ASE analysis adaptive pilot symbol assisted modulation with imperfect CSI

Adaptive modulation requires knowledge of channel state information (CSI) at the receiver by inserting pilot symbols in the transmitted signal. In This paper we focuses on the Adaptive Coded Modulation (ACM) system, where the data symbols and power allocation variable are optimized. The pilot spacing and power allocation are adaptively changed in an optimal way according to the conditions channel. We take into consideration the channel estimation error at the receiver and channel prediction error at the transmitter. The average spectral efficiency (ASE) performance of the suggested system is analyzed.