1、HSDPA,High Speed Downlink Packet Access,Table of Contents,OverviewFeature of HSDPAImage of HSDPAComparison Table between HSDPA & R99 Technical FeaturesLink Adaptation (Adaptive Modulation and Coding Scheme, Adaptive Scheduling)Hybrid-ARQ (Hybrid-Automatic Repeat Request) TTI (Transmission Time Inter
2、val) improvement at HSDPA Related Channels Migration from R99 to HSDPA(R5)Node-B FeaturesRNC FeaturesBenefitsSubscriber BenefitsOperator Benefits,Overview Feature of HSDPA, Image of HSDPA& Comparison between HSDPA and R99,Overview Feature of HSDPA,High downlink peak rate14.4Mbps with 15 HS-PDSCH (SF
3、16)codes7.2Mbps with 10 HS-PDSCH (SF16)codes (First Proposal for H3G)3.6Mbps with 5 HS-PDSCH (SF16)codesRealization of High speed transmission by Link Adaptation, Detail scheduling at short TTI and Hybrid ARQ on Radio LinkLarge Radio link Capacity by Link Adaptation (QPSK,16QAM)High efficiency in tr
4、ansmission & error correction by Hybrid ARQTTI (Transmission Time Interval) is 2ms (Rel99 is 10ms)Efficient use of System ResourcesSharing fat pipe among UEs not assign Dedicated CH independentlyMinimum impact to existing Rel99 H/WMost of Rel99 HWs are reusable. Hs-CHC for NB, a few additional cards
5、 of RNC are necessary to handle HSDPA protocol.,HS-PDSCH Particular DL CH for HSAPA. Use for user data transmission.,Overview Image of HSDPA (TTI, Adaptive scheduling),Fast scheduling in time (2ms) and code domain (15 parallel codes) reduces delay and improves peak rateEfficient use of System Resour
6、ce by sharing fat pipe among UEs,Spreading Factor 16 Service Quality is corresponding to PS128 x 15 with QPSK, PS384 x with 16QAM.,Efficient use of power resource by 2ms scheduling according to user propagation condition. Maximum 15 spreading code resources can be shared among users,In case of R99,
7、the large amount of Tx power is necessary to user who is in the bad propagation condition and also spreading code resource is occupied during no data receiving.,Overview Image of HSDPA (QPSK,16QAM,HARQ),QPSK,DATA,DATA,DATA,16QAM,Transmission data,Re-transmission,NG,NG,OK,Ignored,Receiving data,FEC &
8、 ARQ (R99),Hybrid-ARQ,NG,OK,=,In case of R99, error correction is implemented by 1 transport block each and TTI of PDSCH is transmitted by 10ms (1 radio frame). If the unit which is transmitted at once is large, also abandoned data amount will be large incase of decoding failure.,In case of HS-PDSCH
9、, delay is mitigated because error correction is implemented 2ms each. In HARQ process, NG data is combined to re-transmitted data and decoded. Thus high efficiency can be realize.,At good propagation condition point, large amount of data can be transmitted.,Small amount of transmission data at poor
10、 propagation condition.,Ignored,Re-transmission,Transmission data,Receiving data,Re-transmission,Combining,Overview Comparison between HSDPA and R99,Overview Comparison between HSDPA and HDR,According to spreading modulation, difference of multiplexing method, and chip rate, transmission efficiency
11、is different between W-CDMA and CDMA2000.,Basic logic and function are almost same between HSDPA and HDR.,Technical Features Link Adaptation (Adaptive Modulation and Coding Scheme, Adaptive Scheduling) Hybrid-ARQ (Hybrid-Automatic Repeat Request) TTI improvement at HSDPA Related Channels,Technical F
12、eatures Link Adaptation (1),Node B determines optimum transmission parameter settings according to the radio propagation environment in which each UE locates.,Sequence: 1. UE measures a P-CPICH receive power level. Based on the result, it notifies Node B of the recommended values of the above parame
