scholarly journals Evaluation of Non-Orthogonal Techniques for Advance Wireless System

2019 ◽  
Vol 8 (2) ◽  
pp. 1849-1854

This article represents a comparative study of various types of multiple users’ access schemes for cellular radio system. One of the promising technique for the significant bandwidth efficiency enhancement in future wireless cellular system compared to the conventional multiple access technologies, especially orthogonal multiple access is Non-Orthogonal multiple access(NOMA). NOMA have grater spectral efficiency and more massive connectivity over orthogonal in fading environment. Third generation partnership projects have recently been proposed NOMA for 4G (3GPP-LTE-A). It is a Novel technique focusing the solution for 5G, advanced multimedia applications and Internet of things in terms of supporting massive heterogeneous data traffic. This review paper primarily focus on diverse NOMA techniques and provides a detailed outline of the Cutting edge in NOMA basic principles, NOMA power domain and its other variants.

Author(s):  
Aasheesh Shukla ◽  
◽  
Manish Kumar ◽  
Vinay Kumar Deolia ◽  
◽  
...  

Future communication networks may encounter various issues in order to facilitate heavy heterogeneous data traffic and large number of users, therefore more advanced multiple access (MA) schemes are being developed to meet the changing requirements. The research space on making more robust MA scheme is continuously increasing, so it becomes significant to analyze the various schemes to determine the appropriate MA scheme for 5G networks. Therefore, in this paper the comprehensive overview of the most popular and recent MA schemes is presented for 5G networks. This paper mainly classifies the MA techniques in orthogonal MA (OMA) and various types of non-OMA (NOMA) techniques. Specifically, we introduce RSMA (Rate splitting multiple access) and IDMA (interleave division multiple access). Further the close attention is paid to NOMA family, including code-domain NOMA (e.g., SCMA (sparse code multiple access)), power-domain NOMA. Above all, from this exploration, the opportunities and challenges could be notified in MA schemes and further the optimum MA technique can be point out among discussed MA schemes for 5G and beyond communication networks.


2020 ◽  
Vol 16 (4) ◽  
pp. 324-329
Author(s):  
Aasheesh Shukla

Future communication networks may encounter various issues in order to facilitate heavy heterogeneous data traffic and large number of users, therefore more advanced multiple access (MA) schemes is required to meet the changing requirements. Recently, a promising physical-layer MA technique has been suggested for multi-antenna broadcast channels, namely Rate Splitting Multiple Access (RSMA). This new scheme has the ability to partially decode the interference and partially treat the remaining interference as noise which makes it to cope with wide range of user deployments and network loads. On the other hand, interleave division multiple access (IDMA) has already been recognized as a potential code domain NOMA (non-orthogonal multiple access) scheme, suitable for 5G and beyond communication network. Hence, in this paper, a new approach of multiple access scheme is proposed to get the grip on new challenges in future communication (6G). The proposed framework consists the joint processing of RSMA and IDMA (code domain NOMA), in which the transmitter involves an IDMA as encoder and allows rate splitting to split the message in two parts i.e. common part and private part, before the actual transmission. The mathematical modeling of proposed system is elaborated in the paper and for simulation purpose the downlink communication scenario has been considered where users faced diverse channel conditions. The weighted sum rate (WSR) performance is evaluated for the proposed scheme which validate the quality of service (QoS) of the joint RS-IDMA system.


Author(s):  
Aiman Kassir ◽  
◽  
Rudzidatul Akmam Dziyauddin ◽  
Hazilah Mad Kaidi ◽  
Mohd Azri Mohd Izhar ◽  
...  

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Majidah H. Majeed ◽  
Riyadh Khlf Ahmed

AbstractSpectral Amplitude Coding-Optical Codes Division Multiple Access (SAC-OCDMA) is a future multiplexing technique that witnessed a dramatic attraction for eliminating the problems of the internet in optical network field such as multiple-user access and speed’s growth of the files or data traffic. In this research article, the performance of SAC-OCDMA system based on two encoding–decoding multidiagonal (MD) and Walsh Hadamard (WH) codes is enhanced utilizing three different schemes of dispersion compensating fiber (DCF): pre-, post- and symmetrical compensation. The system is simulated using Optisystem version 7.0 and Optigrating version 4.2. The performance of the proposed system is specified in terms of bit error rate (BER), Q-factor and eye diagram. It has been observed that the compensated system based on MD code is performs much better compared to the system based on WH code. On the other hand, the compensated SAC-OCDMA system with symmetrical DCF has the lowest values of BER and largest values of Q-factor, so it is considered the best simulated scheme contrasted with pre- and post-DCF.


2021 ◽  
Author(s):  
Navideh Ghafouri Jeshvaghani ◽  
Naser Movahhedinia ◽  
Mohammad Reza Khayyambashi

Abstract Non-orthogonal multiple access (NOMA) is one of the promising radio access techniques for resource allocation improvement in the 5th generation of cellular networks. Compared to orthogonal multiple access techniques (OMA), NOMA offers extra benefits, including greater spectrum efficiency which is provided through multiplexing users in the transmission power domain while using the same spectrum resources non-orthogonally. Even though NOMA uses Successive Interference Cancellation (SIC) to repeal the interference among users, user grouping has shown to have a substantial impact on its performance. This prformance improvement can appear in different parameters such as system capacity, rate, or the power consumption. In this paper, we propose a novel user grouping scheme for sum-rate maximization which increases the sum-rate up to 25 percent in comparison with two authenticated recent works. In addition to being matrix-based and having a polynomial time complexity, the proposed method is also able to cope with users experiencing different channel gains and powers in different sub-bands.


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