초록 ▼

A media control approach that supports transmission of data streams with QoS requirements, such as minimum throughput or maximum delay, while adapting to the changing characteristics of the transmission medium. The media control approach includes use of a polling manager and a resource manager. The

A media control approach that supports transmission of data streams with QoS requirements, such as minimum throughput or maximum delay, while adapting to the changing characteristics of the transmission medium. The media control approach includes use of a polling manager and a resource manager. The resource manager provides an admission control procedure that prevents admission of sessions that cannot be supported by the system and allocates network resources needed to support admitted sessions. The polling manager uses an efficient "just in time" polling of stations based on their allocated bandwidth or communication rates. Stations that do not use their allocated rates are polled less often than those which use their allocation, thereby increasing the total throughput of the system and providing proper quality of service support for real-time applications.

대표청구항 ▼

What is claimed is: 1. A method for media access control in a communication system which includes a plurality of communication stations which communicate over a shared communication medium comprising: assigning communication resources in accordance with quality of service requirements of a pluralit

What is claimed is: 1. A method for media access control in a communication system which includes a plurality of communication stations which communicate over a shared communication medium comprising: assigning communication resources in accordance with quality of service requirements of a plurality of communication sessions, including determining a polling pattern; polling each of the communication stations to transmit data over the shared communication medium for the plurality of communication sessions according to a polling pattern; monitoring data transmitted by the communication stations in response to the polling; adapting assignment of the communication resources in accordance with the monitoring, including adapting the polling pattern including for each of the communication sessions adapting a rate of polling associated with said session according to said monitoring and said quality of service requirements by reducing a rate of polling for a session in response to the monitored transmissions for that session corresponding to a reduction in actual rate of transmission for that session; and increasing a rate of polling for a session in response to the monitored transmissions for that session corresponding to an increase in actual rate of transmission for that session; and continuing polling of each of the communication stations according to the adapted polling pattern. 2. The method of claim 1 further comprising: accepting a request to establish a new communication session; admitting the new session if a quality of service requirement for said new session can be provided without exceeding a limit on available communication capacity on the shared communication medium; and rejecting the new session if the quality of service requirement cannot be provided without exceeding the limit on available communication resources. 3. The method of claim 1 wherein assigning communication resources in accordance with the quality of service requirements includes assigning said communication resources according to data rate requirements for the plurality of communication sessions. 4. The method of claim 3 wherein assigning communication resources includes: determining a subset of the plurality of communication sessions that can be provided with data rate requirements for said session; and assigning data rates to each of the subset of sessions in accordance with said data rate requirements. 5. The method of claim 4 wherein monitoring data transmission includes collecting data retransmission statistics, and assigning communication resources includes adjusting data rate requirements in accordance with the collected retransmission statistics. 6. Then method of claim 3 wherein assigning communication resources includes optimizing a utility function subject to a set of constraints. 7. The method of claim 1 wherein assigning communication resources in accordance with the quality of service requirements includes assigning said communication resources according to maximum intervals between polling of the plurality of sessions. 8. The method of claim 1 wherein the polling pattern includes a periodic cycle such that during each period of the cycle a subset of the communication sessions are polled in accordance with their allocated communication resources. 9. The method of claim 1 wherein polling the communication stations to transmit data for the plurality of communication sessions includes: assembling a data message identifying at least one of the communication sessions; and transmitting the data message to one of the communication stations using a wireless transmitter; and wherein monitoring data transmitted by the communication stations includes receiving the data transmissions using a wireless receiver. 10. The method of claim 9 wherein assigning the communication resources is performed at a designated arbiter station, and wherein transmitting the data message includes transmitting the data message from the arbiter station to one or more of the communication stations. 11. The method of claim 10 wherein assigning the communication resources is in addition performed at one or more of the communication stations, and wherein the method further comprises designating one of said one or more communication stations to assume the role of the arbiter station. 12. The method of claim 1 further comprising receiving statistics related to the communication session and adapting assignment of the communication resources further includes allocating the resources in accordance with the received statistics. 13. The method of claim 12 wherein the statistics related to the session includes a queue length for a session, and wherein adapting assignment of the communication resources includes adapting the polling sequence according to the queue length. 14. The method of claim 1 wherein assigning communication resources in accordance with the quality of service requirements includes assigning said communication resources according to maximum delay requirements of the plurality of communication sessions. 15. The method of claim 1 wherein assigning communication resources in accordance with the quality of service requirements includes assigning said communication resources according to security requirements of the plurality of communication sessions. 16. The method of claim 1 wherein polling the communication stations to transmit data includes: assembling a data message identifying a two or more communication sessions originating at two or more of the communication stations and identifying time intervals during which said communication stations are permitted to transmit data over the shared communication medium; and transmitting the data message to said two or more communication stations. 17. The method of claim 1 wherein assigning communication resources includes assigning communication resources for each of a plurality of communication channels one the shared communication medium. 18. The method of claim 17 wherein assigning communication resources for each of the plurality of communication channels includes determining a separate polling pattern for each of said channels. 