多业务MIMO-OFDMA/SDMA系统跨层调度与动态资源分配

对多业务MIMO-OFDMA/SDMA 系统下行链路跨层调度与动态资源分配问题进行了研究.首先,在满足各种约束条件的前提下,以最大化系统吞吐量为目标建立了相应的优化模型;然后,提出了一种基于业务类型和子空间距离的用户分组算法,该算法采用聚类分析的方法在每个子载波上对配置有多根接收天线的用户进行分组,从而降低了调度时所需搜索的用户空间的维数;接着,基于所提出的用户分组算法并结合不同业务的优先级提出了一种新的跨层调度和资源分配算法,该算法充分利用跨层信息为每个子载波调度相应的用户组,并为调度到的用户分配相应的系统资源,从而通过最大化每个子载波的吞吐量近似实现了系统整体吞吐量的最大化.仿真结果表明,与现有的方案相比,所提算法更好地满足了不同业务用户的QoS要求,并获得了更好的吞吐量性能.     

OFDMA无线网络资源管理问题研究

综述了OFDMAN络中资源管理问题的研究进展。对OFDM系统物理资源分配的组合优化问题模型与几种典型算法进行了分析,讨论了物理资源分配与MAC层机会调度的跨层联合设计,指出了在OFDMA网络中机会调度算法设计的若干关键问题,展望了本领域的发展趋势,为资源管理方案的进一步研究提供借鉴。     

一种自适应的OFDMA系统下行分组调度算法

提出了一种适合于OFDMA（正交频分多址接入）系统的资源分配与调度算法,该算法利用物理层的信道信息和MAC层的队列状态信息,并综合考虑了数据分组传输的时延要求和业务的优先级,采取资源块与子载波分配相结合的资源分配方式。仿真结果表明,该算法在吞吐量和公平性方面都得到了较好的改善。     

LTE系统动态资源调度技术研究探讨

对LTE系统中的资源调度机制进行了研究和探讨,对三种传统的方法进行了性能比较,跨层的调度算法考虑了不同的QoS需求,建议针对特别QoS需求的场景选择不同的调度算法.文章重点介绍了自适应调制和编码技术混合自动重传请求技术,并对LTE资源调度进行了总结.     

一种基于跨层反馈信息的下行OFDMA资源分配策略

基于跨层调度的思想,本文深入研究了正交频分多址(OFDMA)系统中的资源分配问题。本文提出的调度算法联合利用了媒体访问控制(MAC)层的确认字符(ACK/NAK)信息和物理层(PHY)周期反馈的用户信噪比(SNR)信息。同时该调度问题在本文中被建模成一个带有跨层观测信息的部分观测马尔科夫决策过程(POMDP)。为了降低复杂度,本文利用了一个简化的模型,使其能够应用于实际的系统中。数学仿真显示,本文提出算法的性能十分接近Aggarwal R等人提出的理论上限,并且通过利用ACK/NAK信息大大减小了系统的反馈开销。     

3G长期演进系统无线资源下行链路调度算法初探

文章主要阐述三种经典的OFDM系统中的资源调度算法比较,同时简略介绍现阶段流行的调度算法,并指出,能更好地协调多维度的资源调度、跨层调度、包调度与其他的无线资源管理方法紧密结合的调度方法都是今后的研究方向.研究方向.     

无线系统载波聚合下资源调度研究

由于LTE系统中最大只能使用20MHZ带宽的限制,3GPP在Release10中提出使用载波聚合技术(CA),允许将多个不同频段或相同频段的载波聚合在一起,将带宽扩展。文章针对LTE-A系统载波聚合下资源调度进行研究,首先分析研究了联合载波调度和独立载波调度的优缺点,最后在搭建的LTE-A系统仿真平台上对两种算法进行验证。结果表明,采用联合载波调度比独立载波调度在提高系统平均吞吐量方面更具有优势。     

基于队列感知和信道感知的上行调度算法研究

LTE系统中,区别于下行链路资源调度,上行链路采用了单载波正交频多址(SC-FDMA)技术,这要求必须满足分配的RB资源具有连续性这一限制,增加了上行资源分配的难度。传统的分组调度算法因为这一限制,不能很好地保证频率资源的有效利用。针对此问题,文章提出了一种基于队列感知和信道感知的LTE系统上行调度算法。通过对该算法进行仿真,表明该算法提高了频谱效率,同时提高了系统的吞吐量。     

