摘要：System throughput and resource utilization can be improved in ultra-dense networks (UDN) by deploying a large number of small base stations. However, base stations are very close in UDN, which will cause serious interference between base stations. To solve this problem, coordinated multi-point (CoMP) has been improved, which has the ability to reduce inter-cell interference and to improve data rate. However, the complexity of cooperation among all cells is very high. Therefore, it is necessary to construct small-size cooperation clusters. This article analyzes one of the key challenges of CoMP application in UDN—optimal CoMP clustering. Firstly, the background knowledge of CoMP is introduced. Secondly, we focus on the classification and summarization of the latest achievements in clustering research and the objective and challenges faced in the design of CoMP clusters. Finally, the future research directions and potential methods of CoMP clustering are discussed.
