Method, system and apparatus for transmitting, receiving, and reproducing a digital broadcast signal

• US 6,535,717 B1
• Filed: 08/31/1999
• Issued: 03/18/2003
• Est. Priority Date: 08/31/1998
• Status: Expired due to Fees

• Current Assignee: Fujitsu Advanced Engineering Limited (Fujitsu Limited), Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Saito, Takashi, Okubo, Hiroshi, Yokoyama, Hideaki, Katoh, Tadayoshi, Matsushima, Kazuhisa
• Primary Examiner(s): Legree, Tracy
• Application Number:
  US09/387,157
• Time in Patent Office: 1,295 Days
• Field of Search: 455/10, 455/11.1, 455/12.1, 455/18, 455/427, 455/414, 455/450, 455/451, 455/454, 455/15, 455/3.01, 455/3.02, 370/343, 370/344, 370/316, 370/410, 725/114, 725/116, 725/117, 348/14.12, 375/240.12
• US Class Current: 455/18
• CPC Class Codes: H04H 20/16 Arrangements for broadcast or for distribution of identical information repeatedly
• CPC Class Codes: H04H 20/28 Arrangements for simultaneous broadcast of plural pieces of information
• CPC Class Codes: H04H 20/74 of satellite networks
• CPC Class Codes: H04H 60/12 wherein another information is substituted for the portion of broadcast information
• CPC Class Codes: H04L 1/04 using frequency diversity
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 21/23439 for generating different versions
• CPC Class Codes: H04N 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/41407 embedded in a portable device, e.g. video client on a mobile phone, PDA, laptop constructional details of equipment or arrangements specially adapted for portable computer application G06F1/1626; arrangements specially adapted for mobile receivers in broadcast systems H04H20/57
• CPC Class Codes: H04N 21/4347 Demultiplexing of several video streams
• 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

Abstract

The present system comprises a transmitting apparatus for digital broadcast which includes an original signal generating section, delaying section, information amount reducing section, and transmitting section. A receiving and reproducing apparatus for digital broadcast includes a signal reception front stage unit for receiving a high quality signal and a low quality signal, mode determining section and reproducing section composed of a delaying section and selecting section for selectively reproducing the high quality signal and the low quality signal. By employing time diversity, the transmitting apparatus sends the low quality signal having a smaller bandwidth and the high quality signal so that the low quality signal has a preceding time lag relative to the high quality signal, and the receiving apparatus reproduces broadcasting programs. Utilizing the frequency band for broadcast effectively, many broadcasting programs can be increased, and the investment for providing a gap filler can be minimized.

Claims

1. A method of transmitting a signal from a transmitting side and receiving and reproducing the transmitted signal on a receiving side in a digital broadcasting situation, the method carried out in such a manner that:

on the transmitting side, a high quality signal is created based on broadcast digital data and at least one low quality signal is created based on the same broadcast digital data, the low quality signal being created by reducing an information data amount of the high quality signal, so that the quality of the low quality signal is low with respect to that of the high quality signal, and the high-quality signal and the low quality signal are transmitted so that one of the signals has a time lag relative to the other, the high quality signal is transmitted by using a first channel band while the low quality signal is transmitted by using a second channel band of which width is narrower than that of the first channel band, the low quality signal being transmitted before the high quality signal is transmitted from the transmitting side, and

on the receiving side, the receiving side including mode determining means for determining which of a normal receiving mode and a broadcast hindrance mode is effected, and reproducing means for reproducing the high quality signal when the normal receiving mode is effected while reproducing the low quality signal when the broadcast hindrance mode is effected, the reproducing means reproduces the high quality signal when the mode determining means determines a normal receiving mode is effected while the reproducing means reproduces the low quality signal when the mode determining means determines the broadcast hindrance mode is effected.

2. A method according to claim 1, wherein on the transmitting side a plurality of low quality signals different in quality from one another are prepared as the low quality signal, and the high quality signal and the plurality of low quality signals are transmitted so that each of the signals has a time lag relative to another.

3. A method according to claim 1, wherein the high quality signal is transmitted by using a first channel band while each of the low quality signals is transmitted by using a second channel band of which each width of the low quality signals is narrower than that of the first channel band.

4. A method according to claim 3, wherein each of the second channel bands is different from one another.

5. A method according to claim 1, wherein when transition is brought about from the normal receiving mode to the broadcast hindrance mode on the receiving side, the high quality signal and the low quality signal are processed and reproduced so that continuous change is effected in terms of quality from the high quality signal to the low quality signal.

6. A method according to claim 1, wherein when transition is brought about from the broadcast hindrance mode to the normal receiving mode on the receiving side, the high quality signal and the low quality signal are processed and reproduced so that continuous change is effected in terms of quality from the high quality signal to the low quality signal.

