EDCA机制下实时业务多跳传输仿真分析

在AdHoc无线自组织多跳网络中,IEEE802.11e协议采用了增强型分布信道接入机制,用于为实时多媒体业务提供有效的QoS保证机制。简单介绍和对比了802.11分布式协调功能和802.11e增强型分布信道接入机制两种信道接入机制,并通过使用网络仿真软件OPNET,模拟了实时的视、音频业务在802.11分布信道接入机制和802.11e增强型分布信道接入机制信道接入机制下在不同网络负载下的性能并进行了仿真分析。     

面向用户体验的多小区混合非正交多址接入网络资源分配方法

该文研究了多小区混合非正交多址接入(MC-hybrid NOMA)网络的资源分配.为满足异构用户的服务体验,以最大化全网综合平均意见评分(MOS)累加和为目标,考虑基站选择、信道接入和功率资源分配的联合优化问题,该文提出一种用户、基站和信道3方的2阶段转移匹配算法,并根据用户MOS进行子信道功率优化.仿真结果表明所提多小区混合NOMA网络资源分配方案能有效提升全网用户服务体验和公平性.     

基于GSIC的上行链路毫米波大规模MIMO-NOMA系统低功耗传输方法

非正交多址接入（non-orthogonal multiple access,NOMA）和毫米波大规模多输入多输出（multiple-input multiple-output,MIMO）的结合能够支持未来无线通信网络的巨流量大连接需求。研究了上行链路毫米波大规模MIMO-NOMA系统中的功率最小化问题，提出了基于群体串行干扰消除（group-levelsuccessiveinterference cancellation,GSIC）的混合波束成形毫米波MIMO-NOMA上行传输系统新架构。具体来说，根据信道增益对用户进行群体划分，不同群体用户由NOMA服务，群体内用户采用空分多址区分。通过给不同群体设计模拟波束成形矩阵，对数字波束成形和功率控制进行联合优化，提出了一种并行迭代算法来解决优化问题。仿真结果表明，所提出的新架构在总功率方面优于传统的基于分簇和用户级串行干扰消除的毫米波大规模MIMO-NOMA。     

联合网络容量与认知用户满意度的资源分配优化方案

机会频谱接入技术是提高频谱利用率的一种有效方法,论文综合考虑信道的时变性、子信道空闲的检测可信度、认知网络与主网络间的互干扰等因素,建立了一种最大化认知网络有效容量和认知用户满意度的多目标优化模型,提出了一种联合资源分配和用户调度的PAUS算法.仿真结果表明,在主用户分布密度较低的环境中,该模型较最大化网络有效容量模型具有更高的用户满意度;较最大化认知用户满意度模型可获得更高的网络有效容量.     

面向用户体验的多小区混合非正交多址接入网络资源分配方法

该文研究了多小区混合非正交多址接入(MC-hybrid NOMA)网络的资源分配。为满足异构用户的服务体验,以最大化全网综合平均意见评分(MOS)累加和为目标,考虑基站选择、信道接入和功率资源分配的联合优化问题,该文提出一种用户、基站和信道3方的2阶段转移匹配算法,并根据用户MOS进行子信道功率优化。仿真结果表明所提多小区混合NOMA网络资源分配方案能有效提升全网用户服务体验和公平性。     

基于多主用户活跃性的多功率认知接入策略

针对大多数认知无线电场景中存在多个主用户,且具有较强活跃性的问题,提出了一种基于授权用户活跃性的多主用户多状态认知接入机制以及对应的多功率接入策略。该方法能够使认知用户选择最优的授权信道接入,并采用合适的功率进行传输,实现了认知系统吞吐量的最大化。数值仿真结果表明,该接入机制能够使认知用户充分利用多主用户信息和资源。与传统的功率接入方式相比,既能减小对主用户的干扰,又能提升认知系统的容量。     

5G建网初期SSB波束设置策略

5G网络由于其自身特性及所分配频率,网络规划优化的重点是提升水平和垂直覆盖,SSB广播波束与赋形增益特性则是网络覆盖改善的技术关键点.通过研究5GNR网络SSB广播波束配置对于覆盖范围和接入性能的影响,结合仿真与测试结果分析了不同SSB广播信道波束配置的差异对比,最后针对立体覆盖场景,提出了采用水平多波束与垂直多层波束...     

多速率认知网络中协作资源共享机制研究

针对多速率认知网络分析了不同体制网络间相互协作的动机及策略.基于排队论模型,提出了不同协作策略的时延分析模型,得到了不同类型用户的业务到达率、分组长度、信道传输速率与业务平均服务时间之间的解析关系,进而揭示了不同协作资源共享机制的时延性能以及适用的场景.数值仿真验证了分析模型的准确性和有效性,同时证明:通过合理利用用户间的协作,不仅可以更好地保障主用户业务的QoS性能,还可以有效提升次级用户的接入机会和QoS保障能力.     

