KR100706621B1 - An identification sign detection device for transmitter identification and its method - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an apparatus for detecting an identification code for transmitter identification and a method thereof.

2. The technical problem to be solved by the invention

The present invention is to detect the identification information for identifying each transmitter after minimizing the in-band digital TV signal interference which has the greatest influence on transmitter identification by using channel equalizer output stage information when constructing a single frequency network composed of multiple transmitters. An object of the present invention is to provide an identification code detecting device and a method thereof.

3. Summary of Solution to Invention

An apparatus for detecting an identification code for transmitter identification, the apparatus comprising: a channel equalizer for compensating a channel by performing a channel equalization process on an output signal from a pilot cancellation unit of a digital TV receiver; A data symbol detector for detecting (restoring) only 8 levels of in-band digital TV signals from the signal that has been channel-equalized in the channel equalizer; A subtractor for removing only an in-band digital TV signal output from the data symbol detector from a signal obtained by performing channel equalization in the channel equalizer; And an identification code detector for detecting transmitter identification information by using a correlation between an output signal of the subtractor and a transmitter unique identification code stored in advance.

4. Important uses of the invention

The present invention is used in digital TV receivers and the like.

Transmitter Identification, Identification Detection, Channel Equalization, In-band Digital TV Signal Rejection

Description

An identification sign detection device for transmitter identification and its method

1 is a configuration of an embodiment of a conventional 8-level residual sideband type digital TV transmitter,

2 is a block diagram of an embodiment of a conventional 8-level residual sideband type digital TV receiver;

FIG. 3 is a block diagram of an embodiment of an 8-level residual sideband type digital TV transmitter using a conventional RF watermark technique.

4 is a diagram illustrating an embodiment of an 8-level residual sideband scheme digital TV receiver using a conventional RF watermark technique for constructing a single frequency network;

5 is a configuration diagram of a digital TV receiver including an apparatus for detecting an identification code for transmitter identification according to the present invention;

6 is a detailed configuration diagram of an embodiment of an identification code detection apparatus for identifying a transmitter according to the present invention;

7 is an exemplary view of an output waveform of an identification code detection apparatus for identifying a transmitter in the presence of white noise;

8 is an exemplary view of an output waveform of an identification code detecting apparatus for identifying a transmitter according to the present invention in the presence of white noise.

* Explanation of symbols for the main parts of the drawings

206: channel equalizer 301: identification code insertion unit

401 identification code detector 501 identification code detection device

601: DTV data detector 602: data symbol detector

603: DTV Data Eliminator

The present invention relates to a digital TV receiver, and more particularly, identification information for identifying each transmitter on the receiver side by using a unique identification code of a transmitter located inside a single frequency network in a single frequency network system composed of multiple transmitters. An apparatus for detecting an identification code and a method for detecting the same.

Recently, technologies for high quality digital TV signal transmission using a network composed of multiple transmitters have been actively studied. There are two methods for constructing a network using multiple transmitters: a multiple frequency network (MFN) system and a single frequency network (SFN) system. One of these frequencies forms a network between multiple transmitters. The single frequency network method is more efficient in terms of frequency use than the multi-frequency network method.

Synchronization Standard for Distributed Transmission in ATSC (Advanced Television System Committee), an American digital transmission standard that uses 8-VSB (8-Vestigial Side Band) as a modulation method (A / 110) is a synchronization standard between multiple transmitters for constructing a single frequency network using distributed transmission. That is, for each transmitter, the transmission part of the ATSC A / 53 standard (Randomizer, Reed Solomon FEC, Byte interleaving, Bit interleaving, Trellis coding) Coding, etc.) to allow transmitters located in a single frequency network cell to transmit the same signal.

Such a single frequency network scheme has a disadvantage in that reception equalization performance is degraded due to strong (0 dB) pre / post ghost and ghost channel delay spreads caused by multiple transmitters. When using a channel equalizer of performance, a wider service area can be formed. In addition, by providing a certain level of signal-to-noise ratio (SNR) in a wide coverage area including the shadow area (digital TV blind spot area), it is possible to provide high-quality digital TV service anytime and anywhere.

However, considering the commercially available 8-level residual sideband digital TV receiver chip and currently developed equalizer's ghost rejection range and dynamic ghost magnitude estimation range, a satisfactory reception signal-to-noise ratio (SNR) within a single frequency network service area is always achieved. ) And performance is not guaranteed.

As a solution to this problem, after estimating the information of each transmitter (transmitter ID (TxID), transmitter power (transmitter power), channel impulse response between the transmitter and receiver) from the signal received in the service area, There is a method of adjusting the transmission time-offset and the size of the transmitter.

