PHYSICAL AND MAC ADAPTATION FOR INTERFERENCE MITIGATION WITH COGNITIVE RADIO

• US 20090124205A1
• Filed: 11/13/2007
• Published: 05/14/2009
• Est. Priority Date: 11/13/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Tan, Kun, Bahl, Paramvir, Padhye, Jitendra D., Radunovic, Bozidar, Ramjee, Ramachandran, Temudo de Castro, Miguel Oom, Narlanka, Gopala S., Aboba, Bernard D.
• Granted Patent: US 8,301,081 B2
• Time in Patent Office: Days
• US Class Current: 455/63.100
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 17/382 for resource allocation, admission control or handover

Abstract

A communication device cognitively monitors interference signals across a communication band so that adaptations for physical and medium access control (MAC) of data packet transmissions are appropriate for a particular interference signal. Characteristics of an interference signal of interest (e.g., bandwidth, power and/or duration relative to an average data packet transmitted over a communication channel of the communication device) are sensed for an appropriate adaptation (e.g., forward error correction, modulation technique, back off, request to send/clear to send protocol, etc.). Patterns for known types of interference sources can be compared so that when recognized an associated adaptation can be used.

Claims

1. A wireless device, comprising:

a transmitter for digital wireless transmission on one of a plurality of communication channels of a communication band;

a cognitive radio sensor for monitoring radio frequencies across the communication band;

an interference module for characterizing an interference signal sensed by the cognitive radio sensor; and

a communication module for physical layer and medium access control (MAC) layer control of the transmitter having an adaptation selected based on the characterization of the interference signal.

2. The wireless device of claim 1, further comprising a stored data structure containing a pattern of a type of interference associated with an adaptation, the pattern utilized by the interference module.

3. The wireless device of claim 2, wherein the pattern of a type of interference further comprises a selected modulation pattern from a group consisting of a television signal, a wireless access point, a wireless personal area networks device, a radio microphone, and a wireless terminal.

4. The wireless device of claim 2, wherein the pattern comprises a pilot signal, a lobe bandwidth size and time-sequence of signal.

5. The wireless device of claim 2, wherein characteristics of the interference signal are stored for persistent adaptation.

6. The wireless device of claim 5, further comprising a location module for determining a location pertaining to the interference signal for persistent adaptation.

7. The wireless device of claim 1, wherein the interference module characterizes an interference signal as narrowband relative to a channel bandwidth utilized by the transmitter and selects increased forward error correction adaptation by the communication module in response.

8. The wireless device of claim 7, wherein the interference module further characterizes the interference signal as a wideband interference signal relative to channel bandwidth and as low power relative to a physical layer power setting of the transmitter and selects an adaptation in response.

9. The wireless device of claim 8, wherein the adaptation is selected from a group consisting of trading away data rate for a more robust modulation scheme, trading away data rate for a more robust forward error correction coding scheme, and increasing transmit power.

10. The wireless device of claim 7, wherein the interference module further characterizes a duration of an interference signal relative to a data transmission segment, and selects a change of channel adaptation in response to a determination of a long term interference signal.

11. The wireless device of claim 10, wherein characterizing a duration as short term or long term depends upon a threshold defined as ten times an amount of time necessary to send an average data packet.

12. The wireless device of claim 10, wherein in response to a determination of a short-term interference signal and a further determination of an IEEE 802.11 hidden terminal creating the interference signal, the communication module enables request to send and clear to send (RTS/CTS) protocol.

13. The wireless device of claim 10, wherein in response to a determination of a short-term interference signal, the communication module selects a back off adaptation.

16. The wireless device of claim 1, further comprising:

storing a pattern of a type of interference associated with an adaptation; and

comparing the characterization of the interference signal to the pattern to recognize the interference signal; and

selecting the associated communication adaptation.

14. The wireless device of 1, wherein the communication module characterizes an interference signal of interest to ascertain power, duration and bandwidth size.

15. A method of mitigating interference, comprising:

transmitting on a wireless digital packet communication channel of a plurality of channels of a communication band,

monitoring power and duration of radio frequencies across the communication band;

characterizing an interference signal; and

selecting a communication adaptation for physical layer and medium access control (MAC) layer control based on the interference characterization.

17. The method of claim 15, further comprising selecting increased forward error correction adaptation in response to a narrowband characterization of the interference signal.

18. The method of claim 17, further comprising selecting a more robust modulation or forward error coding adaptation in response to a wideband, low power characterization of the interference signal.

19. The method of claim 18, further comprising selecting an avoidance adaptation in response to a long duration, high power, wideband characterization of the interference signal.

20. The method of claim 19, further comprising selecting enablement of request to send, clear to send (RTS/CTS) protocol adaptation in response to a wideband, high power, short duration characterization of the interference signal.

21. The method of claim 19, further comprising selecting a back off adaption in response to a wideband, highpower, short duration and hidden terminal characterization of the interference signal.

22. A computer-implemented system, comprising:

means for transmitting on a wireless digital packet communication channel of a plurality of channels of a communication band,

means for monitoring power and duration of radio frequencies across the communication band;

means for characterizing an interference signal; and

means for selecting a communication adaptation for physical layer and medium access control (MAC) layer control based on the interference characterization.