ANTENNA DIVERSITY TO IMPROVE PROXIMITY DETECTION USING RSSI

• US 20100159840A1
• Filed: 12/18/2008
• Published: 06/24/2010
• Est. Priority Date: 12/18/2008
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Plantronics, Inc.
• Inventors: Rosener, Douglas K., Brown, William O.
• Granted Patent: US 8,340,614 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: G01S 11/06 using intensity measurements
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 7/08 at the receiving station
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and apparatus for determining proximity of a mobile radio relative to its base radio. Antenna diversity is utilized to provide improved proximity detection, such as NEAR state or FAR state, of the mobile radio relative to its base radio.

Claims

1. A method for determining a near state or a far state of a mobile radio in relation to a base radio comprising:

measuring a first RSSI signal using a first antenna associated with a base radio;

measuring a second RSSI signal using a second antenna associated with the base radio;

generating a first state indication utilizing the first RSSI signal comprising a first near state indication or a first far state indication;

generating a second state indication utilizing the second RSSI signal comprising a second near state indication or a second far state indication;

generating a third state indication comprising a third near state indication or a third far state indication responsive to comparing the first state indication to the second state indication.

2. The method of claim 1, wherein generating a third state indication further comprises comparing the first state indication and the second state indication to a prior state indication.

3. The method of claim 1, wherein the third state indication comprises a third near state indication where the first state indication comprises a first near state indication and the second state indication comprises a second near state indication, and the third state indication comprises a third far state indication where the first state indication comprises a first far state indication and the second state indication comprises a second far state indication.

4. The method of claim 1, wherein measuring a first RSSI signal and measuring a second RSSI signal comprises receiving the first RSSI signal and the second RSSI signal in a Bluetooth system, IEEE 802.11 system, or DECT system.

5. The method of claim 1, wherein generating a first state indication utilizing the first RSSI signal comprises comparing the first RSSI signal to a near/far threshold RSSI value, and generating a second state indication utilizing the second RSSI signal comprises comparing the second RSSI signal to the near/far threshold RSSI value.

6. The method of claim 5, wherein the near/far threshold RSSI value is a value above which a mobile radio is in a near state and below which the mobile radio is in a far state.

7. The method of claim 1, wherein generating a first state indication comprises employing a hysteresis to prevent rapid toggling between a first near state indication and first far state indication, and generating a second state indication comprises employing a hysteresis to prevent rapid toggling between a second near state indication and a second far state indication.

8. The method of claim 1, wherein the base radio is coupled to a personal computer via a computer interface.

9. The method of claim 8, wherein the computer interface is a USB interface.

10. The method of claim 1, wherein the first antenna and the second antenna are diverse in space, radiation pattern, or polarization.

11. The method of claim 1, wherein generating a first state indication utilizing the first RSSI signal further comprises a first unknown state indication and generating a second state indication utilizing the second RSSI signal further comprises a second unknown state indication.

12. A wireless device, comprising:

a first antenna;

a second antenna;

an antenna switch for switching between the first antenna and the second antenna;

a wireless transceiver for sending and receiving signals using the first antenna or the second antenna;

a processor; and

a computer readable memory storing a first set of instructions that when executed by the processor cause the wireless device to receive a first signal using the first antenna and receive a second signal using the second antenna, and a second set of instructions that when executed by the processor generate a near state indication or a far state indication utilizing a first signal RSSI and a second signal RSSI.

13. The wireless device of claim 12, further comprising a network interface.

14. The wireless device of claim 13, wherein the network interface comprises an interface to a public switched telephone network, integrated services digital network, local area network, or wireless local area network.

15. The wireless device of claim 12, wherein the wireless transceiver comprises a DECT transceiver, Bluetooth transceiver, or IEEE 802.11 transceiver.

16. The wireless device of claim 12, further comprising a computer interface.

17. The wireless device of claim 12, further comprising:

a base housing; and

a conductor cable extending away from the base housing and coupled to the second antenna, wherein the second antenna is at a distance from the base housing.

18. The wireless device of claim 12, wherein the first antenna and the second antenna are diverse in space, radiation pattern, or polarization.

19. The wireless device of claim 12, wherein the near state indication or the far state indication is generated by comparing the first signal RSSI and the second signal RSSI to a near/far threshold RSSI.

20. The wireless device of claim 19, wherein the near/far threshold RSSI is a value above which a headset is in a near state and below which the headset is in a far state.

21. A wireless device comprising:

a first antenna to receive a first signal from a second wireless device;

a wireless transceiver to send and receive signals using the first antenna or the second antenna;

a near/far state determination module for generating a near state indication or a far state indication by comparing a first signal RSSI and a second signal RSSI to a near/far threshold RSSI.

22. The wireless device of claim 21, further comprising a computer interface to couple the wireless device to a computer.

23. The wireless device of claim 21, further comprising a network interface to couple the wireless device to a communications network.

24. The wireless device of claim 21, further comprising:

a housing for storing the first antenna, the wireless transceiver, and the near/far state determination module; and

a cable extending away from the housing, the cable coupled to the second antenna for placing the second antenna at a distance from the housing.