,Stealing bits,In GSM, used to indicate FACCH,In GPRS
43、 and EGPRS, used to indicate coding scheme,Stealing bits are combined with the encrypted bits Table gives the MCS used and header type,CS1 always used for RLC/MAC Control Blocks,50,EDGE: RLC/MACDownlink RLC/MAC Header Type 1Used for MCS7, MCS8 and MCS9Two RLC blocks per radio block,EGPRSSupplementar
44、y Polling (requests Ack/Nack and itstype),Temporary FlowIdentifier,Uplink State Flag(which TBF isallowed to sendon next block),Block SequenceNumber 1Block SequenceNumber 2Coding andPuncturing Scheme (channel coding andpuncturing used forthe data part),51,EDGE: RLC/MAC,Downlink RLC/MAC Header Type 2,
45、Used for MCS5 and MCS6,Downlink RLC/MAC Header Type 3Used for MCS1, MCS2, MCS3 and MCS4,Split Block indicator,(indicates if some userdata is retransmitted,using 2 blocks,resegmentation),52,EDGE: RLC/MAC,Uplink RLC/MAC Header,Type 1,Rtransimit Block (indicates whetherany of the RLC data blocks have,been sent previously),Type 2,Type 3,
