# US 11,310,020 B2 · Method for performing channel estimation using DMRS in wireless communication system, and apparatus therefor

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- Number: US 11,310,020 B2
- Document ID: US11310020B2
- Status: Granted
- Kind: B2
- Application number: 16/753,223
- Filed: 2018-10-05
- Published: 2020-10-15
- Granted: 2022-04-19
- Earliest claimed: 2017-10-06
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Hyungtae Kim; Kijun Kim; Sukhyon Yoon
- Web page: https://patentgrep.com/patent/US11310020B2

## CPC

- H04W 56/001: {Synchronization between nodes}
- H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal}
- H04L 5/0062: {Avoidance of ingress interference, e.g. ham radio channels}
- H04L 5/0096: {Indication of changes in allocation}
- H04L 5/10: with dynamo-electric generation of carriers; with mechanical filters or demodulators
- H04L 25/02: Details {; arrangements for supplying electrical power along data transmission lines (systems for transmitting signals via power distribution lines H04B3/54)}
- H04L 25/0226: {sounding signals per se}
- H04L 27/2605: {Symbol extensions, e.g. Zero Tail, Unique Word [UW]}
- H04L 27/261: {Details of reference signals}
- H04L 27/2613: {Structure of the reference signals}
- H04L 27/2646: {using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

The present disclosure provides a method for performing channel estimation using a demodulation reference signal (DMRS) in a wireless communication system. More specifically, the method, which is performed by a base station, comprises: when a collision between a DMRS symbol and a synchronization signal block (SSB) occurs, shifting a resource block (RB) of the DMRS symbol where the collision occurs, and all REs bundled with the RE of the DMRS symbol where the collision occurs; transmitting information on the shifted REs to a terminal; and transmitting the DMRS to the terminal on the shifted REs.

## Claims

### Claim 1

A method for transmitting a Demodulation Reference signal (DMRS) in a wireless communication system, the method performed by a base station and comprising:
transmitting, to a terminal, a configuration for resource block (RB) bundling,
wherein an RB bundling unit comprises a plurality of RBs in the frequency domain,
wherein a first RB included in the RB bundling unit is allocated for a specific signal and a second RB included in the RB bundling unit is allocated for a data channel,
wherein, for the first RB, a DMRS collides with the specific signal at a first symbol in the time domain, the DMRS is shifted to a second symbol based on the collision,
wherein, for the second RB, a symbol location of a DMRS for the data channel, where there is no collision, is shifted based on a location of the second symbol;
transmitting, to the terminal, information on the shifted symbol location of the DMRS for the data channel; and
transmitting, to the terminal, the DMRS for the data channel on the shifted symbol location.

### Claim 2 (depends on 1)

The method of claim 1, wherein the DMRS on the first symbol is shifted until the collision does not occur.

### Claim 3 (depends on 1)

The method of claim 1, wherein the specific signal is a Synchronization Signal Block (SSB).

### Claim 4 (depends on 3)

The method of claim 3, wherein the DMRS on the first symbol is a front-loaded DMRS.

### Claim 5 (depends on 4)

The method of claim 4, wherein for the first RB, (i) an additional DMRS collides with the specific signal at a third symbol in the time domain, and (ii) based on the collision between the additional DMRS and the specific signal, the additional DMRS on the third symbol is dropped.

### Claim 6 (depends on 1)

The method of claim 1, wherein the specific signal is received on a physical downlink control channel (PDCCH).

### Claim 7

A method for receiving a Demodulation Reference signal (DMRS) in a wireless communication system, the method performed by a terminal and comprising:
receiving, from a base station, a configuration for resource block (RB) bundling,
wherein an RB bundling unit comprises a plurality of RBs in the frequency domain,
wherein a first RB included in the RB bundling unit is allocated for a specific signal and a second RB included in the RB bundling unit is allocated for a data channel,
wherein, for the first RB, a DMRS collides with the specific signal at a first symbol in the time domain, the DMRS is shifted to a second symbol based on the collision, and
wherein, for the second RB, a symbol location of a DMRS for the data channel, where there is no collision, is shifted based on a location of the second symbol,
receiving, from the base station, information on the shifted symbol location of the DMRS for the data channel; and
receiving, from the base station, the DMRS for the data channel on the shifted symbol location; and
performing a channel estimation using the received DMRS for the data channel.

### Claim 8 (depends on 7)

The method of claim 7, wherein the specific signal is a Synchronization Signal Block (SSB).

### Claim 9 (depends on 8)

The method of claim 8, wherein the DMRS on the first symbol is a front-loaded DMRS.

### Claim 10 (depends on 9)

The method of claim 9, wherein for the first RB, (i) an additional DMRS collides with the specific signal at a third symbol in the time domain, and (ii) based on the collision between the additional DMRS and the specific signal, the additional DMRS on the third symbol is dropped.

### Claim 11 (depends on 7)

The method of claim 7, wherein the specific signal is received on a physical downlink control channel (PDCCH).

### Claim 12

A base station configured for transmitting a Demodulation Reference signal (DMRS) in a wireless communication system, the base station comprising:
a radio frequency (RF) transceiver transmitting and receiving a radio signal; and
a processor functionally connected with the RF transceiver,
wherein the processor is configured to:
transmit, to a terminal, a configuration for resource block (RB) bundling,
wherein an RB bundling unit comprises a plurality of RBs in the frequency domain,
wherein a first RB included in the RB bundling unit is allocated for a specific signal and a second RB included in the RB bundling unit is allocated for a data channel,
wherein, for the first RB, a DMRS collides with the specific signal at a first symbol in the time domain, the DMRS is shifted to a second symbol based on the collision, and
wherein, for the second RB, a symbol location of a DMRS for the data channel, where there is no collision, is shifted based on a location of the second symbol,
transmit, to the terminal, information on the shifted symbol location of the DMRS for the data channel, and
transmit, to the terminal, the DMRS for the data channel on the shifted symbol location.

### Claim 13 (depends on 12)

The base station of claim 12, wherein the DMRS on the first symbol is shifted until the collision does not occur.

### Claim 14

A terminal configured for receiving a Demodulation Reference signal (DMRS) in a wireless communication system, the terminal comprising:
a radio frequency (RF) transceiver transmitting and receiving a radio signal; and
a processor functionally connected with the RF transceiver,
wherein the processor is configured to:
receive, from a base station, a configuration for resource block (RB) bundling,
wherein an RB bundling unit comprises a plurality of RBs in the frequency domain,
wherein a first RB included in the RB bundling unit is allocated for a specific signal and a second RB included in the RB bundling unit is allocated for a data channel,
wherein, for the first RB, a DMRS collides with the specific signal at a first symbol in the time domain, the DMRS is shifted to a second symbol based on the collision, and
wherein, for the second RB, a symbol location of a DMRS for the data channel, where there is no collision, is shifted based on a location of the second symbol,
receive, from the base station, information on the shifted symbol location of the DMRS for the data channel,
receive, from the base station, the DMRS for the data channel on the shifted symbol location, and
perform a channel estimation using the received DMRS for the data channel.