一种超额认购虚拟数据中心的嵌入算法

多租户数据中心环境下,保证云应用性能的一个重要因素是为租户应用提供可保证的通信带宽,这可以通过为每个租户提供一个独占的虚拟数据中心(VDC)来实现.研究了在物理数据中心网络中超额认购数据中心的嵌入问题.相对于一般虚拟数据中心,超额认购虚拟数据中虚拟机之间的流量模式更加复杂,因此首先利用线性规划方程阐述了流量模型及嵌入问题.对于虚拟机嵌入问题,提出了一种具有较低时间复杂度的启发式算法——分组扰动算法.最后,通过仿真实验将分组扰动算法和先前工作中提出的算法以及著名的first-fit进行了比较,实验表明所提算法在降低算法复杂度的同时提高了嵌入成功率.     

基于时序差分的动态信道分配算法

合理的信道分配可以提高移动蜂窝网络的服务质量，用户高速移动以及流量突增等应用场景给移动蜂窝网络信道分配技术带来了挑战，动态信道分配算法成为当前研究的热点。基于此，首先引入用户呼叫的移动模型及其相关定义；其次建立了移动蜂窝网络信道分配环境的马尔可夫模型，使用时序差分对问题模型求解；最后通过搭建移动蜂窝网络信道分配仿真平台，在小区均匀流量和不均匀流量分布场景下对不同信道分配算法进行仿真实验。结果表明，所提算法大大降低了切换呼叫阻塞率，满足高移动高流量通信场景下的用户需求。     

一种基于动态配额的虚拟网带宽公平调度算法

网络虚拟化被广泛用于网络实验平台和数据中心等场景中。作为虚拟化网络中的核心组网设备,虚拟路由器可以在同一物理底层上构建多个虚拟路由器实例来承载多个虚拟网。其核心调度问题在于如何根据不同虚拟网对带宽的不同需求,将网络数据包调度到不同的实例中。该文针对该问题对虚拟化场景下的队列调度问题进行建模,提出了基于动态配额的队列调度算法,与miDRR等算法相比,该文算法在虚拟网带宽分配的有效性和公平性上有明显优势。     

感知无线电中频谱共享技术的研究

文章研究了感知无线电网络中联合频谱分配和调度的问题,给出了基于物理干扰模型的频谱分配算法。调度算法是对由频谱分配算法得到的一系列传输模式进行调度,从而实现频谱共享。本文基于提出的频谱分配算法通过仿真比较了三种调度算法,结果表明考虑了公平性的调度算法的网络吞吐量有稍微的降低（可达到最大吞吐量的96%）,但感知用户的整体需求满足度却得到了很大的提高,即达到了很好的公平性。     

对数比例公平队列:一种新的调度算法

Internet路由器中的队列调度算法关系到用户数据流能够获得的服务质量以及整个网络的性能,该文提出了一种新的队列调度算法对数比例公平队列调度算法,并通过理论分析和仿真说明了该队列调度算法的一些特性,这种算法不仅实现了网络总效用、网络传输性能与资源分配公平性的折衷,还具有对恶意用户的惩罚作用,鼓励用户使用合理的端到端流量控制算法。     

基于非正交多址接入的网络切片联合用户关联和功率分配算法

为了满足网络切片多样化需求,实现无线虚拟资源的动态分配,该文提出在C-RAN架构中基于非正交多址接入的联合用户关联和功率资源分配算法。首先,该算法考虑在不完美信道条件下,以切片和用户最小速率需求及时延QoS要求、系统中断概率、前传容量为约束,建立在C-RAN场景中最大化长时平均网络切片总吞吐量的联合用户关联和功率分配模型。其次,将概率混合优化问题转换为非概率优化问题,并利用Lyapunov优化理论设计一种基于当前时隙的联合用户调度和功率分配的算法。最后采用贪婪算法求得用户关联问题次优解;基于用户关联的策略,将功率分配的问题利用连续凸逼近方法将其转换为凸优化问题并采用拉格朗日对偶分解方法获得功率分配策略。仿真结果表明,该算法能满足各网络切片和用户需求的同时有效提升系统时间平均切片总吞吐量。     

