QoS provisioning for multimedia wireless networks

As we move towards IP-based multimedia wireless networks with voice, video and data convergence, quality of service (QoS) provisioning will become an increasingly challenging task. One implication is that greater emphasis on managing the call admission and overall network resources will be needed. This paper presents a conservative and adaptive quality of service (CAQoS) framework for provisioning the QoS for both real-time and non-real-time traffic in a multimedia wireless network. Unlike most conventional schemes, which gradually scale down the bandwidth of ongoing connections to accommodate new connection/hand-off requests, CAQoS introduces an early scaling-down of bandwidth for new connections based on a designated provisioning model. The performance of a CAQoS system is evaluated through simulations of a realistic wireless environment. Simulation results show that CAQoS meets our design goals and outperforms conventional schemes.     

5G mobile terminals with advanced QoS-based user-centric aggregation (AQUA) for heterogeneous wireless and mobile networks

In this paper we present an advanced QoS provisioning module with vertical multi-homing framework for future fifth generation (5G) mobile terminals with radio network aggregation capability and traffic load sharing in heterogeneous mobile and wireless environments. The proposed 5G mobile terminal framework is leading to high performance utility networks with high QoS provisioning for any given multimedia service, higher bandwidth utilization and multi-RAT capabilities. It is using vertical multi-homing and virtual QoS routing algorithms within the mobile terminal, that is able to handle simultaneously multiple radio network connections via multiple wireless and mobile network interfaces. Our 5G proposal is user-centric, targeted to always-on connectivity, maximal network utilization, maximal throughput, seamless handovers and performances improvement by using vertical multi-homing, as well as session continuity. The performance of our proposed mobile terminal framework for 5G is evaluated using simulations and analysis with multimedia traffic in heterogeneous mobile and wireless scenarios with coexistence of multiple radio access technologies, such as 3G, 4G as well as future 5G radio access networks.     

Enabling seamless multimedia wireless access through QoS‐based bandwidth adaptation

Effective support of real‐time multimedia applications in wireless access networks, viz. cellular networks and wireless LANs, requires a dynamic bandwidth adaptation framework where the bandwidth of an ongoing call is continuously monitored and adjusted. Since bandwidth is a scarce resource in wireless networking, it needs to be carefully allocated amidst competing connections with different Quality of Service (QoS) requirements. In this paper, we propose a new framework called QoS‐adaptive multimedia wireless access (QoS‐AMWA) for supporting heterogeneous traffic with different QoS requirements in wireless cellular networks. The QoS‐AMWA framework combines the following components: (i) a threshold‐based bandwidth allocation policy that gives priority to handoff calls over new calls and prioritizes between different classes of handoff calls by assigning a threshold to each class, (ii) an efficient threshold‐type connection admission control algorithm, and (iii) a bandwidth adaptation algorithm that dynamically adjusts the bandwidth of an ongoing multimedia call to minimize the number of calls receiving lower bandwidth than the requested. The framework can be modeled as a multi‐dimensional Markov chain, and therefore, a product‐form solution is provided. The QoS metrics—new call blocking probability (NCBP), handoff call dropping probability (HCDB), and degradation probability (DP)—are derived. The analytical results are supported by simulation and show that this work improves the service quality by minimizing the handoff call dropping probability and maintaining the bandwidth utilization efficiently. Copyright © 2006 John Wiley & Sons, Ltd.     

An optimization framework for balancing throughput and fairness in wireless networks with QoS support

Quality-of-service (QoS) provisioning, high system throughput, and fairness assurance are indispensable for heterogeneous traffic in future wireless broadband networks. With limited radio resources, increasing system throughput and maintaining fairness are conflicting performance metrics, leading to a natural tradeoff between these two measures. Balancing system throughput and fairness is desired. In this paper, we consider an interference-limited wireless network, and derive a generic optimization framework to obtain an optimal relationship of system throughput and fairness with QoS support and efficient resource utilization, by introducing the bargaining floor. From the relationship curve, different degrees of performance tradeoff between throughput and fairness can be obtained by choosing different bargaining floors. In addition, our framework facilitates call admission control to effectively guarantee QoS of. multimedia traffic. The solutions of resource allocation obtained from the optimization framework achieve the pareto optimality, demonstrating efficient use of network resources.     

A comprehensive resource management framework for next generation wireless networks

We propose an integrated resource management approach that can be implemented in next generation wireless networks that support multimedia services (data, voice, video, etc.). Specifically, we combine the use of position-assisted and mobility predictive advanced bandwidth reservation with a call admission control and bandwidth reconfiguration strategy to support flexible QoS management. We also introduce a mobile agent based framework that can be used to carry out the functions of geolocation and of the proposed resource management in wireless networks. A model is also developed to obtain the optimal location information update interval in order to minimize the total cost of the system operation. The comparison of the achievable performance results of our proposed scheme with the corresponding results of a conventional system that supports advanced bandwidth reservation only, as means of supporting the QoS requirements, demonstrate that our integrated scheme can alleviate the problem of overreservation, support seamless operation throughout the wireless network, and increase significantly the system capacity.     

