Efficient multicasting over large-scale WLANs through controlled association

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.comnet.2008.09.013 Byline: Ai Chen, Dongwook Lee, Prasun Sinha Keywords: Wireless LAN; Association control; Algorithm/protocol design; Algorithm/protocol analysis Abstract: Support for efficient multicasting in WLANs can enable new services such as streaming of TV channels, radio channels, and visitor's information. With increasing deployments of large-scale WLANs, such services can be made available to a large number of users. However, any new multicast based services must minimally impact the existing unicast services which are currently the core services offered by most WLANs. In this paper, we leverage the flexibility of associating with different access-points (APs), which occurs often due to overlapping coverage of APs, to optimize the network's objective. Motivated by different revenue functions and network scenarios, three different optimization objectives are considered which are: maximizing the number of admitted users (MNU), balancing the load among APs (BLA), and minimizing the load of APs (MLA). We show that these problems are NP-hard and present centralized approximation algorithms and distributed approaches to solve them. These algorithms compute which AP a user should be associated with. Using simulations we evaluate their performance and compare them to a naive approach in which users associate to the AP with the best RSSI (Received Signal Strength Indicator). Author Affiliation: Department of Computer Science and Engineering, The Ohio State University, 395 Dreese Laboratories, 2015 Neil Avenue, Columbus, OH 43210-1277, USA Article History: Received 15 January 2008; Revised 15 September 2008; Accepted 16 September 2008 Article Note: (miscellaneous) Responsible Editor A. Capone