Receiver, transmitter and a method for digital multiple sub-band processing

Patent metadata

Field	Value
Publication number	US-9503284-B2
Application number	US-201214123229-A
Country	US
Kind code	B2
Filing date	Jun 10, 2012
Priority date	Jun 10, 2011
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

Highly efficient digital domain sub-band based receivers and transmitters.

First claim

We claim:

1. A receiver that comprises:
a set of first filters that share a common input;
a set of first downsamplers;
a set of sub-band processors, the set of sub-band processors comprises a set of decimators each of which comprises a second filter, a frequency-shifter and a second downsampler; wherein input signals provided to the decimators are frequency shifted from each other;
wherein the set of first downsamplers is coupled between the set of first filters and the set of sub-band processors;
wherein the set of first filters is arranged to receive digital input signal via the common input and to output virtual sub-channels of information occupying disjoint spectral sub-bands; wherein each sub-band is associated with a first filter and a second filter, wherein the first filter has a milder frequency response outside the sub-band than a frequency response of the second filter outside the sub-band;
wherein each first downsampler performs an L-factor downsampling, and wherein each decimator performs a V-factor downsampling; wherein L and V are positive rational numbers;
wherein each decimator comprises:
a serial to parallel conversion and a cyclic prefix drop module;
a V*N point fast Fourier transform (FFT) module arranged to output V*N element vectors;
an N point inverse FFT (IFFT) module;
a parallel to serial converter coupled to an output of the N point IFFT module; and
a circular shift module and sub-band extraction coupled between the V*N point FFT module and the N point IFFT module, the sub-band extraction and circular shift module is arranged to perform a circular shift operation on the V*N element output vectors to provide V*N element rotated vectors and to perform a sub-band extraction operation by extracting N elements from each V*N elements rotated vector, the N elements from each V*N elements rotated vector correspond to a single sub-band.

2. The receiver according to claim 1 , wherein each second filter substantially nullifies spectral components outside a sub-band associated with the second filter; wherein each first filter passes spectral components that belong to at least one sub-band that differs from a sub-band associated with the first filter.

3. The receiver according to claim 1 , wherein the sub-band extraction and circular shift module is a routing fabric arranged to implement the circular shift operation and the sub-band extraction operation by performing a mapping between outputs of the V*N point FFT module and inputs of the N point IFFT module.

4. The receiver according to claim 3 , wherein the sub-band extraction and circular shift module implements for the i-th sub-band processor implements a circular shift by [(−i modulo V)N]*modulo (VN) points followed by a mapping of N/2 top points of the VN-point FFT output and the N/2 bottom points of the VN-point FFT output onto the N points of the N-point IFFT input.

5. The receiver according to claim 4 wherein V=2.

6. The receiver according to claim 4 wherein V=4.

7. The receiver according to claim 4 wherein V=4/3.

8. The receiver according to claim 3 , wherein the routing fabric is arranged to implement the circular shift operation and the sub-band extraction operation without storing any elements of the V*N element output vectors within a buffer and without performing data transfers between different locations of the buffer.

9. The receiver according to claim 3 , wherein the routing fabric is arranged to couple between some groups of outputs of the V*N point FFT module and some groups of inputs of the N point IFFT module.

10. A receiver that comprises:
a set of first filters that share a common input;
a set of first downsamplers;
a set of sub-band processors, the set of sub-band processors comprises a set of decimators each of which comprises a second filter, a frequency-shifter and a second downsampler; wherein input signals provided to the decimators are frequency shifted from each other;
wherein the set of first downsamplers is coupled between the set of first filters and the set of sub-band processors;
wherein the set of first filters is arranged to receive digital input signal via the common input and to output virtual sub-channels of information occupying disjoint spectral sub-bands; wherein each sub-band is associated with a first filter and a second filter, wherein the first filter has a milder frequency response outside the sub-band than a frequency response of the second filter outside the sub-band;
wherein each first downsampler performs an L-factor downsampling, and wherein each decimator performs a V-factor downsampling; wherein L and V are positive rational numbers;
wherein each virtual sub-channel of information that occupies a sub-band is an Orthogonal Frequency Division Modulation (OFDM) compliant sub-channel of information; wherein each decimator is coupled to an OFDM receiver module; wherein a combination of each decimator and OFDM receiver module forms a sub-band processor comprising:
a serial to parallel conversion and a cyclic prefix drop module;
a V*N point fast Fourier transform (FFT) module arranged to output V*N element vectors;
a parallel to serial converter; and
a sub-band extraction and circular shift module coupled between the V*N point FFT module and the parallel to serial converter, that is arranged to perform a circular shift operation on the V*N element output vectors to provide V*N element circled vectors and to perform a sub-band extraction operation by extracting N elements from each V*N elements circled vector, the N elements corresponding to a single sub-band.

11. The receiver according to claim 10 , wherein L and V differ from a number (M) of sub-bands.

12. The receiver according to claim 10 , wherein a product of L and V equals to the number of sub-bands, M.

13. The receiver according to claim 10 , wherein V equals 4/3.

14. The receiver according to claim 10 , wherein V equals 2.

15. The receiver according to claim 10 , wherein V equals 4.

Assignees

• Nazarathy Moshe
• Tolmachev Alex
• Technion Res & Dev Foundation

Inventors

• Nazarathy Moshe
• Tolmachev Alex

Classifications

• H04L27/2665

  Fine synchronisation, e.g. by positioning the FFT window · CPC title

• H04L25/03891 Primary

  Spatial equalizers (MIMO diversity systems H04B7/0413) · CPC title

• H04L27/2644

  with oversampling · CPC title

• H04B7/0413

  MIMO systems · CPC title

• H04B17/364

  Delay profiles · CPC title