METHOD FOR TRANSMITTING DATA USING CYCLIC DELAY DIVERSITY

• US 20100322349A1
• Filed: 10/23/2007
• Published: 12/23/2010
• Est. Priority Date: 10/23/2006
• Status: Abandoned Application

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Ko, Hyun Soo, Ihm, Bin Chul, Lee, Moon Il, Lee, Wook Bong, Chang, Jae Won
• Application Number:
  US12/446,565
• Publication Number:
  US 20100322349A1
• Time in Patent Office: Days
• US Class Current: 375/299
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04L 27/2602 Signal structure

Abstract

A method of transmitting data using cyclic delay in a multi-antenna system using a plurality of subcarriers is disclosed. Data is transmitted through a phase shift based precoding scheme enhanced from a related art phase shift diversity and a related art precoding scheme. A generalized cyclic delay diversity scheme is selectively applied to a phase shift based precoding scheme or a related art precoding scheme executed on a frequency domain is transferred to a time domain to be applied as a generalized cyclic delay diversity scheme. Accordingly, complexity of a receiver is reduced and communication efficiency can be enhanced.

Claims

1. A method of transmitting signal in MIMO (multiple-input multiple-output)-OFDM (orthogonal frequency division multiplexing) system, the method comprising:

spatial processing an OFDM symbol corresponding to each of the subcarriers on a frequency domain with considering time variable element;

transforming the spatial processed OFDM symbol into a transmission signal on a time domain; and

transmitting the transmission signal.

2. The method of claim 1, further comprising adding a first pilot symbol corresponding to each antenna to the spatial-processed OFDM signal.

3. The method of claim 1, further comprising at least one of multiplying the transmission signal by a plurality of per-antenna weight;

and applying a prescribed cyclic delay to the transmission signal.

19. The method of claim 2, further comprising at least one of multiplying the transmission signal by a plurality of per-antenna weight;

and applying a prescribed cyclic delay to the transmission signal.

4. A method of transmitting signal in MIMO (multiple-input multiple-output)-OFDM (orthogonal frequency division multiplexing) system, the method comprising:

performing precoding on OFDM symbols respectively corresponding to a plurality of the subcarriers on a frequency domain;

transforming the precoded OFDM symbols into per-antenna signals on a time domain;

applying a prescribed cyclic delay to each of the per-antenna signals; and

transmitting the per-antenna signals.

5. The method of claim 4, further comprising adding a first pilot symbol corresponding to each antenna to each of the precoded OFDM symbols.

6. The method of claim 4, further comprising adding a second pilot symbol transformed into the time domain to each of the cyclic-delayed per-antenna signals.

7. A method of transmitting signal in MIMO (multiple-input multiple-output)-OFDM (orthogonal frequency division multiplexing) system, the method comprising:

determining a phase shift based precoding matrix by multiplying a first matrix for a phase shift by a second matrix for transforming the first matrix into a unitary matrix;

phase shift based precoding by multiplying OFDM symbols by the determined phase shift based precoding matrix corresponding to each of a plurality of the subcarriers;

transforming the phase shift based precoded OFDM symbols into transmission signals on a time domain;

applying a prescribed cyclic delay to each of the transmission signals; and

transmitting the cyclic delayed transmission signals.

8. The method of claim 7, further comprising multiplying each of the transmission signals by a plurality of per-antenna weight.

9. The method of claim 8, further comprising adding a first pilot symbol corresponding to each antenna to each of the phase shift based precoded OFDM signals.

10. The method of claim 7, further comprising adding a second pilot symbol transformed into the time domain to each of the cyclic-delayed transmission signals.

11. The method of claim 7, wherein the phase shift based precoding matrix is represented as

12. A method of transmitting signal in a multi-antenna system, comprising:

performing spatial processing associated with multi-antennas on each data stream to be transmitted via at least one of the multi-antennas;

performing a transmission power allocation precoding on the spatial processed data stream to control transmission power for the multi-antennas;

transforming the transmission power allocation precoded data stream into a per-antenna signal on a time domain; and

transmitting the per-antenna signal via at least one of the multi-antennas.

13. The method of claim 12, further comprising at least one of:

applying phase shift diversity on the spatial processed data stream; and

applying cyclic delay diversity on the per-antenna signal.

14. The method of claim 13, wherein the phase shift diversity applies a large cyclic delay value and wherein the cyclic delay diversity applies a small cyclic delay value.

15. The method of claim 12, further comprising at least one of:

adding a first pilot symbol to the spatial processed data stream;

adding a second pilot symbol to the transmission power allocation precoded data stream; and

adding a third pilot symbol transformed into the time domain to the per-antenna signal.

16. The method of claim 12, wherein the transmission power allocation precoding is executed by multiplying a N_t×

N_t unitary matrix (N_t is a number of the multi-antennas).

17. The method of claim 16, wherein the N_t×

N_t unitary matrix is multiplied by a diagonal matrix with a phase value as a variable.

18. The method of claim 12, wherein at least one of the N_t×

N_t unitary and the diagonal matrix is a time variable element.

20. The method of claim 16, wherein at least one of the N_t×

N_t unitary and the diagonal matrix is a time variable element.