Joint Transmission Coordinated Multipoint on Mobile Users in 5G Heterogeneous Network

To broaden user experience and support a wide range of bandwidth hungry devices cellular operators are adopting 5G network. However, the predominance of Inter-Cell Interference (ICI) in 5G stands as a hurdle for cell edge UEs. With increase in UE velocity, the effect of Doppler shift becomes more prominent, resulting in a significant drop in cell edge and mean data rates. A potential solution to improve the network service quality in the cell edge and reduce the impact of ICI for mobile users is to provide the UE with the best signal quality through coordination among multiple eNodeBs (eNB) located in different cell sites i.e., by virtually forming a massive antenna array with the coordinated eNB, a technique popularly known as Joint Transmission Coordinated Multipoint (JT CoMP). This paper investigates the performance of JT CoMP based heterogeneous network (HetNet) for UEs at different velocities while closed loop spatial multiplexing (CLSM) is active. With the inclusion of CLSM in JT CoMP, the obtained momentary channel state information can be utilized by coordinated eNBs for appropriate network gain enhancement. The simulation results demonstrate significant improvement in mean throughput and cell edge throughput for a CoMP based HetNet compared to a non-CoMP based HetNet with respect to UE velocity. The effectiveness of CLSM is found to degrade as UE velocity increases which is expected due to poor feedback capabilities of high velocity UEs. In contrast, simulation results show that the CLSM integrated inter-site based JT CoMP network provides improved reception for high velocity, while the intrasite-based CoMP network delivers better service at lower velocities.