BE-DCF: Barring-Enhanced Distributed Coordination Function for Machine Type Communications in IEEE 802.11 networks

One of the limitations of the IEEE 802.11 distributed coordination function (DCF) protocol is its low bandwidth utilization under medium-to-high traffic loads resulting in low throughput and high packet delay. To overcome performance problems, traditional IEEE 802.11 DCF (“DCF”) protocol is modified to the buffer unit multiple access (BUMA) protocol. The BUMA protocol achieves a better system performance by introducing a temporary buffer unit at the medium access control (MAC) layer to accumulate multiple packets and combine them into a single packet (with a header and a trailer) before transmission. This paper provides an in-depth performance evaluation (by simulation) of BUMA for multiuser ad hoc and infrastructure networks. Results obtained show that the BUMA is more efficient than that of DCF. The BUMA protocol is simple and its algorithm (software) can be upgraded to 802.11 networks requiring no hardware changes. The BUMA protocol is described and simulation results are presented to verify the performance.

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StegoFrameOrder—MAC Layer Covert Network Channel for Wireless IEEE 802.11 Networks

Sensors ◽

10.3390/s21186268 ◽

2021 ◽

Vol 21 (18) ◽

pp. 6268

Author(s):

Krzysztof Sawicki ◽

Grzegorz Bieszczad ◽

Zbigniew Piotrowski

Keyword(s):

Ieee 802.11 ◽

Radio Channel ◽

Covert Channel ◽

Distributed Coordination ◽

Medium Access ◽

Deterministic Algorithms ◽

802.11 Networks ◽

Ieee 802.11 Networks ◽

Network Channel ◽

Coordination Function

The proposed StegoFrameOrder (SFO) method enables the transmission of covert data in wireless computer networks exploiting non-deterministic algorithms of medium access (such as the distributed coordination function), especially in IEEE 802.11 networks. Such a covert channel enables the possibility of leaking crucial information outside secured network in a manner that is difficult to detect. The SFO method embeds hidden bits of information in the relative order of frames transmitted by wireless terminals operating on the same radio channel. The paper presents an idea of this covert channel, its implementation, and possible variants. The paper also discusses implementing the SFO method in a real environment and the experiments performed in the real-world scenario.

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Distributed Approach for QoS Guarantee to Wireless Multimedia

Encyclopedia of Mobile Computing and Commerce ◽

10.4018/978-1-59904-002-8.ch034 ◽

2007 ◽

pp. 195-201

Author(s):

K. Chetan ◽

P. Venkataram ◽

R. Sircar

Keyword(s):

Ieee 802.11 ◽

Wireless Multimedia ◽

Distributed Coordination ◽

Access Method ◽

Qos Guarantee ◽

Distributed Approach ◽

Research Areas ◽

Distributed Coordination Function ◽

Active Research ◽

Coordination Function

Providing support for QoS at the MAC layer in the IEEE 802.11 is one of the very active research areas. There are various methods that are being worked out to achieve QoS at MAC level. In this article we describe a proposed enhancement to the DCF (distributed coordination function) access method to provide QoS guarantee for wireless multimedia applications.

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