Adaptive media control

• US 6,049,549 A
• Filed: 08/14/1997
• Issued: 04/11/2000
• Est. Priority Date: 08/14/1997
• Status: Expired due to Term

• Current Assignee: University Of Massachusetts
• Original Assignee: University Of Massachusetts
• Inventors: Ganz, Aura, Ganz, Zvi, Kim, Ilwhan
• Primary Examiner(s): Ton, Dang
• Application Number:
  US08/907,812
• Time in Patent Office: 971 Days
• Field of Search: 370/389, 370/395, 370/229, 370/230, 370/231, 370/232, 370/233, 370/234, 370/235, 370/468, 370/445, 370/447, 370/449, 370/460, 370/241, 370/245, 370/252, 370/480, 370/465 , 370/401, 370/441, 370/442, 370/237, 370/443, 370/448, 370/458, 370/461, 370/462, 370/464, 370/450, 370/452, 340/825.5, 340/825.08, 340/825.51, 340/825.52, 359/135, 359/136, 359/139
• US Class Current: 370/449
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/543 based on requested quality, e.g. QoS
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

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.

Claims

1. A method for media access control in a communication network which includes a plurality of communication stations which communicate over a shared communication medium and which supports a quality of service class of communication sessions such that sessions in that class have data rate requirements, comprising:

assigning communication resources including data rates in accordance with the data rate requirements of a plurality of sessions in the quality of service class including optimizing a utility function subject to a set of constraints;

polling the stations to transmit data over the shared communication medium for particular ones of the plurality of sessions according to a polling sequence;

monitoring data transmitted by the stations in response to the polling; and

adaptively allocating the communication resources in accordance with the monitored data transmissions including adapting the polling sequence;

wherein the data rate requirements include minimum required and maximum desired data rates for the plurality of sessions in the quality of service class, the utility function depends on the assigned rates, and the set of constraints includes the assigned rate for each admitted session being in a range from its minimum required data rate to its maximum desired data rate and the assigned data rates taken together not exceeding an available communication capacity.

2. A method for media access control in a communication network which includes a plurality of communication stations which communicate over a shared communication medium and which supports a quality of service class of communication sessions such that sessions in that class have data rate requirements, comprising:

assigning communication resources including data rates in accordance with the data rate requirements of a plurality of sessions in the quality of service class;

polling the stations to transmit data over the shared communication medium for particular ones of the plurality of sessions according to a polling sequence;

monitoring data transmitted by the stations in response to the polling; and

adaptively allocating the communication resources in accordance with the monitored data transmissions including adapting the polling sequence;

wherein polling the stations includes polling sessions with lower assigned data rates less frequently than stations with higher assigned data rates.

3. A method for media access control in a communication network which includes a plurality of communication stations which communicate over a shared communication medium and which supports a quality of service class of communication sessions such that sessions in that class have data rate requirements, comprising:

assigning communication resources in accordance with the data rate requirements of a plurality of sessions in the quality of service class;

polling the stations to transmit data over the shared communication medium for particular ones of the plurality of sessions according to a polling sequence;

monitoring data transmitted by the stations in response to the polling; and

adaptively allocating the communication resources in accordance with the monitored data transmissions including adapting the polling sequence;

wherein adapting the polling sequence includes reducing the rate of polling for a session in response the monitored transmissions for that session corresponding to a reduction in actual rate of transmission for that session, and increasing the rate of polling for a session in response the monitored transmissions for that session corresponding to an increase in actual rate of transmission for that session.

4. A method for media access control in a communication network which includes a plurality of communication stations which communicate over a shared communication medium and which supports a quality of service class of communication sessions such that sessions in that class have data rate requirements, comprising:

assigning communication resources in accordance with the data rate requirements of a plurality of sessions in the quality of service class;

polling the stations to transmit data over the shared communication medium for particular ones of the plurality of sessions according to a polling sequence;

monitoring data transmitted by the stations in response to the polling; and

adaptively allocating the communication resources in accordance with the monitored data transmissions including adapting the polling secruence;

wherein polling is performed in a periodic cycle and during each period of the cycle a subset of the sessions in the quality of service class are polled in accordance with their allocated communication resources, and the polling sequence is determined by the values of a plurality of state variables, each associated with a corresponding session, and adapting the polling sequence is effected by changing the values of the state variable.

