Note: Descriptions are shown in the official language in which they were submitted.
TRANSMITTING APPARATUS AND RECEIVING APPARATUS AND SIGNAL
PROCESSING METHOD THEREOF
This application is a divisional of Canadian patent application Serial No.
2,972,882 filed
internationally on January 7, 2016 and entered nationally on June 30, 2017.
Technical Field
[1] Apparatuses and methods consistent with the exemplary embodiments
relate to a
transmitting apparatus and a receiving apparatus and a signal processing
method thereof, and more
particularly, to a transmitting apparatus which transmits data by mapping the
data to at least one
signal processing path and a receiving apparatus and a signal processing
method thereof.
Background Art
[2] In the information-oriented society of the 21st century, broadcasting
communication
services are entering the era of digitization, multi-channel, broadband, and
high quality. In
particular, as high-quality digital television (TV), portable multimedia
player (PMP), and portable
broadcasting apparatuses have been increasingly used in recent years, there is
an increasing
demand for digital broadcasting services that are able to support various
receiving methods.
Further, there is also an increasing demand for data transmission of various
pockets constituted by
a moving picture experts group (MPEG)2-transport stream (TS) packet which is
traditionally used
through a broadcasting network and an Internet protocol based packet.
[3] Thus, the broadcasting communication standard group has established
various standards
according to the demand to provide various services to satisfy user's needs.
Still, however, a
method for providing better broadcasting communication services with more
excellent
performance by using universal data is required.
Disclosure of Invention
Technical Problem
[4] Exemplary embodiments of the inventive concept may overcome the above
disadvantages
and other disadvantages not described above. However, the exemplary
embodiments are not
required to overcome the disadvantages described above, and may not overcome
any of the
problems described above.
[5] The present invention has been made to solve the problems according to
the necessity,
and the present invention is purposed to provide a transmitter which generates
a packet having a
format suitable for transmitting TS packet type data, a receiver, and a signal
processing method
thereof.
Solution to Problem
1
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[6] According to an aspect of an exemplary embodiment, there is provided
a transmitting
apparatus which may include: a packet generator generating a packet including
a
header and a payload from an input stream including a plurality of transport
stream
(TS) packets; and a signal processor signal-processing the packet, wherein the
header
includes a base header including a first field indicating a packet type which
is the TS
packets, and a second field indicating a number of TS packets included in the
payload,
wherein the base header further includes a third field set to a first value
indicating that
there is no additional header or a second value indicating that there is an
additional
header, wherein, when the third field is set to the second value, the
additional header
includes a fourth field indicating a number of deleted null packets with
respect to each
of at least one TS packet group including consecutive TS packets, and wherein
the null
packets deleted with respect to each of the TS packet group precede a first TS
packet
or follow a last TS packet included in each of the TS packet group.
171 According to an aspect of another exemplary embodiment, there is
provided a signal
processing method of a transmitting apparatus. The method may include:
generating a
packet comprising a header and a payload from an input stream comprising a
plurality
of transport stream (TS) packets; and signal-processing the generated packet,
wherein
the header includes a base header including a first field indicating a packet
type which
is the TS packets, and a second field indicating a number of TS packets
included in the
payload, wherein the base header further includes a third field set to a first
value in-
dicating that there is no additional header or a second value indicating that
there is an
additional header, wherein, when the third field is set to the second value,
the ad-
ditional header includes a fourth field indicating a number of deleted null
packets with
respect to each of at least one TS packet group including consecutive TS
packets, and
wherein the null packets deleted with respect to each of the TS packet group
precede a
first TS packet or follow a last TS packet included in each of the TS packet
group.
[81
Advantageous Effects of Invention
[9] According to various exemplary embodiments, since an input stream can
be ef-
ficiently mapped to a physical layer, data processing efficiency can be
improved.
[10] Additional and/or other aspects and advantages of the inventive
concept will be set
forth in part in the description which follows and, in part, will be obvious
from the de-
scription, or may be learned by practice of the presented embodiments.
Brief Description of Drawings
[111 The above and/or other aspects of the inventive concept will be more
apparent by de-
scribing certain exemplary embodiments with reference to the accompanying
drawings, in which:
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[12] FIG. 1 is a diagram illustrating a hierarchical structure of a
transmitting system
according to an exemplary embodiment;
[13] FIG. 2 is a diagram illustrating a schematic configuration of a
broadcasting link layer
according to the exemplary embodiment;
[14] FIG. 3A is a diagram illustrating a schematic configuration of a
transmitting system
(alternatively, a transmitting apparatus) according to an exemplary
embodiment;
[15] FIGs. 3B and 3C are diagrams illustrating a multiplexing method
according to
exemplary embodiments;
[16] FIGs. 4 to 5B are block diagrams illustrating a detailed configuration
of an input
forinatting block illustrated in FIG. 3A, according to an exemplary
embodiment;
[17] FIG. 6 is a block diagram illustrating a configuration of a
transmitting apparatus
according to an exemplary embodiment;
[18] FIG. 7 is a diagram illustrating an ATSC 3.0 link-layer protocol (ALP)
packet
structure according to an exemplary embodiment;
[19] FIG. 8 is a diagram illustrating a structure of a base header of an
ALP packet
according to an exemplary embodiment;
[20] FIG. 9 is a diagram for describing a null packet deletion mechanism
according to an
exemplary embodiment;
[21] FIG. 10 is a diagram for describing a transport stream (TS) header
deletion
mechanism according to an exemplary embodiment;
[22] FIG. 11 is a block diagram illustrating a configuration of a
transmitting apparatus
according to another exemplary embodiment;
[23] FIG. 12 is a block diagram illustrating a detailed configuration of a
frame generator
according to an exemplary embodiment;
[24] FIG. 13 is a diagram illustrating an ALP packet, a baseband packet,
and a scrambled
baseband packet according to an exemplary embodiment;
[25] FIG. 14 is a diagram for describing a TS packet encapsulation
mechanism according
to an exemplary embodiment;
[26] FIG. 15 is a diagram for describing a TS packet encapsulation
mechanism according
to another exemplary embodiment;
[27] FIG. 16 is a diagram for describing a decapsulation mechanism of an
ALP packet il-
lustrated in FIG. 15, according to an exemplary embodiment;
[28] FIG. 17 is a diagram for describing TS packet encapsulation and a TS
header
deletion mechanism according to yet another exemplary embodiment;
[29] FIG. 18 is a diagram for describing decapsulation and TS header
restoration
mechanisms of an ALP packet illustrated in FIG. 17;
[30] FIG. 19 is a flowchart for describing a signal processing method of a
transmitting
apparatus according to an exemplary embodiment;
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[31] FIG. 20A is a block diagram illustrating a configuration of a
receiving apparatus
according to an exemplary embodiment;
[32] FIG. 20B is a block diagram illustrating a signal processor according
to an exemplary
embodiment in detail;
[33] FIG. 21 is a block diagram illustrating a configuration of a receiver
according to an
exemplary embodiment;
[34] FIG. 22 is a block diagram illustrating a demodulator of FIG. 21
according to an
exemplary embodiment in more detail;
[35] FIG. 23 is a flowchart schematically illustrating an operation of a
receiver from the
time when a user selects a service up to the time when the selected service is
actually
reproduced, according to an exemplary embodiment;
1361 FIG. 24A is a block diagram illustrating a configuration of a
receiving apparatus
according to an exemplary embodiment;
[37] FIG. 24B is a block diagram illustrating a signal processor according
to an exemplary
embodiment in detail;
[38] FIG. 25 is a block diagram illustrating a configuration of a receiver
according to an
exemplary embodiment;
[39] FIG. 26 is a block diagram illustrating the demodulator illustrated in
FIG. 25
according to an exemplary embodiment in more detail; and
[40] FIG. 27 is a flowchart schematically illustrating an operation of a
receiver from the
time when a user selects a service up to the time when the selected service is
actually
reproduced according to an exemplary embodiment.
Best Mode for Carrying out the Invention
[41]
Mode for the Invention
[42] Hereinafter, exemplary embodiments of the inventive concept will be
described in
detail with reference to the accompanying drawings.
[43] An apparatus and a method proposed in the exemplary embodiments can be
applied
to various communication systems including mobile broadcasting services
including a
digital multimedia broadcasting (DMB), (hereinafter, referred to as `DMB')
service,
digital video broadcasting handheld (DVP-H) (hereinafter, referred to as `DVP-
H'), an
advanced television systems committee mobile/handheld (ATSC-M/H) (hereinafter,
referred to as `ATSC-M/H') service, an Internet protocol television (IPTV)
service
(hereinafter, referred to as `IPTV') service, and the like, communication
systems
including a moving picture experts group (MPEG) media transport (MMT)
(hereinafter, referred to as `MMT') system, an evolved packet system (EPS)
(hereinafter, referred to as `EPS'), a long-terms evolution (LTE)
(hereinafter, referred
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to as `LTE') mobile communication system, a long-term evolution-advanced (LTE-
A)
(hereinafter, refened to as `LTE-A') mobile communication system, a high speed
downlink packet access (HDSPA) (hereinafter, referred to as `HSDPA') mobile
com-
munication system, a high speed uplink packet access (HSUPA) (hereinafter,
referred
to as `FISUPA') mobile communication system, a 3rd generation project
partnership 2
(3GPP2) (hereinafter, referred to as `3GPP2') high rate packet data (HRPD)
(hereinafter, referred to as `HRPD') mobile communication system, a 3GPP2
widcband code division multiple access (WCDMA) (hereinafter, referred to as
`WCDMA') mobile communication system, a 3GPP2 code division multiple access
(CDMA) (hereinafter, referred to as `CDMA') mobile communication system, an
Institute of Electrical and Electronics Engineers (IEEE) (hereinafter,
referred to as
'IEEE') 802.16m communication system, a mobile Internet protocol (Mobile IP)
(hereinafter, referred to as 'Mobile IP') system, and the like.
