Performance of uplink WFRFT‐based hybrid carrier systems with non‐orthogonal multiple access. Issue 15 (23rd August 2018)

• Record Type: Journal Article
• Authors: Wang, Xiaolu; Labeau, Fabrice; Mei, Lin; Wang, Zhenduo; Sha, Xuejun
• Is Part Of: IET communications. Volume 12:Issue 15(2018)
• Page Start: 1891
• Page End: 1899
• Publication Date: 2018-08-23
• Subjects: Fourier transforms -- multi‐access systems -- interference suppression -- time‐frequency analysis -- decoding -- probability -- AWGN channels; uplink WFRFT‐based hybrid carrier system performance -- nonorthogonal multiple access -- weighted‐type fractional Fourier transform -- HC systems -- uplink non‐orthogonal multiple access scenario -- system capacity -- time‐frequency resources -- successive interference cancellation technique -- SIC technique -- signal decoding -- error decoding -- receiver -- inter‐user interference avoidance -- residual interference -- error propagation -- IUI power probability density function -- closed‐form expression -- PDF -- signal‐to‐interference‐plus‐noise ratio -- SINR -- additive white Gaussian noise channels -- near‐user bit error ratio expression -- optimal WFRFT order selection -- derivative test -- mathematical expression -- near‐user theoretical BER expression -- maximum sum spectral efficiency; Telecommunication systems -- Periodicals; Speech processing systems -- Periodicals; 621.38205
• DOI: 10.1049/iet-com.2018.5386
• Languages: English
• ISSNs: 1751-8628

Abstract

Abstract : In this paper, the performance of hybrid carrier (HC) systems based on weighted fractional Fourier transform (WFRFT) is investigated in an uplink non‐orthogonal multiple access (NOMA) scenario. NOMA is a promising technology to improve the system capacity, in which two users (far‐user and near‐user relative to a base station) are allocated to use the same time‐frequency resources, and the successive interference cancellation (SIC) technique is implemented to decode signals at the receiver. Considering the actual error decoding in the SIC process (i.e. imperfect SIC), NOMA cannot avoid the inter‐user interference (IUI) and residual interference (or error propagation). Therefore, firstly IUI and residual interference are analysed, and signal to interference plus noise ratio (SINR) of the far‐user is expressed mathematically considering the residual interference. Then, based on the analysis of IUI, considering different WFRFT orders, a near‐user BER expression over additive white Gaussian noise (AWGN) channels is derived. Furthermore, the optimal WFRFT order selection to minimise the interference influence in the uplink is formulated and solved efficiently. Simulation results have verified the mathematical expression of SINR, the near‐user theoretical BER expression, and the proposed optimal WFRFT order selection to obtain the maximum sum spectral efficiency.