Ad hoc networks are becoming an interesting research area, as they inher-ently support unique network applications for the wireless communications in a rug-ged environment, which requires rapid deployment and is difficult to be provided by an infrastructure network. Many issues need to be addressed for the ad hoc networks. In this dissertation, we propose an efficient distributed coordination function, a dynamic rate adaptation and fragmentation scheme, and a simultaneous frame transmission scheme on the media access control protocol to enhance the power conservation of mobile hosts and to im-prove the network throughput of an ad hoc network. Extensive simulations are studied to evaluate the improvement of the proposed schemes. The results of the simulations exhibit significant improvement to the stan-dard access control protocol. Not only the improvement of the throughput of the ad hoc networks, but also the conservation of the battery power of the mobile hosts were achieved with our schemes.