Secure group communication in wireless mesh networks

Wireless mesh networks (WMNs) have emerged as a promising technology that offers low-cost community wireless services. The community-oriented nature of WMNs facilitates group applications, such as webcast, distance learning, online gaming, video conferencing, and multimedia broadcasting. Security is critical for the deployment of these services. Previous work focused primarily on MAC and routing protocol security, while application-level security has received relatively little attention. In this paper we focus on providing data confidentiality for group communication in WMNs. Compared to other network environments, WMNs present new challenges and opportunities in designing such protocols. We propose a new protocol framework, Secure Group Overlay Multicast (SeGrOM), that employs decentralized group membership, promotes localized communication, and leverages the wireless broadcast nature to achieve efficient and secure group communication. We analyze the performance and discuss the security properties of our protocols. We demonstrate through simulations that our protocols provide good performance and incur a significantly smaller overhead than a baseline centralized protocol optimized for WMNs.     

Routing Protocol for Heterogeneous Hierarchical Wireless Multimedia Sensor Networks

Recently, wireless multimedia sensor networks (WMSNs) have emerged as one of the most important technologies, driven by the development of powerful multimedia device such as CMOS. WMSNs require several factors such as resource constraints, specific QoS, high bandwidth and so on. In this paper, we propose a hierarchical heterogeneous network model based routing protocol for WMSNs. In our proposal, proposed network model is classified into monitoring class, delivery class and aggregation class. Also we define two kinds of the routing path in order to ensure bandwidth and QoS. In simulation results, we illustrate the performance of our proposal.     

Dynamic-Grouping bandwidth reservation scheme for multimedia wireless networks

In wireless networks carrying multimedia traffic (voice, video, data, and image), it becomes necessary to provide a quality-of-service(QoS) guarantee for multimedia traffic connections supported by the network. In order to provide mobile hosts with high QoS in the next-generation wireless networks, efficient and better bandwidth reservation schemes must be designed. This paper presents a novel dynamic-grouping bandwidth reservation scheme as a solution to support QoS guarantees in the next-generation wireless networks. The proposed scheme is based on the probabilistic resource estimation to provide QoS guarantees for multimedia traffic in wireless cellular networks. We establish several reservation time sections, called groups, according to the mobility information of mobile hosts of each base station. The amount of reserved bandwidth for each base station is dynamically adjusted for each reservation group. We use the dynamic-grouping bandwidth reservation scheme to reduce the connection blocking rate and connection dropping rate, while increasing the bandwidth utilization. The simulation results show that the dynamic-grouping bandwidth reservation scheme provides less connection-blocking rate and less connection-dropping rate and achieves high bandwidth utilization.     

SIP Multicast-Based Mobile Quality-of-Service Support over Heterogeneous IP Multimedia Subsystems

The Universal Mobile Telecommunications System (UMTS) all-IP network supports IP multimedia services through the IP Multimedia Subsystem (IMS). This paper proposes a mobile Quality-of-Service (QoS) framework for heterogeneous IMS interworking. To reduce the handoff disruption time, this framework supports the IMS mobility based on the concept of Session Initiation Protocol (SIP) multicast. In our approach, the mobility of a User Equipment (UE) is modeled as a transition in the multicast group membership. With the concept of dynamic shifting of the multicast group's members, the flow of actual data packets can be switched to the new route as quickly as possible. To overcome mobility impact on service guarantees, UEs need to make QoS resource reservations in advance at neighboring IMS networks, where they may visit during the lifetime of the ongoing sessions. These locations become the leaves of the multicast tree in our approach. To obtain more efficient use of the scarce wireless bandwidth, our approach allows UEs to temporarily exploit the inactive bandwidths reserved by other UEs in the current IMS/access network. Analytic and simulation models are developed to investigate our resource reservation scheme. The results indicate that our scheme yields comparable performance to that of the previously proposed channel assignment schemes.     

