scholarly journals Joint user pairing and power allocation scheme based on transmission mode switching between NOMA based maximum ratio transmission and MMSE beamforming in downlink MISO systems

2021 ◽  
Author(s):  
Zhixin Zhao ◽  
Dong Wang ◽  
Hongwei Zhang ◽  
Haitao Sang
Keyword(s):  
Power Allocation ◽  
Mode Switching ◽  
Achievable Rate ◽  
Rate Performance ◽  
User Pairing ◽  
Rate Region ◽  
Transmission Modes ◽  
Sum Rate ◽  
Ratio Transmission ◽  
Maximum Ratio Transmission

Abstract IThis paper investigates the design of the joint user pairing and power allocation scheme with transmission mode switching (TMS) in downlink multiple-input-single-output (MISO) systems. Firstly, the closed-form expressions of the boundary of achievable rate region of two candidate transmission modes, i.e., non-orthogonal multiple access based maximum ratio transmission (NOMA-MRT) and minimum mean square error beamforming (MMSE-BF), are obtained. By obtaining the outer boundary of the union of the achievable rate regions of the two transmission modes, an adaptive switching method is developed to achieve a larger rate region. Secondly, based on the idea that the solution to the problem of weighted sum rate (WSR) optimization must be on the boundary of the achievable rate region, the optimal solutions to the problem of WSR optimization for NOMA-MRT and MMSE-BF are obtained for the two-user case, respectively. Subsequently, by exploiting the optimal solutions aforementioned for two transmission modes and the high efficiency of TMS, a suboptimal User pairing and Power Allocation algorithm (JUPA) is proposed to further improve sum-rate performance for the multi-user case. Compared with the Exhaustive Search based user Pairing and Power Allocation algorithm (ES-PPA), the proposed JUPA can enjoy a much lower computational complexity and only suffer a slight sum-rate performance loss, whereas outperforms other traditional schemes. Finally, numerical results are provided to validate the analyses and the proposed algorithms.

scholarly journals Joint User Pairing and Power Allocation Scheme Based on Transmission Mode Switching between NOMA-Based Maximum Ratio Transmission and MMSE Beamforming in Downlink MISO Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Zhixin Zhao ◽  
Dong Wang ◽  
Hongwei Zhang ◽  
Haitao Sang
Keyword(s):  
Power Allocation ◽  
Mode Switching ◽  
Achievable Rate ◽  
Rate Performance ◽  
User Pairing ◽  
Rate Region ◽  
Transmission Modes ◽  
Sum Rate ◽  
Ratio Transmission ◽  
Maximum Ratio Transmission

This paper investigates the design of the joint user pairing and power allocation scheme with transmission mode switching (TMS) in downlink multiple-input-single-output (MISO) systems. Firstly, the closed-form expressions of the boundary of achievable rate region of two candidate transmission modes, i.e., non-orthogonal multiple access based maximum ratio transmission (NOMA-MRT) and minimum mean square error beamforming (MMSE-BF), are obtained. By obtaining the outer boundary of the union of the achievable rate regions of the two transmission modes, an adaptive switching method is developed to achieve a larger rate region. Secondly, based on the idea that the solution to the problem of weighted sum rate (WSR) optimization must be on the boundary of the achievable rate region, the optimal solutions to the problem of WSR optimization for NOMA-MRT and MMSE-BF are obtained for the two-user case, respectively. Subsequently, by exploiting the aforementioned optimal solutions for two transmission modes and the high efficiency of TMS, a suboptimal user pairing and power allocation algorithm (JUPA) is proposed to further improve the sum rate performance for the multiuser case. Compared with the exhaustive search-based user pairing and power allocation algorithm (ES-PPA), the proposed JUPA can enjoy a much lower computational complexity and only suffers a slight sum rate performance loss, and it outperforms other traditional schemes. Finally, numerical results are provided to validate the analyses and the proposed algorithms.

scholarly journals Adaptive transmission mode switching in downlink MISO-NOMA systems: sum rate maximization and the achievable rate region

2020 ◽  
Author(s):  
Zhixin Zhao ◽  
Dong Wang ◽  
Hongwei Zhang ◽  
Haitao Sang
Keyword(s):  
Power Allocation ◽  
Adaptive Transmission ◽  
Transmission Mode ◽  
Mode Switching ◽  
Achievable Rate ◽  
Rate Performance ◽  
Optimal Solutions ◽  
User Pairing ◽  
Rate Region ◽  
Sum Rate

