Apparatus and method for FT pre-coding of data to reduce PAPR in a multi-carrier wireless network

• US 20060227888A1
• Filed: 03/14/2006
• Published: 10/12/2006
• Est. Priority Date: 04/06/2005
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Khan, Farooq
• Granted Patent: US 7,787,546 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 27/2614 Peak power aspects
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

Abstract

A subscriber station for use in a wireless network capable of communicating according to a multi-carrier protocol, such as OFDM or OFDMA. The subscriber station comprises a size M Fourier Transform (FFT or DFT) block for receiving input symbols and generating M FT pre-coded outputs and a size N inverse Fourier Transform (IFFT or IDFT) block capable of receiving N inputs, where the N inputs include the M FT pre-coded outputs from the size M FT block. The size N IFT block generates N outputs to be transmitted to a base station of the wireless network. The input symbols comprise user data traffic to be transmitted to the base station. The size N IFT block also receives signaling and control information on at least some of N-M inputs. The FT pre-coding generates a time-domain signal that has a relatively lower peak-to-average power ratio (PAPR).

Claims

1. For use in a wireless network, a subscriber station capable of communicating with the wireless network according to a multi-carrier protocol, the subscriber station comprising:

a size M Fourier Transform (FT) block capable of receiving input symbols and generating therefrom M FT pre-coded outputs; and

a size N inverse Fourier Transform (IFT) block capable of receiving N inputs, the N inputs including the M FT pre-coded outputs from the size M FT block, and generating therefrom N outputs to be transmitted to a base station of the wireless network, wherein the size M FT block and the size N IFT block are one of;

     1) a Fast Fourier Transform (FFT) block and an inverse Fast Fourier Transform (IFFT) block; and

     2) a Discrete Fourier Transform (DFT) block and an inverse Discrete Fourier Transform (IDFT) block.

2. The subscriber station as set forth in claim 1, wherein the input symbols comprise user data traffic to be transmitted to the base station.

3. The subscriber station as set forth in claim 2, wherein the size N IFT block receives signaling and control information on at least some of N-M inputs.

4. The subscriber station as set forth in claim 3, wherein the signaling and control information comprises a pilot signal.

5. The subscriber station as set forth in claim 3, wherein the size N IFT block receives only the M FT pre-coded outputs during selected time slots and receives only the signaling and control information during other selected time slots.

6. The subscriber station as set forth in claim 3, wherein the multi-carrier protocol comprises one of orthogonal frequency division multiplexing and orthogonal frequency division multiple access.

7. The subscriber station as set forth in claim 2, wherein the input symbols further comprise a pilot signal.

8. The subscriber station as set forth in claim 7, wherein the size N IFT block receives signaling and control information on at least some of N-M inputs.

9. The subscriber station as set forth in claim 8, wherein the size N IFT block receives only the M FT pre-coded outputs during selected time slots and receives only the signaling and control information during other selected time slots.

10. The subscriber station as set forth in claim 9, wherein the signaling and control information comprises a pilot signal.

11. The subscriber station as set forth in claim 8, wherein the multi-carrier protocol comprises one of orthogonal frequency division multiplexing and orthogonal frequency division multiple access.

12. For use in a subscriber station capable of communicating with a wireless network according to a multi-carrier protocol, a method for reducing the peak-to-average power ration (PAPR) of a radio frequency signal transmitted by the subscriber station to a base station of the wireless network, the method comprising the steps of:

receiving input symbols to be transmitted to the base station;

performing a size M Fourier Transform (FT) operation on the received input symbols to thereby generate M FT pre-coded outputs; and

performing a size N inverse Fourier Transform (IFT) operation on N inputs, the N inputs including the M FT pre-coded outputs, to thereby generate N outputs to be transmitted to the base station, wherein the size M FT operation and the size N IFT operation are one of;

     1) a Fast Fourier Transform (FFT) operation and an inverse Fast Fourier Transform (IFFT) operation; and

     2) a Discrete Fourier Transform (DFT) operation and an inverse Discrete Fourier Transform (IDFT) operation.

13. The method as set forth in claim 12, wherein the input symbols comprise user data traffic to be transmitted to the base station.

14. The method as set forth in claim 13, wherein the size N IFT operation receives signaling and control information on at least some of N-M inputs.

15. The method as set forth in claim 14, wherein the signaling and control information comprises a pilot signal.

16. The method as set forth in claim 14, wherein the size N IFT operation is performed only on the M FT pre-coded outputs during selected time slots and is performed only on the signaling and control information during other selected time slots.

17. The method as set forth in claim 14, wherein the multi-carrier protocol comprises one of orthogonal frequency division multiplexing and orthogonal frequency division multiple access.

