Method and apparatus for transmitting or receiving an additional demodulation reference signal based on a channel state information reference signal resource pattern

• US 9,554,381 B2
• Filed: 09/24/2013
• Issued: 01/24/2017
• 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
• Primary Examiner(s): Musa, Abdelnabi O
• Application Number:
  US14/430,472
• Publication Number:
  US 20150271814A1
• Time in Patent Office: 1,218 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 resource pattern for mapping a first demodulation reference signal (DM-RS) is configured, through a first set of antenna ports in a wireless communication system, the method for transmitting a second DM-RS which is mapped to different resources to which the first DM-RS is mapped, the second DM-RS being added to support a second set of antenna ports to a user equipment (UE), the method 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 second resource pattern for mapping the second DM-RS from among resources, corresponding to the specified positions of the resources, in the subframe(s) in which the CSI-RS is not transmitted; and

mapping the second DM-RS to the second resource pattern in the subframe(s) in which the CSI-RS is not transmitted.

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 a number of antenna ports in the second set used to transmit the second DM-RS 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 DM-RS comprises applying a length-4 orthogonal cover code (OCC) to complex-valued modulation symbol(s) for the first DM-RS and complex-valued modulation symbol(s) for the second DM-RS in a direction of a time domain.

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

7. The method according to claim 1, wherein the mapping of the second DM-RS comprises:

dividing each of the first resource pattern and the second resource pattern into a first sub-pattern and a second sub-pattern; and

mapping a complex-valued modulation symbol for the first DM-RS to the first sub-pattern of the first resource pattern;

mapping a complex-valued modulation symbol for a third DM-RS, transmitted through a third set of antenna ports having as many antenna ports as a number of antenna ports in the first set, to the second sub-pattern of the first resource pattern,

mapping a complex-valued modulation symbol for the second DM-RS to the first sub-pattern of the second resource pattern; and

mapping a complex-valued modulation symbol for a fourth DM-RS, transmitted through a fourth set of antenna ports having as many antenna ports as a number of antenna ports in the second set, to the second sub-pattern of the second resource pattern,

wherein the first resource pattern is divided into the first sub-pattern and the second sub-pattern such that the first sub-pattern and the second sub-pattern have a same frequency domain density and the second resource pattern is divided into a first sub-pattern and a second sub-pattern such that the first sub-pattern and the second sub-pattern of the second resource pattern have a same frequency domain density.

8. The method according to claim 1, wherein the second resource pattern includes at least one of resource element (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, orthogonal frequency division multiplexing (OFDM) symbol index) in each slot of the PRB pair.

9. A method in a downlink subframe with an extended cyclic prefix (CP), in which a resource to which a first resource pattern for mapping a first demodulation reference signal (DM-RS) is mapped is configured, through a first set of antenna ports in a wireless communication system, the method for receiving a second DM-RS which is mapped to different resources to which the first DM-RS is mapped, the second DM-RS being added to support a second set of antenna ports, the method comprising:

receiving the second DM-RS on a resource corresponding to a second resource pattern,

wherein the second resource pattern is selected for mapping the second DM-RS from resources, corresponding to positions of the resources, in subframe(s) in which a channel state information reference signal (CSI-RS) is not transmitted, and

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

10. An evolved Node-B (eNB), in a downlink subframe with an extended cyclic prefix (CP), in which a resource to which a first resource pattern for mapping a first demodulation reference signal (DM-RS) is mapped is configured, through a first set of antenna ports in a wireless communication system, the eNB configured to transmit a second DM-RS which is mapped to different resources to which the first DM-RS is mapped, the second DM-RS being added to support a second set of antenna ports to a user equipment (UE), the eNB comprising:

a memory; and

a processor connected to the memory and 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,

select a second resource pattern for mapping the second DM-RS from among resources, corresponding to the specified positions of the resources, in the subframe(s) in which the CSI-RS is not transmitted, and

map the second DM-RS to the second resource pattern in the subframe(s) in which the CSI-RS is not transmitted.

11. A user equipment (UE), in a downlink subframe with an extended cyclic prefix (CP), in which a resource to which a first resource pattern for mapping a first demodulation reference signal (DM-RS) is mapped is configured, through a first set of antenna ports in a wireless communication system, the UE configured to receive a second DM-RS which is mapped to different resources to which the first DM-RS is mapped, the second DM-RS being added to support a second set of antenna ports, the UE comprising:

a memory; and

a processor connected to the memory and configured to;

receive the second DM-RS on a resource corresponding to a second resource pattern,

wherein the second resource pattern is selected for mapping the second DM-RS from among resources, corresponding to positions of the resources, in subframe(s) in which a channel state information reference signal (CSI-RS) is not transmitted, and

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