Multi-cell distributed interference cancellation for Co-operative Pico-cell clusters

Alternative wireless topologies, e.g., an underlay network of Pico-cells, are increasingly seen as being necessary to enhance capacity and coverage in next generation wireless systems. Such networks of closely-spaced base-sites have to contend with high interference issues, wherein interference mitigation via power control or interference co-ordination may not be sufficient. Capacity can be significantly enhanced by Co-ordinated Multi-Point (CoMP) techniques, which allow co-operative signal processing to jointly decode user´s signals, especially given fast communication links between the nodes. In this paper, we present a cooperative system design for the uplink of LTE for providing high capacity solutions in dense deployments. We propose non-linear receiver algorithms for inter-cell interference suppression and cancellation based on a decentralized multistage cancellation architecture using user-specific clustered Pico-cell antennas. An interference cancellation method acting on post-antenna combined signal is proposed to reduce the computational complexity of the receiver. The decoding latency inherent in multistage receivers is another key bottleneck, which is addressed in this paper by a method to predict the ACK/NACK status at the output of the multistage receiver before actually doing the cancellation. Simulation results for a dense stadium deployment of Pico-cells are presented that show significant capacity gains with the proposed approaches.