Energy-efficient resource allocation scheme for device-to-device communication underlaying LTE-A uplink

To cope with the co-channel interference between cellular links and device-to-device (D2D) links concurrently transmitting with the long term evolution-advanced (LTE-A) uplink spectrum,a joint resource allocation scheme was pro-posed to maximize the global energy efficiency of D2D links.The above problem can be decomposed into the power control subproblem and the channel assignment subproblem.Specifically,the power control subproblem can be optimally solved with the help of Dinkelbach method and Lagrange duality.Based on the above results,the channel assignment subproblem turns out to be the set packing problem which was generally NP-hard problem,Therefore,a heuristic algo-rithm was further devised to achieve a tradeoff between performance and complexity.Simulations show that the proposed joint resource allocation scheme outperforms the ones where only single resource variable is optimized,and it achieves the polynomial-time complexity at only minor performance loss when compared to the global optimum.     

QoS-aware scheduling algorithm in relay-assisted LTE-A system

This paper details on the uplink scheduling algorithm for long term evolution advanced （LTE-A） system with relays. While emulating quality of service （QoS）-aware services with different bit-rate and delay budget requirements for the upstream direction, a new QoS-aware scheduling algorithm for in-band relays is proposed. In this work, an improved scheduling metric calculation method and bit-rate guarantee scheme is applied. Moreover, this algorithm proposes an efficient scheme for the backhaul link allocation which allows information of the most backlogged users to be transmitted first. Finally, this paper concludes with simulation results to demonstrate how the proposed resource allocation strategy improves the performance of the system.     

LTE-A多小区中继网络两跳速率匹配资源分配算法

针对中继网络的两跳特性,提出一种多小区中继网络两跳速率匹配资源分配算法。首先,在第一个子时隙内各小区独立地为小区中所有用户分配子载波,并根据子载波分配结果,建立基于非合作博弈的功率分配模型;然后,由第一跳资源分配结果对第二跳速率匹配,自适应地为中继分配资源以满足边缘用户的速率需求。仿真结果表明,该算法在满足边缘用户速率需求的前提下,进一步提高了中心用户的吞吐量,同时降低了系统的发射功率,从而提升了系统性能。     

一种基于多点协作的上行资源调度方式

介绍了基于多点协作的上行资源调度方式。从边缘用户与中心用户判定、无线资源分配模式选择、天线设置与接收数据处理和系统仿真结果四个方面进行了论述。重点分析了中心用户与边缘用户区分标准的设定和资源分配、频选模式的频选度量值设定以及多点协作方式的联合接收数据处理等问题。仿真结果表明,通过合理设置和调整系统的控制参数,多点协作可以有效地降低系统误码率、提升系统吞吐量。     

LTE-A中继场景下切换的安全处理研究

中继作为LTE-A的关键技术之一,既能优化网络覆盖,还可以提高系统容量。然而中继的引入也为系统带来了诸多安全挑战。分析了中继部署场景下用户终端切换时的安全问题,给出不同切换场景模式的安全解决方案,以保证切换后通信的正常进行,并且通过建立Petri网络模型对所设计流程进行了分析。最后,对移动中继切换时的安全处理进行了讨论。     

LTE-A上行链路中单用户MIMO的球形译码算法性能分析

多输入多输出(MIMO)系统的接收端需要有效的检测算法以处理衰落和空间复用干扰等削弱效应,而算法的性能和复杂度等特性会随不同的应用场景有所变化,因而从这些角度评估和比较不同算法对于MIMO系统的实现具有重要意义。针对LTE-A上行链路中单用户MIMO的应用场景,通过分析现有文献中的球形译码(SD)算法及相关方法,以及对工程可实现性的考量,引入了一种将基于单树搜索的SD与迭代干扰消除结合运用的实现方案,并在遵循3GPP标准的上行仿真平台中对其进行了性能评估,观察了SD相对于MMSE的性能增益及相关趋势,进而为SD算法的工程实现提供参考依据。     

