Optimization of Coverage and Throughput in Single-Cell eMBMS

Multimedia Broadcast/Multicast Service (MBMS) based on point-to-multipoint (p-t-m) radio transmission was introduced by 3GPP to deliver broadcast service to a group of user equipments (UEs) in a cellular system. As a broadcast system with uplink feedback, its performance is limited by UEs in poor connections. To utilize the limited radio resource more efficiently, a simple but effective mechanism is proposed to improve the system throughput by sacrificing those UEs that are expensive to cover, which means the cost of this improvement is coverage degradation. We set a threshold for the SINR of UEs, and uplink feedback from UEs with G-factor lower than the threshold will be discarded in packet scheduling and link adaptation. Compared with other methods to increase the throughput, this mechanism has two advantages. First, the coverage can be exactly controlled by adjusting the threshold. Second, much higher throughput gain can be achieved for the same cost. Simulation results show that throughput will be increased by 22% with reasonable coverage degradation when there are 10 UEs per sector. Larger gains can be achieved with more UEs per sector.