QoS Provisioning in Wireless/Mobile Multimedia Networks Using an Adaptive Framework

Recently there is a growing interest in the adaptive multimedia networking where the bandwidth of an ongoing multimedia call can be dynamically adjusted. In the wireless/mobile multimedia networks using the adaptive framework, the existing QoS provisioning focused on the call blocking probability and the forced termination probability should be modified. We, therefore, redefine a QoS parameter – the cell overload probability – from the viewpoint of the adaptive multimedia networking. Then, we propose a distributed call admission control (CAC) algorithm that guarantees the upper bound of the cell overload probability. Also, a bandwidth adaptation algorithm which seeks to minimize the cell overload probability is also presented. Simulation experiments are carried out to verify the performance of the proposed CAC algorithm. Furthermore, the performance of the adaptive wireless/mobile network is compared to that of the existing non-adaptive wireless/mobile networks. As a further step in QoS provisioning, we propose another QoS parameter, the degradation period ratio, and discuss analytically how the CAC algorithm guarantees the upper bound of the degradation period ratio.     

A QoS-aware routing mechanism for multi-channel multi-interface ad-hoc networks

To accommodate real-time multimedia application while satisfying application QoS requirements in a wireless ad-hoc network, we need QoS control mechanisms. In this paper, we propose a new routing mechanism to support real-time multimedia communication by efficiently utilize the limited wireless network capacity. Our mechanism considers a wireless ad-hoc network composed of nodes equipped with multiple network interfaces to each of which a different wireless channel can be assigned. By embedding information about channel usage in control messages of OLSRv2, each node obtains a view of topology and bandwidth information of the whole network. Based on the obtained information, a source node determines a logical path with the maximum available bandwidth to satisfy application QoS requirements. Through simulation experiments, we confirmed that our proposal effectively routed multimedia packets over a logical path avoiding congested links. As a result, the load on a network is well distributed and the network can accommodate more sessions than QOLSR. We also conducted practical experiments using wireless ad-hoc relay nodes with four network interfaces and verified the practicality of our proposal.     

嵌入式平台下的安全媒体传输系统

Security video communication is a challenging task, especially for wireless video applications. An efficient security multimedia system on embedded platform is designed. By analyzing the hardware architecture and resource, the efficient DSP-based H.264/AVC coding is studied by efficient video coding techniques and system optimizing implementation.To protect the confidentiality and integrity of media information, a novel security mechanism is presented, which includes user identify authentication and a perceptual video encryption algorithm based on exploiting the special feature of entropy coding in H.264. Experimental results show that the proposed hardware framework has high performance and achieves a better balance between security and efficiency. The proposed security mechanism can achieve high security and low complexity cost, and has a little effect on the compression ratio and transmission bandwidth. What’s more, encoding and encryption at the same time, the performance of data process can meet real-time application.     

An adaptive bandwidth reservation scheme for high-speed multimediawireless networks

In the next generation high-speed wireless networks, it is important to provide quality-of-service (QoS) guarantees as they are expected to support multimedia applications. This paper proposes an admission control scheme based on adaptive bandwidth reservation to provide QoS guarantees for multimedia traffic carried in high-speed wireless cellular networks. The proposed scheme allocates bandwidth to a connection in the cell where the connection request originates and reserves bandwidth in all neighboring cells. When a user moves to a new cell and a handoff occurs, bandwidth is allocated in the new cell, bandwidth is reserved in the new cell's neighboring cells, and reserved bandwidth in more distant cells is released. The amount of bandwidth to reserve is dynamically adjusted, reflecting the current network conditions. The performance of the proposed scheme is evaluated through simulations of realistic cellular environments. The simulated network consists of a large number of cells, mobile users with various movement patterns are assumed, and a variety of multimedia applications (e.g., audio phone, video conference, video on demand, file transfer, etc.) is considered. It is shown that the proposed scheme provides small handoff dropping probability (i.e., the probability that handoff connections are dropped due to a lack of bandwidth) and achieves high bandwidth utilization     

Efficient cross-layer protocol for bandwidth-satisfied multicast in multi-rate MANETs

Since the multi-rate enhancements have been implemented in 802.11 wireless networks, QoS-constrained multicast protocols for multimedia communication should be adapted to exploit them fully. This work proposes a multicast protocol for data rate selection and bandwidth-satisfied multicast tree determination with an efficient cross-layer design based on the integration of PHY and MAC layers into the network layer. To use bandwidth efficiently and increase network capacity (which is the number of multicast flows supported by the network), we aim to select the combination of data rates and a multicast tree whose total amount of bandwidth consumption to the network is minimal in order to maximize the network capacity. The performance of the proposed protocol is compared with two existing protocols. Simulation results indicate that the proposed protocol has the ability to admit more multicast flows.     

