Determination of link qualities between an access point and a plurality of clients

• US 8,055,759 B2
• Filed: 09/18/2006
• Issued: 11/08/2011
• Est. Priority Date: 09/18/2006
• Status: Active Grant

• Current Assignee: Hitachi Energy Limited
• Original Assignee: Tropos Networks Incorporated (ABB Limited)
• Inventors: Gupta, Mukesh, Srikrishna, Devabhaktuni
• Primary Examiner(s): Nguyen; Dustin
• Application Number:
  US11/522,882
• Publication Number:
  US 20080071919A1
• Time in Patent Office: 1,877 Days
• Field of Search: 370/349, 370/352, 370/248, 370/395.2, 370/329, 370/338, 455/456.1, 455/439, 709/242
• US Class Current: 709/224
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 60/04 using triggered events

Abstract

An apparatus and method of determining link qualities of a plurality of links between an access point and a plurality of client devices is disclosed. The method includes detecting all client devices associated with the access point. A list of the associated client devices is generated. The access point transmits keep alive packets according to the list. The access point counts responds to the keep alive packets from each of the client devices. The access point estimates a link quality between the access point and each client device based on the counted responses. An apparatus and method of determining link qualities of a plurality of links between an access node of a wireless mesh network and a plurality of client devices is also disclosed. The method includes detecting all client devices associated with the access node. A list of the associated client devices is generated. The access node transmits keep alive packets to each of the associated client devices according to the list. The access point counts responds to the keep alive packets from each of the client devices. The access point estimates a link quality between the access point and each client device based on the counted responses.

Claims

1. A method of determining link qualities of a plurality of links between an access point and a plurality of client devices, comprising:

detecting all client devices associated with the access point, wherein detecting a client device comprises the access point performing a request and response exchange with the client device;

generating a list of the associated client devices;

the access point transmitting keep alive packets to each of the associated client devices according to the list;

the access point counting responses to the keep alive packets from each of the client devices; and

the access point estimating a link quality of a wireless link between the access point and each client device based on the counted responses;

wherein

the estimates of link quality are based on a packet success probability as determined by a percentage of keep alive packets sent to each client device that result in a response received by the access point from the client device.

2. The method of claim 1, wherein the keep alive packets are transmitted one at a time.

3. The method of claim 1, wherein the list is ordered.

4. The method of claim 1, wherein the access point transmits the keep alive packets randomly from the list.

5. The method of claim 1, wherein the access point transmits the keep alive packets at a predetermined rate.

6. The method of claim 1, wherein the keep alive packets are ARP packets.

7. The method of claim 1, wherein the keep alive packets are ICMP echo packets.

8. The method of claim 1, further comprising communicating the link qualities to a system operator.

9. The method of claim 1, further comprising:

updating the list as new client devices are detected and old client devices are no longer detected.

10. The method of claim 9, wherein the list is updated by adding new clients at either end of the list.

11. The method of claim 9, wherein the list is updated by deleting old client devices while essentially maintaining the ordered list.

12. A method of determining link qualities of a plurality of links between an access node of a wireless mesh network and a plurality of client devices, comprising:

detecting all client devices associated with the access point, wherein detecting a client device comprises the access point performing a request and response exchange with the client device;

generating a list of the associated client devices;

the access node transmitting keep alive packets to each of the associated client devices according to the list;

the access node counting responses to the keep alive packets from each of the client devices; and

the access node estimating a link quality of a wireless link between the access node and each client device based on the counted responses;

wherein

the estimates of link quality are based on a packet success probability as determined by a percentage of keep alive packets sent to each client device that result in a response received by the access node from the client device.

13. The method of claim 12, wherein the access node transmits the keep alive packets at a predetermined rate.

14. The method of claim 12, wherein the list is ordered.

15. The method of claim 12, wherein the access node transmits the keep alive packets randomly from the list.

16. The method of claim 12, further comprising communicating the link qualities to a system operator.

17. The method of claim 12, further comprising:

updating the list as new client devices are detected and old client devices are no longer detected.

18. The method of claim 12, wherein the access node is a gateway of the wireless mesh network.

19. An access point including processor and memory, the access point operative to:

detect all client devices associated with the access point, wherein detecting a client device comprises the access point performing a request and response exchange with the client device;

generate a list of the associated client devices;

transmit keep alive packets to each of the associated client devices according to the list;

count responses to the keep alive packets from each of the client devices; and

estimate a link quality of a wireless link between the access point and each client device based on the counted responses;

wherein the estimates of link quality are based on a packet success probability as determined by a percentage of keep alive packets sent to each client device that result in a response received by the access point from the client device.