DESCRIPTION
DATA PROCESSING DEVICES AND DATA PROCESSING METHODS
TECHNICAL FIELD
5 [0001]
The present technology relates to data processing
devices and data processing methods, and more
particularly, to data processing devices and data
processing methods that lower costs and enable CB
10 (Channel Bonding), for example.
BACKGROUND ART
[0002]
Examples of transmission standards in digital
15 broadcasting include DVB-C2, which is next-generation
cable television standards and is standardized by DVB
(Digital Video Broadcasting) (Non-Patent Document 1).
[0003]
In DVB-C2, high-efficiency modulation methods and
20 encoding methods are specified.
CITATION LIST
NON-PATENT DOCUMENT
[0004]
25 Non-Patent Document 1: DVB-C.2 :ETSI EN 302 769
V1.2.1 (2011-04)
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
30 [0005]
As a technique for transmitting a stream with a
3
high data rate in digital broadcasting, there is CB
(Channel Bonding) by which a stream with a high data rate
is divided into divisional streams of (channels) and is
transmitted from the transmitting side, and the original
stream with the high data rate is recomposed 5 from the
divisional streams on the receiving side.
[0006]
In DVB-C2, PLP (Physical Layer Pipe) bundling is
specified as a kind of CB.
10 [0007]
In DVB-C2, however, the details of PLP bundling are
not specified at present. Therefore, if some degree of
freedom is allowed in PLP bundling on the transmitting
side, the apparatus that recomposes the original stream
15 with a high data rate on the receiving side might require
higher costs than before.
[0008]
The present technology has been made in view of
these circumstances, and aims to lower costs and enable
20 CB such as PLP bundling.
SOLUTIONS TO PROBLEMS
[0009]
A first data processing device of the present
25 technology is a data processing device including a
dividing unit that divides a BB stream as a stream of BB
(Baseband) frames into divisional streams by distributing
the BB frames of the BB stream to data slices, the
dividing unit dividing the BB stream by limiting the data
30 rate ratio between the data rates of the divisional
streams.
4
[0010]
A first data processing method of the present
technology is a data processing method including the step
of dividing a BB stream as a stream of BB (Baseband)
frames into divisional streams by distributing 5 the BB
frames of the BB stream to data slices, the dividing of
the BB stream being performed by limiting the data rate
ratio between the data rates of the divisional streams.
[0011]
10 In the first data processing device and data
processing method of the present technology, a BB stream
as a stream of BB (Baseband) frames is divided into
divisional streams by distributing the BB frames of the
BB stream to data slices. The dividing of the BB stream
15 is performed by limiting the data rate ratio between the
data rates of the divisional streams.
[0012]
A second data processing device of the present
technology is a data processing device including a
20 recomposing unit that recomposes an original BB stream as
a stream of BB (Baseband) frames from divisional streams
transmitted from a transmission device, the transmission
device including a dividing unit that divides the BB
stream into the divisional streams by distributing the BB
25 frames of the BB stream to data slices, the dividing unit
dividing the BB stream by limiting the data rate ratio
between the data rates of the divisional streams.
[0013]
A second data processing method of the present
30 technology is a data processing method including the step
of recomposing an original BB stream as a stream of BB
5
(Baseband) frames from divisional streams transmitted
from a transmission device, the transmission device
including a dividing unit that divides the BB stream into
the divisional streams by distributing the BB frames of
the BB stream to data slices, the dividing 5 unit dividing
the BB stream by limiting the data rate ratio between the
data rates of the divisional streams.
[0014]
In the second data processing device and data
10 processing method of the present technology, an original
BB stream as a stream of BB (Baseband) frames is
recomposed from divisional streams transmitted from a
transmission device, the transmission device including a
dividing unit that divides the BB stream into the
15 divisional streams by distributing the BB frames of the
BB stream to data slices, the dividing unit dividing the
BB stream by limiting the data rate ratio between the
data rates of the divisional streams.
[0015]
20 It should be noted that a data processing device
may be an independent device, or may be an internal block
in a single device.
EFFECTS OF THE INVENTION
25 [0016]
According to the present technology, CB can be
performed at lowered costs.
[0017]
The effects of the present technology are not
30 limited to the effects described herein, and may include
any of the effects described in this disclosure.
6
BRIEF DESCRIPTION OF DRAWINGS
[0018]
Fig. 1 is a block diagram showing an example
structure of an embodiment of a transmission 5 system to
which the present technology is applied.
Fig. 2 is a block diagram showing a first example
structure of a transmission device 11.
Fig. 3 is a diagram for explaining the relationship
10 between PLPs and data slices to be processed in the
transmission device 11.
Fig. 4 is a block diagram showing a first example
structure of a reception device 12.
Fig. 5 is a block diagram showing a second example
15 structure of the transmission device 11.
Fig. 6 is a flowchart for explaining an example of
the process (transmission process) to be performed by the
transmission device 11 in a case where data is
transmitted by PLP bundling.
20 Fig. 7 is a diagram showing the format of a BB
frame in HEM.
Fig. 8 is a diagram showing the formats of ISSYs
included in BB headers.
Fig. 9 is a diagram for explaining the relationship
25 between PLPs and data slices to be processed in the
transmission device 11.
Fig. 10 is a block diagram showing a second example
structure of the reception device 12.
Fig. 11 is a flowchart for explaining an example of
30 the process (reception process) to be performed by the
reception device 12 in a case where data transmitted by
7
PLP bundling is received.
Fig. 12 is a diagram showing an example of a method
of dividing a BB stream into divisional streams by
distributing BB frames among data slices in PLP bundling.
Fig. 13 is a diagram showing 5 an example of
divisional streams DS#0 and #1 to be transmitted with
data slices DS#0 and DS#1, respectively, in a case where
the transmission rate ratio between the transmission
rates of the data slices DS#0 and DS#1 is 2.2 : 1.
10 Fig. 14 is a diagram for explaining an example of
control on distribution of BB frames to the data slices
DS#0 and DS#1 in accordance with the transmission rate
ratio between the data slices DS#0 and DS#1 in a case
where a BB stream is divided into the divisional streams
15 DS#0 and #1.
Fig. 15 is a block diagram showing an example
structure of an embodiment of a computer to which the
present technology is applied.
20 MODES FOR CARRYING OUT THE INVENTION
[0019]
[One Embodiment of a Transmission System to Which
the Present Technology Is Applied]
[0020]
25 Fig. 1 is a block diagram showing an example
configuration of an embodiment of a transmission system
to which the present technology is applied (a "system"
means a logical assembly of devices, and the devices with
respective structures are not necessarily housed in the
30 same housing).
[0021]
8
In Fig. 1, the transmission system includes a
transmission device 11 and a reception device 12.
[0022]
The transmission device 11 transmits television
programs and the like (digital broadcasting) 5 (data
transmission). That is, the transmission device 11
transmits (sends) a stream of data to be transmitted,
such as image data and audio data as a television program,
via a transmission channel 13 that is a cable television
10 network (a cable channel), in accordance with the DVB-C2
standards, for example.
[0023]
The reception device 12 receives data transmitted
from the transmission device 11 via the transmission
15 channel 13, and restores and outputs the original stream.
[0024]
The transmission system shown in Fig. 1 can be used
not only for data transmission compliant with the DVB-C2
standards, but also for data transmission compliant with
20 standards such as DVB-T2, DVB-S2, or ATSC (Advanced
Television Systems Committee) standards, and other types
of data transmission.
[0025]
The transmission channel 13 is not necessarily a
25 cable television network, but may be a satellite channel
or a terrestrial channel, for example.
[0026]
[First Example Structure of the Transmission Device
11]
30 [0027]
Fig. 2 is a block diagram showing a first example
9
structure of the transmission device 11 shown in Fig. 1.
[0028]
In Fig. 2, the transmission device 11 includes N (>
1) data slice processing units 211, 212, ..., 21N, a frame
composing unit 22, an IFFT (Inverse 5 Fast Fourier
Transform) unit 23, a DAC (Digital to Analog Converter)
24, and a modulating unit 25.
[0029]
Each data slice processing unit 21n (n = 1, 2, ...,
10 N) generates a data slice DS#n-1 as the nth data slice by
processing (a stream) of actual data as target data such
as a TS (Transport Stream), and supplies the data slice
DS#n-1 to the frame composing unit 22.
