Design, implementation and performance analysis of dual mode WLAN for network coverage extension

In conventional Wireless Local Area Networks (WLANs) nodes connect only via single hops to the Access Point (AP) thus limiting the reach of the network. There are practical situations where the mobile node may not be able to connect or access the wireless network due to physical limitation, restriction or interruption. Here in this thesis, we address this situation and propose a dual mode wireless local area network wherein we increase network coverage by implementing the ad hoc mode and the infrastructure mode of the 802.11 protocol concurrently. The connection between the remote mobile nodes and the AP is built through peer users, also called bridge nodes, which form an ad-hoc network on the fly to access the already existing WLAN. While designing a network using Dual Mode WLAN referred to as 'DMWLAN', there are many issues that need to be carefully considered. In particular, we emphasize the impact of network parameters such as network throughput of the remote nodes, the reduction of the throughput of the bridge nodes due to excessive traffic flowing through them, and overall network throughput.; Through simulation we demonstrate the merit of DMWLAN and the proposed protocols performance. Our results show that with acceptable degradation of helping nodes performance we can provide network connectivity to nodes outside of the AP's radio range. We report our results from the simulations ran in GloMoSim. (Abstract shortened by UMI.)...