KR101215492B1 - Apparatus for detecting broadcast signal, and method for the same - Google Patents

Abstract

The present invention relates to a technique for detecting a broadcast signal at high speed in a DAB / T-DMB system. In particular, the present invention calculates a signal-to-noise ratio (SNR) using a power value and an energy correlation value with respect to a received signal, thereby presenting a broadcast signal. Disclosed is a technique for detecting a broadcast signal at high speed in a DAB / T-DMB system by determining the presence or absence. The broadcast signal detection method of the present invention includes calculating a signal power value for a sample corresponding to a correlation length for a plurality of received samples, and applying the first and second correlation lengths apart by a correlation offset for the plurality of received samples. Calculating an energy correlation value for a corresponding sample, calculating a signal-to-noise ratio based on the signal power value and the energy-correlation value, and comparing the signal-to-noise ratio with a predetermined threshold to determine the presence or absence of a broadcast signal, If it is determined that the noise ratio is greater than or equal to a predetermined threshold, determining that a broadcast signal exists. According to the present invention, since the existence of a valid broadcast signal is determined before the synchronization is performed, the presence or absence of a broadcast signal is determined, and synchronization is performed only when there is a broadcast signal, thereby greatly reducing the synchronization time.

Description

Broadcast signal detection apparatus and method {APPARATUS FOR DETECTING BROADCAST SIGNAL, AND METHOD FOR THE SAME}

The present invention relates to a technique for detecting a broadcast signal at high speed in a DAB / T-DMB system. In particular, the present invention calculates a signal-to-noise ratio (SNR) using a power value and an energy correlation value with respect to a received signal, thereby presenting a broadcast signal. Disclosed is a technique for detecting a broadcast signal at high speed in a DAB / T-DMB system by determining the presence or absence.

In analog audio broadcasting, the quality of received signal is drastically deteriorated when the receiver is moved, and it uses high transmit power to reduce the influence of noise, so it is not power efficient, and uses different frequencies in the neighboring area to avoid interference between channels. Because of this, there is a technical limitation of poor spectral efficiency. Accordingly, researches on digital audio broadcasting that can replace conventional AM and FM radio broadcasting have been conducted. Digital audio broadcasting (DAB) is a standard developed in Europe for this purpose.

Digital audio broadcasting is a multimedia broadcasting not only capable of transmitting audio of various channels made of high quality, but also providing various additional data and transmitting still images, videos, and graphics. Examples of multimedia services that can be provided by digital audio broadcasting include programs for providing travel and traffic information, showing headline text and images of news, or combining weather forecast and traffic information with electronic maps. Interlocking information provision services, independent information services independent of programs such as website broadcasting or GPS for DAB, and video transmission services. In order to provide and receive various services stably even when moving, an Orthogonal Frequency Division Multiplexing (OFDM) transmission scheme is used in which performance deterioration is reduced substantially without influence of multipath fading.

T-DMB is a broadcasting system that can additionally provide high-definition multimedia services while using the same physical layer as DAB. In other words, T-DBM is a new digital broadcasting system that enables the reception of a variety of multimedia services such as audio, video, data to the mobile receiver. Accordingly, DAB / T-DMB is one of the digital broadcasting systems that are attracting attention because it is possible to enjoy high-quality high-definition broadcasting through a personal portable terminal or a vehicle terminal on the go.

In general DAB / T-DMB broadcasting, since the broadcast service can be normally received after the reception of the broadcast configuration information, it is necessary to complete the synchronization process as soon as possible. However, most of the time spent in the synchronization process occurs during frame synchronization. The reason is that the frame synchronization is performed in the null symbol section in the frame, but if the frame synchronization is not performed, it takes considerable time to finally check whether there is a valid broadcast signal because the frame synchronization is continuously performed for a predetermined time. Because.

Therefore, a technique for quickly determining whether a valid broadcast signal exists in a received signal is desired.

An object of the present invention for solving the above problems is to provide a technique for quickly detecting a signal to determine the existence of a valid broadcast signal before performing synchronization in the DAB / T-DMB broadcasting system.

