List Detection for Overloaded Receivers with a Linear Array

We consider an overloaded wireless multiuser communication system where the number of transmitters exceeds the number of receive antennas. Each user transmits data through a single antenna to a receiver with an M-element uniform linear array. The received signals are combined using maximum ratio diversity combining. Severe co-channel interference (CCI) occurs in such a system due to multiple co-channel users. We present an iterative parallel multiuser detector with list feedback of the best estimates to separate and detect the user symbols. CCI is estimated in the detector using a novel list-based parallel interference cancellation scheme. Simulations show that our algorithm approximates joint-maximum likelihood detection at lower complexity and is well suited for practical application.