7. A method of transmitting a signal from a transmitting side and receiving and reproducing the transmitted signal on a receiving side in a digital broadcasting situation, the method carried out in such a manner that:

on the transmitting side, a high quality signal is created based on broadcast digital data and at least one low quality signal is created based on the same broadcast digital data so that the quality of the low quality signal is low with respect to that of the high quality signal, and the high quality signal and the low quality signal are transmitted so that one of the signals has a time lag relative to the other; and

on the receiving side, the high quality signal is reproduced when a normal receiving mode is effected while the low quality signal is reproduced when a broadcast hindrance mode is effected;

wherein on the receiving side, after the broadcast hindrance mode takes place, transition to the normal receiving mode is prohibited for reproducing the high quality signal until the high quality signal is successfully received for a predetermined time duration or predetermined number of frames.

8. A method of transmitting a signal from a transmitting side and receiving and reproducing the transmitted signal on a receiving side in a digital broadcasting situation, the method carried out in such a manner that:

on the transmitting side, a high quality signal is created based on broadcast digital data and at least one low quality signal is created based on the same broadcast digital data so that the quality of the low quality signal is low with respect to that of the high quality signal, and the high quality signal and the low quality signal are transmitted so that one of the signals has a time lag relative to the other; and

on the receiving side, the high quality signal is reproduced when a normal receiving mode is effected while the low quality signal is reproduced when a broadcast hindrance mode is effected;

wherein on the receiving side, if the low quality signal is not received but the high quality signal is received under condition that the broadcast hindrance mode is effected, low quality data is created from the high quality signal to recover the reproduction of the low quality signal.

9. A system composed of a transmitting apparatus for transmitting a signal and a receiving apparatus for receiving and reproducing the signal transmitted from the transmitting apparatus, both of the apparatus working in a digital broadcasting situation, the transmitting apparatus comprising:

high quality signal creating means for creating a high quality signal based on broadcast digital data;

low quality signal creating means for creating at least one low quality signal based on the same broadcast digital data, the low quality signal being created by reducing an information data amount of the high quality signal, so that the quality of the low quality signal is low with respect to that of the high quality signal; and

transmitting means for transmitting the high quality signal created by the high quality signal creating means and the low quality signal created by the low quality signal creating means so that one of the signals has a time lag relative to the other, the high quality signal is transmitted by using a first channel band while the low quality signal is transmitted by using a second channel band of which width is narrower than that of the first channel band, the low quality signal being transmitted before the high quality signal is transmitted from the transmitting side, and

the receiving apparatus arranged for receiving the high quality signal and the low quality signal transmitted from the transmitting apparatus, comprising;

mode determining means for determining which of a normal receiving mode and a broadcast hindrance mode is effected; and

reproducing means for reproducing the high quality signal when the normal receiving mode is effected while reproducing the low quality signal when a broadcast hindrance mode is effected.

10. A transmitting apparatus for transmitting broadcasting digital data in a digital broadcasting situation, comprising:

high quality signal creating means for creating a high quality signal based on broadcast digital data;

low quality signal creating means for creating at least one low quality signal based on the same broadcast digital data, the low quality signal being created by reducing an information data amount of the high quality signal, so that the quality of the low quality signal is low with respect to that of the high quality signal; and

transmitting means for transmitting the high quality signal created by the high quality signal creating means and the low quality signal created by the low quality signal creating means so that one of the signals has a time lag relative to the other, the high quality signal is transmitted by using a first channel band while the low quality signal is transmitted by using a second channel band of which width is narrower than that of the first channel band, the low quality signal being transmitted before the high quality signal is transmitted from the transmitting side.

11. A transmitting apparatus according to claim 10, wherein

the high quality signal creating means, the low quality signal creating means and the transmitting means are provided in the same broadcasting station.

12. A transmitting apparatus according to claim 10, wherein

the high quality signal creating means is provided in a broadcasting station, and the low quality signal creating means and the transmitting means are provided in a broadcasting/communication satellite.

13. A transmitting apparatus according to claim 10, wherein

the low quality signal creating means is arranged to create a plurality of low quality signals different in quality from one another, and the transmitting means is arranged to transmit the plurality of low quality signals as well as the high quality signal so that each of the low quality signals and the high quality signal has a time lag relative to another.

14. A transmitting apparatus according to claim 13, wherein

the transmitting means is arranged to create the low quality signal by reducing information data amount of the high quality signal, and transmit the low quality signal before transmitting the high quality signal.

15. A transmitting apparatus according to claim 13, wherein

the high quality signal is transmitted by using a first channel band while each of the low quality signals is transmitted by using a second channel band of which each width of the low quality signals is narrower than that of the first channel band.

