An adaptive soft-output receiver in space-time coding with continuous phase modulation

Space-time coding has shown great promise for digital transmission in wireless communication links, especially when the channel response Is known at the receiver. Combined with continuous phase modulation (CPM), better bandwidth and power efficiency can be obtained. But without the perfect channel state information, the high performance of space-time CPM system can be greatly degraded due to the channel estimation errors. In this paper we present an adaptive soft algorithm which per-forms joint channel estimation and data detection for space-time CPM system. Properly designed pilot symbols are inserted at the very beginning to give a good initial estimate of the channels. This soft demodulator is further applied to the Interleaved space-time CPM system to yield better performance with moderate complexity. Simulation results show that the receiver can often achieve near-coherent performance in quasi-static fading as well as in relatively fast fading.