Digital frequency hopping in multi-band OFDM

• US 8,320,474 B2
• Filed: 12/06/2006
• Issued: 11/27/2012
• Est. Priority Date: 12/06/2006
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lakkis, Ismail
• Primary Examiner(s): KASSA, ZEWDU A
• Application Number:
  US11/634,761
• Publication Number:
  US 20080137716A1
• Time in Patent Office: 2,183 Days
• Field of Search: 375/135, 375/132, 375/260
• US Class Current: 375/260
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 2001/71367 using a transform
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

A transmitter configured for generating a frequency-hopped OFDM signal comprises a digital Fourier transform circuit, a variable bandpass filter, and a frequency-hopping controller. The digital Fourier transform circuit comprises a plurality of input frequency bins and is configured to modulate complex data symbols onto a plurality of OFDM subcarriers. The variable bandpass filter selects sets of the plurality of input frequency bins for frequency hopping the OFDM subcarriers over a plurality of subbands. The frequency-hopping controller controls the variable bandpass filter with respect to at least one predetermined frequency-hopping pattern. A receiver configured for processing a received frequency-hopped OFDM signal comprises a digital Fourier transform circuit configured to convert a received digital baseband signal into a frequency-domain signal comprising a plurality of OFDM symbols, a variable bandpass filter configured to select sets of the OFDM symbols with respect to predetermined subbands, and a frequency-hopping controller configured to control the variable bandpass filter with respect to a predetermined frequency-hopping pattern.

Claims

1. An apparatus configured for generating a frequency-hopped OFDM signal, comprising:

a digital Fourier transform circuit comprising a plurality of input frequency bins and configured to modulate complex data symbols onto a plurality of OFDM subcarriers,

a variable bandpass filter configured to select sets of the plurality of input frequency bins for frequency hopping the OFDM subcarriers across a plurality of subbands, wherein each set of input frequency bins corresponds to one of the plurality of subbands, and

a frequency-hopping controller configured to control the variable bandpass filter for selecting the sets with respect to at least one predetermined frequency-hopping pattern.

2. The apparatus recited in claim 1, wherein the digital Fourier transform circuit is configured to perform an inverse discrete Fourier transform.

3. The apparatus recited in claim 2, wherein the digital Fourier transform circuit is configured to perform an inverse fast Fourier transform.

4. The apparatus recited in claim 1 is configured to operate in an MB-OFDM system.

5. The apparatus recited in claim 1 is configured as a chipset.

6. The apparatus recited in claim 1, wherein each of the sets of the plurality of input frequency bins corresponds to a respective one of the plurality of subbands, and wherein the controller is configured to control the variable bandpass filter to select input frequency bins of only one of the sets in each symbol interval.

7. A method for performing digital frequency hopping of an OFDM signal, comprising:

performing an inverse discrete Fourier transform, using an apparatus, of a plurality of complex data symbols for producing a wideband OFDM signal having a baseband channel bandwidth comprising a plurality of subbands,

performing variable bandpass filtering on the complex data symbols to selectively couple the complex data symbols to sets of frequency bins of the inverse discrete Fourier transform, wherein each set of frequency bins corresponds to one of the plurality of subbands, and

controlling the variable bandpass filtering with respect to at least one predetermined frequency-hopping pattern.

8. The method recited in claim 7, wherein performing the inverse discrete Fourier transform comprises performing an inverse fast Fourier transform.

9. The method recited in claim 7, wherein the apparatus is configured as a chipset.

10. The method recited in claim 7, wherein the apparatus is configured as a digital computer system.

11. A system configured for performing digital frequency hopping of an OFDM signal, comprising:

means for performing an inverse discrete Fourier transform of a plurality of complex data symbols for producing a wideband OFDM signal having a bandwidth comprising a plurality of subbands,

means for performing variable bandpass filtering on the complex data symbols to selectively couple the complex data symbols to sets of frequency bins of the inverse discrete Fourier transform wherein each set of frequency bins corresponds to one of the plurality of subbands, and

means for controlling the variable bandpass filtering with respect to at least one predetermined frequency-hopping pattern.

