Concatenated space-time trellis codes with optimal puncturing patterns

The performance of space-time trellis codes (STTCs) serially concatenated with convolutional codes and Bose-Chaudhuri-Hocquenghem codes is evaluated over quasistatic Rayleigh fading channels. The STTCs are used as inner codes since they provide diversity owing to their multi-antenna nature. The loss in spectral efficiency incurred due to the added redundancy from the outer codes is dealt with by constructing punctured STTCs. Optimal puncturing patterns are obtained based on the required rate of the code that provides full diversity and the best coding gain. This is performed for two-antenna, four-PSK STTCs with a varying number of transitional states. Results show low performance loss when high-state STTCs are punctured but high performance loss in a serially concatenated system. A trade-off is therefore obtained by deploying a concatenated system with a low-state punctured STTC against a high-state punctured STTC that suffers the least performance loss when punctured.