Performance Evaluation of Interference Aware MMSE and Interference Suppression MMSE Techniques for A Cellular Distributed MU-MIMO System

Cellular distributed multi-user MIMO (MU-MIMO) is a system, in which a wide service area is divided into a number of base station (BS) coverage areas (cells), multiple user-clusters are formed by grouping neighborhood users together in each cell, and small-scale cluster-wise distributed MU-MIMO cooperative transmission/reception is performed in parallel. The use of cellular structure is to ensure the system scalability and the use of cluster-wise distributed MU-MIMO in parallel is to ensure reduced complexity spatial multiplexing of users in each cell. In such a system, the inter-cell interference and the inter-cluster interference are produced and limit the system capacity improvement achievable by distributed MU-MIMO. The inter-cluster interference can be suppressed by minimum mean square error (MMSE) pre/postcoding technique. So far, we have proposed interference aware MMSE (IA-MMSE) and interference suppression MMSE (IS-MMSE) techniques. The former considers the inter-cluster interference as an equivalent noise, while the latter takes the instantaneous channel correlation matrix of the inter-cluster interference into the MMSE weight vector. In this paper, we evaluate by computer simulation the uplink user capacities achievable with two MMSE techniques and show that the IS-MMSE provides higher user capacity than the IA-MMSE when compared at the same computational complexity.