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In this paper, we present Localized Tree Change Multicast Protocol (LTMP), a novel source based multicast protocol for Mobile Ad Hoc Networks with the underlying theme being that a forwarding group is maintained by enabling a forwarding flag at each of the nodes without the need to periodically flood the network with the membership status of the group nodes. LTMP also provides end-to-end signaling...
In recent years, a variety of new routing protocols have been developed in order to increase the performance of ad hoc mobile networks. Each protocol more or less based on different strategy. TCP which basically designed for wireline networks faces difficulties in ad hoc wireless networks. In this paper we analyze the performance of well-known protocols under most known TCP versions with two widely...
The cellular world and the Internet, the two standard communication mediums in use today, is converging through the IP Multimedia Subsystem. This creates the opportunity to develop innovative and powerful services that increase the productivity of communications. Maintaining user privacy is a primary factor that should be kept in mind when creating such services. In this paper the authors propose...
Because of the heterogeneity in radio transceiver capabilities and influence of surroundings, unidirectional links arise in wireless mobile ad-hoc networks. Since most of existing routing protocols for MANETs assume that all links are bidirectional, they would fail in establishing a path or cannot prepare sufficient number of paths for the purpose of multipath routing in a network with unidirectional...
The IEEE 802.11e is a new standard to support QoS in Wireless LAN (WLAN). A concept called transmission opportunity (TXOP) has been proposed in 802.11e to confine the maximum time duration that a station can be allowed to retain the channel after winning a contention or receiving a QoSpoll from the QAP. Multiple frames can be transmitted within one acquired TXOP without any additional contention or...
Efficient medium access control (MAC) protocol plays a critical role in wireless mobile networks. In this paper, we propose a rate adaptive hybrid MAC (RAH-MAC) protocol to support differential services in wireless cellular networks. RAH-MAC is a hybrid of polling and contention MAC protocol. In RAH-MAC, when a mobile terminal (MT) has data to send, it first uses the contention time slot to join the...
In this paper, the Doppler shift of the time-varying multi-path channel is estimated by calculating the expectation of the ACF (Auto-Correlation Function) of the channel coefficient estimates on the effective fingers. Furthermore we analyze the estimation bias and propose an improved estimation method based on SNR (Signal-to-Noise Ratio) estimation to obtain the high estimation accuracy in wide ranges...
In recent years, the advances in the development and manufacture techniques have allowed the appearance of small-sized, low-cost and low-power consumption sensors, which are grouped forming wireless sensor networks (WSNs). These networks have application in fields such as military, health or scientific. One critical point in these applications is the time synchronization among the sensors, which helps...
To achieve scalable wireless design utilizing Ultra- Wide-Band (UWB), cognitive radio, and hybrid network (ad-hoc with infrastructure such as AP, access point), we propose a cooperative interference adaptation method, where a node by sensing the frequency spectrum, can adapt its transmit power to maximize its throughput capacity under the aggregate interference constraint. By developing an AP-assisted...
Geographic routing in wireless sensor networks is based on the prerequisite that every node has information about its current position, for instance via GPS or some localization algorithm. This location information has a certain degree of inaccuracy in real deployments. The majority of geographic routing algorithms, however, has been designed for nodes with exact position information. We show that...
In many radio propagation environments, a Line of Sight (LoS) component exists between the transmitter and the receiver. This way the time-varying envelope of the received signal can be described by a Rician distribution with Rician factor K. Therefore, precise and efficient methods of Rician K factor estimation are of substantial concern. In this paper we examine a Rician K factor estimator suitable...
A new gradient approach to adaptive subspacebased frequency estimation of multiple real valued sine waves is considered in this paper. Authors proposed in [2] a novel combination of strong adaptive covariance matrix update and optimized block processing for frequency values retrieval of sinusoidal carriers. The new approach proposed here combines the gradient subspace tracking technique based on Oja...
The innovation of mobile communications is driving the emergence of new and exciting services. Some killer applications, such as 3GPP streaming service, need a functionality of mobile terminal capability exchange for services enabling, which requires a mechanism to manage terminal capabilities. This paper presents the Mobile Terminal Capability Management (MTCM) architecture allowing to collect, update,...
Nowadays the people can manage their contacts or calendars easily between their various mobile devices and the network server by Data Synchronization service. But the same important personal information such as short messages can not be managed. In this paper, a novel method for the short message or multimedia message synchronization is presented to solve this problem using the SyncML (Synchronization...
This paper deals with bit-interleaved coded modulation (BICM) using M-ary orthogonal signaling. Simplified algorithms for the soft-output bit demapper for coherent and noncoherent M-FSK are developed, resulting in low complexity implementation. A performance comparison between BICM systems employing M-FSK modulation in AWGN and Rayleigh flat fading channels is presented, considering exact and approximate...
Channel estimation techniques for CDMA systems need to combat multiple access interference and near-far effects to improve the estimation performance. Linear singleuser MMSE detector has certain advantages with respect to near-far problem. In this paper, single-user MMSE detector is used to develop an iterative near-far resistant radio channel estimation algorithm. Computer simulation results demonstrate...
All the proposed IP mobility protocols assume that the mobile nodes always have a mobility-aware IP stack. On the other hand, efficient micro-mobility solutions entail specific topologies and mobile-aware routers, requiring major changes in the existing infra-structures. Major advantages are foreseen if mobility can be supported using the existing legacy infra-structure, on both client and network...
Recently there is a growing interest in the Internet and multimedia wireless networking where the bandwidth and the QoS (Quality of Service) metrics must be profoundly adjusted to the application requirements. However the problem of user bandwidth availability arises as one of the most limit of this solution. In fact, the IEEE 802.11 standards do not provide performed mechanism of loading distribution...
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