In relay systems, the probability of errors occurring in the source-relay (S-R) link can be viewed as representing correlation between the source and the relay. This letter proposes a very simple iterative decoding te...
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In relay systems, the probability of errors occurring in the source-relay (S-R) link can be viewed as representing correlation between the source and the relay. This letter proposes a very simple iterative decoding technique, accumulator-assisted distributedturbo code (ACC-DTC) using 2-state (memory-1) convolutional codes (CC), where the correlation knowledge between the source and the relay is estimated and exploited at the destination.
In this paper, we propose a dynamic coded cooperation using multiple turbocodes in wireless relay networks where both relay and destination are equipped with a sensing device and the relay is assumed to determine aut...
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In this paper, we propose a dynamic coded cooperation using multiple turbocodes in wireless relay networks where both relay and destination are equipped with a sensing device and the relay is assumed to determine autonomously if it should cooperate or not. We first elucidate the fact that the puncturing patterns of the multiple turbocodes determine the achievable diversity order by deriving their pairwise error probabilities (PEP). This is followed by a derivation of a simple power detector at the destination that can estimate a precise duration of cooperation phase upon decoding information. Furthermore, we investigate the impact of process delay due to cognitive processing at the relay, which results in the loss of diversity gain, and propose a simple null padding as its countermeasure. Computer simulations show that our proposed approach is able to achieve a full diversity and the frame error rate (FER) performance superior to that of conventional cooperative communications that make use of turbo coding structure even in practical scenarios.
Wireless broadcasting systems employ multiple retransmissions to guarantee the correct reception of each packet. The traditional hybrid automatic retransmission request (HARQ) protocol retransmits one packet per slot....
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Wireless broadcasting systems employ multiple retransmissions to guarantee the correct reception of each packet. The traditional hybrid automatic retransmission request (HARQ) protocol retransmits one packet per slot. Hence, a large amount of retransmissions is required to correctly receive all the packets, which leads to low spectrum efficiency. In this paper, we propose a Network-coding-and-distributed-turbo-Coding-based type-III HARQ (NTC-HARQ) protocol, including an XORing Network Coding Combined (XNCC) retransmission strategy at the access node (AN) and a joint network-turbo decoding (JNTD) strategy at the user equipment (UE). Specifically, to reduce the overall number of retransmissions, lost packets of different UEs are network coding (NC) combined at the AN by utilizing the XNCC strategy. The soft information of the lost packet at each UE can be recovered from the received network-coded retransmission packet by using the proposed XORing soft network decoder. The recovered soft information of the UE's lost packet is combined with the local undecodable soft information of the same packet to form a distributedturbo code. A Chase-combining-based distributedturbo decoder is proposed to perform turbo decoding, which introduces coding gain and improves packet-error-rate (PER) performance. Theoretical analyses and simulation results show that the average-number-of-transmission performance of the proposed NTC-HARQ protocol outperforms that of the XNCC-based type-I HARQ protocol, the traditional NC-based HARQ protocol, and the JNTD-based protocol.
Estimation of a binary source using multiple observers, a variant of the so called Chief Executive Officer (CEO) problem, is considered. A low-complexity distributed Joint Source Channel Coding (D-JSCC) based on the P...
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Estimation of a binary source using multiple observers, a variant of the so called Chief Executive Officer (CEO) problem, is considered. A low-complexity distributed Joint Source Channel Coding (D-JSCC) based on the Parallel Concatenated Convolutional codes (PCCC) is implemented in a cluster of sensors in a distributed fashion. Convergence of the iterative decoder is analyzed by utilizing EXtrinsic Information Transfer (EXIT) chart technique to determine the convergence region in terms of the sensors observation accuracy and channel SNR, where the iterative decoder outperforms the non-iterative one. This leads to design of a bi-modal decoder that adaptively switches between the iterative and non-iterative modes in order to avoid inefficient iterative information exchange without compromising the resulting Bit Error Rate (BER). This adaptive decoding algorithm saves the computational power and decoding time by a factor of about 10 by avoiding unnecessary iterations.
In this paper, we analyze the block error rate (BLER) and bit error rate (BER) of soft decode-and-forward (SDF) using distributed turbo codes, which is proposed recently to mitigate error propagation caused by decodin...
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ISBN:
(纸本)9781424416448
In this paper, we analyze the block error rate (BLER) and bit error rate (BER) of soft decode-and-forward (SDF) using distributed turbo codes, which is proposed recently to mitigate error propagation caused by decoding error in the relay node. Union bound (UB) in fading channels is derived and compared with simulation results. In order to get tight bounds for block fading case, limit-before-average technique is used. Furthermore, we extend our analysis to the space-time cooperation framework. The analysis and simulation show that the derived bound is very tight.
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