Reducing CoMP control message delay in PON backhauled 5G networks

In 5G mobile communication systems, Coordinated scheduling (CS) is a Coordinated Multipoint (CoMP) technique exploited to improve the cell throughput by reducing the interference among contemporary transmissions at the cell edge. CS is based on coordinating the transmission scheduling decisions by exchanging scheduling information among the evolved NodeB (eNB) on the X2 interface. However, CS performance heavily depends on the time it takes the information to propagate among the eNBs (i.e., convergence time). This paper proposes a novel bandwidth allocation (BA) scheme which prioritizes the X2 traffic with respect to other traffic types when a TDM PON is used as 5G backhaul. Results show the impact of the proposed scheme when either Centralized Coordinated Scheduling (CCS) or Distributed Coordinated Scheduling (DCS) is utilized. In particular, results show that prioritizing X2 traffic over S1 traffic improves the convergence time. Moreover, CCS implementation is preferable when the number of eNBs-ONUs is large because of the lower convergence time and lower increase of the S1 traffic delay.