Communication system

• US 20040161049A1
• Filed: 02/17/2004
• Published: 08/19/2004
• Est. Priority Date: 03/26/1992
• Status: Abandoned Application

• Current Assignee: Mitsuaki Oshima
• Original Assignee: Mitsuaki Oshima
• Inventors: Oshima, Mitsuaki
• Application Number:
  US10/778,171
• Publication Number:
  US 20040161049A1
• Time in Patent Office: Days
• US Class Current: 375/265
• CPC Class Codes: H03M 13/23 using convolutional codes, e.g. unit memory codes
• CPC Class Codes: H03M 13/253 with concatenated codes
• CPC Class Codes: H03M 13/256 with trellis coding, e.g. with convolutional codes and TCM
• CPC Class Codes: H03M 13/2936 comprising an outer Reed-Solomon code and an inner convolutional code
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H03M 13/356 Unequal error protection [UEP]
• CPC Class Codes: H03M 13/6538 ATSC VBS systems
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0054 Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0058 Block-coded modulation
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/006 Trellis-coded modulation
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 2001/0098 Unequal error protection
• CPC Class Codes: H04L 2027/0036 using a recovered symbol clock
• CPC Class Codes: H04L 2027/0053 Closed loops
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 27/02 : Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation H04L27/32 takes precedence
• CPC Class Codes: H04L 27/04 : Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/183 : Multiresolution systems
• CPC Class Codes: H04L 27/2602 : Signal structure
• CPC Class Codes: H04L 27/2604 : Multiresolution systems by means of multiresolution subcarriers H04L27/183, H04L27/3488
• CPC Class Codes: H04L 27/2627 : Modulators
• CPC Class Codes: H04L 27/2649 : Demodulators
• CPC Class Codes: H04L 27/3405 : Modifications of the signal space to increase the efficiency of transmission, e.g. reduction of the bit error rate, bandwidth, or average power
• CPC Class Codes: H04L 27/3488 : Multiresolution systems
• CPC Class Codes: H04L 27/36 : Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/38 : Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/3854 : using a non - coherent carrier, including systems with baseband correction for phase or frequency offset
• CPC Class Codes: H04L 5/0007 : the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0046 : Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04N 11/26 : involving two-channel transmission
• CPC Class Codes: H04N 19/30 : using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/37 : with arrangements for assigning different transmission priorities to video input data or to video coded data
• CPC Class Codes: H04N 19/60 : using transform coding
• CPC Class Codes: H04N 19/63 : using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 21/234327 : by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/2383 : Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/426 : Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4382 : Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/4383 : Accessing a communication channel
• CPC Class Codes: H04N 21/440272 : for performing aspect ratio conversion
• CPC Class Codes: H04N 21/44209 : Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896
• CPC Class Codes: H04N 21/4425 : Monitoring of client processing errors or hardware failure
• CPC Class Codes: H04N 21/4621 : Controlling the complexity of the content stream or additional data, e.g. lowering the resolution or bit-rate of the video stream for a mobile client with a small screen arrangements for using the results of monitoring on user's side in broadcast systems H04H60/65; flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/631 : Multimode Transmission, e.g. transmitting basic layers and enhancement layers of the content over different transmission paths or transmitting with different error corrections, different keys or with different transmission protocols
• CPC Class Codes: H04N 5/455 : Demodulation-circuits
• CPC Class Codes: H04N 7/015 : High-definition television systems
• CPC Class Codes: H04N 7/24 : Systems for the transmission of television signals using pulse code modulation H04N21/00 takes precedence

Abstract

At the transmitter side, carrier waves are modulated according to an input signal for producing relevant signal points in a signal space diagram. The input signal is divided into, two, first and second, data streams. The signal points are divided into signal point groups to which data of the first data stream are assigned. Also, data of the second data stream are assigned to the signal points of each signal point group. A difference in the transmission error rate between first and second data streams is developed by shifting the signal points to other positions in the space diagram. At the receiver side, the first and/or second data streams can be reconstructed from a received signal. In TV broadcast service, a TV signal is divided by a transmitter into, low and high, frequency band components which are designated as a first and a second data stream respectively. Upon receiving the TV signal, a receiver can reproduce only the low frequency band component or both the low and high frequency band components, depending on its capability.

