Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital data error correction
Reexamination Certificate
2000-12-12
2004-01-20
Dildine, R. Stephen (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital data error correction
C714S776000, C714S784000, C714S804000
Reexamination Certificate
active
06681363
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a data transmission system and a data transmission and receiving apparatus, more particularly to a data receiving apparatus, a data transmission system, and a data transmission method therefor which relate to broadcasting and communication of digitized sound and image data and other data information, which receive data by a simple receiving method stressing real time and low power consumption at the time of BGM or free distribution and broadcasting, which allow highly reliable data reception at the time of storing received data or pay distribution and broadcasting, and which otherwise enable control of data reliability and receiving cost according to the mode of reception and which establish a charging system for distribution and broadcasting.
BACKGROUND ART
In the field of data transmission, especially in digital broadcasting, a transmission side encodes image, sound, and other source data, multiplexes the encoded data, applies channel encoding, and sends the data through an antenna or a transmission line. A receiving side basically applies processing reverse to that performed at the transmission side to reproduce the original data forming the source. In other words, it performs channel decoding, demultiplexing, and source decoding.
FIG. 5
shows an example of the configuration of a basic data transmission system. Here, the explanation is given assuming two kinds of sources. In
FIG. 5
,
5
and
6
are source data. Note that these source data include, for example, sound data, image data, composite data corresponding to a composite signal including both sound and image signals such as a TV signal, and computer information data such as software and databases handled by computers.
In
FIG. 5
,
10
and
11
are information-data generation circuits for performing predetermined processing on the source data
5
and
6
, while
12
and
13
are information data generated by the information-data generation circuits
10
and
11
. Reference numeral
14
shows a multiplexing circuit. The multiplexing circuit
14
multiplexes the information data
12
and
13
by a predetermined method to obtain the multiplexed data
15
. Reference numeral
16
is a channel encoding circuit comprised of an encoding circuit
29
and a modulation circuit
30
. The encoding circuit
29
performs error-correcting coding by a predetermined method. The modulation circuit
30
performs digital modulation by a predetermined method. Reference numeral
17
is channel-encoded data (hereinafter called transmission data). Reference numeral
18
is a transmission line. Here, the transmission line
18
is, for example, an electromagnetic wave.
In the transmission line
18
, noise
28
is added to the transmission signal
17
from a noise source
27
. Reference numeral
19
is a transmission signal to which noise is added. This becomes the signal input to a receiving apparatus. Reference numeral
20
is a channel decoding circuit comprised of a digital demodulator
31
and an error-correcting decoder
32
. The digital demodulator
31
performs digital demodulation by a predetermined method. The error-correcting decoder
32
performs error-correcting decoding by a predetermined method. Reference numeral
21
is a channel-decoded result, while
22
is a demultiplexer. The demultiplexer
22
demultiplexes the data by a predetermined method. Reference numeral
23
is demultiplexed data corresponding to the information data
12
, while
25
is an source reproduction circuit. Reference numeral
24
is demultiplexed data corresponding to the information data
13
, while
26
is an source reproduction circuit. Source-reproduced data
33
and
34
are viewed and listened to in real time or stored in a storage medium such as tape or a disk. Data to be transmitted is shown in FIG.
6
. Here, the data to be transmitted is, for example, a TS (transport stream) of MPEG-2 Systems (ITU-TH, 222, 0, ISO/IEC 13818-1). In this case,
12
and
13
shown in
FIG. 5
are TS's of information data corresponding to the source data
5
and
6
, respectively. The output of the multiplexing circuit
14
, that is, the multiplexed data
15
, is a TS comprised of the information data
12
and
13
multiplexed.
A TS is comprised of TSP's (transport stream packets). A TSP, as shown in
FIG. 6
, is a fixed-length packet comprised of a total of 188 bytes including a synchronization byte (O×47), a TS header (four bytes including the synchronization byte), and a data section of 184 bytes. The TS header includes a packet identifier, that is, PID (packet ID). The demultiplexer
22
at the receiving side demultiplexes the TSP's corresponding to the information data
12
and
13
based on the unique PID's assigned to the TS's of the information data
12
and
13
at the multiplexing circuit
14
of the transmission side. The TS header also includes an error indication flag (transport error indicator). If error is included in the corresponding TSP, the error indicating flag becomes 1, while if error is not included, the error indicating flag becomes 0. The receiving side usually discards or otherwise processes a TSP including error. The data section of 184 bytes can be one of three types: a payload (FIG.
6
(A)), an adaptation field (FIG.
6
(B)), and a payload and adaptation field (FIG.
6
(C)).
Here, while the data is demultiplexed by the demultiplexer
22
based on the PID's, since the noise
28
is added to the transmission data
17
on the transmission line
18
, if the channel-decoded data
21
includes error, the PID may have error and correct demultiplexing may not be possible. In this case, the demultiplexed data
23
corresponding to the information data
12
of the transmission side may be missing some TSP's and this will affect the source decoding. In other words, the drawback will occur of the image or sound being disturbed or interrupted. Note that the same applies to the demultiplexed data
24
corresponding to the information data
13
of the transmission side.
To keep these drawbacks to the minimum, error control is required when transmitting data over a transmission line having error. Error control is usually performed by the error-correcting coding circuit
29
in the channel encoding circuit
16
. In particular, in transmission by a transmission medium having poor conditions such as in urban areas in terrestrial transmission, mobile reception, and at boundaries of service areas, the above loss of TSP's frequently occurs and the reliability of the data becomes a problem. For example, when a received signal is stored in a storage medium such as tape or disk for use, especially in the case of a pay service offered along with the future digitalization of communication and broadcasting, not only will the occurrence of error itself become a problem, but also the charging for error-ridden data may cause a serious problem. As a means for solving this problem, the method of making error correction more powerful etc. can be considered, but in general, if performing powerful error correction, the amount of processing for the decoding at the receiving side can be expected to also increase and the size of the receiving apparatus or the increased power consumption will become a problem. Further, in broadcasting, where real time is demanded, the delay caused by the decoding is desirably made as short as possible. Therefore, another means is desired.
The present invention has been made in consideration of the foregoing situation and has as its object is to provide a transmission system which allows highly real-time, simple decoding, while allowing error, when performing powerful error correction and which performs processing which allows a sufficient error-correcting characteristic to be achieved by performing predetermined processing. In addition, the present invention provides means for normally simply decoding the data transmitted by the above transmission system at a receiving side for viewing and listening, but, if necessary performing a predetermined erro
Ikeda Tamotsu
Ikeda Yasunari
Kawaguchi Moriyuki
Okada Takahiro
Tagawa Koichi
Dildine R. Stephen
Frommer William S.
Frommer & Lawrence & Haug LLP
Simon Darren M.
Sony Corporation
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