Coordinated scheduling and network architecture for LTE Macro and small cell deployments

Coordinated Multi-Point (CoMP) transmission has been recognized as a primary method of further enhancing the downlink spectral efficiency of LTE Rel-10. A series of air interface enhancements have been made in LTE Rel-11 to support CoMP with Ideal Backhaul (IB), but the support of CoMP using Non-Ideal Backhaul (NIB) was not considered in Rel-11. Recently, 3GPP evaluated CoMP performance gains with non- ideal backhaul and currently considering the necessary signaling to support inter-eNB CoMP. In this study, two types of network architecture are considered, namely i) the current distributed architecture and ii) the centralized architecture with a new node/entity to enable a centralized scheduler. In this paper, a dynamic coordinated muting scheme is proposed using LTE Rel-11 framework for both Macro and HetNet scenarios. Next, the performance of CoMP using non-ideal backhaul is evaluated under various traffic models with distributed and centralized architectures separately. It is shown that dynamic coordinated muting scheme with NIB can achieve a cell edge gain of approximately 40% over a system without coordination for Macro only and ~10% over FeICIC based HetNet scenario. The simulation results also indicate that a centralized architecture is more sensitive to backhaul latency comparing with distributed approach. Finally, it is concluded that the current LTE distributed architecture is well suited to support coordinated scheduling with non-ideal backhaul.