Blind detection and reporting of interference in unlicensed spectrum

• US 10,531,473 B2
• Filed: 09/23/2016
• Issued: 01/07/2020
• Est. Priority Date: 09/25/2015
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Yerramalli, Srinivas, Chendamarai Kannan, Arumugam, Lei, Jing, Ramanujam, Sridhar, Wei, Yongbin
• Primary Examiner(s): Crutchfield, Christopher M
• Assistant Examiner(s): Lindenbaum, Alan L
• Application Number:
  US15/274,632
• Publication Number:
  US 20170094672A1
• Time in Patent Office: 1,201 Days
• Field of Search: None
• CPC Class Codes: H04J 11/0023 Interference mitigation or co-ordination direct sequence spread spectrum [DSSS] systems H04B1/7097; frequency hopping H04B1/713; allocation criteria for ingress interference avoidance H04L5/0062; frequency allocation criteria for requirements on out-of-channel emissions H04L5/0066; arrangements for removing intersymbol interference or baseband equalisers H04L25/03006; peak power aspects in multicarrier modulation H04L27/2614; power management H04W52/00; traffic scheduling H04W72/54, H04W72/541
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/0236 radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

The disclosure provides for detecting interference in wireless communications. A wireless devices may receive an interfering signal on a portion of unlicensed spectrum. The wireless device may perform cyclic autocorrelation on the interfering signal to determine one or both of a cyclic prefix length and a symbol period. The wireless device may determine a radio access technology of the interfering signal based on one or both of the cyclic prefix length and the symbol period. In an aspect, the wireless device may further transmit an interference report including information regarding the interfering signal including the cyclic prefix length, symbol period, identified radio access technology, or packet length.

Claims

1. A method of detecting interference in wireless communications, comprising:

receiving, by a receiver of a user equipment (UE) that is connected to a base station, an interfering signal on a portion of unlicensed spectrum from a wireless device to which the UE is not connected;

performing, by a processor of the UE, cyclic autocorrelation on the interfering signal to determine a cyclic prefix length and a symbol period;

determining, by the processor of the UE, a radio access technology (RAT) of the interfering signal by comparing the cyclic prefix length and the symbol period of the interfering signal with corresponding properties of known RATs;

adjusting an energy detection threshold by the UE based on the RAT of the interfering signal to mitigate interference to the wireless device;

detecting an event based on the RAT of the interfering signal as determined by the UE, the event indicating at least one of the RAT causing interference for more than a threshold amount of time, the RAT causing interference after not being reported for a defined period of time, the RAT not being stored in a list of neighboring RATs, or the RAT being a previously identified RAT that has not been detected for the defined period of time; and

transmitting, from the UE to the base station, an interference report in response to the event.

2. The method of claim 1, wherein the interference report includes a received signal strength indicator (RSSI) associated with the interfering signal.

3. The method of claim 2, further comprising switching from a first window adaptation technique to a different second window adaptation technique based on the RSSI associated with the interfering signal and a duration of a transmission opportunity (TXOP) of the interfering signal.

4. The method of claim 1, further comprising adjusting a contention window size for channel access based on the RAT of the interfering signal.

5. The method of claim 4, wherein the contention window size for channel access on a first channel is dependent on detection of the RAT of the interfering signal on a different channel.

6. The method of claim 1, further comprising adjusting a transmission opportunity (TXOP) duration based on a duration of a TXOP of the interfering signal.

7. The method of claim 6, wherein the duration of the TXOP of the interfering signal is detected at the base station or reported by one or more UEs.

8. The method of claim 1, wherein the cyclic autocorrelation is performed without receiving a preamble of a data packet and without decoding the interfering signal.

9. The method of claim 1, wherein the interference report includes the cyclic prefix length and the symbol period.

10. The method of claim 1, wherein the interference report includes channels on which the interfering signal was detected or a duration of a packet on the interfering signal.

11. The method of claim 1, wherein the energy detection threshold is a minimum energy level that causes the UE to change at least one of a transmission channel, a transmission power, a contention window size, a transmission opportunity (TXOP) duration, or a window adaptation technique of the UE, wherein the adjusting comprises reducing the energy detection threshold in response to the RAT of the interfering signal being detected as Wi-Fi.

12. The method of claim 1, wherein the base station and the wireless device communicate in different networks.

13. The method of claim 1, wherein the interference report indicates a transmission direction of the interfering signal.

14. The method of claim 1, wherein the interference report indicates multiple cyclic prefix and symbol period combinations for a channel over a period of time.

