Forward-Reverse Orthogonal Matching Pursuit-Union-Subspace Pursuit-Based Multiuser Detector for Uplink Grant-Free NOMA Networks

Olutayo Oyeyemi Oyerinde

doi:10.3390/electronics11010125

Olutayo Oyeyemi Oyerinde

Open Access

https://doi.org/10.3390/electronics11010125

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Journal: Electronics	Publication Date: Dec 31, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: University of the Witwatersrand

Abstract

Multiuser Detection (MUD) is quite challenging in uplink grant-free non-orthogonal multiple access wireless communication networks in which users sporadically transmit data. The reason for this is that the base station (BS) must perform detection of both multiuser activity and user signals concurrently, because knowledge of user activity status is not available at the BS. In this paper, a new multiuser detector, named the Forward-Reverse Orthogonal Matching Pursuit–Union–Subspace pursuit (FROMPUS)-based MUD, is proposed. The detector takes advantage of the concept of an initial support set. This serves as initial knowledge that is then employed in the reconstruction of active users’ signals. In addition, the detector uses the “serial-include” technique of incorporating a likely support set element candidates and a reliability testing procedure in which the most prominent elements of the support set are selected. To assess the performance of the proposed detector, computer simulations are performed. The results obtained for various parameter settings show that the FROMPUS performs better than any of the other five detectors considered in this paper. However, this excellent performance comes with a slightly higher computational complexity cost. Nonetheless, the cost is inconsequential, since the detector operates at the BS where complexity is of low priority in comparison to performance.

Highlights

These multiuser detection (MUD) are the OMPbased MUD and Comp Efficient OMP-based MUD presented in [22], the modified subspace pursuit-based MUD [23], the modified orthogonal matching pursuit-based MUD [24], and the simultaneous orthogonal matching pursuit (SOMP)-based MUD developed for signal recovery in an measurement vector (MMV) model [11]
An oracle least square (Oracle LS) algorithm-based MUD that possesses both accurate knowledge of the positions of the elements in X that are non-zero as well as the correct support set of the users is employed for benchmarking the performance of the proposed Forward-Reverse Orthogonal Matching Pursuit– Union–Subspace pursuit (FROMPUS)-based MUD and the other MUDs
The total number of users U in the GF-non-orthogonal multiple access (NOMA) network is initially set at 50 and changed for subsequent simulations in order to obtain the results presented

Summary

Introduction

The advent of the fifth and beyond fifth generation (5G) of wireless communication networks brings along with it the massive connectivity of users and devices, short message packets, low latency, sporadic communication, and low power, just to mention a few aspects. Among the works in this category is that presented in [15], in which a compressive sensing algorithm without knowledge of the sparsity level, as proposed in [14], is extended for the estimation of multiuser activity and the detection of users’ signals in uplink GF-NOMA systems. In [21], the authors propose a combination of a channel estimation scheme and a multiuser detection (MUD) technique for scenarios in which users are either active or inactive in a frame in uplink GF-NOMA communication networks. The performance of the proposed FROMPUS-based MUD algorithm is presented and compared with other considered MUDs in the context of uplink GF-NOMA wireless communication. 4 ofThe performance of the proposed FROMPUS-based MUD algorithm is presented and compared with other considered MUDs in the context of uplink GF-NOMA wireless communication networks.

The Proposed Detector for Uplink GF-NOMA Networks

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Computer Simulation Results

The least

Conclusions and Future Works