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Eliminating Explicit contention from Channel Access in Distributed Wireless Networks

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China Communications 2019年第5期16卷 70-82页

作者： Aijing Li Chao Dong Fan Wu Shaojie Tang Guihai Chen Qihui Wu Department of Computer Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China College of Communications Engineering PLA Army Engineering UniversityNanjing 210007China College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China Department of Information Systems University of Texas at DallasTexas 75080USA

Emerging techniques such as WiFi direct makes the objective of always-on be true. People can easily chat and share files with nearby friends even without AP(Access Point) or cellular coverage. In this paper, we focus on the channel efficiency issue of APfree Wi-Fi networks, which can be easily constructed in the subway, in a high-speed railway, or when camping in the wild. Today IEEE 802.11 DCF is the most commonly used MAC protocol for Wi-Fi networks, however, due to the control messages and backoff time, channel efficiency in high data rate networks can be extremely low. To solve this, we propose CD-MAC, which allows control messages to be transmitted with data packets concurrently, and thus eliminates the overheads of backoff and explicit contention. To maintain the reception reliability, we redesign the control messages and use signal detection in PHY instead of bits decoding to detect them. In MAC layer, CD-MAC is built upon our Correlation Detection based PHY. We have implemented and evaluated CD-MAC using USRP N210. Evaluation results show that CD-MAC can achieve over 95.5% channel efficiency and provide throughput gains of up to 80%, 60%, and 29.1% compared with DCF, 802.11 ec, and back2F, respectively.

关键词： implicit contention correlation detection media access ad hoc networks OFDM USRP

A Novel Packet Switch Node Architecture for contention Resolution in Synchronous Optical Packet Switched Networks

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International Journal of Communications, Network and System Sciences 2009年第6期2卷 562-568页

作者： Virendra Singh SHEKHAWAT Dinesh Kumar TYAGI V. K. CHAUBEY Birla Institute of Technology & Science

Packet contention is a key issue in optical packet switch (OPS) networks and finds a viable solution by including optical buffering techniques incorporating fiber delay lines (FDLs) in the switch architecture. The present paper proposes a novel switch architecture for packet contention resolution in synchronous OPS network employing the packet circulation in FDLs in a synchronized manner. A mathematical model for the proposed switch architecture is developed employing packet queuing control to estimate the blocking probability for the incoming traffic. The switch performance is analyzed with a suitable contention resolution al-gorithm through the computer simulation. The simulation results substantiate the proposed model for the switch architecture.

关键词： Fiber Delay Lines Packet Circulation Optical Packet Switch Networks Packet Delay Probability contention Resolution

MAC Throughput Improvement Using Adaptive contention Window

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Journal of Computer and Communications 2015年第1期3卷 1-14页

作者： Chun-Liang Lin Wei-Ting Chang Min-Huei Lu Department of Electrical Engineering National Chung Hsing University Taichung Taiwan

HomePlug AV (HPAV) is a standard developed by HomePlug Powerline Alliance (HPA) for power line communication. In HomePlug AV, it uses a technology named Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) to reduce collision happened in network. However, when network nodes increase, the contention window number may not be wide enough. It will cause collision probability to increase. In this paper, we introduce a new idea of adaptive contention window which will produce suitable contention window under actual network environment. Our method only requires the information of CSMA/CA parameters. It means that one doesn’t need to correct the original CSMA/CA procedure but substitutes old parameters by the new ones. Simulation experiments conducted in the network simulator NS3 show that compared with HomePlug AV, our method promotes throughput significantly when the node number increases.

关键词： CSMA/CA contention Window Power Line Communication

Performance of Random contention PRMA: A Protocol for Fixed Wireless Access

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International Journal of Communications, Network and System Sciences 2011年第7期4卷 417-423页

作者： Salman Ali AlQahtani Ahed Alshanyour Ashraf Mahmoud Department of Information and Communications Technology King Fahad Security College Computer Engineering Department King Fahd University of Petroleum and Minerals

This paper introduces a packet reservation multiple access (PRMA) with random contention for fixed wireless access communications. The performance of PRMA scheme with random contention is compared with the performances of traditional PRMA under permission contention scheme. The proposed scheme is a simpler contention mechanism that does not depend on a pre-determined permission probability as PRMA under permission contention scheme. In this new method, terminals select the contention slot uniformly from the pool of remaining free slots in the current frame. We evaluate the performance of the new contention mechanism in terms of various metrics including maximum number of carried voice calls and packet delays for a given acceptable drop rate of voice packets. We show that the new mechanism is superior to that of PRMA under permission contention scheme for loaded systems and is expected to be insensitive for traffic source burstiness.

