多用户正交频分复用加权比例公平调度

传统的正交频分复用(OFDM)调度进行资源分配时没有考虑用户间速率比例公平性。针对这一问题,提出了一种新的适合于混合业务的多用户OFDM系统比例公平调度方案,其用户队列承载混合类型业务。该方案在用户间速率成比例约束条件下最大化系统权重容量和;授予用户队列中不同类型的分组不同的权重因子,并通过权重因子计算用户的权重;在子载波分配时不仅定义了信道优先级因子,而且在用户间速率成比例公平约束条件下通过该因子为用户分配子载波;最后推导出一种线性的功率分配方式。仿真结果与分析显示,该方案可以较好地满足用户速率和业务时延的需求,且可以在有效提高系统容量的基础上,严格地保证用户容量公平性。     

基于公平性的OFDMA系统中自适应功率分配贪婪算法

功率分配是OFDMA系统资源调度中的一个重要研究问题。该文通过考虑功率分配中系统吞吐量与用户间公平性能平衡问题,提出了一种公平约束下的功率分配贪婪算法。将算法与经典算法比较,在使用户公平性大为提高的同时,使OFDM系统达到最大吞吐量。仿真结果表明,该算法的吞吐量逼近迭代注水功率分配算法。     

小无线网络中基于BLUF的包调度算法

在无线网络的多用户资源分配中,一个重要的问题就是设计高效的调度算法来保证用户的公平性,并充分利用有限资源和保证用户服务质量要求。提出一种基于缓冲区长度效用函数的多用户包调度（BLUF）算法,该算法充分考虑无线信道的时变特性,用缓冲区长度的效用函数来表示调度的服务质量需求的紧急程度,用户当前信道速率与其获得的平均信道速率的比值表示用户公平性和系统效率的权衡程度。仿真结果表明,与存在的比例公平性无线包调度（PFS）算法相比,BLUF算法能够保证实时任务的时延需求的前提下,获得更好的公平性、系统吞吐量等性能。     

Efficiency-aware and fairness-aware joint-layer optimization for downlink data scheduling in OFDM

Efficiency and fairness are two crucial issues to be considered for resource alloca- tion in multi-user wireless networks. Based on the joint optimization of physical layer and data link layer, an optimization model is derived to achieve efficient and fair downlink data scheduling in multi-user OFDM wireless networks by maximizing the total utility function with respect to the average waiting time of user queue. A dynamic sub-carrier allocation algorithm （DSAA） based on the optimization model is proposed in order to obtain the maximization of the total scheduling utility. Effi- ciency is improved by combining DSAA with time scale interference predictor （TSIP） which at large time scales predict ON/OFF period of user data with temporal corre- lation structure across multiple time scales in multi-user interference environment. Simulation results verify the efficiency and fairness of the scheme.     

Cross-layer packet scheduling for downlink multiuser OFDM systems

This paper proposes a channel and queue aware fair (CQAF) packet scheduling scheme for the downlink packet transmission in multiuser orthogonal frequency division multiplexing (OFDM) systems. By making use of the information on the channel conditions and the queue lengths, the proposed CQAF packet scheduling scheme efficiently allocates the subcarriers, transmission power and modulation level to users under the constraints of total transmission power, the number of subcarriers, bit-error-rate (BER) requirement and generalized processor sharing (GPS)-based fairness requirement. The numerical results show that the proposed CQAF packet scheduling scheme can reduce the transmission delay and queue length significantly while maximizing system throughput and maintaining fairness among users.     

基于跨层的中高速传感器网络多元参数调度与资源自适应分配算法

针对中高速传感器网络中不同业务对QoS(quality of scrvice)的不同要求,跨层考虑物理层和数据链路层参数,提出了一种适合混合业务的多元参数调度算法和资源分配算法。该算法根据不同的业务动态调整时延补偿因子和吞吐量补偿因子两个参数,在满足实时业务QoS约束的前提下,以最大化系统吞吐量为目标建立了相应的优化模模型,对于实时业务能满足时延较小的要求,对于非实时业务能满足吞吐量较大的要求。仿真结果表明,该调度算法可以灵活地在系统功率效率和用户服务质量满意度之间取得折衷,并保证不同类型业务用户间的公平性。     

无线MIMO系统的上行资源分配算法研究

在存在同信道干扰的无线MIMO系统中,为具有多种QoS需求的调度业务分配资源是一个具有挑战性的问题.提出一种实用的、基于SDMA的贪婪资源分配(SGRA)算法.在高效的干扰管理基础上,SGRA算法可以执行两阶段启发式计算和搜索.在第1阶段,包括上行调度和子信道分配的贪婪资源分配首先在时域频域二维进行;在第2阶段,资源分配被扩展到时域频域空域三维进行.SGRA的算法复杂度低,适用于实际无线通信系统.仿真结果表明,与同类算法相比,SGRA算法可以提高系统吞吐量,更好地保证实时业务的时延和最小数据速率需求,同时兼顾系统公平性.     

