Resource Allocation in OFDMA Wireless Communications Systems Supporting Multimedia Services

We design a resource allocation algorithm for downlink of orthogonal frequency division multiple access (OFDMA) systems supporting real-time (RT) and best-effort (BE) services simultaneously over a time-varying wireless channel. The proposed algorithm aims at maximizing system throughput while satisfying quality of service (QoS) requirements of the RT and BE services. We take two kinds of QoS requirements into account. One is the required average transmission rate for both RT and BE services. The other is the tolerable average absolute deviation of transmission rate (AADTR) just for the RT services, which is used to control the fluctuation in transmission rates and to limit the RT packet delay to a moderate level. We formulate the optimization problem representing the resource allocation under consideration and solve it by using the dual optimization technique and the projection stochastic subgradient method. Simulation results show that the proposed algorithm well meets the QoS requirements with the high throughput and outperforms the modified largest weighted delay first (M-LWDF) algorithm that supports similar QoS requirements.     

Analytical evaluation of hybrid feedback scheme for OFDMA system

This paper first introduces the performance analysis of two classical channel quality indicator （CQI） feedback schemes which are best-n feedback and the threshold based feedback and derives the mathematical expressions of average capacity which is described by Theorem 1 and 2. Then, a reduced feedback scheme is designed for multiple traffics and multi-channel. The novel scheme combines the best-n feedback and the threshold based feedback together to reduce the feedback overhead. The proposed scheme can not only guarantee the quality of service （QoS） requirement of real time （RT） traffic but also reduce feedback overhead at the cost of a marginal increased downlink overhead. Simulation results demonstrated the good performance of the proposed feedback scheme.     

Optimal partition of QoS requirements with discrete cost functions

The future Internet is expected to support applications with quality of service (QoS) requirements. To this end, several mechanisms are suggested in the IETF; the most promising among them is DiffServ. An important problem in this framework is how to partition the QoS requirements of an application along a selected path. The problem which is, in general, NP-complete, was solved for continuous convex cost functions by Lorenz and Orda (see IEEE/ACM Trans. Networking. vol.6, p.768-78, 1998 and Proc. IEEE INFOCOM'99, p.246-53, 1999). This paper concentrates on discrete cost functions, which better model the existing and upcoming mechanisms in the Internet. We present efficient exact and approximated solutions for various conditions of the problem. We also show that although the more complex problem of QoS sensitive routing with discrete cost functions is hard, it has a fully polynomial approximation scheme     

安全保障：无线Mesh网络中支持QoS的DSR路由协议的改进与实现

随着无线Mesh网络传输多媒体业务需求的增加,要求网络支持服务质量（QoS）,本文基于DSR协议设计了一个支持QoS的路由协议算法QDSR（QoS-DSR）。该算法保证了数据流的带宽、时延的QoS需求,根据路径跳数和节点拥塞情况定义路由代价函数,选择最优路径。仿真结果表明,与DSR相比,QDSR提高了网络吞吐量,降低了平均端到端延时,提高了网络利用率,更好地满足业务的QoS需求,并且具有更强的适用性和可扩展性。     

A novel scheduling scheme for multiple traffic classes

In this paper, a novel scheduling scheme is proposed for multiple traffic classes to exploit multiuser diversity of the non-real-time (NRT) traffic. The proposed scheduling algorithm consists of two stages, i.e. at the first scheduling stage, the inter-traffic scheduler dynamically allocates the bandwidth resources to each traffic class by a periodic and triggered way with the objective of maximizing a room for NRT traffic while guaranteeing the quality of service (QoS) requirements of real-time (RT) traffics; at the second scheduling stage, the intra-traffic scheduler is used to schedule different users' packets within each traffic class simultaneously. The proposed algorithm not only enhances the system throughput but also satisfies the QoS requirements of RT traffic. Simulation results validate the effectiveness and good performance of the proposed scheme.     

