Backhaul Traffic Minimization under Cache-Enabled CoMP Transmissions over 5G Cellular Systems
Ya-Ju Yu, Wei-Chieh Tsai, Ai‐Chun Pang · 2016
Joint transmission (JT), an attractive coordinated multipoint (CoMP) downlink transmission technique, is used to increase cell-edge user throughput, but has to distribute the same user data to multiple base stations termed a JT cluster, thus leading to a huge burden on backhaul bandwidth. Therefore, recent studies considered caching user data at the base stations to reduce the backhaul bandwidth consumption. However, we observe that even with the caches at the base stations, JT clustering decisions, without considering the data caching, cannot efficiently use the data in the caches and will result in unnecessary backhaul data traffic. In this paper, we study the joint transmission clustering problem with the consideration of data caches at the base stations. The objective is to minimize the backhaul data traffic while each user's data rate requirement can be satisfied under the limited radio resource blocks. Then, considering the cache effect, we formulate the target problem and propose an algorithm to solve this problem. The simulation results agree our observation and show that compared with a JT clustering algorithm, our proposed algorithm can significantly reduce more backhaul data traffic.