Study of downlink PD-NOMA for enhanced spectrum and energy efficient system with interference management through NOMA clustering

Abstract

With the advancement of wireless communication systems, the demand for higher data rates is increasing exponentially. Non-Orthogonal Multiple Access (NOMA) is expected to play an important role in 5G networks. In contrast to conventional Orthogonal multiple access schemes, NOMA allows different users to efficiently share the same resources (i.e., time, frequency, and code) at different power levels so that the user with lower channel gain is served with a higher power and vice versa. As a result, it increases the system performance compared to traditional orthogonal multiple access techniques. In this thesis work, we have analyzed the performance of different users Power Domain NOMA (PD-NOMA) system in a Downlink scenario in terms of Sum Capacity, Spectral Efficiency, Energy Efficiency, and total Interference. We have analyzed the system performance with and without employing SVD precoding technique, under different power allocation schemes (Fixed Power Allocation and Dynamic Power Allocation) and different modulation techniques. As we increase the number of users in the system, we observe that NOMA technique suffers from increased interference among the users sharing the same resources. NOMA Clustering technique can resolve the problem by grouping users into clusters. As a result, interference among users in a cluster decreases and system performance improves. Here we have discussed 3 types of clustering. We have analyzed the performance of NOMA Clustering system employing SVD precoding technique, under different power allocation schemes (Fixed Power Allocation and Dynamic Power Allocation) and different modulation techniques and compare the performance of PD-NOMA Clustering system with the performance of PD-NOMA system in a downlink scenario. We have performed these experiments using a transceiver board named WARP V3 in 2.4GHz band and MATLAB software.