SYSTEMS AND METHODS FOR IMPLEMENTING PEAK-TO-AVERAGE POWER RATIO REDUCTION FOR OFDMA MODULATION

• US 20140169188A1
• Filed: 12/17/2012
• Published: 06/19/2014
• Est. Priority Date: 12/17/2012
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Arambepola, Bernard, Shukla, Parveen, Hewavithana, Thushara, Gamage, Sahan
• Granted Patent: US 8,982,724 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 27/2614 Peak power aspects
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

A system and method are provided for implementing a peak-to-average power ratio (PAPR) reduction scheme for Orthogonal Frequency-Division Multiple Access (OFDMA) modulation. A unique PAPR reduction scheme for OFDMA modulation for systems operated according to a DOCSIS standard achieves results similar to those attributable to tone reservation schemes in a manner that does not negatively affect an amount of available data capacity, particularly in implementations with limited numbers of subcarriers. The disclosed systems and methods are particularly adaptable to next generation cable gateways and/or next generation cable modems. These next generation cable gateways and/or cable modems may find particular utility in advanced hybrid fiber/coaxial cable systems. The adaptable cable gateways/modems may include a cable gateway system-on-chip (SOC) configuration. The disclosed schemes may be applicable to OFDM modulation. For OFDM, however, the known tone reservation algorithms also may be employed.

Claims

1. A communicating system, comprising:

a first communicating device; and

a processing device associated with the first communicating device, the processing device being programmed to

identify bits in a plurality of subcarriers of a data signal that are set for peak-to-average power ratio (PAPR) reduction;

determine which values for the PAPR reduction bits in each of the plurality of subcarriers yield a smallest peak amplitude for the each of the plurality of subcarriers; and

set the PAPR reduction bits to the determined values.

2. The communicating system of claim 1, the plurality of subcarriers being pre-defined.

3. The communicating system of claim 2, the PAPR reduction bits in the plurality of subcarriers being a pre-defined pair of bits in at least one of the plurality of pre-defined subcarriers.

4. The communicating system of claim 1, the first communicating device transmitting a data signal that includes the plurality of subcarriers with the PAPR reduction bits in each of the plurality of subcarriers set to the determined values.

5. The communicating system of claim 1, the processing device being further programmed to

determine a number M of the plurality of subcarriers that include PAPR reduction bits;

sequentially identify, evaluate and set the PAPR reduction bits for a first and subsequent one of the plurality of subcarriers until the PAPR reduction bits in all of the number M subcarriers are set.

6. The communicating system of claim 1, the PAPR reduction bits in each of the plurality of subcarriers being most significant bits in each of the plurality of subcarriers.

7. The communicating system of claim 1, the plurality of subcarriers being randomly located in a data symbol.

8. The communicating system of claim 1, the processing device determining which values for the PAPR reduction bits in each of the plurality of subcarriers yield the smallest peak amplitude for the each of the plurality of subcarriers by applying an Inverse Fast Fourier Transform to each combination of values for the PAPR reduction bits.

9. The communicating system of claim 1, the first communicating device employing Orthogonal Frequency-Division Multiple Access modulation.

10. The communicating system of claim 1, the first communicating device being one of a cable modem and a cable gateway.

11. The communicating system of claim 10, the one of the cable modem and cable gateway operating according to a Data Over Cable Service Interface Specification standard.

12. A method to reduce a peak-to-average power ratio (PAPR), comprising:

identifying bits in a plurality of subcarriers of a data signal that are set for PAPR reduction;

determining, with a processor, which values for the PAPR reduction bits in each of the plurality of subcarriers yield a smallest peak amplitude for the each of the plurality of subcarriers;

setting the PAPR reduction bits to the determined values; and

transmitting, with a first communicating device, the data signal that includes the plurality of subcarriers with the PAPR reduction bits in each of the plurality subcarriers set to the determined values.