For example, a method of estimating information of a transmitter from a signal received in a single frequency network service area is an RF watermark (Hidden-sequence) technique (A / 110). RF watermarks (RF-Watermarks) is a low-power two-level Pseudo-Random Sequence (SBR) is added to the existing A / 53 8-level residual sideband signal according to the watermark Bury Ratio (WBR).

In this case, to estimate the transmitter information from the received signal, the transmitter information is estimated by using the correlation power obtained by taking a correlation between the transmitter-specific identification code stored in the receiver and the received signal and the unique identification code used. do.

However, since RF-watermarks estimate the transmitter information by using correlation of identification codes, degradation of detection performance may occur due to relatively large in-band 8 level signal. have. In addition, there is a disadvantage in that a large amount of two-level identification codes must be received and processed in order to obtain accurate transmitter information required. Therefore, a transmitter information detection technique is required for efficient transmitter information estimation in a short time.

1 is a block diagram of an embodiment of a conventional 8-level residual sideband type digital TV transmitter.

As shown in FIG. 1, the conventional 8-level residual sideband type digital TV transmitter has a channel encoder 101, a multiplexer 102, a pilot inserter 103, an 8-VSB modulator 104, and a frequency. Up-converter 105 and the like.

Its operation shows that in the eight-level residual sideband transmission system, the signal spectrum is symmetrical, so that 5.38 MHz and roll-off factor (half of the 10.76 MHz band for 10.76 Msps (symbol per second) data transmission are used. By adding the bands added by the roll-off factor, a signal is transmitted through a conventional analog broadcasting band of 6 MHz in total. The signal modulated in the 8-level residual sideband scheme is propagated to the air using a radio frequency (RF) band. Here, since the function and operation of each component is already known standard technology, it will not be described in detail any more.

2 is a block diagram of an embodiment of a conventional 8-level residual sideband type digital TV receiver.

As shown in FIG. 2, a conventional 8-level residual sideband type receiver includes a tuner 201, a SAW filter and a carrier recovery unit 202, a symbol clock recovery unit 203, an 8-VSB demodulator 204, A pilot remover 205, a channel equalizer 206, a channel decoder 207, and the like.

In operation, when the 8-VSB signal of the radio frequency band is received through the antenna, the tuner 201 selects a desired channel frequency using a heterodyne demodulation method and then the VSB signal of the radio frequency band loaded on the channel frequency. Is shifted to a fixed intermediate frequency (IF) band, and the SAW filter 202 appropriately removes signals outside the signal band. The signal of the intermediate frequency band is found by the carrier recovery unit 202, and is sampled by an analog / digital converter using a clock recovered by the symbol clock recovery unit 203 and converted into a digital signal. The digitized 8-VSB signal passes through the 8-VSB demodulator 204 and the pilot signal is removed through the pilot remover 205, and then passes through the channel equalizer 206, the channel decoder 207, and the like. Decrypted. Here, since the function and operation of each component is already known standard technology, it will not be described in detail any more.

FIG. 3 is a diagram illustrating an embodiment of an 8-level residual sideband type digital TV transmitter using a conventional RF watermark technique.

As shown in FIG. 3, the digital TV transmitter is a low power two-level pseudo-random sequence according to a watermark bury ratio (WBR) so that the transmitter information can be estimated from a signal received at the digital TV receiver. The structure of generating and transmitting to the existing A / 53 8-level residual sideband signal is shown. To this end, as illustrated in FIG. 3, an RF watermark identifier generator 302 and a summer 303 block are further added to the structure of FIG. 1.

4 is a diagram illustrating an embodiment of an 8-level residual sideband scheme digital TV receiver using a conventional RF watermark technique.

As shown in FIG. 4, the digital TV receiver compares FIG. 2 with an identification code that takes a correlation between a transmitter-specific identification code and a reception signal previously stored in the receiver to estimate transmitter information from the received signal. It further includes a detector 401.

A process of detecting transmitter information will be described below with reference to FIGS. 1 to 4.

이라 하고, 식별 부호 삽입 전의 8 레벨 잔류측파대 디지털 TV 신호를

이라 하며, 식별 부호 삽입 후의 디지털 TV 신호를

이라 할 때 i번째 송신기로부터 전송되는 신호는 하기의 [수학식 1]과 같다.Low-power two-level pseudo-random sequence generated according to watermark bury ratio (WBR)

And the 8-level residual sideband digital TV signal before the identification code insertion.