16. A transmitting apparatus according to claim 15, wherein

each of the second channel band is different from one another.

17. A transmitting apparatus according to claim 10, wherein the transmitting means is arranged to create the low quality signal by reducing information data amount of the high quality signal, and transmit the low quality signal before transmitting the high quality signal.

18. A transmitting apparatus according to claim 10, wherein

the high quality signal is transmitted by using a first channel band while the low quality signal is transmitted by using a second channel band of which width is narrower than that of the first channel band.

19. A receiving and reproducing apparatus for use with a transmitting apparatus and receiving and reproducing a signal transmitted from the transmitting apparatus in which a high quality signal is created based on broadcast digital data, at least one low quality signal is created based on the same broadcast digital data, the low quality signal being created by reducing an information data amount of the high quality signal, so that the low quality signal is low with respect to that of the high quality signal, and the high quality signal and the low quality signal are transmitted so that one of the signals has a time lag relative to the other, the receiving and reproducing apparatus comprising:

transmitting means for transmitting the high quality signal created by the high quality signal creating means and the low quality signal created by the low quality signal creating means so that one of the signals has a time lag relative to the other, the high quality signal is transmitted by using a first channel band while the low quality signal is transmitted by using a second channel band of which width is narrower than that of the first channel band, the low quality signal being transmitted before the high quality signal is transmitted from the transmitting side;

mode determining means for determining which of a normal receiving mode and a broadcast hindrance mode is effected; and

reproducing means for reproducing the high quality signal when the normal receiving mode is effected while reproducing the low quality signal when the broadcast hindrance mode is effected.

20. A receiving and reproducing apparatus according to claim 19, wherein

the mode determining means is arranged to detect transition going to bring about from the normal receiving mode to the broadcast hindrance mode, and

when the mode determining means detects the transition going to bring about from the normal receiving mode to the broadcast hindrance mode, the high quality signal and the low quality signal are processed and reproduced so that continuous change is effected in terms of quality of the high quality signal and the low quality signal.

21. A receiving and reproducing apparatus according to claim 19, wherein

the mode determining means is arranged such that, under condition that the broadcast hindrance mode is effected, the mode determining means does not determine that it is allowable for the normal receiving mode to take place until the high quality signal is successfully received for a predetermined time duration or predetermined number of frames, and

the reproducing means is arranged such that, when the mode determining means determines that it is allowable for the transition from the broadcast hindrance mode to the normal receiving mode to bring about, the reproducing means reproduces the high quality signal.

22. A receiving and reproducing apparatus according to claim 19, wherein

the reproducing means is arranged such that, if the low quality signal is not received but the high quality signal is received under condition that the broadcast hindrance mode is effected, the reproducing means creates low quality data from the high quality signal to recover the reproduction of the low quality signal.

23. A receiving and reproducing apparatus according to claim 19, wherein

the mode determining means arranges to determine transition going to bring about from the broadcast hindrance mode to the normal receiving mode, and

when the mode determining means detects the transition going to bring about from the broadcast hindrance mode to the normal receiving mode, the high quality signal and the quality signal are processed and reproduced so that the transition is effected smoothly in terms of quality of the high quality signal and the low quality signal.

24. A method of transmitting a signal from a transmitting side and receiving and reproducing the transmitted signal on a receiving side in a digital broadcasting situation, the method carried out in such a manner that:

on the transmitting side, a high quality signal is created based on broadcast digital data and at least one low quality signal is created based on the same broadcast digital data so that the quality of the low quality signal is low with respect to that of the high quality signal, and the high quality signal and the low quality signal are transmitted so that one of the signals has a time lag relative to the other; and

on the receiving side, the high quality signal is reproduced when a normal receiving mode is effected while the low quality signal is reproduced when a broadcast hindrance mode is effected;

wherein, after the broadcast hindrance mode is effected on the receiving side, a fact that the high quality signal has been continuously received for a predetermined number of frames, leads to a transition to the normal receiving mode in which the high quality signal is selected for reproduction, using one method chosen of any method;

a cross-fade method which the high quality signal data is weighted with a gradually decreasing weight coefficient while the low quality signal data is weighted with a gradually increasing weight coefficient, and both of the data are overlaid on each other;

an averaging processing method with weighting in such a manner that, between the timing points T1 and T0, a weighting function of which value gradually decreases to zero is applied to the data while between the timing points T0 and T2, a weighting function of which value gradually increases from zero is applied to the data; and

an interpolation and synthesis method which data for interpolation and synthesis may be created from data of the high quality signal and the low quality signal having been received so far and having been subjected to the decoding processing.