Baseband processing of TDD signals

Patent metadata

Field	Value
Publication number	US-9699013-B2
Application number	US-201214411528-A
Country	US
Kind code	B2
Filing date	Jun 29, 2012
Priority date	Jun 29, 2012
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

Transceiver device and method therein, for baseband processing of signals associated with TDD communication over wire lines. The method involves use of a single burst I/O N-point complex FFT kernel for baseband processing of receive and transmit signal blocks, where the processing involves simultaneously performing a respective FFT or IFFT of two N-sample signal blocks.

First claim

The invention claimed is:

1. A method, in a transceiver, for baseband processing of signals associated with Time Division Duplexing (TDD) multicarrier communication over one or more wire lines, the method comprising:
combining two signal blocks, A and B, each comprising N samples, into a signal X comprising N complex points, wherein each of the two blocks is either a real-valued N-sample time-domain receive signal block rn, or a complex Hermitian-symmetric N-sample frequency-domain transmit signal block T k ;
performing a complex FFT on the signal X using a single, burst-I/O, N point, complex FFT kernel, thus providing a signal X′ CFFT comprising N complex points; and
deriving an N-point discrete Fourier transform or N-point inverse discrete Fourier transform, A′ and B′, for the signal blocks A and B, from the signal X′ CFFT .

2. The method of claim 1 , wherein the combining comprises:
when A and B are time-domain receive blocks r 1 and r 2 :
arranging r 1 as the real part of the signal X, and r 2 as imaginary part of the signal X;

when A and B are frequency-domain transmit blocks T 1 and T 2 :
computing the real part of the signal X as the sum of the real part of the Hermitian symmetric extension of T 1 and the imaginary part of the Hermitian symmetric extension of T 2 , and
computing the imaginary part of the signal X as the difference of the real part of the Hermitian symmetric extension of T 2 and the imaginary part of the Hermitian symmetric extension of T 1 ; and,

when one of A and B is a time-domain receive block, r, and the other a frequency-domain transmit block T, one of the following four alternatives:
i) arranging r as the real part of the signal X and computing the imaginary part of the signal X as the difference of the real part and imaginary part of the Hermitian symmetric extension of T;
ii) computing the real part of the signal X as the sum of the real part of the Hermitian symmetric extension of T and the odd part of r, and computing the imaginary part of the signal X as the difference of the even part of r and the imaginary part of the Hermitian symmetric extension of T;
iii) computing the real part of the signal X as the sum of the imaginary part of the Hermitian symmetric extension of T and the even part of r, and computing the imaginary part of the signal X as the difference of the real part of the Hermitian symmetric extension of T and the odd part of r;
iv) computing the real part of the signal X as the difference of the real part and imaginary part of the Hermitian symmetric extension of T, and arranging r as the imaginary part of the signal X.

3. The method of claim 1 , wherein the deriving comprises:
when A and B are time-domain receive blocks r 1 and r 2 having Fourier transforms R 1 and R 2 :
deriving real and imaginary part of R 1 as even and odd part of real and imaginary part of the signal X′ CFFT , respectively, and
deriving real and imaginary part of R 2 as even and negative odd part of imaginary and real part of the signal X′ CFFT , respectively;

when A and B are frequency-domain transmit blocks T 1 and T 2 having inverse Fourier transforms t 1 and t 2 :
deriving t 1 as the real part of the signal X′ CFFT multiplied by a scaling factor c IFFT , and
deriving t 2 as the imaginary part of the signal X′ CFFT multiplied the scaling factor c IFFT ;

when one of A and B is a time-domain receive block, r having a Fourier transform R, and the other is a frequency-domain transmit block T, having an inverse Fourier transform t, one of the following four alternatives:
i) computing real and imaginary part of R as even and odd part of real and imaginary part of the signal X′ CFFT , respectively, and
computing t as sum of even part of the imaginary part of X′ CFFT and odd part of real part of X′ CFFT followed by multiplication with the scaling factor c IFFT ;
ii) computing real and imaginary part of R as even and odd part of the imaginary part of the signal X′ CFFT , respectively, and
deriving t as the real part of X′ CFFT multiplied with the scaling factor c IFFT ;
iii) computing real and imaginary part of R as even and odd part of the real part of the signal X′ CFFT , respectively, and
deriving t as the imaginary part of X′ CFFT multiplied with the scaling factor c IFFT ;
iv) computing real and imaginary part of R as even and negative odd part of imaginary and real part of the signal X′ CFFT , respectively, and
computing t as difference of the even part of the real part of X′ CFFT and odd part of imaginary part of X′ CFFT followed by multiplication with the scaling factor c IFFT .