Claims

1. A communication system comprising:

a transmitter having a signal input means for receiving a signal, a modulating means for producing m signal points, where m is an integer not less than 4, in a signal space diagram through modulation of a carrier wave using an input signal fed from the signal input means, and a transmitting means for transmitting a modulated signal, in which the main procedure includes receiving the input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, assigning n values of the first data stream to the n signal point groups respectively, assigning data of the second data stream to the signal points of each signal point group, and encoding said first and/or second data streams in a Trellis encoder.

4. A communication system in accordance with claim 1, wherein said input signal is a video signal which is divid d into a high frequency band video signal and a low frequency band video signal, and further said low and high frequency band video signals are transmitted as said first and second data streams.

7. A communication system in accordance with claim 1, wherein said input signal is a video signal which is divided into three, high, medium, and low, frequency band video signals, said high frequency band video signal is transmitted as said second data stream, and said low and medium frequency band video signals being 1-1 and 1-2 data streams respectively are time multiplexed and transmitted as said first data stream.

8. A communication system in accordance with claim 4, wherein only said second data stream is encoded in the Trellis encoder.

9. A communication system in accordance with claim 7, wherein said 1-1 and 1-2 data streams are encoded in an error correcting encoder, and an error correcting code gain of said 1-1 data stream is set higher than that of said 1-2 data stream.

37. A communication system in accordance with claim 1, wherein a transmission or reception of said second data stream is interrupted when a code error rate of said second data stream is increased during transmission or reception of said first and second data streams.

2. A communication system comprising:

a receiver having a signal input means for receiving a modulated signal, a demodulating means for demodulating a received QAM signal representing P signal points in a signal space diagram, and an output means for outputting a demodulated signal, in which the main procedure includes dividing the P signal points into n signal point groups, demodulating a first data stream of which n values are assigned to the n signal point groups, demodulating a second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data stream, and decoding said first and/or second data streams in a Trellis decoder.

5. A communication system in accordance with claim 2, wherein said modulated signal is a video signal including a low frequency band video signal of the first data stream and a high frequency band video signal of the second data stream, and a video signal is reconstructed from said high and low frequency band signals.

10. A communication system in accordance with claim 2, wherein said modulated signal is a video signal consisting of three, high, medium, and low, frequency band video signals, said high frequency band signal is received as said second data stream, said first data stream is time divided and demodulated as a 1-2 data stream of the medium frequency band video signal and a 1-1 data stream of the low frequency band video signal.

11. A communication system in accordance with claim 5, wherein only said second data stream is decoded in the Trellis decoder.

12. A communication system in accordance with claim 10, wherein said 1-1 and 1-2 data streams are decoded in an error correcting decoder, and an error correcting code gain of said 1-1 data stream is set higher than that of said 1-2 data stream.

38. A communication system in accordance with claim 2, wherein only said first data stream data is received for a predetermined period of time when a code error rate of said second data stream is increased during a reception of said first and second data streams.

3. A communication system comprising:

a transmitter having a signal input circuit, a modulator circuit for producing m (m≧

4) signal points in a signal space diagram through modulation of a carrier wave using an input signal fed from the signal input circuit, and a transmitter circuit for transmitting a modulated signal, in which a main procedure includes receiving the input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, assigning n values of the first data stream to the n signal point groups respectively, assigning data of the second data stream to the signal points of each signal point group, and encoding at least one of said first and second data streams by a Trellis encoder; and

a receiver having an input circuit for reception of said modulated signal transmitted from the transmitter, a demodulator circuit for demodulating a QAM modulated multi-level signal representing P signal points in a signal space diagram, and an output circuit, in which the main procedure includes dividing the P signal points into signal point groups, demodulating the first data stream of which n values are assigned to the n signal point groups, demodulating the second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data streams, and decoding at least one of said first and second data streams in a Tr his decoder.

