Method and system for predictive sensing of periodic intermittent interference

• US 8,050,627 B2
• Filed: 12/15/2006
• Issued: 11/01/2011
• Est. Priority Date: 12/15/2006
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Emeott, Stephen P., Makhlouf, Isam R.
• Primary Examiner(s): Ghebretinsae; Temesgh
• Assistant Examiner(s): Tsvey; Gennadiy
• Application Number:
  US11/611,725
• Publication Number:
  US 20080146156A1
• Time in Patent Office: 1,782 Days
• Field of Search: 455/67.15, 455/63, 455/63.1, 455/67.13, 455/67.11, 455/501, 455/505, 455/506, 714/704, 375/224, 370/337, 370/319, 370/333, 370/311, 370/252, 370/347
• US Class Current: 455/63.1
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]

Abstract

A method (10 or 40) or system (200) of predictive sensing of periodic intermittent interference (PII) can include the measuring (12) of energy on a channel for an indication of PII, determining (14) if a channel is currently in a PII on-cycle, and adjusting (16) a clear channel assessment threshold to a new threshold for improved sensitivity of the PII on-cycle. If a current energy level on the channel is below the new threshold and if a previous on-energy characteristic suggests that the current energy level will remain below the new threshold for a predetermined minimum period of time, then a clear channel indication can be provided (20). A busy channel indication is provided (45) when either the current energy level is above the new threshold or the previous on-energy characteristic suggests the current energy level will not remain below the threshold for predetermined minimum period of time.

Claims

1. A method of predictive sensing of periodic intermittent interference (PII), comprising the steps of:

determining if a channel is currently in a PII on-cycle;

adjusting a clear channel assessment threshold to a new threshold for improved sensitivity of the PII on-cycle when the PII on-cycle is determined;

determining if a current energy level on the channel is below the new threshold and if a previous on-energy characteristic suggests that the current energy level will remain below the new threshold for a predetermined minimum period of time; and

providing a clear channel indication if the current energy level is below the new threshold and the previous on-energy characteristic suggests that the current energy level will remain below the new threshold for the predetermined minimum period of time.

2. The method of claim 1, wherein the method further comprises the step of using a standard Clear Channel Assessment (CCA) when the channel is not in the PII on-cycle to provide either a busy channel indication or a clear channel indication.

3. The method of claim 1, wherein the method further comprises the step of measuring energy on a channel for an indication of PII.

4. The method of claim 1, wherein the method further comprises the step of providing a busy channel indication when either the current energy level is above the new threshold or the previous on-energy characteristic suggests the current energy level will not remain below the threshold for predetermined minimum period of time.

5. The method of claim 1, wherein the method further comprises the step of storing recent energy measurements in a buffer.

6. The method of claim 1, wherein the method further comprises the step of detecting PII on the channel and extracting PII timing characteristics when detecting PII on the channel.

7. The method of claim 1, wherein the step of adjusting the clear channel assessment threshold comprises the step of lowering the Clear Channel Assessment (CCA) busy channel threshold to a predetermined threshold.

8. The method of claim 1, wherein the predetermined threshold is −

82 dBm corresponding to valid OFDM frame.

9. The method of claim 1, wherein the step of adjusting the clear channel assessment threshold comprises the step of modifying the Clear Channel Assessment (CCA) busy channel threshold adaptively based on recent channel energy measurement statistics.

10. The method of claim 1, wherein the previous on-energy characteristic is the channel energy measurements during one or more previous on-cycles.

11. A system of predictive sensing of periodic intermittent interference (PII), comprising:

a transceiver; and

a processor coupled to the transceiver, wherein the processor is programmed to;

determine if a channel is currently in a PII on-cycle;

adjust a clear channel assessment threshold to a new threshold for improved sensitivity of the PII on-cycle when the PII on-cycle is determined;

determine if a current energy level on the channel is below the new threshold and if a previous on-energy characteristic suggests that the current energy level will remain below the new threshold for a predetermined minimum period of time; and

provide a clear channel indication if the current energy level is below the new threshold and the previous on-energy characteristic suggests that the current energy level will remain below the new threshold for the predetermined minimum period of time.

12. The system of claim 11, wherein the processor is further programmed to use a standard Clear Channel Assessment (CCA) when the channel is not in the PII on-cycle to provide either a busy channel indication or a clear channel indication.

13. The system of claim 11, wherein the processor is programmed to provide a busy channel indication when either the current energy level is above the new threshold or the previous on-energy characteristic suggests the current energy level will not remain below the threshold for predetermined minimum period of time.

14. The system of claim 11, wherein the processor is programmed to detect PII on the channel and extract PII timing characteristics when detecting PII on the channel.

15. The system of claim 11, wherein the processor is further programmed to adjust the clear channel assessment threshold by lowering the Clear Channel Assessment (CCA) busy channel threshold to a predetermined threshold.

16. The system of claim 11, wherein the processor is further programmed to adjust the clear channel assessment threshold by modifying the Clear Channel Assessment (CCA) busy channel threshold adaptively based on recent channel energy measurement statistics.

17. The system of claim 11, wherein the processor is further programmed to determine if the previous on-energy characteristic suggest that the current energy level will remain below the new threshold for the predetermined minimum period of time by comparing the channel energy measurements during one or more previous on-cycles with the current energy level.

18. The system of claim 11, wherein the system is an access point in a WLAN or WiMAX or WiFi communication system.

19. A system of predictive sensing of periodic intermittent interference (PII), comprising:

a transceiver;

a PII detector coupled to the transceiver; and

a processor coupled to the transceiver and the PII detector, wherein the processor is programmed to;

monitor for PII on a current channel; and

determine if a channel is currently in a PII on-cycle;

adjust a clear channel assessment threshold to a new threshold for improved sensitivity of the PII on-cycle when the PII on-cycle is determined;

determine if a current energy level on the channel is below the new threshold and if a previous on-energy characteristic suggests that the current energy level will remain below the new threshold for a predetermined minimum period of time; and

provide a clear channel indication if the current energy level is below the new threshold and the previous on-energy characteristic suggests that the current energy level will remain below the new threshold for the predetermined minimum period of time.

20. The system of claim 19, wherein the processor is programmed to provide a busy channel indication when either the current energy level is above the new threshold or the previous on-energy characteristic suggests the current energy level will not remain below the threshold for predetermined minimum period of time.