Channel Coding for Energy Harvesting Communications Using Run Length Limited Codes

We propose a serially concatenated coding scheme to communicate over binary energy harvesting communication channels with additive white Gaussian noise (AWGN), and design explicit and implementable codes for both long and short block lengths. Run length limited (RLL) codes are used to induce the required nonuniform input distributions for both cases. We employ low density parity check (LDPC) codes for long block lengths, while for short block lengths, we utilize convolutional codes as outer error correction codes. We consider different decoding approaches for the two cases, i.e., an iterative decoder is used for the former while Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm over the product trellis of the convolutional and run length limited codes is used for the latter. We also extend our work to joint energy and information transfer for both cases since similar coding solutions can be employed. Numerical examples demonstrate that the newly optimized codes with an inner RLL code are superior to the optimal codes over standard AWGN channels for long block lengths. Our results also show that, for the short block length case, concatenated convolutional and RLL codes with higher minimum distances offer excellent performance.