CARRIER SENSE ADAPTIVE TRANSMISSION (CSAT) COORDINATION IN UNLICENSED SPECTRUM

• US 20150163801A1
• Filed: 12/10/2014
• Published: 06/11/2015
• Est. Priority Date: 12/11/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: SADEK, Ahmed Kamel
• Granted Patent: US 10,334,588 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04W 48/00 Access restriction access security to prevent unauthorised access H04W12/08; Network selection; Access point selection
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/1215 for collaboration of different radio technologies
• CPC Class Codes: H04W 72/1263 Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 76/15 Setup of multiple wireless link connections

Abstract

Systems and methods for Carrier Sense Adaptive Transmission (CSAT) communication in unlicensed spectrum are disclosed. Interference between Radio Access Technologies (RATs) may be reduced utilizing CSAT by, for example: receiving signals via a resource, wherein a first RAT is used to receive the signals; identifying utilization of the resource associated with the first RAT, wherein the identification is based on the received signals; cycling operation of a second RAT between activated and deactivated periods of transmission over the resource in accordance with a Time Division Multiplexing (TDM) communication pattern, wherein the cycling is based on the identified utilization of the resource; and transmitting an Activation/Deactivation Medium Access Control (MAC) Control Element (CE) to a user device associated with the second RAT to activate or deactivate the user device in accordance with the TDM communication pattern.

Claims

1. A method of Carrier Sense Adaptive Transmission (CSAT) for reducing interference between Radio Access Technologies (RATs), comprising:

receiving signals via a resource, wherein a first RAT is used to receive the signals;

identifying utilization of the resource associated with the first RAT, wherein the identification is based on the received signals;

cycling operation of a second RAT between activated and deactivated periods of transmission over the resource in accordance with a Time Division Multiplexing (TDM) communication pattern, wherein the cycling is based on the identified utilization of the resource; and

transmitting an Activation/Deactivation Medium Access Control (MAC) Control Element (CE) to a user device associated with the second RAT to activate or deactivate the user device in accordance with the TDM communication pattern.

2. The method of claim 1, wherein the Activation/Deactivation MAC CE is transmitted to a plurality of user devices individually at respective times, in an activation order based on respective link quality metrics.

3. The method of claim 2, further comprising setting the activation order to prioritize activation of a user device having a lower link quality metric as compared to a user device having a higher link quality metric.

4. The method of claim 1, further comprising scheduling a plurality of user devices individually at respective times, in a scheduling order based on respective link quality metrics, wherein the scheduling order prioritizes scheduling grants to a user device having a higher link quality metric as compared to a user device having a lower link quality metric.

5. The method of claim 4, wherein the scheduling comprises selecting a Modulation and Coding Scheme (MCS) for each of the user devices based on a last available valid Channel Quality Indicator (CQI) for the user device and a backoff factor.

6. The method of claim 1, further comprising:

monitoring ramp-up times for a plurality of user devices;

classifying each of the plurality of user devices as a fast or a slow ramp-up user device based on the monitored ramp-up times;

transmitting a Radio Resource Control (RRC) connection configuration message to slow ramp-up user devices to add a Secondary Cell (SCell) corresponding to the second RAT to the set of serving cells for the user device for activated periods of the TDM communication pattern; and

transmitting an RRC connection deconfiguration message to the slow ramp-up user devices to remove the SCell from the set of serving cells for the user device for deactivated periods of the adapted duty cycle.

7. The method of claim 6, further comprising scheduling each of the plurality of user devices individually at respective times, in a scheduling order based on the monitored ramp-up times, wherein the scheduling order prioritizes scheduling grants to a user device having a faster ramp-up time as compared to a user device having a slower ramp-up time.

8. The method of claim 1, wherein the Activation/Deactivation MAC CE is transmitted in advance of a corresponding activated period of the TDM communication pattern by an activation margin.

9. The method of claim 1, wherein the Activation/Deactivation MAC CE activates the user device for a corresponding activated period of the TDM communication pattern, the method further comprising:

transmitting a deactivation timer value to the user device to cause the user device to deactivate after expiration of the corresponding activated period.

10. The method of claim 1, further comprising refraining from issuing any scheduling grants to the user device in advance of expiration of a corresponding activated period of the TDM communication pattern by a guard duration.

11. The method of claim 1, wherein the resource is an unlicensed radio frequency band.

12. The method of claim 1, wherein:

the first RAT comprises Wi-Fi technology; and

the second RAT comprises LTE technology.

13. An apparatus for Carrier Sense Adaptive Transmission (CSAT) for reducing interference between Radio Access Technologies (RATs), comprising:

a first transceiver configured to receive signals via a resource, wherein a first RAT is used to receive the signals;

a processor configured to identify utilization of the resource associated with the first RAT, wherein the identification is based on the received signals, and to cycle operation of a second RAT between activated and deactivated periods of transmission over the resource in accordance with a Time Division Multiplexing (TDM) communication pattern, wherein the cycling is based on the identified utilization of the resource; and

a second transceiver configured to transmit an Activation/Deactivation Medium Access Control (MAC) Control Element (CE) to a user device associated with the second RAT to activate or deactivate the user device in accordance with the TDM communication pattern.