6. A communication system in accordance with claim 3, wherein said input signal is a video signal which is divided into a high frequency band video signal and a low frequency band video signal, and further said low and high frequency band video signals are transmitted as said first and second data streams.

13. A recording/playback system comprising:

a recording means having a signal input means for receiving a signal, a modulating means for producing m signal points, where m is an integer not less than 4, in a signal space diagram through modulation of a carrier wave using an input signal fed from the signal input means, and a recording means for recording a modulated signal on a recording medium, in which the main procedure includes receiving the input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, assigning n values of the first data stream to the n signal point groups respectively, and assigning data of the second data stream to the signal points of each signal point group.

16. A recording/playback system in accordance with claim 13, wherein said input signal is a video signal which is divided into a high frequency band video signal and a low frequency band video signal, and further said low and high fr quency band video signals are recorded as said first and second data streams.

19. A recording/playback system in accordance with claim 13, wherein said input signal is a video signal which is divided into three, high, medium, and low, frequency band video signals, said high frequency band video signal is recorded as said second data stream, and said low and medium frequency band video signals being 1-1 and 1-2 data streams respectively are time multiplexed and recorded as said first data stream.

20. A recording/playback system in accordance with claim 16, wherein at least either of said first and second data streams is encoded in a Trellis encoder.

21. A recording/playback system in accordance with claim 19, wherein said 1-1 and 1-2 data streams are encoded in an error correcting encoder, and an error correcting code gain of said 1-1 data stream is set higher than that of said 1-2 data stream.

14. A recording/playback system comprising:

a playback means having a signal reproducing means for reproducing a recorded signal from a recording medium, a demodulating means for demodulating a received QAM signal representing P signal points in a signal space diagram, and an output means for outputting a demodulated signal, in which the main procedure includes dividing the P signal points into n signal point groups, demodulating a first data stream of which n values are assigned to the n signal point groups, and demodulating a second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data stream.

17. A recording/playback system in accordance with claim 14, wherein said recorded signal is a video signal including a low frequency band video signal of the first data stream and a high frequency band video signal of the second data stream, and a video signal is reconstructed from said high and low frequency band signals.

22. A recording/playback system in accordance with claim 17, wherein at least either of said first and second data streams is decoded in a Trellis decoder.

23. A recording/playback system in accordance with claim 14, wherein said recorded signal is a video signal consisting of three, high, medium, and low, frequency band video signals, said high frequency band signal is received as said second data stream, said first data stream is time divided and demodulated as a 1-2 data stream of the medium frequency band video signal and a 1-1 data stream of the low frequency band video signal.

24. A communication system in accordance with claim 23, wherein said 1-1 and 1-2 data streams are decoded in an error correcting decoder, and an error correcting code gain of said 1-1 data stream is set higher than that of said 1-2 data stream.

15. A recording/playback system comprising:

a recorder having a signal input circuit, a modulator circuit for producing m (m≧

4) signal points in a signal space diagram through modulation of a carrier wave using an input signal fed from the signal input circuit, and a recording circuit for recording a modulated signal on a recording medium, in which a main procedure includes receiving th input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, and assigning n values of the first data stream to the n signal point groups respectively, assigning data of the second data stream to the signal points of each signal point group; and

a playback unit having a signal reproducing circuit for reproducing a recorded signal from said recording medium, a demodulating circuit for demodulating a received QAM signal representing P signal points in a signal space diagram, and an output circuit for outputting a demodulated signal, in which the main procedure includes dividing the P signal points into n signal point groups, demodulating a first data stream of which n values are assigned to the n signal point groups, and demodulating a second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data stream.

18. A recording/playback system in accordance with claim 15, wherein said input signal is a video signal which is divided into a high frequency band video signal and a low frequency band video signal, and further said low and high frequency band video signals are recorded as said first and second data streams.

