Distributed Iterative Detection With Reduced Message Passing for Networked MIMO Cellular Systems

This paper considers base station cooperation (BSC) strategies for the uplink of a multiuser multicell high-frequency reuse scenario where distributed iterative detection (DID) schemes with soft/hard interference cancelation (IC) algorithms are studied. The conventional distributed detection scheme exchanges soft-symbol estimates with all cooperating BSs. Since a large amount of information needs to be shared via the backhaul, the exchange of hard bit information is preferred; however, performance degradation is experienced. In this paper, we consider a reduced message passing (RMP) technique in which each BS generates a detection list with the probabilities for the desired symbol that are sorted according to their values in a decreasing order. The network then selects the best detection candidates from the lists and conveys the index of the constellation symbols (instead of double-precision values) among the cooperating cells. The proposed DID-RMP achieves intercell interference (ICI) suppression with low backhaul traffic overhead compared with the conventional soft bit exchange and outperforms previously reported hard/soft information exchange algorithms.