In accordance with another aspect of the present invention, there is provided a broadcast signal detecting method comprising: calculating signal power values for a sample corresponding to a correlation length with respect to a plurality of received samples; Calculating an energy correlation value for samples corresponding to the first and second correlation lengths apart by a correlation offset for the plurality of received samples; Calculating a signal-to-noise ratio based on the signal power value and the energy correlation value and comparing the signal-to-noise ratio with a predetermined threshold value to determine the presence or absence of a broadcast signal; And determining that the broadcast signal exists when it is determined that the signal to noise ratio is equal to or greater than a predetermined threshold.

In addition, the apparatus for detecting broadcast signals according to the present invention includes a power calculation unit for calculating a signal power value for a sample corresponding to a correlation length with respect to a plurality of received samples; An energy correlation calculation unit configured to calculate an energy correlation value for a sample corresponding to the first and second correlation lengths separated by a correlation offset with respect to the plurality of received samples; The signal-to-noise ratio is calculated based on the signal power value and the energy correlation value, the presence or absence of a broadcast signal is determined by comparing the signal-to-noise ratio with a predetermined threshold value, and when the signal-to-noise ratio is determined to be greater than or equal to the predetermined threshold value, the broadcast signal exists. It is configured to include; signal determination unit for determining that.

In case of using the broadcast signal detection technology according to the present invention as described above, before the synchronization is performed in the DAB / T-DMB broadcasting system, the presence or absence of a broadcast signal is determined by determining the presence or absence of a valid broadcast signal based on the broadcast configuration information. Since the synchronization is performed only when there is a broadcast signal, the synchronization time can be significantly reduced.

1 is a flowchart illustrating a general broadcast information receiving process;
2 is a view showing the structure of a DAB frame according to the present invention;
3 is a diagram showing an OFDM symbol structure according to the present invention;
4 is a view showing the internal structure of a DAB system according to the present invention;
5 is a view showing the internal structure of a signal detection apparatus according to an embodiment of the present invention;
6 is a diagram illustrating a method of calculating an energy correlation value by an energy correlation calculation unit of a signal detection apparatus according to an embodiment of the present invention;
7 is a flowchart illustrating a signal detection process according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, A, B, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

Prior to describing a signal detection technique according to an embodiment of the present invention, a representative synchronization method at a receiving end for receiving broadcast information will be described with reference to FIG. 1.

1 shows a general broadcast information receiving process.

Referring to FIG. 1, the receiver performs frame synchronization on a null symbol interval on a sync channel of a frame to search for a starting point of the frame approximately (S101), and when frame synchronization is completed (S102), the reference on the sync channel is determined. Subcarrier frequency synchronization is performed in the symbol period (S103). In this case, the length of the frame is changed according to the DAB transmission mode, and the receiver performs frame synchronization only on the null symbol interval on the synchronization channel of the frame. If the receiving end searches for the start point of the frame in the null symbol interval (S102), the frequency synchronization is performed without performing resynchronization (S103). However, when the receiving end does not search for the start point of the frame in the null symbol period (S102), frame synchronization for searching for the start point of the frame is continuously performed for a predetermined time (S104) (S101).

That is, in a strong electric field region or a frequency band in which a broadcast signal does not exist, the receiving end may complete a frame synchronization task within a length of the frame. However, in a weak field or a frequency band in which a broadcast signal does not exist, the receiving end consumes a relatively long time for frame synchronization.

The receiver performs frequency synchronization (S103) and when frequency synchronization ends (S105), it performs decoding on a fast information channel (S106). Thereafter, when the receiving end completes the reception of the broadcast information (S107), it may normally receive the broadcast service (S109). On the other hand, when the receiving end is not completed (S107), the receiving end performs decoding on the fast information channel until the predetermined broadcast information receiving time ends (S108) (S106). At this time, when the predetermined broadcast information reception time ends, the receiver cannot normally receive a broadcast service (S110).

As such, since a receiving end receiving general broadcast information performs frame synchronization on a null symbol interval on a sync channel of a frame, there is a problem in that it takes a considerable time to finally confirm whether a valid broadcast signal exists in the received signal. In addition, when auto-tuning all frequency bands allocated for DAB / T-DMB instead of one frequency band, the total operation time will be further increased and the user inconvenience will be worsened. Next, the structure of the DAB frame according to the present invention will be described with reference to FIG. 2.

2 shows the structure of a DAB frame according to the present invention.

