Cooperative Mac Protocols for IEEE 802.11 Ad Hoc Networks

Cooperative Mac Protocols for IEEE 802.11 Ad Hoc Networks
Author: Niraj Agarwal
Publisher:
Total Pages: 434
Release: 2006
Genre: Computer networks
ISBN:
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One of the factors that significantly affects the performance of wireless networks is fading. There are several techniques to overcome the detrimental effects of multipath fading, the most common being to provide diversity, i.e. statistically independent channels from the source to the destination.

Cooperative Multi-channel MAC Protocols for Wireless Ad Hoc Networks

Cooperative Multi-channel MAC Protocols for Wireless Ad Hoc Networks
Author: Yuhan Moon
Publisher:
Total Pages: 151
Release: 2010
Genre: Ad hoc networks (Computer networks)
ISBN:
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Today, many wireless networks are single-channel systems. However, as the interest in wireless services increases, the contention by nodes to occupy the medium is more intense and interference worsens. One direction with the potential to increase system throughput is multi-channel systems. Multi-channel systems have been shown to reduce collisions and increase concurrency thus producing better bandwidth usage. However, the well-known hidden- and exposed-terminal problems inherited from single-channel systems remain, and a new channel selection problem is introduced. In this dissertation, Multi-channel medium access control (MAC) protocols are proposed for mobile ad hoc networks (MANETs) for nodes equipped with a single half-duplex transceiver, using more sophisticated physical layer technologies. These include code division multiple access (CDMA), orthogonal frequency division multiple access (OFDMA), and diversity. CDMA increases channel reuse, while OFDMA enables communication by multiple users in parallel. There is a challenge to using each technology in MANETs, where there is no fixed infrastructure or centralized control. CDMA suffers from the near-far problem, while OFDMA requires channel synchronization to decode the signal. As a result CDMA and OFDMA are not yet widely used. Cooperative (diversity) mechanisms provide vital information to facilitate communication set-up between source-destination node pairs and help overcome limitations of physical layer technologies in MANETs. In this dissertation, the Cooperative CDMA-based Multi-channel MAC (CCM-MAC) protocol uses CDMA to enable concurrent transmissions on each channel. The Power-controlled CDMA-based Multi-channel MAC (PCC-MAC) protocol uses transmission power control at each node and mitigates collisions of control packets on the control channel by using different sizes of the spreading factor to have different processing gains for the control signals. The Cooperative Dual-access Multi-channel MAC (CDM-MAC) protocol combines the use of OFDMA and CDMA and minimizes channel interference by a resolvable balanced incomplete block design (BIBD). In each protocol, cooperating nodes help reduce the incidence of the multi-channel hidden- and exposed-terminal and help address the near-far problem of CDMA by supplying information. Simulation results show that each of the proposed protocols achieve significantly better system performance when compared to IEEE 802.11, other multi-channel protocols, and another protocol CDMA-based.

Enhanced IEEE 802.11.p-Based MAC Protocols for Vehicular Ad Hoc Networks

Enhanced IEEE 802.11.p-Based MAC Protocols for Vehicular Ad Hoc Networks
Author: Yamen Nasrallah
Publisher:
Total Pages:
Release: 2017
Genre:
ISBN:
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The Intelligent Transportation System (ITS) is a cooperative system that relies on reliable and robust communication schemes among vehicles and between vehicles and their surroundings. The main objective of the ITS is to ensure the safety of vehicle drivers and pedestrians. It provides an efficient and reliable transportation system that enhances traffic management, reduces congestion time, enables smooth traffic re-routing, and avoids economic losses. An essential part of the ITS is the Vehicular Ad hoc Network (VANET). VANET enables the setup of Vehicle-to-Vehicle (V2V) as well as Vehicle-to-Infrastructure (V2I) communication platforms: the two key components in the ITS. The de-facto standard used in wireless V2V and V2I communication applications is the Dedicated Short Range Communication (DSRC). The protocol that defines the specifications for the Medium Access Control (MAC) layer and the physical layer in the DSRC is the IEEE 802.11p protocol. The IEEE 802.11p protocol and its Enhanced Distributed Channel Access (EDCA) mechanism are the main focus of this thesis. Our main objective is to develop new IEEE 802.11p-based protocol for V2V and V2I communication systems, to improve the performance of safety-related applications. These applications are of paramount importance in ITS, because their goal is to decrease the rate of vehicle collisions, and hence reduce the enormous costs associated with them. In fact, large percentage of vehicle collisions can be easily avoided with the exchange of relevant information between vehicles and the Road Side Units (RSUs) installed on the sides of the roads. In this thesis, we propose various enhancements to the IEEE 802.11p protocol to improve its performance by lowering the average end-to-end delay and increasing the average network throughput. We introduce multiple adaptive algorithms to promote the QoS support across all the Access Categories (AC) in IEEE 802.11p. We propose two adaptive backoff algorithms and two algorithms that adaptively change the values of the Arbitrary Inter-Frame Space (AIFS). Then we extend our model to be applied in a large-scale vehicular network. In this context, a multi-layer cluster-based architecture is adopted, and two new distributed time synchronization mechanisms are developed.

Multiaccess, Mobility and Teletraffic in Wireless Communications: Volume 4

Multiaccess, Mobility and Teletraffic in Wireless Communications: Volume 4
Author: Ezio Biglieri
Publisher: Springer Science & Business Media
Total Pages: 313
Release: 2013-03-09
Genre: Computers
ISBN: 1475759207
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The unrelenting growth of wireless communications continues to raise new research and development problems that require unprecedented interactions among communication engineers. In particular, specialists in transmission and specialists in networks must often cross each other's boundaries. This is especially true for CDMA, an access technique that is being widely accepted as a system solution for next-generation mobile cellular systems, but it extends to other system aspects as well. Major challenges lie ahead, from the design of physical and radio access to network architecture, resource management, mobility management, and capacity and performance aspects. Several of these aspects are addressed in this volume, the fourth in the edited series on Multiaccess, Mobility and Teletraffic for Wireless Communications. It contains papers selected from MMT'99, the fifth Workshop held on these topics in October 1999 in Venezia, Italy. The focus of this workshop series is on identifying, presenting, and discussing the theoretical and implementation issues critical to the design of wireless communication networks. More specifically, these issues are examined from the viewpoint of the impact each one of them can have on the others. Specific emphasis is given to the evolutionary trends of universal wireless access and software radio. Performance improvements achieved by spectrally efficient codes and smart antennas in experimental GSM testbeds are presented. Several contributions address critical issues regarding multimedia services for Third-Generation Mobile Radio Networks ranging from high rate data transmission with CDMA technology to resource allocation for integrated Voice/WWW traffic.

Cooperative WLAN Protocols for Multimedia Communication

Cooperative WLAN Protocols for Multimedia Communication
Author: Azadeh Ettefagh
Publisher:
Total Pages: 224
Release: 2011
Genre:
ISBN: 9783832527747
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The IEEE 802.11n specifies MIMO techniques to enhance data rate in WLANs. However, it can support only MIMO point-to-point links. On the other hand, it is known that multiuser MIMO techniques can significantly increase the spectral efficiency of networks. In this thesis, to realise MIMO spatial multiplexing gain in networks with single-antenna stations and to enhance network performance, cooperative protocols are considered with respect to both PHY and MAC layers.In order to utilise cooperative signalling in WLANs, the MAC protocol has to be modified. The existing CSMA/CA-based MAC avoids any interference and supports only point-to-point links. To enhance IEEE 802.11n system in a way that multiple users can transmit simultaneously, a novel cluster-based CSMA/CA has been proposed in this work. Our study has shown that the CB-CSMA/CA can significantly improve throughput and reduce delay in different types of infrastructure or ad hoc networks with single-hop or two-hop links. Furthermore, we have shown that throughput of CB-CSMA/CA can further be improved by taking cross-layer parameters into account, when forming the clusters or defining the backoff models.

Mobile Ad Hoc Networking

Mobile Ad Hoc Networking
Author: Stefano Basagni
Publisher: John Wiley & Sons
Total Pages: 479
Release: 2004-10-07
Genre: Technology & Engineering
ISBN: 0471656887
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From physical issues up to applications aspects, Mobile Ad Hoc Networking comprehensively covers all areas of the technology, including protocols and models, with an emphasis on the most current research and development in the rapidly growing area of ad hoc networks. All material has been carefully screened for quality and relevance and reviewed by the most renowned and involved experts in the field. Explores the most recent research and development in the rapidly growing area of ad hoc networks. Includes coverage of ad hoc networking trends, possible architectures, and the advantages/limits for future commercial, social, and educational applications. Ad hoc networks have been an intense area of research and development but many products that fully utilize this technology are only now being widely deployed throughout the world.

NETWORKING 2007. Ad Hoc and Sensor Networks, Wireless Networks, Next Generation Internet

NETWORKING 2007. Ad Hoc and Sensor Networks, Wireless Networks, Next Generation Internet
Author: Ian F. Akyildiz
Publisher: Springer Science & Business Media
Total Pages: 1278
Release: 2007-04-27
Genre: Computers
ISBN: 3540726055
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This book constitutes the refereed proceedings of the 6th International IFIP-TC6 Networking Conference, NETWORKING 2007, held in Atlanta, GA, USA in May 2007. The 99 revised full papers and 30 poster papers were carefully reviewed and selected from 440 submissions. The papers are organized in topical sections on ad hoc and sensor networks: connectivity and coverage, scheduling and resource allocation, mobility and location awareness, routing, and key management; wireless networks: mesh networks, mobility, TCP, MAC performance, as well as scheduling and resource allocation; next generation inte.

A Cognitive PHY-MAC Cooperative Protocol for Low-Power Short-Range Wireless Ad-Hoc Networks Using UWB PPM Radios

A Cognitive PHY-MAC Cooperative Protocol for Low-Power Short-Range Wireless Ad-Hoc Networks Using UWB PPM Radios
Author: Jose M. Almodovar-Faria
Publisher:
Total Pages: 146
Release: 2014
Genre:
ISBN:
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Pulse-position modulation (PPM) is a well-known digital modulation scheme that when used in UWB radios can achieve simple low-cost architectures and more importantly a very low-power operation while offering relatively good data rates and bit-error rate (BER) performance. The DCF function described by the IEEE 802.11 WLAN standard is used quite often as the MAC protocol when implementing wireless networks in general and has proven to be efficient for many applications. This doctoral dissertation presents a new cognitive and cooperative protocol between the physical (PHY) layer and the MAC sublayer for wireless ad-hoc networks using PPM UWB radios. By a cognitive estimation of the wireless channel and the cooperation between the MAC and PHY layers, the cognitive protocol can dynamically adjust the transmission data rate between two nodes optimizing their communication. Simulations show that the protocol improves the overall network performance in terms of message delivery ratio and average transmission delay.