基于斯塔克伯格博弈的联合中继和干扰的功率分配机制

在无线通信系统中,用户与窃听中继协作将导致信息泄露,为保证自身通信安全需向协作干扰者支付报酬购买干扰功率,导致自身效益降低。为了在安全通信的同时提高用户效益,提出一种基于斯塔克伯格的联合中继和干扰的功率分配机制。在窃听中继协作转发、空闲用户协作干扰的场景下,建立三方博弈的斯塔克伯格博弈模型:将通信用户建模为功率购买者,窃听中继和空闲用户建模为功率出售者,有效刻画了安全与效益的折中关系。仿真结果表明,所提联合功率分配方案会在数次迭代后收敛到所有节点收益最大值,同时也是发送方通信安全容量的最大值,比中继全功率发送时提高了0.2(bit·s~(-1))·Hz~(-1),提高用户安全性能。     

多用户对双向中继网络的中继和用户选择策略

通过对多用户对多个可选中继组成的双向中继网络进行权重二部图建模,并利用信道状态信息合理设计权重,从而将以最大化系统总速率为目标的中继和用户对选择策略问题等效为权重二部图的最大权匹配问题。利用图论最大权匹配算法（匈牙利算法）,提出了最大权匹配选择策略。并进一步同时基于最大权匹配算法和用户对公平性,提出了最大权匹配轮询策略和基于数据序列因子的最大权匹配策略。仿真结果证明,3种策略均提升了系统性能。     

基于议价博弈论的无线协作中继网络性能改进算法

针对自私性无线协作中继(CR)网络中的放大再中继(AF)和解码再中继(DF)协议,分别给出 公平且有效率的协作中继功率分配方案。两种方案虽然具体研究内容有差别,但有着共同 的研究策略。首先,将节点间的协作功率选择问题建模为纳什议价博弈问题(NBP);然后, 通过求取其纳什议价解(NBS)获得协作节点的共赢策略;最后,针对AF和DF协议分别给出计 算机仿真。仿真结果表明,所提出协作中继性能改进算法的效率性体现在所有协作节点在AF 和DF协议中均获得信号接收质量的提高,其公平性则体现在任意节点为其协作伙伴所贡献的 转发功率大小仅取决于对方为其带来的性能增益大小。     

无线协作网络中基于数据传输需求的分布式功率控制

在未来无线通信网络中,协作通信的性能依赖于通信资源的有效分配,比如中继选择和功率控制等.在本文中,我们建议了一个分布式买者和卖者博弈理论框架,以满足用户链路质量需求为基础,解决多用户协作通信中最优化中继选择和功率控制.本文联合考虑了源节点和中继节点的功率分配,进而优化源节点和中继节点的收益.这里提出的方法不仅有助于源节点找到相对位置较好的中继节点以及在源和中继之间进行最优化功率分配从而最小化源节点的支付,而且有助于相互竞争的中继节点提供优化的价格以最大化它们各自的收益.此外,这里的优化价格可以仅由局部信道状态信息和其他节点的能量价格决定.如果获得的中继节点总数增加,全网的能量消耗会更低.     

基于能量采集的译码转发中继系统功率分配算法

本文针对基于能量采集的译码转发（DF）中继蜂窝异构网络,提出了一种系统容量最大化的功率分配算法。中继和用户节点均采集由基站发送的射频信号的能量;利用采集到的能量,通过时分多址方式,用户节点经中继将信息发送给基站。在满足中继和用户节点采集能量的因果性限制及总功率受限条件下,构建了系统容量的优化模型。利用拉格朗日乘子法和KKT (Karush-Kuhn-Tucker)最优条件,为使系统容量最大化,对中继和用户功率进行分配;通过等效信道增益,将中继功率和用户功率联合优化问题简化为用户功率优化问题,然后通过次梯度算法获得功率最优解。仿真结果表明,与受限于中继和用户采集能量因果性的用户平均功率算法相比较,本文算法可以提高系统平均容量。      

不对称双向中继信道中的再生双向中继选择及功率分配

该文研究不对称双向中继信道下的被动式再生中继选择问题。首先,通过理论分析给出了传统3节点网络的可达速率域。然后,在瑞利衰落信道环境下,理论推导了系统中断概率的闭合表达式。接着,利用系统业务知识和信道状态信息,提出一种改进型的最大最小中继选择准则。进一步,研究中继端叠加信号的功率分配,提出了两种功率分配因子选择算法,并对所提算法进行了理论分析。仿真结果表明：通过被动式再生中继选择和功率分配可以显著提高系统的中断性能,在信道不对称情况下性能优势明显。     

一种联合中继节点选择的博弈功率控制算法

有效的资源分配在协同通信中占有举足轻重的地位,鉴于此,该文研究了其中的中继节点选择和功率控制问题,提出了一种联合中继节点选择的博弈功率控制算法。它的主要思想是从各节点信噪比的角度建立收益函数,并具体针对源节点和中继节点建立不同的代价函数。在认为每个节点都负责的前提下,通过调整各节点功率达到各自效用的最大化,并依据中继节点发送功率的策略空间,优化参与协同的中继节点集合。同时,该文还对纳什均衡的性能进行了数学分析。从仿真结果可以看出,所提算法在复杂度可接受的前提下,能使各节点间的功率得到合理有效的使用,确能改善系统性能。     