5. An apparatus for polling a plurality of stations configured to communicate over a shared communication medium in a communication network comprising:

a polling manager which sends polling messages to the stations in the network in accordance with a polling sequence;

a transmitter which accepts polling messages from the polling manager and transmits the messages over the shared communication medium to the stations; and

a receiver which receives messages over the shared communication medium from the stations and provides monitoring information to the polling manager;

a resource manager which accepts requests to admit communication sessions and provides resource allocations for admitted sessions to the polling manager; and

a plurality of state indices associated with corresponding admitted sessions;

wherein the polling manager adapts the polling sequence in accordance with the monitoring information, and initializes the state indices in accordance with the resource allocations, updates the state indices in accordance with the monitoring information, and determines the polling sequence in accordance with the state indices.

6. Software stored in a computer readable medium for causing a computer, which is coupled to a plurality of communication stations which communicate over a shared communication medium in a communication network, to perform the functions:

assigning communication resources including data rates in accordance with data rate requirements of a plurality of sessions in a quality of service class including optimizing a utility function subject to a set of constraints;

polling the stations to transmit data over the shared communication medium for particular ones of the plurality of sessions according to a polling sequence;

monitoring data transmitted by the stations in response to the polling; and

adaptively allocating the communication resources in accordance with the monitored data transmissions including adapting the polling sequence;

wherein the data rate requirements include minimum required and maximum desired data rates for the plurality of sessions in the quality of service class, the utility function depends on the assigned rates, and the set of constraints includes the assigned rate for each admitted session being in a range from its minimum required data rate to its maximum desired data rate and the assigned data rates taken together not exceeding an available communication capacity.

7. Software stored in a computer readable medium for causing a computer, which is coupled to a plurality of communication stations which communicate over a shared communication medium in a communication network, to perform the functions:

assigning communication resources including data rates in accordance with data rate requirements of a plurality of sessions in a quality of service class including optimizing a utility function subject to a set of constraints;

polling the communication stations to transmit data over the shared communication medium for particular ones of the plurality of sessions according to a polling sequence;

monitoring data transmitted by the stations in response to the polling; and

adaptively allocating the communication resources in accordance with the monitored data transmissions including adapting the polling sequence;

wherein polling the stations includes polling sessions with lower assigned data rates less frequently than stations with higher assigned data rates.

8. Software stored in a computer readable medium for causing a computer, which is coupled to a plurality of communication stations which communicate over a shared communication medium in a communication network, to perform the functions:

assigning communication resources in accordance with the data rate requirements of a plurality of sessions in the quality of service class;

polling the stations to transmit data over the shared communication medium for particular ones of the plurality of sessions according to a polling sequence;

monitoring data transmitted by the stations in response to the polling; and

adaptively allocating the communication resources in accordance with the monitored data transmissions including adapting the polling sequence;

wherein adapting the polling sequence includes reducing the rate of polling for a session in response the monitored transmissions for that session corresponding to a reduction in actual rate of transmission for that session, and increasing the rate of polling for a session in response the monitored transmissions for that session corresponding to an increase in actual rate of transmission for that session.

9. Software stored in a computer readable medium for causing a computer, which is coupled to a plurality of communication stations which communicate over a shared communication medium in a communication network, to perform the functions:

assigning communication resources in accordance with the data rate requirements of a plurality of sessions in the quality of service class;

polling the stations to transmit data over the shared communication medium for particular ones of the plurality of sessions according to a polling sequence;

monitoring data transmitted by the stations in response to the polling; and

adaptively allocating the communication resources in accordance with the monitored data transmissions including adapting the polling sequence;

wherein polling is performed in a periodic cycle and during each period of the cycle a subset of the sessions in the quality of service class are polled in accordance with their allocated communication resources, and the polling sequence is determined by the values of a plurality of state variables, each associated with a corresponding session, and adapting the polling sequence is effected by changing the values of the state variable.