Carrier sense adaptive transmission (CSAT) in unlicensed spectrum

• US 9,491,632 B2
• Filed: 09/15/2014
• Issued: 11/08/2016
• Est. Priority Date: 09/24/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sadek, Ahmed Kamel
• Primary Examiner(s): Elliott, IV, Benjamin H
• Application Number:
  US14/486,855
• Publication Number:
  US 20150085841A1
• Time in Patent Office: 785 Days
• US Class Current: 1/1
• CPC Class Codes: H04J 3/00 Time-division multiplex systems H04J14/00 takes precedence; relay systems H04B7/14; selecting techniques H04Q
• CPC Class Codes: H04J 3/16 in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted H04J3/17, H04J3/24 take precedence
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0098 Signalling of the activation or deactivation of component carriers, subcarriers or frequency bands
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/1215 for collaboration of different radio technologies
• 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 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]

Abstract

Systems and methods for Carrier Sense Adaptive Transmission (CSAT) and related operations in unlicensed spectrum are disclosed to reduce interference between co-existing Radio Access Technologies (RATs). The parameters for a given CSAT communication scheme may be adapted dynamically based on received signals from a transceiver for a native RAT to be protected and an identification of how that RAT is utilizing a shared resource such as an unlicensed band. Other operations such as Discontinuous Reception (DRX) may be aligned with a CSAT Time Division Multiplexed (TDM) communication pattern by way of a DRX broadcast/multicast message. Different TDM communication patterns may be staggered in time across different frequencies. Channel selection for a co-existing RAT may also be configured to afford further protection to native RATs by preferring operation on secondary channels as opposed to primary channels.

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

setting one or more cycling parameters of a first Time Division Multiplexing (TDM) communication pattern defining activated and deactivated periods of transmission on a first frequency for a second RAT sharing the resource, wherein the setting is based on the identified utilization of the resource;

setting one or more cycling parameters of a second TDM communication pattern defining activated and deactivated periods of transmission on a second frequency for the second RAT, wherein the setting is based on the identified utilization of the resource, and wherein the first TDM communication pattern and the second TDM communication pattern are staggered in time with respect to an overlap in their activated and deactivated periods; and

cycling operation of the second RAT between activated and deactivated periods of transmission over the resource on the first and second frequencies in accordance with the first and second TDM communication patterns.

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

3. The method of claim 1, wherein:

the first RAT comprises Wi-Fi technology; and

the second RAT comprises Long Term Evolution (LTE) technology.

4. The method of claim 1, wherein:

the activated periods of the first TDM communication pattern correspond to the deactivated periods of the second TDM communication pattern; and

the deactivated periods of the first TDM communication pattern correspond to the activated periods of the second TDM communication pattern.

5. The method of claim 1, further comprising:

transmitting data traffic for a corresponding application on the first frequency during an activated period of the first TDM communication pattern; and

transmitting the data traffic on the second frequency during a deactivated period of the first TDM communication pattern.

6. The method of claim 5, further comprising transmitting the data traffic on the first frequency during a deactivated period of the second TDM communication pattern.

7. The method of claim 5, further comprising scheduling the data traffic for transmission over the first and second frequencies based on a Quality of Service (QoS) requirement associated with the corresponding application.

8. 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 the first transceiver operates in accordance with a first RAT to receive the signals;

a processor configured to;

identify a utilization of the resource that is associated with the first RAT, wherein the identification is based on the received signals,

set one or more cycling parameters of a first Time Division Multiplexing (TDM) communication pattern defining activated and deactivated periods of transmission on a first frequency for a second RAT sharing the resource, wherein the setting is based on the identified utilization of the resource,

set one or more cycling parameters of a second TDM communication pattern defining activated and deactivated periods of transmission on a second frequency for the second RAT, wherein the setting is based on the identified utilization of the resource, and wherein the first TDM communication pattern and the second TDM communication pattern are staggered in time with respect to an overlap in their activated and deactivated periods, and

control cycling of operation of the second RAT between activated and deactivated periods of transmission over the resource on the first and second frequencies in accordance with the first and second TDM communication patterns; and

memory coupled to the processor for storing related data and instructions.

9. The apparatus of claim 8, wherein the resource is an unlicensed radio frequency band.

10. The apparatus of claim 8, wherein:

the first RAT comprises Wi-Fi technology; and

the second RAT comprises Long Term Evolution (LTE) technology.

11. The apparatus of claim 8, wherein:

the activated periods of the first TDM communication pattern correspond to the deactivated periods of the second TDM communication pattern; and

the deactivated periods of the first TDM communication pattern correspond to the activated periods of the second TDM communication pattern.

12. The apparatus of claim 8, further comprising a second transceiver operating in accordance with the second RAT and configured to:

transmit data traffic for a corresponding application on the first frequency during an activated period of the first TDM communication pattern; and

transmit the data traffic on the second frequency during a deactivated period of the first TDM communication pattern.

