Wireless LAN with load balancing

• US 20020110105A1
• Filed: 05/17/2001
• Published: 08/15/2002
• Est. Priority Date: 05/19/2000
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Kamerman, Adriaan, Awater, Geert Arnout, Moelard, Hendrik
• Granted Patent: US 7,173,918 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 36/304 due to measured or perceived resources with higher communication quality
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

Abstract

A communication system with a plurality of access points (AP1, AP2, AP3) and at least one network station (5, 6), the network station (5, 6) being arranged to communicate with one of said plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, each access point (AP1, AP2, AP3) is able to:

monitor its access point traffic load and

transmit an access point traffic load parameter (ATT) to the network station (5, 6), and the network station (5, 6) is able to:

monitor its network station traffic load;

store a network station traffic load parameter (AUTT);

receive access point traffic load parameters (ATT) from the access points (AP1, AP2, AP3);

select a communication connection with one of the access points (AP1, AP2, AP3) using a predetermined cost function taking the access point traffic load parameters (ATT) and the network station traffic load parameters (AUTT) into account.

Claims

1. A communication system comprising a plurality of access points (AP1, AP2, AP3) and at least one network station (5, 6), said at least one network station (5, 6) being arranged to communicate with one of said plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, wherein each of said plurality of access points (AP1, AP2, AP3) is arranged to:

monitor its access point traffic load and

transmit an access point traffic load parameter (ATT) indicative of said access point traffic load to said at least one network station (5, 6),

and said at least one network station (5, 6) is arranged to;

monitor its network station traffic load;

store a network station traffic load parameter (AUTT) indicative of said network station traffic load;

receive access point traffic load parameters (ATT) from said plurality of access points (AP1, AP2, AP3);

select a communication connection with one of said plurality of access points (AP1, AP2, AP3) using a predetermined cost function taking at least said access point traffic load parameters (ATT) and said network station traffic load parameters (AUTT) into account.

2. A system according to claim 1, wherein each of said plurality of access points is arranged to determine its access point traffic load parameter by monitoring its transmission and reception time load averaged over time.

3. A system according to claim 2, wherein each of said plurality of access points is arranged to transmit its access point traffic load parameter in an additional data frame within a beacon and probe response frame.

4. A system according to any of the claim 3, wherein each of the plurality of access points (AP1, AP2, AP3) is also arranged to:

monitor its communication quality with said at least one network station (5, 6), and

to transmit an access point communication quality parameter (NLAP) indicative of said communication quality to said at least one network station (5, 6);

and said at least one network station (5, 6) is arranged to;

receive said access point communication quality parameter (NLAP) from a predetermined access point,

determine during reception of signals a network station communication quality parameter (NLST) indicative of the communication quality for said network station (5, 6) with said predetermined access point,

select the largest of said communication quality parameters (NLAP, NLST) as a minimum communication quality parameter (ANL),

select a communication connection with one of said plurality of access points (AP1, AP2, AP3) using said predetermined cost function taking also said minimum communication quality parameter (ANL) into account.

5. A system according to claim 4, wherein said access point communication quality parameter is calculated as average noise level (NLAP), said network station communication quality parameter is calculated as average noise level (NLST), and said minimum communication quality parameter is calculated as average noise level (ANL).

6. A system according to any claim 1, wherein said at least one network station (5, 6) is arranged to determine its network station traffic load parameter by monitoring its transmission and reception time load averaged over time (AUTT).

7. A system according to claim 1, wherein said at least one network station (5, 6) monitors its signal reception level (SRL) and is arranged to select a communication connection with one of said plurality of access points (AP1, AP2, AP3) using said predetermined cost function taking also said signal reception level (SRL) into account.

8. A system according to claim 1, wherein said cost function uses a weight factor to modify relative weight of said access point traffic load parameter (ATT).

9. A system according to claim 8, wherein said weight factor is also used to modify relative weight of said network station traffic load parameter (AUTT).

10. A system according to claim 8, wherein said weight factor has a value in dependence on scan state of said at least one network station (5, 6).

11. A system according to claim 10, wherein said scan state is either one of the following states:

connected scan state, searching scan state, or out-of-range scan state.

13. An access point according to claim 12, arranged to determine its access point traffic load parameter by monitoring its transmission and reception time load averaged over time.

14. An access point according to claim 12, wherein said access point is arranged to transmit its access point traffic load parameter in an additional data frame within a beacon and probe response frame.

15. An access point according to claim 12, wherein the access point (AP1, AP2, AP3) is also arranged to:

monitor its communication quality with said at least one network station (5, 6), and

to transmit an access point communication quality parameter (NLAP) indicative of said communication quality to said at least one network station (5, 6).

16. An access point according to claim 15, wherein said access point communication quality parameter is average noise level (NLAP).

18. A network station (5, 6) according to claim 17, arranged to receive from said predetermined access point from said plurality of access points (AP1, AP2, AP3) an access point communication quality parameter (NLAP) indicative of the communication quality of said predetermined access point, to determine for said predetermined access point a network station communication quality parameter (NLST) indicative of the communication quality for said network station (5, 6) with said predetermined access point, to select for said predetermined access point the largest of said communication quality parameters (NLAP, NLST) as a minimum communication quality parameter (ANL), and to select a communication connection with one of said plurality of access points (AP1, AP2, AP3) using said predetermined cost function taking also said minimum communication quality parameters (ANL) into account.

