Computer Network Research.

A major area of research during this period has been that of packet switching in radio channels. The problem here is to make a contribution to the design of terminal access networks, namely those which lie between the terminal itself and perhaps a high level network such as the ARPANET. The communication medium studied is that of radio transmission in a digital mode and takes advantage of the resource sharing and packet switching principles which were developed for the study of the ARPANET and for the study of satellite communications in a packet switched mode. The central issues here involve the analysis of the behavior of a collection of terminals communicating with a radio repeater in a highly uncontrolled fashion. The key idea here as opposed to satellite packet switching is that terminals may listen to other terminals transmissions by sensing the radio frequency carrier and if the channel is sensed busy than other terminals will inhibit their own transmissions thereby preventing a collision. The hidden terminal problem is studied as well as a busy tone solution to that problem.