Called digital TV signal

In this case, the signal transmitted from the i th transmitter is represented by Equation 1 below.

는 대역확산 신호의 삽입레벨을 조절하는 WBR 상수값이다.here,

Is a WBR constant that adjusts the insertion level of the spread signal.

를 통과하여 디지털 TV 수신기로 수신되었을 경우, 수신신호

는 하기의 [수학식 2]와 같이 정리될 수 있다.The signal of Equation 1 is a channel

Received signal when received through digital TV receiver

Can be summarized as in Equation 2 below.

은 전송과정 중에 i번째 송신기 신호에 삽입된 잡음신호를 나타낸다

. 단일 주파수 망 내부에 위치한 송신기의 총 개수를 M이라 할 때 디지털 TV 수신기로 입력된 전체 신호는 하기의 [수학식 3]과 같다.here,

Denotes the noise signal inserted in the i th transmitter signal during the transmission process.

. When the total number of transmitters located inside a single frequency network is M, the entire signal input to the digital TV receiver is expressed by Equation 3 below.

과 j번째 송신기의 RF 워터마크(RF-Watermarks) 신호

간의 상호 상관관계 함수는 하기의 [수학식 4]와 같이 계산된다.The digital TV receiver extracts the received signal and the RF watermark (RF-) to extract transmitter identification information such as the presence, location information, and signal strength of each transmitter from the digital TV received signal into which the RF watermarks signal is inserted. Watermarks) The cross-correlation property between signals is used. That is, the received total signal

RF-Watermarks Signals from the and jth Transmitters

The cross-correlation function between is calculated as shown in Equation 4 below.

는 단위응답 함수로 추정할 수 있다. 또한 상기 [수학식 4]에서 두 번째 항과 세 번째 항은 동일 송신기 혹은 다른 송신기의 대역내 디지털 TV 신호 성분에 의해 발생되는 일종의 잡음성분을 나타낸다. 따라서 채널응답 함수

를 통과한 j번째 송신신호에 대한 송신기 식별 정보는

로 추정된다. 이 경우에 신호 대 잡음비(SNR)는 하기의 [수학식 5]와 같으며, 이 값이 클수록 송신기 식별 성능이 우수해진다.Here, using the orthogonality of the selected spread spectrum signal, the first term of Equation 4

Can be estimated as a unit response function. In addition, the second term and the third term in Equation 4 indicate a kind of noise component generated by in-band digital TV signal components of the same transmitter or another transmitter. Channel response function

Transmitter identification information for the jth transmission signal passing through

Is estimated. In this case, the signal-to-noise ratio (SNR) is expressed by Equation 5 below, and the larger this value, the better the transmitter identification performance.

. 따라서 수신된 신호에 직접적으로 상관관계를 적용할 경우, 상기 [수학식 5]의 분자 성분, 즉 잡음 성분 전력의 대부분을 차지하는 대역내 디지털 TV 신호인

으로 인해 송신기 식별을 위한 전체적인 신호 대 잡음비(SNR)가 낮아지게 된다.As described above, the transmitter information detection process is performed using the correlation between the received signal and the identification code. However, since the identification code inserted at a constant level in the existing digital TV signal is determined to minimize the impact of the transmission signal power loss and the reception signal, the power size of the identification code is very small compared to the in-band digital TV signal components.

. Therefore, when the correlation is directly applied to the received signal, the in-band digital TV signal that occupies most of the power of the molecular component, that is, the noise component of Equation 5,

This lowers the overall signal-to-noise ratio (SNR) for transmitter identification.

The present invention has been proposed in order to solve the above problems, and after removing the pure digital TV signal from the total digital TV signal received by the digital TV receiver to detect the identification code signal for detecting the identification information for identifying each transmitter It is an object of the present invention to provide an identification code detecting apparatus and a method thereof.

In other words, the present invention, when configuring a single frequency network consisting of multiple transmitters, identification information for identifying each transmitter after minimizing in-band digital TV signal interference which has the greatest influence on transmitter identification using channel equalizer output stage information. An object of the present invention is to provide an apparatus for detecting an identification code and a method thereof.

That is, according to the present invention, when a digital TV receiver detects identification information such as position information and signal strength of a transmitter by using correlation of a unique identification code of a transmitter located within a single frequency network, an output signal of a channel equalizer is detected. By recovering only 8 levels of digital TV signal from the channel equalizer output signal and removing it from the channel equalizer output signal, the transmitter identification code is detected by using the correlation with the transmitter identification code, so that the identification code detection apparatus is simply It is an object of the present invention to provide an apparatus and a method for detecting an identification code, which can greatly improve the signal-to-noise ratio (SNR) by using a position setting (change).

