Heterogeneous QoS Research Articles

Path diversified multi-QoS optimization in multi-channel wireless mesh networks

Wireless mesh networks (WMNs) have become a promising solution for quick and low-cost spreading of Internet accesses and other network services. Given the mesh topology, multiple paths are often available between node pairs, which thus naturally endorse path-diversified transmission. Unfortunately, like in wired networks, discovering completely disjoint paths in a WMN remains an intractable problem. It indeed becomes more challenging given the interferences across wireless channels in a WMN, not to mention that applications may demand heterogeneous QoS optimizations across different paths. The availability of multiple channels in advanced WMNs however sheds new lights into this problem. In this paper, we show that, as long as the best channels with different QoS metrics are not overlapped between neighboring node pairs, complete disjoint paths with heterogeneous QoS targets are available in a multi-channel WMN. We present efficient solutions to discover such paths, particularly for bandwidth- and delay-optimization. We also develop novel algorithms for accurately estimating path bandwidth and delay in the multi-channel environment. These lead to the design of a practical protocol that extends the classical Ad hoc On-demand Multi-path Distance Vector (AOMDV). Through extensive simulations, we show that our protocol yields significant improvement over state-of-the-art multi-path protocols in terms of both end-to-end throughput and delay.

A packet scheduling scheme for 4G wireless access systems aiming to maximize revenue for the telecom carriers

Efficient utilization of network resources is a key goal for emerging BWAS. This is a complex goal to achieve due to the heterogeneous service nature and diverse QoS requirements of various applications that BWAS support. Packet scheduling is an important activity that affects BWAS QoS outcomes. This paper proposes a new packet scheduling mechanism that improves QoS in mobile wireless networks which exploit IP as a transport technology for data transfer between BWAS base stations and mobile users at the radio transmission layer. In order to improve BWAS QoS the new packet algorithm makes changes at both the IP and the radio layers. The new algorithm exploits handoff priority scheduling principles and takes into account buffer occupancy and channel conditions. The packet scheduling mechanism also incorporates the concept of fairness. The algorithm offers an opportunity to maximize the carriers' revenue at various traffic situations. Simulation results were compared to well-known algorithms which demonstrated the new packet scheduling algorithm is able to provide a low handoff packet drop rate, low packet forwarding rate, low packet delay, ensure fairness amongst the users of different services and generates higher revenue. Furthermore this research proposes a new and novel measure named "Satisfaction Factor" to measure the efficacy of various scheduling schemes and finally proposes four performance metrics for NodeB's of in Next Generation Wireless Networks.

Exploring blind online scheduling for mobile cloud multimedia services

Mobile cloud is a new emerging technology which can be used to enable users to enjoy abundant multimedia applications in a pervasive computing environment. Therefore, the scheduling of massive multimedia flows with heterogeneous QoS guarantees becomes an important issue for the mobile cloud. Generally, the predominant popular cloud-based scheduling algorithms assume that the request rate and service time, are available for the system operator. However, this assumption can hardly be maintained in many practical scenarios, especially for the largescale mobile cloud. In this article, we consider the scheduling problem for a practical mobile cloud in which the above parameters are unavailable and unknown. Taking into account the performance of the users and the impartial free time among the servers, the highlight of this article lies in proposing a blind online scheduling algorithm (BOSA). Specifically, we assign available multimedia servers based on the last timeslot information of the users' requests, and route all the multimedia flows according to the first-come- first-served rule. Moreover, we design detailed steps to apply the BOSA to a content recommendation system, and show that the proposed BOSA can achieve asymptotic optimality.

Introducing multi-ID and multi-locator into network architecture

The present-day Internet has no separate namespace for host IDs. It uses IP addresses as host IDs, which are in fact locators. This dual role is problematic for mobility, multihoming, security, and routing on the Internet. To solve these problems, research has recently begun on ID/locator split architectures. Some standardization activities based on this concept are also progressing in ITU-T Study Group 13 and in the IETF. We expect that introduction of the ID/locator split concept into the new generation network or future Internet architecture can bring about additional functions, such as heterogeneous network protocol support, multicast, QoS, resource or service discovery, and flexible human-network interaction. Toward realization of these functions, this article discusses some approaches to introducing multi-ID and multilocator support into the network architecture. This also lists items that have the potential to be investigated and standardized in ITU-T.

