Intelligent Local Avoided Collision (iLAC) MAC Protocol for Very High Speed Wireless Network

Dinh Chi HIEU
Verotiana Hanitriniala RABARIJAONA

IEICE TRANSACTIONS on Communications   Vol.E95-B    No.2    pp.392-400
Publication Date: 2012/02/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E95.B.392
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Network
CSMA/CA,  DCF,  Markov chain,  

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Future wireless communication systems aim at very high data rates. As the medium access control (MAC) protocol plays the central role in determining the overall performance of the wireless system, designing a suitable MAC protocol is critical to fully exploit the benefit of high speed transmission that the physical layer (PHY) offers. In the latest 802.11n standard [2], the problem of long overhead has been addressed adequately but the issue of excessive colliding transmissions, especially in congested situation, remains untouched. The procedure of setting the backoff value is the heart of the 802.11 distributed coordination function (DCF) to avoid collision in which each station makes its own decision on how to avoid collision in the next transmission. However, collision avoidance is a problem that can not be solved by a single station. In this paper, we introduce a new MAC protocol called Intelligent Local Avoided Collision (iLAC) that redefines individual rationality in choosing the backoff counter value to avoid a colliding transmission. The distinguishing feature of iLAC is that it fundamentally changes this decision making process from collision avoidance to collaborative collision prevention. As a result, stations can avoid colliding transmissions with much greater precision. Analytical solution confirms the validity of this proposal and simulation results show that the proposed algorithm outperforms the conventional algorithms by a large margin.