Apparatus and method for reducing peak-to-average power ratio in a wireless communication system

• US 20090086848A1
• Filed: 10/01/2008
• Published: 04/02/2009
• Est. Priority Date: 10/01/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Han, Seung-Hee, Yun, Sang-Boh, Lee, Jong-Hyeuk
• Granted Patent: US 8,204,150 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04L 27/2618 Reduction thereof using auxiliary subcarriers
• CPC Class Codes: H04L 27/2623 Reduction thereof by clipping
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0066 Requirements on out-of-channel emissions

Abstract

An apparatus is provided for reducing a peak-to-average power ratio (PAPR) in a wireless communication system having multiple transmit antennas. A symbol generator generates symbols to be transmitted via the multiple transmit antennas, and a PAPR calculator calculates a PAPR value for each symbol. A detector detects a maximum PAPR value among the PAPR values of the symbols. A controller outputs a control signal to reduce a PAPR value of a corresponding symbol when the detected maximum PAPR value exceeds a reference PAPR value. A PAPR reducer reduces the PAPR value of the corresponding symbol upon receipt of the control signal.

Claims

1. An apparatus for reducing a peak-to-average power ratio (PAPR) in a wireless communication system having multiple transmit antennas, the apparatus comprising:

a symbol generator for generating symbols to be transmitted via the multiple transmit antennas;

a PAPR calculator for calculating a PAPR value for each of the generated symbols;

a detector for detecting a maximum PAPR value among the PAPR values of the generated symbols;

a controller for outputting a control signal to reduce a PAPR value of a corresponding symbol when the detected maximum PAPR value exceeds a reference PAPR value; and

a PAPR reducer for reducing the PAPR value of the corresponding symbol upon receipt of the control signal.

2. The apparatus of claim 1, wherein the controller counts a number of PAPR reductions performed by the PAPR reducer, and transfers no control signal for PAPR reduction to the PAPR reducer when the count value exceeds a reference count value.

3. The apparatus of claim 1, wherein the controller counts a number of PAPR reductions performed by the PAPR reducer, and transfers a control signal for stopping a PAPR reduction operation to the PAPR reducer when the count value exceeds a reference count value.

4. The apparatus of claim 1, wherein the symbols are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

5. The apparatus of claim 1, wherein the PAPR reducer reduces a PAPR value of a symbol using at least one from the group consisting of a clipping &

filtering technique, a selective mapping (SLM) technique, a partial transmit sequence (PTS) technique, an interleaving technique, and a tone reservation technique.

6. The apparatus of claim 1, wherein the controller generates no control signal for PAPR reduction for a corresponding symbol when the detected maximum PAPR value is less than the reference PAPR value.

7. The apparatus of claim 1, further comprising:

a buffer for storing the corresponding symbol, a PAPR value of which is reduced by the PAPR reducer.

8. A method for reducing a peak-to-average power ratio (PAPR) in a wireless communication system having multiple transmit antennas, the method comprising:

generating symbols to be transmitted via the multiple transmit antennas;

calculating a PAPR value for each of the generated symbols;

detecting a maximum PAPR value among the calculated PAPR values of the symbols; and

reducing the PAPR value of the corresponding symbol when the detected maximum PAPR value exceeds a reference PAPR value.

9. The method of claim 8, wherein reducing the PAPR value of the corresponding symbol comprises:

counting a number of PAPR reductions, and repeating the PAPR reduction until the count value exceeds a reference count value.

10. The method of claim 8, wherein the symbols are Orthogonal Frequency Division Multiplexing (OFDM) symbols.

11. The method of claim 8, wherein a technique used for PAPR reduction for the corresponding symbol includes at least one from the group consisting of a clipping &

filtering technique, a selective mapping (SLM) technique, a partial transmit sequence (PTS) technique, an interleaving technique, and a tone reservation technique.

12. The method of claim 8, further comprising:

refraining from reducing a PAPR value of the corresponding symbol when the detected maximum PAPR value is less than the reference PAPR value.

13. The method of claim 8, further comprising:

storing the corresponding symbol, a PAPR value of which is reduced.

14. A method for reducing a peak-to-average power ratio (PAPR) in a wireless communication system having multiple transmit antennas, the method comprising:

generating one or more symbols to be transmitted through the multiple transmit antennas;

calculating a PAPR value for each of the one or more symbols;

determining a maximum PAPR value among the PAPR values of the symbols; and

transmitting a control signal to reduce a PAPR value of a corresponding symbol when the maximum PAPR value exceeds a reference PAPR value.

15. The method of claim 14, further comprising:

reducing the PAPR value of the corresponding symbol upon receipt of the control signal.

16. The method of claim 15, wherein reducing the PAPR value of the corresponding symbol comprises:

counting a number of PAPR reductions, and repeating the PAPR reduction until the count value exceeds a reference count value.

17. The method of claim 14, wherein the symbol is an Orthogonal Frequency Division Multiplexing (OFDM) symbol.

18. The method of claim 14, wherein a technique used for PAPR reduction for the corresponding symbol includes at least one from the group consisting of a clipping &

filtering technique, a selective mapping (SLM) technique, a partial transmit sequence (PTS) technique, an interleaving technique, and a tone reservation technique.

19. The method of claim 14, further comprising:

refraining from reducing a PAPR value of the corresponding symbol when the detected maximum PAPR value is less than the reference PAPR value.

20. The method of claim 14, further comprising:

storing the corresponding symbol, a PAPR value of which is reduced.