Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 46 for “"ARQ"”.
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ARQ Techniques for MIMO Communication Systems
… Traditional automatic-repeat-request (ARQ) techniques developed for single-input single-output (SISO) communication systems have to be modified in order to be employed in MIMO communication systems. In this dissertation, we propose and analysis some ARQ techniques for MIMO communication …
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Channel-predictive link layer ARQ protocols in wireless networks
… prominent approach is Automatic Repeat Request (ARQ) protocol. The traditional ARQ protocols attempt to recover the erroneously transmitted frames by retransmitting those frames, regardless of the channel state. Since this channel state unaware behaviour may cause unnecessary retransmissions, …
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Performance analysis of collaborative hybrid-arq protocols over fading channels
… Among cooperative schemes, Collaborative ARQ transmission protocols, prescribing cooperation only when needed, i.e., upon erroneous decoding by the destination, emerge as an interesting solution in terms of achievable spectral efficiency. In this thesis, an information theoretical approach …
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Packet data communications over coded CDMA with hybrid type-II ARQ
… into three parts; (1) CDMA with hybrid FEC/ARQ in deterministic environment, (2) CDMA with hybrid FEC/ARQ in random access environment and (3) an implementation issue on turbo decoding. As a preliminary, the performance of CDMA with hybrid FEC/ARQ is investigated in deterministic …
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ARQ protocol for joint source and channel coding and its applications
… coding that suits Automatic Repeat Request (ARQ) application and applies it to packet switching networks. Following aspects of the proposed joint source and channel coding approach will be presented: The design of the proposed joint source and channel coding scheme. The approach is based on a …
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A queueing analysis of a buffered block-selective S-ARQ protocol
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.
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Hybrid ARQ with parallel and serial concatenated convolutional codes for next generation wireless communications
… by incorporating these schemes in a hybrid FEC-ARQ environment. Beginning with an overview of wireless communications and the various ARQ protocols, the thesis provides an in-depth explanation of convolutional encoding and Viterbi decoding, turbo (PCCC) and serial concatenated convolutional …
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Design of an ARQ/AFEC link in the presence of propagation delay and fading
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.
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Practical packet combining for use with cooperative and non-cooperative ARQ schemes in wireless sensor networks
… include cooperative communications and hybrid-ARQ schemes which have been shown to be of major benefit for wireless communications. Using the packet combining scheme developed in this thesis more than an 85% reduction in energy costs are possible over previous, similar approaches. Both …
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Implementation and evaluation of various stop and wait type II hybrid ARQ schemes for mobile radio
… (SW) Type II Hybrid Automatic Repeat reQuest(ARQ) strategies. The modulation scheme utilized is the North American digital cellular standard known as 7r/4—shift DQPSK. The general Complementary Punctured Convolutional (CPC) SW Type II ARQ scheme is presented and numerically analyzed in both an …
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Sistema nervoso enterico e scrapie sperimentale in ovini di razza sarda con diversa suscettibilità genetica nei confronti della malattia
… recanti diversi polimorfismi del gene Prnp (ARQ/ARQ, ARQ/AHQ, ARQ/ARR, ARR/ARR). I suddetti animali, infettati per os all’età di 8 mesi con un ceppo di Scrapie precedentemente caratterizzato nel topo, sono stati sacrificati mediante eutanasia a determinati intervalli di tempo post-infezione …
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Attachment, childhood adversity, emotional problems and personality disorder in offenders with mild intellectual disability
… of the ‘Adapted Relationship Questionnaire’ (ARQ). To test construct validity and reliability the ARQ and the RQ were administered to 60 university student participants. Participants rated each questionnaire with regard to retrospective childhood attachment, 41 additional participants filled …
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Hybrid Channel Coding for Error-Sensitive Class on DS-CDMA Air Interface
… a technique for hybrid channel coding for ARQ (Automatic-Repeat-reQuest) protocol and FEC (Forward Error Correction) scheme that can reduce the error rate significantly. Each of ARQ protocol and FEC scheme gives rise to long latency and significant complexity, respectively, for obtaining …
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Error Control in Wireless ATM Network
… layer. Automatic Repeat reQuest schemes (ARQ) and Forward Error Correction (FEC) have been widely used for reliable data transmissions. However, the current existing ARQ schemes can potentially introduce unbounded delay in high error rate environments like W-ATM network due to the lack of …
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Interactions between TCP and link layer protocols on mobile satellite links
… correlated packet loss. The use of a link layer ARQ protocol can improve TCP performance by insulating TCP from data. loss. However, the interactions between TCP and link layer protocols are not well understood. This thesis describes an emulation-based study of a mobile satellite link that …
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Coding performance on satellite channels using AX.25 protocol
… transmission, automatic-repeat-request (ARQ) schemes and error correcting codes have been employed. Currently a combination of both is not employed by the AX.25 protocol. The purpose of this project is to determine which error correcting code should be combined with ARQ to provide the …
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Synthesis and Evaluation of the Aristotelia Alkaloids at the α3β4 Nicotinic Acetylcholine Receptor
… be found in the natural product aristoquinoline (ARQ), which is both moderately selective and potent at the α3β4 nAChR. This dissertation investigates the pharmacological utility of the α3β4 nAChR by developing two complementary assays to evaluate novel antagonists based on the ARQ scaffold: a …
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Performance enhancements in next generation wireless networks using network coding : a case study in WiMAX
… the performance of the architecture to that of HARQ and ARQ mechanisms. The performance measures are packet loss percentage, throughput and file transfer delay. The experiments use the Global Environment for Network Innovations (GENI) WiMAX platforms. UDP traffic considered; Iperf and UDP based …
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Adaptive Protocols to Improve TCP/IP Performance in an LMDS Network using a Broadband Channel Sounder
… and link layer automatic retransmission request (ARQ) to improve network and transport layer performance. Using a simulation model developed in OPNET, we determine the effects of different data link layer protocol configurations on TCP/IP throughput and end-to-end delay using a Rayleigh fading …
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Differential Radio Link Protocol: An Improvement To Tcp Over Wireless Networks
… differentially with respect to FEC coding and ARQ schemes. Specific cases of FEC and ARQ strategies are then considered and it is shown qualitatively as how the differential treatment of frames can improve the performance of the RLP and in effect that of TCP over wireless networks.
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