基于能效的NOMA蜂窝车联网动态资源分配算法

在支持车与车直接通信(V2V)的非正交多址接入(NOMA)蜂窝网络场景下,针对V2V用户与蜂窝用户的干扰以及NOMA准则下的功率分配问题,该文提出一种基于能效的动态资源分配算法。该算法首先为了保证V2V用户的时延及可靠性同时满足蜂窝用户的速率需求,联合考虑子信道调度、功率分配和拥塞控制,建立了最大化系统能效的随机优化模型。其次,利用李雅普诺夫随机优化方法,通过控制可接入数据量保证队列稳定性以避免网络拥塞,并根据实时网络负载状态动态地进行资源调度,设计一种次优化子信道匹配算法获得用户调度方案,进一步,利用凸优化理论和拉格朗日对偶分解方法得到功率分配策略。最后,仿真结果表明,该文算法可以满足不同用户的服务质量(QoS)需求,并在保证网络稳定性前提下提高系统能效。     

无线虚拟网络中基于自回归滑动平均预测的在线自适应虚拟资源分配算法

该文针对无线虚拟化网络中业务的不确定和信息反馈的时延而引起虚拟资源分配不合理,提出一种基于自回归滑动平均(ARMA)预测的在线自适应虚拟资源分配算法。首先,该算法以保障虚拟网络队列上溢概率为目标对时频资源和缓存资源进行联合分配,并建立虚拟网络总成本最小化的理论分析模型。其次,考虑到虚拟网络对不同资源差异化的应用需求,设计了一种多时间尺度的资源动态调度机制,在长周期上基于ARMA模型的预测信息实现缓存资源的预留策略,在短周期上基于利用大偏差原理推导的队列上溢概率对虚拟网络优先级排序,并根据确定的优先级动态调度时频资源,从而满足各虚拟网络的业务需求。仿真结果表明,该算法可有效降低比特丢失率,同时提升物理资源的利用率。     

多输出队列网络的轮询权重自适应调度算法

队列调度对于网络QoS至关重要。常见的多队列轮询调度算法对不同的输出队列设置不同的固定权值,这类算法在一定程度上能改善队列调度的公平性,但对于网络数据类型和流量变化较大的场合适应性较差。本文提出一种队列轮询权重自适应的方法,能较好的满足不同类型数据分组的QoS需求。     

具有服务质量(QoS)保障的调度算法研究

目前网络用户非常关心其所上缴的费用是否能对应自己获得的性能服务。在交换节点处实施的调度算法是解决这个问题的重要手段之一。现实的网络背景环境决定了在核心网节点处的调度算法需满足数据流数目多、流量大的要求,而且应使得用户上缴费用与其所获得的服务性能大致成线性关系。根据这个重要的思想对交换节点处的调度算法进行研究设计以及进行初步的仿真验证。     

虚拟两天线蜂窝网络中考虑中继公平性的协作博弈调度方法(英文)

In thsssse cellular network, Relay Stations (RSs) help to improve the system performance; however, little work has been done considering the fairness of RSs. In this paper, we study the cooperative game approaches for scheduling in the wireless relay networks with two-virtual-antenna array mode. After defining the metric of relay channel capacity, we form a cooperative game for scheduling and present the interpretation of three different utilization objectives physically and mathematically. Then, a Nash Bargaining Solution (NBS) is utilized for resource allocation considering the traffic load fairness for relays. After proving the existence and uniqueness of NBS in Cooperative Game (CG-NBS), we are able to resolve the resource allocation problem in the cellular relay network by the relay selection and subcarrier assignment policy and the power allocation algorithm for both RSs and UEs. Simulation results reveal that the proposed CG-NBS scheme achieves better tradeoff between relay fairness and system throughput than the conventional Maximal Rate Optimization and Maximal Minimal Fairness methods.     

