Distributed Space Time Coding for Wireless Two-Way Relaying

Muralidharan, Vijayvaradharaj T and Rajan, Sundar B (2013) Distributed Space Time Coding for Wireless Two-Way Relaying. In: IEEE TRANSACTIONS ON SIGNAL PROCESSING, 61 (4). pp. 980-991.

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Abstract

We consider the wireless two-way relay channel, in which two-way data transfer takes place between the end nodes with the help of a relay. For the Denoise-And-Forward (DNF) protocol, it was shown by Koike-Akino et al. that adaptively changing the network coding map used at the relay greatly reduces the impact of Multiple Access Interference at the relay. The harmful effect of the deep channel fade conditions can be effectively mitigated by proper choice of these network coding maps at the relay. Alternatively, in this paper we propose a Distributed Space Time Coding (DSTC) scheme, which effectively removes most of the deep fade channel conditions at the transmitting nodes itself without any CSIT and without any need to adaptively change the network coding map used at the relay. It is shown that the deep fades occur when the channel fade coefficient vector falls in a finite number of vector subspaces of, which are referred to as the singular fade subspaces. DSTC design criterion referred to as the singularity minimization criterion under which the number of such vector subspaces are minimized is obtained. Also, a criterion to maximize the coding gain of the DSTC is obtained. Explicit low decoding complexity DSTC designs which satisfy the singularity minimization criterion and maximize the coding gain for QAM and PSK signal sets are provided. Simulation results show that at high Signal to Noise Ratio, the DSTC scheme provides large gains when compared to the conventional Exclusive OR network code and performs better than the adaptive network coding scheme.

Item Type:	Journal Article
Publication:	IEEE TRANSACTIONS ON SIGNAL PROCESSING
Publisher:	IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Additional Information:	Copyright for this article belongs to IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, USA
Keywords:	Distributed space time coding;physical layer network coding;wireless two-way relaying
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	11 Mar 2013 11:32
Last Modified:	11 Mar 2013 11:32
URI:	http://eprints.iisc.ac.in/id/eprint/45996

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