PhD Thesis Mohmmad Anas 2009

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<p>Uplink Radio Resource Management forQoS Provisioning in Long Term EvolutionWith Emphasis on Admission Control and HandoverPhD ThesisbyMohmmad AnasA dissertation submitted tothe Faculty of Engineering, Science and Medicine of Aalborg Universityin partial fulllment for the degree ofDoctor of Philosophy.Aalborg, DenmarkJanuary 2009Supervisor:Preben Elgaard Mogensen, PhD,Professor, Aalborg University, Denmark.Co-supervisor:Klaus Ingemann Pedersen, PhD,Senior Wireless Network Specialist, Nokia Siemens Networks, Aalborg, Denmark.Assessment Committee:Laurent Schumacher, PhD,Associate Professor, University of Namur, Belgium.Carsten Ball, PhD,R&amp;D Manager, Nokia Siemens Networks, Munich, Germany.Tatiana Kozlova Madsen, PhD,Associate Professor, Aalborg University, Denmark.Defence Moderator:Flemming B. Frederiksen,Associate Professor, Aalborg University, Denmark.ISSN 0908-1224ISBN 978-87-92328-03-8Copyright c 2009, Mohmmad Anas.All rights reserved. The work may not be reposted without the explicit permission of the copyrightholder.To my parents Mr. Hasnain Alam and Late Mrs. Shaheena Begum.AbstractLong Term Evolution (LTE) is a beyond 3G wireless system based on a decentralized ar-chitecture which shall support end-to-end Quality of Service (QoS). The radio resourcemanagement functionalities in the LTE uplink is based on a dynamically shared chan-nel with fast Link Adaptation (LA) including Adaptive Modulation and Coding (AMC)and Fractional Power Control (FPC), Hybrid Automatic Repeat reQuest (HARQ), PacketScheduler (PS), Admission Control (AC) and handover. To provide efcient QoS con-trol, it is necessary that both AC and PS are QoS aware. The AC maintains the QoS ofin-progress bearers in a cell by admitting a new bearer only if all the existing and newbearers can be guaranteed their QoS requirements. Additionally, LTE will provide seam-less access to voice and multimedia services which is achieved by supporting handover.The problem of providing seamless access becomes even more important in LTE since ituses hard handover (break-before-make type). This PhD study mainly focuses on AC andhandover issues for QoS provisioning in LTE uplink.In the rst part, a novel AC algorithm is proposed for LTE uplink to fulll the re-quired QoS of new radio bearer and in-progress bearers. In this study Guaranteed BitRate (GBR) is considered as the main QoS parameter. The proposed AC algorithm esti-mates the required resources for the new and existing bearers to fulll their required GBRtaking into account users respective channel conditions. The proposed AC algorithm isbased on a closed-form estimator derived utilizing the FPC scheme standardized in 3GPP.To evaluate the performance of FPC based AC, a reference AC which does not take chan-nel conditions into account is proposed. Furthermore, a QoS aware PS is proposed andis combined with the AC algorithm for effective QoS provisioning. The performance isevaluated using a full-blown multi-cell, multi-user, semi-static system level simulator fol-lowing the 3GPP LTE standard. The results show that the FPC based AC, unlike referenceAC, is robust and automatically adjusts to the trafc mixes, cell load, and user channelconditions. Additionally, the proposed AC and PS framework guarantees the respectiveGBR requirements of different user classes in a best-effort trafc scenario with mixedGBR settings. Further, this framework is shown to guarantee the QoS of users with arealistic Constant Bit Rate (CBR) streaming trafc and an ON/OFF trafc source usingCBR trafc to model the ON periods.In the second part, performance of an intra-LTE hard handover algorithm is evaluatedat user speeds of 3 kmph to 120 kmph. Handover algorithm based on Received SignalStrength (RSS) and Carrier to Interference Ratio (CIR) measurements on downlink ref-erence symbols (pilots) is studied. Additionally, Layer 3 (L3) ltering in linear and log-arithmic domain is evaluated. A realistic estimate of measurement imperfections due tothe limited number of reference symbols is modeled and added to the handover measure-ments before L3 ltering. RSS on reference symbols is known as Reference Signal Re-vvi Abstractceived Power (RSRP) and is standardized as one of the measurements for intra-frequencyhandover in LTE. This study is evaluated using a detailed multi-cell, multi-user, dynamicsystem-level simulator i.e., a simulator suitable for mobility studies, following 3GPP LTErecommended assumptions. The results show that the downlink measurement bandwidthof 1.25 MHz will lead to best tradeoff between average number of handovers and aver-age uplink Signal-to-Interference-plus-Noise Ratio (SINR). Moreover, it is shown thatfor an adaptive choice of L3 ltering period, depending on