应用于中继蜂窝网络的混合式协作中继选择算法

提出一种应用于中继蜂窝网络的混合型协作中继选择算法(HCRSA). 当用户采用中继传输时,为实现协作通信,HCRSA算法根据当前小区中的用户密度情况,动态地选择了基站和中继节点之间的协作传输,或中继节点和协作用户之间的协作传输. 仿真结果表明,与固定中继选择相比,HCRSA能根据网络中的实际情况选择不同的协作中继机制,充分利用协作中继来有效提高用户容量,提升系统性能. 性能。     

OFDMA蜂窝中继网络中继选择算法研究

提出两种用于正交频分多址(OFDMA)蜂窝中继网络的中继选择算法,一种在限制数据速率情况下,以用户能量消耗最小化为优化目标;另一种在限制花费能量情况下,以系统频谱效率最大化为优化目标.同时,加入了小区内负载平衡处理机制.首先将基于定价的多小区非合作功率分配博弈模型引入蜂窝中继网络中,得到每一跳的功率-效用对;然后将其合并得到每条路径的功率-效用对;最后依据不同的优化目标,在可行路径的功率和效用之间进行折中中继选择.仿真结果表明,相对于基于信干噪比(SINR)的中继选择算法,提出的两种中继选择算法分别达到了其优化目标,获得了相应的性能增益.     

整体优化的吞吐量预测中继选择策略

提出了一种蜂窝网络中关于移动中继的选择方案,将小区内的用户按照下行路径损耗分为一跳用户和两跳用户.一跳用户由基站直接对其分配资源,两跳用户采用整体优化的吞吐量预测中继选择算法选择空闲用户作为中继节点.该算法全面考虑了带宽与信道质量对通信速率的影响,以两跳用户所在接入链路与回程链路吞吐量相等为原则主动调节两跳用户带宽分配比例,并且通过匈牙利算法计算出系统吞吐量最大时的最佳匹配矩阵.仿真结果表明,该算法能够有效提升边缘用户吞吐量和频谱利用率.     

一种基于设备效用值的中继选择算法

对于非正交多址接入(NOMA)协作网络,传统的基于最佳距离选择、最大中继速率的中继选择算法虽然可以提高系统运行效率,但都忽视了设备效用问题。因此,提出了一种基于设备效用值的D2D通信中继选择算法。该算法综合考虑中继通信速率、设备位置及设备能耗等多种因素,将中继设备原有电量和协作转发后的剩余电量作为衡量指标。仿真结果表明,在D2D实际应用场景中,与传统算法相比,采用基于设备效用值的中继选择算法,通信系统吞吐量更高。     

两跳中继网络的资源分配算法

对于具有中继节点的蜂窝系统,用户的实际速率受限于基站与中继之间链路(第一跳链路)以及中继与用户之间链路(第二跳链路)的吞吐量.单独考虑其中某一跳链路的资源分配,会降低系统的整体性能.因此,针对中继网络,设计了基于两跳链路吞吐量平衡的正向和逆向功率分配算法.其中正向分配算法在进行第二跳链路资源分配时,考虑了第一跳链路的影响.而逆向分配算法则是将第二跳链路的吞吐量作为第一跳链路资源分配的依据.仿真结果表明,设计的算法有利于克服两跳中继网络的瓶颈问题.尤其是逆向分配算法由于充分考虑了用户的最优速率情况,在提高系统吞吐量的同时还减少了能量消耗.     

面向业务服务质量的中继系统资源分配算法

为了提高正交频分复用中继系统下行链路的吞吐量,满足用户对服务质量的需求,基于比例公平算法给出一种面向业务服务质量的资源分配算法。先根据用户在队列中的等待时延和用户对速率的需求,设计出时延因子和速率因子,并以此在时域阶段计算出不同用户优先级,最后在频域阶段根据用户的优先级分配资源。仿真结果表明,与原比例公平算法相比较,新算法吞吐量可提升35%到50%,用户公平性指数可提高13%,用户满意度也有增加。     

电力物联网D2D通信中模式预选的多播重传技术

针对电力物联网D2 D通信中的模式预选问题,提出多播重传机制.首先,通过分析D2 D传输的集中式和分布式2种重传方案的优势和不足,提出一种新的基于重传模式预选的D2 D多播重传方案.新方案通过簇头汇总D2 D多播ACK状态和簇内链路质量,避免了集中式方案中上行汇报信令开销太大的问题;同时,通过让簇头来决定重传方案后再上报基站的方式,避免了分布式重传方案中预留资源带来的资源浪费问题.簇头充分考虑D2 D链路差异,根据D2 D链路质量自适应地选择最优传输节点,可充分利用D2 D链路的多信道分集增益.理论分析和计算机仿真验证方案在信令开销和传输效率方面的有效性.     

