Method and device for performing improved beam tracking in next-generation wireless communication system
The present disclosure relates to a 6G communication system for accomplishing ultra-low delay time and a data transmission rate higher than that of 4G and 5G communication systems. According to embodiments of the present disclosure, a base station can match (or map), to a channel state information-reference signal (CSI-RS), beams having a high probability of being selected as the beam with the best performance at the location of a terminal, and can provide the CSI-RS to the terminal. Therefore, the possibility of the inclusion of the beams with the best performance from among the beams corresponding to the CSI-RS can be increased. Thus, beam tracking with more improved performance can be performed when a beamforming technology is operated in millimeter wave and terahertz bands, or ultrahigh frequency bands or higher.
1 . A method performed by a terminal in a communication system, the method comprising:
transmitting, to a base station, a first message including information of a best beam at an arbitrary location;
receiving, from the base station, a second message including cluster information including at least one cluster identifier and beam patterns corresponding to each of the at least one cluster identifier, wherein the beam patterns are grouped into a respective cluster based on the information of the best beam in accordance with predefined criteria, wherein the beam patterns correspond to location specific beam patterns identified based on the arbitrary location and the information of the best beam, and wherein the predefined criteria is satisfied based on whether a Euclidean distance value between the beam patterns is less than or equal to a first threshold or a cosine similarity value is greater than or equal to a second threshold;
identifying whether a cluster identifier corresponding to a changed location of the terminal differs from a cluster identifier corresponding to a previous location of the terminal, based on the cluster information;
in case that the cluster identifier corresponding to the changed location of the terminal differs from the cluster identifier corresponding to the previous location,
transmitting, to the base station, a channel state information (CSI) report including information on a changed cluster, and
receiving, from the base station, a CSI reference signal (CSI-RS) based on the information on the changed cluster; and
in case that the cluster identifier corresponding to the changed location of the terminal does not differ from the cluster identifier corresponding to the previous location of the terminal, determining not to transmit, to the base station, the CSI report.
2 . The method of claim 1 , wherein the location of the terminal is identified based on a result of measuring reference signal received power (RSRP) of a reference signal, and
wherein the reference signal is transmitted by a new base station.
3 . The method of claim 1 ,
wherein the CSI-RS corresponds to at least one beam identified based on a changed beam pattern corresponding to the information on the changed cluster, and
wherein the CSI-RS is identified based on information on a transmission configuration indicator (TCI) state related to the at least one beam corresponding to the CSI-RS.
4 . A method performed by a base station in a communication system, the method comprising:
receiving, from a terminal, a first message including information of a best beam at an arbitrary location;
identifying location specific beam patterns based on the arbitrary location and information of the best beam;
grouping beam patterns, among the location specific beam patterns, into a respective cluster, based on the information of the best beam in accordance with predefined criteria, wherein the predefined criteria is satisfied based on whether a Euclidean distance value between the beam patterns is less than or equal to a first threshold or a cosine similarity value is greater than or equal to a second threshold;
transmitting, to the terminal, a second message including cluster information including at least one cluster identifier and the beam patterns corresponding to each of the at least one cluster identifier, wherein the beam patterns are grouped into the respective cluster; and
in case that a cluster identifier corresponding to a changed location of the terminal differs from a cluster identifier corresponding to a previous location:
receiving, from the terminal, a channel state information (CSI) report including information on a changed cluster, and
transmitting, to the terminal, a CSI reference signal (CSI-RS) based on the information on the changed cluster,
wherein in case that the cluster identifier corresponding to the changed location of the terminal does not differ from the cluster identifier corresponding to the previous location, the CSI report is not received.
5 . The method of claim 1 ,
wherein a location of the terminal is identified based on a result of measuring reference signal received power (RSRP) of a reference signal, and
wherein the reference signal is transmitted by a new base station.
6 . The method of claim 4 ,
wherein the CSI-RS is identified based on information on a transmission configuration indicator (TCI) state related to the at least one beam corresponding to the CSI-RS.
7 . A terminal of a communication system, the terminal comprising:
a transceiver; and
a controller connected to the transceiver,
wherein the controller is configured to:
transmit, to a base station, a first message including information of a best beam at an arbitrary location;
receive, from the base station, a second message including cluster information including at least one cluster identifier and beam patterns corresponding to each of the at least one cluster identifier, wherein the beam patterns are grouped into a respective cluster based on the information of the best beam in accordance with predefined criteria, wherein the beam patterns correspond to location specific beam patterns identified based on the arbitrary location and the information of the best beam, and wherein the predefined criteria is satisfied based on whether a Euclidean distance value between the beam patterns is less than or equal to a first threshold or a cosine similarity value is greater than or equal to a second threshold;
identify whether a cluster identifier corresponding to a changed location of the terminal differs from a cluster identifier corresponding to a previous location of the terminal, based on the cluster information;
in case that the cluster identifier corresponding to the changed location of the terminal differs from the cluster identifier corresponding to the previous location:
transmit, to the base station, a channel state information (CSI) report including information on a changed cluster, and
receive, from the base station, a CSI reference signal (CSI-RS) based on the information on the changed cluster; and
in case that the cluster identifier corresponding to the changed location of the terminal does not differ from the cluster identifier corresponding to the previous location of the terminal, determining not to transmit, to the base station, the CSI report.
8 . The terminal of claim 7 , wherein the location of the terminal is identified based on a result of measuring reference signal received power (RSRP) of a reference signal, and
wherein the reference signal is transmitted by a new base station.
9 . The terminal of claim 7 ,
wherein the CSI-RS corresponds to at least one beam identified based on a changed beam pattern corresponding to the information on the changed cluster, and
wherein the CSI-RS is identified based on information on a transmission configuration indicator (TCI) state related to the at least one beam corresponding to the CSI-RS.
10 . A base station of a communication system, the base station comprising:
a transceiver; and
a controller connected to the transceiver,
wherein the controller is configured to:
receive, from a terminal, a first message including information of a best beam at an arbitrary location;
identify location specific beam patterns based on the arbitrary location and information of the best beam at the arbitrary location;
group beam patterns, among the location specific beam patterns, into a respective cluster, based on the information of the best beam in accordance with predefined criteria, wherein the predefined criteria is satisfied based on whether a Euclidean distance value between the beam patterns is less than or equal to a first threshold or a cosine similarity value is greater than or equal to a second threshold;
transmit, to the terminal, a second message including cluster information including at least one cluster identifier and the beam patterns corresponding to each of the at least one cluster identifier, wherein the beam patterns are grouped into the respective cluster; and
in case that a cluster identifier corresponding to a changed location of the terminal differs from a cluster identifier corresponding to a previous location:
receive, from the terminal, a channel state information (CSI) report including information on a changed cluster, and
transmit, to the terminal, a CSI reference signal (CSI-RS) based on the information on the changed cluster,
wherein in case that the cluster identifier corresponding to the changed location of the terminal does not differ from the cluster identifier corresponding to the previous location, the CSI report is not received.
11 . The base station of claim 10 ,
wherein a location of the terminal is identified based on a result of measuring reference signal received power (RSRP) of a reference signal,
wherein the reference signal is transmitted by a new base station, and
wherein the CSI-RS is identified based on information on a transmission configuration indicator (TCI) state related to the at least one beam corresponding to the CSI-RS.