基于空间波束不变性的升空平台大规模MIMO导频攻击检测与消除方法

针对升空通信平台大规模多输入多输出（Multiple-Input Multiple-Output,MIMO）系统中在通信接入阶段遭受导频攻击引入的信息泄露问题,提出了一种基于空间波束不变性的导频接入攻击检测与消除方法。该方案基于用户空间波束域信道结构特征,在缺少信道先验信息的条件下使用点排序簇结构（Ordering Points to Identify the Clustering Structure,OPTICS）聚类算法,分离提取接入攻击与合法用户的波束域信道,消除接入攻击导致的信号损伤,实现合法用户信号安全传输。仿真结果表明,所提方案能够有效降低导频接入攻击对系统安全传输的影响。     

可见光通信异构网络频谱资源分配算法研究

由于当前已有方法未能对用户需求进行分析,导致可见光通信异构网络系统吞吐量以及平均满意度下降。为此,提出一种可见光通信异构网络频谱资源分配算法。将可见光通信异构网络系统最大容量作为目标,综合考虑用户需求以及最大功率限制等约束,构建可见光通信异构网络频谱资源分配模型。将模型中的对偶问题分解为简单的子问题,通过定向变异的遗传算法进行信道分配,采用拍卖算法进行信道内功率分配,最终实现网络频谱资源分配。实验结果表明,所提算法可以有效提升可见光通信异构网络系统吞吐量以及平均满意度。     

Caching resource management of mobile edge network based on Stackelberg game

Mobile edge caching technology is gaining more and more attention because it can effectively improve the Quality of Experience (QoE) of users and reduce backhaul burden. This paper aims to improve the utility of mobile edge caching technology from the perspectie of caching resource management by examining a network composed of one operator, multiple users and Content Providers (CPs). The caching resource management model is constructed on the premise of fully considering the QoE of users and the servicing capability of the Base Station (BS). In order to create the best caching resource allocation scheme, the original problem is transformed into a multi-leader multi-follower Stackelberg game model through the analysis of the system model. The strategy combinations and the utility functions of players are analyzed. The existence and uniqueness of the Nash Equilibrium (NE) solution are also analyzed and proved. The optimal strategy combinations and the best responses are deduced in detail. Simulation results and analysis show that the proposed model and algorithm can achieve the optimal allocation of caching resource and improve the QoE of users.     

Proportional bandwidth allocation with consideration of delay constraint over IEEE 802.11e-based wireless mesh networks

Wireless mesh networks (WMNs) extend the limited transmission coverage of wireless LANs by enabling users to connect to the Internet via a multi-hop relay service provided by wireless mesh routers. In such networks the quality of experience (QoE) depends on both the user location relative to the Internet gateway and the traffic load. Various channel access or queue management schemes have been proposed for achieving throughput fairness among WMN users. However, delay and bandwidth utilization efficiency of such schemes may be unacceptable for real-time applications. Accordingly, the present study proposes a proportional bandwidth allocation scheme with a delay constraint consideration for enhancing the QoE of users of WMNs based on the IEEE 802.11e standard. An analytical model of the proposed scheme is provided. Moreover, the performance of the proposed scheme is systematically compared with that of existing bandwidth allocation methods. The simulation results show that the proposed scheme outperforms previously proposed schemes in terms of both an improved throughput fairness among the WMN users and a smaller end-to-end transmission delay.     

Enhanced calculation of necessary QoS for user satisfaction with a QoS mapping matrix

The final goal of quality of service(QoS) guarantees is to assure high quality of experience(QoE) for users.We cannot control QoE,but it is feasible to use QoS control schemes at lower levels to keep QoE high.We need to know the necessary QoS parameters values which need the minimum cost but could satisfy required QoE.An enhanced method is proposed to get the necessary QoS parameters which cost minimum but could satisfy required QoE well.It abstracts the problem of obtain necessary QoS parameters to be how to get the solution of linear regression equations considering cost coefficient.The method establishes equations utilizing principal component analysis and multiple regression analysis based on normalized data.This paper defines the cost of necessary QoS and introduces the calculation of minimum cost necessary QoS parameter by inverse or generalized inverse matrix operations.The numerical example proves the normalization to be effective and the calculated values are feasible.     

Research on improving the QoE of relay users in cooperative communication systems

Customers'satisfaction with services is reflected by quality of experience (QoE). Insofar, most studies on cooperative communication have been focused on improving the QoE of source users. However, the improvement of a source user's QoE is obtained at cost of degradation of the relay user's QoE. On the other hand, cooperative communications can achieve performance similar to that of a conventional multiple-input multiple-output (MIMO) system by forming virtual M1M0 arrays. Hence, to improve the QoE performance of relay users, this article proposes the concept of a belief threshold at the destination user and a new cooperative scheme based on the belief threshold destination (BTD) technique, while without decaying the BER performance of the communication system.     

