KR20140052852A - Apparatus and method for transmitting broadcast - Google Patents

Abstract

The present invention relates to a broadcasting transmission apparatus. Disclosed in the present specification is the broadcasting transmission apparatus which comprises an ATSC signal generation unit to transmit an ATSC signal in accordance with ATSC transmission standards; a low-speed data signal generation unit which has the same frequency range as that of the ATSC signal, and transmits at least one narrow-band signal located in a null frequency domain of an NTSC removal filter; a coupling unit to couple the ATSC signal to the at least one narrow-band signal; and an RF transmission unit to transmit the signal, coupled by the coupling unit, as an RF signal.

Description

[0001] Apparatus and Method for Transmitting Broadcast [

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless communication, and more particularly, to a broadcast transmission apparatus and method.

Broadcasting services have commercial nature and public interest in character. As a part of the public service, all broadcasting standards including ATSC specify functions for disaster broadcasting services, and disaster broadcasting service through ATSC-M / H, which is a mobile broadcasting standard of ATSC, has been implemented recently. However, such a conventional disaster broadcast service is available only during reception of a broadcast service through a receiver. Considering the importance and urgency of a disaster broadcast, even in the case of a receiver in a stand-by mode, it is necessary to awaken from a standby mode and provide a disaster broadcast service to viewers when receiving a disaster broadcast. However, in the conventional ATSC standard, the receiver intermittently wakes up from the standby mode and performs signal processing such as synchronization, channel equalization, demodulation, and channel decoding on the entire broadcast signal received in the 6 MHz bandwidth, . Therefore, the receivers supporting the disaster broadcasting service are consuming a large amount of power in the standby mode. Particularly, in the case of a mobile receiver in which battery performance is important, the problem of power consumption is more serious.

Accordingly, there is a need in the art to provide a broadcast service capable of effectively transmitting a simple control signal such as a disaster broadcast to existing ATSC broadcast data.

SUMMARY OF THE INVENTION The present invention provides a broadcast transmitting apparatus and method.

It is another object of the present invention to provide an apparatus and method for additionally providing low-speed data such as a simple control signal to existing ATSC broadcast data.

According to one aspect of the present invention, a broadcast transmission apparatus is provided. The broadcast transmission apparatus includes an ATSC signal generator for transmitting an ATSC signal according to an ATSC transmission standard, at least one narrowband signal having a frequency range equal to that of the ATSC signal and located in a null frequency region of an NTSC rejection filter, A low speed data signal generator for transmitting the ATSC signal and the at least one narrowband signal, and an RF transmitter for transmitting a signal combined by the combining unit as an RF signal.

According to the present invention, it is possible to provide a method and apparatus capable of further transmitting low-speed data without affecting the performance of a terrestrial or mobile ATSC receiver.

In addition, wake-up control for a receiver for a disaster broadcast can be effectively implemented by combining with a conventional ATSC broadcast signal.

1 is a structural diagram of a broadcast transmission apparatus to which an embodiment of the present invention can be applied.
2 is a diagram illustrating an effect of eliminating interference through an NTSC interference cancellation filter of a broadcast transmission apparatus to which an embodiment of the present invention can be applied.
3 is a structural diagram of a structure of an NTSC interference cancellation filter of a broadcast receiver to which an embodiment of the present invention can be applied.
4 is a structural diagram of a broadcast transmission apparatus according to an embodiment of the present invention.
5 is a structural diagram of an ATSC signal generation unit of the present invention.
6 shows a spectrum of an ATSC signal generated through an ATSC signal generator according to an embodiment of the present invention.
7 shows a spectrum of a signal generated through a low-speed data signal generator according to an embodiment of the present invention.
8 is a flowchart of a broadcast transmission method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings.

1 is a structural diagram of a broadcast transmission apparatus to which an embodiment of the present invention can be applied.

