Combined zeroforcing with wideband beamforming for interference mitigation in cooperative cellular radio networks

Cooperative multipoint transmission (CoMP) in cellular systems is a widely discussed topic for future cellular networks. A main challenge therein is the limited size of practical realizable cooperation areas that entails many strong interfering cells in adjacent cooperation areas. This has been partly overcome by our so called partial CoMP concept, presented on several opportunities in 2010. Now, as further improvement, the so called `tortoise concept´ is proposed in this article. This is essentially an interference shaping method, realized with a three-dimensional wideband beamforming to minimize interference between cooperation areas. On top of the wideband beams, a central joint preprocessing cancels interference within the CA. This results in a strong mitigation of the total interference power with large performance gains.