  Non-orthogonal multiple access (NOMA) is a promising multiple access
technology to improve the throughput and spectral efficiency of the users for
5G and beyond cellular networks. Similarly, coordinated multi-point
transmission and reception (CoMP) is an existing technology to improve the
coverage of cell-edge users. Hence, NOMA along with CoMP can potentially
enhance the throughput and coverage of the users. However, the order of
implementation of CoMP and NOMA can have a significant impact on the system
performance of Ultra-dense networks (UDNs). Motivated by this, we study the
performance of the CoMP and NOMA based UDN by proposing two kinds of user
grouping and pairing schemes that differ in the order in which CoMP and NOMA
are performed for a group of users. Detailed simulation results are presented
comparing the proposed schemes with the state-of-the-art systems with varying
user and base station densities. Through numerical results, we show that the
proposed schemes can be used to achieve a suitable coverage-throughout
trade-off in UDNs.