13、ters.- Predicts a HS-PDSCH Rx power level from the P-CPICH Rx power.- Determines the recommended parameter settings and notify Node B of the result.= CQI (Channel quality indicator ) Reporting 2. According to the CQI value, Node-B determines optimum transmission parameter settings.,To improve system
14、 throughput, Node B prioritizes the UE in good propagation environment suitable for high speed data transmission.,Technical Features Link Adaptation (2) QPSK,16QAM,Modulation Scheme QPSK (Quadrature Phase Shift Keying) Phase modulation 2bits/symbol Less susceptible to noise - Mainly used in unstable
15、 radio propagation environment.16QAM (Quadrature Amplitude Modulation) Phase + Amplitude modulation 4bits/symbol Susceptible to noise - Mainly used in stable propagation environment.,Technical Features Link Adaptation (3) AMSC (Adaptive Modulation and Coding Scheme), Adaptive Scheduling,AMSC Accordi
16、ng to the radio propagation condition, this technique flexibly selects the transmission modulation scheme and encoding rate that enable high speed data transmission at a constant maximum transmission power.Adaptive Scheduling This technique selects and prioritizes a specific user in stable radio pro
17、pagation environment while implementing scheduling.,Technical Features TFRC (Transport Format and Resource Combination),Examples of theoretical bit rate by TFRC when using 15 parallel codes (Excluding deviation by foreign elements）,TFRC Based AMSC this is determined as needed by the system according
18、 to the CQI information (concerning the radio propagation environment in which each locates),Technical Features Link Adaptation (4),Backward compatibility with Release 99No change to Release 99 channelNew addition of the HSDPA associated channelCo-existence of the Release 99 channel and the HSDPA as
19、sociated channel within the same carrier Optimally sharing transmit power and spreading codes,Technical Features Link Adaptation (Adaptive Modulation and Coding Scheme, Adaptive Scheduling) Hybrid-ARQ (Hybrid-Automatic Repeat Request) TTI improvement at HSDPA Related Channels,Technical Features Hybr
20、id-ARQ (1),If UE should fail in decoding the received data, Node B retransmits the data. UE sends an ACK signal to Node B when it succeeds in the decoding. Otherwise it sends a NACK signal.This reduces the frequency of retransmissions between UE and RNC, resulting in improvement of transmission effi
21、ciency and minimization of data delay.UE can handle 8 HARQ process symmetrically as maximum. (Of course it is taken some time span for dealing of one HARQ process. Increasing the number of symmetric HARQ process produce higher efficiency related TTI improvement of HSDPA.)Two methods are available; C
22、hase combining and Incremental Redundancy.,FEC (Forward Error Correction) A method of communicating data used when data discarding or errors in is detected. User data is restored using redundant data added to it without the need for data retransmission.,ARQ (Automatic Repeat Request) In radio commun
23、ication systems the receiver who received an error frame requests a retransmission of frame to the transmitter.,Hybrid-ARQ,Chase combiningRetransmits the same data. No change in Redundancy Version.UE combines the decoding error data and the next receiving data. Provides the equivalent effect with ma
24、ximum rate combining,Technical Features Hybrid-ARQ (2),Encoder,UE,NG,NACK,Retransmission,+,Decoder,Decoder,OK,ACK,Soft combining,NodeB,With the conventional FEC, redundant bits that differ from those in previous transmission are retransmitted. No combining with the previous data.,Technical Features
25、Hybrid-ARQ (3),Incremental RedundancyAt the retransmission sequence the redundant bits are sent and combined with all received data. Dependent on Redundancy Version, redundant bits with a structure different from that in the previous transmission are transmitted in the second retransmission. At the
