IM-Based Multiple Access Techniques in 5g Networks: A Novel Scheme and Performance Analysis

Abstract

In the next generations of communication systems, resources' scarcity devolves to a more critical point as a consequence of the expected massive number of users to be served. Furthermore, the users' contradicting requirements on quality of service forces the network to behave in a dynamic way in terms of the multiple access orchestration and resource assignment between users. Hence, the linear relation between the number of served users and the required (orthogonal or semi-orthogonal) resources is no longer sufficient as in the orthogonal multiple access (OMA) schemes. Non-orthogonal multiple access (NOMA) schemes and index modulation (IM) techniques emerge as candidates to satisfy the ever-increasing spectral efficiency and connectivity demands. In this thesis, a comprehensive literature review is conducted on the IM-based multiple access techniques, and a novel IM-based NOMA downlink scheme, termed as IM-NOMA, is proposed, where the Base Station (BS) selects a channel or more to serve each user based on the IM concept and the corresponding power level is allocated based on the NOMA concept. At the users' ends, two detection techniques, namely maximum likelihood (ML) and successive interference cancellation (SIC), are considered and their error rate, outage probability and computational complexity are analyzed. Furthermore, a low computationally complex detection technique is designed for the proposed IM-NOMA scheme. Multiple numerical simulations are conducted to verify the efficiency of the proposed scheme and to validate the analytical findings. Simulation results show the accuracy of the analytical formulas and that the proposed IM-NOMA can outperform the conventional NOMA scheme and the related state-of-the art schemes in terms of error performance