Efficient Multi-Cell Clustering for Coordinated Multi-Point Transmission with Blossom Tree Algorithm

Coordinated multi-point(CoMP) transmission clustering schemes could provide significant gains of system performance, such as throughput and cell-edge user data rates. Due to limitations of the backhaul communication and signal processing capability of base stations(BSs), the intrinsic problem of CoMP is that the selection of which BSs shall cooperate as only a few of BSs can be grouped in a cluster. However, approximating the theoretical performance bound of this clustering problem in CoMP at present is seldom discussed due to its inherent combinatorial complexity. In this paper, a novel efficient multi-cell clustering scheme based on blossom tree algorithm is proposed for cellular networks, incorporating CoMP with two cells in each cluster. With blossom tree algorithm, the proposed scheme can find out the optimal clustering strategy and help the CoMP transmission reach its theoretical performance bound on data rate in real-time computing(milliseconds in MATLAB simulation for one clustering). The simulation results show that our proposed method outperforms the existing dynamic greedy method in terms of cell edge users' average achievable data rate. Besides, it can also maintain high performance when extended to larger clusters in that with 4-cell clustering, the proposed method can reach 23.8% higher data rates than dynamic greedy method.