26、retransmission sequence only parity bits can be transmitted. Provides efficient error correction.,Encoder,UE,NG,Retransmission,Decoder,Decoder,OK,NACK,ACK,NodeB,Data required for decoding, which is generated together with redundant data when original data is encoded.,Redundant Bits + Parity Bits,At
27、the second retransmission different structure of redundant bits are sent.,With the conventional FEC, redundant bits that differ from those in previous transmission are retransmitted. No combining with the previous data is performed. Since the original data is also retransmitted, retransmission capac
28、ity is increased.,Technical Features Link Adaptation (Adaptive Modulation and Coding Scheme, Adaptive Scheduling) Hybrid-ARQ (Hybrid-Automatic Repeat Request) TTI improvement at HSDPA Related Channels,Efficiency of HARQ and Link Adaptation,Performing Hybrid-ARQ and Link Adaptation at a very short cy
29、cle of 2ms instead of the conventional 10ms to realize an effective transmission with less delay.,Technical Features TTI Improvement (1),Introducing the dedicated channels that realize the HSDPA management and high speed data transmission in Up/Down links.,Technical Features TTI Improvement (2),HS-S
30、CCH HSDPA dedicated DL Control CH Carries signals for decoding HS-PDSCH UE can simultaneously receive up to four HS-SCCHs (support for two HS-SCCHs is proposed in the initial service) HS-PDSCH HSDPA dedicated DL Data CH Carries RRC message and user data. HS-DPCCH HSDPA dedicated UL Control CH Carrie
31、s HARQs ACK/NACK signals. Carries CQI signals. DPCH (Associated DCH) Existing DPCH When used with HSDPA, it may be called Associated DCH.,SRNC,Node B,Node B,UE can receive HS-SCCH/HS-PDSCH and transmit HS-DPCCH to or from one cell at a time.,Technical Features TTI Improvement (3),TTI = 3 slots (2ms)
32、 SF = 16 (fixed) HS-DSCH is mapped.,M=modulation scheme QPSK 2 16QAM 4,Amount of data per slot QPSK 320bit 16QAM 640bit,Conventional Frame,HSDPA Frame,Technical Features HS-SCCH,Control Signals: Canalisation code set (7bits)： Represents number of multiplexed codes (First 3bits) + code number (Last 4
33、bits) of HS-PDSCH. Modulation Scheme (1 bit)：0 - QPSK、1 - 16QAM Hybrid ARQ Process Number(8bits)： Referencing this value, UE allocates the received data to the suitable Hybrid-ARQ process. Redundancy version (8 bits)：Represents the combination of 16QAM and QPSK used in HARQs Second Rate Matching. Ne
34、w data indicator (1bit)：In HARQ, the change of this bit indicates that a new data has been received (the data stored in the memory will be deleted).,TTI = 3slot (2ms) SF = 128 (fixed) CH bit rate = 60kbps (fixed),Technical Features HS-PDSCH,TTI = 3slot (2ms) SF = 16 (fixed) HS-DSCH is mapped,HS-DSCH
35、 VF (1bit)：Currently set as 0. it is reserved for extended function in future. Queue ID (3 bits)：UE refers to this value and assigns receiving data to appropriate “Re-ordering queue”. TSN (6bits)：This is used for ordering guarantee of receiving data as sequence number. SID (3bits)：It indicates Index
36、 of MAC-d PDU (= MAC-hs SDU) size. Correspondence between actual size and index is reported by RRC message for UE in advance. N (3bits)：It indicates sequent count of SIDs MAC-d PDU. F (1bit)：0 - MAC-hs header is continued. 1 - MAC-hs is terminated.,Technical Features HS-DPCCH,Feedback Signals ACK/NA
37、CK (1 bit)：1 - ACK, 0 - NACK In the case that no HS-PDSCH is received, ACK/NACK is not sent. ACK/NACK is transmitted for sequent sub-frame which is specified by ACK-NACK Repetition Factor reported by RRC message. Before the transmission of ACK/NACK is complete, the next HS-PDSCH can be received. CQI
