A hybrid contention-based time-division multiaccess (TDMA) protocol is proposed and studied. Channel time is organized into frames, each consisting of reservation, fixed, and variable subframes. Users are divided into groups. Each group is given a data slot in the fixed subframe that is open to users in that group on the basis of contention. Each user can also place his demand in the reservation subframe. The number of slots assigned to a particular user is based on the information gathered from the other two subframes. Performance analyses, both transient and steady-state, are successfully carried out. Computer simulations verify the analyses.>

The performance of a differential PCM type adaptive reservation multiaccess technique is studied in this correspondence. The frame structure of the time-axis remains identical to that in [1]. However, channel reservation is handled differently. Analyses, both transient and steady-state, have been successfully completed. Results obtained include average frame length, queue length, average delay, etc. The validity of analysis is also verified by computer simulations. Through examples we witness that this new protocol generally has better performance than [1].