The Performance Analysis of Downlink NOMA in LEO Satellite Communication System

Abstract

Non-orthogonal multiple access (NOMA) has the potential to provide higher throughput than conventional orthogonal multiple access (OMA), which has been considered as a key technology for 5G. NOMA in satellite communication system can provide anytime, anywhere access with improved spectral efficiency and system capacity because of its ubiquitous coverage. However, the characteristics of the satellite channels are different from that of the terrestrial network, i.e., huge time delay and Doppler shift. In this paper, different from the existing works, which mainly focus on the performance of NOMA in static terrestrial base stations and Geostationary orbit (GEO) scenarios, we investigate the performance analysis of downlink NOMA in dynamic low earth orbit (LEO) satellite communication system with Doppler shift considered. We combine NOMA and orthogonal frequency division multiplexing (OFDM) for better spectral efficiency. Our channel model includes both small scale model and large scale model. For simplify, we only consider two users in one spot beam. Besides, we express the performance analysis of downlink NOMA in LEO satellite communication system, like ergodic capacity, outage probability (OP) and mutual information. However, in traditional NOMA scheme, the proceeding error decision of the high power user will cause the deterioration of the subsequent detection performance. Therefore, a symmetrical coding (SC) scheme for different modulation mode is proposed for low power users to get better performance. Finally, simulation results validate the performance of the NOMA scheme is better than that of the OMA scheme. The proposed SC scheme can achieve a prominent increase performance contrasted to the traditional NOMA scheme. INDEX TERMS LEO satellite communication system, NOMA, ergodic capacity, outage probability, mutual information, symmetrical coding scheme. AIJUN LIU (Member, IEEE) received the B.S. degree in microwave communications and the M.S. and Ph.D. degrees in communications engineering and information systems from the College of Communications Engineering, Army Engineer

NOMA Receiver Design for Delay-Sensitive Systems

“…For simplicity, it is assumed that G = M and G = M = Z, for the first and second users, respectively. Tables II and III (28) where the BER Theo and BER Sim are the analytical and simulated BERs, respectively. The depicted results show that when {G, M } = 30, the truncation error is fairly insignificant for differentγ values and K = 6 dB.…”

“…The basic concept of power NOMA is that multiple users may share transmission resources simultaneously by assigning each user a particular power [25]. In the literature, successive interference cancelation (SIC) has been considered widely [9], [11], [13], [14], [16]- [18], [26]- [28] as the main detection scheme for NOMA signals. However, SIC detectors (SICDs) suffer from long processing times because the nth user has to sequentially detect, modulate, and subtract the signals of users 1, 2,. .…”

Enabling NOMA in Overlay Spectrum Sharing in Hybrid Satellite-Terrestrial Systems

“…Based on ( 20) and ( 21), we obtain the PDF of Z 1 . Unfortunately, it is difficult to obtain a closed-form expression from (31) as [35].…”

“…With the help ( 15) and ( 16), the PDF of Z 2 could be computed. To the best of authors' knowledge, (33) does not have a closed-form solution [35].…”

Joint User Pairing and Power Allocation for NOMA-Based GEO and LEO Satellite Network

“…Recently, NOMA is widely pursued for performance enhancement in satellite communication networks. Specifically, the effectiveness and superiority of the basic NOMA structure with one satellite and two ground users in GEO land mobile satellite networks [26] and LEO satellite networks [27] were validated by analyzing several key performance merits. Considering the cooperation with the terrestrial networks, ergodic capacity and outage performances in NOMA-based cognitive hybrid satellite-terrestrial networks were analyzed in [28]- [30].…”