Adjustable transmission power for mobile communications with omnidirectional and directional antennas in a one- and multi-hop environment

A model for analyzing the performance of a multihop S-ALOHA packet radio network is presented. Analytic results from this model show that adjustable transmission power improves the network performance substantially. A vehicle, before transmitting to another one, adjusts its transmission power such that the other vehicle is just reached. This minimizes the area covered by a transmission and reduces the possible distance to potential receivers of other ongoing transmissions, resulting in a higher throughput and a reduced backlog time. It is shown that adjusting the transmission power is very promising in terms of network performance in a hidden-station environment and therefore shows promise for RTI (road traffic informatics) communication networks, especially if the probability of selecting a receiving vehicle is a function of distance