Marius Brînzea, Supervisor: Meriel Huggard OPNET Modeler Release 15 - UMTS library Featur es: • Po wer contr ol, GPRS attac h; • RLC Modes: AM, UM, T rM; Admission Control • Pri or it y ha nd li ng of da ta flows ba sed on tra ffi c cla ss at MAC • T raffic classes - conve rsati onal, strea ming, inter activ e, and backg round • One QoS pr of il e per tr af fi c cl as s of a UE • W-C DMAair int erf ace (FDD mod e onl y) • CE LL _D C H ( DSCH / DCH) // C EL L _F AC H (FACH / RACH) // Logical and transport channels •Int ra- RNC har d and sof t handover s Limitations: • GPRS deta ch • QoS Parameters (up/down-l ink data rates only) • QoS negotiation/renegotiat ion • IP Suppor t between RNC and Node-B (onl y UDP for Iub, IP or ATM) • No supp or t for parall el spreading codes on dedi cated chann el • No sup port for hig h-s pee d dow nlink pac ket access (HSDP A) • No mob ili ty pri or to attachmen t • Inter -RNC and inter -SGSN hando vers Motivation: HSD P A (Hig h Spe ed Downli nk Pa cket Acc ess ) is a mob ile communica tions pro toc ol tha t aims to pro vid e mob ile , wir eless dat a commun ica tion spe eds compar abl e to those of sta nda rd wir ed broa dband services Current HSDPA sc heduling al gori thms ar e very basi c in design and ther e have been new, mor e sophis tic ate d algori thms pro posed by the aca demic community. Mos t of these new al gori thms have not been tested in live test-bed scenar ios or even with industri al st re ng th simulators ; ther ef or e it is very di ff icul t to commen t on their pe rf or manc e in a mean ingfu l and critic al way . Research Points: 1. Ana ly ze the UMT S Release 5 spe cificatio ns in ord er to dis tingui sh key fea tures tha t nee d to be int egr ated in a val id HSD P A simula tio n env iro nment 2. Analyz e in deta il the oper at ion of la ye rs 1 and 2 of the radio interf ac e pr ot oc ol st ac k in UTR AN and the ir imp lement ati on in the OPN ET UMT S mod el 3. Identi fy and de scribe the key components that require modi fi cations to match the HSDP A 3GPPstandard 4. Pr opose and imp lement thecha nge s req uired in a new model lib rar y 5. Pe rfo rm simula tio n exp eri ments to ana ly ze the beh avi our of the pro posed cha nge s Introduction Implemented features: • Eb/No – SNR measureme nt per packet on the DSCH transport channel; • CQI value reporting from a UE’s MAC to Node-B’s RLC/MAC process in order to accommodate MCS schemas; • MAC-hs module in the Node-B process to accommodate various packet schedulers; • Thorough analysis of the TTI model and of the data structures for mapping of Transport to Physical Channels; • QPSK and 16-QAM capability, fixed SF; •Added HSDPA-specific UE Attributes Implementat ion issues: • Highly complex and tightly coupled components; • Hard coded values taken into account for TTI calculation; • HARQ process model coded but not implemented; Updat e the HS DP A model li brar y t o include: Mult iple code al lo cati on / mult iple HSPS DCH phys ical channels mapped to the HS DSCH transport cha nnel to ach ieve high downl ink spe eds (up to 10. 8Mb ps ) Implement the use of the HARQ module Cha nge the T ran smissi on Ti me Int erv al value for a fra me to 2ms , the equ iva len t of 3 slots Up gr ade the uplink channel to match UMTS R6 spec if ications (HSUP A) for sp eeds of up to 5.7 Mbp s. If imp lement ing HSUPA the follow ing key fea tur es need to be imp lement ed: • HSUPA unlike HSDPA don’t use AMC, instead it uses Turbo coding with QPSK modulation. • Power control is used in HSUPA unlike HSDPA • HSUPA uses 10ms TTI (and optionally 2ms) • HSUPA supports Intra Node B “softer” and Inter Node B “soft” HandOver • The scheduling in HSUPA is distributed between the UE and the Node B OPNET model libraries HSDP A System Simu lator Future work HSDPA / UMTS Network Improving HSDPA network performance Building an HSDPA system simulation with OPNET M.Sc. in Computer Science (Networks and Distributed Systems) HSDPA protocol architecture, modified parts highlighted UMTS Release 99 UMTS Release 5 (HSDPA) • TTI = 10, 20, 40, 80 ms • Variable SF = 1 – 256 • More transport block per TTI • Convolutional code or turb o codes • QPSK only • Configurable CRC • Scheduling in RNC • Retransmission in AM RLC • Power control • Soft hand off • TTI = 2 ms • Fixed SF = 16 • One transport block per TTI • Turbo codes only • QPSK and 16QAM according to UE capability • CRC of 24 bits • Scheduling in Node B • Physical layer retransmissions •Adaptive modulation HSDPA KEY FEATURES Fast link adaptation techniques based on multiple Modulation and Coding Schemes Fast Hybrid Automatic Repeat Request (HARQ) algorithms. Short TTI (2ms) Fast scheduling in the Node-B shares the HS-DSCH among the users