基于用户体验的VLC/WiFi异构网络切换算法

针对可见光通信(VLC)与WiFi组成的异构网络中的网络选择问题,现有工作大多仅关注实际物理网络指标的优化,如信干噪比(SINR)和吞吐量等,而忽视了终端用户的异构需求和服务体验。基于此,该文提出了一种以用户体验质量(QoE)为优化目标的网络切换算法。该算法首先基于平均主观评分(MOS)机制建立离散化的QoE等级模型,然后根据不同网络对应的实际QoE水平给出了相应网络切换准则,当且仅当新网络使得用户QoE等级提升时才进行网络切换,从而在一定程度减小盲目追求容量优化引起的网络切换开销。仿真结果表明,该算法相比现有算法能够在保证QoE水平的前提下显著减小整体的网络切换次数,从而降低网络开销,提升网络性能。      

Optimization of Training and Scheduling in the Non-Coherent SIMO Multiple Access Channel

Channel state information (CSI) is important for achieving large rates in MIMO channels. However, in time-varying MIMO channels, there is a tradeoff between the time/energy spent acquiring channel state information (CSI) and the time/energy remaining for data transmission. This tradeoff is accentuated in the MIMO multiple access channel (MAC), since the number of channel vectors to be estimated increases with the number of users. Furthermore, the problem of acquiring CSI is tightly coupled with the problem of exploiting CSI through multiuser scheduling. This paper considers a block-fading MAC with coherence time T, n uncoordinated users-each with one transmit antenna and the same average power constraint, and a base station with M receive antennas and no a priori CSI. For this scenario, a training-based communication scheme is proposed and the training and multiuser-scheduling aspects of the scheme are jointly optimized. In the high-SNR regime, the sum capacity of the non-coherent SIMO MAC is characterized and used to establish the SNR-scaling-law optimality of the proposed scheme. In the low-SNR regime, the sum-rate of the proposed scheme is found to decay linearly with vanishing SNR when flash signaling is incorporated. Furthermore, this linear decay is shown to be order-optimal through comparison to the low-SNR sum capacity of the non-coherent SIMO MAC. A by product of these SNR-asymptotic analyses is the observation that non-trivial scheduling (i.e., scheduling a strict subset of trained users) is advantageous at low SNR, but not at high SNR. The sum-rate and per-user throughput are also explored in the large-n and large-M regimes. Non-coherent capacity, training, multiple access channel, multiuser scheduling, opportunistic scheduling.     

A Hybrid Token-CDMA MAC Protocol for Wireless Ad Hoc Networks

Token-passing medium access control (MAC) protocols are gaining interest among wireless ad hoc network researchers as they provide unrivaled advantages over the existing IEEE 802.11 standards. This paper introduces a hybrid token-code division multiple access (CDMA) MAC protocol that is based on a token-passing scheme with the incorporation of CDMA. With its unique CDMA feature, the proposed MAC is able to support multiple simultaneous transmissions. The proposed protocol provides both quality of service (QoS) and high network resource utilization while ensuring the stability of the network. This paper examines the performance of the proposed MAC scheme by simulation and compares its performance against that of other MAC protocols that have appeared in the literature. Simulation results demonstrate that our proposed MAC scheme is effective in decreasing the packet delay and significantly shortens the length of the queue. The input traffic model used in the simulation is a two-state Markov-Modulated Poisson Process (MMPP). The data rate QoS is enforced by implementing a modified leaky bucket mechanism in the proposed MAC scheme. The simulation also takes into account channel link errors caused by the wireless link by implementing a multilayered Gilbert-Elliot model.     

移动自组织网络中的多信道 MAC 调度码的设计与分析

基于有限域上多项式,设计了一类用于支持多类业务移动自组织网络的多信道拓扑透明MAC调度码。这类调度码能够为各类节点提供有保证的服务质量,并且能够利用多信道资源有效地减小码长。性能分析表明,这类拓扑透明MAC调度码在码长以及最小保证吞吐量等方面优于扩展的TDMA固定分配方案。     

Towards real-time anomalies monitoring for QoE indicators

Anomaly detection and characterization is a main topic for network managers. Although quality-of-service (QoS) indicators can help to infer problem occurrence, they do not provide immediate insight on the user’s perceived quality. Evolved service-level agreements (SLA) will likely be established in terms of quality of experience (QoE) indicators. QoS metrics composing the QoE indicators need to be monitored on a real-time basis by the SLA management tools in order to detect anomalies driving to contract violations. Monitoring SLA contracts may involve the surveillance of individual application sessions for several users. In this work, we address the problem of anomaly detection with impact on a relatively large number of users, either on one or on several types of applications simultaneously. We propose a method to characterize the state of the network, representing QoE indicators as time series and reducing the dimension of the data set. The singular spectrum analysis (SSA) method, using a combination of geometric and statistical methods, is proposed as an analysis tool in order to detect anomalies on QoE indicator evolution.