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Network-coded (NCed) automatic repeat request (ARQ) techniques have been shown to provide significant throughput improvements over basic ARQ systems in two-way wireless systems. Most results derived so far, however, used the assumption of no extra overhead. In practical systems, NCed-ARQ requires more information exchange between base-station and end-nodes, and therefore it is crucial to study the...
In this paper, we develop selective retransmission schemes for multiple-channel systems. The proposed schemes are selective automatic repeat request with fixed bandwidth (SARQ-FB), selective chase combining with fixed bandwidth (SCC-FB) and selective automatic repeat request with variable bandwidth (SARQ-VB). The main objective of the proposed schemes is to use the available power and bandwidth budget...
In this paper, decentralized heuristic access policies are designed for two secondary users (SUs) in an underlay cognitive radio network in which the PU employs Type-I Hybrid ARQ. Exploiting the redundancy in PU retransmissions, each SU receiver applies interference cancellation (IC) to remove a successfully decoded PU message in the subsequent PU retransmissions. There is no central control unit...
We introduce an optimisation problem to maximise the throughput of class of rateless codes subject to a delay constraint for a point to point erasure packet channel with delayed feedback. We show that this problem is convex. Using the formulation for point to point communication, we extend our approach to the communication of multiple unicast flows in a network.
Buffer-aided network coding (NC) has been proposed as an effective method to improve retransmission efficiency. In this way, the correctly received undecodable NC combined retransmission packets are waited in the buffer for a future network decoding opportunity rather than delete. However, existing buffer-aided approaches fail to consider the buffer status and the latest feedback in the next round...
We consider a communication system with energy harvesting at a receiver for which the processing energy is the bottleneck. We propose using hybrid automatic retransmission request (HARQ) with soft combining to reduce the processing energy and improve the throughput under limited receiver energy. In this protocol, the receiver keeps requesting additional redundancy in order to increase the gap between...
Hybrid automatic repeat request (HARQ) can make efficient and reliable transmission possible for radio communications. However, in the HARQ scheme, packet control information (PCI), such as HARQ block identifiers (HARQ block ids) in selective repeat ARQ (SR-ARQ), are required and the reduction of PCI overhead is an issue. In particular, type-II HARQ handles a large amount of PCI because it includes...
In this work, we analyze hybrid ARQ (HARQ) protocols used over independent block fading channels. We assume that the transmitter is unaware of the channel state information (CSI) at the moment of transmission but knows the statistics of the channel. We consider two scenarios with respect to the feedback received by the transmitter: (i) “conventional”, one-bit feedback carrying the message about the...
In this paper, two novel decoding methods are designed for two kinds of rateless codes: binary deterministic rateless (BDRC) codes and LT codes. The traditional decoding algorithms for the two kinds of codes discard the erroneous packets that may only contain few erroneous bits, which will causes the waste of bandwidth. The novel decoding methods adopt the packet combining technology to find the positions...
Hybrid Automatic Repeat Request is used as an error control and recovery mechanism in IEEE 802.16. Many different performance improvements over the standard error control mechanism have been proposed. One such improvement [1] considers the synergy between the MAC and PHY layers and proposes an adaptive fragmentation scheme, whereby the fragmentation is done only at the MAC layer at high bit error...
The various codes are used for the error detection and correction in the field of communication. Some are for the single bit error and some are for the multiple bits error. Reed-Muller algorithm realizes the ability of multiple bits error detection and correction. With the superior error correction capability, these codes have initiated wide scale interests in satellite communication, wireless communication,...
In this paper, we develop Prioritized Adaptive Code-Enhanced (PACE) link-layer protocol to achieve preferred data recovery order across connections, while maintaining stable and reliable data flow over a wireless network. We classify link-layer traffic arrivals into different priorities based on delay constraint and distortion associated with that traffic. We formulate the link-layer buffer as a multiclass...
In recent years, hybrid-automatic repeat request (ARQ) protocol has become one of the most popular packet transmission schemes. Hybrid-ARQ aims to combine the advantages of forward error correction codes with the traditional ARQ scheme to increase the reliability and throughput of the network. In this paper, we look at improving upon this performance for block fading channels (e.g., Rayleigh, Rician,...
Many popular wireless networking protocols, e.g., WiMAX and UMTS, use Hybrid-ARQ for error control. HARQ combines the retransmission mechanism of ARQ protocol with the forward error correction techniques to give a better bit error rate performance under adverse channel conditions. WiMAX standard suggests a multichannel stop-and-wait HARQ. If the number of errors exceeds the error correction capability...
Interference in wireless networks is one of the key capacity-limiting factors. Recently developed interference-embracing techniques show promising performance on turning collisions into useful transmissions. However, the interference-embracing techniques are hard to apply in practical applications due to their strict requirements. In this paper, we consider utilizing the interference-embracing techniques...
A novel iterative (turbo) receiver is introduced, suitable for orthogonal frequency division multiplexing (OFDM) employing quadrature amplitude modulation (QAM) and receiver diversity. The system operates over a double-selective channel and includes a carrier frequency offset (CFO). We propose a maximum a posteriori probability expectation-maximization (MAP-EM) receiver with a different EM parameter...
This paper presents hybrid type-II automatic repeat request (H-ARQ) for wireless wearable body area networks (BANs) based on ultra wideband (UWB) technology. It is shown that the improvement in performance in terms of throughput and error protection robustness is very significant. Thus, the proposed H-ARQ schemes can be employed and optimized to suit medical and non-medical applications. In existing...
Cognitive radio technology enables the coexistence of Primary (PUs) and Secondary Users (SUs) in the same spectrum. In this work, it is assumed that the PU implements a retransmission-based error control technique (ARQ). This creates an inherent redundancy in the interference created by primary transmissions to the SU. We investigate secondary transmission policies that take advantage of this redundancy...
This paper describes a system for the distribution of content over multicast and broadcast media that uses network coding techniques for concealing packet losses from the applications, improving the received Quality of Service. We propose a systematic network code designed for this purpose, analyze the performance of the code, comparing it with a standard approach based on random linear network coding,...
In this paper a hybrid automatic repeat request (HARQ) with turbo codes in OFDM system, and the differences hybrid ARQ methods designed for Turbo-coded transmissions on OFDM are presented. Two kinds of modified methods, one without ARQ and the other one are with HARQ: HARQ type-I and HARQ type-II. The latter scheme is based on a combination of the transmitted packets, just before the turbo-decoder...
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