METHOD AND APPARATUS FOR TRANSMITTING OR RECEIVING REFERENCE SIGNAL IN WIRELESS COMMUNICATION SYSTEM

• US 20150271814A1
• Filed: 09/24/2013
• Published: 09/24/2015
• Est. Priority Date: 09/24/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Park, Hanjun, Kim, Kijun, Park, Jonghyun
• Granted Patent: US 9,554,381 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04L 27/26 Systems using multi-frequency codes H04L27/32 takes precedence
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0026 Division using four or more dimensions
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0082 at predetermined intervals
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A method for transmitting a second demodulation reference signal added to support an additional antenna port (referred to as a “second antenna” hereinafter) in a downlink subframe having an extended cyclic prefix (CP), in which a resource (referred to as a “first resource pattern” hereinafter) to which a first demodulation reference signal will be mapped is configured, through a predetermined number of antenna ports (referred to as a “first antenna” hereinafter) in a wireless communication system includes: specifying positions of resources to which a channel state information reference signal (CSI-RS) is mapped in subframe(s) in which the CSI-RS is not transmitted and a subframe in which the CSI-RS is transmitted on the basis of CSI-RS configuration information; selecting a resource (referred to as a “second resource pattern” hereinafter) to which the second demodulation reference signal will be mapped from resources of the subframe(s) in which the CSI-RS is not transmitted, the resources corresponding to the positions of the resources to which the CSI-RS is mapped; and mapping the second demodulation reference signal to the second resource pattern.

Claims

1. A method in a downlink subframe with an extended cyclic prefix (CP), in which a resource to which a first demodulation reference signal is mapped (referred to as a “

first resource pattern”

hereinafter) is configured, through a predetermined number of antenna ports (referred to as a “

first antenna”

hereinafter) in a wireless communication system, the method for transmitting a second demodulation reference signal added to support an additional antenna port (referred to as a “

second antenna”

hereinafter) to a user equipment (UE) comprising;

.

specifying subframe(s) in which a channel state information reference signal (CSI-RS) is not transmitted and positions of resources to which the CSI-RS is mapped in subframe(s) in which the CSI-RS is transmitted based on CSI-RS configuration information;

selecting a resource to which the second demodulation reference signal is mapped (referred to as a “

second resource pattern”

hereinafter) from among resources of the subframe(s) in which the CSI-RS is not transmitted, the resources corresponding to the positions of the resources to which the CSI-RS is mapped; and

mapping the second demodulation reference signal to the second resource pattern.

2. The method according to claim 1, further comprising transmitting the second resource pattern or CSI-RS configuration information indicating the second resource pattern to the UE.

3. The method according to claim 1, further comprising transmitting information on the number of antenna ports of the second antenna used to transmit the second demodulation reference signal to the UE.

4. The method according to claim 1, wherein the selecting of the second resource pattern comprises selecting a resource having a subcarrier index different from a subcarrier index of a resource to which a cell-specific reference signal is allocated.

5. The method according to claim 1, wherein the mapping of the second demodulation reference signal comprises applying a length-4 OCC to complex-valued modulation symbol(s) for the first demodulation reference signal and complex-valued modulation symbol(s) for the second demodulation reference signal in the direction of the time domain.

6. The method according to claim 1, wherein the second resource pattern is composed of as many resource elements as the number of resource elements constituting the first resource pattern.

7. The method according to claim 1, wherein the mapping of the second demodulation reference signal comprises:

dividing each of the first resource pattern and the second resource pattern into two (2) sub-patterns; and

mapping a complex-valued modulation symbol for the first demodulation reference signal to the first sub-pattern of the first resource pattern, mapping a complex-valued modulation symbol for a third demodulation reference signal, transmitted through a third antenna having as many antenna ports as the number of antenna ports of the first antenna, to the second sub-pattern of the first resource pattern, mapping a complex-valued modulation symbol for the second demodulation reference signal to the first sub-pattern of the second resource pattern, and mapping a complex-valued modulation symbol for a fourth demodulation reference signal, transmitted through a fourth antenna having as many antenna ports as the number of antenna ports of the second antenna, to the second sub-pattern of the second resource pattern,

wherein the first resource pattern is divided into the two (2) sub-patterns such that the two (2) sub-patterns have the same frequency domain density and the second resource pattern is divided into the two (2) sub-patterns such that the sub-patterns have the same frequency domain density.

