System for digital information transmission with associated methods and devices

• US 6,442,211 B1
• Filed: 03/22/1999
• Issued: 08/27/2002
• Est. Priority Date: 09/20/1996
• Status: Expired due to Term

• Current Assignee: iAd Gesellschaft Automatisierung und Datenverarbeitungs GmbH
• Original Assignee: IAD Gesellschaft Fur Informatik Automatisierung und Datenverarbeitung mbH
• Inventors: Lehmann, Klaus, Wagner, Thomas, Hampel, Herrmann, Huber, Johannes
• Primary Examiner(s): Vo, Don N.
• Application Number:
  US09/275,643
• Time in Patent Office: 1,254 Days
• Field of Search: 375/260, 375/261, 375/262, 370/210
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 27/2602 Signal structure

Abstract

The system achieves high bandwidth efficiency and a low bit and message error probability in digital data transmission. The system, with its associated methods and devices, obviates carrier synchronization or clock synchronization. Digital multicarrier transmission with coding and decoding is carried out on the basis of block synchronization, wherein, for carrier modulation, the modulation of the subcarriers is carried out differentially in coded form in the direction of the subcarriers, that is to say in the frequency domain.

Claims

1. In a method of producing a transmission signal for digital information transmission, wherein, for multicarrier transmission, subcarriers are modulated with channel coded parallel code symbols of an input signal by means of differential coding in the frequency domain, and synchronization information is added to the transmission signal, the improvement which comprises:

prior to the differential coding, at least one of error coding and interleaving;

subsequent to the differential coding, producing a serial output signal by means of parallel/serial conversion;

assigning each block of code symbols, as synchronization information, a preamble for block synchronization; and

subsequent to the differential coding, adding to each block of code symbols a transmission pause.

2. The method according to claim 1, which further comprises subjecting the serial output signal to digital/analog conversion.

3. The method according to claim 1, wherein the serial output signal is transmitted in transmission blocks with one of time discontinuities and in burst mode.

4. The method according to claim 1, which comprises, after the differential coding, adding to each block of code symbols at a start thereof, a periodic continuation as a guard interval.

5. The method according to claim 1, which comprises, prior to the differential coding, assigning the code symbols to a signal space by means of a method selected from the group consisting of PSK and QAM.

6. The method according to claim 1, which comprises, after the differential coding, carrying out an inverse discrete Fourier transform.

7. A device for producing a transmission signal for digital information transmission with a multicarrier transmission method, comprising:

a module for carrier modulation receiving channel coded, parallel code symbols of an input signal and adding code symbols to subcarriers by means of differential coding in a frequency domain, wherein the transmission signal contains synchronization information;

a module for at least one of error coding and interleaving connected upstream of the module for carrier modulation in a signal flow direction;

a parallel/serial converter connected downstream of the module for carrier modulation in the signal flow direction;

a synchronization device for producing synchronization information, said synchronization device producing a preamble for each produced block of code symbols for block synchronization; and

an element for producing a transmission pause between successive blocks.

8. The device according to claim 7, which further comprises a digital/analog converter connected downstream of said parallel/serial converter in the signal flow direction.

9. The device according to claim 8, wherein said digital/analog converter has an output outputting an output signal in transmission blocks produced with at least one of time discontinuities and a burst mode.

10. The device according to claim 7, which further comprises a mapping module connected upstream of the module for carrier modulation in the signal flow direction, said mapping module assigning the code symbols to a signal space with a method selected from the group of methods consisting of PSK and QAM.

11. The device according to claim 7, which further comprises a channel coder connected upstream of said module for carrier modulation in the signal flow direction.

12. The device according to claim 7, wherein said module for carrier modulation comprises an element for inverse discrete Fourier transformation.

