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The current Medium Access Control (MAC) protocol of the Wireless Access in Vehicular Environments (WAVE) system does not consider time utilization of CCH and SCH. In this paper, we present a novel mechanism to extend MAC protocol, which dynamically adjusts the length of Control Channel (CCH) and Service Channel (SCH) intervals according to vehicle density and load conditions of network. In the proposed...
In this paper, we propose relay transmission protocol based on SoQ(Satisfaction of QoS) for QoS enhancement and analyze the performance of the proposed method in Wireless USB Networks. In the proposed protocol, Wireless USB host executes the Satisfaction of QoS (SoQ) time slot allocation algorithm. And, in order to give devices with scarce resource another chance to improve QoS, the proposed relay...
IRDT (Intermittent Receiver-driven Data Transmission) realizes low-power communication between neighbor sensor nodes. This paper proposes combination IRDT-GEDIR of IRDT and GEDIR which is an on-demand location-based ad-hoc routing protocol. Here, for shorter end-to-end transmission delay, pseudo speed of data message transmission is applied for next-hop selection in an intermediate node and on-line...
This paper introduces a novel Medium Access Control (MAC) strategy for energy efficient wireless data transmissions which reduces energy consumption while minimizing the negative impact on network Quality of Service (QoS). This strategy adaptively adjusts the sleeping window of the mobile devices' wireless transceiver. The proposed mechanism - the Slow sTart Exponential and Linear Algorithm (STELA)...
Military tactical networks require reach back connectivity, and in most cases the only viable solution is a combination of satellite and radio links. This hybrid network is characterized by long delay, transmission errors and relative low capacity. Geostationary satellites add a substantial time delay. Terrestrial wireless packet networks might introduce comparable delays and jitter. Mobility and...
We investigate the impact of the node-selfishness on the network connectivity and the path delay of information dissemination in large scale Ad-hoc networks based on the percolation theory. A network framework with links obeying stationary process is conceived by combining the effects of both node-selfishness and link qualities. The existence of the node cooperation probability boundary is proved...
Wireless devices are responsible for a new era in computing. New networking paradigms such as mobile computing, ad-hoc networks pervasive infrastructures, all offer new possibilities to the user, from experimental technologies lately some of the aforementioned examples tend to become part of ordinary life applications. The medical sector benefits substantially from the use of mobile devices, since...
As a routing algorithm defined in IEEE 802.15.5, server routing (SR) can attain the optimal routes between source and destination nodes. However, we found that it has the following two problems: (1) unicasting the Link State Registrations does not utilize the available topology information, and (2) the relay list of Route Formations includes redundant contents. To address these problems, we propose...
Recent advancements in PHY data rates of communication technologies require efficient MAC mechanisms. IEEE 802.11 MAC compels nodes to defer transmissions to avoid collisions and maintain random and fair channel access. Contention time degrades network performance in terms of bandwidth and delays; this problem exaggerates at higher data rates. In this paper, we propose a frequency-domain backoff scheme,...
This paper introduces the key aspects of a new channel model based upon the Wireless World Initiative New Radio (WINNER)+ channel model for wireless channels in heterogeneous scenarios (e.g. indoor, outdoor and satellite scenarios). It consists of a collection of features created in the extended spatial channel model (SCME) and WINNER projects along with novel modeling approaches. The quasi deterministic...
In the last few years, a large variety of wireless components are increasingly running applications that need real-time and high-bandwidth features. Hence, it is imperative for network service providers to make the best possible to ensure seamless roaming through different wireless technologies. In this context, mobility management remains an important task to be investigated to improve Quality of...
Clustering techniques are effective techniques in reducing energy consumption in wireless sensor networks (WSNs). A data collection process (DCP) is an operation for a base station (BS) to collect a complete set of data from a WSN. Clustering techniques may, however, introduce bottlenecks to a DCP and cause extra delays. For time-sensitive applications, a delay-aware network structure is necessary...
This paper proposes three algorithms based on the contention tree algorithm to improve the system performance by utilizing the different additional of feedback information. These three algorithms are derived from adding of skipped slots and/or adaptive frame size strategies. Average access delay is analyzed to evaluate the system performance which is measured in term of the number of used slots in...
In this paper we propose the channel assignment scheme for multi-channel wireless mesh network (WMN), where each mesh router is equipped with multiple radio interfaces. In real WMN the number of radio interfaces is much higher than the number of non-overlapping channels, which causes a lot of connections between mesh nodes operate on the same radio channel. Increasing number of simultaneous transmissions...
In order to ease congestion phenomenon in the case of limited resources of nodes, this paper presents an adaptive congestion control algorithm based on the node's priority. The proposed algorithm confirms prioritization according to the degree of congestion situation, and then adaptively chooses its probability of accessing channel in order to quickly relieve the congestion in this region. Experimental...
There will be a great of Heterogeneous networks in Next Generation Network. Mobile Satellite system (MSS), great supplement of terrestrial network, provide large scale network coverage and is able to support IP multimedia services. We propose a SIP-based soft handoff scheme for integrated architecture of MSS and UMTS, as well as add satellite access gateway (SAG) in satellite station and terrestrial...
-In recent years, a lot of interest has been drawn to the so-called multiple input multiple output (MIMO) systems in their potential to achieve enormous capacity gains. This increase in capacity is dependent upon the propagation environment exhibiting sufficient scattering. The characterization of MIMO channels is therefore required in order to analyze the performance of such systems in real environments...
This paper investigates traffic related performance for TCP/UDP-based traffic flows in a MANET powered by OLSR with various routing metrics. Besides the ETX (expected transmission count), an alternative is proposed that resorts on a cross-layer approach to obtain PER (packet error rate) estimates from the physical layer. Throughput and latency performance are evaluated for various configurations of...
A cross-layered communication paradigm for integrating search and surveillance applications of Unmanned Aeronautical Ad-Hoc Networks (UAANETs) is proposed. The idea is to accomplish two conflicting applications of UAANETs simultaneously via a single ad-hoc communication architecture. The proposal supports both searching and tracking missions of UAANETs via a unified cross-layer architecture. In order...
The wireless mobile network is a dynamic environment. The characteristics of the wireless mobile communication include limited channel bandwidth, high BER, dynamic change over time, unstable channel quality, mobile node, competition of multiple users to share the channel, and the users' wireless signal interference from other nodes of the shared channel. These characteristics of wireless communication...
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