TRANSMISSION AND RECEPTION METHOD AND APPARATUS FOR REDUCING PEAK TO AVERAGE POWER RATIO IN ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM

• US 20170134205A1
• Filed: 11/04/2016
• Published: 05/11/2017
• Est. Priority Date: 11/05/2015
• Status: Active Grant

• Current Assignee: Postech Academy-Industry Foundation, Samsung Electronics Co. Ltd.
• Original Assignee: Postech Academy-Industry Foundation, Samsung Electronics Co. Ltd.
• Inventors: Kim, Chan-Hong, Yun, Yeo-Hun, Kim, Jubum, Kim, Minuk, Lee, Eun Ae, Cho, Joon Ho
• Granted Patent: US 9,893,919 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 27/2082 for offset or staggered quadrature phase shift keying
• CPC Class Codes: H04L 27/2623 Reduction thereof by clipping

Abstract

A transmission and reception method and apparatus for reducing a PAPR in an orthogonal frequency division multiplexing (OFDM) system are provided. A transmission method includes performing constellation rotation with respect to L input data symbols, performing L-point DFT spreading and circular extension on the constellation-rotated L data symbols to be K symbols, performing frequency domain (FD) windowing processing by multiplying the K circular-extended data symbols by a circular filter coefficient, and transmitting the processed data symbols.

Claims

1. A transmission method for reducing a peak-to-average power ratio (PAPR) in an orthogonal frequency division multiplexing (OFDM) system, the method comprising:

performing a constellation rotation with respect to L input data symbols;

performing an L-point discrete Fourier transform (DFT) spreading and circular extension on the L constellation-rotated data symbols to be K symbols;

performing a frequency domain (FD) windowing processing by multiplying the K circular-extended data symbols by a circular filter coefficient; and

transmitting the processed data symbols,

wherein L denotes a number of data symbols to be transmitted through a single OFDM symbol, and K denotes a circular filter spreading (CFS)-OFDM spreading factor.

2. The method of claim 1, wherein, when binary phase shift keying (BPSK) is used as a constellation, an optimal phase value θ

_opt for the constellation rotation is determined to be an equation provided below;

3. The method of claim 2, wherein the constellation rotation is performed by applying a shift index (shiftindex) optimized in the BPSK with respect to an element (S)_i,j in a K-by-L circular filter matrix, as shown in an equation provided below:

4. The method of claim 1, wherein, when QPSK is used as a constellation, an optimal phase value θ

_opt for the constellation rotation is determined to be an equation provided below;

5. The method of claim 4, wherein the constellation rotation is performed by applying a shift index (shiftindex) optimized in the QPSK with respect to an element (S)_i,j in a K-by-L circular filter matrix, as shown in an equation provided below:

6. A transmitting apparatus in an orthogonal frequency division multiplexing (OFDM) system, the apparatus comprising:

a transmission module configured to;

perform a constellation rotation with respect to L input data symbols,

execute an L-point discrete DFT spreading and a circular extension on the L constellation-rotated data symbols to be K symbols, and

perform a frequency domain (FD) windowing processing by multiplying the K circular-extended data symbols by a circular filter coefficient,

wherein L denotes a number of data symbols to be transmitted through a single OFDM symbol, and K denotes a circular filter spreading (CFS)-OFDM spreading factor.

7. The apparatus of claim 6, wherein, when binary phase shift keying (BPSK) is used as a constellation, an optimal phase value θ

_opt for the constellation rotation is determined to be an equation provided below;

8. The apparatus of claim 7, wherein the constellation rotation is performed by applying a shift index (shiftindex) optimized in the BPSK with respect to an element (S)_i,j in a K-by-L circular filter matrix, as shown in an equation provided below:

9. The apparatus of claim 6, wherein, when QPSK is used as a constellation, an optimal phase value θ

_opt for the constellation rotation is determined to be an equation provided below;

10. The apparatus of claim 9, wherein the constellation rotation is performed by applying a shift index (shiftindex) optimized in the QPSK with respect to an element (S)_i,j in a K-by-L circular filter matrix, as shown in an equation provided below:

11. A method for operating a base station in an orthogonal frequency division multiplexing (OFDM) system, the method comprising:

performing a constellation rotation with respect to L input data symbols;

performing an L-point discrete Fourier transform (DFT) spreading and circular extension on the L constellation-rotated data symbols to be K symbols;

performing a frequency domain (FD) windowing processing by multiplying the K circular-extended data symbols by a circular filter coefficient; and

transmitting the FD window processing performed data symbols,

wherein L denotes a number of data symbols to be transmitted through a single OFDM symbol, and K denotes a circular filter spreading (CFS)-OFDM spreading factor.

12. The method of claim 11, wherein, when binary phase shift keying (BPSK) is used as a constellation, an optimal phase value for the constellation rotation is determined to be an equation provided below:

13. The method of claim 12, wherein the constellation rotation is performed by applying a shift index (shiftindex) optimized in the BPSK with respect to an element (S)_i,j in a K-by-L circular filter matrix, as shown in an equation provided below:

14. The method of claim 11, wherein, when QPSK is used as a constellation, an optimal phase value θ

_opt for the constellation rotation is determined to be an equation provided below;

15. The method of claim 14, wherein the constellation rotation is performed by applying a shift index (shiftindex) optimized in the QPSK with respect to an element (S)_i,j in a K-by-L circular filter matrix, as shown in an equation provided below:

16. A base station for an orthogonal frequency division multiplexing (OFDM) system, the base station comprising:

a controller configured to;

perform a constellation rotation with respect to L input data symbols,

execute an L-point discrete DFT spreading and a circular extension on the L constellation-rotated data symbols to be K symbols, and

perform a frequency domain (FD) windowing processing by multiplying the K circular-extended data symbols by a circular filter coefficient; and

a transceiver configured to transmit the FD window processing performed data symbols,

wherein L denotes a number of data symbols to be transmitted through a single OFDM symbol, and K denotes a circular filter spreading (CFS)-OFDM spreading factor.

17. The base station of claim 16, wherein, when binary phase shift keying (BPSK) is used as a constellation, an optimal phase value for the constellation rotation is determined to be an equation provided below:

18. The base station of claim 17, wherein the constellation rotation is performed by applying a shift index (shiftindex) optimized in the BPSK with respect to an element (S)_i,j in a K-by-L circular filter matrix, as shown in an equation provided below:

19. The base station of claim 16, wherein, when QPSK is used as a constellation, an optimal phase value θ

_opt for the constellation rotation is determined to be an equation provided below;

20. The base station of claim 19, wherein the constellation rotation is performed by applying a shift index (shiftindex) optimized in the QPSK with respect to an element (S)_i,j in a K-by-L circular filter matrix, as shown in an equation provided below: