Network allocation vector

About: Network allocation vector is a research topic. Over the lifetime, 2198 publications have been published within this topic receiving 52734 citations.

Performance analysis of the IEEE 802.11 distributed coordination function

Abstract: The IEEE has standardized the 802.11 protocol for wireless local area networks. The primary medium access control (MAC) technique of 802.11 is called the distributed coordination function (DCF). The DCF is a carrier sense multiple access with collision avoidance (CSMA/CA) scheme with binary slotted exponential backoff. This paper provides a simple, but nevertheless extremely accurate, analytical model to compute the 802.11 DCF throughput, in the assumption of finite number of terminals and ideal channel conditions. The proposed analysis applies to both the packet transmission schemes employed by DCF, namely, the basic access and the RTS/CTS access mechanisms. In addition, it also applies to a combination of the two schemes, in which packets longer than a given threshold are transmitted according to the RTS/CTS mechanism. By means of the proposed model, we provide an extensive throughput performance evaluation of both access mechanisms of the 802.11 protocol.

IEEE 802.11 Wireless Local Area Networks

Abstract: The draft IEEE 802.11 wireless local area network (WLAN) specification is approaching completion. In this article, the IEEE 802.11 protocol is explained, with particular emphasis on the medium access control sublayer. Performance results are provided for packetized data and a combination of packetized data and voice over the WLAN. Our performance investigation reveals that an IEEE 802.11 network may be able to carry traffic with time-bounded requirements using the point coordination function. However, our findings suggest that packetized voice traffic must be handled in conjunction with an echo canceler.

Performance of reliable transport protocol over IEEE 802.11 wireless LAN: analysis and enhancement

Abstract: IEEE 802.11 medium access control (MAC) is proposed to support asynchronous and time bounded delivery of radio data packets in infrastructure and ad hoc networks. The basis of the IEEE 802.11 WLAN MAC protocol is a distributed coordination function (DCF), which is a carrier sense multiple access with collision avoidance (CSMA/CA) with a binary slotted exponential back-off scheme. Since IEEE 802.11 MAC has its own characteristics that are different from other wireless MAC protocols, the performance of reliable transport protocol over 802.11 needs further study. This paper proposes a scheme named DCF+, which is compatible with DCF, to enhance the performance of reliable transport protocol over WLAN. To analyze the performance of DCF and DCF+, this paper also introduces an analytical model to compute the saturated throughput of WLAN. Compared with other models, this model is shown to be able to predict the behavior of 802.11 more accurately. Moreover, DCF+ is able to improve the performance of TCP over WLAN, which is verified by modeling and elaborate simulation results.

Ofdm Wireless LANs: A Theoretical and Practical Guide

Abstract: (NOTE: Each chapter concludes with a Bibliography.) Preface. 1. Background and WLAN Overview. Review of Stochastic Processes and Random Variables. Review of Discrete-Time Signal Processing. Components of a Digital Communication System. OFDM WLAN Overview. Single Carrier Versus OFDM Comparison. 2. Synchronization. Timing Estimation. Frequency Synchronization. Channel Estimation. Clear Channel Assessment. Signal Quality. 3. Modulation and Coding. Modulation. Interleaving. Channel Codes. 4. Antenna Diversity. Background. Receive Diversity. Transmit Diversity. 5. RF Distortion Analysis for OFDM WLAN. Components of the Radio Frequency Subsystem. Predistortion Techniques for Nonlinear Distortion Mitigation. Adaptive Predistortion Techniques. Coding Techniques for Amplifier Nonlinear Distortion Mitigation. Phase Noise. IQ Imbalance. 6. Medium Access Control (MAC)for IEEE 802.ll Networks. MAC Overview. MAC System Architecture. MAC Frame Formats. MAC Data Services. MAC Management Services. MAC Management Information Base. 7. Medium Access Control (MAC) for HiperLAN/2 Networks. Network Architecture. DLC Functions. MAC Overview. Basic MAC Message Formats. PDU Trains. MAC Frame Structure. Building a MAC Frame. MAC Frame Processing. 8. Rapid Prototyping for WLANs. Introduction to Rapid Prototype Design. Good Digital Design Practices. Rapid Prototyping of a WLAN System. Index.

IEEE 802.22: An Introduction to the First Wireless Standard based on Cognitive Radios

Abstract: In November/2004, we witnessed the formation of the first worldwide effort to define a novel wireless air interface (i.e., MAC and PHY) standard based on Cognitive Radios (CRs): the IEEE 802.22 Working Group (WG). The IEEE 802.22 WG is chartered with the development of a CR-based Wireless Regional Area Network (WRAN) Physical (PHY) and Medium Access Control (MAC) layers for use by license-exempt devices in the spectrum that is currently allocated to the Television (TV) service. Since 802.22 is required to reuse the fallow TV spectrum without causing any harmful interference to incumbents (i.e., the TV receivers), cognitive radio techniques are of primary importance in order to sense and measure the spectrum and detect the presence/absence of incumbent signals. On top of that, other advanced techniques that facilitate coexistence such as dynamic spectrum management and radio environment characterization could be designed. In this paper, we provide a detailed overview of the 802.22 draft specification, its architecture, requirements, applications, and coexistence considerations. These not only form the basis for the definition of this groundbreaking wireless air interface standard, but will also serve as foundation for future research in the promising area of CRs.