According to A / 53 Part 2, a transmission standard established by the Advanced Television System Committee (ATSC), a standardization organization for digital TV broadcasting in the United States, when an 8-VSB modulation scheme is used, an RS (Reed-Solomon) Level symbols after applying interference filter pre-coding and Trellis coding to a bit stream subjected to interleaving (convolutional interleaving) as shown in FIG. The interference filter pre-coding is intended to prevent ATSC signal reception performance from being greatly degraded due to interference of existing NTSC analog signals when an existing NTSC analog signal is received on the same channel as the ATSC signal. That is, in an area where co-channel interference due to the NTSC analog signal is expected, the ATSC signal can be transmitted by 28.615 kHz higher than the center frequency of the channel allocated to the transmitter as shown in FIG. The receiver can configure an NTSC interference rejection filter having the same form as the interference filter pre-coding used in the transmitter.

3 is a structural diagram of a structure of an NTSC interference cancellation filter of a broadcast receiver to which an embodiment of the present invention can be applied.

When the NTSC interference cancellation filter is used, a video carrier, a chroma subcarrier, and an audio carrier signal of an NTSC analog signal are positioned near null of an NTSC rejection filter. The effect of eliminating the NTSC analog interference signal can be obtained simply.

The interference filter pre-coder is applied to the transmitter in the same manner as the NTSC elimination filter of the receiver, as configured to prevent the NTSC elimination filter of the receiver from hindering the restoration performance of the ATSC broadcast data.

As described above, the ATSC standard basically includes interference filter pre-coding considering co-channel interference from an NTSC analog signal. Thus, all ATSC receivers include an NTSC rejection filter, as is the ATSC-M / H standard (document number: A / 153), which is designed to be compatible with A / 95 as well as terrestrial television conforming to the A / 53 standard.

However, it is not necessary to eliminate the NTSC interference of the interference filter pre-encoder included in the ATSC standard in the trend of stopping the analog terrestrial TV broadcasting and switching the digital TV broadcasting worldwide in recent years. In particular, ATSC USA succeeded in the digital conversion of nationwide terrestrial TV broadcasting in June 2009, so there is no same channel interference problem caused by NTSC analog TV broadcasting. Korea is also in the same situation as the US after the digital transition of TV broadcasting in 2012. However, there is almost no influence on the transmission performance depending on the presence or absence of the interference filter pre-coding. Particularly, since the conventional ATSC receivers already applied have the NTSC elimination filter applied thereto, there is no need to change the ATSC standard even after the digital conversion and there is no need to replace the receiver.

4 is a structural diagram of a broadcast transmission apparatus according to an embodiment of the present invention.

The broadcast transmitting apparatus according to an embodiment of the present invention includes an ATSC signal generating unit 41, a low speed data signal generating unit 43, a combining unit 45, and an RF transmitting unit 47.

The ATSC signal generation unit 41 generates a signal according to the ATSC transmission standard A / 53 Part 2. The concrete structure of the ATSC signal generator 41 is shown in FIG. 5, and the spectrum of the ATSC signal that has undergone the signal processing of the ATSC signal generator 41 is as shown in FIG.

The transmission frequency of the ATSC signal may have a center frequency shifted by a specific frequency interval from the center frequency of a channel allocated to the transmitter as required, as shown in FIG. In the spectrum shown in FIG. 2, it is expressed as having 28.615 kHz, but it is also possible to have other center frequency offsets.

The low-speed data signal generator 43 outputs a low-speed data signal having the spectrum shown in FIG. 7, the low-speed data signal generator 43 may simultaneously transmit five narrow-band signals within one broadcast channel bandwidth having the same frequency range as the ATSC signal. In addition, if necessary, up to seven narrow-band spectrums can be simultaneously transmitted using an additional narrow-band spectrum at both ends of five narrow-band signals, or a narrow-band signal consisting of only a part of the five narrow- . The narrowband signal constituting the low-speed data signal spectrum generated by the low-speed data signal generator 43 can be generated using various techniques, not limited to the specific scheme, such as channel coding and modulation.

6 and 7 have the same frequency range, and when a specific frequency offset is applied to the ATSC signal, the same frequency offset is applied to the low-speed data signal.

In FIG. 7, the dotted line between the five narrowband signals is a log scale representation of the gain of the NTSC rejection filter of the receiver. As shown in the figure, the signal transmitted by the low-speed data signal generator 43 is a null region of the NTSC elimination filter or a narrowband signal of a level at which the influence thereof can be sufficiently suppressed by the NTSC elimination filter of the ATSC receiver. It is located at a frequency close enough to the null region and transmitted.