[0030]
15 That is, each data slice processing unit 21n
includes M (> 0) PLP processing units 311, 312, ..., 31M,
a data slice composing unit 32, and a time/frequency
interleaver 33.
[0031]
20 Each PLP processing unit 31m (m = 1, 2, ..., M)
generates a data slice packet of a PLP by processing
actual data as the PLP, and supplies the data slice
packet to the data slice composing unit 32.
[0032]
25 Here, a PLP is (the data to be transmitted through)
a logical channel included in a data slice, and a unique
PLP_ID for identifying the PLP is attached to the PLP.
The PLP having a certain PLP_ID is equivalent to the
actual data of a certain television program. Different
30 PLP processing units 31m and 31m process PLPs having
different PLP_IDs from each other. Hereinafter, a PLP
10
having “i” as its PLP_ID will be also written by PLP#i.
[0033]
Among all the data slice processing units 211
through 21N, the numbers M of the PLP processing units
311 through 31M are not necessarily the 5 same. However,
for ease of explanation, the numbers M of the PLP
processing units 311 through 31M are the same among all
the data slice processing units 211 through 21N in this
example.
10 [0034]
Each PLP processing unit 31m includes a data
processing unit 41, an FEC (Forward Error Correction)
unit 42, a mapping unit 43, and a data slice packet
composing unit 44.
15 [0035]
Actual data is supplied to the data processing unit
41.
[0036]
The data processing unit 41 composes a BB
20 (Baseband) frame by attaching a BB header to a
predetermined unit (a predetermined number of TS packets,
for example) of actual data supplied thereto, and
supplies the BB frame to the FEC unit 42.
[0037]
25 The FEC unit 42 performs error correction encoding
such as BCH encoding and LDPC encoding on the BB frame
supplied from the data processing unit 41, and supplies
the resultant FEC frame to the mapping unit 43.
[0038]
30 The mapping unit 43 maps the FEC frame supplied
from the FEC unit 42 as signal points in a constellation
11
defined by a modulation method for predetermined digital
orthogonal modulation, on a symbol-by-symbol basis, each
symbol being formed with a predetermined number of bits.
The mapping unit 43 supplies the symbols as the mapping
result to the data slice packet composing 5 unit 44 on a
FEC frame basis.
[0039]
The data slice packet composing unit 44 composes a
data slice packet by attaching an FEC frame header to one
10 or two FEC frames supplied from the mapping unit 43.
[0040]
Here, an FEC frame header contains information such
as the PLP_IDs of the PLPs forming the FEC frame having
the FEC frame header attached thereto, the MODCOD
15 indicating the modulation method (MOD) used in the
orthogonal modulation in the mapping of the FEC frame,
the code length in the error correction encoding
performed on the FEC frame, and the like.
[0041]
20 The data slice packet composing unit 44 composes a
data slice packet, and supplies the data slice packet to
the data slice composing unit 32.
[0042]
The data slice composing unit 32 composes a data
25 slice (DS#n-1) from the data slice packets supplied from
the PLP processing units 311 through 31M, and supplies
the data slice to the time/frequency interleaver 33.
[0043]
Here, a data slice is a collection of OFDM
30 (Orthogonal Frequency-Division Multiplexing) cells
transmitting PLPs, and an OFDM cell is data to be
12
transmitted by a subcarrier of OFDM.
[0044]
The time/frequency interleaver 33 interleaves the
data slice supplied from the data slice composing unit 32
in the temporal direction, and further 5 interleaves the
data slice in the frequency direction. The
time/frequency interleaver 33 supplies the data slice
interleaved in the temporal direction and the frequency
direction, to the frame composing unit 22.
10 [0045]
The frame composing unit 22 composes a C2 frame
containing one or more data slices supplied from the data
slice processing units 211 through 21N, and supplies the
C2 frame to the IFFT unit 23.
15 [0046]
The IFFT unit 23 performs IFFT on the C2 frame
supplied from the frame composing unit 22, and supplies
the resultant OFDM signal to the DAC 24.
[0047]
20 The DAC 24 performs DA conversion on the OFDM
signal supplied from the IFFT unit 23, and supplies the
OFDM signal to the modulating unit 25.
[0048]
The modulating unit 25 modulates the OFDM signal
25 supplied from the DAC 24 into an RF (Radio Frequency)
signal, and transmits the RF signal via the transmission
channel 13 (Fig. 1).
[0049]
Fig. 3 is a diagram for explaining the relationship
30 between PLPs and data slices to be processed in the
transmission device 11 shown in Fig. 2.
13
[0050]
In Fig. 3, a data slice is formed with one or more
PLPs.
[0051]
By DVB-C2, the transmission band 5 for transmitting
(RF signals of) OFDM signals is divided into
(approximately) 6-MHz unit bands. Where a transmission
band that is a 6-MHz divisional band is set as a unit
transmission band, the reception device 12 receives an
10 OFDM signal of a unit transmission band in which a data
slice DS#n-1 containing the PLPs#i of the actual data of
a desired television program is transmitted, and
processes the data slice DS#n-1 contained in the OFDM
signal.
15 [0052]
[First Example Structure of the Reception Device
12]
[0053]
Fig. 4 is a block diagram showing a first example
20 structure of the reception device 12 shown in Fig. 1.
[0054]
In Fig. 4, the reception device 12 includes a
demodulating unit 51, an ADC (Analog to Digital
Converter) 52, an FFT (Fast Fourier Transform) unit 53, a
25 frame decomposing unit 54, a time/frequency deinterleaver
55, a data slice decomposing unit 56, a data slice packet
decomposing unit 57, a demapping unit 58, an FEC unit 59,
and a data processing unit 60.
[0055]
30 The demodulating unit 51 receives and demodulates
an RF signal in a predetermined band transmitted (sent)
14
from the transmission device 11 via the transmission
channel 13 (Fig. 1), and supplies the resultant
demodulated signal (OFDM signal) to the ADC 52.
[0056]
The ADC 52 performs AD 5 conversion on the
demodulated signal supplied from the demodulating unit 51,
and supplies the resultant digital signal to the FFT unit
53.
[0057]
10 The FFT unit 53 performs FFT on the digital signal
supplied from the ADC 52, and supplies (a signal of) the
resultant C2 frame to the frame decomposing unit 54.
[0058]
The frame decomposing unit 54 extracts the data
15 slice contained in the C2 frame by decomposing the C2
frame supplied from the FFT unit 53, and supplies the
data slice to the data slice decomposing unit 56.
[0059]
The data slice decomposing unit 56 decomposes the
20 data slice supplied from the frame decomposing unit 54
into data slice packets, and supplies the data slice
packets to the data slice packet decomposing unit 57.
[0060]
The data slice packet decomposing unit 57
25 decomposes the data slice packets into FEC frames by
removing the FEC frame header from the data slice packets
supplied from the data slice decomposing unit 56, and
supplies the FEC frames to the demapping unit 58.
[0061]
30 Here, the modulation method for the FEC frames, the
code length, and the like are recognized, and the
15
demapping unit 58 and the FEC unit 59 in the later stages
are controlled based on the FEC frame header removed by
the data slice packet decomposing unit 57.
[0062]
The demapping unit 58 performs 5 demapping on (the
symbols of) the FEC frames supplied from the data slice
packet decomposing unit 57, and supplies the FEC frames
to the FEC unit 59.
[0063]
10 On the FEC frames subjected to the demapping by the
demapping unit 58, the FEC unit 59 performs error
correcting code decoding as the error correction
corresponding to the error correction encoding performed
by the FEC unit 42 shown in Fig. 2. By doing so, the FEC
15 unit 59 restores the BB frame obtained by the data
processing unit 41 shown in Fig. 2, and supplies the BB
frame to the data processing unit 60.
[0064]
The data processing unit 60 decomposes the BB frame
20 supplied from the FEC unit 59, and restores and outputs
(a stream of) actual data.
[0065]
[Second Example Structure of the Transmission
Device 11]
25 [0066]
Fig. 5 is a block diagram showing a second example
structure of the transmission device 11 shown in Fig. 1.