Joint spectrum allocation and scheduling for fair spectrum sharing in cognitive radio wireless networks

Cognitive radio and Dynamic Spectrum Access (DSA) enable wireless users to share a wide range of available spectrums. In this paper, we study joint spectrum allocation and scheduling problems in cognitive radio wireless networks with the objectives of achieving fair spectrum sharing. A novel Multi-Channel Contention Graph (MCCG) is proposed to characterize the impact of interference under the protocol model in such networks. Based on the MCCG, we present an optimal algorithm to compute maximum throughput solutions. As simply maximizing throughput may result in a severe bias on resource allocation, we take fairness into consideration by presenting optimal algorithms as well as fast heuristics to compute fair solutions based on a simplified max–min fairness model and the well-known proportional fairness model. Numerical results show that the performance given by our heuristic algorithms is very close to that of the optimal solution, and our proportional fair algorithms achieve a good tradeoff between throughput and fairness. In addition, we extend our research to the physical interference model, and propose effective heuristics for solving the corresponding problems.     

A cross-layer resource allocation scheme for ICIC in LTE-Advanced

As a new technology, inter-eNB coordination has been included in LTE-Advanced study items. Moreover, the network architecture in LTE-Advanced system is modified to take into account coordinated transmission. In our study, we explore the problem of jointly optimizing the power level and scheduling of resource blocks for LTE-Advanced network based on orthogonal frequency division multiplexing (OFDM). We propose a distributed optimization scheme based on evolutionary potential games, and in the process of objective function modeling we employ the Lagrangian multiplier method to solve the constraint objective optimization problem. Then particle swarm optimization (PSO) method is adopted to find the optimal power allocation and scheduling for each resource block in the multi-cell framework. Numerical results prove that proposed algorithm notably improves the overall throughput, while user fairness is guaranteed. Importantly, additional computation and communication cost introduced by cross-layer optimization is also evaluated.     

认知OFDM无线电系统基于公平度门限的资源分配

根据认知无线电的特点和正交频分复用(OFDM)的传输特性,提出了一种针对认知OFDM无线电系统的自适应资源分配算法。在传统的子载波分配过程中,具有优先权的用户将优先选择载波,但信道增益最大的载波并不一定会被其使用,这将导致载波利用效率下降。针对这一问题,该算法在载波分配过程中,通过公平度门限来决定载波分配的优先级,从而实现容量和公平度的折中。同时,在子载波和功率分配中使次用户对主用户的干扰功率限制在主用户可容忍的干扰极限内,保证了每个用户的通信要求。仿真结果表明,该算法在满足公平性的同时还提升了系统的容量。     

分布式系统中的多用户并行调度算法

针对传统调度算法的不足,在多用户分布式天线系统的下行链路中引入并行调度思想,从而在系统吞吐量和公平性能间取得折中。首先将轮询调度算法进行了改进,同时提出一种并行调度算法,每次选择瞬时数据率和平均吞吐量较高的多个用户进行通信。采用优化的匹配算法改进传统穷尽搜索计算量大的缺陷。仿真结果显示与传统的并行调度和改进的并行轮询调度相比,本文算法在保证吞吐量的情况下,公平性有了显著提高。     

基于烟花算法的D2D资源分配方案

D2D（Device-to-Device）通信通过复用蜂窝用户的频谱资源来提升系统频谱资源的利用率，并提高系统吞吐量，但同时也为系统带来了严重的同频干扰。为了应对复杂的干扰问题，并在保证资源分配公平性的情况下尽可能提高系统吞吐量，提出一种基于烟花算法的D2D资源分配方案，以最大化系统的加权和速率为目标，将资源分配矩阵抽象为烟花，通过爆炸、变异、选择等过程求出最终的匹配矩阵。仿真结果表明，所提方案能够有效提高系统的吞吐量和资源分配的公平性。     

一种基于认知无线电系统的公平信道分配算法*

由于在认知无线电网络中主用户与认知用户共存,如何在不对主用户造成干扰的前提下.对认知用户进行合理的资源分配显得尤为重要.以纳什协调解为优化目标,并考虑功率约束,提出一种公平信道分配算法.在仿真中,对以吞吐量最大化为目标的Maximal-Rate策略和考虑公平的Max-Min策略进行了对比,仿真结果表明.本算法有着与Ma...     

Subcarrier allocation in multi-hop orthogonal frequency division multiple access wireless networks

Orthogonal frequency division multiplexing (OFDM) has been widely considered as a key technique for next generation mobile communication systems. Meanwhile, relaying technologies can improve users’ quality of service, increase network capacity and enlarge cellular coverage at a low cost. In this paper, we focus on subcarrier allocation and utilization in multi-hop OFDM access (OFDMA) wireless networks, and propose two efficient subcarrier allocation schemes aiming to increase network throughput and subcarrier utilization. The first scheme selects suitable links for data transmission from base stations to terminals at the beginning. Then, interference-free links are included into the same group for network resource reuse. For the purpose of global optimization, we propose a Tabu-based searching algorithm as the second subcarrier allocation scheme. Simulation results demonstrate that our proposed algorithms outperform other schemes in both network throughput and subcarrier utilization.     

