METHOD AND APPARATUS FOR TRANSMITTING REFERENCE SIGNAL IN MULTI-ANTENNA SYSTEM

• US 20150172021A1
• Filed: 02/27/2015
• Published: 06/18/2015
• Est. Priority Date: 05/21/2009
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: NOH, Min Seok, CHUNG, Jae Hoon, KWON, Yeong Hyeon, KO, Hyun Soo, HAN, Seung Hee, LEE, Moon Il
• Granted Patent: US 9,219,587 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0613 using simultaneous transmission H04B7/0686 takes precedence
• CPC Class Codes: H04B 7/0684 using different training sequences per antenna
• CPC Class Codes: H04J 13/0074 Code shifting or hopping
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 27/26035 Maintenance of orthogonality, e.g. for signals exchanged between cells or users, or by using covering codes or sequences using different training sequence per antenna H04B7/0684; code allocation H04J13/16
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0026 Division using four or more dimensions
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A method and apparatus are described for transmitting a reference signal in a multi-antenna system. A terminal generates a plurality of reference signal sequences to which cyclic shift values different from each other are allocated, generates an orthogonal frequency division multiplexing (OFDM) symbol to which the plurality of reference signal sequences are mapped, and transmits the OFDM symbol to a base station through a plurality of antennas. The respective cyclic shift values allocated to the respective reference signal sequences are determined on the basis of a parameter n indicated by a cyclic shift field transmitted from a physical downlink control channel (PDCCH).

Claims

1. A method for transmitting, by a user equipment (UE), a demodulation reference signal (DMRS) for a physical uplink shared channel (PUSCH) in a wireless communication system, the method comprising:

receiving a cyclic shift field through a physical downlink control channel (PDCCH) from a base station, wherein the cyclic shift field indicates first, second, third and fourth cyclic shifts;

generating a first DMRS sequence, which is associated with a first layer, by using the first cyclic shift;

generating a second DMRS sequence, which is associated with a second layer, by using the second cyclic shift;

generating a third DMRS sequence, which is associated with a third layer, by using the third cyclic shift, wherein the third DMRS sequenced mapped in a second slot among two slots is multiplied with −

1;

generating a fourth DMRS sequence, which is associated with a fourth layer, by using the fourth cyclic shift, wherein the fourth DMRS sequenced mapped in the second slot among the two slots is multiplied with −

1; and

transmitting the first, second, third and fourth DMRS sequences to the base station,

wherein the first and second cyclic shifts are separated by a maximum value corresponding to a total number of possible cyclic shifts, and

wherein the third and fourth cyclic shifts are separated by the maximum value corresponding to the total number of possible cyclic shifts.

2. The method of claim 1, wherein the third cyclic shift is separated from each of the first and second cyclic shifts by a medium value between the first and second cyclic shifts.

3. The method of claim 1, wherein the total number of possible cyclic shifts is 12.

4. The method of claim 1, wherein the maximum value corresponding to the total number of possible cyclic shifts is 6.

5. The method of claim 1, wherein the cyclic shift field has a length of 3 bits.

6. The method of claim 1, wherein the cyclic shift field is received via a downlink control information (DCI) format.

7. A user equipment (UE) configured to transmit a demodulation reference signal (DMRS) for a physical uplink shared channel (PUSCH) in a wireless communication system, the UE comprising:

a radio frequency (RF) unit configured to transmit or receive a radio signal, and

a processor coupled to the RF unit, and configured to;

receive a cyclic shift field through a physical downlink control channel (PDCCH) from a base station, wherein the cyclic shift field indicates first, second, third and fourth cyclic shifts;

generate a first DMRS sequence, which is associated with a first layer, by using the first cyclic shift;

generate a second DMRS sequence, which is associated with a second layer, by using the second cyclic shift;

generate a third DMRS sequence, which is associated with a third layer, by using the third cyclic shift, wherein the third DMRS sequenced mapped in a second slot among two slots is multiplied with −

1;

generate a fourth DMRS sequence, which is associated with a fourth layer, by using the fourth cyclic shift, wherein the fourth DMRS sequenced mapped in the second slot among the two slots is multiplied with −

1; and

transmit the first, second, third and fourth DMRS sequences to the base station,

wherein the first and second cyclic shifts are separated by a maximum value corresponding to a total number of possible cyclic shifts, and

wherein the third and fourth cyclic shifts are separated by the maximum value corresponding to the total number of possible cyclic shifts.

8. The UE of claim 7, wherein the third cyclic shift is separated from each of the first and second cyclic shifts by a medium value between the first and second cyclic shifts.

9. The UE of claim 7, wherein the total number of possible cyclic shifts is 12.

10. The UE of claim 7, wherein the maximum value corresponding to the total number of possible cyclic shifts is 6.

11. The UE of claim 7, wherein the cyclic shift field has a length of 3 bits.

12. The UE of claim 7, wherein the cyclic shift field is received via a downlink control information (DCI) format.