Date Added: Sep 2012
Physical-Layer Network Coding (PLNC) allows two remote terminals to exchange information in two time slots via a half-duplex relay. In this paper, the authors consider PLNC in UnderWater Acoustic (UWA) two-way relay networks, with particular attention on the recovery of the network-coded codeword at the relay. Considering multiple paths in UWA channels with large delay spreads and temporal variations, Orthogonal-Frequency Division-Multiplexing (OFDM) is used as an underlying modulation. Distinct from existing works which mainly focus on the flat-fading channel and the non-iterative PLNC decoding, they investigate three iterative receivers at the relay in doubly-selective UWA channels.