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

An apparatus of the present invention for achieving the above object, in the identification code detection device for transmitter identification, a channel equalizer for compensating the channel by performing a channel equalization process for the output signal from the pilot canceling unit of the digital TV receiver ; A data symbol detector for detecting (restoring) only 8 levels of in-band digital TV signals from the signal that has been channel-equalized in the channel equalizer; A subtractor for removing only an in-band digital TV signal output from the data symbol detector from a signal obtained by performing channel equalization in the channel equalizer; And an identification code detector for detecting transmitter identification information by using a correlation between an output signal of the subtractor and a transmitter unique identification code stored in advance.

In the method of the present invention, there is provided a method for detecting an identification code for transmitter identification, comprising: performing a channel equalization process on a digital TV signal from which a pilot has been removed; Detecting (restoring) only 8 levels of in-band digital TV signals from the signal having the channel equalization; Removing the detected in-band digital TV signal from the signal having the channel equalization; And detecting transmitter identification information by using a correlation between a signal from which the in-band digital TV signal is removed and a transmitter unique identification code previously stored.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a block diagram of an embodiment of a digital TV receiver including an apparatus for detecting an identification code for transmitter identification according to the present invention.

As shown in FIG. 5, when an 8-VSB signal of a radio frequency band is received through an antenna, the tuner 201, the SAW filter and the carrier recovery unit 202, the symbol clock recovery (203), 8 After passing through the VSB demodulator 204, the pilot removing unit 205, and the like, it is input to the identification code detecting device 501 for detecting the transmitter identification code. Then, the identification code detection device 501 detects the transmitter information by using the correlation between the transmitter identification information and the received signal located in the single frequency network.

6 is a detailed configuration diagram of an apparatus for detecting an identification code for identifying a transmitter according to the present invention.

As shown in FIG. 6, the identification code detecting apparatus 501 for transmitter identification according to the present invention performs a channel equalization process on an output signal from the pilot removing unit 205 of the digital TV receiver. The DTV data detector 601 detects (restores) only 8 levels of in-band digital TV signals from the channel equalized signal, and the in-band digital TV signals detected by the DTV data detector 601 to perform channel equalization. For detecting transmitter identification information by using a correlation between the DTV data remover 603 for removing from the performed signal and the transmitter unique identifier stored in the receiver and the output signal of the DTV data remover 603 An identification code detector 401 is included.

The DTV data detector 601 performs a channel equalization process on the output signal from the pilot remover 205 of the digital TV receiver to compensate for the channel, and the channel equalizer 206. A data symbol detector 602 for detecting (restoring) only 8 levels of in-band digital TV signals from the signal having channel equalization.

The DTV data remover 603 includes a subtractor 604 for removing only the in-band digital TV signal output from the data symbol detector 602 from the channel equalization signal performed by the channel equalizer 206. do.

Next, the identification code detection method for transmitter identification will be described in detail with reference to FIGS. 5 and 6 as follows.

을 송출하고, 각 송출 신호는 개별적인 채널

를 통과한 후 합쳐져서 디지털 TV 수신기로 입력된다. 이 경우에 디지털 TV 수신기로 입력되는 전체 신호는 하기의 [수학식 6]과 같다.Each digital TV transmitter in a single frequency network has the same data with each identification code inserted at the same time.

Each signal is a separate channel

After passing through, they are combined and input to the digital TV receiver. In this case, the entire signal input to the digital TV receiver is expressed by Equation 6 below.

은 개별적인 채널

들의 합인 통합 채널을 의미한다.In Equation 6 above

Is an individual channel

It means the integrated channel that is the sum of these.

를 갖는 채널 등화기(206)를 거치면 하기의 [수학식 7]과 같이 표현된다.Once the signal received by the digital TV receiver is an impulse response

After passing through the channel equalizer 206 having the following equation (7).

에 대한 푸리에 변환(Fourier Transform)은

이라 표현할 수 있고,

에 대한 푸리에 변환은

라 표현할 수 있다. 만일, 단일 주파수 망 구성에서 디지털 TV 수신기의 채널 등화기(206)가 각 디지털 TV 송신기로부터의 신호가 통과한 채널을 모두 보상한다고 가정하면, 상기 채널 등화기(206)의 임펄스 응답

는 하기의 [수학식 8]과 같이 표현 가능하며, 이 경우에 상기 [수학식 7]은 하기의 [수학식 9]와 같이 정리된다.In [Equation 7] above

Fourier Transform for

Can be expressed as

Fourier transform for

Can be expressed. If it is assumed that the channel equalizer 206 of the digital TV receiver compensates for all channels through which the signal from each digital TV transmitter passes in a single frequency network configuration, the impulse response of the channel equalizer 206 is assumed.

