Base station coordination for cross-link interference cancelation
Techniques and apparatuses are described for enabling base stations ( 121, 122 ) to coordinate for canceling cross-link interference ( 380 ). The techniques and apparatuses described herein overcome challenges that a single base station ( 121 ) might otherwise face in trying to compensate a reception ( 131 ) by the base station ( 121 ) for cross-link interference ( 382 ) from a transmission ( 132 ) by another base station ( 122 ). The techniques and apparatuses described herein enable the base stations ( 121, 122 ) to form coordination sets to exchange information to enable the base stations ( 121, 122 ) to accurately reconstruct cross-link interference ( 380 ) and ultimately cancel the cross-link interference ( 380 ) to improve link quality.
1. A method performed by a first base station of a base-station coordination set in coordination with a second base station of the base-station coordination set to cancel a cross-link interference, the method comprising:
receiving, by the first base station and from the second base station, information about a future downlink transmission from the second base station to a second user equipment;
based on the information received from the second base station about the future downlink transmission, modeling, by the first base station, the cross-link interference expected at a future time at the first base station from the future downlink transmission;
generating, by the first base station and based on the model, a cancelation filter configuration; and
applying, by the first base station, the cancelation filter configuration to an uplink transmission from a first user equipment that is received at the future time.
2. The method of claim 1 , wherein:
the receiving the information about the future downlink transmission comprises:
receiving I/Q samples for the future downlink transmission;
and
the generating the cancelation filter configuration comprises:
generating a cancelation filter based on the I/Q samples.
3. The method of claim 2 , wherein the applying the cancelation filter configuration comprises:
applying the generated cancelation filter to signals of the uplink transmission.
4. The method of claim 1 , wherein the modeling the cross-link interference comprises:
switching from using a Gaussian interference estimation calculation to a non-Gaussian interference estimation calculation based on the information about the future downlink transmission.
5. The method of claim 1 , wherein:
the receiving the information about the future downlink transmission comprises:
receiving frequency and time scheduling information for air interface resources allocated to the future downlink transmission;
and
the generating the cancelation filter configuration comprises:
generating a cancelation filter based on the frequency and time scheduling information.
6. The method of claim 5 ,
wherein the applying the cancelation filter configuration comprises:
applying the generated cancelation filter to signals of the uplink transmission.
7. The method of claim 1 , wherein the receiving the information about the future downlink transmission comprises:
receiving the information about the future downlink transmission from the second base station using an Xn interface.
8. The method of claim 7 , wherein the receiving the information about the future downlink transmission further comprises:
receiving the information about the future downlink transmission using a wireless link, wherein the wireless link is a millimeter wave link, a sub-millimeter wave link, or a free space optical link.
9. The method of claim 1 , further comprising:
based on the modeling of the cross-link interference, transmitting, by the first base station and to the second base station, a request to change a parameter of the future downlink transmission;
receiving, from the second base station, updated information about the future downlink transmission;
updating the model of cross-link interference expected at the future time at the first base station from the future downlink transmission; and
updating the cancelation filter configuration based on the updated model.
10. The method of claim 1 , wherein:
the receiving the information about the future downlink transmission comprises:
receiving a downlink beamforming configuration for the future downlink transmission;
the generating the cancelation filter configuration comprises:
generating an uplink beamforming configuration for reception of the uplink transmission; and
the applying the cancelation filter configuration comprises:
applying the uplink beamforming configuration to a receiver of the first base station.
11. The method of claim 10 , further comprising:
sending, by the first base station, the uplink beamforming configuration to the second base station, the sending being effective to direct the second base station to change the downlink beamforming configuration.
12. A first base station comprising:
a radio frequency (RF) receiver;
an inter-base station interface; and
a processor and memory system coupled to the RF receiver and comprising instructions that are executable by the processor to configure the first base station to:
receive, from a second base station and using the inter-base station interface, information about a future downlink transmission from the second base station to a second user equipment;
based on the information received from the second base station about the future downlink transmission, model a cross-link interference expected at a future time at the first base station from the future downlink transmission;
generate, based on the model, a cancelation filter configuration; and
apply the cancelation filter configuration to an uplink transmission from a first user equipment that is received at the future time.
13. The first base station of claim 12 , wherein the instructions are further executable to configure the first base station to:
receive the information about the future downlink transmission by receiving I/Q samples for the future downlink transmission;
generate the cancelation filter configuration by generating a cancelation filter based on the I/Q samples; and
apply the cancelation filter configuration by applying the cancelation filter to signals of the uplink transmission.
14. The first base station of claim 12 , wherein the instructions are further executable to configure the first base station to:
model the cross-link interference by switching from using a Gaussian interference estimation calculation to a non-Gaussian interference estimation calculation based on the information about the future downlink transmission.
15. The first base station of claim 12 , wherein the instructions are further executable to configure the first base station to:
receive the information about the future downlink transmission by receiving frequency and time scheduling information for air interface resources allocated to the future downlink transmission;
and
generate the cancelation filter configuration by generating a cancelation filter based on the frequency and time scheduling information.
16. The first base station of claim 12 , wherein the instructions are further executable to configure the first base station to:
receive the information about the future downlink transmission from the second base station by receiving the information about the future downlink transmission over a wireless link, wherein the wireless link is a millimeter wave link, a sub-millimeter wave link, or a free space optical link.
17. The first base station of claim 12 , wherein the instructions are further executable to configure the first base station to:
receive the information about the future downlink transmission from the second base station by receiving the information about the future downlink transmission using an Xn interface.
18. The first base station of claim 12 , wherein the instructions are further executable to configure the first base station to:
based on the model of the cross-link interference, transmit, to the second base station, a request to change a parameter of the future downlink transmission;
receive, from the second base station, updated information about the future downlink transmission;
update the model of cross-link interference expected at the future time at the first base station from the future downlink transmission; and
update the cancelation filter configuration based on the updated model.
19. The first base station of claim 12 , wherein the instructions are further executable to configure the first base station to:
receive the information about the future downlink transmission by receiving a downlink beamforming configuration for the future downlink transmission;
generate the cancelation filter configuration by generating an uplink beamforming configuration for reception of the uplink transmission; and
apply the cancelation filter configuration by applying the uplink beamforming configuration to the receiver.
20. The first base station of claim 19 , wherein the instructions are further executable to configure the first base station to:
send the uplink beamforming configuration to the second base station, the sending of the uplink beamforming configuration being effective to direct the second base station to change the downlink beamforming configuration.