the user speed, the gain forusing larger measurement bandwidth can be made negligible for a small penalty on signalquality.Dansk Resum 1Long Term Evolution (LTE) er den nyeste 3GPP standard, som er baseret p en dis-tribueret arkitektur med slutbruger QoS (Quality of service). Radio resource management(RRM) funktionerne i uplink (UL) er baseret p en flles dynamisk kanal med hurtig linkadaption (LA) med variabel kodning og modulation, power kontrol, samt Hybrid ARQ(automatic repeat request). Dynamisk pakketransmission og adgangs kontrol er ogs endel af konceptet for at sikre QoS. Adgangskontrollen har til opgave kun at tillade nyekald, hvis disse kan accepteres uden at kvaliteten af eksisterende kald bliver for lav, samtat QoS af det nye kald kan opfyldes. LTE har ogs en optimeret handover funktion, sombl.a. sikrer, at brugere kan skifte celle, uden at dette medfrer kvalitets forringelse.I frste del af dette studium analyseres adgangskontrol algoritmen til LTE. En ny al-goritme foresls, hvor eneste QoS parameter er guaranteed bit rate (GBR). Algoritmener baseret p et estimat af, hvor mange transmissions- resurser den nye bruger krver,samt antal resurser krvet af de eksisterende brugere for at opfylde deres minimumQoS. Der udledes et matematisk udtryk for dette, baseret p antagelserne i LTE ULmht. til power kontrol og dynamisk LA. En simpel reference adgangskontrol algoritmetestes ogs. Adgangskontrol algoritmen evalueres med en detaljeret quasi-statisk netvrkssimulator, med multiple celler, terminaler, osv., i overensstemmelser med LTE system-specikationerne. Resultaterne fra disse simuleringer viser, at den nye adgangskontrolalgoritme er robust og virker efter hensigten, s nye brugere kun gives adgang hvis detteer muligt uden at kompromittere QoS. Den nye algoritme er klart bedre end den testedereference adgangskontrol algoritme. Den nye adgangskontrol algoritme er ogs blevetevalueret sammen med en avanceret QoS pakketransmissions algoritme med minimumGBR krav. Ogs i dette tilflde viste det sig, at den foreslede adgangskontrol algoritmeviste gode resultater. Kombinationen af avanceret QoS adgangskontrol og pakketransmis-sion er ogs blevet studeret for data trak med ikke konstant pakkeaktivitet.I anden del at rapporten studeres handover, med fokus p intra-frequency handover. Enhandover algoritme baseret p terminalmlinger af signalstyrke og signal-til-interferenceblev undersgt. Forskellige ltre af disse mlinger blev undersgt for at nde det bed-ste kriterium til handovers. En realistisk modellering af diverse mlefejl ved terminalenvar en vigtig del af disse studier, bl.a. som funktion af mle-bndbredden, antal af refer-ence symboler, osv. De forskellige handover algoritmer blev evalueret i en dynamisknetvrkssimulator, som blev specielt udviklet til dette forml. Resultaterne viste, aten mle-bndbredde p 1.25 MHz var nok til at opn gode resultater, hvis signal-til-interference mlinger benyttes til handovers. Filterlngden af disse mlinger kan opti-meres afhngigt af hastigheden af terminalerne.1Translation by Klaus I. Pedersen and Jytte Larsen, Nokia Siemens Networks, Aalborg, Denmark.viiPreface and AcknowledgmentsThis thesis is the result of three years of PhD fellowship grant in the area of radio re-source management, mobility, and system performance analysis for B3G/4G systems.This project is co-nanced by the Aalborg University and Nokia Siemens Networks, Aal-borg, Denmark. The research is carried out at the Radio Access Technology section,Institute of Electronic Systems, Aalborg University under the supervision of ProfessorPreben E. Mogensen (Aalborg University) and Dr. Klaus I. Pedersen (Nokia SiemensNetworks). This thesis investigates the uplink radio resource management issues to pro-vide QoS support in 3GPP LTE systems.The presented work would not have been possible without being part of an inspir-ing network of colleagues, enabling interesting discussions and collaboration. First ofall, I would like to thank my PhD supervisors for their guidance, co-operation, and pa-tience. Their input has been vital, especially our technical discussions were instrumentalin improving my understanding of the subject, and enabled me to overcome the technicalchallenges. I would also like to thank Per-Erik stling who was my rst contact with theAalborg University and who has also been a good collaborator for the handover studies.Further, I would like to thank the members of the assessment committee who throughtheir detailed reading and constructive feedback have assisted me in the correction andclarication of the text throughout this dissertation.I would also like to point out the good collaboration with Francesco Calabrese andClaudio Rosa which has also led to common publications. Further, I would like to thankJeroen Wigard, Jens Steiner, Daniela