25. A communication system comprising:

a transmitter of OFDM type in which an input signal is serial to parallel converted into a plurality of input signals and then transmitted through modulation in a plurality of modulators whose carrier waves are 90°

-out-of-phase with each other, each of said modulators having a signal input means for receiving an input signal, a modulating means for producing m signal points, where m is an integer not less than 4, in a signal space diagram through modulation of said carrier wav using an input signal fed from the signal input means, and a transmitting means for transmitting a modulated signal, in which the main procedure includes receiving the input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, assigning n values of the first data stream to the n signal point groups respectively, and assigning data of the second data stream to the signal points of each signal point group.

28. A communication system in accordance with claim 25, wherein said input signal is a video signal which is divided into a high frequency band video signal and a low frequency band video signal, and further said low and high frequency band video signals are transmitted as said first and second data streams.

31. A communication system in accordance with claim 25, wherein said input signal is a video signal which is divided into three, high, medium, and low, frequency band video signals, said high, medium, and low frequency band video signals are transmitted as said second, a 1-2, and 1-1 data streams respectively.

32. A communication system in accordance with claim 28, wherein at least either of said first and second data streams is encoded in a Trellis encoder.

33. A communication system in accordance with claim 31, wherein said 1-1 and 1-2 data streams ar ncoded in an error correcting encoder, and an error correcting code gain of said 1-1 data stream is set higher than that of said 1-2 data stream.

26. A communication system comprising:

a receiver having a signal input means for converting a modulated signal into a plurality of carrier waves in an FFT converter, a demodulating means for demodulating a receiv d QAM signal representing P signal points in a signal space diagram, and an output means for outputting a demodulated signal, in which the main procedure includes dividing the P signal points into n signal point groups, demodulating a first data stream of which n values are assigned to the n signal point groups, and demodulating a second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data stream.

29. A communication system in accordance with claim 26, wherein said modulated signal is a video signal including a low frequency band video signal of the first data stream and a high frequency band video signal of the second data stream, and a video signal is reconstructed from said high and low frequency band signals.

34. A communication system in accordance with claim 26, wherein said modulated signal is a video signal consisting of three, high, medium, and low, frequency band video signals, said high frequency band signal is received as said second data stream, said first data stream is time divided and demodulated as a 1-2 data stream of the medium frequency band video signal and a 1-1 data stream of the low frequency band video signal.

35. A communication system in accordance with claim 29, wherein at least either of said first and second data streams is decoded in a Trellis decoder.

36. A communication system in accordance with claim 34, wherein said 1-1 and 1-2 data streams are decoded in an error correcting decoder, and an error correcting code gain of said 1-1 data stream is set higher than that of said 1-2 data stream.

27. A communication system comprising:

a transmitter of OFDM type in which an input signal is serial to parallel converted into a plurality of input signals and then transmitted through modulation in a plurality of modulators whose carrier waves are 90°

-out-of-phase with each other, each of said modulators having a signal input circuit for receiving an input signal, a modulating circuit for producing m (m≧

4) signal points in a signal space diagram through modulation of said carrier wave using an input signal fed from the signal input circuit, and a transmitting circuit for transmitting a modulated signal, in which the main procedure includes receiving the input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, assigning n values of the first data stream to the n signal point groups respectively, and assigning data of the second data stream to the signal points of each signal point group; and

a receiver having a signal input circuit for converting said modulated signal transmitted from said transmitting circuit into a plurality of carrier waves in an FFT converter, a demodulating circuit for demodulating a received QAM signal representing P signal points in a signal space diagram, and an output circuit for outputting a demodulated signal, in which the main procedure includes dividing the P signal points into n signal point groups, demodulating a first data stream of which n values are assigned to the n signal point groups, and demodulating a second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data stream.

30. A communication system in accordance with claim 27, wherein said input signal is a video signal which is divided into a high frequency band video signal and a low frequency band video signal, and further said low and high frequ ncy band video signals are transmitted as said first and second data streams.