Cooperative non-orthogonal multiple access for wireless communication networks by exploiting the EXIT chart analysis

Zeyad Elsaraf,Faheem Ahmad Khan,Abbas Ahmed,Qasim Zeeshan Ahmed

doi:10.1186/s13638-021-01961-z

Abstract

In the next generation of mobile communication networks, unprecedented challenges are required to be met, such as much higher data rates and spectrum efficiency, lower latency, and massive connectivity. Non-orthogonal multiple access (NOMA) has recently been proposed as a promising technology to achieve much superior spectral efficiency compared to conventional orthogonal multiple access techniques employed in present communication systems. A salient feature of NOMA is its use of successive interference cancellation (SIC) to decode users’ information when multiple users are allowed to transmit in same time/frequency/code domain. In this paper, we aim to exploit an aspect of SIC, namely the availability of other users’ data to realize a cooperative NOMA system. EXtrinsic information transfer (EXIT) charts are utilized to examine the performance of proposed system in terms of user fairness while employing IRregular convolutional codes (IRCC)s. The EXIT chart using IRCC evaluates the convergence analysis for the proposed system. Further, to evaluate the system performances in cooperative NOMA system, we have derived the expressions for the achievable rates which are obtained independently and utilized them in evaluating the experimental data for the proposed NOMA model.

Highlights

The extraordinary growth of wireless connectivity in recent years has led to a number of challenging needs for the development of next-generation wireless networks (NGWNs), which are indicated by the anticipation of nearly a thousand-fold increase in data traffic, much higher spectral efficiency, lower latency and massive connectivity [1,2,3,4]
Due to the higher power level as it is far away from the base station (BS), the Far user (FU) attains a better bit error rate (BER) compared to the Near user (NU) which is assigned very less power based on the distance between the FU from the BS
It is observed that at higher signal to noise ratio (SNR) values the FU data rate stagnates; as a result, the NU data rate exceeds it. This is because of the interuser interference (IUI) generated by the NU onto the FU, which directly increases with channel SNR

Summary

Introduction

The extraordinary growth of wireless connectivity in recent years has led to a number of challenging needs for the development of next-generation wireless networks (NGWNs), which are indicated by the anticipation of nearly a thousand-fold increase in data traffic, much higher spectral efficiency, lower latency and massive connectivity [1,2,3,4]. NOMA has gathered significant attraction in recent years and is considered as a promising multiple access technique for the NGWNs [5,6,7,8,9,10,11]. To fulfill the diverse requirements of the NGWNs, several new multiple access techniques have been designed during the last few decades [6, 14]. It is noted that NOMA can operate in combination with upcoming and existing communication technologies to fulfill the desired capacity for wireless networks, such as Massive Multiple Input Multiple Output (MIMO) [15], cooperative communications [16], cognitive radios [17], millimeter wave [18, 19], and visible light communication [20]. It has been observed that NOMA improves on the number of users supported as well as the performance of the system in various aspects

Objectives

Methods

Results

Conclusion