Granted Patent B2

US 10,383,122 · App. 15/728,916 · Granted Aug 13, 2019

Inventors: Tao Yu (Andover, MA); Douglas Keith Rosich (North Reading, MA); Weidong Chen (Boxborough, MA)

Assignee: Casa Systems, Inc.

H04W72/0453H04J4/00H04L5/0007H04L25/02H04L27/0008H04L27/0014H04L27/1563H04L27/26H04W72/0446H04B7/2615H04L27/38

Abstract

Claims (65)

1. A decoding method for decoding a modulated signal, the method comprising:

determining a format of the modulated signal, wherein the format comprises either:

a first format comprising a first type of modulated signal; or

a second format comprising the first type of modulated signal and a second type of modulated signal that is different than the first type of modulated signal; and

decoding the modulated signal, comprising:

determining a frequency shift amount based on the format of the modulated signal;

shifting a frequency band of the first type of modulated signal or frequency bands of the first type of modulated signal and the second type of modulated signal from an original position to a shifted position, thereby shifting a center frequency of the first type of modulated signal by the frequency shift amount; and

filtering, based on the first or second format of the modulated signal, signals outside of the frequency band of the shifted first type of modulated signal.

2. The decoding method of claim 1 , wherein filtering comprises:

determining a set of filtering coefficients for the modulated signal based on whether the modulated signal comprises the first format or the second format; and

filtering the modulated signal using the set of filtering coefficients.

3. The decoding method of claim 1 , further comprising:

transforming the shifted first type of modulated signal from a frequency domain;

equalizing the transformed first type of modulated signal to generate an equalized signal; and

moving the equalized signal back to the original position.

4. The decoding method of claim 1 , wherein:

the first type of modulated signal comprises an Orthogonal Frequency-Division Multiple Access (OFDMA) signal; and

the second type of modulated signal comprises an Advanced Time Division Multiple Access (ATDMA) signal.

5. The decoding method of claim 1 , wherein determining whether the modulated signal comprises the first format or the second format comprises:

receiving scheduling information; and

determining, using the scheduling information, whether the modulated signal comprises the first format or the second format.

6. The decoding method of claim 1 , wherein the modulated signal is received on a frame-by-frame basis, and decoding the modulated signal comprises:

determining, for each frame, whether the frame comprises the first format or the second format; and

decoding each frame based on the determination, thereby allowing each frame dynamically change between the first format and the second format.

7. The decoding method of claim 1 , wherein:

determining the format comprises determining the format is the first format, wherein the first type of modulated signal comprises a wide bandwidth compared to a narrower bandwidth that the first type of modulated signal occupies for the second format;

determining the frequency shift amount comprises determining a frequency shift for the wide bandwidth; and

filtering comprises filtering signals outside of a wide frequency band of the shifted first type of modulated signal.

8. The decoding method of claim 1 , wherein:

determining the format comprises determining the format is the second format, wherein the first type of modulated signal comprises a narrow bandwidth compared to a wider bandwidth that the first type of modulated signal occupies for the first format;

determining the frequency shift amount comprises determining a frequency shift for the narrow bandwidth; and

filtering comprises filtering signals outside of a narrow frequency band of the shifted first type of modulated signal.

9. An apparatus for decoding a modulated signal, the apparatus comprising:

a decoder comprising a mixer and a filter, wherein the decoder is configured to:

determine a format of the modulated signal, wherein the format comprises either:

a first format comprising a first type of modulated signal; or

a second format comprising the first type of modulated signal and a second type of modulated signal that is different than the first type of modulated signal; and

decode the modulated signal, comprising:

determining a frequency shift amount based on the format of the modulated signal;

shifting, using the mixer, a frequency band of the first type of modulated signal or frequency bands of the first type of modulated signal and the second type of modulated signal from an original position to a shifted position, thereby shifting a center frequency of the first type of modulated signal by the frequency shift amount; and

filtering, using the filter, which takes into account the first or second format of the modulated signal, signals outside of the frequency band of the shifted first type of modulated signal.

10. The apparatus of claim 9 , wherein the decoder is configured to perform the filtering by:

determining a set of filtering coefficients for the modulated signal based on whether the modulated signal comprises the first format or the second format; and

filtering, using the filter, the modulated signal using the set of filtering coefficients.

11. The apparatus of claim 9 , wherein the decoder further comprises:

a fast Fourier transform (FFT) module configured to transform the shifted first type of modulated signal from a frequency domain;

an equalizer in communication with the FFT module, configured to equalize the transformed first type of modulated signal to generate an equalized signal; and

a shift register in communication with the equalizer, configured to move shift the equalized signal back to the original position.

12. The apparatus of claim 9 , wherein:

the first type of modulated signal comprises an Orthogonal Frequency-Division Multiple Access (OFDMA) signal; and

the second type of modulated signal comprises an Advanced Time Division Multiple Access (ATDMA) signal.

13. The apparatus of claim 9 , wherein the decoder is configured to determine whether the modulated signal comprises the first format or the second format by:

receiving scheduling information; and

determining, using the scheduling information, whether the modulated signal comprises the first format or the second format.

14. The apparatus of claim 9 , wherein the decoder is configured to:

decode the modulated signal by determining, for each frame of the modulated signal, whether the frame comprises the first format or the second format; and

decode each frame based on the determination, thereby allowing each frame dynamically change between the first format and the second format.

15. The apparatus of claim 9 , wherein:

determining the format comprises determining the format is the first format, wherein the first type of modulated signal comprises a wide bandwidth compared to a narrower bandwidth that the first type of modulated signal occupies for the second format;

determining the frequency shift amount comprises determining a frequency shift for the wide bandwidth; and

filtering comprises filtering signals outside of a wide frequency band of the shifted first type of modulated signal.

16. The apparatus of claim 9 , wherein:

determining the format comprises determining the format is the second format, wherein the first type of modulated signal comprises a narrow bandwidth compared to a wider bandwidth that the first type of modulated signal occupies for the first format;

determining the frequency shift amount comprises determining a frequency shift for the narrow bandwidth; and

filtering comprises filtering signals outside of a narrow frequency band of the shifted first type of modulated signal.

Assignments (8)

Continuity (2)