Power-efficient coded modulation and precoding schemes for wireless infrared communications

We design new trellis codes based on multiple pulse-position modulation (MPPM) that offer high power efficiency. We randomly search for the optimal code that produces the trellis code with the largest minimum Euclidean distance. To verify our results, we derive an approximation for the minimum distance. We combine partial-response precoding with parallel decision-feedback detection to equalize and to decode the trellis codes. The performance of the proposed scheme is compared to linear equalization, decision feedback equalization, parallel decision-feedback detection, and super-state maximum-likelihood sequence detection. Together, the proposed trellis codes and precoding schemes are an effective solution to the signaling design problem, especially in the face of severe multipath dispersion