Radio receiver with hybrid channelizer architecture

• US 10,230,407 B2
• Filed: 07/14/2016
• Issued: 03/12/2019
• Est. Priority Date: 07/14/2016
• Status: Active Grant

• Current Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Original Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Inventors: Zhang, Hanhui
• Primary Examiner(s): Renner, Brandon M
• Assistant Examiner(s): Vogel, Jay L
• Application Number:
  US15/210,233
• Publication Number:
  US 20180019831A1
• Time in Patent Office: 971 Days
• CPC Class Codes: H04B 1/001 Channel filtering, i.e. selecting a frequency channel within the SDR system multiplexing of multicarrier modulation signals being represented by different frequencies H04L5/06; multiplexing of multicarrier modulation signals H04L5/023
• CPC Class Codes: H04L 5/0005 Time-frequency

Abstract

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a radio receiver with a hybrid channelizer architecture. In some implementations, a receiver includes an input to receive a first signal encoding digital samples of a radiofrequency signal. The receiver includes a frequency shifter configured to generate a second signal that is frequency shifted relative to the first signal. The receiver includes a first polyphase filter bank configured to receive the first signal and provide filter bank outputs for first sub-bands. The receiver includes a second polyphase filter bank configured to receive the second signal and provide filter bank outputs for second sub-bands. The receiver includes a switch network configured to select among the filter bank outputs and provide the filter bank outputs to respective digital channelizer modules for multiple channels.

Claims

1. A radio receiver comprising:

an input to receive a first signal encoding digital samples of a radiofrequency signal;

a frequency shifter configured to generate a second signal that is frequency shifted relative to the first signal;

a first polyphase filter bank configured to receive the first signal and provide filter bank outputs for a first plurality of sub-bands, each of the first plurality of sub-bands having a passband;

a second polyphase filter bank configured to receive the second signal and provide filter bank outputs for a second plurality of sub-bands, wherein each of the second plurality of sub-bands has a passband that at least partially overlaps with at least one of the passbands of the first plurality of sub-bands;

a switch network configured to (i) select, for each channel of multiple channels, a filter bank output for a respective sub-band from among the first plurality of sub-bands and the second plurality of sub-bands, and (ii) provide the filter bank outputs for the respective sub-bands to respective digital channelizer modules for the multiple channels, wherein the switch network is operable to vary which sub-bands are selected for the multiple channels;

control logic configured to (i) receive data indicating a channel center frequency for a particular channel of the multiple channels, (ii) select, from among the first plurality of sub-bands and the second plurality of sub-bands, a particular sub-band that has a sub-band center frequency that is closest to the channel center frequency for the particular channel, and (iii) determine a frequency difference between the channel center frequency for the particular channel and the sub-band center frequency for the particular sub-band; and

a signal generator configured to generate a mixing signal based on the frequency difference and provide the mixing signal to the digital channelizer module for the particular channel.

2. The radio receiver of claim 1, further comprising the digital channelizer modules, each channelizer module comprising a mixer, a low-pass filter, and a decimator, each of the channelizer modules providing baseband output for a different channel of the multiple channels.

3. The radio receiver of claim 1, wherein the first polyphase filter bank divides the first signal into a first plurality of equally-spaced sub-bands, and

wherein the second polyphase filter bank divides the second signal into a second plurality of equally-spaced sub-bands.

4. The radio receiver of claim 3, wherein the sub-bands in the first plurality of sub-bands and the second plurality of sub-bands each have an equal bandwidth.

5. The radio receiver of claim 1, wherein the radio receiver is configured to simultaneously decode signals from each of the multiple channels.

6. The radio receiver of claim 1, wherein the first sub-bands each have an equal bandwidth, and the frequency shifter includes a mixer configured to generate the second signal by mixing the first signal with a mixing signal having a frequency that is one half of a bandwidth of the first sub-bands.

7. The radio receiver of claim 1, wherein the radio receiver includes at least four polyphase filter banks having sub-bands with equal bandwidth, and the radio receiver configured to provide input signals with equally-spaced frequency offsets to each of the at least four polyphase filter banks.

8. The radio receiver of claim 1, wherein the switch network is operable to concurrently provide a filter bank output, from among the filter bank outputs of the first plurality of sub-bands and the second plurality of sub-bands, to digital channelizer modules for different channels of the multiple channels.

