scholarly journals Rayleigh Fading Multiple Access Channel Without Channel State Information

2004 ◽  
pp. 128-133 ◽  
Author(s):  
Ninoslav Marina
Keyword(s):  
Channel State Information ◽  
Multiple Access ◽  
Rayleigh Fading ◽  
Multiple Access Channel ◽  
Channel State ◽  
State Information ◽  
Access Channel

scholarly journals On the Performance of Energy Harvesting Non-Orthogonal Multiple Access Relaying System with Imperfect Channel State Information over Rayleigh Fading Channels

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3327 ◽  
Author(s):  
Tran Manh Hoang ◽  
Nguyen Le Van ◽  
Ba Cao Nguyen ◽  
Le The Dung
Keyword(s):  
Energy Harvesting ◽  
Fading Channels ◽  
Channel State Information ◽  
Multiple Access ◽  
Rayleigh Fading ◽  
Imperfect Channel State Information ◽  
Amplify And Forward ◽  
Channel State ◽  
State Information ◽  
Relaying System

In this paper, we propose a non-orthogonal multiple access (NOMA) relaying system, where a source node communicates simultaneously with multiple users via the assistance of the best amplify-and-forward (AF) relay. The best relay is selected among N relays which are capable of harvesting the energy from radio frequency (RF) signals. We analyze the performance of the proposed NOMA relaying system in the conditions of imperfect channel state information (CSI) and Rayleigh fading by deriving the exact expressions of the outage probability (OP) and the approximate expression of the ergodic capacities of each user and the whole system. We also determine the optimal energy harvesting duration which minimizes the OP. Numerical results show that, for the same parameter settings, the performance of the proposed NOMA relaying system, especially the ergodic capacity of the whole system, outperforms that of the orthogonal-multiple-access (OMA) relaying system. Monte-Carlo simulations are used to validate the correctness of the analytical results.

scholarly journals A Joint Optimization Scheme of Resource Allocation in Downlink NOMA with Statistical Channel State Information

2020 ◽  
Author(s):  
Lei Xu ◽  
Jing Yi Yao ◽  
Jing Cai ◽  
Yu Hong Fang ◽  
Hui Xiao Li
Keyword(s):  
Power Allocation ◽  
Channel State Information ◽  
Communication Systems ◽  
Multiple Access ◽  
Joint Optimization ◽  
System Throughput ◽  
Optimization Scheme ◽  
Channel State ◽  
State Information ◽  
User Grouping

Abstract In a real communication scenario, it is very difficult to obtain the real-time Channel State Information(CSI) accurately, so the communication systems with statistical CSI have been researched. In order to maximize the throughput of the downlink Non-Orthogonal Multiple Access (NOMA) system with statistical CSI, the formula of system throughput is derived at first. Then, according to the combinatorial characteristics of the original optimization problem, it is divided into two subproblems, that is user grouping and power allocation. At last, a joint optimization scheme is proposed. In which, Genetic algorithm is introduced to solve the subproblem of power allocation, and Hungarian algorithm is introduced to solve the subproblem of user grouping. By comparing the ergodic date rate of NOMA users with statistical CSI and perfect CSI, the effectiveness of the statistical CSI sorting is verified. Compared with the Orthogonal Multiple Access (OMA) scheme, the NOMA scheme with the fixed user grouping scheme and the random user grouping scheme, the proposed scheme can effectively improve the system throughput.

scholarly journals Channel and Bit Adaptive Power Control Strategy for Uplink NOMA VLC Systems

2019 ◽  
Vol 9 (2) ◽  
pp. 220 ◽  
Author(s):  
Zhen-Yu Wang ◽  
Hong-Yi Yu ◽  
Da-Ming Wang
Keyword(s):  
Power Control ◽  
Power Allocation ◽  
Channel State Information ◽  
Control Strategy ◽  
Multiple Access ◽  
Visible Light Communication ◽  
Allocation Scheme ◽  
Channel State ◽  
State Information ◽  
Adaptive Power

Non-orthogonal multiple access (NOMA) can be an effective solution to the limited bandwidth of light emitting diodes for visible light communication (VLC) systems to support multiuser communication. The current available works for NOMA VLC systems mainly concentrate on downlinks and the existing power allocation algorithms mainly focus on the channel state information and ignore the influence of transmitted signals. In this paper, we propose a channel and bit adaptive power control strategy for uplink NOMA VLC systems by jointly considering the channel state information and the transmission bit rate. Under this adaptive power control strategy, it is proved that the received signal at the photodiode (PD) receiver constitutes a sizeable pulse amplitude modulation constellation and low-complexity maximum likelihood detection is admitted. The simulation results indicate that our proposed adaptive power control strategy outperforms the gain ratio power allocation scheme, fixed power allocation scheme, and time division multiple access scheme.

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