Construction of Adaptive Short LDPC Codes for Distributed Transmit Beamforming.

One of the challenges often faced with wireless communication systems is its limited range and data-rate. Distributed Transmit Beamforming (DTB) techniques are being developed to address these two issues to provide reliable connectivity from power-limited distributed users. This paper proposes an adaptive Low Density Parity Check (LDPC) coding scheme for the DTB system. The proposed scheme constructs powerful LDPC codes with varying code-rates and block-lengths. This feature of the proposed scheme allows the DTB system to optimise its system resources, improve throughput and communicate reliably under large variation of different channel environments. The performance of some of the codes constructed using the proposed scheme is evaluated and compared with the uncoded and other coded-DTB systems. The results obtained show large gains over the compared systems. The results also show that coding applied to the DTB system drastically reduces the minimum number of distributed transmit nodes required to achieve a target error-rate with the same energy per information bit to noise power spectral density.