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Multimedia communication over wireless networks has become the driving technology for many important applications, experiencing dramatic market growth and promising revolutionary experiences in personal communication, gaming, entertainment, military, security, environment monitoring, and more. The advances in wireless communications and growth of real-time applications have necessitated the development...
In this paper, we explore the use of directional antennas in relay transmission to improve the performance of video multicast with omni-directional relays in infrastructure- based wireless networks. We describe the system setup with directional relays and determine the user partition along with transmission time scheduling that can optimize a multicast performance criterion. We demonstrate that directional...
To improve the JPEG2000 compression standard error resiliency in the wireless environment, the use of ternary MQ arithmetic coders/decoders that are based on the concept of forbidden symbol has been proposed. This paper presents two ternary MQ based techniques to reduce both the computational complexity and the memory requirement during the decoding process, with no or little degradation in the PSNR.
Cross-layer optimization aims at improving the performance of network users operating in a time-varying, error-prone wireless environment. However, current solutions often rely on ad-hoc optimization approaches, which ignore the different environmental dynamics experienced at various layers by a user and violate the layered network architecture of the protocol stack. This paper presents a new theoretic...
In this paper, we design an admission control scheme for ad hoc WLAN based on self-restraint mechanism. The self-restraint admission control mechanism is implemented in each of the wireless nodes instead of the access point (AP). It has two important admission control abilities: first, it can restrain itself from joining the network if the network channel is congested; second, a joining node can drop...
The following topics are dealt with: communication theory; signal processing; wireless communication; optical technology; sensor networks; ad hoc networks; multimedia communications; antenna propagation; microwave engineering; applied electronics.
Supporting multimedia applications over mobile ad hoc networks is a challenging issue. This paper proposes a Position-based Multipath Routing Protocol (PMRP) for real-time multimedia streaming in mobile ad hoc networks. We present an alternative path selection strategy to alleviate packet loss when primary route breaks. On the other hand, two different flood schemes are deployed in the process of...
In ad hoc networks, the end-to-end delay of packets becomes long when other middle nodes transmit these packets and the multi-hops will affect the quality-of-service (QoS) of voice and video. This paper analyzes influence of multi-hops in ad hoc network by a simulative experiment, which put forward an improved access algorithm, called as more hop first-EDCF (MHF-EDCF). The mechanisms are based on...
Satellite-based telecom systems provide the best and quickest solution to reducing the digital divide in less-favored areas owing to their wide geographical coverage and the speed and ease of deployment of terminal equipment. However, satellite system must be efficient and cost effective, and capable of full inter-working with state-of-the-art terrestrial broadband networks. This paper presents a...
The following topics are dealt with: next generation mobile applications; IP multimedia system enhancement; QoS mechanism; peer to peer network; energy consumption; location techniques; next generation network mobility; content sharing; service composition; context aware services; m-learning; m-commerce; cellular networks; propagation and antennas; ad hoc networks; WiMax; multimedia network; wireless...
With the extensive growth of the Internet, wireless technology, and multimedia applications, quality of service (QoS) monitoring and measurement of the networks have become important. Network measurements are carried out to obtain information about important QoS parameters such as delay, loss and jitter. Each type of multimedia applications has its own requirements and limits on these parameters....
Multimedia Broadcast/Multicast Service (MBMS) allows a common broadcast channel to be shared by users interested in identical content. We explore the problem of enhancing MBMS resilience by repairing packets lost during broadcast. Since MBMS broadcast consumes expensive 3G resources, we leverage the ubiquity of multi-homed mobile devices i.e., devices having both cellular and IEEE 802.11 wireless...
Wireless ad hoc networks are characterized by frequent topology changes, unreliable wireless channel, network congestion and resource contention. Multimedia applications usually are bandwidth hungry with stringent delay, jitter and loss requirements. Designing ad hoc networks which support multimedia applications, hence, is considered a hard task. In this paper, we report our work on supporting video...
Real-time multimedia transport has stringent bandwidth, delay, and loss requirements. It is a great challenge to support such applications in wireless ad hoc networks, which are characterized by frequent link failures and congestion. Using multiple paths in parallel for a real-time multimedia session (called multipath transport) provides a new degree of freedom in designing robust multimedia transport...
As the growth of multimedia communications involving digital audio and video, it is increasingly important for the MANET (mobile ad hoc network) routing protocols to simultaneously support both real-time and non-real-time traffic. MANET energy management should offer this support because devices are equipped with limited battery power. To achieve this end, we revise the ad hoc on-demand distance vector...
Supporting high-speed multimedia services is the greatest challenge for next generation cellular networks. Several techniques and solutions have been proposed in response to increasing demands of users. Among them, multihop cellular network (MCN) is one of the promising solutions. MCN architecture aims to incorporate the flexibility of ad hoc networks into traditional cellular networks. In this paper,...
With the increase of multimedia traffic over the past few years and traffic differentiation introduced by IEEE 802.11e, nodes with delay-sensitive multimedia traffic tend to be busy for long periods, thus exacerbating the congestion problem in mobile ad hoc networks (MANETs). Although most of the existing routing protocols are based on the shortest path algorithm, some other metrics like load and...
Supporting real-time data transport in highly dynamic conditions, which arise in wireless and mobile ad hoc networks is challenging. The significant variations in link bandwidth and latency undermine the quality of real-time applications by introducing congestion and delay jitters. For such applications data is only useful before its lifetime expires. In this paper we investigate a staleness-aware...
In mobile ad hoc networks, the communication node always produces a great deal of routing control packets while performing the route discovery and maintenance, which seriously impacts the real-time video transmission quality. Therefore, we propose a new routing control packets limited forwarding (RCPLF) algorithm that can reduce the routing overhead of on-demand routing protocol. In our algorithm,...
In ad hoc networks, the end-to-end delay of a packet will become very great if the packet was forward by many middle nodes, which has a great influence to the QoS of multi-media traffic. We improve the 802.11e EDCF mechanism by introduce the hops of a packet into EDCF as a parameter based on the multi-hop characteristic of Ad Hoc networks with cross-layer method. The result of our simulations show...
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