[44] FIG. 1 is a diagram illustrating a hierarchical structure of a
transmitting system
according to an exemplary embodiment.
[45] Referring to FIG. 1, a service includes media data 1000 and signaling
1050 for
transferring information required for a receiver to receive and consume the
media data.
The media data may be encapsulated in a format suitable for transmission prior
to the
transmission. An encapsulation method may follow a Media Processing Unit (MPU)
defined in ISO/IEC 23008-1 MPEG MMT or a Dynamic Adaptive Streaming over
HTTP (DASH) segment format defined in ISO/IEC 23009-1 DASH. The media data
1000 and the signaling 1050 arc packetized based on an application layer
protocol.
[46] FIG. 1 illustrates a case in which an MMT protocol (MMTP) 1110 defined
in the
MMT and a Real-Time Object Delivery over Unidirectional Transport (ROUTE)
protocol 1120 are used as the application layer protocol. In this case, a
method for
notifying information about an application layer protocol in which the service
is
transmitted independently from the application layer protocol is required for
the
receiver to know which application layer protocol a specific service is
transmitted by.
[47] A service list table (SLT) 1150 illustrated in FIG. 1 constitutes
information about the
service by a table and packetizes the information in a signaling method for
satisfying
the aforementioned object. Detailed contents of the SLT will be described
below. The
packetized media data and the signaling including the SLT are transferred to
the
broadcasting link layer 1400 through a user datagram protocol (UDP) 1200 and
an
Internet protocol (IF) 1300. An example of the broadcasting link layer
includes an
ATSC 3.0 link-layer protocol (ALP) defined in ATSC 3Ø The ALP generates an
ALP
packet by using an IP packet as an input, and transfers the ALP packet to a
broadcasting physical layer 1500.
[48] However, according to FIG. 2 to be described below, it is noted that
the broadcasting
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link layer 1400 does not use only the IP packet 1300 including the media data
andJor
the signaling as the input, and instead, may use an MPEG2-TS packet or general
formatted packetized data as the input. In this case, signaling information
required to
control the broadcasting link layer is also transferred to the broadcasting
physical layer
1500 in the form of the ALP packet.
[49] The broadcasting physical layer 1500 generates a physical layer frame
by signal-
processing the ALP packet as the input, converts the physical layer frame into
a radio
frequency (RF) signal, and transmits the RF signal. In this case, the
broadcasting
physical layer 1500 has at least one signal processing path. An example of the
signal
processing path may include a physical layer pipe (PLP) of DVB-T2 or ATSC 3.0,
and
entirety of one or more services or some of the services may be mapped to the
PLP.
1501 FIG. 2 is a diagram illustrating a schematic configuration of a
broadcasting link layer
1400 according to an exemplary embodiment.
[51] Referring to FIG. 2, the input of the broadcasting link layer 1400
includes the IP
packet 1300, and may further include a link layer signaling 1310, an MPEG2-TS
packet 1320, and other packetized data 1330.
[52] Input data may be subjected to additional signal processing based on
the type of the
input data before ALP packetization 1450. As an example of the additional
signal
processing, the IP packet 1300 may be subjected to an IP header deletion
process 1410,
and the MPEG2-TS packet may be subjected to a header reducing (or overhead
reduction) process 1420. During the ALP packetization, input packets may be
subjected to dividing and merging processes.
[53] FIG. 3A is a diagram illustrating a schematic configuration of a
transmitting system
or apparatus according to an exemplary embodiment. According to FIG. 3A, a
transmitting system 10000 according to the exemplary embodiment may include
input
formatting blocks (alternatively, parts) 11000 and 11000-1, bit interleaved
and coded
modulation (BICM) blocks 12000 and 12000-1, framing/interleaving blocks 13000
and
13000-1, and waveform generation blocks 14000 and 14000-1.
[54] The input formatting blocks 11000 and 11000-1 generate a bascband
packet from an
input stream which includes data to be serviced. Here, the input stream may be
at least
one of a transport stream (TS), an IP packet (e.g., IPv4 and IPv6), an MMT
stream, a
generic stream (GS), a generic stream encapsulation (GSE), and the like. For
example,
an ALP packet may be generated from the input stream, and the baseband packet
may
be generated from the ALP packet.
[55] The BICM blocks 12000 and 12000-1 determine a forward error correction
(FEC)
coding rate and a constellation order according to an area (fixed PHY frame or
mobile
PHY frame) through which the data to be serviced will be transmitted, and
perform
encoding and time interleaving on the encoded data. Meanwhile, a signaling
signal
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(also referred to as signaling information) for the data to be serviced may be
encoded
through a separate BICM encoder according to a system implementation or
encoded by
a same BICM encoder which decodes the data to be serviced.
156] The framing/interleaving blocks 13000 and 13000-1 combine the time-
interleaved
data with the signaling signal to generate a transmission frame.
[57] The waveform generation blocks 14000 and 14000-1 generate an
orthogonal
frequency-division multiplexing (OFDM) signal in a time domain from the
generated
transmission frame, modulate the generated OFDM signal into an RF signal, and
transmit the RF signal to a receiver.
[58] The transmitting system 10000 according to the exemplary embodiment
illustrated in
FIG. 3A includes normative blocks marked with a solid line and informative
blocks
marked with dotted lines. Here, the blocks marked with the solid line are
normal
blocks, and the blocks marked with the dotted lines are blocks which may be
used
when an informative multiple-input and multiple-output (MIMO) system is im-
plemented.
[59] FIGs. 3B and 3C are diagrams illustrating a multiplexing method
according to
exemplary embodiments.
[60] FIG. 3B illustrates a block diagram for implementing time division
multiplexing
(TDM) according to an exemplary embodiment.
[61] In a TDM system architecture, four main blocks of the input formatting
block 11000,
the BICM block 12000, the framing/interleaving block 13000, and the waveform
generation block 14000 arc present.
[62] Data is input to the input formatting block 11000 and formatted
therein. Next, FEC is
applied to the data and the data is mapped to a constellation in the BICM
block 12000.
Subsequently, the data is time and frequency-interleaved and the frame is
generated in
the framing/interleaving block 13000. Thereafter, an output waveform is
generated in
the waveform generation block 14000.
[63] FIG. 3C illustrates a block diagram for implementing layered division
multiplexing
(LDM) according to an exemplary embodiment.
[64] In an LDM system architecture, several other blocks are present as
compared with
the TDM system architecture. In detail, two separated input formatting blocks
11000
and 11000-1 and the BCIM blocks 12000 and 12000-1 for one of respective layers
of
the LDM are included in the LDM system architecture. The blocks are combined
in an
LDM injection block before the framing/interleaving block 13000. And, the
waveform
generation block 14000 is similar to the TDM.
[65] FIG. 4 is a block diagram illustrating a detailed configuration of the
input formatting
block illustrated in FIG. 3A, according to an exemplary embodiment.
[66] As illustrated in FIG. 4, the input formatting block 11000 includes
three blocks that
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control packets to be formatted and distributed to PLPs. In detail, the input
formatting
block 11000 includes an encapsulation and compression block 11100, a baseband
formatting block (alternatively, referred to as a baseband framing block)
11300, and a
scheduler block 11200.
[67] An input stream input into the encapsulation and compression block
11100 may be
constituted by various types. For example, the input stream may be at least
one of a
TS, an IP packets (e.g., IPv4 and IPv6), an MMT stream, a GS, a GSE, and the
like.
[68] Packets output from the encapsulation and compression block 11100
become ALP
packets which are generic packets, and alternatively referred to as a layer 2
(L2)
packets. Herein, a format of the ALP packet may be one of a Type Length Value
(TLV), the GSE, and the ALP.
1691 The length of each ALP packet is variable. The length of the ALP
packet may be
easily extracted from the ALP packet itself without additional information.
The
maximum length of the ALP packet is 64 kB. The maximum length of a header of
the
ALP packet may be 4 bytes. The ALP packet has a length of integer bytes.
[70] The scheduler block 11200 receives an input stream including the
encapsulated ALP
packets to form physical layer pipes (PLPs) in a baseband packet form. In the
TDM
system, only one PLP called a single PLP (S-PLP) or multiple PLPs (M-PLP) may
be
used. One service may not use four or more PLPs. In the LDM system constituted
by
two layers, one in each layer, that is, two PLPs are used.
[71] The scheduler block 11200 receives the encapsulated ALP packets to
designate how
the encapsulated ALP packets are allocated to physical layer resources. In
detail, the
scheduler block 11200 designates how the baseband formatting block 1130
outputs a
baseband packet.
[72] A function of the scheduler block 11200 is defined by a data size and
a time. A
physical layer may transmit some of data in the distributed time. The
scheduler block
generates a solution which is suitable in terms of a configuration of a
physical layer
parameter by using inputs and information such as constraints and
configuration from
an encapsulated data packet, the quality of service mctadata for the
encapsulated data
packet, a system buffer model, and system management. The solution is targets
of a
configuration and a control parameter which are usable and an aggregate
spectrum.
