| Transmitter power control in wireless networks can mitigate interference, increase network capacity, support quality of service through adaptation to network variations, and prolong battery life of mobile terminals. However, since random access algorithms on which MAC protocols of wireless packet networks are based let nodes compete for the channel access with their received power, it has been hard to couple these benefits of power control with the scalability given by packet-based networks. This thesis presents a power controlled MAC layer protocol for next generation mobile computing of which the wireless networks will be packet-based to support data and multimedia traffic.; This protocol leverages a power control algorithm called DPC/ALP. In this thesis, DPC/ALP is thoroughly studied and also extended further for wireless networks employing groupwise serial multiuser detection, and the capacity enhancement of networks employing this algorithm is analyzed. Then, using the properties of DPC/ALP which maintains the desired signal to interference ratio (SIR) at required levels and allows nodes to predict their SIR evolution by probing the channel, the proposed protocol's access control scheme is developed. The protocol can determine not only the network accessibility but also the maximum allowable data rate in multirate wireless networks simultaneously in a short period of time. Service fairness is supported by a simple flow control algorithm which leverages pipelining.; Then, the performance of the designed protocol is evaluated. It is compared to random channel selection in cellular networks and non-persistent CSMA in single-hop networks. The relationship between the routing algorithms (shortest path routing and minimum power routing) and the MAC protocols (the CSMA and the proposed protocol) in multi-hop wireless networks is also studied. Through simulation experiments, the proposed protocol is shown to achieve significant performance gains. |
