Distributed control DAMA protocol for use with a processing communications satellite

A distributed demand assigned multiple access control scheme (22) for use in connection with a processing satellite communications system, where multiple users are assigned to a common TR as part of a sharing set (12). The control scheme (22) of the invention makes use of a reservation procedure by transmitting set addressed reservation messages in a contentious control flow to reserve data transfer time in a non-contentious main flow. Each user of the sharing set is synchronized with each other and with a known synchronization variable defined by the next available uplink time slot available to transmit data in the main flow (10). When a user of a sharing set wishes to send data in the main flow, it transmits the set addressed reservation message in the control flow (26), and if the set addressed reservation message is returned in the satellite downlink (28), the terminal knows that all of the users of the shared set received the message. That reserved time interval in the main flow is now owned by that user, and each user in the shared set updates its next available uplink time slot based on the reserved time. By gaining access to the shared set, each user is limited to a predetermined peak cell rate, is guaranteed a sustained cell rate, and is limited to a maximum reservation length. The maximum reservation length identifies the largest number of data units transmitted per reservation, and defines a worst case delay that the user must wait to gain a reservation. A user may piggyback a reservation by sending a set addressed reservation message during transmission of data in the main flow.