Iterative co-channel interference cancellation in narrowband mobile radio systems

In this paper, co-channel interference cancellation using iterative subtraction is proposed for narrow-band QPSK systems. Signal separability is obtained using both the relative timing delay between signals and the decoded bits output from the channel decoder. Cancellation after decoding results in more reliable signal subtraction, at the expense of interleaving delay. Simulation results show that a small number of iterations is required when ideal channel knowledge is assumed. Soft subtraction, where the estimated values are weighted with some reliability measure, leads to significant C/I gains for both coded and uncoded bits.