Energy efficient dynamic cooperating set planning for CoMP in LTE/LTE-A systems

Coordinated Multi-Point (CoMP) is considered as one of the most important techniques in 3GPP LTE/LTE-A. In CoMP, several base stations can be grouped together to form the cooperating set, where the cooperating set is used to improve the system throughput as well as the throughput of cell edge users. Most of the studies discussed how to relieve the overload condition or maximize the system throughput by exploiting CoMP. In these studies, static cooperating set is adopted, i.e., the size of the cooperating set is fixed. Different from previous studies, this paper provides a complete discussion by considering both off-peak hours and overload conditions. In off-peak hours, we try to save the transmit power of base stations and utilize the idle radio resource to achieve energy-efficient green communications while guarantee users' service quality. On the contrary, when big activities occur with gathered crowds or during the peak hours, we propose to dynamically form the cooperating set according to the actual traffic demand condition and adapt the transmit power of base stations, so that the system can effectively offload the traffic demand to the member cells with free radio resource in the cooperating set. Our proposed approach is a decentralized-based method, which avoids excess computing being executed in a base station. Simulation results show that our proposed method achieves the best system throughput, radio resource utilization, and energy efficiency in all schemes.