Dynamic Channel Assignment Strategy for Uncoordinated OSA- Enabled WLAN Mrs. Sandhya Tanpure Department of Electronics & Tele-Communication Ramrao Adik Institute of Technology Nerul, Navi Mumbai Maharashtra, India Prof. Sujata Kadam Department of Electronics & Tele-Communication Ramrao Adik Institute of Technology Nerul, Navi Mumbai Maharashtra, India Mrs. Mrunalini Gavfale Department of Electronics & Tele-Communication Ramrao Adik Institute of Technology Nerul, Navi Mumbai Maharashtra, India Abstract Efficient channel assignment is crucial for successful deployment and operation of IEEE 802.11-based WLANs. The use of Wireless Local Area Networks (WLANs) based on the IEEE 802.11 standard has increased significantly in the last years, especially for applications in both residential and commercial environments. Due to dense deployments of Wireless Local Area Networks (WLANS) the amount of available spectrum in ISM bands constitute a key limiting factor & causes congestion. A promising approach to alleviate ISM band congestion problems in highly dense WLAN scenarios consists of exploiting opportunistic spectrum access (OSA) to underutilized bands under a primary-secondary model. The developed distributed channel assignment algorithm will be valid for uncoordinated WLAN deployments where access points do not follow any specific planning and they could belong to different administrative domains. Unlike existing channel assignment schemes proposed for legacy WLANs, channel assignment mechanisms for OSA-enabled WLAN should address two distinguishing issues: channel prioritization and spectrum heterogeneity. So, objective of this proposed strategy for channel assignment is to reduce congestion in the crowded ISM band by allowing some access points (APs) to opportunistically operate in a primary band. General Terms Channel Assignment Keywords Channel allocation, IEEE 802.11, wireless Networks, OSA, WLAN, Distributed algorithm 1. Introduction The use of Wireless Local Area Networks (WLANs) based on the IEEE 802.11 standard has increased significantly in the last years, especially for applications in both residential and commercial environments. With the increased popularity and deployment of Wireless Local Area Networks (WLANs), efficient management of wireless spectrum is becoming increasingly important. Dense deployments of Wireless Local Area Networks (WLANs) are rapidly increasing in urban zones, especially for providing Internet access within residential and office buildings by installing uncoordinated individual access points (AP). These deployments are leading to uncontrolled and excessive levels of interference in unlicensed bands that, ultimately, may turn into both an unpredictable degradation in network performance and unfairness among APs. In these scenarios, distributed channel assignment mechanisms constitute the main tool for reducing as much as possible the level of interference between neighboring WLANs in order not to impair individual network performance [1]. Thus far, WLAN distributed channel assignment problem in ISM bands has received a lot of attention in the research community [2], [3]. However, regardless of the ability of the different channel assignment algorithms to improve WLAN performance, the amount of available spectrum in ISM bands for WLAN use can still constitute a key limiting factor in dense deployments. Hence, the exploitation of additional bands for WLANs (e.g., licensed bands used opportunistically) can help improve the performance of such networks. Potential availability of unused portions of the radio spectrum (i.e., white spaces, WS) to be exploited opportunistically is supported by some recent studies [4]. As a result, major efforts are being conducted in both regulatory and standardization bodies to set out the regulatory and technical framework that will enable opportunistic spectrum access to WSs [5]. Hereafter, WLAN equipment able to use WSs in an opportunistic manner will be referred to as OSA-enabled WLAN. An uncoordinated deployment of OSA-enabled WLAN may also benefit from having appropriate channel assignment mechanisms to choose the operational channel in each AP among those available either in unlicensed ISM bands or in a given primary band 3227 International Journal of Engineering Research & Technology (IJERT) Vol. 2 Issue 11, November - 2013 ISSN: 2278-0181 www.ijert.org IJERTV2IS110970