Adaptive online processor management algorithms for multimedia data communication with QoS sensitivity

Energy consumption has become an increasingly important consideration in many real‐time systems. Therefore, the design and analysis for energy‐efficient processor management techniques is an important and widely open research field. In this paper, I propose new online processor management algorithms to control heterogeneous multimedia services while maximizing energy efficiency. These online management algorithms—quality of service control, service request admission and scheduling algorithms—are combined in an integrated framework for higher system performance and energy efficiency. The most important feature of my proposed online framework is its adaptability, flexibility, and responsiveness to current system conditions. Simulation results clearly indicate the superior performance of my proposed framework to strike the appropriate performance balance between contradictory requirements. Copyright © 2008 John Wiley & Sons, Ltd.     

Piecewise Network Awareness Service for Wireless/Mobile Pervasive Computing

This paper presents a piecewise framework for network awareness service (NAS) for wireless/mobile pervasive computing. We investigate how piecewise consideration of wired and wireless elements of the framework architecture benefits service advertisement and discovery and network-awareness techniques. We also discuss scalability of the NAS framework with respect to platform computing capabilities. The framework is suitable for a wide range of computing devices, from powerful ones with multi-tasking operating systems (OS) to small ones with lightweight OS. Case studies applying the NAS framework to sensor monitoring in home networks and data streaming in pervasive multimedia computing are presented. The analytical results on the performance of the NAS framework in these case studies show that it has significant advantages over traditional network-awareness frameworks in terms of reducing wireless bandwidth consumption and saving battery energy of mobile devices.     

Performance of Transport Protocols for Multimedia Communications in Wireless Sensor Networks

Many wireless sensor network (WSN) applications require efficient multimedia communication capabilities. However, the existing communication protocols in the literature mainly aim to achieve energy efficiency and reliability objectives and do not address multimedia communication challenges in WSN. In this paper, comprehensive performance evaluation of the existing transport protocols is performed for multimedia communication in WSN. Performance metrics such as packet delivery rate, end-to-end packet delay, bandwidth and energy efficiency, frame peak signal-to-noise ratio (PSNR), delay-bounded frame PSNR, frame delivery probability, frame end-to-end delay and jitter are investigated. The results clearly show that the existing transport protocols are far from satisfying the requirements of multimedia communication in WSN and hence there is a need for new effective multimedia delivery protocols for WSN.     

An Architecture for Service Quality Management Using Cooperative Communications

The rapid enhancement and explosive expansion of mobile communication systems will lead to an increased demand for multimedia services. Various multimedia contents will be available due to the proliferation of IPTV, video on demand, user-generated content, and content-centric networking. Therefore, multimedia service quality is becoming a critical issue. The static allocation of network resources may not be sufficient to guarantee the required service quality of multimedia in wireless networks. For ensuring the service quality, it is important to manage the resources considering the overall performance of the network and the end system. In particular, a certain level of service quality should be maintained regardless of the network situation. To achieve this objective, we first propose an architecture for service quality management and then present a detailed framework and mechanisms to maintain the desired service quality using the cooperation between communication entities in wireless networks. Simulation results are also presented to show that the proposed framework works well in wireless networks.     

Reducing Channel Capacity for Scalable Video Coding in a Distributed Network

In recent years, the development of multimedia devices has meant that a wider multimedia streaming service can be supported, and there are now many ways in which TV channels can communicate with different terminals. Generally, scalable video streaming is known to provide more efficient channel capacity than simulcast video streaming. Simulcast video streaming requires a large network bandwidth for all resolutions, but scalable video streaming needs only one flow for all resolutions. In previous research, scalable video streaming has been compared with simulcast video streaming for network channel capacity, in two user simulation environments. The simulation results show that the channel capacity of SVC is 16% to 20% smaller than AVC, but scalable video streaming is not efficient because of the limit of the present network framework. In this paper, we propose a new network framework with an SVC extractor. The proposed network framework shows a channel capacity 50% (maximum) lower than that found in previous research studies.     

Collaborative Distributed Admission Control (CDAC) for Wireless Ad Hoc Networks

Admission control algorithms have been widely researched for many years to guarantee the Quality of Service (QoS) for multimedia applications over the wired Internet. With the recent surge of wireless home networks, it is increasingly important to employ the admission control mechanisms in order to enhance the performance of the wireless multimedia applications. In this paper, we propose a framework for performing distributed admission control in a collaborative wireless environment. In particular, a wireless device will not inject a new flow into the wireless medium if it determines that by doing so, there is not enough resources to support all the existing flows. Our contributions are threefold. First, we propose a modification to 802.11x based network in order to increase the bandwidth efficiency. Specifically, doubling the contention window (CW) size after a collision is no longer necessary in the proposed wireless network. Second, we provide a performance analysis for the modified 802.11x based wireless networks with multiple flows having different throughput requirements. Third, using the theoretical analysis, we propose two distributed admission control algorithms based on the transmission opportunity (TXOP) and the CW. Simulation results confirm our theoretical predictions on the performance of the proposed admission control algorithms.