14. The apparatus of claim 13, wherein the Activation/Deactivation MAC CE is transmitted to a plurality of user devices individually at respective times, in an activation order based on respective link quality metrics.

15. The apparatus of claim 14, wherein the processor is further configured to set the activation order to prioritize activation of a user device having a lower link quality metric as compared to a user device having a higher link quality metric.

16. The apparatus of claim 13, wherein the processor is further configured to schedule a plurality of user devices individually at respective times, in a scheduling order based on respective link quality metrics, wherein the scheduling order prioritizes scheduling grants to a user device having a higher link quality metric as compared to a user device having a lower link quality metric.

17. The apparatus of claim 16, wherein the processor is configured to schedule the plurality of user devices by further selecting a Modulation and Coding Scheme (MCS) for each of the user devices based on a last available valid Channel Quality Indicator (CQI) for the user device and a backoff factor.

18. The apparatus of claim 13, wherein:

the processor is further configured to monitor ramp-up times for a plurality of user devices, and to classify each of the plurality of user devices as a fast or a slow ramp-up user device based on the monitored ramp-up times; and

the second transceiver is further configured to transmit a Radio Resource Control (RRC) connection configuration message to slow ramp-up user devices to add a Secondary Cell (SCell) corresponding to the second RAT to the set of serving cells for the user device for activated periods of the TDM communication pattern, and to transmit an RRC connection deconfiguration message to the slow ramp-up user devices to remove the SCell from the set of serving cells for the user device for deactivated periods of the adapted duty cycle.

19. The apparatus of claim 18, wherein the processor is further configured to schedule each of the plurality of user devices individually at respective times, in a scheduling order based on the monitored ramp-up times, wherein the scheduling order prioritizes scheduling grants to a user device having a faster ramp-up time as compared to a user device having a slower ramp-up time.

20. The apparatus of claim 13, wherein the Activation/Deactivation MAC CE is transmitted in advance of a corresponding activated period of the TDM communication pattern by an activation margin.

21. The apparatus of claim 13, wherein the Activation/Deactivation MAC CE activates the user device for a corresponding activated period of the TDM communication pattern, the second transceiver being further configured to transmit a deactivation timer value to the user device to cause the user device to deactivate after expiration of the corresponding activated period.

22. The apparatus of claim 13, wherein the processor is configured to refrain from issuing any scheduling grants to the user device in advance of expiration of a corresponding activated period of the TDM communication pattern by a guard duration.

23. The apparatus of claim 13, wherein the resource is an unlicensed radio frequency band.

24. The apparatus of claim 13, wherein:

the first RAT comprises Wi-Fi technology; and

the second RAT comprises LTE technology.

25. An apparatus for Carrier Sense Adaptive Transmission (CSAT) for reducing interference between Radio Access Technologies (RATs), comprising:

means for receiving signals via a resource, wherein a first RAT is used to receive the signals;

means for identifying utilization of the resource associated with the first RAT, wherein the identification is based on the received signals;

means for cycling operation of a second RAT between activated and deactivated periods of transmission over the resource in accordance with a Time Division Multiplexing (TDM) communication pattern, wherein the cycling is based on the identified utilization of the resource; and

means for transmitting an Activation/Deactivation Medium Access Control (MAC) Control Element (CE) to a user device associated with the second RAT to activate or deactivate the user device in accordance with the TDM communication pattern.

26. The apparatus of claim 25, wherein the Activation/Deactivation MAC CE is transmitted to a plurality of user devices individually at respective times, in an activation order based on respective link quality metrics.

27. The apparatus of claim 25, further comprising means for scheduling a plurality of user devices individually at respective times, in a scheduling order based on respective link quality metrics, wherein the scheduling order prioritizes scheduling grants to a user device having a higher link quality metric as compared to a user device having a lower link quality metric.

28. A non-transitory computer-readable medium comprising instructions, which, when executed by a processor, cause the processor to perform operations for Carrier Sense Adaptive Transmission (CSAT) for reducing interference between Radio Access Technologies (RATs), the non-transitory computer-readable medium comprising:

instructions for receiving signals via a resource, wherein a first RAT is used to receive the signals;

instructions for identifying utilization of the resource associated with the first RAT, wherein the identification is based on the received signals;

instructions for cycling operation of a second RAT between activated and deactivated periods of transmission over the resource in accordance with a Time Division Multiplexing (TDM) communication pattern, wherein the cycling is based on the identified utilization of the resource; and

instructions for transmitting an Activation/Deactivation Medium Access Control (MAC) Control Element (CE) to a user device associated with the second RAT to activate or deactivate the user device in accordance with the TDM communication pattern.

29. The non-transitory computer-readable medium of claim 28, wherein the Activation/Deactivation MAC CE is transmitted to a plurality of user devices individually at respective times, in an activation order based on respective link quality metrics.

30. The non-transitory computer-readable medium of claim 28, further comprising instructions for scheduling a plurality of user devices individually at respective times, in a scheduling order based on respective link quality metrics, wherein the scheduling order prioritizes scheduling grants to a user device having a higher link quality metric as compared to a user device having a lower link quality metric.