In this project, we aim at designing resource management schemes and adaptive protocols for wireless networks that are capable of directional transmission/reception. In contrast to an isotropic antenna, which transmits the same amount of power is all directions, a directional antenna has preferred direction(s) for transmission and reception; while transmitting, the antenna concentrates the power in certain direction(s), and while receiving the antenna has greater sensitivity for electromagnetic radiation in certain direction(s). Compared with an isotropic antenna, directional antennas have the potential to significantly improve the network throughput and/or reduce the required per-bit energy consumption. For instance, sectoring provided by directional antennas enables a base station to serve more than one cell at a time, thus improving the capacity of a cellular network. Because of these advantages, directional antennas have been adopted in IS-95 and 3G cellular systems. Recently, directional antennas have been suggested for mobile ad hoc networks (MANETs) as well as wireless mesh networks (WiMAX). However, classic MAC and routing protocols in such networks have been designed for omni-directional communications, and extending these protocols to handle directional communications is fraught with challenges. Chief among them is new forms of the hidden-terminal problem (attributed to the asymmetry of the communications), side-lobe interference (due to energy leakage), and transmitter deafness. To address these challenges, we are developing novel, power-controlled MAC and routing protocols for MANETs with directional antennas. Two MAC protocols (called DMAP and LCAP) have been developed and evaluated using simulations and analysis. The latter protocol holds greater promise for practical implementation. Its novelty lies in using an elaborate packet-based power control strategy that is aimed at increasing the channel's spatial reuse by allowing interference-limited, concurrent directional transmissions to take place in the same vicinity. By employing a separate control channel and by accounting for minor-lobe interference, LCAP alleviates many of the channel access problems that afflict commonly used MAC protocols.