12. The system recited in claim 11, wherein the digital Fourier transform means is configured to perform an inverse fast Fourier transform.

13. The system recited in claim 11 is configured to operate in an MB-OFDM system.

14. The system recited in claim 11 is configured as a chipset.

15. An apparatus configured for processing a received frequency-hopped OFDM signal, the receiver comprising:

a digital Fourier transform circuit comprising a plurality of output frequency bins and configured to convert a received digital baseband signal into a frequency-domain signal comprising a plurality of OFDM symbols at the plurality of output frequency bins,

a variable bandpass filter configured to select sets of the plurality of output frequency bins for selecting each of a plurality of subbands, wherein each set corresponds to one of the plurality of subbands of the received frequency-hopped OFDM signal, and

a frequency-hopping controller configured to control the variable bandpass filter for selecting the sets with respect to at least one predetermined frequency-hopping pattern.

16. The apparatus recited in claim 15, wherein the digital Fourier transform circuit is configured to perform a discrete Fourier transform.

17. The apparatus recited in claim 16, wherein the digital Fourier transform circuit is configured to perform a fast Fourier transform.

18. The apparatus recited in claim 15, is further configured to operate in an MB-OFDM system.

19. The apparatus recited in claim 15 is configured as a chipset.

20. A method for processing a received frequency-hopped OFDM signal, comprising:

performing a discrete Fourier transform, using an apparatus, to convert a received digital baseband signal into a frequency-domain signal comprising a plurality of OFDM symbols at a plurality of output frequency bins,

performing variable bandpass filtering on the OFDM symbols to selectively pass the OFDM symbols at sets of the plurality of output frequency bins, wherein each set corresponds to one of a plurality of subbands of the received frequency-hopped OFDM signal, and

controlling the variable bandpass filtering with respect to a predetermined frequency-hopping pattern.

21. The method recited in claim 20, wherein performing the discrete Fourier transform comprises performing a fast Fourier transform.

22. The method recited in claim 20, wherein the apparatus is configured as a chipset.

23. The method recited in claim 20, wherein the apparatus is configured as a digital computer system.

24. A system configured for processing a received frequency-hopped OFDM signal, comprising:

means for performing a discrete Fourier transform of a received digital baseband signal for producing a frequency-domain signal comprising a plurality of OFDM symbols at a plurality of output frequency bins,

means for performing variable bandpass filtering on the OFDM symbols to selectively pass the OFDM symbols at sets of the plurality of output frequency bins, wherein each set corresponds to one of a plurality of subbands of the received frequency-hopped OFDM signal, and

means for controlling the variable bandpass filtering with respect to at least one predetermined frequency-hopping pattern.

25. The system recited in claim 24, wherein the discrete Fourier transform means is configured to perform a fast Fourier transform.

26. The system recited in claim 24 is configured to operate in an MB-OFDM system.

27. The system recited in claim 24 is configured as a chipset.

28. A tangible computer-readable storage medium having instructions stored thereon, when executed by a processor, perform digital frequency hopping in an OFDM signal, comprising:

perform an inverse discrete Fourier transform of a plurality of complex data symbols for producing a wideband OFDM signal having a baseband channel bandwidth comprising a plurality of subbands,

perform variable bandpass filtering on the complex data symbols to selectively couple the complex data symbols to sets of frequency bins of the inverse discrete Fourier transform wherein each set of frequency bins corresponds to one of the plurality of subbands, and

control the variable bandpass filtering with respect to at least one predetermined frequency-hopping pattern.

29. A tangible non-transitory computer-readable storage medium having instructions stored thereon, when executed by a processor, process a received frequency hopped OFDM signal, comprising:

perform a discrete Fourier transform to convert a received digital baseband signal into a frequency-domain signal comprising a plurality of OFDM symbols at a plurality of output frequency bins,

perform variable bandpass filtering on the OFDM symbols to selectively pass the OFDM symbols at sets of the plurality of output frequency bins,

wherein each set corresponds to one of a plurality of subbands of the received frequency-hopped OFDM signal, and

control the variable bandpass filtering with respect to a predetermined frequency-hopping pattern.