Resource Allocation and Power Control Based on Noncooperative Game for D2D Communications Underlaying Cellular Networks

Wireless Personal Communications - The development of computer technology paves the way for transferring conventional monitoring system into digital monitoring. Considering this idea, the concept...     

Layered D2D NOMA

This paper investigates a layered power allocation(PA)non-orthogonal multiple access(NOMA)scheme for device-to-device(D2D)relaying networks,where the strategy of partial data transmission at relay nodes are adopted to improve the efficiency of resources.In addition,to satisfy different quality-of-service(QoS)requirements from multiple users,layered and grouped manners are involved.Moreover,the closed-form expressions in terms of the sum-rate(SR)and outage probability of the proposed scheme are derived for independent Rayleigh fading channels,which demonstrates our theoretical analysis.Both analytical and simulation results are provided to show the superiority of our proposed scheme compared with existing works.     

全双工中继网络的功率分配优化

针对全双工(FD)放大转发中继系统中自干扰造成的符号错误率(SER)性能门限问题,提出了FD放大转发中继系统功率分配优化方案。在考虑自干扰存在的环境下,对系统模型进行了数学分析,推导了中断概率和SER的表达式,制定了基于最小SER准则的优化问题,求出了次优的功率分配比。利用Matlab工具对FD放大转发中继系统SER进行了仿真,证明了该功率分配优化方案的有效性。     

Distributed Adaptive Power Allocation for Wireless Relay Networks

In this paper, we consider a 2-hop wireless diversity relay network. We explore transmit power allocation among the source and relays to maximize the received signal to noise ratio (SNR) at the destination. We consider two relay protocols, "amplify and forward" (AAF) and "decode and forward" (DAF) and design the respective power allocations for both uneeded and coded systems. For a 2-hop relay system with one relay node, we derive a closed-form power allocation solution and, based on it, we propose a relay activation condition. If and only if the fading channel coefficients satisfy this condition, the relay transmits the signals to the destination; otherwise, the relay will stay in the idle state. For a system with more than one relay node, general closed-form power allocation solutions based on an exact SNR expression are difficult to derive; we hence, calculate a SNR upper bound and derive a sub-optimum power allocation solution based on this bound. The simulation results show that for a 2-hop diversity relay channel with one relay node the proposed adaptive power allocation (APA) scheme yields about 1- 2 dB SNR gains compared to the equal power allocation. This SNR gain increases monotonically as the number of relays increases     

Low Complexity User Selection and Power Allocation for Uplink NOMA Beamforming Systems

Wireless Personal Communications - In this paper, we develop user selection and power allocation methods for NOMA systems equipped with multi-antenna to enhance the sum capacity of the uplink. The...     

基于中继系统的功率分配研究

首先对现有的中继系统功率分配模型进行阐述,然后对其所涉及的问题进行分类,并对近年来国内外在该方向的研究成果进行总结和分析,最后进一步阐述中继系统中功率分配亟待解决的问题和今后的研究方向.     

Optimal Power Allocation and Harvesting Duration for NOMA Systems in the Presence of Nakagami Channels

In this paper, we derive and optimize the total throughput of non orthogonal multiple access (NOMA) with energy harvesting. The source S harvests energy from radio frequency signal received from node A. The source uses the harvested energy to transmit data to N NOMA users classified using instantaneous or average power of channel gains. We optimize the powers allocated to NOMA users and harvesting duration to maximize the total throughput. We also derive packet waiting time and total delays for all NOMA users. We optimize powers allocated to NOMA users and harvesting duration to minimize a combination of total delays of all users. Our results are valid for Nakagami channels with arbitrary positions of users.

