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The heterogeneous multicast networks are the networks with several wireless technologies that provide multicast service. Due to the high data rate of the service, point-to-point (P2P) transmission mode, which is employed by unicast channels, is no longer the best mode because of its inefficiency in power consumption and spectrum utilization. Compared with P2P, point-to-multipoint (P2M) transmission...
Many modern wireless data networks employ Carrier Sense Multiple Access (CSMA) for efficient medium access. The p-persistent CSMA protocol is an analytically tractable version of CSMA that has been used successfully to model practical medium access protocols such as the IEEE 802.11 Distributed Coordination Function (DCF). We present a closed-form expression to characterize the access probabilities...
This paper addresses the problem of MAC performance evaluation of a contemporary IEEE 802.11 WLAN. The network is observed under saturation conditions and the packet transmission probability analysis is conducted with the novel regenerative approach. The proposed model accounts for collision resolution protocol parameters, packet retry limit, coexistence of unicast and broadcast traffic, and heterogeneous...
The performance of the IEEE 802.11 protocol based on the distributed coordination function (DCF) depends on the number of competing terminals. We propose game theory-based extended H∞ filter approach to the problem of estimating the number of competing terminals. The proposed approach has an advantageous feature that the noise information of the dynamic state system and the measurement equation is...
Representation of indoor 3D location tracking had been an advantage to globally supported to track the mobile unit everywhere, even in different level of building. Our main focus is presenting development of indoor 3D location tracking to replace the existing 2D location tracking. The 2D location tracking mechanism only supports tracking the mobile unit position in the same level and provides handover...
Group-polling based schemes for the enhancement of the Point Coordination Function (PCF) in the 802.11 have been supposed to be the most efficient scheme for the transmission of VoIP frame. However, most of the group-polling schemes are not energy-efficient at all due to the fact that all the stations in this list must listen to the channel during all the transmissions belonging to this polling list...
This paper introduces control systems, which regulate tranceivers' packet sizes for prevailing network conditions to achieve maximum throughput and minimum delay for real-time traffic in Wireless Local Area Networks (WLANs). Delay and throughput are very much dependent on the packet size and the connection density. Therefore, the selected input parameters for the controllers are one-way delay and...
The ability to measure location using time of flight in 802.11 networks is impeded by the standard one microsecond clock resolution, imprecise synchronization of the 802.11 protocol, and the inaccuracy of available clock oscillators. We demonstrate a technique for off-the-shelf 802.11 hardware that enables accurate determination of location of transmitting 802.11 devices using time difference of arrival...
As the era of ubiquitous computing dawns, there is a growing need for a reliable, efficient positioning and tracking system. A localization system involves ongoing tracking of the location of assets and personnel. This paper presents a practical localization system for consumer devices on Zigbee networks. The proposed system is based on time-difference-of-arrival (TDOA). Localization based on TDOA...
In WiFi networks, mobile nodes compete for accessing a shared channel by means of a random access protocol called Distributed Coordination Function (DCF). Although this protocol is in principle fair, since all the stations have the same probability to transmit on the channel, it has been shown that unfair behaviors may emerge in actual networking scenarios. Assuming that a contending node can dynamically...
IEEE 802.16e standard for mobile Worldwide Interoperability for Microwave Access (WiMAX), defines the implementation of hard handover. The standard covers the physical and MAC layer. To apply the layer 3 (L3) handover protocol over the existing IEEE 802.16e layer 2 (L2) handover scheme, the fast mobile IPv6 was used by many researches, but long latency is main challenge for real-time applications...
Transport Control Protocol (TCP), the mostly used transport protocol, performs well over wired networks. As much as wireless network is deployed, TCP should be modified to work for both wired and wireless networks. Since TCP is designed for congestion control in wired networks, it cannot clearly detect non-congestion related packet loss from wireless networks. TCP-Westwood presents one solution to...
The paper describes the necessary fields investigated for creating an application that is able to monitor any kind of network, wired or wireless, with all its possible aspects. In the same application, we also implemented original algorithms for finding the position of a moving station, utilizing the signal level of the wireless protocols 802.11 devices (Wi-Fi). Field research and exhausting sampling...
Cooperative collision warning system for road vehicles, enabled by recent advances in positioning systems and wireless communication technologies, can potentially reduce traffic accident significantly. To improve the system, we propose a graph model to represent interactions between multiple road vehicles in a specific region and at a specific time. Given a list of vehicles in vicinity, we can generate...
Media access protocols in wireless networks require each contending node to wait for a backoff time chosen randomly from a fixed range, before attempting to transmit on a shared channel. However, nodes acting in their own selfish interest may not follow the protocol. In this paper, we use a game-theoretic approach to study how nodes might be induced to adhere to the protocol. In particular, a static...
In this paper we propose a novel method for associating Wireless Mobile Nodes (WMNs) to Access Points (APs) in busy wireless access networks. The proposed method associates each WMN with multiple APs for mitigating the load balancing problem in hot-spots. The method assumes that a concurrent multipath transport control protocol such as cmpTCP is used at the end-points. The connections are established...
Analytical models of IEEE 802.11-based WLANs are invariably based on approximations, such as the well-known mean-field approximations proposed by Bianchi for saturated nodes. In this paper, we provide a new approach for modeling the situation when the nodes are not saturated. We study a State Dependent Attempt Rate (SDAR) approximation to model M queues (one queue per node) served by the CSMA/CA protocol...
The traditional security enforcement approach of network is employing cryptography and authentication scheme. However, we consider that the conventional view of security based on cryptography alone is not sufficient for the wireless LAN and Third-generation (3G) integration networks against malicious or non-malicious insertion of data from internal adversaries or faulty nodes. In this paper, we propose...
Collisions, sudden fades, and wireless channel errors are a significant source of packet loss in wireless LANs. However, higher level protocols typically have no way to determine the cause of packet loss, and generally make assumptions about the source of packet failure that may be incorrect. Accurate information about the source of packet loss could be valuable information to an upper layer. In addition,...
In this paper we propose a combined MAC protocol for wireless ad hoc networks that overcome some of the limitations of basic IEEE 802.11b MAC protocol. The proposed protocol involves the concept of cooperation along with persistence to avoid the negative effects caused by multi rate modulation employed by the 802.11b. Unlike basic MAC protocol, the proposed MAC also provides service distinction to...
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