Non‐orthogonal multiple access without channel state information for similar channel conditions

2019 ◽  
Vol 55 (8) ◽  
pp. 493-495 ◽  
Author(s):  
Wenlong Xia ◽  
Qingdang Meng ◽  
Qingchuan Tao ◽  
Ray T. Chen
Keyword(s):  
Channel State Information ◽  
Multiple Access ◽  
Channel State ◽  
State Information ◽  
Channel Conditions

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.

scholarly journals Performance Analysis of MEC Based on NOMA under Imperfect CSI with Eavesdropper

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xuehua Li ◽  
Yingjie Pei ◽  
Huan Jiang ◽  
Xinwei Yue ◽  
Yafei Wang ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Channel State Information ◽  
Multiple Access ◽  
System Throughput ◽  
Secrecy Outage Probability ◽  
Imperfect Csi ◽  
Channel State ◽  
State Information ◽  
Secrecy Outage ◽  
The Impact

Mobile edge computing (MEC) is becoming more and more popular because of improving computing power in virtual reality, augmented reality, unmanned driving, and other fields. This paper investigates a nonorthogonal multiple access- (NOMA-) based MEC system, which is under imperfect channel state information (ipCSI). In this system model, a pair of users offloads their tasks to the MEC server with the existence of an eavesdropper (Eve). To evaluate the impact of Eve on the performance of the NOMA-MEC system, the secrecy outage probability (SOP) expressions for two users with the conditions of imperfect CSI and perfect channel state information (pCSI) are derived. In addition, both throughput and energy efficiency are discussed in the delay-limited transmission mode. Simulation results reveal that (1) due to the influence of channel estimation errors, the secrecy outage behaviors of two users under ipCSI conditions are worse than those of users with pCSI; (2) the secrecy performance of NOMA-MEC is superior to orthogonal multiple access- (OMA-) aided MEC systems; and (3) the NOMA-MEC systems have the ability to attain better system throughput and energy efficiency compared with OMA-MEC.

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