Frequency offset measurement for improved beam selection
Disclosed is a method comprising receiving, from a base station, in a first time slot, a first plurality of channel state information reference signal resources comprising at least two channel state information reference signal resources; and measuring a first frequency offset value per receive beam on a plurality of receive beams by utilizing two or more resources of the first plurality of channel state information reference signal resources per receive beam.
1 . An apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:
receive, from a base station, in a first time slot, a first plurality of channel state information reference signal resources comprising at least two channel state information reference signal resources; and
measure a first frequency offset value per receive beam on a plurality of receive beams by utilizing two or more resources of the first plurality of channel state information reference signal resources per receive beam.
2 . The apparatus according to claim 1 , wherein the first frequency offset value is measured per pair of beams for multiple pairs of beams, wherein a given pair of beams comprises a receive beam associated with the apparatus and a transmit beam associated with the base station.
3 . The apparatus according to claim 1 , wherein the apparatus is further caused to:
measure a first reference signal received power value per receive beam on the plurality of receive beams by utilizing at least one resource of the first plurality of channel state information reference signal resources per receive beam;
select one or more beams from the plurality of receive beams based at least partly on the first reference signal received power value and the first frequency offset value; and
communicate with the base station by using the selected one or more beams.
4 . The apparatus according to claim 3 , wherein the apparatus is further caused to:
determine, per receive beam of the plurality of receive beams, a first value of a metric indicating a variation in a signal-to-noise ratio per receive beam, wherein the first value of the metric is determined based at least partly on the first reference signal received power value and the first frequency offset value;
wherein the one or more beams are selected from the plurality of receive beams based on the metric.
5 . The apparatus according to claim 4 , wherein the first value of the metric is determined based further on a first weight factor indicating a priority of a reference signal received power, and a second weight factor indicating a priority of a frequency offset; wherein the first weight factor and the second weight factor are based on a velocity of the apparatus.
6 . The apparatus according to claim 1 , wherein the first plurality of channel state information reference signal resources is associated with a first transmit beam of the base station; wherein the apparatus is further caused to:
receive, from the base station, in a second time slot, a second plurality of channel state information reference signal resources associated with a second transmit beam of the base station;
measure a second frequency offset value per receive beam on the plurality of receive beams by utilizing two or more resources of the second plurality of channel state information reference signal resources per receive beam.
7 . The apparatus according to claim 6 , wherein the apparatus is further caused to:
measure a first reference signal received power value per receive beam on the plurality of receive beams by utilizing at least one resource of the first plurality of channel state information reference signal resources per receive beam;
determine, per receive beam of the plurality of receive beams, a first value of a metric indicating a variation in a signal-to-noise ratio per receive beam, wherein the first value of the metric is determined based at least partly on the first reference signal received power value and the first frequency offset value;
measure a second reference signal received power value per receive beam on the plurality of receive beams by utilizing at least one resource of the second plurality of channel state information reference signal resources per beam;
determine, per receive beam of the plurality of receive beams, a second value of the metric based at least partly on the second reference signal received power value and the second frequency offset value;
transmit, to the base station, an indication indicating the first value of the metric and/or the second value of the metric for at least one beam of the plurality of receive beams.
8 . The apparatus according to claim 1 , wherein the apparatus is further caused to:
transmit, to the base station, an indication indicating at least the first frequency offset value of at least one beam of the plurality of receive beams.
9 . The apparatus according to claim 1 , wherein the apparatus is further caused to:
determine a precoder matrix indicator based at least partly on the first frequency offset value of the plurality of receive beams; and
transmit the precoder matrix indicator to the base station.
10 . The apparatus according to claim 1 , wherein the first plurality of channel state information reference signal resources comprises more than two channel state information reference signal resources, and wherein the first frequency offset value for a first beam of the plurality of receive beams is measured by utilizing more than two resources of the first plurality of channel state information reference signal resources for the first beam.
11 . The apparatus according to claim 1 , wherein the apparatus is further caused to:
receive, from the base station, a message indicative of a configuration for a tracking reference signal resource set;
wherein the first plurality of channel state information reference signal resources is associated with the tracking reference signal resource set.
12 . The apparatus according to claim 1 , wherein the apparatus is comprised in a terminal device.
13 . An apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to:
transmit, to a terminal device, in a first time slot and on a first transmit beam, a first plurality of channel state information reference signal resources comprising at least two channel state information reference signal resources;
transmit, to the terminal device, in a second time slot and on a second transmit beam, a second plurality of channel state information reference signal resources comprising at least two channel state information reference signal resources;
receive, from the terminal device, an indication indicating at least a first value associated with the first transmit beam and/or a second value associated with the second transmit beam, wherein the first value and the second value indicate a frequency offset or a variation in a signal-to-noise ratio; and
select a beam based at least partly on the indication received from the terminal device, wherein the beam is selected from a plurality of beams comprising at least the first transmit beam and the second transmit beam.
14 . The apparatus according to claim 13 , wherein the apparatus is further caused to:
transmit, to the terminal device, a message comprising a request for switching to a transmission configuration indicator state associated with the selected beam.
15 . The apparatus according to claim 13 , wherein the apparatus is further caused to:
communicate with the terminal device by using the selected beam.
16 . The apparatus according to claim 13 , wherein the apparatus is comprised in a base station.
17 . The apparatus according to claim 13 , wherein a spacing between the channel state information reference signal resources in the first time slot is less than 4 symbols.
18 . A method comprising:
receiving, at a terminal device from a base station, in a first time slot, a first plurality of channel state information reference signal resources comprising at least two channel state information reference signal resources; and
measuring a first frequency offset value per receive beam on a plurality of receive beams by utilizing two or more resources of the first plurality of channel state information reference signal resources per receive beam.
19 . The method according to claim 18 , wherein the first frequency offset value is measured per pair of beams for multiple pairs of beams, wherein a given pair of beams comprises a receive beam associated with the terminal device and a transmit beam associated with the base station.
20 . The method according to claim 18 , further comprising:
measuring a first reference signal received power value per receive beam on the plurality of receive beams by utilizing at least one resource of the first plurality of channel state information reference signal resources per receive beam;
selecting one or more beams from the plurality of receive beams based at least partly on the first reference signal received power value and the first frequency offset value; and
communicating with the base station by using the selected one or more beams.