基于多门限预留机制的自适应带宽分配算法

针对异构无线网络融合环境提出了一种基于多门限预留机制的自适应带宽分配算法,从而为多业务提供QoS保证。该算法采用多宿主传输机制,通过预设各个网络中不同业务的带宽分配门限,并基于各个网络中不同业务和用户的带宽分配矩阵,根据业务k支持的传输速率等级需求和网络状态的变化,将自适应带宽分配问题转化为一个动态优化问题并采用迭代方法来求解,在得到各个网络中不同业务和用户优化的带宽分配矩阵的同时,在带宽预留门限和网络容量的约束条件下实现网络实时吞吐量的最大化,以提高整个异构网络带宽的利用效率。数值仿真结果显示,所提算法能够支持满足QoS需求的传输速率等级,减小了新用户接入异构网络的阻塞概率,提高了平均用户接入率并将网络吞吐量最大提高40%。     

An elastic resource allocation algorithm enabling wireless network virtualization

Following the wired network virtualization, virtualization of wireless networks becomes the next step aiming to provide network or infrastructure providers with the ability to manage and control their networks in a more dynamic fashion. The benefit of the wireless mobile network virtualization is a more agile business model where virtual mobile network operators (MNOs) can request and thus pay physical MNOs in a more pay‐as‐you‐use manner. This paper presents some resource allocation algorithms for joint network virtualization and resource allocation of wireless networks. The overall algorithm involves the following two major processes: firstly, to virtualize a physical wireless network into multiple slices, each representing a virtual network, and secondly, to carry out physical resource allocation within each virtual network (or slice). In particular, the paper adopts orthogonal frequency division multiplexing (OFDM) as its physical layer to achieve more efficient resource utilization. Therefore, the resource allocation is conducted in terms of sub‐carriers. Although the motivation and algorithm design are based on IEEE 802.16 or WiMAX networks, the principle and algorithmic essence are also applicable to other OFDM access‐based wireless networks. The aim was to achieve the following design goals: virtual network isolation and resource efficiency. The latter is measured in terms of network throughput and packet delivery ratio. The simulation results show that the aforementioned goals have been achieved. Copyright © 2012 John Wiley & Sons, Ltd.     

Utility optimization scheduling for multi-point video surveillance in ubiquitous network

Resource allocation is an important problem in ubiquitous network. Most of the existing resource allocation methods considering only wireless networks are not suitable for the ubiquitous network environment, and they will harm the interest of individual users with instable resource requirements. This paper considers the multi-point video surveillance scenarios in a complex network environment with both wired and wireless networks. We introduce the utility estimated by the total costs of an individual network user. The problem is studied through mathematical modeling and we propose an improved problem-specific branch-and-cut algorithm to solve it. The algorithm follows the divide-and-conquer principle and fully considers the duality feature of network selection. The experiment is conducted by simulation through C and Lingo. And it shows that compared with a centralized random allocation scheme and a cost greed allocation scheme, the proposed scheme has better per- formance of reducing the total costs by 13.0% and 30.6% respectively for the user.     

基于在线双向拍卖的虚拟网络切片资源调度机制

为解决 5G网络切片间资源分配的问题,该文提出一种基于在线双向拍卖 (ODA)的资源调度机制。该机制首先针对不同的业务需求和业务收益确定网络切片的优先级和单位资源报价;其次明确最大化网络收益的目标建立线下单向拍卖模型;进一步,考虑资源的动态分配和回收利用,提出价格更新算法实时更新资源价格;最后,综合线下单向拍卖机制和价格动态变化机制建立在线双向拍卖模型,为切片动态分配资源。仿真结果表明,该机制在提高网络收益的同时可以保证各切片用户的QoS需求。     

An optimal solution to resource allocation among soft QoS traffic in wireless network