基于协作中继的LTE-A干扰对齐技术研究

为满足下一代移动通信系统高速率传输的要求,LTE-A系统引入了无线中继技术,用户终端可通过中继节点接入网络以获得高质量的服务。但是随着中继节点及用户的增加会导致系统的同道干扰更加突出,成为限制LTE-A网络容量的主要因素。因此,需要研究有效的干扰抑制技术以增强网络性能。近年提出的干扰对齐技术能够获得干扰网络的最大自由度并可达其最优容量。研究了基于低秩干扰空间的多小区干扰对齐技术,然后将该算法推广到LTE-A中继网络,提出了基于协作中继的LTE-A干扰对齐方案。仿真结果表明,提出的干扰对齐技术能够有效提高LTE-A中继网络容量。     

Graph theory based physical cell identity self-configuration for LTE-A network

Self-configuration of physical cell identity (PCI) is a key feature for the long term evolution advanced (LTE-A) network. The PCI is used to identify the different cells in the system, becoming an essential cell configuration parameter. Considering the uncoordinated deployments of the evolved Node B (eNodeB) and the limited number of PCI, the PCI assignment for cells would be quite complex. This paper presents and puts forward a graph theory based centralized PCI self-configuration scheme (GT-PCIS). The PCI self-configuration problem is mapped to the well-known minimum spanning tree (MST) problem in order to optimize the PCI reuse distance and decrease the multiplexing interference throughout the entire network. The proposal provides a greedy search to make the locally optimal selection of PCI at each stage, and to achieve a global optimum. To demonstrate the algorithm validity, performances of GT-PCIS and manual configuration are evaluated. Simulation results show that the proposed GT-PCIS outperforms other configuration algorithms even under the condition of severe PCI deficiency.     

基于中继技术的LTE-A终端省电方案

利用LTE-A协议对中继技术的支持,提出将中继协议集成到移动终端内部,在充电状态下切换为中继节点,为附近其他移动终端提供信号中继服务,从而达到省电的目的。当附近多个移动终端切换为中继节点时,使用V-MIMO技术与基站连接以帮助其他移动终端提高信号质量和速率。     

LTE-A中异构网络的切换分析

在传统网络数据流量爆发性增长、频谱效率已接近极限值的形式下,异构组网是增加网络容量、提高数据速率的有效方式。LTE-A系统中异构组网引入低功率节点,缩短了网络与用户间距离,提高了无线链路质量和频谱效率,逐渐成为LTE-A系统中的关键技术之一,但同时也带来复杂的移动性管理等问题。在深入分析3GPP E-UTRA协议规范的基础上,首先建立了LTE-A MacroPico异构网络拓扑模型,然后对Macro-to-Pico和Pico-to-Macro双向切换概率进行了分析和仿真。在此基础上,给出了用户及其相关网络参数对于切换成功概率的影响分析。     

Effective resource scheduling scheme considering scheduling relevancy for downlink joint transmission system

Coordinated multi-point(CoMP) transmission is a promising technique to improve both cell average and cell edge throughput for long term evolution-advanced(LTE-A).For CoMP joint transmission(CoMP-JT) in heterogeneous scenario,if joint transmission(JT) users are firstly scheduled,other non-JT users will not be allocated sufficient resources,i.e.,scheduling relevancy exists in the users under different cells in the same coordination cluster.However,the CoMP system throughput will decline remarkably,if the impact of scheduling relevancy is not considered.To address this issue,this paper proposes a novel scheduling scheme for CoMP in heterogeneous scenario.The principles of the proposed scheme include two aspects.Firstly,this scheme gives priority to user fairness,based on an extended proportional fairness(PF) scheduling algorithm.Secondly,the throughput of the coordination cluster should be maintained at a high level.By taking the non-CoMP system as a baseline,the proposed scheme is evaluated by comparing to random PF(RPF) and orthogonal PF(OPF) scheme.System-level simulation results indicate that,the proposed scheme can achieve considerable performance gain in both cell average and cell edge throughput.     

LTE-A系统中一种新的干扰计算方法

为了实现LTE-A要求的高速率和高频谱效率,需要对蜂窝小区进行更加精确的预测或干扰控制。文章提出了一种基于多小区集中式调度方案基础上的小区间联合资源分配的线性建模方法。由于方程组里包括了干扰功率、发射功率、目标SINR等参数,是一个比较精确的模型,且便于计算机实现。     

Resource scheduling scheme with QoS support in two-hop relay-enhanced OFDMA systems

As the system performance is obviously improved by introducing the concept of relay into the traditional orthogonal frequency division multiple access(OFDMA)systems,resource scheduling in relay-enhanced OFDMA systems is worthy of being studied carefully.To solve the optimization problem of achieving the maximum throughput while satisfying the quality of service(QoS)and guaranteeing the fairness of users,a novel resource scheduling scheme with QoS support for the downlink of two-hop relay-enhanced OFDMA systems is proposed.The proposed scheme,which is considered both in the first time sub-slot between direct link users and relay stations,and the second time sub-slot among relay link users,takes QoS support into consideration,as well as the system throughput and the fairness for users.Simulation results show that the proposed scheme has good performance in maximizing system throughput and guaranteeing the performance in the service delay and the data loss rate.     