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Marius Brînzea, Supervisor: Meriel Huggard
OPNET Modeler Release 15 - UMTS library
Featur es:
• Power control, GPRS attach;• RLC Modes: AM, UM, TrM; AdmissionControl• Priority handling of data flows based ontraffic class at MAC• Traffic classes - conversational, streaming,interactive, and background• One QoS profile per traffic class of a UE• W-CDMAair interface (FDD mode only)• CELL_DCH (DSCH / DCH) // CELL_FACH(FACH / RACH) // Logical and transportchannels•Intra-RNC hard and soft handovers
Limitat ions:
• GPRS detach• QoS Parameters (up/down-link data ratesonly)• QoS negotiation/renegotiation• IP Support between RNC and Node-B (onlyUDP for Iub, IP or ATM)• No support for parallel spreading codes ondedicated channel• No support for high-speed downlink packetaccess (HSDPA)• No mobility prior to attachment• Inter-RNC and inter-SGSN handovers
Mot iva t ion :
HSDPA (High Speed Downlink Packet Access) is a mobile communications protocol that aims toprovide mobile, wireless data communication speeds comparable to those of standard wiredbroadband services Current HSDPA scheduling algorithms are very basic in design and therehave been new, more sophisticated algorithms proposed by the academic community. Most ofthese new algorithms have not been tested in live test-bed scenarios or even with industrialstrength simulators; therefore it is very difficult to comment on their performance in ameaningful and critical way.
Research Points:
1. Analyze the UMTS Release 5 specifications in order to distinguish key features that need tobe integrated in a valid HSDPA simulation environment2. Analyze in detail the operation of layers 1 and 2 of the radio interface protocol stack inUTRAN and their implementation in the OPNET UMTS model3. Identify and describe the key components that require modifications to match the HSDPA3GPP standard4. Propose and implement the changes required in a new model library5. Perform simulation experiments to analyze the behaviour of the proposed changes
Introduction
Implemented features:
• Eb/No – SNR measurement per packeton the DSCH transport channel;
• CQI value reporting from a UE’s MACto Node-B’s RLC/MAC process in orderto accommodate MCS schemas;
• MAC-hs module in the Node-B processto accommodate various packetschedulers;
• Thorough analysis of the TTI modeland of the data structures for mappingof Transport to Physical Channels;
• QPSK and 16-QAM capability, fixed SF;
• Added HSDPA-specific UE Attributes
Implementat ion issues:
• Highly complex and tightlycoupled components;
• Hard coded values takeninto account for TTIcalculation;
• HARQ process model codedbut not implemented;
Updat e the HSDPA model li brar y t o include:
Multiple code allocation / multiple HSPSDCH physical channels mapped to the HSDSCHtransport channel to achieve high downlink speeds (up to 10.8Mbps)Implement the use of the HARQ moduleChange the Transmission Time Interval value for a frame to 2ms, the equivalent of 3 slotsUpgrade the uplink channel to match UMTS R6 specifications (HSUPA) for speeds of up to5.7Mbps. If implementing HSUPA the following key features need to be implemented:
• HSUPA unlike HSDPA don’t use AMC, instead it uses Turbo coding with QPSK modulation.• Power control is usedin HSUPA unlike HSDPA• HSUPA uses 10ms TTI(and optionally 2ms)• HSUPA supports IntraNode B “softer” andInter Node B “soft”HandOver• The scheduling inHSUPA is distributedbetween the UE andthe Node B
OPNET model libraries
HSDPA System Simulator
Future work
HSDPA / UMTS Network
Improving HSDPA network performance
Building an HSDPA system simulation with OPNET
M.Sc. in Computer Science
(Networks and Distributed Systems)
HSDPA protocol architecture, modified parts highlighted
UMTS Release 99 UMTS Release 5 (HSDPA)
• TTI = 10, 20, 40, 80 ms• Variable SF = 1 – 256• More transport block per TTI• Convolutional code or turbo codes• QPSK only• Configurable CRC• Scheduling in RNC• Retransmission in AM RLC• Power control• Soft hand off
• TTI = 2 ms• Fixed SF = 16• One transport block per TTI• Turbo codes only• QPSK and 16QAM according to UEcapability• CRC of 24 bits• Scheduling in Node B• Physical layer retransmissions• Adaptive modulation
HSDPA KEY FEATURESFast link adaptation techniques based on multiple Modulation and Coding Schemes
Fast Hybrid Automatic Repeat Request (HARQ) algorithms. Short TTI (2ms)Fast scheduling in the Node-B shares the HS-DSCH among the users
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