Method and apparatus for selecting a directional antenna in a wireless communication system

• US 6,445,688 B1
• Filed: 08/31/2000
• Issued: 09/03/2002
• Est. Priority Date: 08/31/2000
• Status: Expired due to Term

• Current Assignee: Monument Bank of Intellectual Property, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Ricochet Networks, Inc. (Proxim Wireless Corporation)
• Inventors: Rayala, Padmasheela, Khelghati, Hojat, Garces, Rodrigo
• Primary Examiner(s): NGO, RICKY QUOC
• Application Number:
  US09/652,858
• Time in Patent Office: 733 Days
• Field of Search: 370/328, 370/329, 370/331, 370/332, 370/333, 370/334, 370/338, 370/339, 370/401, 370/465, 342/367, 342/368, 342/417, 342/423, 342/437, 375/267, 375/299, 455/25, 455/67.1, 455/101, 455/102, 455/115
• US Class Current: 370/334
• CPC Class Codes: H04B 7/0608 Antenna selection according to transmission parameters
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow
• CPC Class Codes: H04W 40/06 based on characteristics of available antennas

Abstract

A method and a system are provided to determine and thus select the best choice for antenna to be used by a network device having a plurality of directional antennas for a particular sending source. The determination is made using on a metric based on the success rate of packets received at a particular directional antenna from the sending source and secondarily on a received signal strength indicator. The determination is stored and made available for processing such that a router is able to request communication through a device with a destination via the second wireless communication device without knowledge of the best antenna match. In a specific method the first communication device broadcasts packets, via each associated directional antenna, to query for the existence of the second wireless communication devices. The first device then receives a plurality of information packets about existence of the second wireless communication devices in response to the broadcast packets or in response to a query about third parties. As between each directional antenna and each second wireless communication device, a packet success metric is determined for each directional antenna, which becomes the basis for antenna selection.

Claims

1. In a wireless communication system having a plurality of directional antennas associated with a first communication device at a first site, a router for targeting a destination via an indeterminate path including said first site, at least one second wireless communication device at a second site, a method for selecting a best antenna from said plurality of directional antennas for said first wireless communication device for communicating with each said second wireless communication device, the method comprising:

causing said first communication device to broadcast packets, via each said directional antenna, to query for existence of said second wireless communication devices;

receiving a plurality of information packets about existence of said second wireless communication devices in response to said broadcast packets or in response to a query about third parties;

thereafter

as between each said directional antenna and each second wireless communication device, determining a packet success metric for each said directional antenna;

comparing packet success metrics with each other to determine a best match of directional antenna with each second wireless communication device; and

storing at said first site said best match such that said router is able to request communication through said first device with said destination via said second wireless communication device without knowledge of said match.

2. The method of claim 1 wherein the packet success metric is a Packet Success Rate (PSR).

3. The method of claim 1 further including exchanging a Channel Quality Measurement (CQM) packet between each said directional antenna and said second wireless communication devices for reporting channel quality.

4. The method of claim 1 wherein the plurality of directional antennas comprises four directional antennas oriented to have substantially 360 degrees horizontal antenna coverage.

5. The method of claim 3 wherein the comparing step further comprises:

if there is one possible largest packet success metric, selecting the largest packet success metric as the best metric;

or

if there is a plurality of identical possible largest packet success metrics, selecting as the best metric that metric associated with a best Received Signal Strength Indication (RSSI) value determined during a communication session involving said Channel Quality Measurement packets.

6. The method of claim 1 further comprising storing the best metric memory at said first communication device only when the best metric exceeds a threshold value.

7. A method for selecting a best antenna from a plurality of directional antennas at a remote device for communicating with a wireless access device at a wired access point having a plurality of wireless access devices, wherein the remote device and the wireless access device belong to a path determined by a router, the method comprising:

sending a plurality of synchronization packets and receiving a response from the wireless access device at the wired access point to determine the presence of wireless access devices at the wired access point;

if a memory of the remote device, includes a stored RSSI associated with the wireless access device, obtaining a new RSSI associated with the wireless access device; and

comparing the stored RSSI with the new RSSI to determine if the stored best antenna is the best antenna for the wireless access device, wherein the determination being made independently of the router.

8. The method of claim 7 wherein the sending the plurality of synchronization packets is over a plurality of frequency hopping channels.

9. A system for selecting the best antenna at a remote device of a plurality of remote devices for communicating with a wireless access device of a wired access point of a plurality of wireless access devices, wherein each wireless access device comprises, a wireless communication link for communication to the remote device and a wired communication link to a wired network, the system comprising:

means for sending a plurality of information packets from the wireless access device to the remote device; and

the remote device, comprising a processor, a memory, and a plurality of directional antennas for receiving the plurality of information packets, wherein the memory has stored software comprising;

a signal quality evaluation module for determining a first quality metric for each said directional antenna from the information packets received for that antenna; and

an antenna selection module for selecting, based on the first quality metric, the best antenna for the wireless access device.

10. The system of claim 9 wherein the sending includes using a plurality of frequency hopping channels.

11. The system of claim 9 further comprising:

a flash memory for storing the best directional antenna for communicating to the wireless access device, when the best quality metric associated with the best directional antenna is above a threshold value.

12. The system of claim 9 wherein the first quality metric includes a packet success rate.

13. The system of claim 9 wherein the signal quality evaluation module further includes a second quality metric for each directional antenna, said second quality metric based on a received signal strength indicator.

14. The system of claim 13 wherein the antenna selection module further employs the second quality metric.

15. The system of claim 9 wherein the stored software further comprises a retry module when the first quality metric cannot be determined.

16. In a wireless communication system having a plurality of directional antennas associated with a first communication device at a first site, a router for targeting a destination via an indeterminate path including said first site, at least one second wireless communication device at a second site, a computer program product for selecting a best antenna from said plurality of directional antennas for said first wireless communication device for communicating with each said second wireless communication device, the method comprising:

code for causing said first communication device to broadcast packets, via each said directional antenna, to query for existence of said second wireless communication devices;

code for receiving a plurality of information packets about existence of said second wireless communication devices in response to said broadcast packets or in response to a query about third parties;

thereafter

code for as between each said directional antenna and each second wireless communication device, determining a packet success metric for each said directional antenna;

code for comparing packet success metrics with each other to determine a best match of directional antenna with each second wireless communication device;

code for storing at said first site said best match such that said router is able to request communication through said first device with said destination via said second wireless communication device without knowledge of said match; and

a computer readable storage medium for storing the codes.