基于不完全信道信息的D2D功率分配算法

针对蜂窝与终端直通(Device-to-device,D2D)混合网络中的不完全信道状态信息(Channel state information,CSI),提出了一种基于不完全CSI的最优功率分配算法。利用拉格朗日乘数法推导出了最优功率分配解的闭式表达式。相对于传统的最大发送功率分配方案,该最优解受信道信息误差的影响较小,具有较好的鲁棒性。仿真结果表明,本文算法可以节约发送功率,并得到更大的接收信噪比。     

协作通信网络中基于Lagrange算法的中继选择和功率优化方案

协作通信技术可以有效获取空间分集,并进一步改善系统的性能。为最小化多中继解码转发(decode-and-forward,DF)协作通信系统的总功率,同时满足系统要求的数据传输速率,提出了一种基于Lagrange算法的中继选择和功率分配的联合优化方案。首先根据信源与中继的瞬时信道状态信息(channel state information, CSI)使信源的发送功率最小化,然后选择出最大的可解码中继集合,再利用Lagrange算法对中继功率进行优化,根据得到的信源和中继的功率分配,选择出最佳中继集合,达到最小化系统总功率的目的。仿真结果表明,相对于直传方案和机会中继(opportunistic relay selection, ORS)方案,本研究中总功率消耗明显减少。     

Optimal power allocation and optimal relay selection for D2D communication

Cellular users can be regarded as relay nodes in cooperation with the Device-to-Device (D2D)communication so as to lower the cost, improve spectrum efficiency and solve the problems of network coverage, as well as improving service quality. In this paper an optimal power allocation and optimal relay selection algorithm based on network coding is proposed for using cellular users in the bidirectional relay nodes system. By fixing the total power of the D2D link to be transmitted, this algorithm optimizes the transmission power of each node, and selects the relay node which can maximize the channel capacity of the D2D link as the best relay node. Simulation results show that compared with other protocols, the proposed protocol can significantly improve the channel capacity of the D2D link.     

D2D communication in a cellular network based on link adaptation with truncated ARQ

A device-to-device （D2D） communication mode underlaying cellular network in a single- cell environment is introduced. A practical method based on link adaptation with automatic repeat request （ARQ） is presented. Link adaptation technique, which combines adaptive modulation and coding （ AMC ） with truncated ARQ, can maximize the cellular UEs＇ data rate under prescribed delay and performance constraints. The proposed method can maximize the total transmission rate when an outage probability is determined. Numerical results show that with proper power control, the in- terference between the two links can be coordinated to increase the sum rate without overwhelming the cellular service.     

Resource reusing selection scheme for device-to-device communication underlaying LTE-A networks

Device-to-Device (D2D) communication underlaying LTE-A cellular networks is effective to improving spectral efficiency and offload traffic of the base station by reusing cellular resources. However, the mutual interference between D2D and cellular communications can degrade the performance of both D2D and cellular users. In this paper, a resource reusing selection scheme based on minimizing power increase is proposed, which enables selective compensation for signal to interference plus noise ratio (SINR) diminution caused by interference. Simulation results demonstrate that the proposed scheme notably improves the access grant probability of D2D users and increases the link spectral efficiency of D2D and cellular networks, without sacrificing the quality of cellular and D2D communication.     

Design of the D2D multicast transmission scheme in the LTE communication system

In order to improve spectrum efficiency and transmission reliability of the LTE communication system, its terminal users can be divided into the D2D communication cluster. Specially, the multicast transmission of data packets in the LTE system can be realized through two hop transmissions, namely, the base station multicasts data packets to all cluster-heads and each cluster-head in the D2D communication cluster broadcasts the received packets. Considering that the links may be unreliable in the D2D communication cluster, the ARQ retransmission algorithm based on network coding is adopted. By establishing the lost-packet list, the cluster-head operates the lost-packets by network coding, and broadcasts the encoded packets to reduce the number of retransmission. Performance analysis and simulation results show that the proposed scheme can achieve almost the same transmission efficiency as the existing scheme, but has a lower computational complexity. Compared with the traditional multicast retransmission scheme based on network coding in the cellular communication mode, the scheme only retransmits the lost-packets in D2D cluster, to reduce the pachets transmission number of base stations and decrease the spectrum resource consumption of the cellular network effectively at a high packet loss rate.     