Laselva, Per-Henrik Michaelsen, and Troels B.Srensen for their valuable inputs. The constant friendly support, assistance with adminis-trative tasks, and the proofreading provided by our section secretaries Lisbeth SchinningLarsen and Jytte Larsen is highly appreciated. There are of course many more names,too many to distinguish individually. So I would like to thank all the past and presentcolleagues at Radio Access Technology section, Aalborg University and Nokia SiemensNetworks for their friendly support.Special thanks to Francesco Calabrese and Guillaume Monghal, cherished friends,who have also made up a major part of my daily life, with whom I shared the entirejourney towards our PhD work. Further, I am grateful to my sister Amina Kaosar andthe extremely helpful bunch of friends, Oumer Teyeb, Danish Khan, Akhilesh Pokhariyal,Sanjay Kumar, Doa Idris, Basuki Priyanto, Muhammad Imadur Rehman, and Shashi Kantfor making my stay in Denamrk enjoyable.Finally, I would like to thank my family, whose love, support and encouragementhave accompanied throughout my life. They supported me in every possible way and theywere always beside me although they were so many thousand miles away. Words alonecan never express my gratitude.ixAbbreviations16QAM 16 Quadrature Amplitude Modulation3G Third Generation3GPP Third Generation Partnership Project64QAM 64 Quadrature Amplitude ModulationAC Admission ControlaGW Access GatewayAMBR Aggregate Maximum Bit RateAMC Adaptive Modulation and CodingAPG Average Path GainARP Allocation Retention PriorityATB Adaptive Transmission BandwidthAVI Actual Value InterfaceB3G Beyond 3GBCH Broadcast ChannelBE Best EffortBLEP BLock Error ProbabilityBLER BLock Error RateCAZAC Constant Amplitude Zero Auto-CorrelationCBR Constant Bit RateCC Chase CombiningCIR Carrier to Interference RatioCPICH Common Pilot ChannelCQI Channel Quality InformationCSI Channel State Informationxixii AbbreviationsdB DecibelDCH Dedicated ChannelDFT Discrete Fourier TransformDL-SCH Downlink Shared ChannelDRX Discontinuous ReceptionDSCH Downlink Shared ChannelE-DCH Enhanced Dedicated ChannelELIISE Efcient Layer II Simulator for E-UTRANeNode-B Evolved Node BEPC Evolved Packet CoreEPS Evolved Packet SystemE-UTRAN Evolved Universal Terrestrial Radio Access NetworkFD Frequency-DomainFDPS Frequency-Domain Packet SchedulingFPC Fractional Power ControlFTP File Transfer ProtocolGBR Guaranteed Bit RateGPRS General Packet Radio ServiceGPS Generalized Process SharingGSM Global System for Mobile CommunicationHARQ Hybrid Automatic Repeat reQuestHSDPA High Speed Downlink Packet AccessHS-DSCH High Speed Downlink Shared ChannelHSPA High Speed Packet AccessHSUPA High Speed Uplink Packet AccessIIR Innite Impulse ResponseIR Incremental RedundancyKPIs Key Performance IndicatorsL1 Layer 1 (physical layer)L3 Layer 3 (network layer)Abbreviations xiiiLA Link AdaptationLTE Long Term EvolutionMAC Medium Access ControlMBMS Multimedia Broadcast Multicast ServiceMCH Multicast ChannelMCS Modulation and Coding SchemeMIMO Multiple Input Multiple OutputMRC Maximal Ratio CombiningNRT Non-Real TimeOFDM Orthogonal Frequency Division MultiplexingOFDMA Orthogonal Frequency Division Multiple AccessOLLA Outer Loop Link AdaptationPAPR Peak-To-Average Power RatioPBCH Physical Broadcast ChannelPBR Prioritized Bit RatePCH Paging ChannelPDCCH Physical Downlink Control ChannelPDSCH Physical Downlink Shared ChannelPDN Packet Data NetworkPF Proportional FairPMCH Physical Multicast ChannelPRACH Physical Random Access ChannelPRBs Physical Resource BlocksPS Packet SchedulerPSD Power Spectral DensityPUCCH Physical Uplink Control ChannelPUSCH Physical Uplink Shared ChannelQCI Quality Class IdentierQoS Quality of ServiceQPSK Quadrature Phase Shift Keyingxiv AbbreviationsRACH Random Access ChannelRAD Required Activity DetectionRLC Radio Link ControlRNC Radio Network ControllerRRC Radio Resource ControlRRM Radio Resource ManagementRSCP Received Signal Code PowerRSRP Reference Signal Received PowerRSS Received Signal StrengthRSSI Received Signal Strength IndicatorRT Real TimeSAE System Architecture EvolutionSC-FDMA Single-Carrier Frequency Division Multiple AccessSCH Synchronization ChannelSINR Signal-to-Interference-plus-Noise RatioSNR Signal-to-Noise RatioSRS Sounding Reference SignalTD Time-DomainTDPS Time-Domain Packet SchedulingTTI Transmission Time IntervalTTT Time-to-TriggerTU Typical UrbanUE User EquipmentUL-SCH Uplink Shared ChannelUMTS Universal Mobile Telecommunications SystemVoIP Voice over Internet ProtocolWFQ Weighted Fair QueueingWCDMA Wideband Code Division Multiple AccessContentsAbstract vDansk Resum viiPreface and Acknowledgments ixAbbreviations xi1 Introduction 11.1 Preliminaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2 Long Term Evolution . . . . . . . . . . . . . . . . . . . ....</p>