Detecting legacy spoofing in reduced functionality user terminals

• US 20060126545A1
• Filed: 10/04/2005
• Published: 06/15/2006
• Est. Priority Date: 10/05/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Nanda, Sanjiv
• Granted Patent: US 7,590,078 B2
• Time in Patent Office: Days
• US Class Current: 370/310
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 52/0209 in terminal devices terminal devices per se H04W88/02
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Backward compatibility may require the use of fields or other indicators that are interpreted by new nodes or stations in a system in a manner different from the way legacy nodes interpret those same fields. In some circumstances, these indicators may be used to “spoof” legacy nodes to behave in certain ways, to allow a next generation protocol to be performed without interference from those legacy nodes. While this practice is may increase communication effectiveness, spoofing may lead to inefficient operation of legacy nodes. Legacy nodes may detect spoofing, including detecting field settings in a legacy portion of a transmitted message, or detecting phase shifts in a message. Once spoofing is detected, a variety of steps may be taken, including determining the duration of the next generation message, entering a low power state for the duration, communicating on alternate channels for the duration, modifying legacy backoff procedures, and others.

Claims

1. An apparatus comprising:

a receiver configured to receive a message, a first part of the message transmitted in a first communication format, the message comprising an alternate format indicator when a second communication format is used to transmit a second part of the message; and

a processor configured to detect the alternate format indicator, determine a duration for transmission of the second part of the message when the alternate format indicator is detected, and direct the receiver to enter a low power state for the determined duration when the alternate format indicator is detected.

2. The apparatus of claim 1, wherein the alternate format indicator comprises a phase shift to part of the message.

3. The apparatus of claim 1, wherein the alternate format indicator is a field set in the message.

4. The apparatus of claim 1, further comprising a decoder configured to decode one or more fields in the message, wherein the processor determines the duration for remaining in the low power state in response to the one or more decoded fields.

5. An apparatus comprising:

a receiver configured to receive a message, a first part of the message transmitted in a first communication format, the message comprising an alternate format indicator when a second communication format is used to transmit a second part of the message; and

means for detecting the alternate format indicator.

6. The apparatus of claim 5, further comprising means for determining a duration of the message.

7. The apparatus of claim 5, further comprising means for reducing power upon detection of the alternate format indicator.

8. The apparatus of claim 5, further comprising means for communicating on an alternate communication channel upon detection of the alternate format indicator.

9. The apparatus of claim 5, wherein the means for detecting the alternate format indicator comprises a means for detecting a phase shift in the received message.

10. The apparatus of claim 5, wherein the means for detecting the alternate format indicator comprises a means for detecting an alternate format indicator field setting in the message.

11. A method comprising:

receiving a message, a first part of the message transmitted in a first communication format, the message comprising an alternate format indicator when a second communication format is used to transmit a second part of the message;

detecting the alternate format indicator;

determining a duration for transmission of the second part of the message when the alternate format indicator is detected; and

entering a low power state for the determined duration when the alternate format indicator is detected.

12. The method of claim 11, wherein the alternate format indicator is transmission of part of the message with a phase shift.

13. The method of claim 11, wherein the alternate format indicator is a field set in the message.

14. The method of claim 11, further comprising:

decoding one or more fields in the message; and

determining a duration for the remaining in the low power state in response to the one or more decoded fields.

15. The method of claim 11, wherein:

the message comprises one or more legacy fields and one or more extension fields; and

the duration is determined from the one or more extension fields.

16. The method of claim 15, wherein the values set for one or more of the legacy fields are different than the values set for one or more corresponding extension fields.

17. The method of claim 14, wherein a first part of the message is transmitted in a first communication format, and a second part of the message is transmitted in a second communication format, the one or more fields for decoding transmitted in the second communication format in the second part of the message.

18. The method of claim 11, wherein entering a low power state comprises disabling decoding of a channel.

19. The method of claim 11, wherein entering a low power state comprises disabling receiving of a channel.

20. The method of claim 11, wherein entering a low power state comprises monitoring an alternate communication channel, the alternate communication channel different from the communication channel on which the message was received.

21. The method of claim 11, wherein entering a low power state comprises modifying a backoff procedure for use after leaving the low power state.

22. A method comprising:

receiving a message, the message comprising a first part transmitted at a first phase and a second part transmitted at a second phase, the second phase different than the first phase;

detecting a phase difference between the first part and the second part; and

entering a low power state when the phase difference is detected.

23. The method of claim 22, further comprising:

decoding one or more fields in the message; and

determining a duration for the remaining in the low power state in response to the one or more decoded fields.

24. The method of claim 23, wherein:

the message comprises one or more legacy fields and one or more extension fields; and

wherein the duration is determined from the one or more extension fields.

25. The method of claim 24, wherein the values set for one or more of the legacy fields are different than the values set for one or more corresponding extension fields.

26. The method of claim 23, wherein a first part of the message is transmitted in a first communication format, and a second part of the message is transmitted in a second communication format, the one or more fields for decoding transmitted in the second communication format in the second part of the message.

27. A method comprising:

receiving a message, a first part of the message transmitted in a first communication format, the message comprising one or more fields for setting parameters of the first communication format;

decoding the one or more fields; and

entering a low power state when a decoded field is set to a value unsupported by the first communication format.

28. The method of claim 27, wherein the one or more fields comprises a reserved bit.

29. The method of claim 27, wherein the one or more fields comprises a rate field.

30. The method of claim 27, wherein the one or more fields comprises a length field.

31. The method of claim 27, further comprising determining a duration for the remaining in the low power state in response to the one or more decoded fields.

32. The method of claim 31, wherein:

the message comprises one or more legacy fields and one or more extension fields; and

the duration is determined from the one or more extension fields.

33. The method of claim 32, wherein the values set for one or more of the legacy fields are different than the values set for one or more corresponding extension fields.

34. The method of claim 27, wherein a second part of the message is transmitted in a second communication format, and one or more of the one or more fields for decoding are transmitted in the second communication format in the second part of the message.