Recent years have seen significant interest in using the multihop wireless networking paradigm for building mesh networks, ad hoc networks, and sensor networks. A key challenge in multihop wireless networks is to provision for sufficient network capacity to meet user requirements. Several approaches have been proposed to improve the network capacity in multihop networks, ranging from approaches that improve the efficiency of existing protocols, to approaches that use additional resources. In this dissertation, we propose to use additional frequency spectrum, as well as improve the efficiency of using existing frequency spectrum, for improving network capacity. Widely used wireless technologies, such as IEEE 802.11, provision for multiple frequencyseparated channels in the available frequency spectrum. Commercially available wireless network interfaces can typically operate over only one channel at a time. Due to cost and complexity constraints, the total number of interfaces at each node is expected to be fewer than the total number of channels available in the network. Under this scenario with fewer interfaces per node than channels, several challenges have to be addressed before all the channels can be utilized. In this dissertation, we have established the asymptotic capacity of multichannel wireless networks with varying number of channels and interfaces. Capacity analysis has shown that it is feasible

Abstract — This paper presents an optimization of PSM to improve its energy conservation. According to PSM, time is divided into beacon intervals. At the beginning of each beacon interval, all stations must be awake during a specific period called ATIM window to be able to send and receive synchronization messages and announcements of buffered data frames. PSM specifies that a station having sent or received an announcement or having sent a beacon must remain awake during the entire beacon interval. This may lead to wasting energy specially at light traffic loads where stations should conserve the most. We propose an enhancement called the Traffic Aware Power Saving Mode (TA-PSM) to solve this problem by allowing nodes to enter the doze state when they are no more involved in data delivery even if they have already sent a beacon, an ATIM or an ATIM-ACK. Our objective is to reduce the energy consumption without any throttling to throughput. Extensive simulations based on fixed and dynamic topologies showed that TA-PSM provides a much better energy conservation and a lower power consumption per delivered data frame.