US 2013/0155833 A1 · APPARATUS AND METHOD FOR I/Q OFFSET CANCELLATION IN SC-FDMA SYSTEM

Abstract

The present invention relates to an apparatus and a method for eliminating I/Q offset in a receiver of a SC-FDMA system which improves performance of the system by accurate measurement and cancellation of I/Q offset in a receiver of a SC-FDMA system operating in a 3GPP LTE uplink. An apparatus for eliminating I/Q offset in a receiver of the SC-FDMA system constituting the receiver of the SC-FDMA system includes: a linear interpolation channel estimation unit for estimating channel using demodulation reference symbol (DMRS) that is a training sequence (X) corresponding to the discrete Fourier transformed signal (Y) that has passed through frame sync acquisition, frequency compensation and cyclic prefix elimination; a signal regeneration/cancellation unit for calculating I/Q offset (D=Y−Y′) by subtracting the discrete Fourier transformed signal (Y) from the ideal discrete Fourier transformed signal (Y′=H′X) generated by using channel coefficient (H′), that is an output of the linear interpolation channel estimation unit, and the DMRS that is the training sequence (X); and an I/Q offset measurement/cancellation unit for generating VQ offset-free signal (YNoDC=Y−D′) by subtracting I/Q offset (D′) having corrected phase and power of the VQ offset (D=Y−Y′) from the discrete Fourier transformed signal (Y).

Claims18

Dependent claims

An apparatus constituting a receiver for eliminating I/Q offset in the receiver of a SC-FDMA system comprising:

a linear interpolation channel estimation unit estimating channel using DMRS that is a training sequence (X) corresponding to the discrete Fourier transformed signal (Y) that has passed through frame sync acquisition, frequency compensation and cyclic prefix elimination;
a signal regeneration/cancellation unit calculating I/Q offset (D=Y−Y′) by subtracting the discrete Fourier transformed signal (Y) from the ideal discrete Fourier transformed signal (Y′=H′X) created by using the channel coefficient (H′), that is an output of the linear interpolation channel estimation unit, and the DMRS that is the training sequence (X);
and
an I/Q offset measurement/cancellation unit generating I/Q offset-free signal (YNoDC=Y−D′) by subtracting I/Q offset (D′) having corrected phase and power of the I/Q offset (D=Y−Y′) from the discrete Fourier transformed signal (Y).

1 more element

A method for eliminating I/Q offset in a receiver of a SC-FDMA system comprising the steps of:

(a) performing discrete Fourier transform of a signal that has been passed through frame sync acquisition, frequency correction, and cyclic prefix elimination;
(b) estimating channel coefficient (H′) of the discrete Fourier transformed signal (Y) using the DMRS that is the training sequence (X);
(c) obtaining an I/Q offset (D=Y−Y′) by subtracting the ideal discrete Fourier transformed signal (Y′=H′X) from the discrete Fourier transformed signal (Y), wherein the ideal discrete Fourier transformed signal (Y′=H′X) is generated using the channel coefficient (H′) that is estimated in step (b), and the DMRS that is the training sequence (X);
(d) generating an I/Q offset (D′) having corrected phase and power of the I/Q offset (D);
and
(e) generating a signal (YNoDC=Y−D′) whose I/Q offset is eliminated by subtracting the I/Q offset (D′) having corrected phase and power, from the discrete Fourier transformed signal (Y).

3 more elements

Dependencies are inferred from the claim text.

Apparatus and method for i/q offset cancellation in sc-fdma system

Life of this patent

Apparatus and method for i/q offset cancellation in sc-fdma system

Life of this patent

Abstract

Claims18