提高LTE下含D2D通信的蜂窝网络公平性方案

设备间(D2D)通信可以提高频谱效率,但同时可能对现存的蜂窝网络产生干扰. 为了减小D2D用户对蜂窝系统公平性的破坏,提高蜂窝系统的整体性能,提出改进的比例公平(IPF)干扰控制方案,在保证蜂窝用户和D2D用户的服务质量需求的前提下,为每一个D2D对选择最佳的蜂窝用户来共享频谱资源. 通过数值结果分析显示,IPF方案比起之前的方案,能够有效改善蜂窝系统的公平性和吞吐量.     

Energy-aware resource allocation for underlaid D2D multicast

The Device-to-Device (D2D) communication underlaying cellular network is a promising component to improve the spectral efficiency for the system and lower down energy consumption for mobile terminals. Besides, in the D2D-aided content delivery scenario, it is potential to enhance the system capacity and individual quality-of-service (QoS) experience when D2D multicast is further enabled, but due to the battery-driven feature of mobile relays and the co-channel interference between cellular and D2D links, the optimization of energy conservation should be addressed. So, we propose a bipartite graph based resource allocation to minimize the total power consumption at the mobile relays under the individual QoS requirement by incorporating channel assignment and power control, and we also leverage the optimization of energy saving for system capacity.     

中断概率分析下的终端多跳直通通信路由选择

提出一种蜂窝与终端自组织混合网络中多跳直通通信的路由选择方法. 首先给出混合网络下的多跳直通通信的干扰模型和信道模型,并考虑了蜂窝终端对直通通信终端的干扰范围. 基于模型分析并得到D2D通信下的中断概率公式,然后将此公式应用在多跳路由选择中,提出了一种多跳路由选择方法. 仿真结果表明,与其他路由算法比较,新提出的方法可以有效提高吞吐量.     

基于D2D通信的V2X资源分配方案

针对基于设备到设备(D2D)的汽车间通信复用蜂窝资源带来的干扰问题,考虑在满足车辆用户(V-UEs)的通信要求下,通过一个启发式算法最大化蜂窝用户(C-UEs)总的吞吐量.首先通过图着色原理将没有干扰的车辆分在同一簇;其次根据分簇结果,利用改进的匈牙利指派算法为V-UEs分配信道;最后通过调整功率最大化C-UEs总的吞吐量.仿真结果表明,此算法能够很好地解决车通信(V2X)的同层干扰和跨层干扰问题,在保证V-UEs通信可靠性的前提下,提高了频谱利用率.     

电力物联网中节能的免许可D2D接入算法设计

针对免许可频段的终端到终端（D2D）通信的功耗问题,进行功率和频谱的联合分配,以寻找使系统终端功耗最小的资源分配方式. 在免许可频段为D2D提出信道接入协议,该协议在许可信道的协助下确定D2D终端可使用的免许可信道及对应信道可使用的时隙资源. 建立以最小化系统总功耗为目标的优化问题,考虑D2D用户对的数据速率和对基站（BS）产生的干扰的限制. 该问题被建模为凸优化问题,利用内点法求解. 通过数值仿真,对免许可频段的D2D通信（D2D-U）的工作情况进行验证,证明利用该算法能够得到最优的分配结果.     

基于节点选择和功率分配算法的自适应调制协作通信系统

协作通信技术可以通过利用空间分集来改善系统的性能,特别是当信源节点已经知道信道信息时,可以获得相对于非自适应系统非常大的增益。提出一种基于自适应调制的协作通信方案,此方案结合了空时编码、功率分配和中继选择技术,在满足一定的误码率要求下可以提高系统吞吐量。通过与其它自适应、非自适应方案性能的比较,表明所提出的方案可以在很好地满足误码率要求的前提下,具有非常好的吞吐量性能。