The Method of Equalization Based on Iterative Interference Cancellation for SCCPM System

An improved iterative interference canceller (IC) for serially concatenated continuous phase modulation (SCCPM) is proposed. The classical IC uses the uniform probability distribution as input on the first iteration because the CPM soft-input soft-output (SISO) model can not provide the useful information at that time, so the ISI is not canceled at all and the performance of equalization is poor when the ISI is serious. In order to resolve the problem the proposed IC uses the priori probability of transmitted signal as input on the first iteration, which can cancel some ISI and improve the performance of equalization. Simulation results show that the proposed IC has the gain of 0.5 dB and 3.3 dB over the moderate ISI and is effective over serious ISI where the classical IC is ineffective.