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In the field of telecommunications, mobility represents new practical ways of communication that are known to be vaguely flexible in terms of use; for users expect to enjoy constant and good quality service. An attempt will be make; all along this file; to introduce the concept of Multihoming to mobile networks in order to increase their strength and resistance toward the effects of mobility, along...
To cater for different conditions of QoS application, this paper proposes an adaptive cross-layer QoS model for mobile Ad Hoc networks according to their characteristics. Based on the traditional TCP/IP protocol stack, the cross-layer information exchange module and the adaptive decision-making module are added. The cross-layer information exchange module breaks the restriction of the original layer...
The following topics are dealt with: tree-building algorithms; HCM decision tree; grid authorization system; grid scheduling system; evolutionary algorithm; data allocation problem; read-one-write-all monitoring synchronization transaction system; large block FEC; RED queue; TFRC congestion control; TCP; mobile ad hoc networks; vehicular ad hoc networks; wireless sensor networks; failure route protocol;...
This paper describes an approach to detect Quality of Service degradation due to packet congestion within wireless networks. The proposed approach can assist management systems to detect a degradation based on easy determinable packet metrics. Metrics like interface queue length, round trip times and retry ratio are evaluated regarding thresholds and detection performance. With a combination of metrics,...
Advanced wireless networking technologies are expected to assist a human life comfortably. In this scenario, high quality real-time communication is important. This paper proposes a novel User Datagram Protocol (UDP) with rate-based congestion control to achieve Quality of Service (QoS) in wireless Ad-Hoc network.
TCP, the facto standard used in today's Internet, has been found to perform poorly in Mobile Ad Hoc Networks (MANETs). This is exacerbated by contention with increasing UDP-based high priority multimedia traffic and the class differentiation introduced in current QoS protocols, which results into TCP starvation and increased spurious timeouts. In this paper, we propose a cross-layer TCP enhancement...
To enable seamless integration of ad hoc networks with other Infrastructure LANs and to the Internet, TCP seems to be the natural choice for users of ad hoc networks that want to communicate reliably with each other and with the Internet. It is well-known that due to the nature of multi-hop wireless Ad hoc network applications, TCP throughput instability can have a devastating impact on the QoS requirements...
The ability to provide various application services introduces more traffic and therefore the problem of data traffic congestion in a VANET (Vehicular Ad-Hoc Network), and hence the QoS (Quality of Service) of the application deteriorates. This paper studies an adaptive PI rate-controller to improve/restore the QoS. The controller controls the source sending rate based on the instantaneous queue length...
The following topics are dealt with: mobility management; ad hoc networks; routing protocol; resource allocation; cooperative relay MIMO systems; adjacent channel interference cancellation; MANETs; LDPC codes; frequency selective fading channels; mobile services; mobile telemedicine; TCP; public key; time frequency division multiplex; RF front-ends design; asynchronous DS-CDMA; indoor tracking algorithm;...
For the limitation of the network resources, to support real-time service in mobile ad hoc networks is challenging, especially for the delay sensitive voice sessions. Firstly, the delay spike phenomenon is described and analyzed in detail in this paper. Then, to alleviate its impairment on the voice quality, based on the prediction of delay spikes, a new source rate adjusting mechanism is proposed,...
The dynamic composition of systems of networked appliances, or virtual devices, in MANETs, enables users to generate, on-the-fly, complex strong specific systems. Current work in the development of service composition architectures in MANETs has yet to address QoS metrics for enhanced composition from a virtual device perspective. In this paper, we present an extension to a prominent dynamic broker-based...
As the rapid growth of multimedia communication demand, it is inevitable to develop a method that could convey multimedia applications on IP network that is previously a text-based communication. In this research, we implement and investigate the H.264 and MPEG-4 video codec, as well as the quality of their transport over wireless environment, particularly mobile IPv4 and adhoc networks. Video quality...
As wireless local area networks (WLAN) become ubiquitous and an integral part of data networks, they will also be increasingly used for applications ranging from standard Internet services like ftp to time bound multimedia applications, such as Voice (or Video) over IP (VoIP/VIP), HDTV etc. with strict latency, throughput or jitter restrictions. These applications on WLAN will also be more bandwidth...
Communication in VANETS needs consideration of high mobility, congestion, collision and reliability factors. The successful delivery of important messages needs high reliability in case of TCP traffic during high congestion. Reliability and performance of priority based traffic is better than for same priority traffic and produces different results. In this paper we have analyzed the performance of...
It is well-known that TCP has difficulty in achieving desirable levels of performance in multi-hop ad hoc networks. TCP implements a loss-based congestion control mechanism for adjusting traffic in the networks. However, when TCP reacts to a loss event in a multi-hop ad hoc network, contentions raised in the IEEE 802.11 MAC layer among nodes usually becomes excessive. This problem eventually induces...
The presence of delay-sensitive traffic in QoS-aware MANETs (mobile ad-hoc networks) results into increased TCP spurious timeouts, thus wasting their scarce bandwidth. Furthermore, the different dynamics used by a routing protocol in discovering and maintaining routes have a significant impact on TCP and MANETs in general. In this paper, we investigate the combined effect of contention- induced spurious...
The bandwidth is one of the most precious resources in mobile ad hoc networks (MANETs); their network protocols should therefore be able to achieve an increase in efficiency of bandwidth utilization. TCP, which implements flow control to regulate the network traffic, plays a significant role in determining the workload of the network. However, spurious TCP retransmissions can increase the link utilization...
WiMedia UWB platform consists of two specifications; WiMedia MAC and PHY. WiMedia MAC may give support to allow industry protocol applications to share UWB resource. Actually, in addition to certified wireless USB, wireless 1394 and TCP/IP, many other industry protocols can reside on top of the WiMedia UWB platform. Thus the mechanism to decide medium access time between them is very important to...
The following topics are dealt with: communications QoS, reliability and performance modelling; wireless mesh, ad hoc and cellular networks; network routing; network congestion control; QoS control in mobile networks; wireless local area networks; network recovery and protection; network resource management; network traffic engineering; QoS techniques for video and voice; LDPC codes; cooperative networks;...
The following topics are dealt with: ubiquitous computing; wireless ad hoc network security; quality of service; TCP/IP; mobility and topology management.
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