LTE-A空口监测仪表NAS协议监测方案研究

在熟悉NAS(Non-Access Stratum,非接入层)协议基本概念以及功能的基础上,介绍了LTE-A空口监测仪表的功能,并设计了针对NAS协议的监测方案。针对NAS消息的特殊结构,本着高效的原则监测方案中设计了具有模块化思想的NAS协议的解码方案。针对常用网络监测技术中CDR(Call Detail Record,呼叫详细记录)合成时效性不足的问题,本监测方案中采用了基于缓存索引的hash算法并引入了超时管理机制来完成CDR的合成,在提高合成效率的同时提高了合成的有效性以及准确性,对于LTE-A网络质量的评估和分析具有意义。     

LTE-A中自适应多流波束赋形算法研究

多流波束赋形技术是LTE-Advanced中采用的多天线增强技术。采用单用户多流波束赋形技术,可以使得单个用户在某一时刻可以进行多个数据流传输,在提升系统性能上表现出极大优势。提出一种LTE-Advanced中下行单用户自适应多流波束赋形算法,基站端基于接收模型对下行链路容量进行预估计,在一定信噪比要求的条件下,以信道容量最大化准则选择波束赋形流数。仿真结果表明,自适应算法增加了波束赋形系统的灵活性,能够有效提高LTE-Advanced系统中下行链路性能。     

LTE-A下行CoMP反馈开销减小方案

简单介绍了LTE-Advanced的关键技术之一——协作多点传输技术,通过分析该技术,指出了在下行反馈方面存在的反馈开销巨大的问题。通过对比现有的方案,并在现有方案基础上提出了新的反馈方案,从而在减小反馈开销方面得到很大提升。     

Uplink scheduling scheme for cloud service based on software-defined wireless network

A LTE uplink scheduling scheme matching the features of wireless cloud services was proposed for the SDWN (software-defined wireless network). The scheme first solved the resource allocation problem by using the binary integer programming method, and then calculated the optimal transmission rate of cloud services in each time slot using the method of dynamic programming, finally adjusted the transmission rate of cloud services proportional to the current channel status using QoS control method in the framework of SDWN. The proposed scheme minimizes the energy con-sumption of cloud services while ensuring the transmission rate demand of multiple services. The performance of the al-gorithm is verified by simulation.     

区分服务网络中自适应加权调度方案的研究

针对现有区分服务网络中多服务间带宽公平性问题，提出了一种自适应加权调度方案。该方案通过对本地节点缓存区指标的定期测量，计算得到在各队列间公平分配剩余带宽的调度权值。仿真结果表明，该方案可以在网络负载变化时自适应的快速调整到理想调度值，有效改进了带宽分配的公平性。     

面向网络性能优化的虚拟计算资源调度机制研究

针对基于Xen的vCPU调度机制对虚拟机网络性能的影响进行了深入研究和分析。提出一种高效、准确、轻量级的网络排队敏感类型虚拟机（NSVM）识别方法,可根据当前虚拟机I/O传输特征将容易受到影响的虚拟机进行准确识别和区分。进而设计一种新型虚拟计算资源调度和分配机制Diff-Scheduler,将不同类型虚拟机的vCPU实施分池隔离调度,同时提高NSVM类型虚拟机vCPU的调度频率。原型系统实验结果表明,相比Xen默认的调度机制,Diff-Scheduler能够大幅提高虚拟机网络性能,同时保证计算资源分配的公平性。     

中继蜂窝网络中动态无线资源分配方案

提出一种中继蜂窝网络中基于动态复用分割的无线资源分配方案。该方案在所设计的帧结构基础上,从时间域和频率域进行联合的资源分配。其基本思想是通过小区间的协作使频带资源可以最有效的复用来提高系统性能。仿真结果论证了该方案在小区容量方面可以获得较大的增益。