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1 Revija19/2006/1 Ericsson Nikola Tesla .., , Ericsson Nikola Tesla d.d., Zagreb, Croatia : , HSDPA , H-ARQ 3,5 (3,5G) , MAC-hs , AMC , QPSK , 16QAM Key words:High Speed Downlink Packet Access, HSDPAHybrid Automatic repeat Request, H-ARQ3,5 Generation (3,5G)Fast Link AdaptationMedium Access Control - high speed, MAC-hsFast Channel SchedulingAdaptive Modulation and Coding, AMCQuadrature Phase Shift Keying, QPSK Quadrature Amplitude Modulation, 16QAM , , 3G. (HSDPA - High Speed Downlink Packet Access) (WCDMA Wi-deband Code Division Multiple Access) . HSDPA ( 14 /), , .. . , . , , , , , , (MAC-hs - Medium Access Control - high speed). , HSDPA ( RBS RNC), HSDPA, HSDPA.High Speed Downlink Packet AccessAbstractData services are expected to have signifcant growth over the next few years and will likely become the dominant source of 3G traffc. High Speed Downlink Packet Access (HSDPA) provides impressive enhancements over Wideband Code Division Multiple Access (WCDMA) for the downlink. It offers peak data rates of up to 14 Mbps, resulting in a better end-user experience for downlink data applications, with shorter connection and response times. This article is organized as follows:First comes the description of HSDPA physical channel confguration and protocol layer changes. Next, HSDPA key aspects and new features are presented (short TTI, Shared Channel Transmission, Fast Channel-Dependent Scheduling, Fast Link Adaptation, Amplitude Modulation and Coding, Fast Hybrid ARQ, Power Allocation). Also, transport network confguration and architectural impact are presented and a comparison to Release99 downlink packet access possibilities is made.Ericsson Nikola Tesla Revija19/2006/1 21. . , (. 1.) (NMT- Nordic Mobile Telephony), (FSK -Frequency Shift Key-ing) . NMT (FDMA - Frequency Division Multiple Access), , (DL - Down Link) (UL - Up Link) . , NMT , , , . (GSM - Global System for Mobile Communica-tion), NMT (.2.). (), , . (TDMA - Time Division Multiple Ac-cess), , , . , 2G, 9,6 /, , . , , GSM (LAN - Lo-cal Area Network), (CS - Circuit Switched). GSM , . , ( LAN, ). , 2,5G, .. 2G 3G. : (HSCSD - High Speed Circuit Switched Data) 57,6 /, GSM. , . , , 57,6 /. (GPRS - Ge-neral Packet Radio Service) . GPRS : GPRS - (SGSN - Serving GPRS Sup-port Node), GPRS - (GGSN - Gateway GPRS Support Node). GPRS , , X.25 IP , 115 /. , (QoS Quality of Servi-ce), . , (, , , , ..) , . GSM (EDGE - Enhanced Data rates for Global Evo-lution) , , 230 /, , . . . 1: () NMT 450 453-457,5463-467,5180 () GSM 900 DCS 1800890-915935-9601710-17851805-18809922992. 2: S Revija19/2006/1 Ericsson Nikola Tesla 8-PSK, . EDGE GSM. , ( ). - 144/ ( 128 /) , 384 /. 3G - (), (). . 3. (UMTS -Uni-versal Mobile Telecommunication System). , . , , , , , , . UMTS (. 4.), , (WCDMA - Wideband Code Divisi-on Multiple Access). , , , . , , 4G, , 3G, 3G (. 5.). 3G 4G, . (HSDPA -High Speed Downlink Pa-cket Access) . 3: UMTS. 4: UMTS. 5: ()UMTS1920 - 19802110 - 2170Node Radio Access Network Core Network Eksterne mree AMPS GSM GPRS EDGE GSM WCDMA HSDPA Ericsson Nikola Tesla Revija19/2006/1 4 , 3G WCDMA, 3GPP R5 R6. HSDPA, .. 3.5G , , . HSDPA . 1,8 / , 14 /. , (download) , , (real-time applications). , , , , :AMC - Adaptive Modulation and Coding - .H-ARQ - Fast Hybrid Automatic repeat Request - .FCSS - Fast Cell Site Selection - TTI - Short Transmission Time Interval - .Shared Chanell Transmission- / .Fair and fast scheduling at Node B- .2. HSDPA , HSDPA, UMTS (DCH, DSCH, FACH) , HSDPA . , (AMC - Adaptive Modulation and Coding). , , (channel conditions) , . (TTI - Transmission Time Interval). TTI (TTI = 2 ) R99 (TTI = 10, 20, 40 80 ). , , HSDPA (H-ARQ - Fast Hybrid Automatic repe-at Request). (UE - User Equipment) RBS RBS , ( ). , HSDPA , (MAC), MAC hs. .. 