# US 2010/0166106 A1 · Discrete fourier transform processing apparatus and radio communication apparatus

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- Number: US 2010/0166106 A1
- Document ID: US20100166106A1
- Status: Published application
- Kind: A1
- Application number: 12/646,595
- Filed: 2009-12-23
- Published: 2010-07-01
- Earliest claimed: 2008-12-26
- Assignees: Fujitsu Limited
- Inventors: Jun KAMEYA
- Web page: https://patentgrep.com/patent/US20100166106A1

## CPC

- G06F 17/142: {Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm}
- H04L 27/2636: {with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

An arithmetic processing apparatus includes a shift section configured to shift, by (N+1)/2 bit data, a data signal x(n) (n=0, . . . , N−1), which has a data length of N, where N is an odd number, and which has left-right symmetry with respect to ((N−1)/2)th bit data, so as to obtain a data signal x′(n), and an arithmetic operation section configured to obtain a data signal X(k) (k=0, . . . , N−1) by performing a discrete Fourier transform operation on the data signal x′(n).

## Claims

### Claim 1

An arithmetic processing apparatus comprising:
a shift section configured to shift, by (N+1)/2 bit data, a data signal x(n) (n=0, . . . , N−1), which has a data length of N, where N is an odd number, and which has left-right symmetry with respect to ((N−1)/2)th bit data, so as to obtain a data signal x′(n); and
an arithmetic operation section configured to obtain a data signal X(k) (k=0, . . . , N−1) by performing a discrete Fourier transform operation on the data signal x′(n).

### Claim 2 (depends on 1)

The arithmetic processing apparatus according to claim 1,
wherein the arithmetic operation section performs the discrete Fourier transform operation by using twiddle factors based on a cosine function that includes a value k in an angle component.

### Claim 3 (depends on 2)

The arithmetic processing apparatus according to claim 2,
wherein the arithmetic operation section obtains a data signal X(k) (k=1, . . . , (N−1)/2) or a data signal X(N−k) (k=1, . . . , (N−1)/2) by the discrete Fourier transform operation.

### Claim 4 (depends on 3)

The arithmetic processing apparatus according to claim 3,
wherein, among the values of k at which absolute values of the cosine function do not become +1, the arithmetic operation section approximates, to +1 or −1, the values of the cosine function corresponding to a certain number of the values of k in order from the absolute value of the cosine function closest to +1.

### Claim 5

A radio communication apparatus configured to transmit a random access channel by using a data signal x(n) (n=0, . . . , n−1) which has a data length of N bits, where N is an odd number, and which has left-right symmetry with respect to ((N−1)/2)th bit data, the radio communication apparatus comprising:
a shift section configured to shift the data signal x(n) by (N+1)/2 bits, so as to obtain a data signal x′(n);
a discrete Fourier transform operation section configured to obtain a data signal X(k) (k=0, . . . , N−1) by performing a discrete Fourier transform operation on the data signal x′(n); and
a phase rotation operation section configured to perform an operation to rotate a phase of the data signal X(k).

### Claim 6 (depends on 5)

The radio communication apparatus according to claim 5, wherein the discrete Fourier transform operation section performs the discrete Fourier transform operation by using twiddle factors based on a cosine function that includes a value of k in an angle component.

### Claim 7 (depends on 6)

The radio communication apparatus according to claim 6, wherein the discrete Fourier transform operation section obtains a data signal X(k) (k=1, . . . , (N−1)/2) or a data signal X(N−k) (k=1, . . . , (N−1)/2) by the discrete Fourier transform operation.

### Claim 8 (depends on 7)

The radio communication apparatus according to claim 7,
wherein, among the values of k at which absolute values of the cosine function do not become +1, the discrete Fourier transform operation section approximates, to +1 or −1, the values of the cosine function corresponding to a certain number of the values of k in order from the absolute value of the cosine function closest to +1.

### Claim 9 (depends on 5)

The radio communication apparatus according to claim 5,
wherein the data signal x(n) (n=0, . . . , n−1) is a Zadoff-Chu sequence, and wherein the random access channel is a physical random access channel in a LTE (Long Term Evolution) system.