4. The method of claim 1 , wherein the deriving comprises:
when A and B are time-domain receive blocks r 1 and r 2 having Fourier transforms R 1 and R 2 :
deriving real and imaginary part of R 1 as even and odd part of real and imaginary part of the signal X′ CFFT , respectively, and
deriving real and imaginary part of R 2 as even and negative odd part of imaginary and real part of the signal X′ CFFT , respectively;

when A and B are frequency-domain transmit blocks T 1 and T 2 having inverse Fourier transforms t 1 and t 2 :
deriving t 1 as the real part of the signal X′ CFFT , and
deriving t 2 as the imaginary part of the signal X′ CFFT ;

when one of A and B is a time-domain receive block, r having a Fourier transform R, and the other is a frequency-domain transmit block T, having an inverse Fourier transform t, one of the following four alternatives:
i) computing real and imaginary part of R as even and odd part of real and imaginary part of the signal X′ CFFT , respectively, and
computing t as sum of even part of the imaginary part of X′ CFFT and odd part of real part of X′ CFFT ;
ii) computing real and imaginary part of R as even and odd part of the imaginary part of the signal X′ CFFT , respectively, and
deriving t as the real part of X′ CFFT ;
iii) computing real and imaginary part of R as even and odd part of the real part of the signal X′ CFFT , respectively, and
deriving t as the imaginary part of X′ CFFT ;
iv) computing real and imaginary part of R as even and negative odd part of imaginary and real part of the signal X′ CFFT , respectively, and
computing t as difference of the even part of the real part of X′ CFFT and odd part of imaginary part of X′ CFFT .

5. The method of claim 1 , wherein the TDD multicarrier communication is performed over one or more wire lines of metal.

6. The method of claim 1 , wherein the method is performed in a communication system operating according to communication standard G.fast.

7. A transceiver for baseband processing of signals associated with Time Division Duplexing (TDD) multicarrier communication over one or more wire lines, the transceiver comprising:
a combining circuit, adapted to combine two signal blocks, A and B, each comprising N samples, into a signal X comprising N complex points, wherein each of the two blocks A and B is either a real-valued N-sample time-domain receive signal block r n , or a complex Hermitian-symmetric N-sample frequency-domain transmit signal block T k ;
a burst-I/O, N-point, complex FFT kernel, adapted to perform a complex FFT on the signal X, thus providing a signal X′ CFFT comprising N complex points; and
a deriving circuit, adapted to derive an N-point discrete Fourier transform or N-point inverse discrete Fourier transform, A′ and B′, for the signal blocks A and B, from the signal X′ CFFT .

8. The transceiver of claim 7 , wherein the combining circuit is adapted to combine the two signal blocks by:
when A and B are time-domain receive blocks r 1 and r 2 :
arranging r 1 as the real part of the signal X, and r 2 as imaginary part of the signal X;

when A and B are fre

Assignees

• Trojer Elmar
• Magesacher Thomas
• Ericsson Telefon Ab L M

Inventors

• Trojer Elmar
• Magesacher Thomas

Classifications

• H04L27/263 Primary

  modification of IFFT/IDFT modulator for performance improvement · CPC title

• H04L5/023

  Multiplexing of multicarrier modulation signals, e.g. multi-user orthogonal frequency division multiple access [OFDMA] (multicarrier modulation H04L27/2601) · CPC title

• H04J4/00

  Combined time-division and frequency-division multiplex systems (H04J13/00 takes precedence {; data transmission H04L5/26; telemetry G08C15/00}) · CPC title

• H04L27/2651

  Modification of fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators for performance improvement · CPC title