[0067]
In the drawing, the components equivalent to those
30 in Fig. 2 are denoted by the same reference numerals as
those used in Fig. 2, and explanation thereof is not
16
repeated herein.
[0068]
In the transmission device 11 (Fig. 2) having the
first example structure, a PLP#i equivalent to the actual
data of a certain television program is 5 transmitted with
one data slice DS#n-1.
[0069]
There is a limit to the data slice transmission
rate or the transmission rate at which data can be
10 transmitted with one data slice. In a case where the
data rate of one PLP#i as the actual data of a certain
television program exceeds the data slice transmission
rate, it is difficult to transmit the PLP#i with the data
slice.
15 [0070]
Recently, there is a demand for digital
broadcasting to transmit images with a high resolution
such as 8k. In a case where an image with the resolution
of 8k is encoded by HEVC (High Efficiency Video Coding),
20 the throughput required for transmitting the data with a
high data rate obtained as a result of the encoding is
approximately 100 Mbps.
[0071]
As for one PLP#i equivalent to such data with a
25 high data rate, it might be difficult to perform
transmission with one data slice depending on the digital
orthogonal modulation employed in the mapping, the code
rate of the error correcting code employed in the error
correction, or the like.
30 [0072]
In view of this, in the transmission device 11
17
having the second example structure (Fig. 5), actual data
as one PLP#i (PLPs with the same PLP_ID) is divided on a
BB frame basis and can be transmitted with data slices by
PLP bundling, which is a kind of CB.
5 [0073]
It should be noted that Fig. 5 does not show the
blocks not related to PLP bundling.
[0074]
In Fig. 5, the transmission device 11 includes N
10 data slice processing units 211 through 21N, a frame
composing unit 22, an IFFT unit 23, a DAC 24, and a
modulating unit 25. In this aspect, the transmission
device 11 is the same as the first example structure
shown in Fig. 2.
15 [0075]
However, the transmission device 11 shown in Fig. 5
differs from the first example structure shown in Fig. 2,
in that a data processing unit 101 is newly provided.
[0076]
20 Further, the transmission device 11 shown in Fig. 5
differs from the first example structure shown in Fig. 2,
in that each data slice processing unit 21n includes a
PLP processing unit 111, instead of the M PLP processing
units 311 through 31M.
25 [0077]
The PLP processing unit 111 can be provided in
place of one or more of the M PLP processing units 311
through 31M, not in place of all of the M PLP processing
units 311 through 31M.
30 [0078]
The PLP processing unit 111 includes an FEC unit 42,
18
a mapping unit 43, and a data slice packet composing unit
44. In this aspect, the PLP processing unit 111 is the
same as each PLP processing unit 31m shown in Fig. 2.
[0079]
Accordingly, the PLP processing 5 unit 111 performs
the same processing as each PLP processing unit 31m shown
in Fig. 2, except for the processing to be performed by
the data processing unit 41 shown in Fig. 2.
[0080]
10 In Fig. 5, the transmission device 11 divides (a
stream of) actual data as one PLP#i on a BB frame basis
by PLP bundling, and transmits data slices, or three data
slices, for example.
[0081]
15 In the PLP bundling, the number of data slices used
in the transmission of one PLP#i is not limited to three,
but may be two or a value of four or greater.
[0082]
The three data slices to be used in the PLP
20 bundling may be data slices generated by any three of the
N data slice processing units 211 through 21N. In Fig. 5,
data slices DS#0, #1, and #2 generated by the data slice
processing units 211 through 213 are employed as the
three data slices to be used in the PLP bundling.
25 [0083]
The transmission rates of the three data slices
DS#0, #1, and #2 to be used in the PLP bundling (the
transmission rates that can be used in (allocated to) the
PLP bundling in the data slices) are not necessarily the
30 same.
[0084]
19
Since one PLP#i is transmitted with the three data
slices DS#0 through #2 in the transmission device 11
shown in Fig. 5, the data processing unit 101 divides the
actual data as PLPs#i having the same PLP_ID into three
divisional streams corresponding in 5 number to the data
slices DS#0 through #2 to be used in transmission of the
actual data.
[0085]
That is, the actual data as PLPs#i having the same
10 PLP_ID is supplied to the data processing unit 101.
[0086]
Like the data processing unit 41 shown in Fig. 2,
the data processing unit 101 composes a BB frame by
attaching a BB header to the actual data supplied thereto.
15 Further, with a BB stream as the stream of BB frames
being the object to be divided, the data processing unit
101 divides the BB stream into three divisional streams
on a BB frame basis by repeatedly distributing each of
the BB frames constituting the BB stream to one data
20 slice DS#n-1 among the three data slices DS#0 through #2.
[0087]
The data processing unit 101 supplies the
divisional stream formed with the BB frames distributed
to the data slice DS#n-1, to the data slice processing
25 unit 21n.
[0088]
According to DVB-C2, there are NM (Normal Mode) and
HEM (High Efficiency Mode) as the modes for processing
PLPs. In a case where PLP bundling is performed, HEM is
30 employed as the mode for processing PLPs.
[0089]
20
In HEM, an ISSY (Input Stream Synchronizer) is
included in a BB header.
[0090]
An ISSY is time-related information about the
transmission time of data (a BB frame) 5 and the like, and
the data processing unit 101 generates an ISSY, generates
a BB header containing the ISSY, and composes a BB frame
having the BB header.
[0091]
10 Fig. 6 is a flowchart for explaining an example of
the process (transmission process) to be performed by the
transmission device 11 shown in Fig. 5 in a case where
data is transmitted by PLP bundling.
[0092]
15 In the transmission process, the data processing
unit 101 in step S11 places actual data supplied as a PLP
thereto in a data field (of a BB frame), and composes a
BB frame by attaching a BB header containing an ISSY to
the data field. The process then moves on to step S12.
20 [0093]
In step S12, the data processing unit 101
repeatedly distributes the BB frames constituting a BB
stream as a stream of BB frames to one data slice DS#n-1
among the three data slices DS#0 through #2, to divide
25 the BB stream into three divisional streams on a BB frame
basis.
[0094]
Of the three divisional streams, the divisional
stream obtained by distributing the BB frames to the data
30 slice DS#n-1 is supplied from the data processing unit
101 to the data slice processing unit 21n.
21
[0095]
After that, the process moves from step S12 on to
step S13. In the data slice processing unit 21n, the FEC
unit 42 performs error correction encoding on the BB
frames constituting the divisional stream 5 supplied from
the data processing unit 101 to the data slice processing
unit 21n, and supplies the resultant FEC frame to the
mapping unit 43. The process then moves on to step S14.
[0096]
10 In step S14, for each symbol formed with a
predetermined number of bits, the mapping unit 43 maps
the FEC frame supplied from the FEC unit 42 on a signal
point in a predetermined constellation, and supplies a
symbol as a mapping result to the data slice packet
15 composing unit 44 on a FEC frame basis. The process then
moves on to step S15.
[0097]
In step S15, the data slice packet composing unit
44 composes a data slice packet by attaching an FEC frame
20 header to the FEC frame supplied from the mapping unit 43,
and further supplies one or more data slice packets to
the data slice composing unit 32. The process then moves
on to step S16.
[0098]
25 In step S16, the data slice composing unit 32
composes a data slice from the one or more data slice
packets supplied from the data slice packet composing
unit 44 (and each PLP processing unit 31m not shown in
Fig. 5), and supplies the data slice to the
30 time/frequency interleaver 33. The process then moves on
to step S17.
22
[0099]
In the data slice processing units 211 through 213
shown in Fig. 5, the PLPs formed with divisional streams
supplied from the data processing unit 101 are PLPs with
the same PLP_ID. Therefore, the data slices 5 DS#0 through
DS#2 composed by the data slice processing units 211
through 213 shown in Fig. 5 contain PLPs with the same
PLP_ID.
[0100]
10 In step S17, the time/frequency interleaver 33
interleaves the data slice supplied from the data slice
composing unit 32 in the temporal direction and the
frequency direction, and supplies the interleaved data
slice to the frame composing unit 22. The process then
15 moves on to step S18.