19. The method of claim 1 wherein the communication system includes a distributed telecommunication system. 20. The method of claim 19 wherein the distributed telecommunication system is a wireless local loop system. 21. An apparatus for controlling media access by a plurality of stations configured to communicate over a shared communication medium in a communication system comprising: means for assigning communication resources in accordance with quality of service requirements of a plurality of communication sessions, including a means for determining a polling pattern; means for polling each of the communication stations to transmit data over the shared communication medium for the plurality of communication sessions according to the polling pattern; means for monitoring data transmitted by the communication stations in response to the polling; and means for adapting assignment of the communication resources in accordance with the monitoring, including adapting the polling pattern including for each of the communication sessions adapting a rate of polling associated with said session according to said monitoring and said quality of service requirements by reducing a rate of polling for a session in response to the monitored transmissions for that session corresponding to a reduction in actual rate of transmission for that session; and increasing a rate of polling for a session in response to the monitored transmissions for that session corresponding to an increase in actual rate of transmission for that session. 22. The apparatus of claim 21 further comprising: means for accepting a request to establish a new communication session over the shared communication medium; means for admitting the new communication session if a quality of service requirement for said session can be provided without exceeding a limit on available communication resources; and means for rejecting the new session if the quality of service requirement cannot be provided without exceeding the limit on available communication resources. 23. A computer readable medium encoded with software for causing a computer to perform the functions of: assigning communication resources in accordance with quality of service requirements of a plurality of communication sessions on a shared communication medium, including determining a polling pattern; polling each of plurality of communication stations to transmit data for the plurality og communication sessions according to a polling pattern; monitoring data transmitted over the shared communication medium by the communication stations in response to the polling; adapting assignment of the communication resources in accordance with the monitoring, including adapting the polling pattern including for each of the communication sessions adapting a rate of polling associated with said session according to said monitoring and said quality of service requirements by reducing a rate of polling for a session in response to the monitored transmissions for that session corresponding to a reduction in actual rate of transmission for that session; and increasing a rate of polling for a session in response to the monitored transmissions for that session corresponding to an increase in actual rate of transmission for that session; and continuing polling of each of the communication stations according to the adapted polling pattern. 24. The computer readable medium of claim 23, wherein the software further causing the computer to perform the functions of: accepting a request to establish a new communication session; admitting the new communication session if a quality of service requirement for said session can be provided without exceeding a limit on available communication resources; and rejecting the new session if the quality of service requirement cannot be provided without exceeding the limit on available communication resources. 25. The computer readable medium of claim 24 wherein the quality of service requirement for the new communication session includes a minimum required and a maximum desired data rate. 26. An apparatus for polling a plurality of stations configured to communicate over a shared communication medium in a communication system comprising: a polling manager configured to send polling messages to the stations in accordance with a polling pattern; a transmitter coupled to the polling manager configured to accept the polling messages from the polling manager and to transmit the messages over the shared communication medium to the stations; and a receiver coupled to the polling manager configured to receive messages over the shared communication medium from the stations and to provide monitoring information to the polling manager; wherein the polling manager is configured to adapt the polling pattern including adapting a rate of polling associated with each of the stations in accordance with the monitoring information and the quality of service requirements of communication sessions at the stations by reducing a rate of polling for a session in response to the monitored transmissions for that session corresponding to a reduction in actual rate of transmission for that session, and increasing a rate of polling for a session in response to the monitored transmissions for that session corresponding to an increase in actual rate of transmission for that session. 27. The apparatus of claim 26 further comprising a resource manager coupled to the polling manager configured to accept requests to admit communication sessions and to provide resource allocations for admitted sessions to the polling manager. 28. In a communication system in which a plurality of stations share access to a communication network according to a multiple-access media access control protocol, a method for controlling access by the stations to said network comprising: at an arbiter station that is coupled to the communication network, determining a polling pattern for polling the plurality of stations including reducing a rate of polling for a station in response to monitored transmissions for that session corresponding to a reduction in actual rate of transmission for that station, and increasing a rate of polling for a station in response to the monitored transmissions for that session corresponding to an increase in actual rate of transmission for that station, wherein the rate of polling for a station satisfies quality of service requirements for a plurality of communication sessions at the station; transmitting polling messages from the arbiter station to each of the plurality of communication stations according to the polling pattern; receiving the polling messages at the plurality of stations; and at each of the plurality of stations, using the received polling messages to determine times when to transmit onto the communication network, and at said determined times transmitting data onto the communication network using the multiple access media access control protocol. 29. The method of claim 28 further comprising, at each of the plurality of stations, providing a software interface to a network layer protocol module, and accepting messages over said software interface from the network layer protocol module, and wherein determining the times when to transmit onto the communication network includes determining times when to transmit said messages accepted over said software interface. 30. The method of claim 29 wherein transmitting data onto the communication network includes transmitting the accepted messages using an Ethernet protocol. 31. The method of claim 30 wherein the network layer protocol module includes an Internet Protocol (IP) module.