总功率受限下的双向多中继系统功率分配方案

针对放大转发双向多中继协同通信系统,提出了一种基于最大化最小双向速率准则的功率分配方案。将功率分配问题分解为用户节点功率分配和中继节点功率分配两部分,首先通过将多中继节点信道等效为单中继节点信道,简化了用户节点功率分配,然后应用矩阵变换实现了分布式的中继节点功率分配,减少了反馈开销,降低了计算复杂度。仿真结果表明,提出的功率分配方案在系统双向可达速率和误码率两方面指标均优于现有双向中继功率分配策略,而且性能增益随着中继数目的增加而提升。     

一种改进的中继节点选择方案

3GPP标准组织在2004年底启动了其长期演进(LTE)技术的标准化工作.上行传输方案采用带循环前缀的单载波频分多址接入(SC-FDMA)技术.对LTE上行链路进行仿真,实现无中继节点的直接传输.引入中继节点,通过传统最大路径损耗最小(LMP,least maximum pathloss)方案选取最优中继参与协作传输.重点分析并指出了传统LMP算法的缺点和不足,在此基础上提出了一种改进的中继节点选择算法,并结合考虑了源节点和中继节点的功率分配.从系统误码率和用户消耗功率两个方面对各传输方案进行了仿真分析.仿真结果表明LTE上行链路引入中继节点实现协作传输可明显提高系统的误码率性能.协作传输还节约了功率的使用,提高了用户的待机时间和功率效率.相比传统中继选择方案,改进后的LMP算法无论是从误码率还是功率消耗都得到明显改善.     

多中继协作通信系统容量分析及中继选择协作分集策略

本文针对多中继辅助通信系统,将系统建模为一个两跳通信链路,并进行了系统容量分析。针对两种特殊情况:用户端接收噪声方差远小于中继端接收噪声方差和中继端接收噪声方差远小于用户端接收噪声方差的情况,本文具体给出了系统传输容量上限与协作中继个数之间的关系。基于容量的分析,本文设计了两种中继选择策略。在第一种情况下,根据中继与用户间的信道特征值对多路数据流分别选取不同的中继子信道进行传输;在第二种情况下,选择一个信道条件最好的中继完成多路数据流的并行传输。仿真分析表明,不同的信道环境需要选择不同的中继选择策略。      

Distributed Relay Selection and Power Control for Multiuser Cooperative Communication Networks Using Stackelberg Game

The performance in cooperative communication depends on careful resource allocation such as relay selection and power control, but the traditional centralized resource allocation requires precise measurements of channel state information (CSI). In this paper, we propose a distributed game-theoretical framework over multiuser cooperative communication networks to achieve optimal relay selection and power allocation without knowledge of CSI. A two-level Stackelberg game is employed to jointly consider the benefits of the source node and the relay nodes in which the source node is modeled as a buyer and the relay nodes are modeled as sellers, respectively. The proposed approach not only helps the source find the relays at relatively better locations and "buy” an optimal amount of power from the relays, but also helps the competing relays maximize their own utilities by asking the optimal prices. The game is proved to converge to a unique optimal equilibrium. Moreover, the proposed resource allocation scheme with the distributed game can achieve comparable performance to that employing centralized schemes.     

Optimal Power Control in Cooperative Relay Networks Based on a Differential Game

In this paper, the optimal power control problem in a cooperative relay network is investigated and a new power control scheme is proposed based on a non‐cooperative differential game. Optimal power allocated to each node for a relay is formulated using the Nash equilibrium in this paper, considering both the throughput and energy efficiency together. It is proved that the non‐cooperative differential game algorithm is applicable and the optimal power level can be achieved.     

基于能量收集的多对双向MIMO AF中继系统的和速率分析

采用基于中继功率分配的能量收集方法,中继将接收到的部分射频信号转化为能量并利用收集到的能量放大和转发剩下的信号,通过在中继使用最大比合并/最大比传送的接收和预编码技术,推导出每个用户的遍历速率的下界表达式,然后研究了使所有用户和速率最大的最佳中继功率分配比.仿真结果说明了在最佳中继功率分配比的条件下可以得到最大的和速率,同时给出了和速率与中继天线数和用户对数的关系,并表明了在用户总功率一定的条件下,能量收集中继系统的性能优于传统的没有能量收集的中继系统.     