[0101]
In step S18, the frame composing unit 22 composes a
C2 frame containing the one or more data slices supplied
from (the time/frequency interleavers 33 of) the data
20 slice processing units 211 through 21N, and supplies the
C2 frame to the IFFT unit 23. The process then moves on
to step S19.
[0102]
In step S19, the IFFT unit 23 performs IFFT on the
25 C2 frame supplied from the frame composing unit 22, and
supplies the resultant OFDM signal to the DAC 24. The
process then moves on to step S20.
[0103]
In step S20, the DAC 24 performs DA conversion on
30 the OFDM signal supplied from the IFFT unit 23, and
supplies the OFDM signal to the modulating unit 25. The
23
process then moves on to step S21.
[0104]
In step S21, the modulating unit 25 modulates the
OFDM signal supplied from the DAC 24 into an RF signal,
and transmits the RF signal via the transmission 5 channel
13 (Fig. 1).
[0105]
Fig. 7 is a diagram showing the format of a BB
frame in HEM.
10 [0106]
A BB frame (BBFrame) includes a BB header
(BBHEADER) and a data field (DATA FIELD) in which actual
data is placed.
[0107]
15 The BB header is formed with 80 bits, and has a 3-
byte field in which an ISSY is placed. The 3-byte field
in which an ISSY is placed is divided into a 2-byte field
and a 1-byte field.
[0108]
20 In the transmission device 11 (Fig. 5), the FEC
unit 42 performs BCH encoding on the BB frame, and
performs LDPC encoding on a result of the BCH encoding.
[0109]
Accordingly, the size Kbch of the data to be
25 subjected to the BCH encoding is equal to the frame
length of the BB frame. Since the BB header is formed
with 80 bits as described above, the range (the number of
bits) of the size DFL of the data field in the BB frame
is represented, with Kbch, by the expression, 0 <= DFL <=
30 Kbch - 80.
[0110]
24
The size Kbch of the data to be subjected to the
BCH encoding is the number of bits within the range
represented by the expression, 7032 <= Kbch <= 58192.
[0111]
Fig. 8 is a diagram showing the 5 formats of ISSYs
included in BB headers.
[0112]
An ISSY is an ISCR (Input Stream Time Reference), a
BUFS, or a BUFSTAT.
10 [0113]
An ISCR is time information indicating the
transmission time of data (a BB frame), and is 2- or 3-
byte information.
[0114]
15 A BUFS is (substantially) 2-byte information
indicating the buffer capacity (Required Buffer Amount)
required for compensating for delay variation in data
processing in the reception device 12.
[0115]
20 The two bits of the fifth bit and the sixth bit
counted from the top of the bit string as a BUFS formed
with two bytes (First Byte and Second Byte) are called
BUFS_UNIT, and indicate the unit of the buffer capacity
represented by the BUFS. The 10 bits formed with the
25 seventh bit through the sixteenth and last bit indicate
the value of the buffer capacity.
[0116]
In the reception device 12, a storage area as a
buffer of the buffer capacity indicated by the BUFS, and
30 delay variation is compensated for (absorbed) by data
reading/writing performed on the buffer.
25
[0117]
BUFSTAT is (substantially) 2-byte information
indicating the read start time at which data is read from
the buffer of the buffer capacity indicated by a BUFS in
the reception 5 device 12.
[0118]
The two bits of the fifth bit and the sixth bit
counted from the top of the bit string as a BUFSTAT
formed with two bytes (First Byte and Second Byte) are
10 called BUFSTAT_UNIT, and indicate the unit of the read
start time represented by the BUFSTAT. The 10 bits
formed with the seventh bit through the sixteenth and
last bit indicate the value of the read start time. The
10 bits of the BUFSTAT indicate the read start time
15 (timing) in the form of the remaining data amount in the
buffer when data is read from the buffer.
[0119]
In the reception device 12, the data stored in the
buffer of the buffer capacity indicated by a BUFS starts
20 to be read out at the time indicated by a BUFSTAT (at the
time when the remaining data amount in the buffer becomes
equal to the value indicated by the BUFSTAT).
[0120]
In a case where PLP bundling is not performed, an
25 ISCR, a BUFS, or a BUFSTAT is selectively placed in the
3-byte field of the ISSY in the BB header of each BB
frame.
[0121]
In a case where PLP bundling is performed, the ISCR
30 among an ISCR, a BUFS, and a BUFSTAT is placed in the 3-
byte field of the ISSY in the BB header of each BB frame.
26
[0122]
Fig. 9 is a diagram for explaining the relationship
between PLPs and data slices to be processed in the
transmission device 11 shown in Fig. 5.
5 [0123]
As shown in Fig. 9, in PLP bundling, PLPs with the
same PLP_ID (PLPs#0 in Fig. 9) equivalent to the actual
data of a certain television program are distributed
among data slices (the three data slices DS#0 through
10 DS#2 in Fig. 9), and are then transmitted from the
transmission device 11.
[0124]
Therefore, the reception device 12 receives the
three data slices DS#0 through DS#2 for the actual data
15 of the television program corresponding to the PLPs#0,
and needs to perform recomposition from the PLPs#0
contained in the three data slices DS#0 through DS#2.
[0125]
A unit transmission band is 6 MHz in Fig. 3, but a
20 unit transmission band is 5.72 MHz in Fig. 6. In Fig. 3,
6 MHz is equivalent to 4096 subcarriers contained in an
OFDM signal according to DVB-C2. In Fig. 6, 5.72 MHz is
equivalent 3409 subcarriers, which are the effective
subcarriers among the 4096 subcarriers.
25 [0126]
Also, in Fig. 6, only (part of) one PLP#0 is
transmitted with one data slice DS#n-1. However, with
one data slice DS#n-1, it is possible to transmit not
only one PLP#0 but also a PLP other than the PLPs#0
30 (regardless of whether these PLPs are to be subjected to
PLP bundling).
27
[0127]
[Second Example Structure of the Reception Device
12]
[0128]
Fig. 10 is a block diagram showing 5 a second example
structure of the reception device 12 shown in Fig. 1.
[0129]
In the drawing, the components equivalent to those
in Fig. 4 are denoted by the same reference numerals as
10 those used in Fig. 4, and explanation thereof is not
repeated herein.
[0130]
In the reception device 12 having the second
example structure (Fig. 10), PLPs are distributed among
15 three (or less) data slices and are transmitted (sent) by
PLP bundling, so that actual data can be recomposed, as
described above with reference to Figs. 5 and 9.
[0131]
In Fig. 10, the reception device 12 includes a
20 demodulating unit 51, an ADC 52, an FFT unit 53, a frame
decomposing unit 54, a time/frequency deinterleaver 55, a
data slice decomposing unit 56, a data slice packet
decomposing unit 57, a demapping unit 58, and an FEC unit
59. In this aspect, the reception device 12 is the same
25 as the first example structure shown in Fig. 4.
[0132]
However, the reception device 12 in Fig. 10 differs
from the first example structure shown in Fig. 4, in
further including three data slice processing units 1211,
30 1212, and 1213, for example, and three buffers 1221, 1222,
and 1223 corresponding in number to the data slice
28
processing units 1211 through 1213.
[0133]
Furthermore, the reception device 12 in Fig. 10
differs from the second example structure shown in Fig. 4,
in including a data processing unit 123, 5 instead of the
data processing unit 60.
[0134]
The data slice processing unit 1211 is formed with
the time/frequency deinterleaver 55, the data slice
10 decomposing unit 56, and a PLP processing unit 131, and
the PLP processing unit 131 is formed with the data slice
packet decomposing unit 57, the demapping unit 58, and
the FEC unit 59.
[0135]
15 The data slice processing units 1212 and 1213 each
have the same structure as the data slice processing unit
1211.
[0136]
In Fig. 10, the frame decomposing unit 54
20 decomposes a C2 frame supplied from the FFT unit 53, to
extract the three data slices DS#0, 1, and 2 contained in
the C2 frame, for example, the data slices DS#0, 1, and 2
containing PLPs with the same PLP_ID transmitted by PLP
bundling.
25 [0137]
The frame decomposing unit 54 then supplies a data
slice DS#n-1 to the data slice processing unit 121n.
