QoS Support Research Articles

Modelling of Differentiated Bandwidth Requests in IEEE 802.16m Systems

In order to support a large number of mobile stations (MSs) with statistical multiplexing in cellular networks, a random access scheme is widely used for uplink (UL) bandwidth request (BR). In the design of a random access based BR scheme, there are two important requirements: short connection delay and diverse Quality of Services (QoSs) support. Such requirements are crucial for IMT-Advanced systems like IEEE 802.16m to provide various types of fourth generation (4G) data services. IEEE 802.16m provides advanced UL BR schemes for non-real time polling service (nrtPS) and best-effort (BE) service to meet the requirements of short connection time and multiple QoS level support. In order to provide short connection time and multiple QoS support, three-step and differentiated BR procedures are adopted. In this paper, a novel modelling of IEEE 802.16m contention based BR scheme is proposed that uses a 2-dimensional discrete time Markov chain. Both the short access delay three-step BR procedures and normal five-step BR procedure are considered in the model. Our proposed model also incorporates the IEEE 802.16m differentiated BR procedure. With the proposed model, we extensively evaluate the performance of IEEE 802.16m BR for two different service classes by changing QoS parameters, such as backoff window size and BR timer. Computer simulations are performed to corroborate the accuracy of the proposed model for various operation scenarios. With the proposed model, accurate QoS parameter values can be derived for the IEEE 802.16m contention-based BR scheme.

Finer Tuning Of QoS Mechanisms for Performance Enhancement of Wireless Networks

WLAN is supported by almost all of the modern communication devices. These devices are largely used for communication of multimedia data including real time data. There is limited QoS support in WLANs, which will become an impediment in deploying multimedia applications. The important QoS metrics for multimedia applications are delay, jitter, loss, and throughput. There are different mechanisms and techniques for controlling these metrics. A lot of work has been carried out as far as loss and throughput is concerned. This paper focuses mainly on reducing the delay and jitter. A study of the various QoS support mechanisms for wireless networks is carried out and suggestions for improvement have been proposed particularly pertaining to the MAC parameters which will lead to a more precise and finer tuning of the already available mechanisms.

A ring-based multicast routing topology with QoS support in wireless mesh networks

Wireless mesh networking (WMN) is an emerging technology for future broadband wireless access. The proliferation of the mobile computing devices that are equipped with cameras and ad hoc communication mode creates the possibility of exchanging real-time data between mobile users in wireless mesh networks. In this paper, we argue for a ring-based multicast routing topology with support from infrastructure nodes for group communications in WMNs. We study the performance of multicast communication over a ring routing topology when 802.11 with RTS/CTS scheme is used at the MAC layer to enable reliable multicast services in WMNs. We propose an algorithm to enhance the IP multicast routing on the ring topology. We show that when mesh routers on a ring topology support group communications by employing our proposed algorithms, a significant performance enhancement is realized. We analytically compute the end-to-end delay on a ring multicast routing topology. Our results show that the end-to-end delay is reduced about 33 %, and the capacity of multicast network (i.e., maximum group size that the ring can serve with QoS guarantees) is increased about 50 % as compared to conventional schemes. We also use our analytical results to develop heuristic algorithms for constructing an efficient ring-based multicast routing topology with QoS guarantees. The proposed algorithms take into account all possible traffic interference when constructing the multicast ring topology. Thus, the constructed ring topology provides QoS guarantees for the multicast traffic and minimizes the cost of group communications in WMNs.

Admission Control Scheme for QoS Support in IEEE 802.11e Wireless LAN

Admission Control Scheme for QoS Support in IEEE 802.11e Wireless LAN

Core Based Group Communication with Qos Support

The present day is demanding more and more quality of service in broadband group communication to support huge access of internet service and multimedia application. The core based solution is able to full fill this demand a lot. In this paper effort has been put to make it more flexible in comparison to SPAN/COST through a new approach which can be an alternative solution of SPAN/ADJUST for solving the constrained of non singular core solution.

