Analysis of CoMP-Assisted Cooperative NOMA for Enhanced Coverage

Abstract

The demand for high data rates and enhanced capacity has increased in a few years and Non-orthogonal multiple access (NOMA) plays a vital role in achieving this. Millimeter-Wave (mmWave) frequency band (30 GHz - 300 GHz) is taken into account to tackle spectrum scarcity. Millimeter-wave technology merged with NOMA to reduce the outage probability and to achieve higher sum rates. In this thesis, the concept of coordinated multipoint transmission of Base Stations and cooperative transmission is used in multi-cell mm-wave based NOMA network to achieve good results for the NOMA far user or cell edge user in the downlink transmission. Multiple base stations do the first joint transmission to NOMA users. At the near NOMA user, successive interference cancellation (SIC) is used to detect the signal while the NOMA far user decodes its signal directly. And then the concept of cooperative NOMA is used in which the near NOMA user forwards the decoded message to the NOMA far user. Work is done for considering both line-of-sight and non-line-of-sight links. Subsequently, the sum rates, outage probability, and energy efficiency are found to show the superiority of the techniques used to enhance the overall performance of the cell-edge users. In a multi-cell network, the combination of coordinated multipoint (CoMP) transmissions and non-orthogonal multiple access (NOMA) is an effective solution to mitigate inter-cell interference and enhance the data rates of the cell edge users. While the existing studies heavily focus on maximizing the data rate of the cell edge users or the sum rate of the network, energy efficiency has not been thoroughly investigated. In particular, when it comes to amalgamating CoMP with cooperative NOMA (C-NOMA), various system configurations should be considered, which impact both data rate and energy efficiency. Therefore, in this research work, we provide an optimization framework of energy efficiency specifically for the edge user using a Markov decision process (MDP) where the underlying system leverages the benefits of both CoMP and C-NOMA. The simulation results demonstrate the effectiveness of the proposed approach for the joint optimization of data rate and energy efficiency.