[0138]
In the data slice processing unit 121n, the
30 components from the time/frequency deinterleaver 55
through the FEC unit 59 perform the same processes as
29
those in the case shown in Fig. 4 on the data slice DS#n-
1 supplied from the frame decomposing unit 54, to restore
a divisional stream formed with BB frames.
[0139]
The divisional stream restored from 5 the data slice
DS#n-1 is supplied from the data slice processing unit
121n to the buffer 122n.
[0140]
The buffer 122n is formed with an FIFO (First In
10 First Out) memory, for example, and sequentially stores
(the BB frames constituting) the divisional stream
supplied from the data slice processing unit 121n.
[0141]
The data processing unit 123 rearranges the BB
15 frames to recompose the original BB stream by reading the
BB frames from the buffer 122n in sequential order of the
BB frames constituting the original BB stream based on
the ISSYs (ISCRs) contained in the BB headers of the BB
frames constituting the three divisional streams stored
20 in the buffers 1221 through 1223.
[0142]
The data processing unit 123 further decomposes the
BB frames constituting the original BB stream, and
restores and outputs actual data.
25 [0143]
As described above, in the reception device 12, the
data processing unit 123 rearranges BB frames based on
the ISSYs contained in the BB headers of the BB frames
constituting three divisional streams. Therefore, the BB
30 frames constituting a divisional stream are stored in the
buffer 122n.
30
[0144]
The BB frames constituting the divisional stream
stored in the buffer 122n remain stored in the buffer
122n until the time according to the sequence in the
original BB stream, and is read from the 5 buffer 122n when
the time according to the sequence in the original BB
stream comes.
[0145]
Fig. 11 is a flowchart for explaining an example of
10 the process (reception process) to be performed by the
reception device 12 shown in Fig. 10 in a case where data
transmitted by PLP bundling is received.
[0146]
In step S51, the demodulating unit 51 receives and
15 demodulates an RF signal, and supplies the resultant
demodulated signal to the ADC 52. The process then moves
on to step S52.
[0147]
In step S52, the ADC 52 performs AD conversion on
20 the demodulated signal supplied from the demodulating
unit 51, and supplies the resultant digital signal to the
FFT unit 53. The process moves on to step S53.
[0148]
In step S53, the FFT unit 53 performs FFT on the
25 digital signal supplied from the ADC 52, and supplies the
resultant C2 frame to the frame decomposing unit 54. The
process then moves on to step S54.
[0149]
In step S54, the frame decomposing unit 54
30 decomposes the C2 frame supplied from the FFT unit 53, to
extract the three data slices DS#0, 1, and 2 contained in
31
the C2 frame, the data slices DS#0, 1, and 2 containing
PLPs with the same PLP_ID transmitted by PLP bundling.
The frame decomposing unit 54 supplies a data slice DS#n-
1 to the data slice processing unit 121n. The process
then moves 5 on to step S55.
[0150]
In step S55, the time/frequency deinterleaver 55 of
the data slice processing unit 121n deinterleaves the
data slice DS#n-1 supplied from the frame decomposing
10 unit 54 in the frequency direction, further deinterleaves
the data slice DS#n-1 in the temporal direction, and
supplies the deinterleaved data slice DS#n-1 to the data
slice decomposing unit 56. The process then moves on to
step S56.
15 [0151]
In step S56, the data slice decomposing unit 56
decomposes the data slice #n-1 supplied from the
time/frequency deinterleaver 55 into data slice packets,
and supplies the data slice packets to the data slice
20 packet decomposing unit 57. The process then moves on to
step S57.
[0152]
In step S57, the data slice packet decomposing unit
57 decomposes the data slice packets supplied from the
25 data slice decomposing unit 56 into FEC frames, and
supplies the FEC frames to the demapping unit 58. The
process then moves on to step S58.
[0153]
In step S58, the demapping unit 58 performs
30 demapping on (the symbols of) the FEC frames supplied
from the data slice packet decomposing unit 57, and
32
supplies the FEC frames to the FEC unit 59. The process
then moves on to step S59.
[0154]
In step S59, the FEC unit 59 performs error
correction on the damapped FEC frames 5 supplied from the
demapping unit 58, and supplies the resultant divisional
stream formed with BB frames to the buffer 122n. The
process then moves on to step S60.
[0155]
10 In step S60, the buffer 122n stores (buffers) the
BB frames of the divisional stream supplied from (the FEC
unit 59 of) the data slice processing unit 121n. The
process then moves on to step S61.
[0156]
15 In step S61, the data processing unit 123
rearranges the BB frames to recompose the original BB
stream by reading the BB frames from the buffers 1221
through 1223 as appropriate based on the ISSYs (ISCRs)
contained in the BB headers of the BB frames constituting
20 the three divisional streams stored in the buffers 1221
through 1223. The process then moves on to step S62.
[0157]
In step S62, the data processing unit 123
decomposes the BB frames constituting the original BB
25 stream, and restores and outputs actual data.
[0158]
As described above, by PLP bundling, the BB frames
of a BB stream generated from (formed with) actual data
as one PLP are distributed among data slices in the
30 transmission device 11, so that the BB stream is divided
into divisional streams on a BB frame basis, and the
33
divisional streams (PLPs with the same PLP_ID) are sent
(transmitted) with the respective data slices.
[0159]
In the reception device 12, in turn, the BB frames
in the divisional streams are rearranged 5 based on the
ISSYs contained in the BB headers, and the original BB
stream is recomposed from the divisional streams obtained
from the data transmitted from the transmission device 11.
[0160]
10 Accordingly, by PLP bundling, actual data with a
high data rate that is difficult to be transmitted with
one data slice can be transmitted with data slices.
[0161]
[BB Stream Dividing]
15 [0162]
Fig. 12 is a diagram showing an example of a method
of dividing a BB stream into divisional streams by
distributing BB frames among data slices in PLP bundling.
[0163]
20 In Fig. 12, the BB frame constituting a (original)
BB stream are distributed between two data slices DS#0
and DS#1, so that the BB stream is divided into two
divisional streams.
[0164]
25 Hereinafter, a divisional stream formed with the BB
frame distributed to a data slice DS#n-1 will be also
written as a divisional stream DS#n-1.
[0165]
Also, the jth BB frame counted from the top of a
30 (original) BB stream will be hereinafter also written as
a BB frame #j-1 (or #j).
34
[0166]
Further, for ease of explanation, in the
description below, a BB stream is distributed between the
two data slices DS#0 and DS#1, so as to be divided into
two divisional streams 5 DS#0 and DS#1.
[0167]
In Fig. 12, the four BB frames #0 through #4 from
the top of the BB stream are distributed to the data
slice DS#0, and the four BB frames #5 through #9 that
10 follow are distributed to the data slice DS#1.
Thereafter, BB frames are distributed in the same manner,
so that the BB stream is divided into the two divisional
streams DS#0 and DS#1.
[0168]
15 In DVB-C2, the details of a method of dividing a BB
stream into divisional streams in PLP bundling are not
specified.
[0169]
Therefore, as a method of dividing a BB stream, it
20 is possible to employ a method of alternately
distributing the same number, such as four, of BB frames
to the data slices DS#0 and DS#1 as shown in Fig. 12, or
a method of alternately distributing different numbers of
BB frames to the data slices DS#0 and DS#1.
25 [0170]
In the reception device 12 (Fig. 10), however, the
BB frames constituting a divisional stream DS#n-1 is
stored into the buffer 122n, and are read from the buffer
122n at the time according to the sequence in the
30 original BB stream, so as to recompose the original BB
stream.
35
[0171]
Therefore, in a case where there are no
restrictions on the method of dividing a BB stream, it is
difficult to determine the capacity of the buffer 122n
required for recomposing an original 5 BB stream in the
reception device 12.
[0172]
In this case, so as to recompose an original BB
stream, there might be a need to employ a buffer with an
10 extremely large capacity as the buffer 122n in the
reception device 12, leading to an increase in the costs
of the reception device 12.
[0173]
In view of this, the data processing unit 101 of
15 the transmission device 11 shown in Fig. 5 can limit the
data rate ratio between the data rates of divisional
streams obtained as a result of dividing of a BB stream.
