Method of transmitting reference signals in a wireless communication having multiple antennas

• US 9,385,906 B2
• Filed: 04/05/2013
• Issued: 07/05/2016
• Est. Priority Date: 09/26/2008
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Noh, Yu Jin, Lee, Dae Won, Kim, Bong Hoe, Kim, Ki Jun
• Primary Examiner(s): Huynh, Dung B
• Application Number:
  US13/857,962
• Publication Number:
  US 20130230123A1
• Time in Patent Office: 1,187 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0226 sounding signals per se
• CPC Class Codes: H04L 25/0248 Eigen-space methods
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03866 using scrambling
• CPC Class Codes: H04L 27/2627 Modulators
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0092 Indication of how the channel is divided

Abstract

A method of transmitting signals by a transmitting end in a wireless communication system comprises sharing control information related to reference signal with a receiving end; generating one or more precoded reference signals considering a given rank; allocating the one or more precoded reference signals to have a specific pattern within a subframe, wherein the specific pattern is varied depending on the control information; and transmitting the subframe through multiple antennas to the receiving end.

Claims

1. A method of transmitting uplink (UL) signals using a plurality of subcarriers by a user equipment (UE) in a wireless communication system, the method comprising:

generating two or more UL demodulation reference signals (DMRSs) for two or more data layers including a first layer and a second layer;

mapping the two or more UL DMRSs to resource elements (REs) on an UL subframe per antenna ports used for transmitting the two or more data layers,

transmitting the two or more UL DMRSs,

wherein when a rank is 3 or more, the two or more UL DMRSs are mapped non-continuously in a frequency domain, and are transmitted based on an orthogonal frequency division multiple access (OFDMA) scheme, and

wherein when the rank is 2 or less, the two or more UL DMRSs are mapped continuously in the frequency domain, and are transmitted based on a single carrier-frequency division multiple access (SC-FDMA) scheme.

2. The method of claim 1, wherein the two or more UL DMRSs are staggered within the UL subframe or slot.

3. The method of claim 1,

wherein a first UL DMRS for the first layer and a second UL DMRS for the second layer among the two or more UL DMRSs are mapped to a same set of REs based on a combination of code division multiplexing and frequency domain cyclic shifting, the two or more UL DMRSs mapped on only one predetermined symbol per the each slot, and

wherein the same set of REs includes REs separated by N subcarriers per slot, and N is equal to 2, 3 or 4.

4. The method of claim 1, wherein the two or more UL DMRSs mapped on a predetermined symbol cover all subcarriers of one or more resource blocks.

5. The method of claim 1, wherein the two or more UL DMRSs are different from UL data and are precoded for UL multiple-input and multiple-output (MIMO).

6. A user equipment (UE) for transmitting uplink signals using a plurality of subcarriers in a wireless communication system, the UE comprising:

a processor adapted to generate two or more UL demodulation reference signals (DMRSs) for two or more data layers including a first layer and a second layer, and to map the two or more UL DMRSs to resource elements (REs) on an UL subframe per antenna ports used for transmitting the two or more data layers; and

a transmitter adapted to transmit the two or more UL DMRSs,

wherein when a rank is 3 or more, the two or more UL DMRSs are mapped non-continuously in a frequency domain, and are transmitted based on an orthogonal frequency division multiple access (OFDMA) scheme, and

wherein when the rank is 2 or less, the two or more UL DMRSs are mapped continuously in the frequency domain, and are transmitted based on a single carrier-frequency division multiple access (SC-FDMA) scheme.

7. The UE of claim 6, wherein the two or more UL DMRSs are staggered within the UL subframe or slot.

8. The UE of claim 6,

wherein a first UL DMRS for the first layer and a second UL DMRS for the second layer among the two or more UL DMRSs are mapped to a same set of REs based on a combination of code division multiplexing and frequency domain cyclic shifting, the two or more UL DMRSs mapped on only one predetermined symbol per the each slot, and

wherein the same set of REs includes REs separated by N subcarriers per slot, and N is equal to 2, 3 or 4.

9. The UE of claim 6, wherein the two or more UL DMRSs mapped on a predetermined symbol cover all subcarriers of one or more resource blocks.