Distributed SNR-Based Power Allocation in Wireless Parallel Amplify-and-Forward Relay Transmissions Using Cournot Game

In wireless communications, power allocation plays a paramount role in sustainable network lifetime prolongation with quality-of-service and network interference reduction. This paper investigates a distributed power allocation problem in wireless parallel amplify-and-forward (AF) relay transmissions. Particularly, the objective is set to minimize the total transmit power while guaranteeing the signal-to-noise ratio (SNR) requirement at the destination node. The distributed SNR-based power allocation problem is formulated and modeled as a Cournot game. Moreover, a distributed SNR-based power allocation algorithm is proposed to solve the Cournot game. The proposed distributed SNR-based power allocation algorithm is proved to converge to a unique equilibrium. To evaluate the distributed method, a centralized optimal SNR-based power allocation algorithm is also proposed. Numerical results show that the proposed distributed SNR-based power allocation algorithm can achieve comparable performance to the centralized optimal SNR-based power allocation algorithm.     

A Stackelberg game for resource allocation in multiuser cooperative transmission networks

In this paper, we consider the problem of stimulating cooperation and resource allocation in cooperative transmission networks. We formulate this problem as a sellers' market competition where a relay is willing to share its resource with multiple users. We use a Stackelberg game to jointly consider the benefits of the relay and the users. Firstly, the relay determines the price of relaying according to the user demand. Secondly, the users purchase the optimal amount of resources to maximize their utilities. Although the Nash equilibrium, i.e., the solution of the game, can be obtained in a centralized manner, we develop a distributed algorithm to search the Nash equilibrium, which is more applicable in practical systems. Also, the convergence conditions of the algorithm are analyzed. Simulation results show, by using the distributed algorithm, the relay and the users could determine what price should ask for and how much bandwidth should buy, respectively. Copyright © 2010 John Wiley & Sons, Ltd.     

Competitive Resource Sharing Based on Game Theory in Cooperative Relay Networks

This letter considers the problem of resource sharing among a relay and multiple user nodes in cooperative transmission networks. We formulate this problem as a sellers’ market competition and use a noncooperative game to jointly consider the benefits of the relay and the users. We also develop a distributed algorithm to search the Nash equilibrium, the solution of the game. The convergence of the proposed algorithm is analyzed. Simulation results demonstrate that the proposed game can stimulate cooperative diversity among the selfish user nodes and coordinate resource allocation among the user nodes effectively.     

Power Allocation for Two-Way Relay System Based on Sequential Second Price Auction

In this paper, we consider a multiuser multi-antenna two-way relay system in which multiple pairs of partners communicate via a single relay node. The total transmit power of the relay node is shared by all pairs of partners. In order to allocate the limited power with both efficiency and fairness, we introduce a sequential second price auction as a mechanism to achieve such goals. First, we provide the system model and formulate the channel capacity of each pair. Then, we construct an algorithm which leads to the equilibrium of a sequential second price auction with full information assumption and sophisticated bidding strategy. The equilibrium result is used for allocating the relay power among pairs of partners. Finally, we provide the simulation results considering both randomness of user locations and time-varying nature of wireless channels, which show that the proposed algorithm has a good performance in total channel capacity, system efficiency, and fairness.     

C-V2X下车载安全数据两阶段组播的中继选择与功耗分析

车载通信业务的需求加剧了基站功率消耗,降低了其数据传输的可靠性.本文提出了一种蜂窝网络下基于两阶段组播的车载安全数据传输中继选择策略,以节约系统总功耗为前提来确定中继选择范围,计算出基站功耗最小的最优组播半径x₀,并选择距最优组播半径x₀最近的车辆作为中继.基于中继的社会属性建立基站群体和中继群体间的非对称演化博弈模型,设计了不影响安全数据传输的中继娱乐数据发送功率动态再分配的奖惩机制.仿真结果表明：当车辆数目超过临界值K_min时,本文提出的中继选择策略和奖惩机制,可在保证安全数据两阶段组播可靠性的同时,使基站功耗相比直接组播的功耗至少降低25%.     

多天线双向中继系统中的中继处理与资源分配策略

该文在多天线放大转发双向中继系统中,根据最小和均方误差(MSMSE)准则,以较小的复杂度得到了MSE最优的中继处理矩阵的闭合表达式。为综合利用空域和频域分集,探讨了OFDM双向中继系统的资源分配策略,提出了实现复杂度低的分层子载波配对策略和功率优化分配策略。仿真结果显示,所设计的中继处理策略在系统和速率和误码率性能上均明显优于其他双向中继策略,且性能随着中继天线数的增加而提升;结合功率分配的分层子载波配对策略能明显提升系统和速率,性能接近最优策略。     

An Energy-Efficient Relay Selection Strategy Based on Optimal Relay Location for AF Cooperative Transmission

In this paper, an energy-efficient optimal relay selection strategy which is jointly optimized with the energy-efficient optimal power allocation scheme for AF cooperative transmission is proposed. The relay selection criterion is the distance from the potential relay to the corresponding optimal relay locations where the minimum transmission power of the source, the relay or their total can be achieved. In order to determine the optimal relay locations, a universal algorithm with low computational complexity and easy implementation is also presented. Simulations are conducted to validate our theoretical analysis. The results show that with the relay selected by the proposed strategy, the cooperative transmission can achieve considerably high energy-efficiency.