Method in a network node, method in a user equipment, a network node and a user equipment for selecting a beam candidate

Patent metadata

Field	Value
Publication number	US-10014920-B2
Application number	US-201214427255-A
Country	US
Kind code	B2
Filing date	Sep 12, 2012
Priority date	Sep 12, 2012
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A method in a network node for selecting a beam candidate in a wireless communication network, including acquiring information including information indicative of signal qualities for multiple beam candidates; assigning to each of the multiple beam candidates a factor indicating signal interference generated by the corresponding beam candidate and selecting a beam candidate taking into account at least the associated signal quality and the factor assigned to the selected beam candidate.

First claim

The invention claimed is:

1. A method in a network node for selecting a beam candidate in a wireless communication network, comprising:
acquiring information indicative of signal qualities for a plurality of beam candidates, the signal quality relating to a link performance for at least one signal;
assigning to each of the plurality of beam candidates a factor indicating signal interference generated by a corresponding beam candidate, the factor comprising a correction to be applied to the information indicative of signal qualities; and
selecting a beam candidate for downlink transmission to a user equipment, UE, the selected beam candidate being selected taking into account at least said associated signal quality and the factor assigned to the selected beam candidate, the information indicative of signal quality being mapped to a performance metric and the selecting comprising selecting the beam candidate that has a best performance metric score including the correction.

2. The method of claim 1 , further comprising transmitting data to the UE on the selected beam candidate.

3. The method of claim 1 , wherein said acquiring is achieved by measuring at least one reference signal transmitted by the UE in a direction towards the network node in an uplink from which the network node estimates said signal quality.

4. The method of claim 1 , wherein said acquiring comprises receiving from said UE a measurement report comprising signal qualities for the plurality of beam candidates.

5. The method of claim 1 , further comprising transmitting to the UE at least one signal using one of the plurality of beam candidates.

6. The method of claim 5 , wherein transmitting the at least one signal comprises transmitting a reference signal precoded with an associated beam candidate.

7. The method of claim 1 , wherein the acquiring further comprises the network node configuring the UE to transmit information indicative of signal qualities for a plurality of beam candidates on a plurality of pilot signals.

8. The method of claim 1 , wherein the selecting comprises identifying a set of primary beam candidates from the plurality of beam candidates based on corresponding received signal quality and where said selecting further comprises selecting from a set of primary beam candidates, the beam candidate with the factor corresponding to a least generated interference.

9. The method of claim 1 , wherein the beam candidate corresponds to beamforming at least one of in an elevation domain and in an azimuth domain.

10. The method of claim 1 , wherein the factor associated with a beam candidate is one of a downtilt and an additional downtilt in an elevation domain.

11. The method of claim 1 , further comprising the network node informing the UE of the factors corresponding to different interference levels generated by beam candidates.

12. The method of claim 11 , wherein the acquiring further comprises configuring the UE to determine an index identifying a recommended beam candidate among a plurality of beam candidates transmitted by the network node by using signal quality assessments for the transmitted beam candidates and the associated factors; and
the selecting a beam candidate for transmission to the UE is based on said index received from the UE.

13. The method of claim 12 , wherein selecting a beam candidate for transmission comprises selecting a beam candidate associated with a reference signal identified by said received index.

14. The method of claim 12 , wherein the factor indicating signal interference generated by the corresponding beam candidate is a power measurement offset for an associated reference signal.

15. The method of claim 14 , further comprising receiving signal quality information for the reference signal identified by said received index, wherein a separate power measurement offset is configured by the network node for the determining of said signal quality information.

16. The method of claim 1 , wherein the factor is one of:
predetermined and is a function of system parameters comprising at least one of current system load, current time of the day and current day of the week; and
independent of which UE is being scheduled by the network node at a time instance.

17. A method in a user equipment, UE, for selecting a beam candidate in a wireless communication system, comprising:
receiving, from a network node, at least one signal transmitted by the network node using one of a plurality of beam candidates;
determining information indicative of signal quality for the plurality of the beam candidates, the signal quality relating to a link performance for said at least one signal; assigning to each beam candidate, a factor indicating signal interference generated by a corresponding beam candidate, the factor comprising a correction to be applied to the information indicative of signal qualities;
selecting a beam candidate among the plurality of beam candidates, the selected beam candidate being selected taking into account at least said associated signal quality and the factor assigned to the selected beam candidate; and
transmitting, to said network node, information indicative of the selected beam candidate, the information indicative of signal quality being mapped to a performance metric and the selecting comprising selecting the beam candidate that has a best performance metric score including the correction.

18. The method of claim 17 , wherein information indicative of the selected beam candidate comprises channel state information.

19. A network node for selecting a beam in a wireless communication network, the network node comprising:
a transmitter configured to transmit to a user equipment, UE, at least one signal using a plurality of beam candidates; and
a processing unit configured to:
acquire information comprising information indicative of signal quality for the plurality of the beam candidates; the signal quality relating to a link performance for said at least one transmitted signal;
assign to each beam candidate, a factor indicating signal interference generated by a corresponding beam candidate, the factor comprising a correction to be applied to the information indicative of signal qualities; and
select a beam candidate among the plurality of beam candidates, for downlink transmission to the UE, the selected beam candidate being selected taking into account at least said associated signal quality and the factor assigned to the selected beam candidate, the information indicative of signal quality being mapped to a performance metric and the selecting comprising selecting the beam candidate that has a best performance metric score including the correction.

20. The network node of claim 19 , wherein the processing unit further comprises a receiver configured to receive at least one reference signal transmitted by the UE in an uplink in a direction towards the network node; and
the processing unit is further configured to measure on the at least one reference signal transmitted by the UE and to estimate said signal quality from the measurement.

21. The network node of claim 20 , wherein the at least one reference signal comprises a signal precoded with an associated beam candidate.

22. The network node of claim 20 , wherein the information indicative of signal quality comprises a measurement report from said UE comprising signal quality of the at least one reference signal.

23. The network node of claim 19 , wherein the transmitter is c

Assignees

• Hammarwall David
• Wernersson Niklas
• Ericsson Telefon Ab L M

Inventors

• Hammarwall David
• Wernersson Niklas

Classifications

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04B7/024

  Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems · CPC title

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04W24/10

  Scheduling measurement reports {; Arrangements for measurement reports} · CPC title

• H04B7/0617 Primary

  for beam forming · CPC title