A terminal‐controlled vertical handover decision scheme in IEEE 802.21‐enabled heterogeneous wireless networks

The seamless internetworking among heterogeneous networks is in great demand to provide ‘always‐on’ connectivity services with quality of service (QoS) provision, anywhere at anytime. The integration of wireless‐fidelity (Wi‐Fi) and wireless metropolitan area networks (WiMAX) networks can combine their best features to provide ubiquitous access, while mediating the weakness of both networks. While it is challenging to obtain optimized handover decision‐based dynamic QoS information, users can improve their perceived QoS by using the terminal‐controlled handover decision in a single device equipped with multiple radio interfaces. The IEEE 802.21 aims at providing a framework that defines media‐independent handover (MIH) mechanism that supports seamless handover across heterogeneous networks. In this paper, an multiple attributes decision making‐based terminal‐controlled vertical handover decision scheme using MIH services is proposed in the integrated Wi‐Fi and WiMAX networks to provide ‘always‐on’ connectivity QoS services. The simulation results show that the proposed scheme provides smaller handover times and lower dropping rate than the RSS‐based and cost function‐based vertical handover schemes. Copyright © 2009 John Wiley & Sons, Ltd.     

Class-based quality of service over air interfaces in 4G mobilenetworks

We present a framework for quality of service provisioning over the air interfaces in future wireless networks, including 3G enhancement and 4G mobile networks. The framework is based on the paradigm of service classes, wherein each class can exhibit a characteristic behavior in terms of resource allocation over the air interface. Using this QoS framework, future wireless network operators can define their own sets of service classes, choose the preferred way of implementing the QoS behavior of these classes, and offer class-based pricing schemes. The user application can choose the service class that best suits its expectations in terms of QoS and cost of access. A class-based bandwidth scheduling scheme is described as a mechanism to implement this QoS framework over CDMA air interfaces. This scheme incorporates the paradigm of service classes, in conjunction with fair resource allocation and air interface congestion resilience, while allocating air interface bandwidth to mobile users     

Quality of service in telecommunications. I. Proposition of a QoSframework and its application to B-ISDN

The the quality of service (QoS) concept is becoming an ever more important issue in telecommunication and computer communication. The article focuses on the QoS notion and concept. The definition of QoS in the International Telecommunications Union-Telecommunications Sector (ITU-T) recommendations and the International Standards Organization (ISO) standards is analysed. Little is known about the asynchronous transfer mode (ATM) performance requirements of the broadband integrated services digital network (B-ISDN) services, especially for multimedia applications. This is because the ATM performance requirements of multimedia applications depend not only on the diverse QoS requirements from application and user, but also on the protocol stacks and scheduling in end systems. Therefore, in order to guarantee QoS to the user, it is necessary to introduce a set of QoS parameters whose properties indicate the nature and requirements of the layered protocol stack. We describe how a proposed QoS framework can be applied to B-ISDN as a specific network. The QoS aspects related to B-ISDN signaling (the control plane) and the QoS aspects related to layer and plane management (the management plane) are described. We also describe how the QoS framework resides in a protocol stack and works together with the B-ISDN network management and signaling     

A resource‐tuned QoS multicast routing protocol

This paper presents a novel framework for quality‐of‐service (QoS) multicast routing with resource allocation that represents QoS parameters, jitter delay, and reliability, as functions of adjustable network resources, bandwidth, and buffer, rather than static metrics. The particular functional form of QoS parameters depends on rate‐based service disciplines used in the routers. This allows intelligent tuning of QoS parameters as functions of allocated resources during the multicast tree search process, rather than decoupling the tree search from resource allocation. The proposed framework minimizes the network resource utilization while keeping jitter delay, reliability, and bandwidth bounded. This definition makes the proposed QoS multicast routing with resource allocation problem more general than the classical minimum Steiner tree problem. As an application of our general framework, we formulate the QoS multicast routing with resource allocation problem for a network consisting of generalized processor sharing nodes as a mixed‐integer quadratic program and find the optimal multicast tree with allocated resources to satisfy the QoS constraints. We then present a polynomial‐time greedy heuristic for the QoS multicast routing with resource allocation problem and compare its performance with the optimal solution of the mixed‐integer quadratic program. The simulation results reveal that the proposed heuristic finds near‐optimal QoS multicast trees along with important insights into the interdependency of QoS parameters and resources.     