6: HSDPA S Revija19/2006/1 Ericsson Nikola Tesla 2.1. HSDPA . , , , , HSDPA : HS-PDSCH, HS-DSCH, HS-SCCH, HS-DPCCH (. 6.). High Speed Physical Downlink Shared Channel (HS-PDSCH) HSDPA HS-DSCH. 3 GPP 15 HS-PDSCH , 5 (SF - Sprea-ding Factor). High Speed Downlink Shared Channel(HS-DSCH) , . HS-DSCH , (channelization ), . HSDPA , 2 . , , 2 , (PDU - Packet Data Unit), .. , H-ARQ, (TFRC - Transport Format and Resource Combination), . , H-ARQ . HSDPA 5 , 15 . HS-DSCH : High Speed Dedicated Physical Control Channel (HS-DPCCH) (SF=256). HS-DPCCH DL (ACK / NACK), . (RBS) (CQI - Channel Qualitiy In-dicator), RBS (AMC). (Software HO - So-ftware Hand Over), RBS. High-Speed Shared Control Channel (HS-SCCH) (SF=128), . , 2 , : - UE ID , H-ARQ TFRC , HS-DSCH. UE, HS-DSCH. UE , . 7: HSDPA Node B Frame protocol Transport HSDPA user planeHSDPA Ericsson Nikola Tesla Revija19/2006/1 6. 9: HS-DSCH . 10: . 8: HS-SCCH , (Software HO - Software Hand Over).2.2. , H-ARQ , (Medium-Ac-cess Control, MAC-hs), RBS. MAC-d RLC - RNC (. 7.). HSDPA , 7 Revija19/2006/1 Ericsson Nikola Tesla , . 2.2.1. HSDPA TTI ( ) . , , , . 75 . , TCP/IP (, Web-), (Round Trip Time). HS-DSCH, HSPDA, . , . TTI . 2 . , , . (TTI) HSDPA: - Fast Link Adaptation - Fast Hybrid ARQ - Fast Chan-nel - Dependent Scheduling.2.2.2. HSDPA : HS-DSCH. , (SF - Spreading Factor) 16, . , (sharing) , , .. (Sha-red Channel Transmission). , . , , 15, ( ), 5, 10 15 , . 5 . . 8. , HS-DSCH. HS-SCCH, HS-DSCH, , (de-sprea-ding), , .2.2.3. HS-DSCH , (Scheduling) . (UE), , (. 9.). , RBS, MAC-hs. TTI , HS-DSCH, , . 11: Ericsson Nikola Tesla Revija19/2006/1 8 , . (UE), (. 10.). HSDPA : Proportional Fair Scheduling Round Robin C/I. (Proportional Fair Scheduling) , , . : ; . , 2 (TTI), . UE (UE measurement reports), (path loss), (fading) . , , , . , . , , , Round Robin. Round Robin . , , . , , , . , . Max C/I Ratio ( ) , . Ro-und Robin Max C/I . , . . best effort (Pro-portional Fair) , . 2.2.4. HSDPA (WCDMA) SF (Spreading Factor) (AMC - Adaptive Modulation and Coding), , . HS-DSCH . 12: QPSK 16QAM 1: HSDPA TFRC . (/)1 QPSK 1/4 1,82 QPSK 2/4 3,63 QPSK 3/4 5,34 16 QAM 2/4 7,25 16 QAM 3/4 10,79 Revija19/2006/1 Ericsson Nikola Tesla QPSK HS-DSCH 16QAM, ( 1.), , . 16QAM QPSK, , . , (effective code rate). , , ARQ. : : . 13: H-ARQ. 14: HS-DSCH , HS-DSCH RBS. (common) (dedicated chan-nel), HS-DSCH, (. 11.). , (jitter), , . TTI HS-DSCH , R99, TTI. . , , .Ericsson Nikola Tesla Revija19/2006/1 10. 15: HARQ. 16: , RBS , , , , . QPSK (. 12.). , TTI = 2 , UE. UE , , . 16QAM , RBS, , , . 16QAM , , QPSK. , ( ) , (, , ) .2.2.5. (H-ARQ Fast Hybrid Auto-matic repeat Request) , ACK , . (CRC - Cyclic Redundancy Check, Checksum), . , , (NACK - Ne-gative Acknowledgment). NACK, . HSDPA : Soft Combining , Incremental Redundancy (IR) / ,11 Revija19/2006/1 Ericsson Nikola Tesla . 17: (. 13.).Soft Combining , , 5 , RBS . UE , , NAQ RBS. , . , , , . . , UE , .Incremental Redundancy (IR) IR Soft Combining, , , .. . , , (. 14.). HSDPA RBS MAC-hs, .. RBS, , . , UE, , HARQ RBS , (Round Trip Time) 60 (. 15.). 3. HSDPA , HSDPA , . HSDPA .3.1. WCDMA (RBS RNC) HSDPA RBS, (. 16.): , MAC-hs ( HS-TX15 TX3.x) ( P4.GA). HSDPA , , , , .. RBS: , , ARQ. , HSDPA, RBS, MAC-hs. HSDPA RNC, : ( P4.GA). . 17. . , HSDPA , UMTS/WCDMA, Ericsson Nikola Tesla Revija19/2006/1 12(UBR) VC AAL2 ( , AAL2).UBR (best effort), , HSDPA , B best effort . HSDPA RBS - RNC (HSDPA Iub Flow Control) Iub RBS, . Iub ,