Network MIMO with reduced backhaul requirements by MAC coordination

We consider the problem of network coordination for reducing the intercell interference. Under full coordination of all bases in the network, interference can be reduced significantly at the cost of significant additional backhaul overhead. We propose to lower the backhaul requirements by allowing coordination over limited clusters of bases. Using the scheduler requirements and channel estimates, a central unit jointly forms the clusters of coordinated bases, selects the users and calculates the beamforming coefficients and the power allocations. Compared to a system with full coordination across the entire network, the proposed technique achieves a significant fraction of the full-coordination performance while significantly reducing the backhaul requirements.