9. The radio receiver of claim 1, wherein the control logic is configured to change which filter bank output is selected for a first channel of the multiple channels in response to a change in the assigned carrier frequency of the first channel.

10. The radio receiver of claim 1, wherein the sub-bands each have a passband that is at least twice the bandwidth of the channels in the multiple channels.

11. A method comprising:

obtaining, from a radiofrequency signal received at a receiver, a first digital signal and second digital signal that is frequency shifted with respect to the first digital signal;

providing the first digital signal to a first polyphase filter bank that provides filter bank outputs for a first plurality of sub-bands, each of the sub-bands in the first plurality of sub-bands having a passband;

providing the second digital signal to a second polyphase filter bank that provides filter bank outputs for a second plurality of sub-bands, wherein each of the sub-bands in the second plurality of sub-bands has a passband that at least partially overlaps with at least one of the passbands of the first sub-bands; and

selecting, for each of multiple channels of output by the receiver, a respective sub-band from among the first plurality of sub-bands and the second plurality of sub-bands using switch logic operable to vary which sub-bands are selected for the multiple channels, wherein the selecting comprises;

determining a channel center frequency for a particular channel of the multiple channels; and

selecting, for the particular channel from among the first plurality of sub-bands and the second plurality of sub-bands, a particular sub-band that has a sub-band center frequency that is closest to the channel center frequency for the particular channel;

determining a frequency difference between the channel center frequency for the particular channel and the sub-band center frequency for the particular sub-band;

generating, a mixing signal based on the frequency difference; and

providing, the mixing signal and the filter bank output for the particular sub-band to a channelizer module for the particular channel.

12. The method of claim 11, further comprising generating a baseband output for each of the multiple channels using a plurality of digital channelizer modules, each digital channelizer module comprising a mixer, a low-pass filter, and a decimator.

13. The method of claim 11, further comprising:

dividing the first signal into a first plurality of equally-spaced sub-bands using the first polyphase filter bank; and

dividing the second signal into a second plurality of equally-spaced sub-bands using the second polyphase filter bank.

14. The method of claim 13, wherein the sub-bands in the first plurality of sub-bands and the second plurality of sub-bands each have an equal bandwidth.

15. The method of claim 11, further comprising simultaneously decoding, by the receiver, signals from each of the multiple channels.

16. The method of claim 11, wherein the sub-bands in the first plurality of sub-bands each have an equal bandwidth, and wherein the method further comprises:

generating the second signal by mixing the first signal with a mixing signal having a frequency that is one half of a bandwidth of the first sub-bands.

17. The method of claim 11, wherein the selecting comprises selecting a same filter bank output, from among the first plurality of sub-bands and the second plurality of sub-bands, for at least two of the multiple channels.

18. One or more non-transitory machine-readable storage media storing instructions that when executed by one or more processors cause the one or more processors to perform operations comprising:

obtaining, from a radiofrequency signal received at a receiver, a first digital signal and second digital signal that is frequency shifted with respect to the first digital signal;

providing the first digital signal to a first polyphase filter bank that provides filter bank outputs for a first plurality of sub-bands, each of the sub-bands in the first plurality of sub-bands having a passband;

providing the second digital signal to a second polyphase filter bank that provides filter bank outputs for a second plurality of sub-bands, wherein each of the sub-bands in the second plurality of sub-bands has a passband that at least partially overlaps with at least one of the passbands of the first sub-bands;

selecting, for each of multiple channels of output by the receiver, a respective sub-band from among the first plurality of sub-bands and the second plurality of sub-bands using switch logic operable to vary which sub-bands are selected for the multiple channels, wherein the selecting comprises;

determining a channel center frequency for a particular channel of the multiple channels; and

selecting, for the particular channel from among the first plurality of sub-bands and the second plurality of sub-bands, a particular sub-band that has a sub-band center frequency that is closest to the channel center frequency for the particular channel;

determining a frequency difference between the channel center frequency for the particular channel and the sub-band center frequency for the particular sub-band;

generating, a mixing signal based on the frequency difference; and

providing, the mixing signal and the filter bank output for the particular sub-band to a channelizer module for the particular channel.