Distributed turbo coding with hybrid relaying protocols
Distributed turbo coding with hybrid relaying protocols
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DOI：
10.1109/pimrc.2008.4699424
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发表时间：
2008-12
期刊：
影响因子：
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通讯作者：
Yonghui Li;B. Vucetic;Jinhong Yuan
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文献类型：
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作者：
Yonghui Li;B. Vucetic;Jinhong Yuan
分布式Turbo编码（DTC）已被证明是一种有效的编码方案，以接近无线中继网络的容量。然而，大多数现有的直接转矩控制方案只考虑具有单个中继节点的中继网络，并假设中继可以进行无错误解码，我们称之为完美的直接转矩控制方案。在本文中，我们考虑了一个一般的2跳中继网络与任意数量的中继和设计DTC这样的网络时，考虑到不完美的解码在每个中继。我们提出了一个广义分布式涡轮编码（GDTC）方案与混合中继协议，这样的中继网络。在每次传输中，基于中继器是否能够正确解码，每个中继器被包括到两个中继器组中的一个中，这两个中继器组被称为解码和转发（decode and forward，DRB）中继器组和放大和转发（amplify and forward，AAF）中继器组。其中，AAF中继组中的每个中继将接收到的信号进行解码、交织、重新编码并转发到目的地，而AAF中继组中的每个中继将接收到的信号放大并转发到目的地。在目的地，从在AAF中继组中的中继发送的所有信号被组合成一个信号，并且在AAF中继组中的所有信号被组合成另一个信号。这两个信号形成广义DTC码字。理论分析和仿真结果表明，与纯AAF中继的分布式编码相比，所提出的GDTC方案不仅可以获得DTC中继组的编码增益，而且可以克服传统DTC方案中中继解码不完善所带来的错误传播的不利影响.随着信噪比的增加，它也接近于理想的DTC。
Distributed turbo coding (DTC) has been shown to be an effective coding scheme to approach the capacity of a wireless relay network. However, most of existing DTC schemes only consider a relay network with single relay node and assume that relay can perform an error free decoding, which we refer to as a perfect DTC scheme. In this paper, we consider a general 2-hop relay network with an arbitrary number of relays and design the DTC for such a network when taking into account imperfect decoding at each relay. We propose a generalized distributed turbo coding (GDTC) scheme with hybrid relaying protocol for such relay networks. In each transmission, based on whether relays can decode correctly or not, each relay is included into one of two relay groups, referred to as a decode and forward (DAF) relay group and an amplify and forward (AAF) relay group. Each relay in the DAF relay group decodes the received signals from the source, interleaves, re-encodes and forwards it to the destination, while each relay in the AAF relay group amplifies the received signals and forwards it to the destination. At the destination, all signals transmitted from the relays in the DAF relay group are combined into one signal and that in the AAF relay group are combined into another signal. These two signals form a generalized DTC codeword. Theoretical analysis and simulation results show that the proposed GDTC scheme benefits from a significant coding gain contributed from the DTC relay group compared to the distributed coding with pure AAF relaying and simultaneously overcome the detrimental effects of error propagation due to the imperfect decoding at relays in the conventional DTC schemes. It also approaches the perfect DTC as the signal to noise ratio (SNR) increases.