SYNCHRONIZATION SYSTEM AND METHOD FOR TRANSMISSION AND RECEPTION IN AUDIBLE FREQUENCY RANGE-BASED SOUND COMMUNICATION, AND APPARATUS APPLIED THERETO

• US 20120269371A1
• Filed: 06/18/2012
• Published: 10/25/2012
• Est. Priority Date: 12/17/2009
• Status: Active Grant

• Current Assignee: Seoul National University R&DB Foundation (Seoul National University), SK Telecom Co., Ltd.
• Original Assignee: Seoul National University R&DB Foundation (Seoul National University), SK Telecom Co., Ltd.
• Inventors: KIM, Dong Keon, KIM, Moon Kee, CHOI, Keun Hwan, YU, Jae Hwang, KIM, Min Seok, KIM, Nam Soo, YUN, Hwan Sik, CHO, Ki Ho
• Granted Patent: US 8,897,474 B2
• Time in Patent Office: Days
• US Class Current: 381/337
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal

Abstract

Provided is a synchronization system and method for acoustic communication in audible frequency range, and an apparatus applied thereto. The synchronization system for acoustic communication in audible frequency range is configured to prevent deterioration of a synchronization performance and to reduce an amount of calculation by calculating a correlation based on a few samples as opposed to calculating a correlation for each sample when a receiver of the acoustic communication performs synchronization while the acoustic communication is performed in the audible frequency range through modification of an audio signal or adding of a predetermined signal to an audio signal.

Claims

1. A receiving apparatus for acoustic data communication in audible frequency range, the apparatus comprising:

a transforming unit configured to receive an audio signal, the audio signal being formed by inserting synchronization data into a frequency-domain signal transformed based on a first-type transform and being inverse-transformed, based on the first-type transform, into a time-domain signal, and to transform the audio signal into a frequency-domain signal based on a second-type transform;

a normalizing unit configured to normalize a size of coefficient of the frequency-domain signal transformed based on the second-type transform to a predetermined size;

an inner product calculating unit configured to calculate an inner product of the normalized signal and a pre-generated synchronization signal;

an inverse-transforming unit configured to inverse-transform, based on the second-type transform, a result of the inner product;

a correlation unit configured to generate a correlation value by overlapping the inverse-transformed signal with a previous inversed transformed signal in a predetermined interval; and

a synchronization point detecting unit configured to determine a point of the synchronization data based on a point of a peak in the correlation value.

2. The apparatus as claimed in claim 1, wherein the first transform or the inverse-transform based on the first-type transform includes a modified complex lapped transform (MCLT),

wherein the second-type transform or the inverse-transform based on the second-type transform includes a fast Fourier transform (FFT), and

wherein the transforming unit is configured to transform an input signal which is consist of a frame of audio signal and a predetermined vector.

3. The apparatus as claimed in claim 2, wherein, after transforming the input signal, the transforming unit configured to use, as an input signal, a audio signal corresponding to a length of the vector.

4. The apparatus as claimed in claim 1, further comprising:

a synchronization signal generating unit configured to generate the synchronization signal.

5. The apparatus as claimed in claim 4, wherein the synchronization signal generating unit comprises:

a first processing module configured to generate the synchronization data to be a first-type signal;

a second processing module configured to inverse-transform the first-type signal into a time-domain signal, and to overlap the inverse-transformed first type signal with adjacent inversed transformed signals to the inverse-transformed first type signal in a predetermined interval; and

a third processing module configured to generate an input signal by adding a predetermined vector to a result obtained from the second processing module, to transform the input signal into a frequency-domain signal based on the second-type transform, and to provide the transformed input signal to the inner product calculating unit.

6. A synchronization method for acoustic data communication in audible frequency range, the method comprising:

receiving an audio signal, the audio signal being formed by inserting synchronization data into a frequency-domain signal transformed based on a first-type transform and being inverse-transformed, based on the first-type transform, into a time-domain signal, and transforming the audio signal into a frequency-domain signal based on a second-type transform;

normalizing, to a predetermined size, a size of coefficient of the frequency-domain signal transformed based on the second-type transform;

calculating an inner product of the normalized signal and a pre-generated synchronization signal;

inverse-transforming, based on the second-type transform, a result of the inner product;

generating a correlation value by overlapping the inverse-transformed signal with a previous inversed transformed signal in a predetermined interval; and

determining a point of the synchronization data based on a peak value in the correlation value.

7. The method as claimed in claim 6, further comprising:

generating a synchronization signal.

8. The method as claimed in claim 7, wherein generating of the synchronization signal comprises:

a first processing to generate the synchronization data to be a first-type signal;

a second processing to inverse-transform the first-type signal into a time-domain signal, and to overlap the inverse-transformed first type signal with adjacent inversed transformed signals to the inverse-transformed first type signal in a predetermined interval; and

a third processing to generate an input signal by adding a predetermined vector to a result obtained from the second processing, to transform the input signal into a frequency-domain signal based on the second-type transform, and to provide the transformed input signal to the inner product calculating unit.