关键词： contention Scheme Fixed wireless Performance Evaluation PRMA

A Distributed Mechanism for Handling of Adaptive/Intelligent Selfish Misbehaviour at MAC Layer in Mobile Ad Hoc Networks

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Journal of Computer Science & Technology 2009年第3期24卷 472-481页

作者： Raja Gunasekaran Vaidheyanathan Rhymend Uthariaraj Uamapathy Yamini Rajagopalan Sudharsan Selvaraj Sujitha Priyadarshini Department of Information Technology Anna University Ramanujan Computing Centre Anna University

Medium access control （MAC） protocols such as IEEE 802.11 are used in wireless networks for sharing of the wireless medium. The random nature of the protocol operation together with the inherent difficulty of monitoring in the open poses significant challenges. All nodes are expected to comply with the protocol rules. But, some nodes in order to gain greater benefits misbehave by not complying with the rules. One such selfish misbehavior is waiting for smaller back-off intervals when compared to the other nodes in the same subnet. Such selfish misbehavior is being tackled in this paper. A diagnosis scheme and a penalty scheme are being proposed for overcoming such selfish-misbehavior at MAC layer of mobile ad hoc networks which could be extended to other types of networks also.

关键词： WLANs MAC layer DCF contention backoff

Minimization of Collision in Energy Constrained Wireless Sensor Network

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Wireless Sensor Network 2009年第4期1卷 350-357页

作者： Moses Nesa SUDHA Muniappan Lakshapalam VALARMATHI George RAJSEKAR Michael Kurien MATHEW Nagarajan DINESHRAJ Sivasankaran RAJBARATH 不详

Wireless Sensor Networks (WSNs) are one of the fastest growing and emerging technologies in the field of Wireless Networking today. The applications of WSNs are extensively spread over areas like Military, En-vironment, Health Care, Communication and many more. These networks are powered by batteries and hence energy optimization is a major concern. One of the factors that reduce the energy efficiency of the WSN is collision which occurs due to the high density of data packets in a typical communication channel. This paper aims at minimizing the effects of congestion leading to collision in the network by proposing an effective algorithm. This can be done by optimizing the size of the contention window by introducing pa-rameters like source count and α. If the contention window of a node is low, it results in collision. If the size of the contention window of a node is high then it results in a medium access delay. Thus minimizing colli-sion and medium access delay of data packets conserve energy.

关键词： Energy Collision contention Window Wireless Sensor Networks

Performance Analysis of Unified Failure Model for Emerging WiMAX Networks

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Wireless Engineering and Technology 2012年第2期3卷 72-76页

作者： Rajesh Anbazhagan Nakkeeran Rangaswamy Department of Electronics Engineering School of Engineering and Technology Pondicherry University Puducherry India

In this paper, we present a failure model for WiMAX network developed by considering the collision due to contention, unavailability of bandwidth and channel error assuming them as independent events. Using this model, the performance of bandwidth request based on contention resolution with exponential increase and exponential decrease (EIED) backoff is investigated and observed low contention efficiency with high access delay. Hence, we modify the EIED mechanism by computing the backoff factor with average contention window and estimating the response time from the transmission failure. Simulations validate the developed model with modified EIED backoff and shows better performance than conventional scheme.

关键词： WiMAX Medium Access Control contention Resolution Backoff Mechanism

A MAC Scheme with QoS Guarantee for MANETs

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International Journal of Communications, Network and System Sciences 2009年第8期2卷 759-763页

作者： Yanbin YANG Yulin WEI 不详

IEEE 802.11 distributed coordination function (DCF) can alleviate the collision and hidden station problem, but it doesn’t differentiate traffic categories (TC). Therefore, it can’t provide sufficient QoS support for different traffic categories. Recently, a new contention-based enhanced distributed channel access (EDCA) scheme was proposed which provides a probabilistic QoS support. In this paper, an adaptive EDCA scheme with QoS guarantee for mobile ad hoc networks (MANETs) is proposed. In this scheme, the EDCA scheme and the token bucket algorithm (TBA) are combined to adjust the contention window (CW). Our scheme provides the traffic differentiation.

关键词： Mobile Ad Hoc Network Medium Access Control Distributed Coordination Function En-hanced Distributed Channel Access contention Window

The Tunable Parameter Based Deflection Routing Algorithm for OBS Networks

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The Tunable Parameter Based Deflection Routing Algorithm for...