8. The method according to claim 1, wherein the second resource pattern includes at least one of RE pairs positioned at (3x+k′

,

     4) and (3x+k′

,

     5) in each slot of a physical resource block (PRB) pair in the subframe, wherein x=0, 1, 2 and 3, k′

=0 or 2 if n_s mod 2=0, k′

=0 or 1 if n_s mod 2=1, n_s denotes a slot index, and (m, n)=(subcarrier index, OFDM symbol index) in each slot of the PRB pair.

9. A method in a downlink subframe with an extended CP, in which a resource to which a first demodulation reference signal is mapped (referred to as a “

first resource pattern”

hereinafter) is configured, through a predetermined number of antenna ports (referred to as a “

first antenna”

hereinafter) in a wireless communication system, the method for receiving a second demodulation reference signal added to support an additional antenna port (referred to as a “

second antenna”

hereinafter) comprising;

receiving the second demodulation reference signal in a resource for the second demodulation reference signal(referred to as a “

second resource pattern”

hereinafter), selected from resources in subframe(s) in which a CSI-RS is not transmitted, the resources corresponding to positions of resources to which the CSI-RS is mapped in subframe(s) in which the CSI-RS is transmitted,

wherein the subframe(s) in which a CSI-RS is not transmitted and the positions of the resources to which the CSI-RS is mapped are specified based on CSI-RS configuration information.

10. An eNB, in a downlink subframe with an extended CP, in which a resource to which a first demodulation reference signal is mapped (referred to as a “

first resource pattern”

hereinafter) is configured, through a predetermined number of antenna ports (referred to as a “

first antenna”

hereinafter) in a wireless communication system, the eNB configured to transmit a second demodulation reference signal added to support an additional antenna port (referred to as a “

second antenna”

hereinafter) to a user equipment (UE), the eNB comprising;

a radio frequency (RF) unit; and

a processor configured to control the RF unit,

wherein the processor is configured to specify subframe(s) in which a channel state information reference signal (CSI-RS) is not transmitted and positions of resources to which the CSI-RS is mapped in subframe(s) in which the CSI-RS is transmitted based on CSI-RS configuration information, to select a resource to which the second demodulation reference signal is mapped (referred to as a “

second resource pattern”

hereinafter) from among resources of the subframe(s) in which the CSI-RS is not transmitted, the resources corresponding to the positions of the resources to which the CSI-RS is mapped, and to map the second demodulation reference signal to the second resource pattern.

11. A UE, in a downlink subframe with an extended CP, in which a resource to which a first demodulation reference signal is mapped (referred to as a “

first resource pattern”

hereinafter) is configured, through a predetermined number of antenna ports (referred to as a “

first antenna”

hereinafter) in a wireless communication system, the UE configured to receive a second demodulation reference signal added to support an additional antenna port (referred to as a “

second antenna”

hereinafter), the UE comprising;

an RF unit; and

a processor configured to control the RF unit,

wherein the processor is configured to receive the second demodulation reference signal in a resource for the second demodulation reference signal(referred to as a “

second resource pattern”

hereinafter), selected from resources in subframe(s) in which a CSI-RS is not transmitted, the resources corresponding to positions of resources to which the CSI-RS is mapped in subframe(s) in which the CSI-RS is transmitted,

wherein the subframe(s) in which a CSI-RS is not transmitted and the positions of the resources to which the CSI-RS is mapped are specified based on CSI-RS configuration information.