13. The method of claim 12, the plurality of subcarriers being pre-defined.

14. The method of claim 13, the PAPR reduction bits in the plurality of subcarriers being a pre-defined pair of bits in at least one of the plurality of pre-defined subcarriers.

15. The method of claim 12, the data signal being received by a second communicating device, the data signal being processed by the second communicating device by discarding the PAPR reduction bits in the plurality of subcarriers.

16. The method of claim 12, further comprising:

determining a number M of the plurality of subcarriers that include PAPR reduction bits; and

sequentially executing the identifying, the evaluating and the setting of the PAPR reduction bits for a first and subsequent one of the plurality of subcarriers until the PAPR reduction bits in all of the number M of subcarriers are set.

17. The method of claim 12, the PAPR reduction bits in each of the plurality of subcarriers being most significant bits in each of the plurality of subcarriers.

18. The method of claim 12, the plurality of subcarriers being randomly located in a data symbol.

19. The method of claim 12, the determining which values for the PAPR reduction bits in each of the plurality of subcarriers yield the smallest peak amplitude for each of the plurality of subcarriers comprising applying an Inverse Fast Fourier Transform to each combination of values for the PAPR reduction bits.

20. The method of claim 12, the data signal employing Orthogonal Frequency-Division Multiple Access modulation.

21. The method of claim 12, the first communicating device being one of a cable modem and a cable gateway.

22. The method of claim 21, the one of the cable modem and cable gateway operating according to a Data Over Cable Service Interface Specification standard.

23. A non-transitory computer-readable medium storing computer-readable instructions which, when executed by a processor, cause the processor to execute a method to reduce a peak-to-average power ratio (PAPR), comprising:

identifying bits in a plurality of subcarriers of a data signal that are set for PAPR reduction;

determining which values for the PAPR reduction bits in each of the plurality of subcarriers to determine which values for the PAPR reduction bits yield a smallest peak amplitude for the each of the plurality of subcarriers;

setting the PAPR reduction bits to the determined values; and

directing transmitting, with a first communicating device, of the data signal that includes the plurality of subcarriers with the PAPR reduction bits in each of the plurality subcarriers set to the determined values.

24. The non-transitory computer-readable medium of claim 23, the plurality of subcarriers being pre-defined.

25. The non-transitory computer-readable medium of claim 24, the PAPR reduction bits in the plurality of subcarriers being a pre-defined pair of bits in at least one of the plurality of pre-defined subcarriers.

26. The non-transitory computer-readable medium of claim 23, the data signal being received by a second communicating device, the data signal being processed by the second communicating device by discarding the PAPR reduction bits in the plurality of subcarriers.

27. The non-transitory computer-readable medium of claim 23, the method further comprising:

determining a number M of the plurality of subcarriers that include PAPR reduction bits; and

sequentially executing the identifying, the evaluating and the setting of the PAPR reduction bits for a first and subsequent one of the plurality of subcarriers until the PAPR reduction bits in all of the number M of subcarriers are set.

28. The non-transitory computer-readable medium of claim 23, the PAPR reduction bits in each of the plurality of subcarriers being most significant bits in each of the plurality of subcarriers.

29. The non-transitory computer-readable medium of claim 23, the plurality of subcarriers being randomly located in a data symbol.

30. The non-transitory computer-readable medium of claim 23, the determining which values for the PAPR reduction bits in each of the plurality of subcarriers yield the smallest peak amplitude for each of the plurality of subcarriers comprising applying an Inverse Fast Fourier Transform to each combination of values for the PAPR reduction bits.

31. The non-transitory computer-readable medium of claim 23, the data signal employing Orthogonal Frequency-Division Multiple Access modulation.

32. The non-transitory computer-readable medium of claim 23, the first communicating device being one of a cable modem and a cable gateway.

33. The non-transitory computer-readable medium of claim 32, the one of the cable modem and cable gateway operating according to a Data Over Cable Service Interface Specification standard.