[73] Meanwhile, an operation of the scheduler block 11200 is constrained to
a set of
dynamic, quasi-static, and static components. Definition of the constraint may
vary
according to a system design.
[74] Further, a maximum of four PLPs may be used with respect to each
service. A
plurality of services which include a plurality of types of interleaving
blocks may be
implemented by up to a maximum of 64 PLPs with respect to a bandwidth of 6, 7,
or 8
MHz.
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[75] The baseband formatting block 11300 includes baseband packet
construction blocks
3100, 3100-1, ..., 3100-n, baseband packet header construction blocks 3200,
3200-1,
..., 3200-n, and baseband packet scrambling blocks 3300, 3300-1, ..., 3300-n,
as il-
lustrated in FIG. 5A. In an M-PLP operation, the baseband formatting block
generates
a plurality of PLPs as necessary.
1761 The baseband packet construction blocks 3100, 3100-1, ..., 3100-n
construct
baseband packets. Each baseband packet 3500 includes a header 3500-1 and a
payload
3500-2 as illustrated in FIG. 5B. A baseband packet is fixed to a length
Kpayload. ALP
packets 3610 to 3650 are sequentially mapped to a baseband packet 3500. When
the
ALP packets 3610 to 3650 do not completely fit in the baseband packet 3500,
these
packets are distributed between a current baseband packet and a next baseband
packet.
The ALP packets are distributed in a unit of a byte.
[77] The baseband packet header construction blocks 3200, 3200-1, ..., 3200-
n construct a
header 3500-1. The header 3500-1 includes three parts, that is, a base field
(also
referred to as, a base header) 3710, an optional field (also referred to as,
an option
header) 3720, and an extension field (also referred to as, an extension
header) 3730, as
illustrated in FIG. 5B. Here, the base field 3710 is shown in every baseband
packet and
the optional field 3720 and the extension field 3730 may not be shown in every
baseband packet.
[78] A main function of the base field 3710 provides a pointer of an offset
value as bytes
to indicate a start of a next ALP packet in a baseband packet. When an ALP
packet
starts a baseband packet, the value of the pointer becomes 0. When there is no
ALP
packet that starts in the baseband packet, the value of the pointer may be
8191 and a
base header of 2 bytes may be used.
[79] The extension field 3730 may be used afterwards and, for example, used
for a
baseband packet counter, baseband packet time stamping, additional signaling,
and the
like.
[80] The baseband packet scrambling blocks 3300, 3300-1, ..., 3000-n
scramble the
baseband packet.
[81] Like a case in which payload data mapped to a constellation is
configured by a
repetitive sequence, the payload data is continuously scrambled before
direction error
correction encoding so as to prevent continuous mapping to the same point.
[82] FIG. 6 is a block diagram illustrating a configuration of a
transmitting apparatus
according to an exemplary embodiment of the present disclosure.
[83] Referring to FIG. 6, the transmitting apparatus 100 includes a packet
generator 110
and a signal processor 120.
[84] The packet generator 110 may encapsulate an IP packet, a TS packet,
and various
types of data to generate packets and transmit these packets to respective
PLPs. Here,
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the packets correspond to L2 packets in an ISO 7 layer model.
[85] In detail, the packet generator 110 may generate a packet including a
header and a
payload (also referred to as a data payload), for example, an ALP packet (also
referred
to as a generic packet or an L2 packet) from an input stream. Here, the header
may
include information on the payload included in a corresponding packet and
information
on a packet included in the corresponding packet. Hereinafter, the packet
generated by
the packet generator 110 will be referred to as the ALP packet for easy
description.
[86] In general, the payload of the ALP packet may include at least one of
an IP packet, a
TS packet, and a signaling packet. Data included in the payload is not limited
to a
particular example and the payload may include various types of data including
media
data. Here, the ALP packet may be regarded as a unit packet required for
mapping
various types of data to the physical layer.
[87] As described later in detail in reference to FIGs. 7 and 8A, the ALP
packet may
include a header formed of a base header, an additional header and an optional
header.
The base header may include first to third fields. The first field may
represent a packet
type of an input stream, and when the first field is set to a value indicating
that the
packet type of the input stream is a TS packet, the second field may indicate
the
number of TS packets included in the payload, and a third field may be set to
a first
value indicating that there is no additional header or a second value
indicating that
there is an additional header.
[88] Further, when the third field is set to the second value, the
additional header may
include a fourth field indicating the number of deleted null packets with
respect to each
of at least one TS packet group constituted by consecutive TS packets. Here,
the null
packets deleted with respect to each TS packet group may be null TS packet
which im-
mediately precedes the first TS packet included in each TS packet group among
a
plurality of packets included in the input stream. According to an exemplary
em-
bodiment, however, the null packets deleted with respect to each TS packet
group may
be null TS packet which immediately follows the last TS packet included in
each TS
packet group among a plurality of packets included in the input stream. When
the
number of TS packet groups included in the payload of the ALP packet is one,
the
fourth field may include only the number of deleted null TS packets in this
single TS
group.
[89] Meanwhile, the third field may be set to the second value when there
is a deleted null
TS packet or when TS header (alternatively referred to as TS packet header)
com-
pression is applied.
[90] Further, when the third field is set to the second value, the
additional header may
include a fifth field indicating whether the TS header compression is applied.
191.I Herein, the fourth field is implemented by a 7-bit field, and when
the fifth field is set
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to a fourth value indicating that the TS header compression is not applied,
the fourth
field may be set to 0 in the case where 128 null packets are deleted. Further,
when the
fifth field is set to a fifth value indicating that the TS header compression
is applied,
the fourth field may be set to 0 when no TS null packet is deleted.
[92] The signal processor 120 may signal-process the ALP packet generated
by the packet
generator 110. Here, the signal processor 130 may perform all signal
processing
processes after the generation of the ALP packet and for example, perform all
signal
processing processes of the generation of a baseband packet to the generation
of a
transmission frame.
[93] FIG. 7 is a diagram illustrating an ALP packet structure according to
an exemplary
embodiment.
1941 Referring to FIG. 7, an ALP packet includes a header 7100 and a
payload 7200. The
header 7100 may include a base header 7110, an additional header 7120 and an
option
header 7130. The ALP packet header 7100 always includes the base header 7110,
and
whether the additional head 7120 is present in the header 7100 may vary
depending on
a control field value of the base header 7110. Further, whether the option
header 7130
is present may be selected by using a control field of the additional header
7130.
[95] FIG. 8A is a diagram illustrating a header structure of an ALP packet
according to an
exemplary embodiment.
[96] A Packet_Type field 7111 corresponds to the first field of the base
header 7110 as
described above, and is a 3-bit field indicating a protocol applied to the
input packet or
a packet type of the input packet before encapsulation into the ALP packet. As
one
example, the Packet_Type field 7111 may be encoded according to Table 1 given
below.
[97] Table 1
[Table 1]
Packet_Type Value Meaning
000 IPv4 packet
001 Reserved
010 Compressed IP packet
011 Reserved
100 Link layer signaling packet
101 Reserved
110 Packet Type Extension
111 MPEG-2 Transport Stream
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[98] When the Packet_Type field 7111 is set to a value "111" indicating an
MPEG-2 TS
packet, the base header 7110 includes a Number of TS packets (NUMTS) field
7112.
Here, the base header 7110 also includes an Additional Header Flag (AHF) field
7113.
That is, the header structure of the ALP packet illustrated in FIG. 8A is a
header
structure when the input stream is the MPEG-2 TS packet.
[99] A Number of TS packets (NUMTS) field 7112 corresponds to the second
field of the
base header 7110 as described above, and is a 4-bit field indicating the
number of TS
packets included in the payload of the ALP packet. NUMTS =`0' may indicate
that 16
packets are transmitted in the payload of the ALP packet, and NUMTS of all
other
values may indicate TS packets of the same number, i.e., the same values. For
example, NUMTS = '0001' indicates that one TS packet is transmitted. However,
according to another implementation example, NUMT = k may indicate that k + 1
TS
packets are transmitted in the payload of the ALP packet.
[100] An Additional Header Flag (AHF) field 7113 corresponds to the third
field of the
base header 7110 as described above, and is a 1-bit field indicating whether
the ad-
ditional header is present. A value "0" indicates that the additional header
is not
present and a value "1" that the additional header 7120 is present after the
base header
7110. Here, the additional header may be implemented by 1 byte. The AHF field
7113
may be set to the value "1" when the null TS packet is deleted or when the TS
header
deletion is applied. That is, the additional header 7120 for the TS packet
encapsulation
is constituted by a Deleted Null Packet (DNP) field 7121 and a Header Deletion
Mode
(HDM) field 7122, and is present only when the AHF field 7113 is set to the
value "1".
[101] The ALP packet provides an overhead reduction mechanism for the MPEG-
2 TS
packet for improving transmission efficiency. In detail, a sync byte (0x47) of
each TS
packet is continuously deleted. As a result, the length of the MPEG-2 TS
packet en-
capsulated in the payload of the ALP packet continuously becomes not 188
bytes,
which is an original length, but 187 bytes.
[102] Further, the null TS packet deletion may be applied. In detail, in
order to avoid un-
necessary transmission overhead, the null TS packet (PID = Ox1FFF) may be
deleted,
and the deleted null TS packet may be restored by a receiver side by using the
DNP
field 7121.
[103] The DNP field 7121 corresponds to the fourth field as described
above, and indicates
the number of deleted null TS packets. Here, the deleted null TS packet may be
at least
one null TS packet which immediately precedes the first TS packet or which im-
mediately follows the last TS packet in each TS packet group included in the
payload
of the ALP packet among a plurality of packets included in the input stream.