Optimization theory and nonlinear programming method have successfully been applied into wire‐lined networks (e.g., the Internet) in developing efficient resource allocation and congestion control schemes. The resource (e.g., bandwidth) allocation in a communication network has been modeled into an optimization problem: the objective is to maximize the source aggregate utility subject to the network resource constraint. However, for wireless networks, how to allocate the resource among the soft quality of service (QoS) traffic remains an important design challenge. Mathematically, the most difficult comes from the non‐concave utility function of soft QoS traffic in the network utility maximization (NUM) problem. Previous result on this problem has only been able to find its sub‐optimal solution. Facing this challenge, this paper establishes some key theorems to find the optimal solution and then present a complete algorithm called utility‐based allocation for soft QoS to obtain the desired optimal solution. The proposed theorems and algorithm act as designing guidelines for resource allocation of soft QoS traffic in a wireless network, which take into account the total available resource of network, the users’ traffic characteristics, and the users’ channel qualities. By numerical examples, we illustrate the explicit solution procedures.Copyright © 2013 John Wiley & Sons, Ltd.     

Resource allocation for real-time traffic in unreliable wireless cellular networks

Providing reliable transmission for real-time traffic in wireless cellular networks is a great challenge due to the unreliable wireless links. This paper concentrates on the resource allocation problem aiming to improve the real-time throughput. First, the resource allocation problem is formulated as a Markov Decision Process and thus the optimal resource allocation policy could be obtained by adopting the value iteration algorithm. Considering the high time complexity of the optimal algorithm, we further propose an approximate algorithm which decomposes the resource allocation problem into two subproblems, namely link scheduling problem and packet scheduling problem. By this method, the unreliable wireless links are only constrained in the link scheduling problem, and we can focus on the real-time requirement of traffic in packet scheduling problem. For the link scheduling problem, we propose the maxRel algorithm to maximize the long-term network reliability, and we theoretically prove that the maxRel algorithm is optimal in scenarios with dynamic link reliabilities. The Least Laxity First algorithm is adopted for the packet scheduling problem. Extensive simulation results show that the proposed approximate resource allocation algorithm makes remarkable improvement in terms of time complexity, packet loss rate and delay.     

Adaptive envelope process and minimum service curve applied to resource block allocation in the LTE downlink

In this work, we propose a resource allocation algorithm for the LTE downlink that makes use of an adaptive multifractal envelope process and a minimum service curve. The proposed scheduling algorithm aims to improve some network parameters while guaranteeing a maximum delay to the user by considering the following information: backlog, channel condition and user traffic behavior. In order to estimate the maximum network delay, we propose an adaptive minimum service curve for the LTE network that can be used for admission control purposes in the resource allocation algorithm. The performance of the proposed scheduling algorithm is compared to those of several scheduling schemes known in the literature through computational simulations of the LTE downlink. In order to develop a new adaptive envelope process and to precisely describe network flows, we propose an adaptive algorithm to estimate the parameters of the Multifractal Wavelet Model (MWM). The proposed envelope process is compared to the main traffic model based envelope processes known in the literature. Simulations of the LTE downlink considering AMC (Adaptive Modulation and Coding) are carried out showing the efficiency of the proposed resource allocation approach that considers adaptive estimation of network traffic parameters.     

Virtual channel load-balanced routing algorithm for Torus networks

In order to improve the network performance furthermore,a routing algorithm for 2D-Torus is investigated from the standpoint of load balance for virtual channels.The 2D-Torus network is divided into two virtual networks and each physical channel is split into three virtual channels.A novel virtual channel allocation policy and a routing algorithm are proposed,in which traffic load is distributed to those three virtual channels in a more load-balanced manner by introducing a random parameter.Simulations of the proposed algorithm are developed with a SystemC-based test bench.The results show that compared with the negative first for Torus networks(NF-T) algorithm,the proposed algorithm can achieve better performance in terms of network latency and throughput under different traffic patterns.It also shows that a routing algorithm with load balance for virtual channels can significantly improve the network performance furthermore.