Referring to FIG. 2, a DAB transmission frame structure includes OFDM symbols received from a digitized I / Q interface or an IF interface in transmission frame units. One transmission frame is composed of three channels: a synchronization channel (SC) 201, a fast information channel (FIC) 203, and a main service channel (MSC) 205. According to the number of fast information blocks (FIBs) and common interleaved frames (CIFs), four transmission modes are classified as shown in Table 1.

The DAB uses a double quadrature phase shift keying (DQPSK) modulation scheme for OFDM transmission based on the Eureka-147 DAB. DQPSK modulation is a 45-degree shift in data transmission and transmits the same phase based on the previous value. In other words, two values of 0 and 1 represent four values of 45 (0,0), 135 degrees (1,0), 255 degrees (1,1), and 315 degrees (0,1). It is sent in gray code to facilitate error detection.

In addition, four transmission modes are configured as shown in <Table 1> .In Korea, among the four transmission modes, transmission mode 1 suitable for the VHF channel is used, and transmission modes 2 to 4 are applied in Europe and other countries. It is a mode. At this time, the length of the frame and the guard interval size are determined according to each transmission mode.

The synchronization channel 201 is composed of a null symbol 211 and a phase reference symbol (PRS) 231, which are fundamental to transmission frame synchronization, automatic frequency control, channel state estimation, and transmitter identification. Used for demodulation function. During the null symbol period, no signal may be transmitted without transmitting data, or a transmitter identification information (TII) signal may be transmitted. The phase reference symbol is used for automatic encoding because a specific pattern is fixed for each transmission mode. The phase reference symbol is a reference signal for demodulating the DQPSK signals of the FIC and the MSC, and modulates and transmits a specific signal pattern.

The fast information channel 203 is a channel used for accessing fast information of the receiver. The fast information channel is composed of FIBs that carry control information describing the structure of the primary service channel. Unlike the MSC, the fast information channel requires fast access and thus does not apply time axis interleaving. The FIB is 256 bits and contains three or four pieces of information related to one CIF depending on the transmission frame mode. Control information included in the FIB includes multiplex configuration information (MIC) that provides multiplexing information, service information, conditional access management information, and optional data information.

When the high speed information channel 203 is the stream mode for the two transmission modes of the main service channel 205, if only the connection information of the service and the subchannel is provided in the MCI information, the service and the service element are connected to enable the configuration of the service. do. On the other hand, in the packet mode, unlike the stream mode, the service configuration is possible only by including the connection information between the service element and the service element in the MCI as well as the connection information of the service element and the subchannel including the service element.

The primary service channel 205 is a time-base interleaving data channel and consists of CIFs carrying multimedia data. One CIF is 55926 bits, generated every 24ms, and divided into several subchannels. Each subchannel carrying a service element is error-protected by individual convolutional coding and has a stream mode and a packet mode according to the service element inclusion relationship of the subchannel.

The stream mode is a mode in which each service element constituting a service is carried through one subchannel, and the packet mode is a mode in which several different service elements packetized in one subchannel are carried. In the packet mode, up to 1023 service elements may be included in one subchannel, and each packet is subjected to a cyclic redundancy check (CRC) to detect a transmission error, and a repetition function is applicable to the packet. It is more resistant to transmission error than mode.

On the other hand, the number of OFDM symbols in one frame varies depending on the transmission mode as shown in Table 1. The OFDM symbols of the frame corresponding to transmission mode 1 are composed of symbol counters from 0 to 76. As a counter for constituting OFDM symbols, the maximum value is changed according to each mode, and the null symbol is always zero.

Frame sync serves to find the starting point of a DAB frame. In the frame synchronization process, first, a frame offset search interval for estimating a frame offset value and a frame offset compensation interval required for applying a frame offset value estimated through the search interval are required. In general, the search interval is at least one frame and the null symbol 211 interval. In the search section, a power-moving average method using two windows is generally used. Next, the OFDM symbol structure according to the present invention will be described in more detail with reference to FIG. 3.

3 shows an OFDM symbol structure according to the present invention.

Transmission of the OFDM symbol is processed in units of blocks. While an OFDM symbol is transmitted on a multipath channel, it is affected by previously transmitted symbols. In order to prevent such interference between OFDM symbols, a transmitter inserts a guard interval (GI) between consecutive OFDM blocks. At this time, block B 301, which is the last part of the OFDM signal, is copied and block A 303 is inserted as a guard interval. At this time, the length of the guard interval 303 should be longer than the channel delay spread of the radio channel.