[0174]
That is, the data processing unit 101 limits the
20 data rate ratio between the data rates of divisional
streams to be obtained as a result of dividing of a BB
stream to a value within a predetermined range (within a
predetermined range of ratios) so as not to cause a large
difference between the data rates of the divisional
25 streams. The data processing unit 101 then divides the
BB stream.
[0175]
In a case where the data rate ratio between the
data rates of divisional streams is not limited, a small
30 number, such as one, of BB frames is distributed to the
data slice DS#0, and a large number, such as 100, of BB
36
frames are then distributed to the data slice DS#1, for
example. This is repeated in dividing of a BB stream.
[0176]
In this case, if one BB frame is transmitted with
the data slice DS#0 and 100 BB frames 5 are transmitted
with the data slice DS#1 in a certain time T, the
reception device 12 shown in Fig. 10 needs to have
buffers with extremely different capacities from each
other as the buffer 1221 to store the divisional stream
10 DS#0 (the divisional stream formed with the BB frames
distributed to the data slice DS#0) and the buffer 1222
to store the divisional stream DS#1.
[0177]
That is, for ease of explanation, if the BB frames
15 constituting divisional frames are stored in the
reception device 12, and the BB frames are read out at
the times according to the sequence in the original BB
stream, a buffer with a small capacity to store one BB
frame to be transmitted in the time T can be employed as
20 the buffer 1221, but a buffer with a large capacity to
store 100 BB frames to be transmitted in the time T needs
to be prepared as the buffer 1222.
[0178]
In the data processing unit 101 (Fig. 5), the data
25 rate ratio between the data rates of the divisional
streams obtained as a result of dividing of a BB stream
is limited to a value within a predetermined range so as
not to cause a large difference between the data rates of
the divisional streams. With this arrangement, there is
30 no need for the buffer 1222 to have the above described
large capacity.
37
[0179]
That is, in a case where the data rate ratio
between the data rate of the divisional stream DS#0 to be
transmitted with the data slice DS#0 and the data rate of
the divisional stream DS#1 to be transmitted 5 with the
data slice DS#1 is limited to a value, such as 1 : 2,
within such a range as not to cause a large difference
between the data rates of the divisional streams DS#0 and
DS#1, the data processing unit 101 divides a BB stream by
10 repeating the process of distributing one BB frame to the
data slice DS#0 and then distributing two BB frames to
the data slice DS#1, for example.
[0180]
In this case, the reception device 12 in Fig. 10
15 does not need to have buffers with extremely different
capacities from each other as the buffer 1221 to store
the divisional stream DS#0 and the buffer 1222 to store
the divisional stream DS#1.
[0181]
20 As a result, the buffer 1222 does not need to have
a large capacity as described above, the costs of the
reception device 12 are lowered, and PLP bundling as a
kind of CB can be performed.
[0182]
25 It should be noted that the above described
limiting of the data rate ratio between the data rates of
the divisional streams obtained as a result of dividing
of a BB stream is performed in step S12 in Fig. 6 in the
data processing unit 101 (Fig. 5).
30 [0183]
In the data processing unit 101 (Fig. 5), even if
38
the data rate ratio between the data rates of the
divisional streams DS#0 and DS#1 obtained as a result of
dividing of a BB stream is limited to a value within a
predetermined range so as not to cause a large difference
between the data rates of the divisional 5 streams DS#0 and
DS#1, the buffers 1221 and 1222 might need to have large
capacities in some cases.
[0184]
That is, even if the data rate ratio between the
10 divisional streams DS#0 and DS#1 is limited to 1: 2 as
described above, for example, the buffers 1221 and 1222
might need to have large capacities in a case where the
data processing unit 101 divides a BB stream by repeating
the process of distributing a large number, such as 100,
15 of BB frames to the data slice DS#0 and then distributing
a large number, such as 200, of BB frames to the data
slice DS#1.
[0185]
In view of this, the data processing unit 101 (Fig.
20 5) can limit the number of BB frames to be
uninterruptedly distributed to one data slice in dividing
of a BB stream.
[0186]
In dividing of a BB stream, the number of BB frames
25 to be uninterruptedly distributed to one data slice is
limited to a smaller frame number than 10, for example,
so that the BB stream is not divided by uninterruptedly
distributing large numbers, such as 100 and 200, of BB
frames to the data slices DS#0 and DS#1 as described
30 above.
[0187]
39
As a result, the buffers 1221 and 1222 do not need
to have large capacities, the costs of the reception
device 12 are lowered, and PLP bundling as a kind of CB
can be performed.
5 [0188]
It should be noted that, like the limiting of the
data rate ratio between the data rates of divisional
streams, the above described limiting of the number of BB
frames to be uninterruptedly distributed to one data
10 slice is performed in step S12 in Fig. 6 in the data
processing unit 101 (Fig. 5).
[0189]
In a case where a BB stream is divided into two
divisional streams DS#0 and DS#1, if the number of BB
15 frames to be uninterruptedly distributed to one data
slice is limited to 10, the buffer capacities of the
buffers 1221 and 1222 of the reception device 12 (Fig.
10) can be determined according to the equation (1), for
example.
20 [0190]
Buffer capacity [bits] = 58192 × 10 [bits] + margin
to accommodate decoded output delay difference [bits] ...
(1)
[0191]
25 In the equation (1), 58192 is the maximum value of
the size Kbch of the data to be subjected to the BCH
encoding described above with reference to Fig. 7, or the
maximum value (number of bits) of the size of a BB frame.
[0192]
30 Also, in the equation (1), the decoded output delay
difference means (the maximum value of) a difference
40
between the times at which divisional streams are
obtained from two data slice processing units 121n and
121n in a case where the same data slice is supplied to
the two data slice processing units 121n and 121n such as
the data slice processing unit 1211 in 5 the stage before
the buffer 1221 and the data slice processing unit 1212
in the stage before the buffer 1222 in the reception
device 12 shown in Fig. 10.
[0193]
10 Meanwhile, the transmission rate at which data can
be transmitted with a data slice varies with the data
slice width and the notch width, for example.
[0194]
Therefore, in a case where a BB stream is divided
15 into two divisional streams DS#0 and DS#1, the data slice
DS#0 for transmitting (the BB frames constituting) the
divisional stream DS#0 and the data slice DS#1 for
transmitting the divisional stream DS#1 might have
different transmission rates from each other.
20 [0195]
Fig. 13 is a diagram showing an example of the
divisional streams DS#0 and #1 to be transmitted with the
data slices DS#0 and DS#1, respectively, in a case where
the transmission rate ratio between the transmission
25 rates of the data slices DS#0 and DS#1 is 2.2 : 1.
[0196]
In Fig. 13, the data rate ratio between the data
rates of the divisional streams DS#0 and DS#1 is limited
to a value within a predetermined range, so as not to
30 cause a large difference between the data rates of the
divisional streams DS#0 and DS#1.
41
[0197]
Further, in Fig. 13, the number of BB frames to be
uninterruptedly distributed to one data slice is limited
to 10, for example.
5 [0198]
In Fig. 13, the 10 BB frames #1 through #10 from
the top of the BB stream are distributed to the data
slice DS#0, and the 10 BB frames #11 through #20 that
follow are distributed to the data slice DS#1.
10 Thereafter, BB frames are distributed in the same manner,
so that the BB stream is divided into the two divisional
streams DS#0 and DS#1.
[0199]
In Fig. 13, the transmission rate ratio between the
15 data slices DS#0 and DS#1 is 2.2 : 1, and therefore, the
time required for transmission of BB frames with the data
slice DS#1 is 2.2 times as long as the time required for
transmission of BB frames with the data slice DS#0.
[0200]
20 To put it simply, when the BB frame #21 transmitted
with the data slice DS#0 is stored into the buffer 1221
in the reception device 12 shown in Fig. 10, only the BB
frames #11 through #15 transmitted with the data slice
DS#1 are already stored in the buffer 1222.
25 [0201]
When the data processing unit 123 in the reception
device 12 (Fig. 10) recomposes a BB stream, the BB frame
#21 stored in the buffer 1221 needs to be read out after
the BB frame #20 located immediately before the BB frame
30 #21 is read out.