     

D2D通信的联合资源分配和功率控制方法

设备到设备(D2D)通信对未来蜂窝网络是一种很有前途的技术,它可以有效地提高系统的吞吐量和延长用户设备的电池寿命。然而,在蜂窝网络中,D2D通信共享频谱会造成干扰。为消除干扰,充分利用D2D通信的优势,提出了一个联合的频谱资源分配和功率控制(RAPC)方法,该方法能够实现总吞吐量最大化,同时保证D2D用户和蜂窝用户所需的最小速率。提出的资源分配和功率控制的优化问题,通过量子粒子群(QPSO)得到近似优化方案的最优解,其中的量子粒子代表资源分配和功率控制的方法,同时制定惩罚函数删除不可行的方法。仿真结果表明,该方法具有更好的性能、系统吞吐量、功率效率和最小速率比其他方法令人满意。     

Joint Relay Selection and Power Allocation for Cooperative Cellular Networks

The principal purpose of this paper is to develop a joint relay selection and power allocation algorithm in cooperative cellular networks with multiple users assisted by multiple relays. By solving a rate optimization problem, we can obtain the optimal solutions and the distributed implementation based on the primal-dual decomposition. An admission control algorithm is also presented when there exists the minimal rate requirement for each user. Simulation results indicate that the algorithm with joint design is superior to the existing ones with isolated design in large total transmission rates and small deviations. Moreover, with the admission control algorithm, the rate requirements for users participating in cooperation are also satisfied.     

Optimized Power Allocation for a Cooperative NOMA System with SWIPT and an Energy-Harvesting User

ABSTRACT

This paper investigates the solution to an optimisation problem to minimise the total transmission power at the transmitter in a cooperative non-orthogonal multiple access (NOMA) system with simultaneous wireless information and power transfer (SWIPT) and an energy-harvesting user. First, we formulate the optimisation problem to obtain the minimum transmission power at the transmitter under the constraints of minimum signal-to-interference-plus-noise ratio and minimum energy harvesting. Since the problem is not convex, we transform it into a bi-level optimisation problem. Then, conditions to guarantee the feasibility of the problem are provided, and we derive the analytical optimal solution via the Lagrange method meeting Karush–Kuhn–Tucker optimality conditions to solve the lower-level variables of the inner convex problem. Second, we use particle swarm optimisation to find the approximately optimal values of the upper-level variables. Next, we present two baseline schemes based on orthogonal multiple access (OMA) and equal power splitting for performance comparison with the proposed cooperative NOMA system with SWIPT. Finally, simulation results show that cooperative NOMA with SWIPT can reduce the transmit power at the transmitter, compared to two baseline schemes: OMA and EPS.     

面向用户体验的多小区混合非正交多址接入网络资源分配方法

该文研究了多小区混合非正交多址接入(MC-hybrid NOMA)网络的资源分配.为满足异构用户的服务体验,以最大化全网综合平均意见评分(MOS)累加和为目标,考虑基站选择、信道接入和功率资源分配的联合优化问题,该文提出一种用户、基站和信道3方的2阶段转移匹配算法,并根据用户MOS进行子信道功率优化.仿真结果表明所提多小区混合NOMA网络资源分配方案能有效提升全网用户服务体验和公平性.     

Resource Allocation Schemes in D2D Communications: Overview,Classification, and Challenges

Device-to-Device (D2D) communications is predicted to be a major part of 5G wireless communications due to its benefits such as flexible connectivity and unloading of traffic burden off the cellular networks. However, interference scenarios in D2D communications are usually more complicated than conventional wireless communications, e.g., spectrum reuse is commonly involved in D2D communications, especially when it works as an underlay. Therefore, how to coordinate the challenges of significant interference with the demand of higher data rates under the constraints of efficient energy consumption and spectrum utilization has become a haunting problem in our way to the ideal performance of wireless communications system. The solution resides in multiple resource allocation techniques in D2D communications as each of them attempts to solve or optimize one or several essential elements in the system. In this paper, a survey of resource allocation schemes in D2D communications is presented. We discuss the optimization classification including objectives, constraints, problem types and solutions. This paper also highlights system characteristics. Finally, future research challenges are outlined.     

