DocumentCode :
1222660
Title :
Optimal Channel-Aware ALOHA Protocol for Random Access in WLANs With Multipacket Reception and Decentralized Channel State Information
Author :
Ngo, Minh Hanh ; Krishnamurthy, Vikram ; Tong, Lang
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of British Columbia, Vancouver, BC
Volume :
56
Issue :
6
fYear :
2008
fDate :
6/1/2008 12:00:00 AM
Firstpage :
2575
Lastpage :
2588
Abstract :
Perfect decentralized channel state information (CSI) is utilized to design an optimal distributed medium access control (MAC) protocol for wireless local area networks (WLANs) with the multipacket reception capability, which is available in CDMA systems for example. In particular, we consider the scenario where a finite number of users transmit packets to a common access point via a channel-aware ALOHA protocol. We analyze the structure of the optimal channel-aware transmission policies for both the spatially homogeneous WLAN system model, where users deploy identical transmission policies, and the spatially heterogeneous WLAN system model, where users are allowed to deploy different transmission policies. It is shown that the optimal transmission policy is nonrandomized and piecewise continuous with respect to the channel state. Furthermore, we prove for CDMA systems, which represent the most important example of networks with the MPR capability, that under a suitable condition, there exists a channel state threshold beyond which it is optimal not to transmit. Last, we propose a provably convergent stochastic approximation algorithm for estimating the optimal transmission policy for spatially homogeneous networked users. Numerical studies illustrate the performance of the algorithm and the degenerate, nonrandomized structure of the optimal transmission policy.
Keywords :
access protocols; stochastic processes; wireless LAN; wireless channels; CDMA systems; decentralized channel state information; medium access control protocol; multipacket reception; optimal channel-aware ALOHA protocol; optimal distributed MAC protocol; optimal transmission policy; provably convergent stochastic approximation algorithm; random access; spatially homogeneous WLAN system model; wireless local area networks; Access protocols; Approximation algorithms; Channel state information; Media Access Protocol; Multiaccess communication; Physical layer; Stochastic processes; Time division multiple access; Wireless LAN; Wireless application protocol; Channel state information; gradient estimation; multipacket reception; optimal transmit policy; stochastic gradient algorithms; wireless local area network;
fLanguage :
English
Journal_Title :
Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1053-587X
Type :
jour
DOI :
10.1109/TSP.2007.911284
Filename :
4524053
Link To Document :
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