Joint resource allocation for WLAN&WCDMA integrated networks based on spectral bandwidth mapping

Next wireless network aims to integrate heterogeneous wireless access networks by sharing wireless resource. The spectral bandwidth mapping concept is proposed to uniformly describe the resource in heterogeneous wireless networks. The resources of codes and power levels in WCDMA system as well as statistical time slots in WLAN are mapped into equivalent bandwidth which can be allocated in different networks and layers. The equivalent bandwidth is jointly distributed in call admission and vertical handoff control process in an integrated WLAN/WCDMA system to optimize the network utility and guarantee the heterogeneous QoS required by calls. Numerical results show that, when the incoming traffic is moderate, the proposed scheme could receive 5%–10% increase of system revenue compared to the MDP based algorithms.

A Web Service Selection Algorithm Based on Multiple QoS Registration Centers and Heterogeneous QoS Model

多QoS注册中心并且QoS模型异构给服务选择带来巨大困难。借鉴多属性群决策(MAGDM)理论的基本思想，该文提出一种解决上述难题的多注册中心和模型异构的Web服务选择算法(MRHQ_WSSA)。MRHQ_ WSSA算法能综合评估各QoS注册中心的QoS信息，从而获得QoS综合最优的服务组合计划。MRHQ_WSSA算法包括5个步骤：用户偏好规格化、群偏好确定、加权规格化决策矩阵、确定群理想方案、计算群贴近度。最后通过实验验证算法的优势和有效性。

Efficient Adaptation Decision Making Algorithms for Context-Aware Applications

The current trend toward ubiquitous and autonomic computing leads to the necessity to realize adaptive applications. The environment of applications becomes more heterogeneous and user QoS needs and resource availability vary heavily. To maintain the usability, availability and reliability of these applications, adaptive behavior is needed. In this paper, the authors examine the decision-making phase in realizing adaptive behavior of an application. Algorithms reason about the adaptive application and the current context with the goal of selecting a new application variant that better fits the environment. This reasoning happens in a search space that is very complex and consequently poses a problem toward scalability; even when applications are relatively small. Therefore, the authors present two novel algorithms that handle the complex search space in an intelligent way. In this paper, both algorithms are introduced along with a thorough evaluation of their behavior and scalability.

Fuzzy Multi-Attribute Decision Making-Based Algorithm for Semantic Web Service Composition

Choosing the global optimal execution plan is an important process in the semantic Web service composition. The plan selection based on QoS is still challenging because the heterogeneous QoS values make data aggregation and decision making hard. This paper presents a novel Fuzzy Multi-attribute decision making-based semantic Web service Composition algorithm (FuMuCom) to solve the above difficulties for the first time. FuMuCom takes all possible QoS expression types (real number, interval and linguistic expression) into consideration. It includes three main steps: defuzzifying linguistic data, normalizing the decision matrix and evaluating alternatives synthetically. Other contributions of the paper include an extensible QoS ontology to express the heterogeneous QoS values, an ontology evolution strategy for aggregating QoS and a set of experiments that demonstrate the benefits and effectiveness of our approach.

Multiclass G/M/1 queueing system with self-similar input and non-preemptive priority

In order to deliver innovative and cost-effective IP multimedia applications over mobile devices, there is a need to develop a unified service platform for the future mobile Internet referred as the Next Generation (NG) all-IP network. It is convincingly demonstrated by numerous recent studies that modern multimedia network traffic exhibits long-range dependence (LRD) and self-similarity. These characteristics pose many novel and challenging problems in traffic engineering and network planning. One of the major concerns is how to allocate network resources efficiently to diverse traffic classes with heterogeneous QoS constraints. However, much of the current understanding of wireless traffic modeling is based on classical Poisson distributed traffic, which can yield misleading results and hence poor network planning. Unlike most existing studies that primarily focus on the analysis of single-queue systems based on the simplest First-Come-First-Serve (FCFS) scheduling policy, in this paper we introduce the first of its kind analytical performance model for multiple-queue systems with self-similar traffic scheduled by priority queueing to support differentiated QoS classes. The proposed model is based on a G/M/1 queueing system that takes into account multiple classes of traffic that exhibit long-range dependence and self-similarity. We analyze the model on the basis of non-preemptive priority and find exact packet delay and packet loss rate of the corresponding classes. We develop a finite queue Markov chain for non-preemptive priority scheduling, extending the previous work on infinite capacity systems. We extract a numerical solution for the proposed analytical framework by formulating and solving the corresponding Markov chain. We further present a comparison of the numerical analysis with comprehensive simulation studies of the same system. We also implement a Cisco-router based test bed, which serves to validate the mathematical, numerical, and simulation results as well as to support in understanding the QoS behaviour of realistic traffic input.