The length of the guard interval 303 depends on the transmission mode of <Table 1>. The protection interval is 246us when the transmission mode is 1, the protection interval is 62us when the transmission mode is 2, and the protection interval when the transmission mode is 3. Is 31us, and if the transmission mode is 4, the guard interval is 123us. Next, the DAB system according to the present invention will be described in more detail with reference to FIG. 4.

4 shows the internal structure of a DAB system according to the invention.

Referring to FIG. 4, a DAB system includes a transmitter 400 and a receiver 500, and the transmitter 400 transmits not only basic audio service data but also video service data and additional service data. Therefore, an audio service encoder 401, a video service encoder 431, and an additional service encoder 451 are provided. Audio service data such as voice and music to be broadcasted are input to the audio service encoder 401, encoding and channel coding are performed, and then input to the main service multiplexer 403. Since a plurality of audio services are possible in the DAB system, a plurality of audio service encoders 401 may exist.

Data such as text information, web information, etc. except audio are classified into packet mode data, and the packet mode data is input to the additional data service encoder 451, and encoding and channel coding are performed, and then input to the main service multiplexer 403. do. Since a plurality of packet mode data services may exist, a plurality of additional data service encoders 451 may also exist.

The signal constituting the video service at the data transmitter includes an audio signal, a video signal, and an additional data signal. Video service data, including video signals such as movies, dramas and videos, and additional data associated with them, such as subtitle data, text information, traffic information, and data classified into packet mode data of the DAB standard such as still images, are stream mode data. The data is sent to the video service encoder 431, encoded into stream mode data, and then input to the main service multiplexer 403 through channel coding.

The main service multiplexer 403 multiplexes the audio service, packet mode data, and stream mode data service on the main service channel, adds additional information and multiplexing information about each service, and attaches synchronization information thereto to create a DAB transmission frame. Output The DAB transmission frame thus made is transmitted to the receiver by being propagated in the VHF band through the OFDM modulator 405 and the amplifier 407. In this case, the receiving end 500 may be any of a fixed type, a portable type, and a mobile type. Next, the internal structure of the signal detection apparatus according to the exemplary embodiment of the present invention, which is inserted into the receiver 500 and detects a valid signal before synchronization, will be described in detail with reference to FIG. 5.

5 shows an internal structure of a signal detection apparatus according to an embodiment of the present invention.

In the embodiment of FIG. 5, the signal detecting device [FIG. 4] may be inserted together between the RF tuner and the ADC and the synchronization unit, and in FIG. 5, only components of the signal detecting device may be schematically illustrated. Figure is shown. The signal detection apparatus 500 for this purpose may include a power calculator 505, an energy correlation calculator 507, and a signal determiner 509.

Although not shown in FIG. 5, the RF tuner selectively receives a DAB / T-DMB signal through an antenna. In this case, the DAB / T-DMB signal may selectively receive broadcast information. The antenna input for the RF tuner receiving the DAB / T-DMB signal may be equipped with a DAB / T-DMB dedicated antenna, and may optionally receive a conventional terrestrial TV antenna input. Currently, RF bands of domestic terrestrial DMB service use bands 8 and 12 of VHF band, so it is possible to receive DAB / T-DMB data through existing terrestrial TV antenna. The ADC converts the analog signal into a digital signal with respect to the sample input through the RF tuner and is input to the power calculator 505 and the energy correlation calculator 507 of the signal detection apparatus.

Referring to FIG. 5, the power calculator 505 calculates a signal power value for a sample that is a converted signal digitized by an ADC. The power calculator 505 may calculate a signal power value using Equation 1.

Referring to Equation 1, x (n) represents a sample converted into a digital signal by the ADC 503, and Ns represents a correlation depth. n represents the sample length.

The energy correlation calculation unit 507 receives a sample converted into a digital signal by the ADC 503 and calculates an energy correlation value for the sample. In this case, the energy correlation calculator 507 may calculate an energy correlation value for the sample by using Equation 2.

Referring to Equation 2, N _FFT represents a correlation offset and Ns represents a correlation length. N represents the sample length. Where x (·) represents a sample converted into a digital signal by the ADC 503 and Rcorr is an energy correlation value obtained from this sample.