Abstract In this paper, the design of adaptive transmission mode switching (TMS) to maximize the sum rate for the downlink multiple-input-single-output based non-orthogonal multiple access (MISO-NOMA) systems is investigated. Firstly, the colsed-form expressions of the boundary of achievable rate region of two candidate transmission mode, i.e., NOMA-based maximum ratio transmission (NOMA-MRT) and minimum mean square error beamforming (MMSE-BF), are obtained. By obtaining the outer boundary of the union of the achievable rate regions of the two transmission mode, an adaptive switching method is developed to achieve a larger rate region. Secondly, based on the idea that the solution to the problem of weighted sum rate (WSR) optimization must be on the boundary of achievable rate region, the optimal solutions to the problem of WSR optimization for NOMA-MRT and MMSE-BF are obtained, respectively. Subsequently, by exploiting the optimal solutions aforementioned for two transmission modes and the high efficiency of TMS, a low-complexity Joint User pairing and Power Allocation algorithm (JUPA) is proposed to further improve sum-rate performance for the multi-user case. Compared with the Exhaustive Search based user Pairing and Power Allocation algorithm (ES-PPA), the proposed JUPA can enjoy a much lower computation complexity and only suffer a slight sum-rate performance loss, whereas outperforms other traditional schemes. Finally, numerical results are provided to validate the analyses and the proposed algorithms.

scholarly journals Performance Analysis of Linear Precoding in Downlink Based on Polynomial Expansion on Massive MIMO Systems

2021 ◽  
Vol 2062 (1) ◽  
pp. 012006
Author(s):  
Sammaiah Thurpati ◽  
Mahesh Mudavath ◽  
P. Muthuchidambaranathan
Keyword(s):  
Performance Analysis ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Polynomial Expansion ◽  
Achievable Rate ◽  
Linear Precoding ◽  
Zero Forcing ◽  
Sum Rate ◽  
Ratio Transmission ◽  
Maximum Ratio Transmission

Abstract The performance of linear precoding schemes in downlink Massive MIMO systems is dealt with in this paper. Linear precoding schemes are incorporated with zero-forcing (ZF) and maximum ratio transmission (MRT), truncated polynomial expansion (TPE), regularized zero force (RZF) in Downlink massive MIMO systems. Massive MIMO downlink output is evaluated with linear precoding included. This paper expresses the performance of achievable sum-rate linear precoding with variable signal-to-noise (SNR) ratio and achievable sum rate and several transmitter-receiver antennas, such as imperfect CSI, less complex processing, and inter-user interference. The transmitter has complete state information on the channel. The information narrates how a signal propagates to the receiver from the transmitter and reflects, for example, the cumulative effect of distance scattering, fading, and power decay. They show that the performance analysis of two linear precoding techniques, i.e., Maximum Ratio Transmission (MRT) and Zero Forcing (ZF) for downlink mMIMO output network over a perfect chain. The results show the improved ZF precoding achievable sum rate compared to the MRT precoding schemes and compared the average achievable rate RZF and TPE.

scholarly journals Novel Resource Allocation Techniques for Downlink Non-Orthogonal Multiple Access Systems

2020 ◽  
Vol 10 (17) ◽  
pp. 5892 ◽  
Author(s):  
Zuhura J. Ali ◽  
Nor K. Noordin ◽  
Aduwati Sali ◽  
Fazirulhisyam Hashim ◽  
Mohammed Balfaqih
Keyword(s):  
Resource Allocation ◽  
Energy Efficiency ◽  
Power Allocation ◽  
Multiple Access ◽  
High Capacity ◽  
Kkt Conditions ◽  
Optimal Power Allocation ◽  
User Pairing ◽  
Optimal Power ◽  
Sum Rate

Non-orthogonal multiple access (NOMA) plays an important role in achieving high capacity for fifth-generation (5G) networks. Efficient resource allocation is vital for NOMA system performance to maximize the sum rate and energy efficiency. In this context, this paper proposes optimal solutions for user pairing and power allocation to maximize the system sum rate and energy efficiency performance. We identify the power allocation problem as a nonconvex constrained problem for energy efficiency maximization. The closed-form solutions are derived using Karush–Kuhn–Tucker (KKT) conditions for maximizing the system sum rate and the Dinkelbach (DKL) algorithm for maximizing system energy efficiency. Moreover, the Hungarian (HNG) algorithm is utilized for pairing two users with different channel condition circumstances. The results show that with 20 users, the sum rate of the proposed NOMA with optimal power allocation using KKT conditions and HNG (NOMA-PKKT-HNG) is 6.7% higher than that of NOMA with difference of convex programming (NOMA-DC). The energy efficiency with optimal power allocation using DKL and HNG (NOMA-PDKL-HNG) is 66% higher than when using NOMA-DC.