基于MAC层优先级调度的宽带电力线跨层资源分配

传统的资源分配算法采用分层系统,且不适用于宽带电力线通信系统中的不良信道环境。文中引入跨层思想提高资源利用率,保证服务质量(QoS),提出了一种基于MAC层QoS优先级调度功能的宽带电力线跨层资源分配方案。该算法考虑了实时用户对延迟的要求和非实时用户对队列长度的要求,并提出用户优先级函数。根据其优先级函数计算每个用户的数据包数量,生成基于效用函数的调度序列。在物理层中,根据调度的数据包,该算法分配物理资源用于分组。仿真结果表明,该算法在提高用户QoS的同时兼顾了系统的性能和吞吐量。     

一种适用于多用户OFDM系统下行链路的跨层设计调度算法

该文提出了一种适用于多用户正交频分复用(OFDM)系统下行链路的调度算法,基于跨层结构设计,并分别考虑了媒体接入控制(MAC)层的用户服务质量(QoS)要求、用户公平性、数据包队列状态信息以及物理层的信道状态信息(CSI)和功率约束等。多用户OFDM系统可以通过该调度算法充分利用MAC层和物理层的不同参数特性,在保证用户QoS的同时最大化频谱的利用效率。仿真结果表明,在小区内各个移动用户具有不同的接收SNR的情况下,该算法具有服务质量随信噪比波动平缓、丢包率低、实现复杂度低等特点。     

Utility-based resource allocation and scheduling in OFDM-based wireless broadband networks

This article discusses downlink resource allocation and scheduling for OFDM-based broadband wireless networks. We present a cross-layer resource management framework leveraged by utility optimization. It includes utility-based resource management and QoS architecture, resource allocation algorithms, rate-based and delay-based multichannel scheduling that exploits wireless channel and queue information, and theoretical exploration of the fundamental mechanisms in wireless resource management, such as capacity, fairness, and stability. We also provide a solution that can efficiently allocate resources for heterogeneous traffic with diverse QoS requirements.     

Max-utility subcarrier allocation for heterogeneous services in wireless OFDM system

In future wireless network, one user will require multiple homogeneous or heterogeneous services simultaneously. Then, the scheduling algorithm is not only responsible for assigning a resource block to different users but also sharing the assigned resource block among multiple services for one user. Most of the traditional scheduling algorithms are designed to serve one service per user, and cannot be applied directly to this scenario because of the fairness criterion. This article focuses on adaptive resource allocation for multiple services per user at the downlink of orthogonal frequency division multiplexing (OFDM) based system. This article addresses this integrative resource scheduling problem based on utility function. First, the optimal algorithm for dynamic subcarrier allocation and share is deduced for homogeneous best-effort service system. Then the algorithm is extended to heterogeneous services system by classifying the delay sensitive service according to the head-of-line packet delay. The design goal is to maximize aggregate utility function to exploit multiuser diversity gain to the greatest extent even as guaranteeing quality of service (QoS) for delay sensitive service.     

分组交换网络中虚拟时钟调度算法研究

基于虚拟时钟的算法在实现对资源进行公平分配的同时具备良好的可扩展性，从而能够满足QOS控制中对于分组调度算法的需求。本文主要对一些基于虚拟时钟的调度算法进行了分析和讨论，这也是进行QOS控制研究的基础。     

LTE系统上行调度算法研究

无线资源调度是LTE系统研究的一个热点问题。L11E上行链路采用了单载波正交频多址（sc—FDMA）技术,要求在调度时为任一用户分配的RB必须是连续的,使得LTE下行调度算法不能直接应用上行调度。本文对LTE系统上行链路资源调度问题的研究状况进行了概述,分别从信道感知、比例公平、QoS保证三个方面,对现有调度算法进行了分析和比较。重点分析比较了各个算法在保证分配的RB连续的前提下系统性能,并提出了进一步研究的方向。     

Traffic Aided Uplink Opportunistic Scheduling with QoS Support in Multiservice CDMA Networks

In this letter, we address the problem of resource allocation with efficiency and quality of service (QoS) support in uplink for a wireless CDMA network supporting real‐time (RT) and non‐realtime (NRT) communication services. For RT and NRT users, there are different QoS requirements. We introduce and describe a new scheme, namely, traffic aided uplink opportunistic scheduling (TAUOS). While guaranteeing the different QoS requirements, TAUOS exploits the channel condition to improve system throughput. In TAUOS, the cross‐layer information, file size information, is used to improve fairness for NRT users. Extensive simulation results show that our scheme can achieve high system throughput in uplink wireless CDMA systems, while guaranteeing QoS requirements.     

