User Association Enabled Access Point Grouping in Het Nets

The multiple access technique used in cellular generations was OMA (Orthogonal Multiple Access), which uses different frequency for different users. They do not enjoy perfect connection in good or bad conditions. The introduction of NOMA (Non - Orthogonal Multiple Access) in 5G acts as a superior access method to OMA on various aspects, since it supports multiple users with the same frequency. Hence, spectral efficiency and throughput can be improved. In order to mitigate inter - cell interference, NOMA is implemented in ultra dense networks. The densification of network improves the co - operation among different access points for serving a single user, since the limited resources may degrade the network performance. The system efficiency can be improved to a great extent by grouping access points, since the user specific access framework provides access service. The densification of small cells and the non-orthogonality in resource sharing cause interference, user association is used to control the number of users assigned to each cell and it can control interference and to manage mobility.