[104] FIG. 8B is a diagram illustrating a header structure of an ALP packet
according to
another exemplary embodiment.
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[105] As an overhead reduction mechanism for the MPEG-2 TS packet for
improving
transmission efficiency, the TS header deletion may be selectively applied. At
least
two consecutive TS packets have continuity counter fields which are
sequentially
increased and when the header is the same across the TS packets, the header
may be
transmitted once in a first packet and the other headers may be deleted.
[106] When three overhead reduction mechanisms are performed, overhead
reduction may
be sequentially performed in the order of sync byte deletion, null packet
deletion, and
common header deletion. A syntax of MPEG-2 TS encapsulation is shown in Table
2.
[107] Table 2
[Table 2]
Syntax No. of bits Format
ATSC3.0_1ink_layer_packet()
packet_type 3 '111'
NUMTS 4 uimsbf
AHF 1 bslbf
if (AHF =="1")
HDM 1 bslbf
DNP 7 uimsbf
}
{108] An HDM field 7122 corresponds to the fifth field of a base header
7110 as described
above, and is a 1-bit field indicating whether the TS header deletion is
applied to the
ALP packet. The value "1" indicates that the TS header deletion is applied to
the ALP
packet, and the value "0" indicates that the TS header deletion is not
applied.
[109] Meanwhile, a maximum of 128 null packets may be deleted. When the
value of the
HDM field 7121 is "0", the value "0" of a DNP field 7122 indicates that 128
null TS
packets are deleted. When the value of the HDM field 7121 is "1", the value
"0" of the
DNP field 7122 indicates that the null TS packets are not deleted. The value
"0" of the
HDM field 7121 indicates that the TS header deletion is not applied, and the
null TS
packets are deleted.
[110] An additional header 7120 is present when an AHF field 7113 is set to
the value "1",
which also means that the null TS packet is deleted or the TS header
compression is
applied. As a result, when the value of the HDM field 7121 is "0", since the
value of
the DNP field 7122 need not indicate whether the null TS packets are deleted,
the
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value "O'' in the HDM field 7121 indicates that 128 null TS packets are
deleted. On the
contrary, when the value of the HDM field 7121 is "1", at least one null TS
packet may
be deleted or not. As a result, when the value of the HDM field 7121 is "1",
the value
"0" of the DNP field 7122 indicates that the null TS packets are not deleted.
[111] All values of the DNP field 7122 other than the value "0" are the
same as the number
of deleted null TS packets. For example, "5" which is a value of the DNP field
7122
indicates that 5 null packets are deleted.
[112] The AHF field 7113 corresponds to the third field of the base header
7110 as
described above, and is a 1-bit field indicating whether the additional header
is present.
A value "0" indicates that the additional header is not present, and a value
"1"
indicates that the additional header 7120 is present after the base header
7110. Here,
the additional header may be implemented by 1 byte. The AHF field 7113 may be
set
to the value "1" when the null TS packet is deleted or when the TS header
deletion is
applied.
[113] That is, the additional header 7120 for TS packet encapsulation
includes the HDM
field 7122 and the DNP field 7121, and is present only when the AHF field 7113
is set
to the value "1".
[114] The HDM field 7121 corresponds to the fifth field as described above,
and is a 1-bit
field indicating whether the TS header deletion is applied to the ALP packet.
The value
"1" indicates that the TS header deletion is applied to the ALP packet, and
the value
"0" indicates that the TS header deletion is not applied.
[115] The DNP field 7122 corresponds to the fourth field, and indicates the
number of
deleted null TS packets. Here, the deleted null TS packet may be at least one
null TS
packet which immediately precedes the first TS packet or immediately follows
the last
TS packet in each TS packet group included in the payload of the ALP packet
among a
plurality of packets included in the input stream.
[116] A maximum of 128 null packets may be deleted. When the value of the
HDM field
7121 is "0", the value of the DNP field 7122 of "0" indicates that 128 null TS
packets
are deleted. When the value of the HDM field 7121 is "1", the value of the DNP
field
7122 of "0" indicates that the null TS packets are not deleted. Sine the value
of the
HDM field 7121 of "0" indicates that the TS header deletion is not applied,
the value
"0" indicates that the null TS packets are particularly deleted.
[117] FIG. 9 is a diagram for describing a null packet deletion mechanism
according to an
exemplary embodiment.
[118] According to a transmission stream rule, a bit rate is required to be
the same at an
output of a multiplexer of a transmitting apparatus and an input of a
demultiplexer of a
receiving apparatus, and an end-to-end delay is also required to be the same
at the
transmitting apparatus and the receiving apparatus. In the case of some
transmission
CA 3022469 2018-10-29
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stream input signals, a null packet may be present in order to receive a
variable bit rate
service in a predetermined bit rate stream. In this case, in order to prevent
unnecessary
transmission overhead, a null TS packet (PID = 0x1F1-1-) may be deleted. A
process in
which the deleted null TS packet is reinserted into the original location in
the receiving
apparatus is performed, and as a result, a predetermined bit rate may be
guaranteed and
the need of Program Clock Reference (PCR) time stamp update may be prevented.
[119] Before generating an ALP packet, a counter called DNP is reset to
zero and increases
with respect to respective deleted null TS packets prior to encapsulation into
the ALP
packet.
[120] A group of consecutive valid TS packets is encapsulated into a
payload of the ALP
packet, and each field value of a header is determined. After the generated
ALP packet
is injected into a physical layer, the DNP is reset to zero. In the case where
the DNP
reaches a maximum value, when a next packet is also a null packet, this null
packet is
regarded as a valid packet and encapsulated into the payload of the next ALP
packet.
Each ALP packet includes at least one valid TS packet in the payload.
[121] FIG. 9 illustrates HD1\4=`0' and AHF=` l' with respect to two ALP
packets. In a first
ALP packet 910, one null packet is deleted before two valid TS packets are
transmitted
to the ALP packet 910. When the next packet is a null packet, the ALP packet
910 is
completed and the DNP counter is reset to zero. In a header of the ALP packet
910,
NUMT='2' and DNP,` I'. In a second ALP packet 920, two null packets are
deleted
before four valid TS packets are transmitted to the ALP packet 920. In this
case, in a
header of the corresponding ALP packet 920, NUMT='4' and DN13=`2'.
[122] FIGs. 10A and 10B are diagrams for describing a null packet deletion
mechanism
according to another exemplary embodiment.
[123] As illustrated in FIGs. 10A and 10B, a DNP field 1010 may include the
number of
deleted null packets with respect to each of a plurality of TS packet groups
constituted
by consecutive TS packets. Here, deleted null packets with respect to
respective TS
packet groups 1021, 1022 and 1023 may be null packet groups 1031, 1032 and
1033
including a plurality of null TS packets subsequently preceding a first TS
packet
included in each of the TS packet groups among a plurality of packets included
in an
input stream.
[124] A DNP pointer field 1011 is a field indicating whether a null packet
deleted with
respect to each TS packet group is present. An i-th bit of the DNP pointer
field
indicates whether a null TS packet deleted before an i-th TS packet in a
payload of an
ALP packet is present. For example, when the number of valid TS packets
transmitted
in an ALP packet is 8 or less, the DNP pointer field 1050 may become 1 byte.
Further,
when the number of valid TS packets transmitted in an ALP packet is greater
than 8
but equal to or less than 16, the DNP pointer field 1011 may become 2 bytes.
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[125] DNP fields 1012, 1013 and 1014 indicate the numbers of null TS
packets deleted
with respect to deleted consecutive null TS packet groups, respectively. For
example,
each of the DNP fields 1012, 1013 and 1014 may be implemented as 8 bits.
L126] As illustrated in FIG. 10B, the numbers 1041, 1042 and 1043 of null
packets 1031,
1032 and 1033 deleted with respect to three TS packet groups 1021, 1022 and
1023
each being constituted by consecutive valid TS packets, respectively, are
counted, and
the numbers of null packets which are counted may be included in the DNP
fields
1012, 013 and 1014 of an ALP packet header 1100, respectively. Here, the null
packets
1031, 1032 and 1033 deleted with respect to the respective TS packet groups
1021,
1022 and 1023 may be null packet groups 1031, 1032 and 1033 including null TS
packets subsequently preceding a first TS packet included in each of the TS
packet
groups among a plurality of packets included in an input stream.
[127] FIG. 11 is a diagram for describing a TS header deletion mechanism
according to
another exemplary embodiment.
[128] At least two consecutive TS packets sequentially increase consecutive
counter fields,
and when the header fields of these TS packets are the same, that is,
redundant, the
header is transmitted once in the first TS packet and the other headers are
deleted.
When a duplicated MPEG-2 TS packet is included in at least two consecutive TS
packets, header deletion is applied at a transmitter side. An I-1DM field
indicates
whether the header deletion is performed. When a TS packet header is deleted,
the
HDM field is set to "1".
[129] FIG. 11 illustrates an exemplary embodiment when three TS packets
have the same
header field and NUMT='4'. While AHF,-`1', HDM-=`1' and NDP.`0'. That is, in
this
case, TS header deletion is applied and null packet deletion is not applied.
In a receiver
side, the deleted packet header is recovered by using a first packet (1010)
header and a
consecutive counter is sequentially increased and restored from the first
header.