13. An improved demodulation method for a received multicarrier transmission signal, wherein code symbols are modulated onto subcarriers by means of differential coding in the frequency domain, and wherein blocks follow one another with time discontinuities, and a phase of complex subcarrier coefficients is distinguished and blocks of code symbols are synchronized, the improvement which comprises:

prior to differentiation, subjecting the received transmission signal to analog/digital conversion with subsequent serial/parallel conversion;

prior to differentiation, removing any transmission pause between adjacent blocks;

subsequent to differentiation, carrying out one of error decoding and deinterleaving; and

detecting respective preambles assigned to the blocks, and synchronizing each of the blocks.

14. The demodulation method according to claim 13, wherein the differentiation comprises carrying out a discrete Fourier transform.

15. The demodulation method according to claim 13, which comprises assigning an inverse signal space, and subsequently performing a step of channel decoding.

16. The demodulation method according to claim 15, which comprises following the channel decoding by parallel/serial conversion.

17. The demodulation method according to claim 13, which comprises phase synchronizing with the preamble.

18. The demodulation method according to claim 17, wherein the synchronizing step comprises detecting a periodic continuation in the preamble.

19. A receiving device for a received multicarrier transmission signal, wherein code symbols are modulated onto subcarriers by means of differential coding in a frequency domain, and wherein blocks follow one another with time discontinuities, comprising:

an analog/digital converter receiving a transmission signal;

a serial/parallel converter connected downstream of said analog/digital converter in a signal flow direction;

a demodulator for differentiating a phase of complex subcarrier coefficients and for synchronizing blocks connected downstream of said serial/parallel converter in the signal flow direction;

an error decoding and/or deinterleaving module connected downstream of said demodulator in the signal flow direction;

a downstream channel decoder connected downstream of said demodulator in the signal flow direction;

means for removing a transmission pause between the blocks; and

a synchronization device for detecting preambles assigned to the respective blocks of code symbols and for synchronizing with the preambles.

20. The receiving device according to claim 19, wherein said demodulator comprises an element for discrete Fourier transformation.

21. The receiving device according to claim 19, which further comprises a module for inverse mapping and for inverse signal space assignment.

22. The receiving device according to claim 21, which further comprises a parallel/serial converter connected downstream of said channel decoder in the signal flow direction.

23. A system for digital information transmission with a multicarrier transmission method, comprising:

a device for producing a transmission signal, said device having a module for carrier modulation receiving channel coded parallel code symbols of an input signal and adding to subcarriers thereof the code symbols by means of differential coding in a frequency domain, an error coding and/or interleaving module connected upstream of said module for carrier modulation in a signal flow direction, and a parallel/serial converter connected downstream of said module for carrier modulation in the signal flow direction;

means for producing synchronization information by producing a preamble for each produced block of code symbols for block synchronization, and an element for inserting a transmission pause between successive blocks;

a receiving device for the received multicarrier transmission signal in which the blocks follow one another, possibly with time discontinuities, said receiving device having a serial/parallel converter connected downstream of said parallel/serial converter in the signal flow direction, a demodulator for differentiating a phase of complex subcarrier coefficients connected downstream of said serial/parallel converter, an error decoding and/or deinterleaving module connected downstream of the demodulator, means for removing the transmission pause from between the blocks, means for detecting the preambles respectively assigned to respective blocks, and for synchronizing the respective blocks.

24. The system according to claim 23, which further comprises a digital/analog converter connected downstream of said parallel/serial converter, and an analog/digital converter connected upstream of said serial/parallel converter in said receiving device.

25. The system according to claim 23, wherein a wireless transmission path is defined through the system.

26. The system according to claim 25, wherein said wireless transmission path is a radio link.

27. The system according to claim 23, wherein an optical transmission path is defined through the system.

28. The system according to claim 27, wherein said optical transmission path is defined in an optical conductor.

29. The system according to claim 23, which comprises a transmission path defined through a link selected from the group consisting of a power cable, a non-power cable, and an equivalent network.

30. The system according to claim 29, wherein the transmission path is defined by a link equivalent to an EIB, or a power distribution network.