38、 (5 bits)： Represents transport block size, number of multiplexed codes and modulation scheme. This signal is sent according to the parameter notified by the RRC message. CQI feedback cycle k: Indicates a cycle of transmitting CQI. CQI feedback offset l： Specifies a timing to start the transmission
39、of CQI. Repetition factor of CQI： Indicates the number of Sub-frames that consecutively transmit CQI.,TTI = 3slot (2ms) SF = 256 (Fixed) CH bit rate = 15kbps (Fixed,Technical Features TTI Improvement (4),HS-PDSCH Feature M (modulation scheme): Variable (up to 640 bits per slot) In the conventional s
40、cheme M was fixed to 1USER=1Code while HSDPA allows up to 15 codes to be shared. Both schemes takes 10ms to send 15 slots. But, since HSDPA sends 3 slots at every 2ms, it can increase the frequency for error correction with less delay.,Technical Features UE Categories,All Categories should be suppor
41、ted; however, based on knowledge of the UE market it can be valid to deploy a Node-B that does not fully support all of the UE categories. It is believed that to fully support 1 to 8, 11, and 12 would be adequate. Also based on simulations this gives the optimal throughput. It was observed in simula
42、tions that regarding Categories 9 and 10; 15 codes support is not necessary to achieve optimal system performance of HSDPA. It should however be noted that this does not mean that the Node-B will not be interoperable with a UE that declares as category 9 or 10 as the Node-B will just assign 10 codes
43、 to the UE, it is assumed a 15 code UE is capable of less than 15 code support.,Minimum Inter-TTI Interval UE capabilities do not the timing of an individual TTI transmission but do define how often one HS sub frame can transmit to the UE. The capabilities include information of the minimum inter-TT
44、I interval that tells whether consecutive TTIs may be used or not.1 TTI is consecutive2 One empty TTI between packettransmissions3 Two empty TTIs between packettransmissions.,Migration from R99 to HSDPA(R5) Node-B Features RNC Features,Migration from R99 to HSDPA(R5) HSDPA Protocol Architecture,DRNC
45、 does not exist in an application where Iur is not used. This figure does not show the UE end of MAC-c/sh since it is not used in HSDPA One MAC-hs exists for each UE and Cell.,Overview Traffic Route of DCCH/DTCH(HSDPA),DL DCCH (HSDPA) is mapped on DCH (not HS-DSCH).UL DTCH (Associated DCH) route is
46、still under consideration. There are two alternatives. A DHT terminates UL A-DCH. B HS-DST terminates UL A-DCH.,Migration from R99 to HSDPA(R5) Node-B General Requirement,H/W replacementNew high performance CHC cards for HSDPA (Hs-CHC,96CHC cards) are essential.One HSDPA CHC card per Node-B is neces
47、sary. New CHC cards can coexist with current R99 CHC cards.Other H/Ws are reusable. (if no special requirements)S/W updateS/W update (download) is essential, of course.,Migration from R99 to HSDPA(R5) Node-B HW Configuration for HSDPA,Base Rack,LPA or CAT (3+3) In case DRIC is used, CAT must be equi
48、ppedDUAMCO (3)CC (1+1)CHC cards (10)REP cards or DRIC (1+1)TRX cards (6) In case DRIC is used, Is not necessary,A-shelf,B-shelf,FAN2,FAN3,R99 CHC & Hs-CHC are enable to co-exist,SW update is mandatory,HSDPA CHC Card (CHC96 or hs-CHC) Is mandatory,Other H/Ws are reusable,Migration from R99 to HSDPA(R
49、5) Resource Comparison between R99 CHC(FV1/FV2) and CHC96/HS-CHC,Migration from R99 to HSDPA(R5) Node-B Features RNC Features,Migration from R99 to HSDPA(R5) RNC General Requirement,H/W replacementNew 2 additional cards, HS-DST and HS-PRLC are essential.New 2 cards, WCMP and WLSC are necessary to replace instead of CMP and BLSC.Other H/Ws are reusable. (if no special requirements)S/W updateS/W update (download) is essential, of course. Especially, F/W update of CMUX is necessary to control HS-PRLC.,
