In-band adjacent-channel digital audio broadcasting system

• US 20020080887A1
• Filed: 09/28/2001
• Published: 06/27/2002
• Est. Priority Date: 10/20/2000
• Status: Active Grant

• Current Assignee: Uniloc 2017 LLC (SoftBank Group Corp.)
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Lee, Soo-in, Park, So-Ra, Kim, Geon, Jeong, Young-Ho
• Granted Patent: US 7,050,511 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 25/03866 using scrambling
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2614 Peak power aspects

Abstract

The in-band adjacent-channel digital audio broadcasting system includes a scrambling unit for scrambling a signal to be broadcasted, thereby generating a scrambled signal; an outer coding unit for performing a first encoding of the scrambled signal, thereby generating an outer encoded signal; an outer interleaving unit for performing a first interleaving of the outer encoded signal a byte by byte basis, thereby generating an outer interleaved signal; an inner coding unit for performing a second encoding the outer interleaved signal, thereby generating an inner encoded signal; an inner interleaving unit for performing a second interleaving of the inner encoded signal, thereby generating an inner interleaved signal; a modulating unit for modulating the inner interleaved signal, thereby generating an orthogonal frequency division multiplexing (OFDM) symbols; a guard interval inserting unit for inserting a guard interval between the OFDM symbols in order to eliminate an inter-symbol interference, thereby generating an OFDM frame; and an RF processing unit for performing a conversion of the OFDM frame into an analog radio frequency signal so that the OFDM signal can be transmitted in a specific frequency channel of an FM frequency band, and for amplifying and outputting the analog radio frequency signal.

Claims

1. An in-band adjacent-channel digital audio broadcasting system, comprising:

a scrambling unit for scrambling a signal to be broadcasted, thereby generating a scrambled signal;

an outer coding unit for performing a first encoding of the scrambled signal, thereby generating an outer encoded signal;

an outer interleaving unit for performing a first interleaving of the outer encoded signal a byte by byte basis, thereby generating an outer interleaved signal;

an inner coding unit for performing a second encoding the outer interleaved signal, thereby generating an inner encoded signal;

an inner interleaving unit for performing a second interleaving of the inner encoded signal, thereby generating an inner interleaved signal;

a modulating unit for modulating the inner interleaved signal, thereby generating an orthogonal frequency division multiplexing (OFDM) symbols;

a guard interval inserting unit for inserting a guard interval between the OFDM symbols in order to eliminate an inter-symbol interference, thereby generating an OFDM frame; and

an RF processing unit for performing a conversion of the OFDM frame into an analog radio frequency signal so that the OFDM signal can be transmitted in a specific frequency channel of an FM frequency band, and for amplifying and outputting the analog radio frequency signal.

2. The system as recited in claim 1, wherein said modulating unit includes:

a signal mapping unit for generating 8PSK or 16QAM data samples based on the inner interleaved signal;

a frame adapting unit for constructing a transmission frame based on TPSs, pilot samples and data samples; and

an IFFT unit for performing an inverse fast Fourier transform (IFFT) of the transmission frame to generate OFDM symbols.

3. The system as recited in claim 2, wherein the first encoding includes an RS coding.

4. The system as recited in claim 3, wherein the second encoding includes a convolutional coding.

5. The system as recited in claim 4, wherein the second encoding further includes a trellis coding.

6. The system as recited in claim 5, wherein said system concurrently supports both of coded-orthogonal frequency division multiplexing (COFDM) and Trellis COFDM (TCOFDM) transmission modes based on the same systematic parameters.

7. The system as recited claim 6, wherein a conversion of the COFDM and the TCOFDM transmission mode is efficiently embodied by a change of an output data rate of an MPEG-2 multiplexer.

8. The system as recited in claim 5, wherein said system has an occupation bandwidth of about 482 kHz for the sake of a transmission within the FM band, and maintains a maximum power spectral density (PSD) level of the analog radio frequency signal lower by more 25 dB than a peak PSD level of the analog radio frequency signal in frequency domain, and a number of sub-carriers of the OFDM symbol is 512.

9. The system as recited in claim 8, wherein the OFDM symbol is OFDM-modulated by using 2048 IFFT, to generate the intermediate frequency signal whose central frequency is about 1446 kHz.

10. The system as recited in claim 5, wherein said system includes a time interleaving structure capable of applying the same interleaving depth regardless of modulation (8PSK, 16QAM) and transmission types (COFDM, TCOFDM).

11. The system as recited in claim 5, wherein said system includes a frequency interleaving of a permutation basis that is capable of being applied to the number of useful sub-carriers of two kinds of OFDM symbols, 366 and 490.

12. The system as recited in claim 5, wherein the signal transmission frame is constructed by detailed units of an OFDM super-frame, an OFDM frame, an OFDM sub-frame and an OFDM symbol.

13. The system as recited in claim 12, wherein the OFDM super-frame includes four OFDM frames, the OFDM frame includes eight OFDM sub-frames, and the OFDM sub-frame includes four OFDM symbols.

14. The system as recited in claim 12, wherein a number of useful sub-carriers constructing the OFDM sub-frame is 1,836, a scattered pilot is inserted by the 128 number into one OFDM symbol in a pattern of 4×

4 samples in a time and frequency space, and a continual pilot and a TPS are inserted respectively by 15 and 7 for all the OFDM symbols, and at this time, the scattered pilot and the continual pilot in each transmission frame has four repeated insertion position.

15. The system as recited in claim 5, wherein the OFDM frame includes 32 OFDM symbols and a number of bits of TPS information is 32 in order to obtain a rapid synchronization of transmission frame.

16. The system as recited in claim 5, wherein a number of RS packets contained in each OFDM super-frame is 54 in case of 8PSK so that synchronization can be performed efficiently.

17. The system as recited in claim 5, wherein a number of RS packets contained in each OFDM super-frame is 72 in case of 16QAM so that synchronization can be performed efficiently.