Method and apparatus for isochronous datagram delivery over contention-based data link

A method for isochronous datagram delivery in a contention-based communication system having a receiving station and a plurality of sending stations, comprising:

• scheduling a transmission time for each of the plurality of sending stations wherein each of the plurality of sending stations is in contention with others of the sending stations for transmission times;
• communicating a scheduled transmission time to a first of the plurality of sending stations, the scheduled transmission time being reserved for transmission of data by the first of the plurality of sending stations;
• receiving a request from a second of the plurality of sending stations to transmit a substantially isochronous datagram, the request from the second of the plurality of sending stations having a higher priority than the first of the plurality of sending stations;
• interrupting the scheduled transmission time reserved for transmission of data by the first of the plurality of sending stations;
• during the interruption, receiving the substantially isochronous datagram transmitted from the second of the plurality of sending stations to the base station;
• and
• resuming receiving the data transmitted by the interrupted first of the plurality of sending stations.

A method for scheduling polling in a contention-based communication system having a sending station and a receiving station, comprising:

• requesting a transmission time for the sending station to transmit a datagram to the receiving station;
• monitoring a number of datagrams awaiting transmission from the sending station to the receiving station;
• determining a polling rate value based on the number of datagrams awaiting transmission;
• sending data related to the polling rate value to the receiving station;
• transmitting a datagram to the receiving station at a polling rate based on the polling rate value received from the sending station;
• adjusting the polling rate value to increase the polling rate if the number of datagrams awaiting transmission increases above a first predetermined threshold;
• and
• adjusting the polling rate value to decrease the polling rate if the number of datagrams awaiting transmission decreases below a second predetermined threshold.

A system for isochronous datagram delivery in a contention-based communication system having a plurality of sending stations, each having a communications control device, comprising:

• a receiving station having a communications control device capable of communicating with the plurality of sending stations;
• and
• a receiving station scheduler configured to schedule a transmission time for a first of the plurality of sending stations;
• wherein the receiving station communications control device is configured to receive a request from a second of the plurality of sending stations to transmit a substantially isochronous datagram, wherein the receiving station scheduler is further configured to interrupt the scheduled transmission time reserved for transmission of data by the first of the plurality of sending stations, and during the interruption, the receiving station communications control device is configured to receive the substantially isochronous datagram from the second of the plurality of sending stations to the receiving station.

A system for isochronous datagram delivery in a contention-based communication system with a receiving station having a communications control device, comprising:

• plurality of sending stations, each having a communications control device capable of communicating with the receiving station;
• a first of the plurality of sending stations having a scheduled transmission time for transmitting data to the receiving station;
• and
• a second of the plurality of sending stations configured to transmit a request to send a substantially isochronous datagram to the receiving station;
• wherein the second of the plurality of sending stations is configured to respond to a poll from the receiving station received by the second sending station communications control device by transmitting a substantially isochronous datagram to the receiving station during the transmission time scheduled for the first of the plurality of sending stations.