APPARATUS FOR AND METHOD OF BLUETOOTH AND WIRELESS LOCAL AREA NETWORK COEXISTENCE USING A SINGLE ANTENNA IN A COLLOCATED DEVICE

• US 20090137206A1
• Filed: 11/23/2007
• Published: 05/28/2009
• Est. Priority Date: 11/23/2007
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Sherman, Itay, Tzoreff, Yaniv, Shoham, Avishai P.
• Granted Patent: US 8,045,922 B2
• Time in Patent Office: Days
• US Class Current: 455/41.200
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A novel and useful apparatus for and method of providing a mechanism for achieving coexistence between a Bluetooth system and WLAN system collocated in the same communications device such as a mobile terminal. The coexistence mechanism of the present invention functions to monitor WLAN and Bluetooth system activity, determine the access priority of both WLAN and Bluetooth systems, predict Bluetooth high priority packet transmission patterns, allocate bandwidth to both the Bluetooth and WLAN systems in accordance with the traffic patterns predicted, and switch the antenna and control the Bluetooth and WLAN power amplifiers when required.

Claims

1. A method of detecting a Bluetooth high priority period, said method comprising the steps of:

providing a first array containing differences between short duration Bluetooth high priority transactions;

providing a second array containing differences between long duration Bluetooth high priority transactions;

determining the difference in frames between a current transaction and a previous transaction;

adding said difference to either said first or second arrays in accordance therewith;

comparing said difference to differences previously stored in said first and second arrays and declaring an active period if the number of matches exceed a threshold; and

setting the duration of said current transaction in accordance with the duration measured in said previous transaction.

2. The method according to claim 1, wherein said step of adding comprises adding said difference to said first array if the difference is within a first predetermined range.

3. The method according to claim 1, wherein said step of adding comprises adding said difference to said second array if the difference is within a second predetermined range.

4. The method according to claim 1, wherein said active period is declared for said first array if four differences therein either have a value equal to a prioritized period or have the same value.

5. The method according to claim 1, wherein said active period is declared for said second array if either four differences therein have a value equal to a prioritized period or five differences therein have the same value.

6. The method according to claim 1, further comprising the step of performing a trace on said active period, checking whether each sample of a current transaction occurred in a predicted time.

7. The method according to claim 1, further comprising the step of synchronizing prediction timing to a Bluetooth frame clock in each sample of a detected period.

8. The method according to claim 6, further comprising the step of canceling said active period if said tracing determines a predicted period has not occurred.

9. The method according to claim 1, further comprising the step of canceling said active period if there is no new value in either said first or second arrays for a predetermined time period.

10. A method of coexistence in a communications device incorporating a wireless local area network (WLAN) system and a Bluetooth system that share a single antenna, said method comprising the steps of:

monitoring activity of said WLAN system and said Bluetooth system within said device;

determining access priority of said WLAN system and said Bluetooth system;

predicting high priority (HP) patterns of said Bluetooth system;

allocating bandwidth of said device in accordance with said predictions; and

switching said single antenna between said WLAN system and said Bluetooth system in accordance with said bandwidth allocation.

11. The method according to claim 10, wherein said step of allocating bandwidth comprises scheduling WLAN system transmissions to free time periods between Bluetooth high priority frames.

12. The method according to claim 10, wherein said WLAN system is caused to enter Power Save (PS) mode.

13. The method according to claim 10, wherein Access Points (AP) in communication with said device are caused to enter Power Save (PS) mode.

14. The method according to claim 10, further comprising the step of turn off said Bluetooth system in the middle of a transaction.

15. A method of predicting Bluetooth high priority transmissions in a communications device incorporating a wireless local area network (WLAN) system and a Bluetooth system that share a single antenna, said method comprising the steps of:

tracing periodic Bluetooth high priority transmissions by detecting differences between Bluetooth high priority transmission durations; and

entering a Bluetooth high priority protection mode if the results of said tracing meet a predetermined period criteria.

16. The method according to claim 15, further comprising the step of identifying a termination of periodic Bluetooth high priority transmissions.

17. The method according to claim 15, further comprising the step of synchronizing said WLAN system to a Bluetooth frame clock.

18. A coexistence communications device, comprising:

a wireless local area network (WLAN) system;

a Bluetooth system adapted to share a single antenna with said WLAN system; and

a packet traffic arbitration machine operative to receive requests from said Bluetooth system and said WLAN system and to allocate bandwidth therebetween.

19. The device according to claim 18, wherein said packet traffic arbitration machine comprises a Bluetooth prediction machine operative to trace periodic Bluetooth high priority transmissions by detecting differences between Bluetooth high priority transmission durations.

20. The device according to claim 18, wherein said packet traffic arbitration machine comprises a Bluetooth prediction machine operative to trace periodic Bluetooth high priority transmissions by detecting differences between Bluetooth high priority transmission durations and to enter a Bluetooth high priority protection mode if the results of said tracing meet a predetermined period criteria.

21. The device according to claim 20, wherein said Bluetooth prediction machine comprises means for identifying the termination of periodic Bluetooth high priority transmissions.

22. The device according to claim 18, wherein said packet traffic arbitration machine is operative to allocate bandwidth between said Bluetooth system and said WLAN system in accordance with the respective states and priorities of said Bluetooth system and said WLAN system.

23. A coexistence communications device, comprising:

a wireless local area network (WLAN) system;

a Bluetooth system adapted to share a single antenna with said WLAN system;

a Bluetooth prediction machine for detecting Bluetooth high priority transmission periods; and

a decision generator for receiving requests from said Bluetooth system and said WLAN system and to allocate bandwidth therebetween in accordance with the output of said Bluetooth prediction machine.

24. The device according to claim 23, wherein said Bluetooth prediction machine comprises means for predicting high priority patterns of Bluetooth transmissions by detecting differences between Bluetooth high priority transmission durations.

25. The device according to claim 23, wherein said decision generator comprises means for immediately switching said Bluetooth system to said antenna in response to receipt of a Bluetooth high priority transmission request.