[0202]
42
In Fig. 13, however, the BB frame #20 is
transmitted with the data slice DS#1. The BB frame #20
transmitted with the data slice DS#1 is stored into the
buffer 1222 at the same time as the BB frames #42 and #43
transmitted with the data slice DS#0 are 5 stored into the
buffer 1221. Until then, the BB frame #21 stored in the
buffer 1221 cannot be read out, and needs to remain
stored in the buffer 1221.
[0203]
10 Furthermore, at least the BB frames transmitted
with the data slice DS#0 after the BB frame #21 (at least
the BB frames #22 through #30 and #41 through #43 in Fig.
13) need to remain stored in the buffer 1221 until the BB
frame #20 is read from the buffer 1222. As a result, a
15 buffer with a large buffer capacity needs to be prepared
as the buffer 1221.
[0204]
Here, the BB frames (such as the BB frame #20
stored in the buffer 1222, hereinafter also called the
20 preceding frames) located immediately before the BB
frames stored in one of the buffers 1221 and 1222 (such
as the BB frame #21 stored in the buffer 1221) are not
stored in the other one of the buffers, as described
above. Therefore, the BB frames stored in one of the
25 buffers (such as the BB frame #21) cannot be read out,
and reading out the BB frames stored in one of the
buffers (such as the BB frame #21) needs to wait until
the preceding frames (such as the BB frame #20) are
stored into the other buffer and are read from the other
30 buffer. This is also called the waiting for BB frame
readout.
43
[0205]
At the data processing unit 101 (Fig. 5),
distribution of BB frames to data slices can be
controlled in accordance with the transmission rate ratio
between the data slices in dividing a 5 BB stream, so that
the waiting for BB frame readout is minimized.
[0206]
That is, in dividing a BB stream at the data
processing unit 101, distribution of BB frames to data
10 slices can be controlled in accordance with the
transmission rate ratio between the data slices, so that
the data rate ratio between divisional streams becomes as
close to the transmission rate ratio between the data
slices as possible.
15 [0207]
Fig. 14 is a diagram for explaining an example of
control on distribution of BB frames to the data slices
DS#0 and DS#1 in accordance with the transmission rate
ratio between the data slices DS#0 and DS#1 in a case
20 where a BB stream is divided into the divisional streams
DS#0 and #1.
[0208]
The data processing unit 101 distributes BB frames
to the data slices DS#0 and DS#1 in accordance with the
25 transmission rate ratio between the data slices DS#0 and
DS#1, so that the waiting for BB frame readout is
minimized in the reception device 12 shown in Fig. 10.
[0209]
Like Fig. 13, Fig. 14 shows an example of the
30 divisional streams DS#0 and #1 to be transmitted with the
data slices DS#0 and DS#1, respectively, in a case where
44
the transmission rate ratio between the data slices DS#0
and DS#1 is 2.2 : 1.
[0210]
In Fig. 14, the data rate ratio between the data
rates of the divisional streams DS#0 and 5 DS#1 is limited
to a value within a predetermined range as in the case
illustrated in Fig. 13, and the number of BB frames to be
uninterruptedly distributed to one data slice is limited
to 10.
10 [0211]
Further, in Fig. 14, distribution of BB frames to
the data slices DS#0 and DS#1 is controlled in accordance
with the transmission rate ratio of 2.2 : 1 between the
data slices DS#0 and DS#1, so that the waiting for BB
15 frame readout is minimized.
[0212]
That is, in Fig. 14, the 10 BB frames #1 through
#10 from the top of the BB stream are distributed to the
data slice DS#0, and the four BB frames #11 through #14
20 that follow are distributed to the data slice DS#1.
Further, in Fig. 14, the 10 BB frames #15 through #24
that follow are distributed to the data slice DS#0, and
the five BB frames #25 through #29 that follow are
distributed to the data slice DS#1.
25 [0213]
The 10 BB frames #30 through #39 that follow are
distributed to the data slice DS#0, and the four BB
frames #40 through #43 that follow are distributed to the
data slice DS#1. Thereafter, BB frames are distributed
30 in the same manner, so that the BB stream is divided into
the two divisional streams DS#0 and DS#1.
45
[0214]
In Fig. 14, the transmission rate ratio between the
data slices DS#0 and DS#1 is 2.2 : 1, and therefore, the
time required for transmission of BB frames with the data
slice DS#1 is 2.2 times as long as the 5 time required for
transmission of BB frames with the data slice DS#0, as in
Fig. 13.
[0215]
However, in Fig. 14, distribution of BB frames to
10 the data slices DS#0 and DS#1 is controlled in accordance
with the transmission rate ratio of 2.2 : 1 between the
data slices DS#0 and DS#1, so that the waiting for BB
frame readout is minimized.
[0216]
15 That is, in Fig. 14, distribution of BB frames to
the data slices DS#0 and DS#1 is controlled so that the
data rate ratio between the divisional streams DS#0 and
DS#1 becomes as close to the transmission rate ratio of
2.2 : 1 between the data slices DS#0 and DS#1 as possible,
20 for example.
[0217]
Therefore, when the BB frame #15 transmitted with
the data slice DS#0 is stored into the buffer 1221 in the
reception device 12 shown in Fig. 10, the BB frame #14
25 that is located immediately before the BB frame #15 and
is transmitted with the data slice DS#1 is already stored
in the buffer 1222.
[0218]
Accordingly, the BB frame #15 stored in the buffer
30 1221 can be read out immediately after the BB frame #14
stored in the buffer 1222 is read out.
46
[0219]
Also, in Fig. 14, when the BB frame #30 transmitted
with the data slice DS#0 is stored into the buffer 1221,
the BB frame #29 that is located immediately before the
BB frame #30 and is transmitted with the 5 data slice DS#1
is already stored in the buffer 1222.
[0220]
Accordingly, the BB frame #30 stored in the buffer
1221 can be read out immediately after the BB frame #29
10 stored in the buffer 1222 is read out.
[0221]
As described above, distribution of BB frames to
the data slices DS#0 and DS#1 is controlled in accordance
with the transmission rate ratio of 2.2 : 1 between the
15 data slices DS#0 and DS#1, so that the waiting for BB
frame readout is minimized. In this manner, the waiting
for BB frame readout is (almost) eliminated.
[0222]
As a result, the need for a buffer with a large
20 buffer capacity as the buffer 1221 (or 1222) due to the
waiting for BB frame readout can be eliminated. That is,
the costs of the reception device 12 can be lowered, and
PLP bundling as a kind of CB can be performed.
[0223]
25 It should be noted that, like the limiting of the
data rate ratio between divisional streams and the
limiting of the number of BB frames to be uninterruptedly
distributed to one data slice, the above described
control on distribution of BB frames to the data slices
30 DS#0 and DS#1 in accordance with the transmission rate
ratio between the data slices is performed in step S12 in
47
Fig. 6 in the data processing unit 101 (Fig. 5).
[0224]

5 [0225]
The above described series of processes can be
performed with hardware, and can also be performed with
software. Where the series of processes are performed
with software, the program that forms the software is
10 installed into a general-purpose computer or the like.
[0226]
In view of this, Fig. 15 shows an example structure
of an embodiment of a computer into which the program for
performing the above described series of processes is
15 installed.
[0227]
The program can be recorded beforehand in a hard
disk 205 or a ROM 203 provided as a recording medium in
the computer.
20 [0228]
Alternatively, the program can be stored (recorded)
in a removable recording medium 211. Such a removable
recording medium 211 can be provided as so-called
packaged software. Here, the removable recording medium
25 211 may be a flexible disk, a CD-ROM (Compact Disc Read
Only Memory), an MO (Magneto Optical) disk, a DVD(Digital
Versatile Disc), a magnetic disk, or a semiconductor
memory, for example.
[0229]
30 The program can be installed into the computer from
the above described removable recording medium 211, but
48
can also be downloaded into the computer via a
communication network or a broadcasting network and be
installed into the internal hard disk 205. That is, the
program can be wirelessly transferred from a download
site, for example, to the computer 5 via an artificial
satellite for digital satellite broadcasting, or can be
transferred by cable to the computer via a network such
as a LAN (Local Area Network) or the Internet.
[0230]
10 The computer includes a CPU (Central Processing
Unit) 202, and an input/output interface 210 is connected
to the CPU 202 via a bus 201.
