Onboard control of demand assigned multiple access protocol for satellite ATM networks

A demand assigned multiple access system for coordinating the transmission of data from a processing satellite uplink and downlink in a satellite communications network, said system comprising:

• a user Earth terminal, said user Earth terminal including a media access control layer including a plurality of media access control channels for transmitting data on the uplink, wherein one of the control channels is a contentious shared reservation channel and one of the control channels is a non-contentious shared data channel, said terminal transmitting a reservation request to the satellite on the contentious control channel to bid for an available time slot to transmit the data on the non-contentious shared data channel;
• at least one switch positioned receiving the uplink transmissions form the terminal on the satellite uplink, said switch identifying the reservation request and routing the request in the satellite;
• a media access controller responsive to the reservation request from the switch, said media access controller determining whether to grant, deny or delay the reservation request based on a plurality of predetermined criteria, said media access controller generating a reservation reply message to be sent on the satellite downlink;
• a real-time bandwidth estimator module that determines the available capacity in the satellite downlink and sends a signal indicative of the available capacity to the media access controller;
• a flow-control module on the satellite that senses congestion in a destination port and sends a signal indicative of the congestion to the media access controller;
• and
• an available bit rate processor that identifies the available bit rate in a standard ATM service available on the satellite uplink and downlink destinations, and sends a signal indicative of available bit rate to the media access controller.

A method for transmitting data on a processing satellite uplink in a satellite communications network, comprising the steps of:

• sending a reservation request by a requesting user on a control flow channel of the satellite uplink to bid for an available slot to transmit data on a main flow channel;
• processing the reservation request in the satellite to determine whether to grant, deny or delay the reservation request based on the service and price class of the requesting user, the amount of data already transmitted by the requesting user, the number of other users using the main flow channel, the congestion state of a destination downlink port for the data, the available bandwidth capacity of the satellite downlink, and the flow rate of data through the satellite network;
• transmitting a reservation message on a satellite downlink to the requesting user of the satellite's decision to grant, deny or delay the reservation request, wherein if the reservation message is a reservation grant message, the reservation grant message includes information of the time, frequency and duration for transmitting the data on the main flow channel;
• and
• transmitting the data on the main flow channel when the time for transmitting the data arrives.