Dynamic resource scheduling schemes for W-CDMA systems

W-CDMA is the strongest candidate for the air interface technology of third-generation wireless communication systems. Dynamic resource scheduling is proposed as a framework that will provide QoS provisioning for multimedia traffic in W-CDMA systems. The DRS framework monitors the traffic variations and adjusts the transmission powers of users in an optimal manner to accommodate different service classes efficiently. Variable and optimal power allocation is suggested to provision error requirements and maximize capacity, while prioritized queuing is introduced to provision delay bounds. A family of DRS algorithms has been devised along these dimensions for obtaining different levels of QoS. The DRS schemes are discussed in terms of queuing and bandwidth allocation with an emphasis on their impact on delay QoS     

Joint Power-Frequency-Time Resource Allocation in Clustered Wireless Mesh Networks

Wireless mesh networking is an emerging technology for future broadband wireless access. Future wireless networking can benefit from a robust and reliable wireless mesh backbone rendered by mesh routers, providing an all-wireless ambience. Due to the requisite multichannel communications for high-speed data transmissions, power allocation for opportunistically exploiting fading wireless channels, and packet scheduling for QoS provisioning, joint power-frequency-time resource allocation is indispensable. In this article we propose a low-complexity intracluster resource allocation algorithm, taking power allocation, subcarrier allocation, and packet scheduling into consideration. Numerical results demonstrate that our scheme is near optimal, and that our optimality-driven resource allocation approach outperforms a greedy algorithm, working out a better performance compromise among throughput, packet dropping rate, and packet delay.     

QoS‐aware LTE‐A downlink scheduling algorithm: A case study on edge users

4G/LTE‐A (Long‐Term Evolution—Advanced) is the state of the art wireless mobile broadband technology. It allows users to take advantage of high Internet speeds. It makes use of the OFDM technology to offer high speed and provides the system resources both in time and frequency domain. A scheduling algorithm running on the base station holds the allocation of these resources. In this paper, we investigate the performance of existing downlink scheduling algorithms in two ways. First, we look at the performance of the algorithms in terms of throughput and fairness metrics. Second, we suggest a new QoS‐aware fairness criterion, which accepts that the system is fair if it can provide the users with the network traffic speeds that they demand and evaluate the performance of the algorithms according to this metric. We also propose a new QoS‐aware downlink scheduling algorithm (QuAS) according to these two metrics, which increases the QoS‐fairness and overall throughput of the edge users without causing a significant degradation in overall system throughput when compared with other schedulers in the literature.     

一种适用于W-CDMA系统的多业务无线资源调度算法

3G系统将以分组交换方式提供语音、数据、视频等具有不同QoS要求的多种业务，资源调度对保证系统服务质量和提高资源利用效率起关键作用．本文提出了一种基于业务类型、当前待发送负荷以及剩余延时限的时间调度策略和基于资源优化的资源调度策略，并使无线链路的传输质量与业务的优先级水平一致．通过系统仿真评价了算法的性能．     

Robust QoS Control for Single Carrier PMP Mode IEEE 802.16 Systems

The IEEE 802.16 WirelessMAN standard provides a comprehensive quality-of-service (QoS) control structure to enable flow isolation and service differentiation over the common wireless network interface. By specifying a particular set of service parameters, the media access control (MAC) mechanisms defined in the standard are able to offer predefined QoS provisioning on a per-connection basis. However, the design of efficient, flexible, and yet robust MAC scheduling algorithms for such QoS provisioning still remains an open topic. This paper proposes a new QoS control scheme for single-carrier point-to-multipoint mode wireless metropolitan area network (WirelessMAN) systems, which enables the predefined service parameters to control the service provided to each uplink and downlink connection. By MAC-PHY cross-layer resource allocation, the proposed scheme is robust against particular wireless link degradation. Detailed simulation experiments are presented to study the performance and to validate the effectiveness of the proposed QoS control scheme.