[0231]
When an instruction is input by a user operating an
15 input unit 207 or the like via the input/output interface
210, the CPU 202 executes the program stored in the ROM
(Read Only Memory) 203 in accordance with the instruction.
Alternatively, the CPU 202 loads the program stored in
the hard disk 205 into a RAM (Random Access Memory) 204,
20 and executes the program.
[0232]
By doing so, the CPU 202 performs the processes
according to the above described flowcharts, or performs
the processes with the structures illustrated in the
25 above described block diagrams. Where necessary, the CPU
202 outputs the process results from an output unit 206
or transmit the process results from a communication unit
208, via the input/output interface 210, for example, and
further stores the process results into the hard disk 205.
30 [0233]
The input unit 207 is formed with a keyboard, a
49
mouse, a microphone, and the like. The output unit 206
is formed with an LCD (Liquid Crystal Display), a speaker,
and the like.
[0234]
In this specification, the processes 5 performed by
the computer in accordance with the program are not
necessarily performed in chronological order compliant
with the sequences shown in the flowcharts. That is, the
processes to be performed by the computer in accordance
10 with the program include processes to be performed in
parallel or independently of one another (such as
parallel processes or object-based processes).
[0235]
The program may be executed by one computer
15 (processor), or may be executed in a distributive manner
by more than one computer. Further, the program may be
transferred to a remote computer, and be executed therein.
[0236]
In this specification, a system means an assembly
20 of components (devices, modules (parts), and the like),
and not all the components need to be provided in the
same housing. In view of this, devices that are housed
in different housings and are connected to each other via
a network form a system, and one device having modules
25 housed in one housing is also a system.
[0237]
It should be noted that embodiments of the present
technology are not limited to the above described
embodiments, and various modifications may be made to
30 them without departing from the scope of the present
technology.
50
[0238]
For example, the present technology can be embodied
in a cloud computing structure in which one function is
shared among devices via a network, and processing is
performed by the devices cooperating 5 with one another.
[0239]
The respective steps described with reference to
the above described flowcharts can be carried out by one
device or can be shared among devices.
10 [0240]
In a case where more than one process is included
in one step, the processes included in the step can be
performed by one device or can be shared among devices.
[0241]
15 The advantageous effects described in this
specification are merely examples, and the advantageous
effects of the present technology are not limited to them
and may include other effects.
[0242]
20 The present technology may also be embodied in the
structures described below.
[0243]
<1>
A data processing device including
25 a dividing unit that divides a BB stream as a
stream of BB (Baseband) frames into divisional streams by
distributing the BB frames of the BB stream to data
slices,
wherein the dividing unit divides the BB stream by
30 limiting the data rate ratio between the data rates of
the divisional streams.
51
<2>
The data processing device of <1>, wherein the
dividing unit divides the BB stream by limiting the
number of BB frames to be uninterruptedly distributed to
one of 5 the data slices.
<3>
The data processing device of <1> or <2>, wherein
the dividing unit controls the distribution of the BB
frames to the data slices in accordance with the
10 transmission rate ratio between the transmission rates at
which data can be transmitted with the data slices.
<4>
A data processing method including
the step of dividing a BB stream as a stream of BB
15 (Baseband) frames into divisional streams by distributing
the BB frames of the BB stream to data slices,
wherein the dividing of the BB stream is performed
by limiting the data rate ratio between the data rates of
the divisional streams.
20 <5>
A data processing device including
a recomposing unit that recomposes an original BB
stream as a stream of BB (Baseband) frames from
divisional streams transmitted from a transmission device,
25 the transmission device including a dividing unit
that divides the BB stream into the divisional streams by
distributing the BB frames of the BB stream to data
slices,
the dividing unit dividing the BB stream by
30 limiting the data rate ratio between the data rates of
the divisional streams.
52
<6>
The data processing device of <5>, wherein the
dividing of the BB frame is performed by limiting the
number of BB frames to be uninterruptedly distributed to
one of 5 the data slices.
<7>
The data processing device of <5> or <6>, wherein
the distribution of the BB frames to the data slices is
performed in accordance with the transmission rate ratio
10 between the transmission rates at which data can be
transmitted with the data slices.
<8>
A data processing method including
the step of recomposing an original BB stream as a
15 stream of BB (Baseband) frames from divisional streams
transmitted from a transmission device,
the transmission device including a dividing unit
that divides the BB stream into the divisional streams by
distributing the BB frames of the BB stream to data
20 slices,
the dividing unit dividing the BB stream by
limiting the data rate ratio between the data rates of
the divisional streams.
25 REFERENCE SIGNS LIST
[0244]
11 Transmission device
12 Reception device
13 Transmission channel
30 211 through 21N Data slice processing unit
22 Frame composing unit
53
23 IFFT unit
24 DAC
25 Modulating unit
311 through 31M PLP processing unit
32 Data slice 5 composing unit
33 Time/frequency interleaver
41 Data processing unit
42 FEC unit
43 Mapping unit
10 44 Data slice packet composing unit
51 Demodulating unit
52 ADC
53 FFT unit
54 Frame decomposing unit
15 55 Time/frequency deinterleaver
56 Data slice decomposing unit
57 Data slice packet decomposing unit
58 Demapping unit
59 FEC unit
20 60 Data processing unit
101 Data processing unit
111 PLP processing unit
1211 through 1213 Data slice processing unit
1221 through 1223 Buffer
25 123 Data processing unit
131 PLP processing unit
201 Bus
202 CPU
203 ROM
30 204 RAM
205 Hard Disk
54
206 Output unit
207 Input unit
208 Communication unit
209 Drive
210 Input/5 output interface
211 Removable recording medium
Dated this 11th day of August, 2015
10 MAYANK SOOD
OF K&S PARTNERS
ATTORNEY FOR THE APPLICANT(S)
1
SP356852WO00
CLAIMS
1. A data processing device comprising
a dividing unit configured to divide a BB stream as
5 a stream of BB (Baseband) frames into a plurality of
divisional streams by distributing the BB frames of the
BB stream to a plurality of data slices,
wherein the dividing unit divides the BB stream by
limiting a data rate ratio between data rates of the
10 divisional streams.
2. The data processing device according to claim 1,
wherein the dividing unit divides the BB stream by
limiting the number of BB frames to be uninterruptedly
15 distributed to one of the data slices.
3. The data processing device according to claim 2,
wherein the dividing unit controls the distribution of
the BB frames to the data slices in accordance with a
20 transmission rate ratio between transmission rates at
which data can be transmitted with the data slices.
4. A data processing method comprising
the step of dividing a BB stream as a stream of BB
25 (Baseband) frames into a plurality of divisional streams
by distributing the BB frames of the BB stream to a
plurality of data slices,
wherein the dividing of the BB stream is performed
by limiting a data rate ratio between data rates of the
30 divisional streams.
2
SP356852WO00
5. (amended) A data processing device comprising
a recomposing unit configured to recompose an
original BB stream as a stream of BB (Baseband) frames
from a plurality of divisional streams transmitted from a
5 transmission device, a data rate ratio between the
divisional streams being limited,
the transmission device including a dividing unit
configured to divide the BB stream into the divisional
streams by distributing the BB frames of the BB stream to
10 a plurality of data slices,
the dividing unit dividing the BB stream by
limiting the data rate ratio between data rates of the
divisional streams.
15 6. The data processing device according to claim 5,
wherein the dividing of the BB frame is performed by
limiting the number of BB frames to be uninterruptedly
distributed to one of the data slices.
20 7. The data processing device according to claim 6,
wherein the distribution of the BB frames to the data
slices is performed in accordance with a transmission
rate ratio between transmission rates at which data can
be transmitted with the data slices.
25
8. (amended) A data processing method comprising
the step of recomposing an original BB stream as a
stream of BB (Baseband) frames from a plurality of
divisional streams transmitted from a transmission device,
30 a data rate ratio between the divisional streams being
limited,
3
SP356852WO00
the transmission device including a dividing unit
configured to divide the BB stream into the divisional
streams by distributing the BB frames of the BB stream to
a plurality of data slices,
5 the dividing unit dividing the BB stream by
limiting the data rate ratio between data rates of the
divisional streams.