A Shared Buffer‐Constrained Topology Reconfiguration Scheme in Wavelength Routed Networks

The reconfiguration management scheme changes a logical topology in response to changing traffic patterns in the higher layer of a network or the congestion level on the logical topology. In this paper, we formulate a reconfiguration scheme with a shared buffer‐constrained cost model based on required quality‐of‐service (QoS) constraints, reconfiguration penalty cost, and buffer gain cost through traffic aggregation. The proposed scheme maximizes the derived expected reward‐cost function as well as guarantees the required flow's QoS. Simulation results show that our reconfiguration scheme significantly outperforms the conventional one, while the required physical resources are limited.     

Optimal partition of QoS requirements on unicast paths andmulticast trees

We investigate the problem of optimal resource allocation for end-to-end QoS requirements on unicast paths and multicast trees. Specifically, we consider a framework in which resource allocation is based on local QoS requirements at each network link, and associated with each link is a cost function that increases with the severity of the QoS requirement. Accordingly, the problem that we address is how to partition an end-to-end QoS requirement into local requirements, such that the overall cost is minimized. We establish efficient (polynomial) solutions for both unicast and multicast connections. These results provide the required foundations for the corresponding QoS routing schemes, which identify either paths or trees that lead to minimal overall cost. In addition, we show that our framework provides better tools for coping with other fundamental multicast problems, such as dynamic tree maintenance     

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.     

QoS-aware computational method for IoT composite service

This paper integrated the quality of service (QoS) requirements of Internet of things (IoT) composite services, and put forward effective decomposition and optimization methods of the QoS metrics. The authors break down the complex QoS calculation model into four basic models, and each model is given a computational method. Combined with the QoS technology of the composite service, the authors adopt the algorithm to find the sub-optimal service with an acceptable cost under the QoS constraints. The proposed algorithm can quickly provide QoS computing services than other two algorithms for large-scale IoT compose services.     

Bandwidth-aware routing and admission control for efficient video streaming over MANETs

In this paper, we develop and evaluate an adaptive self-configurable routing framework that can deal with dynamic nature of mobile ad hoc networks and provides quality-of-service (QoS) guarantees for efficient video streaming. Proposed framework mainly consists of two major components. Firstly, it is a reactive bandwidth-aware node-disjoint multipath routing protocol which determines routes based on the specified bandwidth requirements of the requesting application. The second component of the framework is a session admission control (SAC) process that permits or denies a session to enter into the network based on the current availability of network bandwidth. We also propose methods to handle QoS violations caused by network mobility and congestion by keeping backup routes, performing local route recovery, avoiding routing through short-lived low quality links and periodic monitoring of the active transmission routes. To verify our proposed algorithms, the network with H.264/SVC encoded video traces which are generated from real-time video traffic is used for modeling the behaviour of the source nodes. It has been observed that reactively discovered and maintained routes on the basis of the most recent information about network topology and available resources can significantly improve the admission decision accuracy of SAC process, in turn improving the quality of received video traffic significantly.

     

A web service‐based internet of things framework for mobile resource augmentation

Mobile devices are the primary communication tool in day to day life of the people. Nowadays, the enhancement of the mobile applications namely IoTApps and their exploitation in various domains like healthcare monitoring, home automation, smart farming, smart grid, and smart city are crucial. Though mobile devices are providing seamless user experience anywhere, anytime, and anyplace, their restricted resources such as limited battery capacity, constrained processor speed, inadequate storage, and memory are hindering the development of resource‐intensive mobile applications and internet of things (IoT)‐based mobile applications. To solve this resource constraint problem, a web service‐based IoT framework is proposed by exploiting fuzzy logic methodologies. This framework augments the resources of mobile devices by offloading the resource‐intensive subtasks from mobile devices to the service providing entities like Arduino, Raspberry PI controller, edge cloud, and distant cloud. Based on the recommended framework, an online Repository of Instructional Talk (RIoTalk) is successfully implemented to store and analyze the classroom lectures given by faculty in our study site. Simulation results show that there is a significant reduction in energy consumption, execution time, bandwidth utilization, and latency. The proposed research work significantly increases the resources of mobile devices by offloading the resource‐intensive subtasks from the mobile device to the service provider computing entities thereby providing Quality of Service (QoS) and Quality of Experience (QoE) to mobile users.     

