System and method for adjusting media access control parameters in a wireless network

• US 8,509,129 B2
• Filed: 06/04/2008
• Issued: 08/13/2013
• Est. Priority Date: 06/04/2008
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Deb, Budhaditya, Hartman, Michael James, Davenport, David Michael, Grubis, Matthew George
• Primary Examiner(s): Moore, Ian N
• Assistant Examiner(s): Le, Brian T
• Application Number:
  US12/133,140
• Publication Number:
  US 20090303908A1
• Time in Patent Office: 1,896 Days
• Field of Search: 370/448
• US Class Current: 370/310
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A system for setting WLAN node operating parameters includes at least one access point (AP) radio and a plurality of nodes in wireless communication with the AP radio according to media access control (MAC) parameters. Each of the plurality of nodes has a quality of service (QoS) threshold for wireless communication with the AP radio that is a function of the MAC parameters and includes a controller configured to provide individualized control of the MAC parameters. The controller is programmed to measure current settings for at least a portion of the MAC parameters for the node, input the current settings for those MAC parameters of the node into a WLAN system model to generate a system model output, and adapt a setting of at least one of the MAC parameters for the node to meet the QoS threshold for the node based on the system model output.

Claims

1. A wireless local area network (WLAN) comprising:

at least one access point radio; and

a plurality of nodes in wireless communication with the at least one access point radio according to media access control (MAC) parameters, each of the plurality of nodes having a quality of service (QoS) threshold for wireless communication with the at least one access point radio that is a function of the MAC parameters;

wherein each of the plurality of nodes comprises a controller configured to provide individualized control of the MAC parameters corresponding to a node, the controller programmed to;

measure current settings for at least a portion of the MAC parameters for the node;

determine approximate current settings for at least a portion of the MAC parameters for remaining nodes from the plurality of nodes;

input the current settings for the at least a portion of the MAC parameters of the node and the approximate current settings for the remaining nodes into a WLAN system model to generate a system model output; and

iteratively perform a gradient descent based optimization to adapt a setting of at least one of the MAC parameters for the node till the QoS threshold for the node based on the system model output is met, wherein the QoS threshold comprises at least one of a minimum signal throughput level and a maximum signal time delay.

2. The WLAN of claim 1 wherein the adapting of the setting of the at least one MAC parameter at each iterative step in the plurality of iterative steps is based on gradient residuals of the gradient descent based optimization.

3. The WLAN of claim 1 wherein the controller is further programmed to:

perform each of the plurality of iterative steps at a first repetition rate; and

upon meeting the QoS threshold, performing the plurality of iterative steps at a second repetition rate that is temporally longer than the first repetition rate to monitor WLAN activity.

4. The WLAN of claim 1 wherein the controller is further programmed to determine the second repetition rate based on one of a pre-determined repetition rate and an update to the WLAN.

5. The WLAN of claim 1 wherein the controller is further programmed to adapt the setting of the at least one MAC parameter such that signal throughput is maximized irrespective of a number of the plurality of nodes in the WLAN.

6. The WLAN of claim 1 wherein the at least one adapted MAC parameter comprises a size of a contention window.

7. The WLAN of claim 1 wherein the at least a portion of the MAC parameters comprises a first MAC parameter and a second MAC parameter, the first MAC parameter being a measured number of MAC layer acknowledgements and the second MAC parameter being a measured number of signal retransmissions.

8. The WLAN of claim 1 wherein the plurality of nodes are in wireless communication with the at least one access point radio according to IEEE 802.11e protocol.

9. The WLAN of claim 1 wherein the meeting of the QoS threshold comprises converging the at least one MAC parameter to within a predetermined percentage of the QoS threshold.

10. The WLAN of claim 1 wherein each of the plurality of nodes comprises an indicator configured to alert a user of a convergence trend of the at least one MAC parameter for meeting the QoS threshold.

11. The WLAN of claim 1 wherein the WLAN system model comprises one of a previously computed system model and a stored lookup table.

12. The WLAN of claim 1 wherein the at least one access point radio is programmed to:

determine an amount of residual bandwidth remaining in the WLAN based on the QoS thresholds for each of the plurality of nodes; and

allow admission of an additional node into the WLAN if the amount of residual bandwidth remaining supports admission of the additional node.

13. A method for selecting a plurality of operating parameters for a node in a wireless local area network (WLAN) comprising:

deriving a local analytical model of the WLAN based on media access control (MAC) parameters and wireless signal traffic characteristics;

acquiring local measurements of a portion of the MAC parameters at the node;

determining an achieved quality of service (QoS) for the node by applying the acquired local measurements of the portion of the MAC parameters to the local analytical model; and

performing an adaptive optimization of the local analytical model using gradient based optimization; and

iteratively modifying at least one of the MAC parameters of the node based on the adaptive optimization till a QoS threshold for the node is met, wherein the QoS threshold for the node comprises at least one of a minimum signal throughput level and a maximum signal time delay.

14. The method of claim 13 wherein acquiring local measurements of a portion of the MAC parameters comprises acquiring a number of MAC layer acknowledgments and retransmissions.

15. The method of claim 13 wherein modifying at least one of the MAC parameters of the node to meet the QoS threshold comprises modifying a size of a contention window.

16. The method of claim 13 wherein the local analytical model comprises a model of IEEE 802.11e protocol.

17. A controller for a hospital network node, wherein the controller comprises at least one processor configured to carry out programmable instructions executing the steps to:

set a quality of service (QoS) requirement for a wireless signal transmission from the hospital network node, the wireless signal transmission being governed by a plurality of media access control (MAC) parameters;

generate a model of a hospital network that is based on the plurality of MAC parameters and on signal traffic characteristics of the wireless signal transmission;

receive measurements of MAC layer acknowledgements and signal retransmissions from the hospital network node;

insert the received MAC layer acknowledgements and signal retransmissions from the WLAN node into the generated model of the hospital network;

perform an adaptive optimization of the generated model using gradient-descent optimization upon insertion of the received MAC layer acknowledgements and signal retransmissions to determine a desired value for at least one of the plurality of MAC parameters that satisfies the QoS requirement for the wireless signal transmission by the hospital network node; and

modify the at least one of the plurality of MAC parameters based on the adaptive optimization to the desired value till the QoS requirement for the wireless signal transmission by the hospital network node is met, wherein the QoS requirement comprises at least one of a minimum signal throughput level and a maximum signal time delay.

18. The controller of claim 17 further programmed to converge the at least one of the plurality of MAC parameters to the desired value over a plurality of iterative steps performed in the gradient-descent based optimization.

19. The controller of claim 18 wherein the at least one of the plurality of MAC parameters converges to the desired value when the value is within a pre-determined percentage of the desired value.

20. The controller of claim 17 further programmed to determine a contention window size to satisfy the QoS requirement for the wireless signal transmission from the WLAN node.

21. The controller of claim 17 further programmed to activate at least one of a visual alert indicator and an audible alert indicator if the QoS requirement for the WLAN node cannot be met based on a network condition of the WLAN.