Method and apparatus for synchronizing WLAN in a multi-mode radio system

• US 20060068837A1
• Filed: 02/28/2005
• Published: 03/30/2006
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: Spreadtrum Communications Inc (Tsinghua Holdings Co., Ltd.)
• Original Assignee: Quorum Systems, Inc. (Tsinghua Holdings Co., Ltd.)
• Inventors: Malone, Lawrence Jarrett
• Granted Patent: US 7,333,830 B2
• Time in Patent Office: Days
• US Class Current: 455/552.100
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04M 2250/06 including a wireless LAN interface
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 72/1215 for collaboration of different radio technologies
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area 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

Methods and apparatus for synchronizing Wireless Local Area Network (WLAN) communication within a multi-mode radio. A multi-mode radio can support communication with a WLAN and at least one other wireless communication system. The multiple systems can be distinct and asynchronous. Transmitting, or attempting to transmit, over a WLAN communication link can result in interference that degrades the sensitivity of a receiver in another communication system, or that interferes with a transmission in another communication system. The WLAN transmissions can be synchronized to operation in another communication system by generating a signal that can be coupled to a collision avoidance system in the WLAN transmitter. The signal can operate to cause the WLAN transmitter to reschedule the transmission to another time such that the resources of the multi-mode radio are conserved and the WLAN interference is minimized.

Claims

1. A method of controlling a multi-mode wireless communication device, the method comprising:

generating an energy signal in a first sub-system of the multi-mode wireless communication device, the first sub-system configured to enable the multi-mode wireless communication device to communicate with a first wireless communication system; and

coupling the energy signal to a receive signal path of a Wireless Local Area Network (WLAN) sub-system within the multi-mode wireless communication device to control the multi-mode wireless communication device, the WLAN sub-system implementing collision avoidance.

2. The method of claim 1, wherein generating the energy signal in the first sub-system comprises generating a signal having an amplitude sufficient to exceed a predetermined threshold in the WLAN sub-system.

3. The method of claim 1, wherein generating the energy signal in the first sub-system comprises generating a signal configured to exceed a correlation threshold in the WLAN sub-system.

4. The method of claim 1, wherein generating the energy signal in the first sub-system comprises generating a signal encoded with a Barker sequence used in the WLAN sub-system.

5. The method of claim 4, wherein the signal encoded with the Barker sequence uses a Barker sequence 1, −

1, 1, 1, −

1, 1, 1, 1, −

1, −

1, −

1 occurring substantially within a 1 millisecond time period.

6. The method of claim 1, wherein coupling the energy signal to the receive signal path comprises coupling a baseband energy signal to a receive input of a baseband portion of the WLAN sub-system.

7. The method of claim 1, wherein coupling the energy signal to the receive signal path comprises coupling an RF energy signal to an RF receive signal path of the WLAN sub-system.

8. The method of claim 1, wherein generating the energy signal in the first sub-system comprises:

determining a time that the first sub-system is active;

determining a time that the first sub-system is receiving wireless signals from the first wireless communication system; and

generating the energy signal during the time that the first sub-system is receiving.

9. The method of claim 1, wherein generating the energy signal in the first sub-system comprises:

determining a time that the first sub-system is active;

determining a time that the first sub-system is transmitting wireless signals to the first wireless communication system; and

generating the energy signal during the time that the first sub-system is transmitting.

10. A method of controlling a multi-mode wireless communication device, the method comprising:

determining a time that a first sub-system is active, the first sub-system configured to enable the multi-mode wireless communication device to communicate with a first wireless communication system;

generating an energy signal in a baseband portion of the first sub-system during at least a portion of the time that the first sub-system is active, the energy signal configured to exceed a predetermined Clear Channel Assessment (CCA) threshold; and

coupling the energy signal to a receive signal path of a baseband portion of a Wireless Local Area Network (WLAN) sub-system within the multi-mode wireless communication device to control the multi-mode wireless communication device, the WLAN sub-system implementing collision avoidance based on the CCA threshold.