15. A user equipment (UE) for detecting interference in wireless communications, comprising:

a transceiver configured to receive an interfering signal on a portion of unlicensed spectrum from a wireless device to which the UE is not connected;

a memory; and

a processor communicatively coupled with the transceiver and the memory, the processor and the memory configured to;

perform cyclic autocorrelation on the interfering signal to determine a cyclic prefix length and a symbol period;

determine a radio access technology (RAT) of the interfering signal based on the cyclic prefix length and the symbol period of the interfering signal with corresponding properties of known RATs;

adjust an energy detection threshold based on the RAT of the interfering signal to mitigate interference to the wireless device;

detect an event based on the RAT of the interfering signal as determined by the UE, the event indicating at least one of the RAT causing interference for more than a threshold amount of time, the RAT causing interference after not being reported for a defined period of time, the RAT not being stored in a list of neighboring RATs, or the RAT being a previously identified RAT that has not been detected for the defined period of time; and

transmit, from the UE to a base station, an interference report in response to the event.

16. The UE of claim 15, wherein the interference report further includes a received signal strength indicator (RSSI) associated with the interfering signal.

17. The UE of claim 16, wherein the processor and the memory are configured to switch from a first window adaptation technique to a different second window adaptation technique based on the RSSI associated with the interfering signal and a duration of a TXOP transmission opportunity (TXOP) of the interfering signal.

18. The UE of claim 15, wherein the processor and the memory are configured to adjust a contention window size for channel access based on the RAT of the interfering signal.

19. The UE of claim 18, wherein the contention window size for channel access on a first channel is dependent on detection of the RAT of the interfering signal on a different channel.

20. The UE of claim 15, wherein the processor and the memory are configured to adjust a transmission opportunity (TXOP) duration based on a duration of a TXOP of the interfering signal.

21. The UE of claim 20, wherein the processor and the memory are configured to detect the duration of the TXOP of the interfering signal.

22. The UE of claim 15, wherein the cyclic autocorrelation is performed without receiving a preamble of a data packet and without decoding the interfering signal.

23. The UE of claim 15, wherein the interference report includes the cyclic prefix length and the symbol period.

24. The UE of claim 15, wherein the interference report includes channels on which the interfering signal was detected or a duration of a packet on the interfering signal.

25. The UE of claim 15, wherein the energy detection threshold is a minimum energy level that causes the UE to change at least one of a transmission channel, a transmission power, a contention window size, a transmission opportunity (TXOP) duration, or a window adaptation technique of the UE, wherein the processor and the memory are configured to reduce the energy detection threshold in response to the RAT of the interfering signal being detected as Wi-Fi.

26. The UE of claim 15, wherein the base station and the wireless device communicate in different networks.

27. A user equipment (UE) for detecting interference in wireless communications, comprising:

means for receiving an interfering signal on a portion of unlicensed spectrum from a wireless device to which the UE is not connected;

means for performing cyclic autocorrelation on the interfering signal to determine a cyclic prefix length and a symbol period;

means for determining a radio access technology (RAT) of the interfering signal by comparing the cyclic prefix length and the symbol period of the interfering signal with corresponding properties of known RATs;

means for adjusting an energy detection threshold based on the RAT of the interfering signal to mitigate interference to the wireless device;

means for detecting an event based on the RAT of the interfering signal as determined by the UE, the event indicating at least one of the RAT causing interference for more than a threshold amount of time, the RAT causing interference after not being reported for a defined period of time, the RAT not being stored in a list of neighboring RATs, or the RAT being a previously identified RAT that has not been detected for the defined period of time; and

means for transmitting, from the UE to a base station, an interference report in response to the event.

28. The UE of claim 27, wherein the cyclic autocorrelation is performed without receiving a preamble of a data packet and without decoding the interfering signal.

29. The UE of claim 27, wherein the interference report includes the cyclic prefix length and the symbol period.

30. A non-transitory computer-readable medium storing computer executable code for detecting interference in wireless communications, comprising code to:

receive, by a receiver of a user equipment (UE) that is connected to a base station, an interfering signal on a portion of unlicensed spectrum from a wireless device to which the UE is not connected;

perform, by a processor of the UE, cyclic autocorrelation on the interfering signal to determine a cyclic prefix length and a symbol period;

determine, by the processor of the UE, a radio access technology (RAT) of the interfering signal by comparing the cyclic prefix length and the symbol period of the interfering signal with corresponding properties of known RATs;

adjust, by the processor of the UE, an energy detection threshold based on the RAT of the interfering signal to mitigate interference to the wireless device;

detect an event based on the RAT of the interfering signal as determined by the UE, the event indicating at least one of the RAT causing interference for more than a threshold amount of time, the RAT causing interference after not being reported for a defined period of time, the RAT not being stored in a list of neighboring RATs, or the RAT being a previously identified RAT that has not been detected for the defined period of time; and

transmit, from the UE to the base station, an interference report in response to the event.