[130] FIG. 12 is a block diagram illustrating a configuration of a
transmitting apparatus
according to another exemplary embodiment. Referring to FIG. 12, the
transmitting
apparatus 100' includes a packet generator 110, a frame generator 130, a
signal
processor 140, and a transmitter 150. Among the components illustrated in FIG.
12,
since the constitution of the packet generator 110 is the same as the
constitution of the
packet generator 110 illustrated in FIG. 6, a detailed description will be
omitted.
[131] The packet generator 110 generates a packet, for example, an ALP
packet (generic
packet) as described above.
[132] The frame generator 130 may generate a frame including the ALP packet
generated
by the packet generator 110. Herein, the generated frame may be a baseband
packet
(BBP) (alternatively referred to as a layer 1 (L1) packet) including the ALP
packet.
Here, the terms to describe the transmitting apparatus of FIG. 12 may vary
according
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to a system design. For example, the ALP packet and the BBP packet may be
referred
to as a BBP packet and a baseband frame (BBF), respectively, in another
system.
[133] In detail, the frame generator 130 arranges a plurality of ALP
packets including a TS
packet or an IP packet and a header to generate the arranged ALP packets as a
baseband packet having a size corresponding to an FEC code. The ALP packets
according to the exemplary embodiment may be TS packets, but the same process
may
be applied to various types of data as well as the TS packets.
[134] FIG. 13 is a block diagram illustrating a detailed configuration of a
frame generator
according to an exemplary embodiment.
[135] Referring to FIG. 13, the frame generator 130 may include a baseband
header
generator 130-1 and a baseband packet generator (also referred to as a
baseband packet
constructor) 130-2. In addition, the baseband packet generator 130-2 may
transmit a
generated baseband packet to a baseband packet scrambler 135.
[136] The baseband header generator 130-1 may generate a header inserted
into the
baseband packet. Here, the header inserted into the baseband packet is
referred to as a
baseband header and the baseband header includes information on the baseband
packet.
[137] In particular, the baseband header generator 130-1 may generate the
baseband header
including information on the number of TS packets in an ALP packet, the number
of
deleted null packets, and the like when an input stream is a TS. Besides, the
baseband
header generated by the baseband header generator 130-1 may include various in-
formation and this will be described below.
[138] Further, the baseband packet generator 130-2 encapsulates the
baseband header
generated from the baseband header generator 130-1 and ALP packets output from
the
packet generator 110 to generate a baseband packet.
11391 In addition, the baseband packet scrambler 135 mixes data stored in
the baseband
packet in a random order before an FEC code is applied to the baseband packets
to
generate a scrambled baseband packet. The scrambled baseband packet is
transmitted
through at least one PLP and signal-processed. In this case, one PLP may be
con-
stituted by baseband packets having a fixed size. That is, the input stream
may be en-
capsulated to a baseband packet for one PLP.
[140] The PLP means a signal path which is independently processed. That
is, respective
services (for example, video, extension video, audio, a data stream, and the
like) may
be transmitted and received through multiple RF channels and the PLP is a path
through which the services are transmitted or a stream transmitted through the
path.
Further, the PLP may be positioned at slots distributed on multiple RF
channels with a
time interval or distributed on one RF channel with a time interval. That is,
one PLP
may be transmitted while being distributed on one RF channel or multiple RF
channels
CA 3022469 2018-10-29
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with a time interval.
[141] A PLP structure is constituted by Input mode A providing one PLP and
Input mode
B providing multiple PLPs, and, in particular, when the PLP structure supports
Input
mode B, the PLP structure may provide a strong specific service and a time in-
terleaving length is increased by distributing and transmitting one stream to
acquire a
time diversity gain. Further, when only a specific stream is received, a power
supply of
a receiver may be turned off for a residual time to be used with low power,
and as a
result, the receiver is suitable for providing a portable and mobile
broadcasting service.
[142] The time diversity is a technology that when a transmitting side
transmits the same
signal with a predetermined time interval several times in order to reduce
deterioration
of a transmission quality in a mobile communication transmission path, a
receiving
side synthesizes the received signals again to acquire an excellent
transmission quality.
[143] Further, information which may be commonly transmitted to a plurality
of PLPs is
transmitted through one PLP to increase transmission efficiency and PLPO
performs
such a role. When the PLP is referred to as a common PLP and PLPs other than
PLPO
may be used for data transmission and these PLPs are referred to as a data
PLP. When
such PLPs are used, a home high-definition TV (HDTV) program may be received
and, in a mobile situation, a standard definition TV (SDTV) program may be
provided
to mobile devices. Further, various broadcasting services may be provided to a
viewer
through a broadcasting station or a broadcasting content provider, and
differentiated
broadcasting services may be provided to receivers located even in a fringe
area where
service reception is very difficult.
[144] Meanwhile, FIG. 14 is a diagram illustrating an ALP packet, a
baseband packet, and
a scrambled baseband packet according to an exemplary embodiment.
[145] Referring to FIG. 14, when the packet generator 110 stores at least
one TS or IP
packet in a payload and inserts a header to generate a plurality of ALP
packets 111 and
112, the frame generator 130 groups the plurality of generated ALP packets 111
and
112, and inserts a baseband header to generate a plurality of baseband packets
121 and
122. Here, the respective baseband packets 121 and 122 may include a plurality
of
ALP packets and further, may include some of an ALP packet.
[146] The baseband packet scrambler 135 randomly scrambles the respective
generated
baseband packets 121 and 122 to generate a plurality of scrambled baseband
packets,
for example, a scrambled baseband packet 125-1. In addition, the generated
scrambled
baseband packet 125-1 may be transmitted to at least one PLP as described
above and
subjected to signal processing for adding an FEC code.
11471 Referring back to FIG. 12, the signal processor 140 may signal-
process the generated
baseband packet which may be a scrambled baseband packet.
[148] In detail, the signal processor 140 signal-processes the baseband
packet to generate a
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transmission frame.
[149] Further, the signal processor 140 may insert signaling information
into a signaling
area of a frame. Herein, the signaling information may be called an Li
signaling signal
for frame synchronization. A preamble into which the Ll signaling information
is
inserted may include an Li pre signaling area and an Li post signaling area.
[150] Meanwhile, although not illustrated, the signal processor 140 may
perform functions
corresponding to bit the BICM blocks 12000 and 12000-1 and the
framing/interleaving
blocks 13000 and 13000-1 illustrated in FIG. 3A to 3C.
[151] The transmitter 150 may transmit the signal-processed frame to a
receiving apparatus
(not illustrated).
[152] In detail, the transmitter 150 may perform functions corresponding to
the waveform
generation blocks 14000 and 14000-1 illustrated in FIGs. 3A to 3C. That is,
the
transmitter 140 performs modulation for modulating the generated frame to an
RF
signal and transmits the RF signal to the receiving apparatus.
[153] Hereinafter, a TS packet encapsulation mechanism according to various
exemplary
embodiments will be described in detail with reference to the accompanying
drawings.
However, detailed description about parts which are redundant with those about
the
aforementioned parts will be omitted.
[154] FIG. 15 is a diagram for describing a TS packet encapsulation
mechanism according
to an exemplary embodiment.
[155] As described above, an ALP packet may transmit an MPEG-2 TS packet
without a
sync byte in a payload. FIG. 15 illustrates an ALP packet including eight MPEG-
2 TS
packets. An encapsulation process is described below:
[156] - The sync byte for the MPEG-2 TS packet is deleted for
encapsulation. As a result,
the length of the MPEG-2 TS packet decreases from 188 bytes to 187 bytes.
11571 - Eight MPEG-2 TS packets are grouped to a payload of an ALP packet.
In this case,
the length of the payload becomes 187 x 8 = 1,496 bytes.
[158] - An ALP header, i.e., a base header of an ALP packet header, having
a length of 1
byte is generated. Here, the ALP header has a value of packet_type (1410) =
'111',
NUMTS (1420) = '1000', AHF (1430) = '0'.
[159] In the ALP packet generated as described above, 7 bytes are saved as
compared with
a case in which eight MPEG-2 TS packets are directly transmitted to a PHY
layer.
[160] FIG. 16A is a diagram for describing a TS packet encapsulation
mechanism
according to another exemplary embodiment.
[161] As described above, an ALP packet may be generated by deleting at
least one null
MPEG-2 TS packet disposed immediately before the first MPEG-2 TS packet en-
capsulated into the ALP packet, and a receiver may know the number of null
MPEG-2
TS packets deleted through a header of the ALP packet. FIG. 16A illustrates an
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example of an ALP packet including six MPEG-2 TS packets when two null MPEG-2
IS packets are deleted disposed immediately before the first MPEG-2 TS packet
in a
payload. The encapsulation process is described below.
[162] - At least one null packet is deleted and counted.
[163] - At least one sync byte of at least one MPEG-2 TS packet is deleted
for encap-
sulation. As a result, the length of an M PEG-2 TS packet decreases from 188
bytes to
187 bytes.
[164] - Six MPEG-2 TS packets arc grouped to a payload of an ALP packet. In
this case,
the length of the payload becomes 187 x 6 = 1,122 bytes.
[165] - An ALP header, i.e., a base header of an ALP packet header, having
a length of 2
bytes is generated. Here, the ALP header has a value of packet_type (1510) =
'111',
NUMTS (1520) = '0110', AHF (1530) = '1', HDM (1540) = '0', DNP (1550) =
'0000010'. In this case, AHF = l' indicates that at least two consecutive null
packets
are deleted disposed immediately before the first TS packet encapsulated into
a
payload.