scholarly journals Joint User Pairing, Channel Assignment and Power Allocation in NOMA based CR Systems

2019 ◽  
Vol 9 (20) ◽  
pp. 4282 ◽  
Author(s):  
Zain Ali ◽  
Yanyi Rao ◽  
Wali Ullah Khan ◽  
Guftaar Ahmad Sardar Sidhu
Keyword(s):  
Power Allocation ◽  
Channel Assignment ◽  
Communication Systems ◽  
Channel Allocation ◽  
Optimization Technique ◽  
Achievable Rate ◽  
Power Budget ◽  
Secondary Users ◽  
User Pairing ◽  
Cr System

The fifth generation (5G) wireless communication systems promise to provide massive connectivity over the limited available spectrum. Various new transmission paradigms such as non-orthogonal multiple access (NOMA) and cognitive radio (CR) have emerged as potential 5G enabling technologies. These techniques offer high spectral efficiency by allowing multiple users to communicate on the same frequency channel, simultaneously. A combination of both techniques may further enhance the performance of the system. This work aims to maximize the achievable rate of a multi-user multi-channel NOMA based CR system. We propose an efficient user pairing, channel assignment and power optimization technique for the secondary users while the performance of primary users is guaranteed through interference temperature limits. The results show that, at small values of the power budget or high interference threshold, optimizing channel allocation and user pairing proves to be more beneficial than optimal power allocation to the user pairs. The proposed joint optimization technique provides promising results for all values of the power budget, interference threshold and rate requirement of the communicating users.

The Performance Analysis of Two Conventional Linear Pre-Coding Schemes in Massive MIMO System with Imperfect CSIT

2014 ◽  
Vol 668-669 ◽  
pp. 1386-1390
Author(s):  
Ren Kai Yu ◽  
Jun Xuan Wang ◽  
You Ming Sun ◽  
Yang Liu
Keyword(s):  
Performance Analysis ◽  
Massive Mimo ◽  
Mimo System ◽  
Zero Forcing ◽  
Low Snr ◽  
Coding Schemes ◽  
Sum Rate ◽  
Ratio Transmission ◽  
Maximum Ratio Transmission

For this paper, we analyze the achievable sum rate of zero-forcing (ZF) pre-coding and Maximum Ratio Transmission (MRT) pre-coding with Matrix Normalization in massive MIMO system with Imperfect CSIT. We compare the performances of these two pre-codings and find that ZF pre-coding outperforming MRT pre-coding in the high SNR region while MRT pre-coding outperforming ZF pre-coding in the low SNR region. Then we derive the threshold of the pre-coding selection and provide the procedure of pre-coding schemes selection.

scholarly journals PSO-Based UAV Deployment and Dynamic Power Allocation for UAV-Enabled Uplink NOMA Network

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Sharief Abdel-Razeq ◽  
Hazim Shakhatreh ◽  
Ali Alenezi ◽  
Ahmad Sawalmeh ◽  
Muhammad Anan ◽  
...  
Keyword(s):  
Power Allocation ◽  
Pso Algorithm ◽  
Base Stations ◽  
Allocation Strategy ◽  
Dynamic Power ◽  
User Pairing ◽  
Data Rates ◽  
Fixed Power ◽  
Sum Rate ◽  
The One

Recently, unmanned aerial vehicles (UAVs) have been used as flying base stations (BSs) to take advantage of line-of-sight (LOS) connectivity and efficiently enable fifth-generation (5G) and cellular network coverage and data rates. On the other hand, nonorthogonal multiple access (NOMA) is a promising technique to help achieve unprecedented requirements by simultaneously allowing multiple users to send data over the same resource block. In this paper, we study a UAV-enabled uplink NOMA network, where the UAV collects data from ground users while flying at a certain altitude. Unlike all existing work on this topic, this study consists of two stages. In the first stage, we use the well-known Particle Swarm Optimization (PSO) algorithm, which is a metaheuristic algorithm, to deploy the UAV in 3D space, so that the users’ sum pathlosses are minimized. In the second stage, we investigate the user pairing problem and propose a dynamic power allocation technique for determining the user’s power allocation coefficients, as well as a closed-form equation for the ergodic sum-rate. Results show our PSO-based algorithm prevailing over the Genetic Algorithm (GA) and random deployment methods. The proposed dynamic power allocation strategy maximizes the network’s ergodic sum-rate and outperforms the fixed power allocation strategy. Additionally, the results reveal that the best pairing scheme is the one that keeps uniform channel gain difference in the same pair.

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