移動通信與仿真5-hsdpa.ppt

HSDPA - FDD,吳偉民 電子與信息工程系 ,HSDPA - FDD,Overview,Protocol Stack,MAC Layer Evolution,Transport Channel,Physical Channels,Evolution: HSDPA +,Terminal Capability Classes,Timing Structures,HSDPA - Overview,+ HSDPA stands for High Speed Downlink Packet Data,+ Release 5 feature of 3GPP/UTRAN,+ a major upgrade to 3G system capabilities,+ HSDPA shortens round-trip time between network and terminals,+ HSDPA reduces variance in downlink transmission delay,+ HSDPA does not improve uplink data rates (see e-DCH called HSUPA),+ HSDPA uses DCH transport channel,HSDPA - Overview,+ Optimized for high-speed downlink data only SF=16 codes used,+ Shorter frames (2ms including 3 Timeslots) enables faster reactions to changing channel conditions (AMC) enables faster retransmission protocol (HARQ),+ Adaptative Modulation and Coding (AMC) adapts the following transmission format attributes modulation scheme (QPSK, 16QAM) number of physical channel redundancy version error correction rate,+ The UE measures the channel conditions, and indicates to Node-B the highest data rate (AMC) it could support through CQI indication,HSDPA - Overview,+ Fast scheduling performed by the Node B,+ The HARQ protocol implements a fast acknowledged data transmission scheme retransmissions including the original information bits, but the data packet contains more redundancy Stop-And-Wait ARQ scheme is used in HSDPA N HARQ Processes, each Stop-And-Wait ARQ,UE 2,UE 3,UE 1,HSDPA - Overview, Multiplexing Spreading Code for one UE imposed by capability class Users are mulitplexed both in time,TTI = 2ms,Codes,Time,HS-DSCH-related Shared Control Channel (HS-SCCH),HS-DSCH,High Speed Physical Downlink Shared Channel (HS-PDSCH),Dedicated Physical Control Channel (uplink) for HS-DSCH (HS-DPCCH),+ UE Side: MAC-hs is responsible for HARQ -ACK (Hybrid Automatic Repeat Request) Re-ordering,+ NodeB Side: MAC-hs is responsible for Flow Control Scheduling/Priority Handling HARQ TFRI,MAC-d,MAC-hs,PHY,MAC-hs,PHY,L1,L2,HS-DSCH FP,L1,L2,HS-DSCH FP,MAC-d,UE,Node B,RNC,HSDPA Protocol Stack,Node B: Scheduler (Rec 25.321 11.6.1), Schedules all UEs within a cell Services priority queues: The scheduler schedules MAC-hs SDUs based on information from upper layers. One UE may be associated with one or more MAC-d flows. Each MAC-d flow contains HS-DSCH MAC-d PDUs for one or more priority queues Determines the HARQ Entity and the queue to be served Sets the TSN for new data blocks being transferred from the selected queue: Set the TSN to value 0 for the first MAC-hs PDU transmitted for each Queue ID within an HS-DSCH Increment the TSN within one for each transmitted MAC-hs PDU on each Queue ID within an HS-DSCH Schedule new transmissions and retransmission (based on the status reports from HARQ Processes) Determines the redundancy version (for each transmitted and retransmitted MAC-hs PDU),HSDPA Protocol Stack,Node B: HARQ Entity (Rec 25.321 11.6.2), There is one HARQ entity for each Ue The HARQ entity sets the Queue ID in transmitted MAC-hs PDU to value indicated by scheduler The HARQ entity sets the transmission sequence number (TSN) in transmitted MAC-hs PDU to value indicated by scheduler,Node B: HARQ Process (Rec 25.321 11.6.3), The HARQ process sets the New Data Indicator in transmitted MAC-hs PDU : to the value “0” for first MAC-hs PDU transmitted by a HARQ Process not increment for retransmission of a MAC-hs PDU increment with one for each transmitted MAC-hs PDU containing new data The HARQ process processes received status message to the scheduler,HSDPA Protocol Stack,MAC-d for UEn,MAC-d for UE2,HARQ Entity,UE3,HARQ Entity,UE2,SCHEDULER,Queue ID 0 TSN 3 New Data Ind,Node B Side,MAC-d for UE1,HSDPA Protocol Stack,Queue ID 1 TSN 3 New Data Ind,Reordering Entity,UE Side,HARQ Entity,UE1,HARQ Process (rec 25.321 ): If the MAC-hs PDU is received within 5 sub-frames from the reception of the previous MAC-hs PDU intended for this HARQ process MAC-hd PDU is discarded,HSDPA Protocol Stack,MAC-d for UE1,HSDPA MAC Layer,UE Side MAC Architecture: Rec. 25.321 4.2.3,HSDPA MAC Layer,UTRAN Side MAC