Mutual Successive Interference Cancellation Strategies in NOMA for Enhancing the Spectral Efficiency of CoMP Systems

Abstract

The densification of mobile networks should enable the fifth generation (5G) mobile networks to cope with the ever increasing demand for higher rate traffic, reduced latency, and improved reliability. The large scale deployment of small cells and distributed antenna systems in heterogeneous environments will require more elaborate interference mitigating techniques to increase spectral efficiency and to help unlock the expected performance leaps from the new network topologies. Coordinated multi-point (CoMP) is the most advanced framework for interference management enabling the cooperation between base stations to mitigate inter-cell interference and boost cell-edge user performance. In this paper, we study the combination of CoMP with mutual SIC, an interference cancellation technique based on power-domain non-orthogonal multiple access (NOMA) that enables multiplexed users to simultaneously cancel their corresponding interfering signals. A highly efficient intercell interference cancellation scheme is then devised, that can encompass several deployment configurations and coordination techniques. The obtained results prove the superiority of this approach compared to conventional NOMA-CoMP systems.

Analysis of Drone Placement Strategies for Complete Interference Cancellation in Two-Cell NOMA CoMP Systems

“…Moreover, to take advantage of the cooperation between the cells and to properly manage inter-cell interference, cell-center users from cell 1 and 2 should be considered as well. The interference management can be done through NOMA pairing of users from both cells, as was done in [22]. For this purpose, we focus our study on a three-user NOMA cluster formed by a triplet of users selected from regions 1, 2 and 3 of the two cells, as shown in Fig.…”

“…It is assumed that the information to be transmitted for each user is made available at the level of the BS and MBS through the backhaul link, enabling DPS and JT serving in the system. JTmode is used in the remainder of the study, given its superior performance to DPS, as shown in [22]. FIGURE 1: Illustration of the two-cell JT system with the functional base station a 1 , the saturated BS in cell 2, the UAV working as MBS a 2 , and the three colored user regions.…”

“…The objective of this study is to serve the three users such that the resulting channel gains from the UAV position allow the application of TMSIC on their sub-band. By doing so, system throughput and fairness would be optimized, as shown in [22]. Note that other users in the system are assumed to be served on different sub-bands, without causing interference on the considered user triplet.…”

“…For more details, the reader is referred to [22]. The achieved rate by each user k, when JT-CoMP is used to apply TMSIC between the user triplet, is given by:…”

“…In a previous work, we studied the combination of NOMA with CoMP for a two-cell system [22]. A full JT system over NOMA clusters of two and three users was studied showing significant advantages over partial JT (where JT is only used for cell-edge users and DPS is used for cellcenter users).…”