Joint sequential decoding and noncoherent multiuser detection for synchronous signaling over a flat fading channel

This paper considers the problem of joint multiuser detection and decoding of data transmitted over a frequency nonselective Rayleigh fading channel, where the detection is performed without previous knowledge of the channel coefficients. Both detection and decoding are carried out jointly by means of a sequential decoder. We derive a metric matched to the above problem which is based on the well-known Fano (1963) metric and discuss its properties. Using computer simulation, we evaluate the performance of a sequential decoder that uses this metric in conjunction with the stack algorithm. Our simulation results show that the proposed algorithm outperforms a receiver that uses optimum multiuser detection and optimum soft decision decoding as two separate steps, however at the cost of even larger time complexity.