METHOD AND APPARATUS FOR TRANSMITTING REFERENCE SIGNAL IN MULTIPLE ANTENNA SYSTEM

• US 20110116572A1
• Filed: 07/17/2009
• Published: 05/19/2011
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Koo, Ja Ho, Ko, Hyun Soo, Han, Seung Hee, Lee, Moon Il, Chung, Jae Hoon, Kim, So Yeon
• Granted Patent: US 8,442,151 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04B 7/0447 utilizing uniform distribution
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal

Abstract

A method and an apparatus for transmitting a reference signal in a multiple antenna system are provided. The method includes transmitting a common reference signal through N antennas (N<M, where M and N is a natural number), and transmitting a dedicated reference signal through M-N antennas, wherein the common reference signal is transmitted to all user equipments within a cell, and the dedicated reference signal is transmitted to at least one user equipment within the cell.

Claims

1. A method for transmitting a reference signal in a multiple antenna system using M antennas (M>

2, where M is a natural number), the method comprising;

transmitting a common reference signal through N antennas (N<

M); and

transmitting a dedicated reference signal through M-N antennas,

wherein the common reference signal is transmitted to all user equipments within a cell, and the dedicated reference signal is transmitted to at least one user equipment within the cell, and

wherein a resource block is defined for each of the M antennas, the resource block comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols and a plurality of subcarriers, each element of the resource block is a resource element, and the common reference signal or the dedicated reference signal is transmitted through a reference symbol which corresponds to a resource element at a specific position in the resource block for each of the M antennas.

2. The method of claim 1, wherein the common reference signal is generated based on an identifier (ID) of the cell, and the dedicated reference signal is generated based on an ID of the at least one user equipment.

3. The method of claim 1, wherein the dedicated reference signal is transmited in a resource block mapped with a physical downlink shared channel (PDSCH), and information indicating the resource block mapped with the PDSCH is transmitted on a physical downlink control channel (PDCCH).

4. The method of claim 1, wherein the M antennas each has the same number of reference symbols within the resource block.

5. The method of claim 1, wherein the M antennas each has the same number of reference symbols in one OFDM symbol within the resource block.

6. The method of claim 1, further comprising transmitting information indicating the number M and the number N by using a radio resource control (RRC) message.

7. The method of claim 1, wherein information indicating the number M and the number N is masked onto a cyclic redundancy check (CRC) attached to a broadcast channel (BCH) transport block.

8. The method of claim 1, wherein n OFDM symbols (where n is a natural number) within the resource block are mapped to only reference symbols of the N antennas transmitting the common reference signal.

9. The method of claim 8, wherein control information is transmitted on a PDCCH in the n OFDM symbols, and information indicating the number n is transmitted on a physical control format indicator channel (PCFICH).

10. The method of claim 1, wherein a first reference signal for one of the M antennas is generated based on a first sequence, and a second reference signal for the other one of the M antennas is generated based on a second sequence, and wherein the first reference signal and the second reference signal are multiplexed and are transmitted on the same resource element in the resource block.

11. The method of claim 10, wherein the second sequence is obtained by cyclic-shifting the first sequence in a time domain.

12. The method of claim 10, wherein the second sequence is orthogonal to the first sequence.

13. A transmitter comprising:

M antennas (M≦

2, where M is a natural number); and

a reference signal generator generating a common reference signal transmitted through N antennas (N<

M), and generating a dedicated reference signal transmitted through M-N antennas,

wherein the common reference signal is transmitted to all user equipments within a cell, and the dedicated reference signal is transmitted to at least one user equipment within the cell, and

wherein a resource block is defined for each of the M antennas, the resource block comprises a plurality of OFDM symbols and a plurality of subcarriers, each element of the resource block is a resource element, and the common reference signal or the dedicated reference signal is transmitted through a reference symbol which corresponds to a resource element at a specific position on the resource block for each of the M antennas.