Quasi Co-Location For Beamforming

• US 20180331860A1
• Filed: 09/27/2017
• Published: 11/15/2018
• Est. Priority Date: 09/30/2016
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bergman, Svante, Frenne, Metties, Jongren, George, Sorrentino, Stefano
• Granted Patent: US 10,547,364 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path

Abstract

A method implemented in a user equipment (UE) includes receiving a first reference signal (RS) from a first transmit antenna port and performing channel estimation based on the first RS. The method also includes obtaining an indication that the first RS and a second RS share a spatial property and receiving the second RS from a second transmit antenna port. The method further includes inferring the shared spatial property for the second RS based on the indication and performing channel estimation based on the second RS using the inferred spatial property.

Claims

1. A method implemented in a user equipment (UE) (110), comprising:

receiving a first reference signal (RS) from a first transmit antenna port;

performing channel estimation based on the first RS;

obtaining an indication that the first RS and a second RS share a spatial property;

receiving the second RS from a second transmit antenna port;

inferring the shared spatial property for the second RS based on the indication; and

performing channel estimation based on the second RS using the inferred spatial property.

2. The method of claim 1, wherein the channel estimation based on the second RS includes duplicating a partial result of the channel estimation on the first RS.

3. The method of any of claims 1, wherein the channel estimation based on the second RS includes omitting a processing or measurement activity performed on the first RS.

4. The method of claim 1, wherein the channel estimations based on the first and second RSs are performed jointly.

5. The method of claim 1, wherein:

the channel estimation based on the first RS comprises determining a value of a parameter representing a spatial property of a receiver; and

the second RS is received while reusing the value.

6. The method of claim 1, wherein:

the channel estimation based on the first RS comprises generating an estimation filter based on the shared at least one spatial property; and

the channel estimation based on the second RS comprises applying the generated estimation filter.

7. The method of claim 1, wherein the indication is a co-location indication or a quasi-co-location indication.

8. The method of claim 1, wherein the indication is carried in a messaged received from a network node.

9. The method of claim 1, wherein the indication is pre-agreed.

10. The method of claim 1, wherein the at least one spatial property is selected from:

a channel correlation parameter;

a spatial correlation matrix of the channel;

a receiver-side spatial correlation matrix of the channel;

a factor of a spatial correlation matrix;

a matrix factor of a spatial correlation matrix;

a linear combination elements of a spatial correlation matrix;

a non-scalar property;

a metric representing a receive beam weight configuration; and

a subset or a linear combination of the spatial channel correlation.

11. The method of claim 1, wherein performing channel estimation based on the first RS comprises estimating a channel correlation matrix based on the first RS.

12. The method of claim 1, further comprising obtaining a processing gain when performing channel estimation based on the second RS.

13. The method of claim 1, wherein the first RS is a synchronization signal or a signal to be used for CSI determination and the second RS is a signal to be used for CSI determination.

14. The method of claim 1, wherein a relation between a transmission of the first RS and a transmission of the second RS is implicitly dependent on a point in time when the first and second RSs are transmitted.

16. The UE of claim 14, wherein the receiver is a multi-antenna receiver.

18. The UE of claim 14, wherein the channel estimation based on the second RS includes duplicating a partial result of the channel estimation on the first RS.

19. The UE of claim 14, wherein the channel estimation based on the second RS includes omitting a processing or measurement activity performed on the first RS.

20. The UE of claim 14, wherein the channel estimations based on the first and second RSs are performed jointly.

21. The UE of claim 14, wherein:

the channel estimation based on the first RS comprises determining a value of a parameter representing a spatial property of a receiver; and

the second RS is received while reusing the value.

22. The UE of claim 14, wherein:

the channel estimation based on the first RS comprises generating an estimation filter based on the shared at least one spatial property; and

the channel estimation based on the second RS comprises applying the generated estimation filter.

23. The UE of claim 14, wherein the indication is a co-location indication or a quasi-co-location indication.

24. The UE of claim 14, wherein the indication is carried in a messaged received from a network node.

25. The UE of claim 14, wherein the indication is pre-agreed.

26. The UE of claim 14, wherein the at least one spatial property is selected from:

a channel correlation parameter;

a spatial correlation matrix of the channel;

a receiver-side spatial correlation matrix of the channel;

a factor of a spatial correlation matrix;

a matrix factor of a spatial correlation matrix;

a linear combination elements of a spatial correlation matrix;

a non-scalar property;

a metric representing a receive beam weight configuration; and

a subset or a linear combination of the spatial channel correlation.

15. A user equipment (UE) comprising:

a receiver;

a transmitter;

a processor; and

a memory storing instructions executable by the processor to;

receive, using the receiver, a first reference signals (RS) from at least one transmit antenna port;

perform channel estimation based on the first RS;

obtain an indication that the first RS and a second RS share a spatial property;

receive, using the receiver, the second RS from a second transmit antenna port;

infer the shared spatial property for the second RS; and

perform channel estimation based on the second RS using the inferred spatial property.

17. The UE of claim 15, wherein the receiver is equipped with more than one antenna element which is controllable in an analog domain, a digital domain, or both.

27. The UE of claim 15, wherein the first RS is a synchronization signal or a signal to be used for CSI determination and the second RS is a signal to be used for CSI determination.

28. The UE of claim 15, wherein a relation between a transmission of the first RS and a transmission of the second RS is implicitly dependent on a point in time when the first and second RSs are transmitted.