18. The method as set forth in claim 13, wherein the input symbols further comprise a pilot signal.

19. The method as set forth in claim 18, wherein the size N IFT operation receives signaling and control information on at least some of N-M inputs.

20. The method as set forth in claim 19, wherein the size N IFT operation is performed only on the M FT pre-coded outputs during selected time slots and is performed only on the signaling and control information during other selected time slots.

21. The method as set forth in claim 20, wherein the signaling and control information comprises a pilot signal.

22. The method as set forth in claim 19, wherein the multi-carrier protocol comprises one of orthogonal frequency division multiplexing and orthogonal frequency division multiple access.

23. A base station for use in a wireless network capable of communicating with subscriber stations according to a multi-carrier protocol, the base station comprising:

down-conversion circuitry capable of receiving incoming radio frequency signals from the subscriber stations and generating therefrom a baseband signal;

a size N Fourier Transform (FT) block capable of receiving the baseband signal on N inputs and performing an FT operation to generate N outputs; and

a size M Inverse Fourier Transform (IFT) block capable of receiving M of the N outputs of the size N FT block and performing a size M IFT operation on the M outputs to generate a plurality of data symbols transmitted by a first one of the subscriber stations, wherein the size N FT block and the size M IFT block are one of;

     1) a Fast Fourier Transform (FFT) block and an inverse Fast Fourier Transform (IFFT) block; and

     2) a Discrete Fourier Transform (DFT) block and an inverse Discrete Fourier Transform (IDFT) block.

24. The base station as set forth in claim 23, wherein the size N FT block generates on at least some of N-M outputs signaling and control information transmitted by the first subscriber station.

25. The base station as set forth in claim 24, wherein the signaling and control information transmitted by the first subscriber station comprises a pilot signal.

26. The base station as set forth in claim 25, further comprising a frequency-domain equalizer capable of receiving the pilot signal transmitted by the first subscriber station and using the pilot signal to perform frequency-domain equalization on the M outputs of the size N FT block prior to the size M IFT operation of the size M IFT block.

27. A method for use in base station of a wireless network capable of communicating with subscriber stations according to a multi-carrier protocol, the method comprising the steps of:

receiving incoming radio frequency (RF) signals from the subscriber stations;

down-converting the incoming RF signals to generate a baseband signal;

performing a size N Fourier Transform (FT) operation on the baseband signal to generate N outputs; and

performing a size M Inverse Fourier Transform (IFT) operation on M of the N outputs of the size N FT operation to generate a plurality of data symbols transmitted by a first one of the subscriber stations, wherein the size N FT operation and the size M IFT operation are one of;

     1) a Fast Fourier Transform (FFT) operation and an inverse Fast Fourier Transform (IFFT) operation; and

     2) a Discrete Fourier Transform (DFT) operation and an inverse Discrete Fourier Transform (IDFT) operation.

28. The method as set forth in claim 27, wherein the size N FT operation generates on at least some of N-M outputs signaling and control information transmitted by the first subscriber station.

29. The method as set forth in claim 28, wherein the signaling and control information transmitted by the first subscriber station comprises a pilot signal.

30. The method as set forth in claim 29, further comprising the step of using the pilot signal to perform frequency-domain equalization on the M outputs of the size N FT operation prior to the size M IFT operation.

31. A wireless network comprising a plurality of base stations capable of communicating with subscriber stations according to a multi-carrier protocol, each of the base stations comprising:

down-conversion circuitry capable of receiving incoming radio frequency signals from the subscriber stations and generating therefrom a baseband signal;

a size N Fourier Transform (FT) block capable of receiving the baseband signal on N inputs and performing an IFT operation to generate N outputs; and

a size M Inverse Fourier Transform (IFT) block capable of receiving M of the N outputs of the size N FT block and performing a size M IFT operation on the M outputs to generate a plurality of data symbols transmitted by a first one of the subscriber stations, wherein the size N FT block and the size M IFT block are one of;

     1) a Fast Fourier Transform (FFT) block and an inverse Fast Fourier Transform (IFFT) block; and

     2) a Discrete Fourier Transform (DFT) block and an inverse Discrete Fourier Transform (IDFT) block.

32. The wireless network as set forth in claim 31, wherein the size N FT block generates on at least some of N-M outputs signaling and control information transmitted by the first subscriber station.

33. The wireless network as set forth in claim 32, wherein the signaling and control information transmitted by the first subscriber station comprises a pilot signal.

34. The wireless network as set forth in claim 33, further comprising a frequency-domain equalizer capable of receiving the pilot signal transmitted by the first subscriber station and using the pilot signal to perform frequency-domain equalization on the M outputs of the size N FT block prior to the size M IFT operation of the size M IFT block.