11. The method of claim 10, further comprising configuring a multi-mode RF portion of the multi-mode wireless communication device for the first wireless communication system during the portion of time that the first sub-system is active and the energy signal is generated.

12. The method of claim 10, wherein the energy signal comprises a baseband signal selected from the group comprising a periodic signal, a random signal, a pseudorandom signal, or a combination thereof.

13. The method of claim 10, wherein the energy signal comprises a baseband signal at least a portion of which is encoded using a Barker sequence used in the WLAN sub-system.

14. The method of claim 10, wherein the first wireless communication system comprises a GSM telephone system.

15. The method of claim 10, wherein the WLAN sub-system is configured to support communications in accordance with an IEEE 802.11 standard.

16. A multi-mode wireless communication apparatus, the apparatus comprising:

a radio portion;

a Wireless Local Area Network (WLAN) baseband portion coupled to the radio portion and configured to determine a transmit channel availability using a Clear Channel Assessment (CCA) mechanism; and

a sub-system baseband portion coupled to the radio portion and configured to support communications over a wireless communication system, the sub-system baseband portion distinct from the WLAN baseband portion, and configured to determine a time that communications with the wireless communication system is active, generate an energy signal during at least a portion of the time that communications with the wireless communication system is active, and couple the energy signal to a receive input of the WLAN baseband portion.

17. The apparatus of claim 16, wherein the radio portion comprises:

a WLAN radio portion coupled to the WLAN baseband portion and configured to communicate with a WLAN communication system; and

a sub-system RF portion coupled to the sub-system baseband portion and configured to communicate with the wireless communication system.

18. The apparatus of claim 16, wherein the radio portion comprises a multimode radio portion configured to support in a time multiplex manner a WLAN communication system and the wireless communication system.

19. The apparatus of claim 16, further comprising a signal combiner having a first input coupled to a WLAN receive output of the radio portion, a second input coupled to a energy generator output of the sub-system baseband portion, and an output coupled to the receive input of the WLAN baseband portion.

20. The apparatus of claim 16, wherein the CCA mechanism of the WLAN baseband portion monitors a signal at the receive input of the WLAN baseband portion and determines that a WLAN channel is busy if the signal exceeds a predetermined threshold.

21. The apparatus of claim 20, wherein the predetermined threshold comprises a predetermined signal power.

22. The apparatus of claim 20, wherein the predetermined threshold comprises a predetermined correlation threshold.

23. The apparatus of claim 16, wherein the energy signal generated by the sub-system baseband portion comprises a pseudorandom baseband signal.

24. The apparatus of claim 16, wherein the energy signal generated by the sub-system baseband portion comprises a baseband signal encoded with a Barker sequence used in the WLAN baseband portion.

25. The apparatus of claim 16, wherein the sub-system baseband portion comprises:

a timing module configured to determine a time period in which the multi-mode wireless communication apparatus is configured to transmit or receive signals with the wireless communication system; and

an energy generator coupled to the timing module and configured to generate the energy signal during at least a portion of the time period.

26. A multi-mode wireless communication apparatus, the apparatus comprising:

a radio portion configured to generate an energy signal based on an operating state of the radio portion and output the energy signal at an energy signal output;

a Wireless Local Area Network (WLAN) baseband portion having a receive signal input coupled to the radio portion and energy signal output, and configured to support communications with a WLAN communication system and to determine a transmit channel availability using a Clear Channel Assessment (CCA) mechanism; and

a sub-system baseband portion coupled to the radio portion and configured to support communications with a wireless communication system distinct from the WLAN communication system.

27. The apparatus of claim 26, further comprising a signal combiner having a first input coupled to a receive signal output of the radio portion, a second input coupled to the energy signal output, and an output of the signal combiner coupled to the receive signal input of the WLAN baseband portion.