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 28 for “"automatic repeat request"”.
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New hybrid automatic repeat request (HARQ) combining with space time block coding (STBC) in invariant and variant fading channel
Hybrid Automatic Repeat reQuest (HARQ) combining for space time block coding Multiple Input Multiple Output (MIMO) system consisting of N transmit antennas and M receive antennas (NxM) in a time invariant channel and in a time varying channel is proposed and its performance is analyzed. Based on …
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New hybrid automatic repeat request (HARQ) scheme for 4x4 MIMO system, based on the extended alamouti quasi-orthogonal space-time bloc coding (Q-STBC), in invariant and variant fading channel
A new Hybrid Automatic Repeat reQuest (HARQ) combining scheme for a 4x4 Multiple Input Multiple Output (MIMO) system in invariant and variant fading channel conditions is proposed and analized. Based on the Extended Alamouti Quasi-orthogonal Space-Time Block Coding (Q-STBC), the use of the …
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The application of forward error correction techniques in wireless ATM
… of forward error correction coding schemes, automatic repeat request schemes and interleavers to combat the impact of bit errors on the performance of the link. The following error control strategies were considered : 1. A stand alone fixed rate Reed-Solomon encoder/decoder with automatic …
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Retransmission strategies for moving networks over ricean fading channels
… retransmission protocols based on Hybrid Automatic Repeat reQuest (HARQ) for moving networks over Ricean fading channels has been considered. The scenario of interest consists of one receiver traveling at a given speed while connected to a wireless network based on OFDM (e.g., WiMax) …
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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 the …
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Coding performance on satellite channels using AX.25 protocol
… are employed. In packetized 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 …
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Resource Allocation for Interference Management in Wireless Networks
… a jammer mitigation framework through an automatic repeat request protocol. The other one utilizes power and, following a game-theoretic framework, employs a defense strategy against jamming based on a strategic power allocation. Superior performance of all of the proposed mitigation …
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Implementation and evaluation of various stop and wait type II hybrid ARQ schemes for mobile radio
… of various Stop-and-Wait (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 …
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Error Control in Wireless ATM Network
… in lower layers under ATM transport 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 …
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Performance analysis of star architecture packet-switched VSAT network using roll-call polling multiple access scheme
… Data Link Control or HDLC, and go-back-N Automatic Repeat Request, for error control. The network is a VSAT packet-switched network, that carries out its communications task on a Time Division Multiplexing (TDM) satellite channel. This research consists of three major parts. First, the …
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Optimum Design of Spectral Efficient Green Wireless Communications
… systems. Second, the optimum designs of automatic repeat request (ARQ) and hybrid ARQ (HARQ) systems are performed to by using the EE and SE as design metrics. Specifically, a new metric of normalized EE, which is defined as the EE normalized by the SE, is proposed to achieve a balanced …
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Rateless and rateless unequal error protection codes for Gaussian channels
… a rateless code to two different forms of hybrid automatic repeat request (HARQ), namely Chase combining HARQ and incremental redundancy HARQ. We find that the rateless codes compare favorably to both forms of HARQ. In addition, we develop a code that has both rateless and unequal error protection …
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Performance analysis of star architecture packet-switched VSAT networks using random code division multiple access
… of a traffic originating from the VSAT’s, the Automatic Repeat Request (ARQ) technique used for error control is the Stop-and-Wait (SW) protocol. It is used as a retransmission strategy in both the Asynchronous Time Division Multiplexing (ASTDM) and the ALOHA DS-CDMA channels.
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Fountain codes for the wireless Internet
… receive antennas is proposed. Finally, A Hybrid Automatic Repeat reQuest (H-ARQ) SLT coded modulation scheme is designed in this thesis, where SLT codes are used both for correcting erroneous bits and for detecting as well as retransmitting erroneous Internet Protocol (IP) based packets. …
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Channel-predictive link layer ARQ protocols in wireless networks
… link layer protocols. One 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 …
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Implementation of Parallel and Serial Concatenated Convolutional Codes
… criteria. Third, a new type-II code combining automatic repeat request (ARQ) technique is introduced which makes use of the related PCCC and SCCC. Fourth, a new code-assisted synchronization technique is presented, which uses a list approach to leverage the simplicity of the correlation …
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ARQ protocol for joint source and channel coding and its applications
… a joint source and channel 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. …
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ARQ Techniques for MIMO Communication Systems
… over single antenna communications. 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 …
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Analytical Modelling of Scheduling Schemes under Self-similar Network Traffic. Traffic Modelling and Performance Analysis of Centralized and Distributed Scheduling Schemes.
… Processor Sharing (GPS) schemes, and the Automatic Repeat reQuest (ARQ) forward error control discipline in the presence of self-similar traffic. Most recently, research on the innovative Cognitive Radio (CR) techniques in wireless networks is popular. However, most of the existing …
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Non-orthogonal random waveform based multiuser communications
… 4 and they are combined with a practical Hybrid Automatic Repeat reQuest (HARQ) system in Chapter 5.<br/>In the cellular system scenario presented in Chapter 3, we discuss three design tradeoffs ofMulti-Carrier Interleave Division Multiple Access (MC-IDMA) with the aid of EXtrinsic …
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