Collaboration alignment in distributed interference management in uplink cellular systems

We consider a cellular wireless system including several interfering multi-user multi-antenna uplink channels, where the base station of each cell has to locally recover the messages of its corresponding users. We use a linear Wyner model, where each base station experiences interference only from the users in the two neighboring cells. Each base station is connected to the two nearby base stations through a backhaul link. The objective is to achieve the maximum degrees of freedom per cell, with minimum aggregated load in the backhaul. We propose a successive cooperative alignment scheme, in which each base station forms backhaul messages by combining the previous received backhaul messages with the received signals at its wireless terminal. By some alignment schemes in signaling over wireless links as well as developing proper messages over backhaul links, each base station can help the neighboring base stations to peel off the aggregated interference with minimum help. This is done without propagating interference throughout the network. In this conference paper, we focus on linear one shot schemes and prove the optimality of the proposed scheme, in a robust set-up for a system with two antennas per base station and two users per cell, where each user is equipped with two antennas.