Abstract
Non-orthogonal multiple access (NOMA) is a technique which allows multiple users to share the same radio access resources. However, there exist interferences among these users in the NOMA system. These interferences need to be taken into account in the signal detection and error performance analysis. In the downlink NOMA system, the far user detects its signal by treating the near user's signal as interference, while the near user employs successive interference cancellation (SIC) to detect its signal. Based on the conventional signal detection, it is not straightforward to derive the error performance for both the far user and near user. By analyzing the constellation relationships between the far user's signal and superposition coded (SC) signal, and the near user's signal and SC signal, in this article, a simple threshold based detection algorithm is proposed to detect both the far user's signal and near user's signal. Furthermore, by aid of the constellation relationships, in this article, simple expressions of the average symbol error probability (ASEP) with squared M -ary quadrature amplitude modulation for both the far user and near user are easily derived in Rayleigh fading channels. Simulation results validate the derived theoretical ASEP results.
Highlights
N OWADAYS there is an ever-growing demand for high data transmission rates and reliability in wireless communication systems
“1 × Nr Mf -MnQAM User u Csimula, simula or theory”, 1 × Nr denotes that the BS is equipped with one transmit antenna, and User u is equipped with Nr receiver antennas; Mf -MnQAM denotes that the symbols to be transmitted to User f and User n are Mf QAM and MnQAM, respectively; “Csimula, simula or theory” denote simulation based on conventional detection, simulation based on proposed threshold based detection and theoretical results based on (43), respectively
It is observed that the theoretical results match very well with the simulation results for other SNR ranges for two DL-Non-orthogonal multiple access (NOMA) systems with Nr = 1 and Nr = 2
Summary
N OWADAYS there is an ever-growing demand for high data transmission rates and reliability in wireless communication systems. Nonorthogonal multiple access (NOMA) has been considered as a promising technique to improve data transmission rate in 5G wireless communication system [1,2]. In [4] and [7], the error performance of the DL-NOMA system is analyzed based on the conventional signal detection. The average symbol error probabilities (ASEPs) for both the far user and near user are derived in Rayleigh fading channels considering imperfect SIC. By analyzing the constellations of the individual user’s signal and the SC signal, we firstly propose a threshold based simple signal detection algorithm for both the far user and near user. The main contributions of this paper are summarized as: 1) A threshold based simple signal detection for both the far user and near user is proposed.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
