Research on Interference Alignment Technique in Multi-cell Cooperative Systems Based on Poisson Point Process

In the multi-cell MIMO (Multiple-Input Multiple-Output) cooperative communication system, the performances of outage probability and network throughput of interference alignment applied by the cooperative Base Stations (BSs) and users are investigated when the locations of the BSs follow Poisson Point Process (PPP) distribution, and the analytical expressions of the above performances are derived under the conditions of perfect Channel State Information (CSI) and imperfect CSI, respectively. The monotonic relationships between the system performances and the cooperation parameters are also analyzed. The simulation analyses reveal that, under the condition of perfect CSI, the network throughput improves with the increase of BS density, the number of cooperative BSs and the number of antennas; under the condition of imperfect CSI, considering both the resource overhead of channel training and limited feedback and the channel distortion induced by quantized CSI, there exists an optimal number of BSs which can maximize the network throughput. When the number of antenna is small or the velocity of mobile user is not so high, more BSs are expected to participate into the cooperation, and when the number of antenna or the velocity of mobile user is large, the number of cooperative BSs should be appropriately reduced.