A spectral efficient spatially modulated non-orthogonal multiple access for 5G

Abstract

Non-orthogonal multiple access (NOMA) is a promising candidate for 5G networks. NOMA achieves superior spectral efficiency than conventional orthogonal multiple access (OMA), as in NOMA multiple users can use the same time and frequency resources. Multiple-Input-multiple-output is a promising technique that can enhance system performance. In this paper we present a multiple antenna based NOMA, known as spatially modulated NOMA. In proposed scheme different users are multiplexed in power domain while cell edge users are multiplexed in spatial domain. The information to cell edge users are conveyed using antenna indices thereby reduces number of decoding steps at NOMA users, cell edge interference reduces as no power is allocated to cell edge users and hence is more energy efficient as compare to conventional NOMA. Simulation results shows that proposed scheme achieves superior spectral efficiency as compare to conventional NOMA.

Non-orthogonal multiple access in downlink coordinated multipoint transmissions

“…Considering SM based space shift keying (SSK), it activates an antenna to transmit frequency for NOMA users while another antenna is utilized as an index modulation [15,16]. It is important to be noted that generalized SSK (GSSK) is required by putting more BS antennas while SM users require more capacity or K number of users are considered [17,19].…”

“…Regarding the issues, spatial modulation (SM) technique is considered may handle multiple CCUs and/or multiple CEUs efficiently [13][14][15][16][17]. Considering conventional CoMP can handle M number of CCUs and one CEU within M number of CoMP BSs, SM is utilized to handle the other users that cannot be served by using conventional CoMP [16,17]. In this paper, conventional CoMP is used because power allocated for CEU can be optimized while the number of CoMP BSs is increased.…”

On Maximizing Energy and Spectral Efficiencies Using Small Cells in 5G and Beyond Networks

“…Achieving high network SE is considered as one of the major traditional approaches to designing mobile networks. Accordingly, extensive studies, e.g., [8][9][10][11][12], have already addressed the SE issue of mobile networks. However, recently, environmental protection and energy-saving have also become potential issues raised by global communities, resulting in asking researchers for shifting focus towards energy-efficient network design approaches [13].…”

Performance Analysis of SSK-NOMA

“…To increase number of the served users in a orthogonal block (i.e., time, frequency, code), SSK combination with the NOMA is considered in [32] where the cell-edge user is assigned into spatial domain and two users are multiplexed with NOMA. Then, the authors in [33] have extended [32] for more than three users where cell-edge users are allocated to spatial domain (i.e., antenna index) and the intra-cell users are served by conventional NOMA and it is called as Generalized SSK-NOMA (GSSSK-NOMA). In [33], the complexity analysis for GSSK-NOMA and BER simulations for cell-edge user is given.…”

“…In [33], the complexity analysis for GSSK-NOMA and BER simulations for cell-edge user is given. However, ML detections for cell-edge users provided in [32], [33] have unrealistic assumptions such as superimposed NOMA signal is perfectly known at the cell-edge users. Hence, the provided detectors and the analysis turn out to be well-known conventional GSSK networks rather than GSSK-NOMA networks.…”