The signal determination unit 509 receives the power of the signal previously calculated by the power calculation unit 505, and receives the energy correlation value calculated by the energy correlation calculation unit 507. Then, the signal determination unit 509 calculates a signal-to-noise ratio (SNR) using the signal power value and the energy correlation value. The signal determination unit 509, which calculates the signal-to-noise ratio, compares the calculated signal-to-noise ratio with a predetermined threshold to determine the presence or absence of a broadcast signal.

When the signal determining unit 509 determines that the calculated signal-to-noise ratio is equal to or greater than a predetermined threshold value, the broadcast signal is present. On the other hand, when the signal determining unit 509 determines that the calculated signal-to-noise ratio is not greater than or equal to a predetermined threshold value, the broadcast signal does not exist. In this case, the signal determination unit 509 may calculate the signal-to-noise ratio using Equation (3).

Referring to Equation 3, R _corr represents an energy correlation value received after being calculated by the energy correlation calculation unit 507, and P is a signal power value received after being calculated by the power calculation unit 505. Indicates.

At this time, when the signal determining unit 509 determines that a broadcast signal exists, the synchronization unit (not shown) searches for frame synchronization, that is, the start point of the DAB frame. At this time, the synchronization unit searches for the start point of the frame using the signal characteristics of the null symbol in the null symbol period of the frame, and the synchronization unit for searching the start point of the frame performs frequency synchronization of the subcarriers in the PRS symbol period. Thereafter, the decoder (not shown) may perform decoding on the fast information channel and normally receive a broadcast service when the broadcast configuration information is received through decoding on the fast information channel. Next, a process of calculating an energy correlation value by the energy correlation calculation unit of the signal detection apparatus according to an embodiment of the present invention will be described with reference to FIG. 6.

6 illustrates a method of calculating an energy correlation value by an energy correlation calculation unit of a signal detection apparatus according to an embodiment of the present invention.

Referring to FIG. 6, the energy correlation calculator 507 calculates an energy correlation value by a correlation length for a correlation offset corresponding to each transmission mode in order to detect a signal for four transmission modes of a DAB. . For example, the correlation length is set to 63, which is the length of the guard interval of transmission mode 3 having the shortest guard interval among four transmission modes of the DAB, and the correlation offset is a Fast Fourier Transform (FFT) size for each transmission mode. Set to 2048, 512, 256 and 1024 which are the same as In this case, when the transmission mode is 1, the protection period is 246us when the transmission mode is 1, the protection period is 62us when the transmission mode is 2, the protection period is 31us when the transmission mode is 3, and the protection mode is 4 when the transmission mode is 4. The guard interval is 123us.

The energy correlation calculation unit 507 is a sample corresponding to Pre-N _s 601, which is a first correlation length apart from each other by a correlation offset, for the N samples, and Post N _s 602, which is a second correlation length. Calculate the energy correlation for the corresponding sample. Next, a signal detection process according to an embodiment of the present invention will be described in more detail with reference to FIG. 7.

7 illustrates a signal detection process according to an embodiment of the present invention.

Although not shown in FIG. 7, the plurality of samples input to the signal detection apparatus may be configured to selectively receive a DAB / T-DMB signal through an antenna by an RF tuner, and to provide an analog signal with respect to a sample input through an RF tuner. It converts into a digital signal and shows the signal input to the signal detection apparatus.

Referring to FIG. 7, the signal detecting apparatus calculates a signal power value of a sample corresponding to a correlation length with respect to a plurality of received samples (S701). The signal detecting apparatus calculates an energy correlation value for samples corresponding to the first and second correlation lengths apart by a correlation offset for the plurality of received samples (S702).

The signal detecting apparatus calculates a signal-to-noise ratio based on the signal power value and the energy correlation value, and compares the signal-to-noise ratio with a predetermined threshold value to determine the presence or absence of a broadcast signal (S703). If the signal detection apparatus determines that the signal-to-noise ratio is greater than or equal to the predetermined threshold value, it is determined that a broadcast signal exists (S704). On the other hand, when the signal detection apparatus determines that the signal-to-noise ratio is not greater than or equal to the predetermined threshold, it is determined that the broadcast signal does not exist (S705). Although not shown in FIG. 7, the signal detecting apparatus performs decoding after performing a frame synchronization process and a frequency synchronization process as shown in FIG. 1 only after determining that a broadcast signal exists. If the broadcast configuration information is received through decoding on the fast information channel, the broadcast service can be normally received.

