Discrete-event simulation of coordinated multi-point joint transmission in LTE-Advanced with constrained backhaul

Inter-cell interference in LTE-Advanced can be mitigated using coordinated multi-point (CoMP) techniques with joint transmission of user data. However, this requires tight coordination of the eNodeBs, using the X2 interface. In this paper we use discrete-event simulation to evaluate the latency requirements for the X2 interface and investigate the consequences of a constrained backhaul. Our simulation results show a gain of the system throughput of up to 120% compared to the case without CoMP for low-latency backhaul. With X2 latencies above 5 ms CoMP is no longer a benefit to the network.