Implementation of Cellular IP and Its Performance Analysis

In the current Cellular IP architecture, only one gateway serves the entire CIP network. So, the gateway is single point of failure for all the mobile hosts who rely on it to be connected to the Internet. Cellular IP requires that a mobile host be using exactly one gateway to the Internet backbone with Mobile IP at a time. When multiply gateways are used in a cellular IP network, the optimal design for the multiple domains is needed. The cellular IP protocol provides better performance for hand-off than other protocol using micro- mobility. A set of base station cluster together on the same cellular IP network. This kind of domain base network is superior to mobile IP in support of routing optimization and QoS. Experiment were conduct to explore load our protocol and survey the packet loss. This result so that the load of control packet is negligible for cellular IP and the number of lost packet can be successfully reduced. This thesis developed to design cellular IP architecture and fault detection mechanism and recover the protocol of cellular IP. Keywords; Protocol Overview, Network Model, Routing, Handoff, Paging, Security, Implement Cellular IP Network Model, Protocol Details, Simulation Results, Conclusions.

Data Center Network Virtualization: A Survey

With the growth of data volumes and variety of Internet applications, data centers (DCs) have become an efficient and promising infrastructure for supporting data storage, and providing the platform for the deployment of diversified network services and applications (e.g., video streaming, cloud computing). These applications and services often impose multifarious resource demands (storage, compute power, bandwidth, latency) on the underlying infrastructure. Existing data center architectures lack the flexibility to effectively support these applications, which results in poor support of QoS, deployability, manageability, and defence against security attacks. Data center network virtualization is a promising solution to address these problems. Virtualized data centers are envisioned to provide better management flexibility, lower cost, scalability, better resources utilization, and energy efficiency. In this paper, we present a survey of the current state-of-the-art in data center networks virtualization, and provide a detailed comparison of the surveyed proposals. We discuss the key research challenges for future research and point out some potential directions for tackling the problems related to data center design.

A Workload Analysis of Live Event Broadcast Service in Cloud

The class of popular Internet live events, such as sports game broadcast services, can greatly benefit from cloud technology that employs resource pooling and rapid elasticity in resource allocation and management. The external demands tend to be unpredictable and exhibit a high degree of burstability. To sustain a good viewing experience for the users, an important QoS support for this class of applications is the peak load management in the presence of unpredictable demand. This relies on a close grasp of the demand behavior characteristics and an accurate prediction model for them. In this paper, we analyze live sports event broadcast service workloads from a commercial Internet service provider. Our results show that popularity follows a 2-mode Zipf distribution. We also observe some significant characteristics of the demand behavior. First, the demand behavior may differ significantly between games. Popular events tend to exhibit highly variable behaviors in time, volume and the change rate during the course. Finally, the demand variation highly correlates with certain event-specific time points. We conclude the paper with a preliminary study that applies three simple statistical models in workload prediction at runtime as an input to dynamic resource resizing in a cloud. The results indicate that more e ective ways are needed to better capture the dynamics and unpredictability of the workload to improve prediction accuracy.

Wireless Sensor Network Using Six Sigma Multi Hop Routing

The most significant problem in the design of wireless sensor networks is to coordinate the sensors with dynamism into a wireless communication network and route sensed data to the base station. The energy efficiency is the most important key point of the network routing designing. This paper presents the efficient multi hop routing algorithm to extend the lifetime of sensor networks and focuses by employing six sigma principles to obtain the Quality of Service. To attain QoS support, we have to find either a route to assure the application requirements or offering network response to the application when the requirements cannot be met.

An energy aware enhanced AODV routing protocol in MANET

As the growth of multimedia communication in mobile ad hoc networks MANETs, every node needs to conserve its power since most nodes are powered by a battery source. Mobile ad hoc networking is a challenging task due to the lack of resources in the network as well as the frequent changes in network topology. Although lots of research has been done on supporting QoS in the internet and other networks, but they are not suitable for mobile ad hoc networks and still QoS support for such networks remains an open problem. In this paper, we propose that the enhanced ad hoc on-demand distance vector AODV routing protocol which is modified to improve the networks lifetime in mobile ad hoc network MANET. The new scheme has been proposed for achieving QoS in terms of packet delivery, better power management and stable routes. The proposed scheme has been incorporated using AODV protocol.