Interworking of heterogeneous access networks and QoS provisioning via IP multimedia core networks

Moving towards packet networks, where IP will have a prominent role, constitutes nowadays a widely accepted perception of future communications, the first instance of which has begun to materialise with the IP multimedia core network subsystem (IMS). By specification, IMS is the first implementation towards reaching converged communications which allows users to communicate with video, audio and multimedia content, via any fixed, mobile and wireless access network type, with controllable QoS. To enable IMS communications across heterogeneous networks, incorporating UMTS, WLAN and fixed IP access points, 3GPP and ETSI's TISPAN currently work on schemes for controlling bandwidth allocation at the service level by employing logical interfaces that carry SIP messages. This article analyzes how interconnection between such heterogeneous networks may be performed on real platforms. In this effort, special attention is paid to the way the various interconnection possibilities can affect end-to-end QoS provisioning.

An OFDM-TDMA/SA MAC Protocol with QoS Constraints for Broadband Wireless LANs

Orthogonal frequency division multiplexing (OFDM) is an important technique to support high speed transmission of broadband traffic in wireless networks, especially broadband wireless local area networks (LANs). Based on OFDM, a new multiple access scheme, called OFDM-TDMA with subcarrier allocation (OFDM-TDMA/SA), is proposed in this paper. It provides more flexibility in resource allocation than other multiple access schemes such as OFDM-TDMA, OFDM-frequency division multiple access (OFDM-FDMA), and orthogonal frequency division multiple access (OFDMA). With OFDM-TDMA/SA, a medium access control (MAC) is designed for broad-band wireless LANs. It optimizes bit allocation in subcarriers so that maximum bits are transmitted in each OFDM symbol under a frequency selective fading environment. The OFDM-TDMA/SA MAC protocol also supports three classes of traffic such as guaranteed, controlled-load, and best effort services. Based on the optimum subcarrier bit-allocation algorithm and considering heterogeneous QoS constraints of multimedia traffic, a hierarchical scheduling scheme is proposed to determine the subcarriers and time slots in which a mobile terminal can transmit packets. In such a way, the OFDM-TDMA/SA MAC protocol significantly increases system throughput in a frequency selective fading environment and guarantees QoS of multimedia traffic. Computer simulation is carried out to evaluate the performance of the OFDM-TDMA/SA MAC protocol. Results show that the new MAC protocol outperforms other MAC protocols for OFDM-based wireless LANs.

Scalable Quasi-Dynamic-Provisioning-Based Admission Control Mechanism in Differentiated Service Networks

The architecture in a differentiated services (diffServ) network is based on a simple model that applies a per-class service in the core node of the network. However, because the network behavior is simple, the network structure and provisioning is complicated. If a service provider wants dynamic provisioning or a better bandwidth guarantee, the differentiated services network must use a signaling protocol with QoS parameters or an admission control method. Unfortunately, these methods increase the complexity. To overcome the problems with complexity, we investigated scalable dynamic provisioning for admission control in DiffServ networks. We propose a new scalable qDPM 2 mechanism based on a centralized bandwidth broker and distributed measurement-based admission control and movable boundary bandwidth management to support heterogeneous QoS requirements in DiffServ networks.

Performance analysis of an output queueing ATM switch with heterogeneous traffic and multiple QoS

The authors analyse an output queueing ATM switch which has the bandwidth-oriented priority (BOP) Markovian service scheme under the condition of heterogeneous traffic and multiple QoS. By designing the output queue service scheme in which heterogeneous traffic classes are separated by using separate buffers and the service to each buffer is done according to the BOP Markovian polling scheme, the server of an output queue is modelled as an independent geometric server (IGS) for each traffic class. This control method enables handling heterogeneous traffic, control of QoS and calculation of the equivalent bandwidth of each traffic to be independent. To find the equivalent bandwidth (EB) of a traffic class, the authors present an analysis which is based on the matrix-geometric analysis method. The output queue is modelled by multiple MMBBP/Geom/1/K queueing systems, one for each traffic class. Among several QoS parameters, the authors focus on the cell loss probability. The analysis is verified by simulation in measures of average queue length as well as cell loss probability. A connection admission control (CAC) method which calculates the EB of connections including a newly arriving cell by the iterative approach using the EB of the previous connection is also described.