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.

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 Reinforcement Learning-Based Joint User Pairing and Power Allocation in MIMO-NOMA Systems

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7094
Author(s):  
Jaehee Lee ◽  
Jaewoo So
Keyword(s):  
Reinforcement Learning ◽  
Computational Complexity ◽  
Power Allocation ◽  
Communication Systems ◽  
Multiple Input Multiple Output ◽  
Spectrum Efficiency ◽  
Q Learning ◽  
User Pairing ◽  
Input Multiple Output ◽  
Radio Resources

In this paper, we consider a multiple-input multiple-output (MIMO)—non-orthogonal multiple access (NOMA) system with reinforcement learning (RL). NOMA, which is a technique for increasing the spectrum efficiency, has been extensively studied in fifth-generation (5G) wireless communication systems. The application of MIMO to NOMA can result in an even higher spectral efficiency. Moreover, user pairing and power allocation problem are important techniques in NOMA. However, NOMA has a fundamental limitation of the high computational complexity due to rapidly changing radio channels. This limitation makes it difficult to utilize the characteristics of the channel and allocate radio resources efficiently. To reduce the computational complexity, we propose an RL-based joint user pairing and power allocation scheme. By applying Q-learning, we are able to perform user pairing and power allocation simultaneously, which reduces the computational complexity. The simulation results show that the proposed scheme achieves a sum rate similar to that achieved with the exhaustive search (ES).

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 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 Resource Allocation for Downlink Full-Duplex Cooperative NOMA-Based Cellular System with Imperfect SI Cancellation and Underlaying D2D Communications

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2768
Author(s):  
Asmaa Amer ◽  
Abdel-Mehsen Ahmad ◽  
Sahar Hoteit
Keyword(s):  
Resource Allocation ◽  
Channel Assignment ◽  
Interference Cancellation ◽  
Channel Allocation ◽  
Base Station ◽  
Cellular System ◽  
Full Duplex ◽  
D2d Communications ◽  
Power Budget

In this paper, the interplay between non-orthogonal multiple access (NOMA), device-to-device (D2D) communication, full-duplex (FD) technology, and cooperation networks is proposed, and a resource allocation problem is investigated. Specifically, a downlink FD cooperative NOMA-based cellular system with underlaying D2D communications is proposed, where, in each NOMA group, the strong user assists the weak user as an FD relay with imperfect self interference (SI) cancellation. In terms of reaping spectral efficiency benefits, the system sum rate is to be maximized by optimizing channel allocation. This optimization is based on quality of service (QoS) constraints of D2D pairs and cellular users (CUs), power budget of base station and strong user (cooperative phase), and successive interference cancellation (SIC) constraints. Since the maximization formulated problem is computationally challenging to be addressed, a two-sided stable many-to-one matching algorithm, based on Pareto improvement, performs sub-channel assignment. Extensive simulations are implemented to demonstrate the system performance indicated by different metrics.

scholarly journals Game-Theoretic Beamforming and Power Allocation in MIMO Cognitive Radio Systems with Transmitter Antenna Correlation

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Zhao ◽  
Hongsheng Wu ◽  
Hongbin Chen ◽  
Wen Wang
Keyword(s):  
Power Allocation ◽  
Communication Systems ◽  
Mimo Systems ◽  
Mimo System ◽  
Primary User ◽  
Noncooperative Game ◽  
Secondary Users ◽  
Game Theoretic ◽  
Antenna Correlation ◽  
Game Simulation

Multi-input multioutput (MIMO) technique provides a promising solution to enhance the performance of wireless communication systems. In this paper, we consider antenna correlation at the transmitter in practical cognitive MIMO systems. What is more, a game-theoretic framework is conducted to analyze the optimum beamforming and power allocation such that each user maximizes its own rate selfishly under the transmitting power constraint and the primary user (PU) interference constraint. The design of the cognitive MIMO system is formulated as a noncooperative game, where the secondary users (SUs) compete with each other over the resources made available by the PUs. Interestingly, as the correlation parameter grows, the utility degrades. Nash equilibrium is considered as the solution of this game. Simulation results show that the proposed algorithm can converge quickly and clearly outperforms the strategy without game.

scholarly journals Low-complexity beam-domain channel estimation and power allocation in hybrid architecture massive MIMO systems

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Xiao Chen ◽  
Zaichen Zhang ◽  
Liang Wu ◽  
Jian Dang
Keyword(s):  
Channel Estimation ◽  
Power Allocation ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Mimo Systems ◽  
Beam Steering ◽  
Estimation Method ◽  
Low Complexity ◽  
Estimation Accuracy ◽  
Hybrid Architecture

Abstract In this journal, we investigate the beam-domain channel estimation and power allocation in hybrid architecture massive multiple-input and multiple-output (MIMO) communication systems. First, we propose a low-complexity channel estimation method, which utilizes the beam steering vectors achieved from the direction-of-arrival (DOA) estimation and beam gains estimated by low-overhead pilots. Based on the estimated beam information, a purely analog precoding strategy is also designed. Then, the optimal power allocation among multiple beams is derived to maximize spectral efficiency. Finally, simulation results show that the proposed schemes can achieve high channel estimation accuracy and spectral efficiency.

scholarly journals User Pairing, Link Selection and Power Allocation for Cooperative NOMA Hybrid VLC/RF Systems

2020 ◽  
pp. 1-1
Author(s):  
Mohanad Obeed ◽  
Hayssam Dahrouj ◽  
Anas M. Salhab ◽  
Salam A. Zummo ◽  
Mohamed-Slim Alouini
Keyword(s):  
Power Allocation ◽  
Rf Systems ◽  
User Pairing
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