MAC and Routing Layer Supports for QoS in MANET: A Survey

In Mobile ad hoc networks (MANET), Providing QoS guarantee is difficult task due to unreliable Wireless nature of Link, Mobility, Lacking of Centralized Coordination and Channel contention. For Real-time applications (such as video, audio) QoS is More important on transmissions. Many efforts are put on ad hoc networks at both the MAC and routing layers Meanwhile, QoS aware issues are considered in both MAC and routing layers for ad hoc networks. However QoS can ensure by Admission control protocols and reservation mechanisms. This paper aims to investigate factors affecting QoS, admission control protocols, QoS routing protocols, reservation mechanisms, and MAC Layer QoS Supports. This is also aims to provide deep view of QoS in MANET Of current and Future trends.

B3G 이종 액세스 망에서의 자원관리 프레임워크 연구

상이한 망이 공존하는 LTE-Advanced에서 기존 음성 서비스에 적용된 절차적이고 정적인 제어방식으로는 서비스 연속성을 효과적으로 지원하는 것은 현실적으로 어렵다고 여겨진다. 본 연구에서는 QoS 지원을 기반으로 서비스 연속성을 효과적으로 지원하기 위한 자원 관리 프레임워크를 제시하고자 한다. 제안된 자원 관리 프레임워크는 이동 단말기 및 기지국의 상태 정보 변화에 따라 관련 기능-ISHO, 셀 선정, 자원 할당, 부하 제어, QoS 매핑 등-의 설정을 동적으로 제어하고, 각각의 기능들이 변화에 적응하여 조정되고 재구성하는 과정을 주고받으면서 서비스 연속성을 만족시키기 위하여 상호 작용한다. 이를 위하여 4 종류의 ISHO를 지원하기 위한 각 모듈간의 연계 순서도를 기술하고, ISHO 시나리오가 고려된다. In LTE-Advanced that different networks coexist, it is considered that it is actually difficult to provide service continuity with a procedural and static control method applied to the existing voice service. This research suggests a resource management framework to support the service continuity effectively based on QoS support. In other words, as context information of mobile terminal and base station changes, set-up of related functions such as ISHO, cell selection, source allocation, load control, and QoS mapping is adapted; each function fits into the change, exchanges the process of reorganization, and interacts; these actions go toward to satisfy service continuity. For this aim, the sequence diagram between the function modules for supporting four kind of ISHO is described and then a scenario for ISHO is considered.

A Qos Support Solution for PSVIOQ-CICQ

A Qos Support Solution for PSVIOQ-CICQ

Efficient Routing Protocol to Support QoS in Wireless Mesh Network

The wireless mesh network is a new emerging technology that will change the world of industrial networks connectivity to more efficient and profitable. Mesh networks consist of static wireless nodes and mobile customer; have emerged as a key technology fornew generation networks. The Quality of Service (QOS) is designed to promote and support multimedia applications (audio and video), real time. However guarantee of QoS on wireless networks is a difficult problem by comparison at its deployment in a wired IP network. In this paper, we present an efficient routing protocol named as “QoS- Cluster Based Routing Protocol” (Q-CBRP) to support QoS in Wireless Mesh Network.

Cross‐layer packet scheduler for QoS support over Digital Video Broadcasting‐Second Generation broadband satellite systems

SUMMARYThis article presents a cross‐layer packet scheduler to provide end‐to‐end QoS guarantees for Digital Video Broadcasting‐Second Generation (DVB‐S2) broadband satellite systems. The scheduler design is based on a cross‐layer mechanism defined between the physical and the network layer. It includes an algorithm to guarantee the required QoS specifications established in the service level agreement. The algorithm calculation depends basically on two parameters: the available bandwidth present in a DVB‐S2 satellite link and the QoS requirements of each traffic class defined by the satellite operator. The cross‐layer scheduler's operation is demonstrated using the NS‐2 simulator tool. The results show that the proposed mechanism maximizes the bandwidth utilization while enforcing the priority level of each service class when an extreme reduction of bandwidth caused by rain events is experienced. Copyright © 2012 John Wiley & Sons, Ltd.