13. The apparatus of claim 12, wherein the second transceiver is further configured to transmit the data traffic on the first frequency during a deactivated period of the second TDM communication pattern.

14. The apparatus of claim 12, wherein the processor is further configured to schedule the data traffic for transmission over the first and second frequencies based on a Quality of Service (QoS) requirement associated with the corresponding application.

15. A method of channel selection among a plurality of frequencies 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 a utilization of the resource that is associated with the first RAT, wherein the identification is based on the received signals;

selecting a first frequency from the plurality of frequencies for communication over the resource by a second RAT in response to the identified utilization of the resource being below a clean channel threshold on the first frequency; and

selecting a second frequency from the plurality of frequencies for communication over the resource by the second RAT in response to the identified utilization of the resource being above the clean channel threshold on each of the plurality of frequencies,

wherein a frequency associated with a secondary channel of the first RAT is selected as the second frequency if one or more secondary channels are identified as operating on the resource, and

wherein a frequency associated with a primary channel of the first RAT is selected as the second frequency if no secondary channels are identified as operating on the resource.

16. The method of claim 15, further comprising setting a Time Division Multiplexing (TDM) communication pattern defining activated and deactivated periods of transmission on the second frequency over the resource by the second RAT, wherein the setting is based on the identified utilization of the resource.

17. The method of claim 16, wherein, in response to the frequency associated with the primary channel of the first RAT being selected as the second frequency, the TDM communication pattern is set to use activated and deactivated period durations below a threshold to reduce interference to connection setup signaling of the first RAT on the primary channel.

18. The method of claim 16, wherein, in response to the frequency associated with the primary channel of the first RAT being selected as the second frequency, the TDM communication pattern is set to minimize overlap of the activated periods with beacon signaling of the first RAT on the primary channel.

19. The method of claim 15, further comprising:

sending a transmission on the second frequency at a first power level in response to the frequency associated with the primary channel of the first RAT being selected as the second frequency; and

sending a transmission on the second frequency at a second power level in response to the frequency associated with the secondary channel of the first RAT being selected as the second frequency,

wherein the first power level is lower than the second power level.

20. The method of claim 15, further comprising:

decoding a beacon signal among the received signals; and

identifying if the one or more secondary channels are operating on the resource based on the decoding.

21. The method of claim 15, wherein the resource is an unlicensed radio frequency band.

22. The method of claim 15, wherein:

the first RAT comprises Wi-Fi technology; and

the second RAT comprises Long Term Evolution (LTE) technology.

23. An apparatus for channel selection among a plurality of frequencies for reducing interference between Radio Access Technologies (RATs), comprising:

a first transceiver configured to receive signals via a resource, wherein the first transceiver operates in accordance with a first RAT to receive the signals;

a processor configured to;

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

select a first frequency from the plurality of frequencies for communication over the resource by a second RAT in response to the identified utilization of the resource being below a clean channel threshold on the first frequency; and

select a second frequency from the plurality of frequencies for communication over the resource by the second RAT in response to the identified utilization of the resource being above the clean channel threshold on each of the plurality of frequencies,

wherein a frequency associated with a secondary channel of the first RAT is selected as the second frequency if one or more secondary channels are identified as operating on the resource, and

wherein a frequency associated with a primary channel of the first RAT is selected as the second frequency if no secondary channels are identified as operating on the resource; and

memory coupled to the processor for storing related data and instructions.

24. The apparatus of claim 23, wherein the processor is further configured to set a Time Division Multiplexing (TDM) communication pattern defining activated and deactivated periods of transmission on the second frequency over the resource by the second RAT, wherein the setting is based on the identified utilization of the resource.

25. The apparatus of claim 24, wherein, in response to the frequency associated with the primary channel of the first RAT being selected as the second frequency, the TDM communication pattern is set to use activated and deactivated period durations below a threshold to reduce interference to connection setup signaling of the first RAT on the primary channel.

26. The apparatus of claim 24, wherein, in response to the frequency associated with the primary channel of the first RAT being selected as the second frequency, the TDM communication pattern is set to minimize overlap of the activated periods with beacon signaling of the first RAT on the primary channel.

27. The apparatus of claim 23, further comprising a second transceiver operating in accordance with the second RAT and configured to:

send a transmission on the second frequency at a first power level in response to the frequency associated with the primary channel of the first RAT being selected as the second frequency; and

send a transmission on the second frequency at a second power level in response to the frequency associated with the secondary channel of the first RAT being selected as the second frequency,

wherein the first power level is lower than the second power level.

28. The apparatus of claim 23, wherein the processor is further configured to:

decode a beacon signal among the received signals; and

identify if the one or more secondary channels are operating on the resource based on the decoding.

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

30. The apparatus of claim 23, wherein:

the first RAT comprises Wi-Fi technology; and

the second RAT comprises Long Term Evolution (LTE) technology.