[166] The length of the ALP packet generated as described above is 1,124
bytes and 380
bytes are saved as compared with a case in which six MPEG-2 TS packets are
directly
transmitted to a PHY layer.
[167] FIG. 16B is a diagram for describing a decapsulation mechanism of an
ALP packet
illustrated in FIG. 16A.
[168] The decapsulation process at a receiver side is described below.
[169] - A DNP field 1550 is checked.
[170] - The number of TS packets is checked in the ALP packet by using the
NUMTS field
1520.
[171] - The sync bytes are inserted.
11721 - The null packets which were disposed immediately before the valid
TS packet
group, that is the first TS packet, indicated in the DNP field 1550 are
generated.
[173] FIG. 17A is a diagram for describing TS packet encapsulation and a TS
header
deletion mechanism according to yet another exemplary embodiment.
[174] As described above, an ALP packet may be generated by compressing a
header of an
MPEG-2 IS packet additionally encapsulated into the ALP packet. FIG. 17A il-
lustrates an example of an ALP packet including eight MPEG-2 TS packets having
the
same header except a continuity counter (CC) field. The encapsulation process
is
described below.
[175] - Eight TS packets having the same field except for the CC field are
grouped.
[176] - The header (except for the sync bytes) is maintained only with
respect to the first
MPEG-2 TS packet and the header is deleted with respect to the other seven
MPEG-2
TS packets. In this case, the length of the payload becomes 3 + 184 x 8 =
1,475 bytes.
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Here, the TS header may be 3 bytes.
[177] - An ALP header, i.e., a base header of an ALP packet header, having
a length of 2
bytes is generated. Here, the ALP header has a value of packet_type (1710) =
'111',
NUMTS (1720) = '0100', AHF (1730) = '1', HDM (1740) = '1', DNP (1750) =
'0000010'.
[178] The length of the ALP packet generated as described above is 1,477
bytes and 27
bytes are saved as compared with a case in which eight MPEG-2 TS packets are
directly transmitted to the PHY layer.
[179] FIG. 17B is a diagram for describing decapsulation and TS header
restoration
mechanisms of the ALP packet illustrated in FIG. 17A, according to an
exemplary em-
bodiment.
11801 The decapsulation process at a receiver side is described below.
[181] The decapsulation process at the receiver side is described below.
[182] - The TS header deletion is detected by reading the HDM field 1740.
[183] - The number of TS packets is checked in the ALP packet by using the
NUMTS field
1720.
[184] - The first TS packet includes a 3-byte header and a 184-byte payload
and the other
TS packets include only the 184-byte payload.
[185] - All TS packets are generated by using the header of the first TS
packet. In this case,
the consecutive CC field increases one by one.
[186] - The sync bytes are inserted.
[187] FIGs. 18A to 18C arc diagrams for describing a header structure of an
ALP packet
according to another exemplary embodiment.
[188] FIG. 18A is a diagram illustrating a structure of a base header
included in a header of
an ALP packet according to another exemplary embodiment.
11891 A Packet_Type field 1810 is the same as the Packet_Type field 7111
illustrated in
FIG. 8A.
[190] An NPDI field 1820 indicates whether at least one null TS packet is
deleted. For
example, the NPDI field 1820 is implemented as 1 bit, and a value "1"
indicates that
the null TS packet is deleted and a value "0" indicates that the null TS
packet is not
deleted. Here, the header does not include an additional header illustrated in
FIGs. 18B
and 18C.
[191] A NUMTS field 1830 is the same as the NUMTS field 7112 illustrated in
FIG. 8A.
[192] FIGs. 18B and 18C illustrate a structure of an additional header
included in a header
of an ALP packet according to another exemplary embodiment. The additional
header
is present only when the value of the NPDI field 1820 illustrated in FIG. 18A
is "1",
and the additional header may be called an optional header according to a
system
design.
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[193] An EXT field 1840 indicates the number of deleted null TS packet
groups. For
example, the EXT field 1840 is implemented as a 1-bit field, and when the
number of
groups of deleted consecutive null TS packets is at most one, the EXT field
1840 is set
to "0". On the contrary, when the EXT field 1850 is set to "1", the number of
groups of
consecutively deleted null TS packets is two or more and an extended header is
present.
[194] A DNP field 1850 indicates the number of null TS packets. For
example, the DNP
field 1850 may be implemented as a 7-bit field. According to an exemplary em-
bodiment, when the EXT field 1840 is "0", the EXT field 1840 indicates the
number of
deleted null TS packets precedent to a TS packet group, and when the EXT field
1840
is "1", the EXT field 1840 indicates the number of null TS packets deleted
with respect
to a first group of deleted consecutive null TS packets. According to another
exemplary embodiment, when the EXT field 1840 is "0", the EXT field 1840
indicates
the number of deleted null TS packets after the TS packet group, and when the
EXT
field 1840 is "1", the EXT field 1840 indicates the number of null TS packets
deleted
with respect to the first group of the deleted consecutive null TS packets.
The EXT
field 1840 may be disposed prior to the DNP field 1850 and vice versa as
illustrated in
FIGs. 18B and 18C.
[195] FIG. 19 is a diagram for describing a TS packet encapsulation process
using the
header structure illustrated in FIGs. 18A to 18C, according to an exemplary em-
bodiment.
[196] As illustrated in FIG. 19, the ALP packet may be created in an
illustrated form
through the TS packet encapsulation process.
[197] In detail, a Type field 1911 is a value (for example, '010')
indicating that the packet
included in a payload of an ALP packet is a TS packet, an NPDI field 1912 is a
value
(for example, '1') indicating that at least one null packet is deleted, a
NUMTS field
1913 is a value (for example, '1010') indicating that the number of TS Packets
is 10,
an EXT field 1914 is a value (for example, '1') indicating that the number of
groups of
deleted consecutive nulls TS packets is two or more, and an i-th bit of a DNP
pointer
field 1915 indicates whether a null TS packet deleted after an i-th TS packet
is present
in the payload. This DNP pointer field structure is different from that of the
DNP
pointer 1011 in FIG. 10B, which indicates whether a null TS packet deleted
before an
i-th TS packet is present in the payload. This is because a null TS packet
immediately
after the last TS packet in the payload is deleted prior to encapsulation, in
which case
the DNP pointer field structure in FIG. 10B cannot indicate the presence of
the deleted
null TS packet after the last TS packet in the payload. Specifically, if the
DNP pointer
field 1915 is set to a value '0000 1010 0000 0000' according to the DNP
pointer field
structure in FIG. 10B, the DNP pointer field 1915 is able to indicate only the
presence
CA 3022469 2018-10-29
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of deleted null TS packets before the fifth TS packet and the seventh TS
packet, but is
not able to indicate the presence of the last TS packet in the payload.
Respective DNP
fields 1916, 1917 and 1918 may be set to values (for example, '0000010', '0000
0011', and '0000 0001') indicating that the numbers of null TS packets deleted
with
respect to deleted consecutive null TS packet groups are 2, 3 and 1,
respectively.
[198] Meanwhile, when the ALP packet is extracted at a receiver side, it is
determined that
the ALP packet includes the MPEG-2 TS packet based on '010' which is the value
of
the Type field 1911 of the ALP header. The null TS packet is deleted based on
'1'
which is the value of the NPDI field 1912, and it is determined that the
additional
header is present. Further, it is determined that the ALP packet includes 10
valid TS
packets based on '1010' which is the value of the NUMTS field 1913.
[199] Further, two or more null TS packet groups are deleted in the current
ALP packet
based on '1' which is the value of the EXT field 1914 and it is determined
that an
extended header is present.
[200] It is determined that a first null TS packet group includes two null
TS packets based
on '0000010' which is the value of the DNP 1 field 1916 and it is determined
that null
TS packet groups are present after a fourth TS packet, a sixth TS packet, and
a tenth
TS packet, respectively based on the value of the DNP pointer field 1915.
Further, it is
determined that second and third null TS packet groups include three null TS
packets
and one null TS packet by using '0000 0011' which is the value of the DNP 2
field
1917 and '0000 0001' which is the value of the DNP 3 field 1918, respectively.
[201] Based on the determination result, four TS packets of the payload is
output, and
thereafter, two null TS packets are output, two TS packets among the residual
TS
packets of the payload are output, and thereafter, three nulls TS packets are
output, and
four residual TS packets of the payload are output, and thereafter, one null
TS packet is
output to decapsulate the ALP packet.
[202] FIGs. 20A and 20B are diagrams for describing an ALP packet header
structure
according to another exemplary embodiment.
[203] The configuration illustrated in FIGs. 20A and 20B illustrate an
additional header
structure according to another exemplary embodiment, and a configuration of a
base
header may be the same as that of the base header.
[204] An EXT field 2010 indicates the number of deleted null TS packet
groups. For
example, the EXT field 2010 is implemented as a 1-bit field, and when the
number of
groups of deleted consecutive null TS packets is at most one, the
corresponding field is
set to "0". On the contrary, when the EXT field 2010 is set to "1", the number
of
groups of deleted consecutive null TS packets is two or more and an extended
header
is present.
[205] A DNP field 2020 indicates the number of null IS packets deleted
before a TS
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packet group. For example, the DNP field 2020 may be implemented as a 7-bit
field.
According to an exemplary embodiment, the DNP field 2020 may be present only
when the EXT field 2010 is "0". According to another exemplary embodiment, the
DNP field 1850 indicates the number of null TS packets deleted after the TS
packet
group.
[206] A DNPG field 2025 indicates the number of deleted null TS packet
groups. For
example, the DNP field 2025 may be implemented as the 7-bit field. The DNPG
field
2025 may be present only when the EXT field 2010 is "1".
