Design of randomized space-time block codes for amplify-and-forward cooperative relaying

Cooperation diversity schemes employing distributed space-time block coding (STBC) techniques have been proposed for wireless networks to increase system capacity and coverage even when each node is only equipped with a single antenna. Capitalizing on randomized STBC, a decentralized coding method that has been developed for decode-and-forward relaying, a cooperative communication protocol is proposed for amplify-and-forward relays, which has three distinguishing features that make it fully decentralized: (i) each relay operates in a completely autonomous fashion; (ii) coherent decoding is carried out at the destination without knowing the number of cooperating nodes and the relaying parameters; (iii) maximum likelihood decoding at the destination can be implemented on a symbol-by-symbol basis in the case of full-rate orthogonal STBC. Numerical results are provided to highlight the effectiveness of the proposed scheme in comparison with previously-proposed competitive alternatives.