Trellis-coded pulse-position modulation for indoor wireless infrared communications

We analyze the performance of trellis-coded pulse-position modulation (PPM) on indoor, wireless infrared channels. We show that maximum-likelihood sequence detection (MLSD) of trellis-coded PPM is very effective in mitigating the multipath dispersion on such channels. We present code search results for high constraint-length, rate-2/3, 8-PPM and rate-3/4, 16-PPM codes. We provide bit-error rate curves and intersymbol interference power-penalties for MLSD of PPM with these codes, evaluated on ceiling-bounce channel models with delay spread per bit duration ratios of 0.01-0.3. Finally, we present Monte Carlo simulation results to verify our analysis.