Accordingly, by utilizing the NTSC elimination function of the existing ATSC receivers, it is possible to transmit low-speed data such as simple control signals other than the ATSC broadcast data without affecting the operation of the existing ATSC receiver.

Referring again to FIG. 4, the output of the signal generated through the VSB modulator of the ATSC signal generator 41 may be a baseband signal having a complex value, or may be an IF signal having a real value. When the output of the VSB modulator is a baseband signal, the low-speed data signal generator 43 also outputs a baseband signal. When the output of the ATSC generator 41 is an IF signal, the low-speed data signal generator 43 ) Also outputs an IF signal.

The combining unit 45 combines the signal generated by the ATSC signal generating unit 41 and the signal generated by the low-speed data signal generating unit 43.

The RF transmitter 47 converts the baseband signal or the IF signal output from the combiner 45 into an RF signal having a frequency corresponding to the broadcast channel assigned to the transmitter, and transmits the RF signal. The RF transmitter 47 transmits a signal through a transmission antenna, and can transmit a signal by applying a specific frequency offset as needed.

The broadcast transmission apparatus having the above configuration can transmit low-speed data such as a simple control signal other than the ATSC broadcast data without affecting the operation of the existing ATSC receiver by utilizing the NTSC elimination function of the existing ATSC receivers.

8 is a flowchart of a broadcast transmission method according to an embodiment of the present invention.

The broadcast transmission method according to the present invention first generates an ATSC signal (S81). The ATSC signal generates a signal according to the ATSC transmission standard A / 53 Part 2, and the spectrum of the ATSC signal is as shown in FIG. The transmission frequency of the ATSC signal may have a center frequency shifted by a specific frequency interval from the center frequency of a channel allocated to the transmitter as required, as shown in FIG. In the spectrum shown in FIG. 2, it is expressed as having 28.615 kHz, but it is also possible to have other center frequency offsets.

Next, a low-speed data signal is generated (S83). The low-speed data signal outputs a low-speed data signal having the spectrum shown in FIG. The generated low-speed data signal may be five narrow-band signals simultaneously transmitted within one broadcast channel bandwidth having the same frequency range as the ATSC signal. Further, a maximum of 7 narrow-band spectrums may be simultaneously transmitted using an additional narrow-band spectrum at both ends of five narrow-band signals as required, and a narrow-band signal consisting of only a part of the five narrow- May be transmitted. The transmitted low-rate data signal may be generated using various techniques such as channel coding, modulation, and the like, without being limited to a specific scheme. The generated ATSC signal and low-speed data signal have the same frequency range, and when a specific frequency offset is applied to the ATSC signal, the same frequency offset is applied to the low-speed data signal.

Next, the generated ATSC signal and the low-speed data signal are combined (S85). The output of the ATSC signal may be a baseband signal having a complex value, or may be an IF signal having a real value. When the output of the VSB modulator is a baseband signal, the low-speed data signal also outputs a baseband signal. When the ATSC signal is an IF signal, the low-speed data signal also outputs an IF signal. Thus, the signal to be combined may also be a baseband signal or an IF signal.

Finally, the combined signal is RF transmitted (S87). The RF transmitter 47 converts the combined baseband signal or the IF signal into an RF signal having a frequency corresponding to a broadcast channel assigned to the transmitter, and transmits the RF signal. The RF transmitter 47 transmits a signal through a transmission antenna, and can transmit a signal by applying a specific frequency offset as needed.

According to the broadcast transmission method, low-speed data such as a simple control signal other than the ATSC broadcast data can be transmitted without affecting the operation of the existing ATSC receiver by utilizing the NTSC elimination function of the existing ATSC receivers.

Claims (1)

In a broadcast transmission apparatus,
An ATSC signal generation unit for transmitting an ATSC signal according to an ATSC transmission standard;
A low-speed data signal generator for transmitting at least one narrowband signal having the same frequency range as the ATSC signal and located in a null frequency region of the NTSC elimination filter;
A combining unit for combining the ATSC signal and the at least one narrowband signal; And
An RF transmitter for transmitting a signal coupled by the coupling unit as an RF signal;
And transmitting the broadcast signal.

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