Cross layer scheduling for real-time traffic in multiuser MIMO-OFDMA systems

A novel cross layer scheduling algorithm is proposed for real-time (RT) traffic in multiuser downlink multiple-input multiple-output orthogonal frequency division multiple access (MIMO-OFDMA) wireless systems. The algorithm dynamically allocates resources in space, time and frequency domain based on channel state information (CSI), users' quality of service (QoS) requirements and queue state information (QSI). To provide higher data rate and spectrum efficiency, adaptive modulation and coding (AMC) is employed. The proposed algorithm can improve cell throughput and increase the number of users that can be supported while guaranteeing users' QoS requirements and fairness among all users. Simulation results indicate that the proposed algorithm can achieve superior performance.     

Performance analysis of a channel allocation scheme for multi‐service mobile cellular networks

This paper presents a new channel allocation scheme, namely the dynamic partition with pre‐emptive priority (DPPP) scheme, for multi‐service mobile cellular networks. The system is modelled by a two‐dimensional Markov process and analysed by the matrix‐analytic method. A pre‐emptive priority (PP) mechanism is employed to guarantee the quality of service (QoS) requirement of the real‐time (RT) traffic at the expense of some degradation of non‐real‐time (NRT) traffic, while the victim buffer compensates the degradation and has no negative impact on the RT traffic. The complete service differentiation between new calls and handoff calls from different traffic classes is achieved by using the dynamic partition (DP) concept with the help of related design parameters. The performance analysis and numerical results show that the DPPP scheme, compared with the existing schemes, is effective and practical in multi‐service environments. Copyright © 2006 John Wiley & Sons, Ltd.     

基于场景的移动应用服务QoS建模与评估

针对目前静态服务QoS建模难以有效表征移动应用服务QoS的时变性和位置相关性,构建基于场景的移动应用服务QoS模型。定义移动应用服务QoS指标体系并构建了QoS数值对矩阵,提出服务QoS总体评估、特定区域或特定时段评估、热点区域或繁忙时段评估3类评估问题。采用遗传算法和数据聚类算法,通过服务请求位置密度实现区域自动划分,通过服务请求频次实现时段自动划分,量化位置区域和时间这2个场景条件,根据限定条件重构QoS数值对矩阵,基于QoS数值对矩阵的统计分析给出了服务QoS评估方法。最后阐述QoS归一化评估和应用框架。     

Improved MLWDF scheduler for LTE downlink transmission

In long-term evolution (LTE) downlink transmission, modified least weighted delay first (MLWDF) scheduler is a quality of service (QoS) aware scheduling scheme for real-time (RT) services. Nevertheless, MLWDF performs below optimal among the trade-off between strict delay and loss restraints of RT and non-RT traffic flows, respectively. This is further worsened with the implementation of hybrid automatic retransmission request (HARQ). As these restraints grow unabated with increasing number of user demands, the performance of MLWDF further reduces. In order to ameliorate this situation, there is a need to directly incorporate the variations in user demands and HARQ implementation as parameters to the MLWDF scheduler. In this work, an improvement to the MLWDF scheduler is proposed. The improvement entails adding two novel parameters that characterise user demand and HARQ implementation. The scheduler was tested using varying three classes of service in QoS class identifiers (QCIs) table standardised by Third Generation Partnership Project for LTE network to characterise different services. It was also tested on the basis of packet prioritisation. The proposed scheduler was simulated with LTE-SIM simulator and compared with the MLWDF and proportional fairness schedulers. In terms of delay, throughput and packet loss ratio; the proposed scheduler increased overall system performance.     

Novel wavelength and bandwidth allocation algorithms for WDM EPON with QoS support

Ethernet passive optical networks (EPONs) have been considered as the one of the most promising candidates for next-generation access networks. However, the EPON architecture although cost effective is bandwidth limited and quality of service (QoS) support is still a major concern. In this paper, we propose a cost-efficient wavelength division multiplexing (WDM) EPON architecture. We present two wavelength and bandwidth allocation algorithms with full QoS support to fulfill all requirements of new application and services in a converged triple play network. We analyze and compare the presented models and algorithms in terms of delay, jitter, queue occupancy, throughput and overall system performance. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed architecture and algorithms.