Ambient Backscatter Communications over NOMA Downlink Channels

In this paper,we investigate the performance of commensal ambient backscatter communications(AmBC)that ride on a non-ortho go nal multiple access(NOMA)downlink transmission,in which a backscatter device(BD)splits part of its received signals from the base station(BS)for energy harvesting,and backscatters the remaining received signals to transmit information to a cellular user.Specifically,under the power consumption constraint at BD and the peak transmit power constraint at BS,we derive the optimal reflection coefficient at BD,the optimal total transmit power at BS,and the optimal power allocation at BS for each transmission block to maximize the ergodic capacity of the ambient backscatter transmission on the premise of preserving the outage performance of the NOMA downlink transmission.Furthermore,we consider a scenario where the BS is restricted by a maximum allowed average transmit power and the reflection coefficient at BD is fixed due to BD’s low-complexity nature.An algorithm is developed to determine the optimal total transmit power and power allocation at BS for this scenario.Also,a low-complexity algorithm is proposed for this scenario to reduce the computational complexity and the signaling overheads.Finally,the performance of the derived solutions are studied and compared via numerical simulations.     

Hybrid Multihop Relay Protocol Using Dynamic Power Allocation for LTE-Advanced System

In this paper, an adaptive relay scheme of hybrid relay system is proposed based on channel state information of the received signal-to-noise ratio (SNR) at the relay node. hybrid relay system is comprised of amplify-and-forward, decode-and-forward and demodulate-and-forward together in cooperative networks. The relay protocols are selected adaptively, on the basis of power allocation (PA) constraint, or the SNR value at previous hop. Thus multihop performance of the relay system can be improved by applying PA allocation scheme. The simulation results show that the performance of the novel hybrid relay protocol can be improved significantly compared to the conventional hybrid system in terms of error performance and link efficiency.     

BER Analysis of NOMA with Max-Min Relay Selection

In contrast with orthogonal multiple access(OMA) technologies,non-orthogonal multiple access(NOMA) technology can achieve higher spectral effi-ciency and suppor...     

Resource and Power Allocation for OFDM-Based Device-to-Device Communications in a Multicell Environment

Journal of Communications Technology and Electronics - We investigate the optimal resource and power allocation for device-to-device (D2D) communications in a multicell environment. When D2D links...     

Dual-Hop Non-regenerative OFDM Relay Systems with Chunk-Based Power Allocation

In this paper, we propose dual-hop non-regenerative Orthogonal Frequency Division Multiplexing (OFDM) relay systems without signal buffering and processing delay due to Fast Fourier Transform (FFT) and Inverse FFT (IFFT) at the Relay Node (RN). One scheme uses per subcarrier Power Allocation (PA) at Source Node (SN) and per chunk PA at RN to improve the achievable rate. Another scheme employs per chunk PA at both SN and RN. Numerical results in mobile communication environments show that both schemes improve the achievable rates compared to conventional simple amplify-and-forward relay systems with per subcarrier PA at RN. In particular, the latter scheme can obtain almost the same or slightly higher achievable rates by selecting an appropriate chunk size in severe frequency selective channel and by setting any chunk size in highly frequency-correlated channels. Therefore, chunk-based PA at both SN and RN can be found a beneficial PA for dual-hop OFDM relay systems in terms of competitive achievable rates and relatively small amount of required channel information to calculate allocated power.     

空时编码协作中的中继选择与功率分配联合方案

提出了一种空时编码协作中的中继选择与功率分配联合方案,称为DD(Destination Decision)方案.该方案由目的终端根据协作终端的信道状态信息进行中继选择与功率分配,并决定各中继发送STBC编码矩阵的哪一列,从而避免了通过中继之间的信息交互进行中继选择的冲突.理论分析和仿真结果表明,此方案在保证分集阶数和误码率性能的同时,提高了系统容量.     

一种适用于密集车辆V2X网络的中继节点选择和功率分配优化方法简

密集车辆的V2X网络中由于车辆相对位置快速变动,需要低复杂度的快速中继节点选择算法和功率分配优化算法。本文利用V2X网络节点定期广播的心跳信息,提出了一种基于信道容量运算的中继节点选择和功率分配优化方法,避免了大量的循环迭代,满足V2X网络的要求。