[207] Meanwhile, in a last TS packet of each TS packet group in which a
null TS packet
group is deleted after the TS packet group, a transport error indicator (TEI)
field value
may be set to 1.
12081 FIG. 21 is a diagram for describing a TS packet encapsulation process
using the
header structure illustrated in FIGs. 20A and 20B, according to an exemplary
em-
bodiment.
[209] As illustrated in FIG. 21, the ALP packet may be created in an
illustrated form
through the TS packet encapsulation process.
[210] In detail, a Type field 2111 is a value (for example, '010')
indicating that the packet
included in a payload of an ALP packet is a TS packet, an NPDI field 2112 is a
value
(for example, '1') indicating that at least one null packet is deleted, a
NUMTS field
2113 is a value (for example, '1010') indicating that the number of TS Packets
is 10,
an EXT field 2114 is a value (for example, '1') indicating that the number of
groups of
deleted consecutive nulls TS packets is two or more, and an i-th bit of a DNPG
field
2115 is a value (for example, '000011') indicating that three null TS packet
groups are
deleted in the ALP packet, and respective DNP fields 2116, 2117 and 2118 may
be set
to values (for example, '0000010', '0000 0011', and '0000 0001') indicating
that the
numbers of null TS packets deleted with respect to respective deleted
consecutive null
TS packet groups are 2, 3 and 1, respectively.
[211] Meanwhile, when the ALP packet is extracted at a receiver side, it is
determined that
the current ALP packet includes the MPEG-2 TS packet based on '010' which is
the
value of the Type field 2111 of the ALP header. The null TS packet is deleted
based on
'1' which is the value of the NPDI field 2112, and it is determined that an
additional
header is present. Further, it is determined that the current ALP packet
includes 10
valid TS packets based on '1010' which is the value of the NUMTS field 2113.
[212] Further, two or more null TS packet groups are deleted in the current
ALP packet
based on '1' which is the value of the EXT field 2114 and it is determined
that an
extended header is present and subsequent 7 bits are the DNPG field.
[213] It is determined that three groups of deleted null TS packets are
present based on
'0000011' which is the value of the DNPG field 2115.
CA 3022469 2018-10-29
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[214] It is determined that a first null TS packet group includes two null
TS packets based
on '0000010' which is the value of the DNP 1 field 2116, and it is determined
that
second and third null TS packet groups include three and one null TS packets,
re-
spectively by using '0000 0011' which is the value of the DNP 2 field 1917 and
'0000
0001' which is the value of the DNP 3 field 1918.
[215] Further, by examining a TEl field while outputting each TS packet,
two null TS
packets are output after a first packet in which the TEl field value of the TS
packet is
1, three null TS packets are output after a second packet in which the TEl
field value of
the TS packet is 1, and one null TS packet is output after the first packet in
which the
TEl field value of the TS packet is 1 to decapsulate the ALP packet.
[216] FIG. 22 is a diagram for describing a TS packet encapsulation
mechanism according
to yet another exemplary embodiment.
[217] As illustrated in FIG. 22, a separate DNP field is not used in a
header, and DNP
values 2241, 2242 and 2243 may be recorded in locations where respective null
TS
packet groups 2231, 2232 and 2233 are deleted in a payload. In this case, a
base header
may similarly include a TYPE field 2211, an NPDI field 2212 and an NUMTS field
2213, and an additional header may include only an EXT field 2114 and a DNPG
field
2115. However, in some cases, the DNPG field 2115 may be omitted.
[218] Meanwhile, when the exemplary embodiments are used in one system, the
EXT field
is extended to an appropriate bit number (for example, 2 bits) to indicate
what method
is used.
[219] FIG. 23 is a flowchart for describing a signal processing method of a
transmitting
apparatus, according to an exemplary embodiment.
[220] According to the signal processing method of the transmitting
apparatus illustrated in
FIG. 23, first, a packet including a header and a payload corresponding to an
input
stream, that is, an ALP packet is generated (S2310). A base header
constituting the
header may include a first field representing a packet type of an input stream
and when
the first field is set to a value indicating that the packet type of the input
stream is a TS
packet, the base header may include a second field indicating the number of TS
packets included in the payload and a third field set to a first value
indicating that there
is no additional header or a second value indicating that there is the
additional header,
and when the third field is set to the second value, the additional header
includes a
fourth field indicating the number of deleted null packets with respect to
each of at
least one TS packet group constituted by consecutive TS packets. The null
packet
deleted with respect to each TS packet group becomes null TS packet
subsequently
preceding the first TS packet included in each TS packet group among the
plurality of
packets included in the input stream.
[221] Subsequently, a frame including the generated packet, that is, a
baseband packet is
CA 3022469 2018-10-29
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generated (S2320).
[222] The generated baseband packet is signal-processed (S2330).
[223] Thereafter, the signal-processed frame is transmitted (S2340).
Herein, the signal-
processed frame may become a transmission frame.
[224] FIG. 24A is a block diagram illustrating a configuration of a
receiving apparatus
according to an exemplary embodiment.
[225] Referring to FIG. 24A, the receiving apparatus 200 includes a
receiver 210 and a
signal processor 220.
[226] The receiving apparatus 200 may be implemented to receive data from a
transmitting
apparatus that maps data included in the input stream to at least one signal
processing
path and transmits the mapped data.
12271 The receiver 210 receives a frame including the data mapped to at
least one signal
processing path. In detail, the receiver 210 may receive a stream including
signaling
information and the data mapped to at least one signal processing path.
Herein, the
signaling information may include information on an input type of the input
stream
input into the transmitting apparatus and information on a data type mapped to
at least
one signal processing path. Herein, the information on the input type of the
input
stream may indicate whether all signal processing paths in the frame are the
same input
type. Besides, since detailed information included in the signaling
information has
been described above, detailed description will be omitted.
[228] The signal processor 220 extracts the signaling information from the
received frame.
In particular, the signal processor 220 may acquire various information on the
corre-
sponding PLP included in an Li pre signaling area and an Li post signaling
area by
extracting and decoding Ll signaling. Further, the signal processor 230 may
signal-
process the frame based on the extracted signaling information. For example,
in the
signal processing, demodulation, frame de-builder, BICM decoding, and input de-
processing processes may be performed.
[229] In detail, the signal processor 220 signal-processes the transmission
frame received
by the receiver 210 to generate the bascband packet and extracts the header in-
formation from the ALP packet included in the generated baseband packet.
[230] In addition, the signal processor 220 signal-processes payload data
included in the
ALP packet based on the extracted header information to restore the stream,
that is, the
input stream first input into the transmitting apparatus 100. Herein, the
extracted
header information includes a field indicating a payload data type and a field
indicating
whether the ALP packet transmits a complete input packet.
[231] FIG. 24B is a block diagram illustrating a signal processor according
to an exemplary
embodiment in detail.
[232] Referring to FIG. 24B, the signal processor includes a demodulator
221, a decoder
CA 3022469 2018-10-29
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222, and a stream generator 223.
[2331 The demodulator 221 performs demodulation according to an OFDM
parameter from
a received RF signal to perform sync detection, and, when the sync is
detected,
recognizes whether a frame currently received is a frame including required
service
data from signaling information stored in a sync area. For example, whether a
mobile
frame is received or whether a fixed frame is received may be recognized.
[234] In this case, when OFDM parameters for a signaling area and a data
area are not pre-
determined, the OFDM parameters for the signaling area and the data area
stored in the
sync area are acquired to demodulate OFDM parameter information for a
signaling
area and a data area immediately subsequent to the sync area.
[235] The decoder 222 decodes the required data. In this case, the decoder
222 may acquire
and decode parameters including an FEC scheme, a modulation scheme, and the
like
for data stored in each data area by using the signaling information. Further,
the
decoder 223 may calculate the location of the required data based on the data
in-
formation included in the header. That is, at which location of the frame a
required
PLP is transmitted may be calculated.
[236] The stream generator 223 processes the baseband packet received from
the decoder
222 to generate data to be serviced.
[237] As one example, the stream generator 223 may generate an ALP packet
from an
error-corrected baseband packet based on various information. In detail, the
stream
generator 223 may include de-jitter buffers and the de-jitter buffers may
regenerate an
accurate timing for restoring an output stream based on various information.
As a
result, a delay for sync among a plurality of PLPs may be compensated.
[238] FIG. 25 is a block diagram illustrating a configuration of a receiver
according to an
exemplary embodiment.
12391 Referring to FIG. 25, the receiver 2100 may include a controller
2110, an RF
receiver 2120, a demodulator 2130, and a service reproducer 2140.
[240] The controller 2110 determines an RF channel and a PLP in which a
selected service
is transmitted. In this case, the RF channel may be specified as a center
frequency and
a bandwidth, and the PLP may be specified as a PLP identifier (ID). A specific
service
may be transmitted through one or more PLPs that belong to one or more RF
channels
for each of components constituting the service, but hereinafter, it is
assumed that all
data required to reproduce one service are transmitted to one PLP transmitted
to one
RF channel for easy description. That is, the service has a unique data
acquisition path
for reproducing the service, and the data acquisition path is specified as the
RF channel
and the PLP.
[241] The RF receiver 2120 detects an RF signal in the RF channel selected
by the
controller 2110, and transfers to the demodulator 2130 OFDM symbols extracted
by
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signal-processing the RF signal. Here, the signal processing may include
synchro-
nization, channel estimation, and equalization, and information for the signal
processing is a value predetermined by the transmitter and the receiver or is
included in
a specific OFDM symbol predetermined among OFDM symbols to be transferred in
the receiver according to a system design.