Accordingly, before the synchronization is performed, the presence or absence of a valid broadcast signal is determined based on the broadcast configuration information to determine whether there is a broadcast signal, and synchronization is performed only when there is a broadcast signal. There are advantages to it.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

400: transmitting end 401: audio service encoder
431 video service encoder 451 additional service encoder
403: main service multiplexer 405: OFDM modulator
407: amplifier 500: receiving end
505: power calculation unit 507: energy correlation calculation unit
509: signal determination unit

Claims (12)

Calculating a signal power value for a sample corresponding to a correlation length with respect to the plurality of received samples;
A second step of calculating an energy correlation value for a sample corresponding to the first and second correlation lengths separated by a correlation offset with respect to the plurality of received samples using Equation 2 below;
&Quot; (2) &quot;

(Where x (ni) is a plurality of samples, R _corr (n) is an energy correlation value, N _FFT is a correlation offset, Ns is a correlation length, and N is a sample length)
Calculating a signal-to-noise ratio for the sample based on the signal power value and the energy correlation value;
A fourth step of determining whether a broadcast signal exists by comparing the signal to noise ratio with a predetermined threshold value;
A fifth step of determining that a broadcast signal exists in the received sample when it is determined that the signal to noise ratio is equal to or greater than a predetermined threshold value;
Broadcast signal detection method comprising a.
The method according to claim 1,
If it is determined that the signal to noise ratio is less than or equal to a predetermined threshold, determining that no broadcast signal exists in the received sample;
Broadcast signal detection method further comprises.
The method according to claim 1,
Performing frame synchronization by searching for a start point of a frame in a null symbol interval on a sync channel of the frame according to the determination result;
Performing frequency synchronization of a subcarrier on a reference symbol interval on a synchronization channel on which the frame synchronization is performed;
Broadcast signal detection method further comprises.
The method according to claim 3,
The first step is a broadcast signal detection method, characterized in that for calculating the signal power value using the equation (1).
&Quot; (1) &quot;

Where x (n) is a plurality of samples, Ns is the correlation length and n is the sample length.
delete The method of claim 4,
In the third step, the signal-to-noise ratio is calculated using Equation 3 below.
<Equation 3>

Where R _corr is an energy correlation value and P is a signal power value.
A power calculator configured to calculate a signal power value for a sample corresponding to a correlation length with respect to the plurality of received samples;
An energy correlation calculation unit configured to calculate an energy correlation value for a sample corresponding to the first and second correlation lengths separated by a correlation offset with respect to the plurality of received samples using Equation 2 below;
&Quot; (2) &quot;

(Where x (ni) is a plurality of samples, R _corr (n) is an energy correlation value, N _FFT is a correlation offset, Ns is a correlation length, and N is a sample length)
Computing a signal-to-noise ratio based on the signal power value and the energy correlation value, comparing the signal-to-noise ratio with a predetermined threshold to determine the presence or absence of a broadcast signal, and determining that the signal-to-noise ratio is greater than or equal to a predetermined threshold. A signal determination unit determining that a broadcast signal exists;
Broadcast signal detection device comprising a.
The method of claim 7,
And the signal determiner determines that a broadcast signal does not exist when the signal to noise ratio determines that the signal to noise ratio is equal to or less than a predetermined threshold value.
The method of claim 7,
When the broadcast signal is present, frame synchronization is performed by searching for a start point of a frame in a null symbol interval on a sync channel of a frame, and performing frequency synchronization of a subcarrier in a reference symbol interval on a sync channel on which the frame synchronization is performed. A synchronization unit;
Broadcast signal detection device further comprises.
The method according to claim 9,
And the power calculator calculates a signal power value using Equation 1 below.
&Quot; (1) &quot;

Where x (n) is a plurality of samples, Ns is the correlation length and n is the sample length.
delete The method of claim 10,
And the signal determining unit calculates a signal-to-noise ratio using Equation 3 below.
<Equation 3>

Where R _corr is an energy correlation value and P is a signal power value.

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