High reliability access point for wireless local area network

• US 5,546,397 A
• Filed: 05/04/1994
• Issued: 08/13/1996
• Est. Priority Date: 12/20/1993
• Status: Expired due to Term

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Norand Corporation (Baker Hughes Company)
• Inventors: Mahany, Ronald L.
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US08/238,180
• Time in Patent Office: 832 Days
• Field of Search: 455/52.1, 455/52.2, 455/53.1, 455/54.1, 455/56.1, 455/101, 455/103, 455/132, 455/133, 455/271, 455/277.1, 455/277.2, 370/18, 370/26, 370/37, 370/85.1, 370/85.3, 370/95.1, 370/95.3, 371/68.2, 375/260, 375/285, 375/347, 359/113, 359/152, 359/164, 359/167
• US Class Current: 370/310
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

A high reliability access point for RF communications in a wireless local area network. The high reliability access point includes a central processing unit (CPU) for handling high level protocol functions and for interfacing with the infrastructure of the local area network. The high reliability access point also includes at least two wireless adapters. Each wireless adapter includes a radio, a media access control (MAC) processor for handling low level protocol functions, and at least one antenna. The multiple wireless adapters allow the access point to perform self monitoring, reduce the effects of multipath interference, reduce some occurrences of collisions at the access point and provide infrastructure backup in the event of an infrastructure failure. The access points also allow for wireless network infrastructure communication for connection of one or more remote access points to the infrastructure. A backup power supply for the access point is also shown.

Claims

1. A high reliability access point for use in a wireless local area network, comprising:

at least two wireless adapters wherein each adapter includes an RF radio, control processor means for handling low level protocol for said wireless adapter and antenna means operably connected to said adapter for transceiving radio signals; and

central processing unit means operably connected to each of said wireless adapters for controlling high level communication protocol for said high reliability access point.

2. The high reliability access point of claim 1 including:

means operably connected to said central processing means for connecting said high reliability access point to a wired local area network distribution system, said distribution system including a host network; and

wherein said central processing unit means includes means for interfacing said central processor unit means with said host network.

3. The high reliability access point of claim 1 wherein said antenna means for at least one of said wireless adapters comprises two antennas providing an antenna diversity function.

4. The high reliability access point of claim 1 wherein said control processor means for said wireless adapters comprises a media access control (MAC) processor.

5. The high reliability access point of claim 3 wherein said control processor means for said wireless adapter with said two antennas includes means for determining which of said two antennas is receiving the better signal.

6. The high reliability access point of claim 1:

wherein said control processor means for each of said wireless adapters includes means for quantifying the signal quality of the signal received on said antenna means;

wherein said control processor means for each of said wireless adapters includes means for transmitting said signal quality information to said central processing unit means; and

wherein said central processing unit means includes means for comparing said signal qualities for each of said wireless adapters whereby the central processing unit means can utility the wireless adapter with the best signal.

7. The high reliability access point of claim 2 wherein said central processing unit means includes means for assigning addresses to each of said wireless adapters.

8. The high reliability access point of claim 7 wherein each of said wireless adapters are assigned the same address whereby the wireless adapters operate in a similar and simultaneous manner.

9. The high reliability access point of claim 7 wherein at least two of said wireless adapters are assigned different addresses and operate on different channels or on different frequency hopping sequences.

10. The high reliability access point of claim 8 wherein said central processing unit means includes means for selectively choosing which wireless adapter to receive incoming RF transmission whereby said central processing unit means will select the wireless adapter with the highest quality signal reception.

11. The high reliability access point of claim 10 wherein said central processing unit means includes means for utilizing wireless adaptor selected incoming RF transmission to transmit responsive outgoing RF transmission.

12. The high reliability access point of claim 8 wherein said central processing unit means includes means for using the multiple wireless adapters with the same address to reduce the occurrence of collisions when two or more RF transmissions are received at the access point at the same time.

13. The high reliability access point of claim 9 wherein said central processing unit means includes means for dedicating one of said wireless adapters for communication with another access point.

14. The high reliability access point of claim 13 wherein said central processing unit means includes means for detecting a break in the wired local area network distribution system.

15. The high reliability access point of claim 14 wherein said central processing unit means includes means for indicating to the host network that a break has occurred in the infrastructure.

16. The high reliability access point of claim 1:

wherein said central processing unit means includes means for initiating an RF transmission over one of said wireless adapters; and

wherein said central processing unit means includes means for listening to said initiated RF transmission using one of said remaining wireless adapters.

17. The high reliability access point of claim 16:

wherein said central processing unit means includes means for detecting when a wireless adapter is malfunctioning; and

wherein said central processing unit means includes means for excluding said malfunctioning wireless adapter from being used.

18. The high reliability access point of claim 17 wherein said central processing unit means includes means for indicating to the host network that a wireless adapter at the access point is malfunctioning.

19. The high reliability access point of claim 8:

wherein two of said wireless adapters receive the same transmitted RF signal;

wherein said central processing unit means includes means for comparing the information received by said two of said wireless adapters; and

wherein said central processing unit means includes means for utilizing said compared information to detect when a wireless adapter is receiving information incorrectly.

20. The high reliability access point of claim 19 wherein said central processing unit means includes means for indicating to the system management that a wireless adapter at the access point is malfunctioning.

21. The high reliability access point of claim 2 further including a back-up power source.