A Call Admission Control Scheme for Multimedia Support Over IEEE 802.11 Wireless LANs

These days there is an increasing interest for VoIP over wireless LANs. QoS support for real-time services like voice in the IEEE 802.11 WLAN is an important issue. Since IEEE 802.11 uses contention based MAC protocol – the distributed coordination function DCF, it is difficult to support the strict QoS requirements for voice in these networks. In this thesis a call admission scheme called “CAC” is proposed to achieve this goal, without changing the basic channel access mechanism of IEEE 802.11. CAC scheme regulates the arriving traffic in the wireless network to efficiently coordinate the medium among the contending traffic sources so that the network operates at optimal point, supporting the QoS requirements as well as providing better channel utilization. In this proposal, majority of available bandwidth is allocated to voice sources and remaining small amount is allocated for non real-time data traffic. It is expected that the proposed CAC scheme can well support strict QoS requirements, such as high throughput and low delay at the same time achieve a high channel utilization.

Interference-aware cooperative QoS routing in multi-hop wireless networks

Cooperative communication is a new physical technology, which has the potential to improve QoS support for multi-hop wireless network. Existing works did not consider the interference effect among links while designing cooperative QoS routing. To overcome this limitation, this paper targets at designing an interference-aware Cooperative QoS routing algorithm (CQ-routing) to satisfy users’ bandwidth requirement. We formulate the problem of finding cooperative routing path with maximum available bandwidth as an optimization problem, called Coop-routing problem. We prove that the Coop-routing problem is strong NP-hard. We propose both centralized and distributed algorithm to solve the Coop-routing problem. We prove that the centralized algorithm can achieve a constant approximation ratio. We evaluate the performance of these algorithms through simulations. The results show that CQ-routing algorithms can significantly improve the network performance in terms of available bandwidth and number of admitted flows.

Dynamic spectrum allocation with admission control based on cognitive radio for QoS support in multiple wireless network

Cognitive radio is an emerging technology in wireless access, aimed at vastly improving the way radio spectrum is utilized. In this article, we investigate the performance improvement gained by applying cognitive radio to a multiple wireless service providers (WSPs). We consider several WSPs and two types of users: primary (licensed) and secondary (unlicensed) users. Two different schemes are proposed for unlicensed users to manage their handoff. These two schemes are different in the sense that one allows to each WSP to give more priority to his own unlicensed users by dropping low priority users, while the other does not allow that. The system is modeled by a Markov process, with continuous time and finite state space. Due to the very large number of states, we propose a robust method to approximate the stationary probability distribution vector of Markov process. Based on this approximation, we develop several performance metrics, blocking and dropping probabilities for both kinds of unlicensed users. Numerical results show that this approximation is very close to the exact solution. Finally, we show that spectrum utilization of cognitive users increases with the proposed schemes especially in medium and high traffic.

Examination of Transmission Quality in the IP Multi-Protocol Label Switching Corporate Networks

Abstract The paper presents the examination of quality of transmission designed and built based on IP/MPLS technology as well as BGP and OSPF routing protocols of corporate network. It indicates the factors forming and affecting the service quality in IP network, including QoS support network architecture, particularly the architecture of DiffServ differentiated services. Main problems occurring in these architectures have been discussed. The analysis of data and voice transmission via IP network of Best Effort architecture and in Differentiated Service architecture of differentiated transmission quality have been conducted. It has been presented that the MPLS technology may be effectively applied in building corporate networks requiring network services of highest quality parameters with lossless packet transmission and maximum delay guarantee.

A game-based algorithm for fair bandwidth allocation in Fibre-Wireless access networks

Fibre-Wireless (FiWi) access networks have been proposed as flexible and cost-effective solutions for future access networks. At the wireless mesh section, wireless routers have to forward both local traffic from directly connected users and foreign traffic from neighbour wireless routers. How to allocate resources to local and foreign traffic at each router in a balanced way, while avoiding starvation of routers requiring less resources, is a fundamental issue that must be solved so that new services emerge. Here, we develop a repeated game framework for bandwidth allocation and propose an algorithm that allocates bandwidth in a fair manner. The algorithm is able to detect over claiming routers and avoid possible denial of service that these may cause to others. Moreover, unfruitful use of resource is prevented, avoiding the forwarding of packets that would be dropped at some point later in the path, and queueing delay conditions are kept similar among local and foreign traffic. These fair network conditions open way for QoS support since it is easier to ensure the operationality of services.