Joint routing, scheduling, and power control for multichannel wireless sensor networks with physical interference

Reliability and real-time requirements bring new challenges to the energy-constrained wireless sensor networks, especially to the industrial wireless sensor networks. Meanwhile, the capacity of wireless sensor networks can be substantially increased by operating on multiple nonoverlapping channels. In this context, new routing, scheduling, and power control algorithms are required to achieve reliable and real-time communications and to fully utilize the increased bandwidth in multichannel wireless sensor networks. In this paper, we develop a distributed and online algorithm that jointly solves multipath routing, link scheduling, and power control problem, which can adapt automatically to the changes in the network topology and offered load. We particularly focus on finding the resource allocation that realizes trade-off among energy consumption, end-to-end delay, and network throughput for multichannel networks with physical interference model. Our algorithm jointly considers 1) delay and energy-aware power control for optimal transmission radius and rate with physical interference model, 2) throughput efficient multipath routing based on the given optimal transmission rate between the given source-destination pairs, and 3) reliable-aware and throughput efficient multichannel maximal link scheduling for time slots and channels based on the designated paths, and the new physical interference model that is updated by the optimal transmission radius. By proving and simulation, we show that our algorithm is provably efficient compared with the optimal centralized and offline algorithm and other comparable algorithms.     

一种公平的认知无线电系统下行频谱分配策略

目前关于认知无线电频谱分配的研究大多以最大化系统容量为目标,很少考虑认知用户的QoS需求,频谱分配方案设计缺乏公平性。针对主用户干扰限制和保障认知用户QoS需求,结合OFDM技术,研究了认知无线电场景中下行多用户分配算法。该算法构建不等式约束下的目标函数以最大化系统容量,通过拉格朗日(Lagrange)对偶优化法给出近似最优解。仿真结果表明,所提算法在牺牲系统和容量的前提下充分保证了次用户的QoS需求,提高了系统的公平性。     

基于效用的超宽带系统带宽分配

把超宽带系统的带宽优化调度表示为一个效用最大化的问题。对于系统的带宽分配,效用函数是服务质量的有效度量,它反映了用户对所分配的资源的满意程度。针对超宽带无线网络带宽分配中链路和用户的集中式算法的复杂性,用分布式方案解决这种问题,以自适应变化的无线网络环境。对系统带宽进行基于效用的分配,满足超宽带系统高速率传输的需要。     

一种自适应跨层空间子信道分配算法——基于多用户MIMO／OFDM系统

MIMO／OFDM是未来宽带无线通信接口的有效架构。本文提出了一种自适应跨层空间子信道分配算法，在多用户MIMO／OFDM系统中，联合链路层截短ARQ（T-ARQ）技术，以获取物理层最大的系统吞吐量为目标，推导了子载波分配准则，并给出了相应的算法流程。仿真结果表明，该算法具有良好的性能，有效地提高了系统的传输速率。     

一种空间子信道分配算法及其分块设计——基于多用户MIMO/OFDM系统

MIMO-OFDM是未来宽带无线通信接口的有效架构.本文提出了一种基于多用户MIMO-OFDM系统的空间子信道分配算法,以获取最大的系统吞吐量为目标,推导了子载波分配准则,给出了相应的算法流程;为了减小计算量,本文进一步提出了基于时频块的简化设计.仿真结果表明,该算法具有良好的性能,有效地提高了系统的传输速率.     

An efficient bandwidth allocation algorithm for real-time VBR stream transmission under IEEE 802.16 wireless networks

This paper investigates variable rate control strategies for real-time multimedia variable bit rate (VBR) services over IEEE 802.16 broadband wireless networks. A data rate control mechanism is derived for the case where the uplink channel provides real-time services and the traffic rate parameter remains constant. This paper shows that the common queuing scheduling algorithms have some bandwidth allocation fairness problems for the real-time polling service (rtPS) in the MAC layer. In other words, the use of a VBR for the rtPS by a WiMAX system results in additional access latency jitter and bandwidth allocation disorder in the transmitted multimedia streams during the regular time interval polling of subscribe stations (SSs) for the contention bandwidth request period. However, the proposed scheduling algorithm solves these SSs contending with bandwidth resource allocation problems based on an extended rtPS (ertPS) of quality-of-service (QoS) pre-programming for a ranging response non-contention polling period. The adopted bandwidth allocation of max–min fairness queue scheduling uses a time constraint condition to transmit real-time multimedia VBR streaming in an IEEE 802.16 broadband wireless environment. In addition, we use the ns-2 simulation tool to compare the capacity of multimedia VBR stream and show that the proposed ertPS scheduling algorithm outperforms other rtPS scheduling algorithms.