[242] The demodulator 2130 signal-processes the OFDM symbols to extract a
user packet
and transfers the extracted user packet to the service reproducer 2140, and
the service
reproducer 2140 reproduces and outputs a service selected by the user by using
the
user packet. In this case, a format of the user packet may vary depending on
an imple-
mentation scheme of the service and as one example, a TS packet or an IPv4
packet is
provided.
12431 FIG. 26 is a block diagram illustrating the demodulator illustrated
in FIG. 25
according to an exemplary embodiment in more detail.
[244] Referring to FIG. 26, the demodulator 2130 may be configured to
include a frame
&mapper 2131, a BICM decoder 2132 for the Li signaling, a controller 2133, a
BICM
decoder 2134, and an output processor 2135.
[245] The frame demapper 2131 selects OFDM cells constituting FEC blocks
that belong
to a PLP selected in a frame constituted by the OFDM symbols based on control
in-
formation transferred in the controller 2133, and transfers the selected OFDM
cells to
the BICM decoder 2134 and further, selects the OFDM cells corresponding to one
or
more FEC blocks included in the Li signaling, and transfers the selected OFDM
cells
to the BICM decoder 2132 for the Li signaling.
[246] The BICM decoder 2132 for the Li signaling signal-processes the OFDM
cell corre-
sponding to the FEC block included in the Li signaling to extract Li signaling
bits,
and transfers the extracted Li signaling bits to the controller 2133. In this
case, the
signal processing may include a process of extracting a log-likelihood ratio
(LLR)
value for decoding an Low Density Parity Check (LDPC) code in the OFDM cell
and a
process of decoding the LDPC code by using the extracted LLR value.
[247] The controller 2133 extracts an Li signaling table from the Li
signaling bits and
controls operations of the frame demapper 2131, the BICM decoder 2134, and the
output processor 2135 by using a value of the Li signaling table. In FIG. 22,
it is il-
lustrated that the BICM decoder 2132 for the Ll signaling does not use the
control in-
formation of the controller 2133 for easy description. However, when the L2
signaling
has a hierarchical structure similar to structures of the Li-pre and the Li-
post, the
BICM decoder 2132 for the Li signaling may be constituted by one or more BICM
decoding blocks and it is apparent that operations of the BICM decoding blocks
and
the frame demapper 2131 may be controlled by higher-layer Li signaling
information.
[248] The BICM decoder 2134 signal-processes the OFDM cells constituting
the FEC
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blocks that belong to the selected PLP to extract a baseband packet, and
transfer the
baseband packet to the output processor 2135. The signal processing may
include a
process of extracting an LLR value for encoding and decoding the LDPC code in
the
OFDM cell and a process of decoding the LDPC code by using the extracted LLR
value, and be performed based on the control information transferred in the
controller
2133.
[249] The output processor 2135 signal-processes the baseband packet to
extract a user
packet and transfers the extracted user packet to the service reproducer 2140.
In this
case, the signal processing may be performed based on the control information
transferred in the controller 2133.
[250] FIG. 27 is a flowchart schematically illustrating an operation of a
receiver from the
time when a user selects a service up to the time when the selected service is
actually
reproduced according to an exemplary embodiment.
[251] It is assumed that before service selection of a user (S2710),
service information of
all services which are selectable is acquired in initial scan (S2700). Here,
the service
information may include information on an RF channel and a PLP in which data
required to reproduce a specific service is transmitted in a current
broadcasting system.
One example of the service information includes Program-Specific Information/
Service Information (PSI/SI) of MPEG2-TS and may be generally acquired through
L2
signaling and higher-layer signaling.
[252] When the user selects a service (S2710), the receiver changes a
current frequency to
a frequency to transmit the selected service (S2720) and performs RF signal
detection
(S2730). During the process of changing the current frequency to the frequency
to
transmit the selected service (S2720), the service information may be used.
[253] When the RF signal is detected, the receiver performs an Li signaling
extraction
operation (S2740) from the detected RF signal. Thereafter, the receiver
selects the PLP
that transmits the service selected by using the Li signaling extracted in the
previous
process (S2750) and extracts a baseband packet from the selected PLP (S2760).
During
the process of selecting the PLP that transmits the selected service (S2750),
the service
information may be used.
[254] Further, a process of extracting the baseband packet (S2760) may
include a process
of selecting OFDM cells that belong to the PLP by demapping a transmission
frame,
extracting an LLR value for encoding/decoding an LDPC code in an OFDM cell,
and a
process of decoding the LDPC code by using the extracted LLR value.
[255] The receiver performs ALP packet extraction (S2770) from the baseband
packet
extracted by using header information of the extracted baseband packet, and
performs
user packet extraction (S2780) from the ALP packet extracted by using header
in-
formation of the ALP packet extracted afterwards. The extracted user packets
are used
CA 3022469 2018-10-29
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for selected service reproduction (S2790). In the ALP packet extraction
(S2770)
process and the user packet extraction (S2780) process, Li signaling
information
acquired in the Li signaling extraction (S2740) step may be used. In this
case, the
process of extracting the user packet from the ALP packet (restoring the Null
TS
packets and inserting the TS sync bytes) is similar to the aforementioned
process.
[256] According to the various exemplary embodiments as described above,
various types
of data may be mapped to the transmittable physical layer at a transmitter
side and data
processing efficiency may be improved. Further, a packet is filtered in a link
layer at a
receiver side to increase data processing efficiency.
[257] At least one of the components, elements, modules or units
represented by a block in
the drawings may be embodied as various numbers of hardware, software and/or
firmware structures that execute respective functions described above,
according to an
exemplary embodiment. For example, at least one of these components, elements,
modules or units may use a direct circuit structure, such as a memory,
processing,
logic, a look-up table, etc. that may execute the respective functions through
controls
of one or more microprocessors or other control apparatuses. Also, at least
one of these
components, elements, modules or units may be specifically embodied by a
module, a
program, or a part of code, which contains one or more executable instructions
for
performing specified logic functions, and executed by one or more
microprocessors or
other control apparatuses. Also, at least one of these components, elements,
modules or
units may further include a processor such as a central processing unit (CPU)
that
performs the respective functions, a microprocessor, or the like. Two or more
of these
components, elements, modules or units may be combined into one single
component,
element, module or unit which performs all operations or functions of the
combined
two or more components, elements, modules or units. Also, at least part of
functions of
at least one of these components, elements, modules or units may be performed
by
another of these components, elements, modules or units. Further, although a
bus is not
illustrated in the above block diagrams, communication between the components,
elements, modules or units may be performed through the bus. Functional
aspects of
the above exemplary embodiments may be implemented in algorithms that execute
on
one or more processors. Furthermore, the components, elements, modules or
units rep-
resented by a block or processing steps may employ any number of related art
techniques for electronics configuration, signal processing and/or control,
data
processing and the like.
[258] The above-described methods and operations or steps for the methods
may also be
implemented as a computer readable code in a computer readable recording
medium.
The computer readable recording medium is any data storage device capable of
storing
data which is readable by a computer system. Examples of the computer readable
CA 3022469 2018-10-29
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recording medium may include a read-only memory (ROM), a random-access memory
(RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices,
and
carrier waves (such as data transmission through the Internet). The computer
readable
recording medium may also be distributed through computer systems connected
through a network, and as a result, the computer readable code is stored and
executed
in a distribution method. Further, functional programs, codes, and code
segments for
achieving the exemplary embodiments can be easily analyzed by programmers
skilled
in the art to which the present disclosure is applied.
[259] Further, it can be seen that the apparatus and the method according
to the exemplary
embodiments can be implemented by hardware, software, or a combination of the
hardware and the software. Predetermined software may be stored in a volatile
or non-
volatile storage device, such as ROM, a memory, such as RAM, a memory chip, a
device, or an integrated circuit, or a storage medium, such as a CD, a DVD, a
magnetic
disk, or a magnetic tape, which may optically or magnetically records data and
is si-
multaneously readable by a machine (e.g. a computer), regardless of whether
the pre-
determined software is deletable or rewritable. The methods or operations of
the
methods described above can be implemented by a computer or a portable
terminal
including a controller and the memory and it can be seen that the memory is
one
example of a program including instructions implementing the exemplary em-
bodiments or the machine readable storage medium which is suitable for storing
programs.
[260] Accordingly, the exemplary embodiments includes a program including a
code for
implementing an apparatus and a method described in any claims of the
specification
and a machine (computer) readable storage medium storing the program. Further,
the
program may be electronically carried through any medium such as a
communication
signal transferred through wired or wireless connection and the present
disclosure ap-
propriately includes equivalents thereto.
[261] Further, the apparatuses according to the exemplary embodiment can
receive and
store a program from a program providing device connected in a wired or
wireless
method. A program providing device may include a program including
instructions
that allow a program processing device to perform a predetermined content
protecting
method, a memory for storing information necessary for the content protecting
method,
a communicator for performing wired or wireless communication with a graphic
processing device, and a controller for transmitting a corresponding program
to a
transmission/reception device automatically or according to a request of the
graphic
processing device.
[262] Meanwhile, the detailed exemplary embodiments have been described in
the Detailed
Description, but various modifications can be made without departing from the
scope.
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Therefore, the scope should not be limited to the exemplary embodiment and
should be
defined by the appended claims and equivalents to the appended claims.
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