System Level Modeling and Optimization of the LTE Downlink

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3. Physical Layer Modeling and LTE System Level SimulationThe paper presents (among other results) LTE CLSM system level simulation resultsfor an uncorrelated 4×2 antenna configuration in a well-defined scenario, describedin Table 3.7.Table 3.7.: Scenario parameters employed for comparison with the results in [107].Carrier frequency2 GHzChannel bandwidth10 MHzCell layout Hexagonal grid, 19 sites, 3 cells/siteAntenna pattern70 degree, 14 dBiInter-site distance500 mTransmission power46 dBmPathloss128.1 + 37.6 log 10 (r)Penetration loss20 dBShadow fading σ8 dBShadow fading correlation 0.5 (inter-site), 1.0 (intra-site)Channel modelITU-T Typical UrbanAntenna configuration 4×2Transmit modeCLSMSchedulingProportional FairUEs/cell 10Deviations are actually expected, caused by differences in implementation of channelmodels, receiver models, link adaptation, and link-to-system interfaces [106]. Regrettably,an in-depth analysis of the causes of the deviations is not possible due tothe closed nature of the tools employed to generate the results in [107]. However,when comparing the deviation between the two ecdf curves shown in Figure 3.21,we can state that the deviations is in the same order of magnitude as those acceptedfor use in LTE standardization for the Single-Input Multiple-Output (SIMO) case.50
4. Extensions to the L2S Model4. Extensions to the L2S ModelThis chapter details extensions to include Hybrid Automatic Repeat reQuest(HARQ) and channel estimation errors, both aiming at more realistic modelingcapabilities of LTE systems and extending the L2S model described in Chapter 3beyond its basic capabilities.These two extensions apply to different parts of the L2S model. The HARQ modelapplies to the link performance model, described in Section 3.1.2, while the channelestimation errors applies to the link quality model only, which is described inSection 3.1.1.4.1. Hybrid ARQHARQ is part of the LTE MAC layer and provides retransmission capabilities aimedat improving link reliability. It consists of the retransmission of erroneously-receivedTBs and a joint decoding of the received retransmissions. It is implemented in therate matching module, which also adjusts the rate matching target code rate, asmentioned in Section 2.2.3. The rate matching module is capable of, for a giventarget code rate, generating up to four versions of a TB. The different TB versions,indicated in the LTE standard by a redundancy version index, denoted as rv idx(rv 0 , . . . , rv 3 ), and when possible composed of a different subset of the original turboencodedbits, are combined at bit level and jointly decoded once received.4.1.1. LTE HARQAfter turbo encoding (see Section 2.2.3), the rate-1/3-encoded bits, consisting ofsystematic and parity bits, are placed in a circular buffer, from which the bits for51
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DissertationSystem Level Modeling a
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I hereby certify that the work repo
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KurzfassungDie vorliegende Arbeit p
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ContentsContents1 Motivation and Sc
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Page 17 and 18: 1. Motivation and Scope of Work1. M
Page 19 and 20: 1. Motivation and Scope of Worklaye
Page 21 and 22: 1. Motivation and Scope of Workperf
Page 23 and 24: BibliographyThe combined throughput
Page 25 and 26: 2. 3GPP Long Term Evolution2. 3GPP
Page 27 and 28: 2. 3GPP Long Term Evolutionup to 30
Page 29 and 30: 2. 3GPP Long Term EvolutionNAS proc
Page 31 and 32: 2. 3GPP Long Term Evolutionchannel
Page 33 and 34: 2. 3GPP Long Term EvolutionSince th
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Page 37 and 38: 2. 3GPP Long Term EvolutionTable 2.
Page 39 and 40: 3. Physical Layer Modeling and LTE
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Page 69 and 70: 4. Extensions to the L2S Model4.1.2
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Page 101 and 102: A. SNR-independence of the CLSM Pre
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Page 109 and 110: C. Taylor Expansion of the ZF MSEC.
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Page 113 and 114: D. Evaluation of Multi-User GainD.
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Abbreviations and AcronymsAbbreviat
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Abbreviations and AcronymsKPILLRL2S
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Abbreviations and AcronymsU-PlaneUT
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Abbreviations and AcronymsBibliogra
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Abbreviations and Acronymsdescripti
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Abbreviations and Acronyms[69] Tech
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Abbreviations and Acronymsfemto cel
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Abbreviations and Acronyms[134] Z.
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System Level Modeling and Optimization of the LTE Downlink

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