Analysis of pilot symbol assisted modulation in fading channels using finite state Markov models

We present an analysis for channel state estimation and coherent data detection in pilot symbol assisted modulation (PSAM), which is based on the maximum a posteriori (MAP) criterion. The time varying fading channel is modelled as the finite state Markov channel (FSMC). The exact channel state estimation error probability is analyzed, using the forward recursion in the forward-backward algorithm. The effect of channel state estimation error probability on the receiver symbol error rate (SER) performance in an M-ary phase shift keying (PSK) scheme is formulated. The analysis is applied for different channel phase quantization levels and various pilot symbol numbers. The results indicate that BPSK SER performance is saturated with more than 8 to 16 levels of channel phase quantization. For a QPSK scheme, 16 levels of channel phase quantization are adequate. Moreover, the transmission of 3 consecutive pilot symbols achieves an acceptable SER performance.