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Fiber Wireless (FiWi) provides a solution that combines gigabit passive optical network and Wi-Fi to provide huge capacity as well as mobility support. To manage the bandwidth in FiWi, a dynamic bandwidth allocation is proposed in this paper where it uses time division multiple access at the optical part and Carrier Sense Multiple Access with Collision Avoidance at the wireless part. Two methods are...
In this paper, we address the beacon congestion issue in Vehicular Ad Hoc Networks (VANETs) due to its devastating impact on the performance of ITS applications. The periodic beacon broadcast may consume a large part of the available bandwidth leading to an increasing number of collisions among MAC frames, especially in case of high vehicular density. This will severely affect the performance of the...
In this paper, a differentiated services based congestion control algorithm for Wireless Multimedia Sensor Networks (WMSNs) is proposed. Keeping in mind the characteristics of Wireless Sensor Networks (WSNs) and their possible extensions, the proposed algorithm categorizes WMSNs traffic into six different classes. The algorithm takes a novel and different approach towards congestion control in WMSNs...
Although TCP is one of the key protocols of the Internet infrastructure, it is not optimized for either wireless environment or multimedia streaming applications. It fails to meet the service requirement of streaming applications because of its strict adherence to congestion control. Besides, non-congestion packet loss fools TCP to slow down its sending rate over wireless links. Fast TCP and TCP Westwood+...
This paper introduces a differential transmit reference (DTR) ultra-wideband (UWB) receiver with four receiving antenna arrays for high data rate wireless endoscope applications for real-time transmission of high resolution images. The proposed architecture with an envelope detection scheme is presented and comprehensive system simulation results are used to analyze the receiver performance and derive...
In wireless LAN connected with Internet, the anomaly of wireless channel and the greedy nature of closed loop control in TCP lead to the congestion problem and significant unfair bandwidth distribution between TCP flows. In this paper, an ECN-based access point congestion control algorithm called APCC (AP congestion control) is proposed. The main properties of APCC are: (1) Using both wireless channel...
Recent years have witnessed the pilot deployments of audio or low-rate video wireless sensor networks for a class of mission-critical applications including search and rescue, security surveillance, and disaster management. In this paper, we report the design and implementation of Quality-aware Voice Streaming (QVS) for wireless sensor networks. QVS is built upon SenEar, a new sensor hardware platform...
For industrial applications, real-time performance is a critical issue of wireless sensor network. IEEE802.15.4 protocol has greater potential compared with other protocols. However, it can??t meet the strict requirements of real-time performance in industrial environment. After analyzing the demands of versatile applications in industrial environment and guaranteed time slots (GTS) mechanism in the...
A cross-layer communication protocol called VSN-module is introduced for wireless video sensor networks based on ultrawideband (UWB) radio technology at the physical layer. The core of our solution is a distributed path reservation scheme which routes video traffic from sources (sensors) to a sink. The path establishment takes into account the specific requirements of video flows such as bandwidth,...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
This paper focuses on WiMAX since this wireless technology allows broadband communications. In particular, we provide here a preliminary study on MAC layer performance as well as a sensitivity study to its parameters. A simulation approach has been adopted, based on the ns-2 environment to investigate the impact that real-time traffic has on non-real-time traffic and vice versa. The study presented...
Considering the high packet losses and low, varying bandwidth of GPRS/EDGE network and limited computation power of handheld devices, we present and implement a novel SVC video-on-demand system for hand-held devices over GPRS/EDGE network. For the purpose of handling varying bitrate, we propose a priority based layer switching (PLS) adaptation scheme for SVC stream, which not only performs online...
Wireless multimedia sensor networks (WMSNs) are networks of wirelessly interconnected devices that allow retrieving video and audio streams, still images, and scalar sensor data. WMSN require the sensor network paradigm to be rethought in view of the need for mechanisms to deliver multimedia content with a pre-defined level of quality of service (QoS). In this paper, a new cross-layer communication...
The increasing ubiquity of mobile embedded systems has been matched by the evolution of a variety of wireless network standards and technologies. The major constraints of wireless embedded systems are limitations of communication bandwidth, processing capabilities, and battery power. Remote wireless embedded systems often act as sensors, which provide data to a certain community. The exchange of data...
A scheme that exploits the broadcast nature of the wireless communication in order to achieve multicast content delivery is presented in this paper. As opposed to broadcasting, this method enables the clients to determine on-line the delivered content, and thus preserves the advantages of an individual service. On the other hand, a multicast content delivery is much more efficient than a unicast content...
Expected growth in use and implementation of wireless sensor networks (WSNs) in different environments and for different applications creates new security challenges. In WSNs, a malicious node may initiate incorrect path information, change the contents of data packets, and even hijack one or more genuine network nodes. As the network reliability completely depends on individual nodespsila presence...
Three applications in wireless networks where model-free stochastic learning is applicable, are discussed. The learning based optimization problems are formulated and simulation results are presented. Some open issues are also discussed.
In this paper, we introduce a pricing model that ensures efficient resource allocation that provides guaranteed quality of service while maximizing profit in multiservice networks. Specifically, a dynamic allocation policy is examined that relies on online measurements while each service class operates under a probabilistic bound delay constraint. We present a rigorous analysis of the properties of...
In this paper, we study bandwidth management of a wireless/optical based access/metro network in support of voice and data services. For voice services, we use a finite state Markov Chain to estimate the blocking probability of voice circuits over an Adaptive modulation and coding wireless channel, as a function of the channel parameters. For data services, we evaluate a rate matching and a buffer...
This paper explores the attributes, layering models and objective functions in cross layer designs for mobile ad hoc wireless networks by taking all the statistical characteristics and constraints from the physical (PHY) layer, media access control (MAC) layer and network (NET) layer into consideration. This paper reviews the entire network optimization across all the PHY/MAC/NET layers. At the PHY...
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