19. A network station according to claim 18, wherein said access point communication quality parameter is calculated as average noise level (NLAP), said network station communication quality parameter is calculated as average noise level (NLST), and said minimum communication quality parameter is calculated as average noise level (ANL).

20. A network station according to claim 17, arranged to determine its network station traffic load parameter by monitoring its transmission and reception time load averaged over time (AUTT).

21. A network station according to claim 17, arranged to monitor its signal reception level (SRL) and to select a communication connection with one of said plurality of access points (AP1, AP2, AP3) using said predetermined cost function taking also said signal reception level (SRL) into account.

22. A network station according to claim 17, wherein said cost function uses a weight factor to modify relative weight of said access point traffic load parameter (ATT).

23. A network station according to claim 22, wherein said weight factor is also used to modify relative weight of said network station traffic load parameter (AUTT).

24. A network station according to claim 22, wherein said weight factor has a value in dependence on scan state of said at least one network station (5, 6).

25. A network station according to claim 24, wherein said scan state is either one of the following states:

connected scan state, searching scan state, or out-of-range scan state.

29. A data carrier provided with a computer program product according to claim 28.

12. An access point (AP1, AP2, AP3) arranged to communicate with at least one network station (5, 6) through a wireless communication protocol, wherein said access point (AP1, AP2, AP3) is also arranged to:

monitor its access point traffic load and

transmit an access point traffic load parameter (ATT) indicative of said access point traffic load to said at least one network station (5, 6).

17. A network station (5, 6) arranged to communicate with one of a plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, wherein said network station (5, 6) is arranged to

monitor its network station traffic load;

store a network station traffic load parameter (AUTT) indicative of said network station traffic load;

receive access point traffic load parameters (ATT) indicative of access point traffic loads from said plurality of access points (AP1, AP2, AP3);

select a communication connection with one of said plurality of access points (AP1, AP2, AP3) using a predetermined cost function taking at least said access point traffic load parameters (ATT) and said network station traffic load parameters (AUTT) into account.

26. A method in a communication system comprising a plurality of access points (AP1, AP2, AP3) and at least one network station (5, 6), for communication between said at least one network station (5, 6) and one of said plurality of access points (AP1, AP2, AP3), said at least one network station (5, 6) being arranged to communicate with one of said plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, wherein said method comprises the following steps carried out by the access points (AP1, AP2, AP3):

monitoring access point traffic loads and

transmitting access point traffic load parameters (ATT) indicative of said access point traffic loads to said at least one network station (5, 6),

and said method also includes the following steps carried out by said at least one network station (5, 6);

monitoring network station traffic load;

storing a network station traffic load parameter (AUTT) indicative of said network station traffic load;

receiving access point traffic load parameters (ATT) from said plurality of access points (AP1, AP2, AP3);

selecting a communication connection with one of said plurality of access points (AP1, AP2, AP3) using a predetermined cost function taking at least said access point traffic load parameters (ATT) and said network station traffic load parameters (AUTT) into account.

27. A method carried out by an access point (AP1, AP2, AP3) arranged to communicate with at least one network station (5, 6) through a wireless communication protocol, wherein said method comprises the following steps:

monitoring access point traffic load and

transmitting an access point traffic load parameter (ATT) indicative of said access point traffic load to said at least one network station (5, 6).

28. A computer program product to be loaded by an access point (AP1, AP2, AP3) arranged to communicate with at least one network station (5, 6) through a wireless communication protocol, wherein said computer program product allows said access point to carry out the following steps:

monitoring access point traffic load and

transmitting an access point traffic load parameter (ATT) indicative of said access point traffic load to said at least one network station (5, 6).

30. A method to be carried out by a network station (5, 6) arranged to communicate with one of a plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, wherein said method comprises the following steps:

monitoring network station traffic load;

storing a network station traffic load parameter (AUTT) indicative of said network station traffic load;

receiving access point traffic load parameters (ATT) indicative of access point traffic loads from said plurality of access points (AP1, AP2, AP3);

selecting a communication connection with one of said plurality of access points (AP1, AP2, AP3) using a predetermined cost function taking at least said access point traffic load parameters (ATT) and said network station traffic load parameters (AUTT) into account.

31. A computer program product to be loaded by a network station (5, 6) arranged to communicate with one of a plurality of access points (AP1, AP2, AP3) through a wireless communication protocol, wherein said computer program product allows said network station to carry out the following steps:

monitoring network station traffic load;

storing a network station traffic load parameter (AUTT) indicative of said network station traffic load;

receiving access point traffic load parameters (ATT) indicative of access point traffic loads from said plurality of access points (AP1, AP2, AP3);

selecting a communication connection with one of said plurality of access points (AP1, AP2, AP3) using a predetermined cost function taking at least said access point traffic load parameters (ATT) and said network station traffic load parameters (AUTT) into account.

32. A data carrier provided with a computer program product according to claim 31.