Architecture: Rec. 25.321 4.2.4,MAC-hs SDU,MAC-hs SDU,MAC-hs SDU,Padding,HSDPA MAC Layer,PDCP: TCP/IP Compressed,AMR Block Voice,MAC-hs Header,MAC-d PDU Size = 336 bits,MAC-d PDU Size = 336 bits,MAC-d PDU Size = 144 bits,! MAC-hs PDU !,UE1 Data,MAC-hs Payload,HSDPA MAC Layer,MAC-hs Header: Rec. 25.321 9.2.2,VF,Queue ID,TSN,SID1,N1,F1,SID2,N2,F2,VF (1 bit): Version Flag: extension capabilities 0 Normal 1 reserved Queue ID (3 bits) : indication for reordering queue in the receiver, set by HARQ Entity TSN (6 bits): Transmission Sequence Number: used for reordering purposes to support in-sequence delivery higher layers. Number of Sequence by Queue ID SID (3 bits): Size Index Identifier, index corresponding to MAC-d size of a set of consecutive MAC-d PDUs See in 25.331 a MAC-d PDU size Info N (7 bits): Size Number of consecutive MAC-d PDUs with same Index Set Max number PDUs per TTI in FDD 70 F (1 bit): Flag indicating if more fields are present in the MAC-hs Header,SIDk,Nk,Fk,HSDPA Transport Channel,HS-DSCH: High-Speed Downlink Shared Channel: Rec. 25.212 4.5,Slot 0,Slot 1,Slot 2,2ms,One transport block once every TTI (2ms), associated with one DCH,MAC-hs PDU = 1 block HS-DSCH,HSDPA Transport Channel,Hybrid ARQ for HS-DSCH: Rec. 25.212 4.5.4,The hybrid ARQ functionality matches the number of bits at the output of the channel coder to the total number of bits of the HS-PDSCH set to which the HS-DSCH is mapped. The hybrid ARQ functionality is controlled by the redundancy version (RV) parameters. The exact set of bits at the output of the hybrid ARQ functionality depends on the number of input bits, the number of output bits, and the RV parameters. The hybrid ARQ functionality consists of two rate-matching stages and a virtual buffer .,HS-DSCH hybrid ARQ functionality,HSDPA Physical Channel,HS-PDSCH : High Speed - Physical Downlink Shared Channel Rec. 25.211 3,TTI = 2ms,Codes,Time,ONLY ONE block HS-DSCH,HS-PDSCHs,k= 4 M= 2 for QPSK 320 bits/slot M= 4 for 16QAM 640 bits/slot,slot #0,slot #1,slot #2,Size of Transport Block: TFRI,HSDPA Physical Channel,HS-SCCH : High Speed Shared Control Channel Rec. 25.211 2,The HS-SCCH is a fixed rate (60 kbps, SF=128) downlink physical channel used to carry downlink signalling related to HS-DSCH transmission,HSDPA Physical Channel,Coding for HS-SCCH, Rec. 25.212 4.6,HS-SCCH Part 1,HS-SCCH Part 2,Slot are aligned time with the CPICH Rate 1/3 convolution coding QPSK modulation Up to 4 HS-SCCHs per UE (see 25.214 6A.1.1),Slot #1,Slot #2,HS-SCCH: 7680 chips,Slot #0,HSDPA Physical Channel,Coding for HS-SCCH, Rec. 25.212 4.6,UE identity (16 bits): xue,1, xue,2, , xue,16 UE identity is the HS-DSCH Radio Network Identifier (H-RNTI sets in Radio Bearer Setup message, see 25.331 b) Channelization-code-set information (7 bits): xccs,1, xccs,2, , xccs,7 P (multi-)codes starting at code O xccs,1, xccs,2, xccs,3 = min(P-1,15-P) xccs,4, xccs,5, xccs,6, xccs,7 = |O-1-P/8 *15|,HS-PDSCHs,slot #0,slot #1,slot #2,Modulation scheme information (1 bit): xms,1,HSDPA Physical Channel,Redundancy and constellation version (3 bits): xrv,1, xrv,2, xrv,3 Parameters of the second rate matching stage in HARQ functionality (see Rec 25.212 ) New data indicator (1 bit): xnd,1 Hybrid-ARQ process information (3 bits): xhap,1, xhap,2, xhap,3 Identifier process sent by RRC in HARQ Info, see 25.331 a Number of Processes Memory size Process Memory size: Maximum number of soft channel bits available in the virtual IR buffer Transport-block size information (6 bits): xtbs,1, xtbs,2, , xtbs,6 TFRI (Transport Format Resource Indicator), Rec 25.321 9.2.3 Let kt be the sum of the two values: kt = ki + k0,i. The transport block size L(kt) can be obtained by accessing the position kt.,Coding for HS-SCCH, Rec. 25.212 4.6,HSDPA Physical Channel,Coding for HS-SCCH, Rec. 25.321 Annex A,HSDPA Physical Channel,HS-DPCCH, Rec. 25.213 ,Code Allocation, Rec 25.213 .2,HSDPA Physical Channel,Frame Structure for HS-DPCCH, Rec. 25.211 ,HS-DPCCH 10 bits / slot,HSPDA Physical Channel,HS-DPCCH, Channel Coding of HARQ-ACK Rec. 25.212 4.7.1,Stop-And-Wait (SAW) ARQ scheme,Node B,UE