Method for changing pattern of reference signals according to coherence time variation in wireless communication system and apparatus therefor

Patent metadata

Field	Value
Publication number	US-9893772-B2
Application number	US-201314442358-A
Country	US
Kind code	B2
Filing date	Aug 14, 2013
Priority date	Dec 4, 2012
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A method for transmitting a reference signal to a user equipment at a base station in a wireless communication system is disclosed. The method includes transmitting a control channel and the reference signal having a first pattern for the control channel to the user equipment and transmitting a data channel and the reference signal having a second pattern for the data channel to the user equipment, wherein reference signal density of the second pattern is determined based on a coherence time of the data channel, and the first pattern includes the second pattern.

First claim

The invention claimed is:

1. A method for transmitting a reference signal to a user equipment (UE) at a base station (BS) in a wireless communication system, the method comprising:
transmitting a control channel and the reference signal having a first pattern for the control channel to the UE; and
transmitting a data channel and the reference signal having a second pattern for the data channel to the UE;
wherein reference signal density of the second pattern is determined based on a coherence time of the data channel,
wherein resource elements of the second pattern are included in resource elements of the first pattern in a resource grid, and
wherein the second pattern is determined by eliminating at least one reference signal symbol from the first pattern according to a decreased level of Doppler frequency of the data channel.

2. The method according to claim 1 , further comprising receiving information about the coherence time of the data channel from the UE.

3. The method according to claim 2 , wherein the information about the coherence time of the data channel includes information about effective Doppler spread of the data channel.

4. The method according to claim 1 , further comprising: receiving information about the second pattern from the UE.

5. The method according to claim 1 , further comprising:
calculating effective Doppler spread of the data channel for the UE; and
determining the second pattern based on the effective Doppler spread.

6. The method according to claim 1 , wherein the second pattern is defined as a hierarchical structure in which one or more reference signal symbols are eliminated from the first pattern in a time domain.

7. The method according to claim 1 , wherein time-domain reference signal density of the first pattern is higher than time-domain reference signal density of the second pattern.

8. A method for receiving a reference signal from a base station (BS) at a user equipment (UE) in a wireless communication system, the method comprising:
receiving a control channel and the reference signal having a first pattern for the control channel from the BS; and
receiving a data channel and the reference signal having a second pattern for the data channel from the BS;
wherein reference signal density of the second pattern is determined based on a coherence time of the data channel,
wherein resource elements of the second pattern are included in resource elements of the first pattern in a resource grid, and
wherein the second pattern is determined by eliminating at least one reference signal symbol from the first pattern according to a decreased level of Doppler frequency of the data channel.

9. The method according to claim 8 , further comprising transmitting information about the coherence time of the data channel to the BS.

10. The method according to claim 9 , wherein the information about the coherence time of the data channel includes information about effective Doppler spread of the data channel.

11. The method according to claim 8 , further comprising:
transmitting information about the second pattern to the BS.

12. The method according to claim 8 , wherein the second pattern is defined as a hierarchical structure in which one or more reference signal symbols are eliminated from the first pattern in a time domain.

13. The method according to claim 8 , wherein time-domain reference signal density of the first pattern is higher than time-domain reference signal density of the second pattern.

14. A base station (BS) in a wireless communication system, the BS comprising:
a radio frequency (RF) unit; and
a processor connected with the RF unit and configured to
transmit a control channel and the reference signal having a first pattern for the control channel to a user equipment (UE) and to transmit a data channel and the reference signal having a second pattern for the data channel to the UE,
wherein reference signal density of the second pattern is determined based on a coherence time of the data channel,
wherein resource elements of the second pattern are included in resource elements of the first pattern in a resource grid, and
wherein the second pattern is determined by eliminating at least one reference signal symbol from the first pattern according to a decreased level of Doppler frequency of the data channel.

15. A user equipment (UE) in a wireless communication system, the UE comprising:
a radio frequency (RF) unit; and
a processor connected with the RF unit and configured to
receive a control channel and the reference signal having a first pattern for the control channel from a base station (BS) and to receive a data channel and the reference signal having a second pattern for the data channel from the BS,
wherein reference signal density of the second pattern is determined based on a coherence time of the data channel,
wherein resource elements of the second pattern are included in resource elements of the first pattern in a resource grid, and
wherein the second pattern is determined by eliminating at least one reference signal symbol from the first pattern according to a decreased level of Doppler frequency of the data channel.

Assignees

• Lg Electronics Inc
• Lg Elctronics Inc

Inventors

• Kim Kitae
• Kim Jinmin
• Ko Hyunsoo
• Chung Jaehoon

Classifications

• H04L5/0051

  of dedicated pilots, i.e. pilots destined for a single user or terminal · CPC title

• H04L25/0204

  of multiple channels · CPC title

• H04B7/01 Primary

  Reducing phase shift · CPC title

• H04L5/0053

  Allocation of signalling, i.e. of overhead other than pilot signals · CPC title

• H04L25/0224

  using sounding signals · CPC title