Can be expressed as Equation 8 below, in which case Equation 7 is summarized as Equation 9 below.

과 같이 정의하자. 그러면, DTV 데이터 제거기(603)에서는 상기 [수학식 9]의 채널 등화기(206)의 출력 신호로부터 DTV 데이터 검출부(601)의 출력 신호를 제거하게 되는데, 그 과정은 하기의 [수학식 10]과 같다.When the output signal of the channel equalizer 206 passes through the DTV data detector 601, it is restored (detected) to an eight-level digital TV signal.

Let's define Then, the DTV data remover 603 removes the output signal of the DTV data detector 601 from the output signal of the channel equalizer 206 of Equation 9, which is described in Equation 10 below. Same as

이다. 채널 등화기(206)에서 채널에 대한 보상이 끝났으므로

가 되고,

이 성립한다. 따라서 상기 [수학식 10]은 하기의 [수학식 11]과 같이 정리된다.here,

to be. Since the channel equalizer 206 has completed the compensation for the channel,

Become,

This holds true. Therefore, Equation 10 is summarized as in Equation 11 below.

과 j번째 송신기의 식별 부호

간의 상호 상관관계 함수를 계산하게 되고, 그 과정은 하기의 [수학식 12]와 같다.Finally, the identification code detector 401 receives the signal of [Equation 11] received

And identification symbols of the jth transmitter

The cross-correlation function between the two is calculated, and the process is expressed by Equation 12 below.

를 통과한 j번째 송신신호에 대한 송 신기 식별 정보는 상기 도 6에 도시된 식별부호 검출 장치(501)에 의해

로 새롭게 추정된다. 이 경우에 신호 대 잡음비(SNR)는 하기의 [수학식 13]과 같다.In Equation 12, the second term and the third term represent correlation noises generated by identification codes and white noise components of the same digital TV transmitter or another digital TV transmitter. Channel response function

Transmitter identification information for the j th transmission signal passed through the identification code detection apparatus 501 shown in FIG.

Is newly estimated. In this case, the signal-to-noise ratio (SNR) is expressed by Equation 13 below.

가 제거됨으로써, 전체적인 신호 대 잡음비(SNR)가 크게 향상된다.In-band digital TV signal, which occupies most of the noise component power, compared to Equation 5, which directly correlates the received signal.

By eliminating, the overall signal-to-noise ratio (SNR) is greatly improved.

FIG. 7 illustrates an example of an output waveform of an identification code detecting apparatus for identifying a transmitter in the presence of white noise, and is a result obtained by directly applying correlation to an existing received signal.

가 제거된 결과를 나타내고 있다.8 is an exemplary diagram of an output waveform of an identification code detecting apparatus for identifying a transmitter according to the present invention in the presence of white noise, and shows an in-band digital TV signal according to the present invention.

Shows the result of removal.

As shown in Figures 7 and 8, it can be seen that the results obtained by the present invention have a higher signal-to-noise ratio (SNR) than conventional methods.

As described above, in the case of applying the RF watermarking technique when constructing a single frequency network composed of multiple transmitters, an in-band digital TV signal having a power greater than that of a transmitter identification code is always present in the received signal. Since this acts as a large interference component in transmitter identification, the present invention minimizes in-band digital TV signal interference by using output information of the channel equalizer, thereby enabling accurate transmitter identification.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention as described above, when detecting the identification information such as the position information and signal strength of the transmitter using the correlation of the unique identification code of the transmitter located inside the single frequency network in the digital TV receiver, By recovering only the 8-level digital TV signal from the output signal and removing it from the channel equalizer output signal, the transmitter identification code is detected using correlation with the transmitter identification code, thereby simply detecting the identification code without changing the structure of the receiver. Using the device's positioning (change) has an excellent effect of significantly improving the signal-to-noise ratio (SNR).

Claims (4)

delete delete In the identification code detection device for transmitter identification, A channel equalizer for compensating for the channel by performing a channel equalization process on the output signal from the pilot remover of the digital TV receiver; A data symbol detector for detecting (restoring) only 8 levels of in-band digital TV signals from the signal that has been channel-equalized in the channel equalizer; A subtractor for removing only an in-band digital TV signal output from the data symbol detector from a signal obtained by performing channel equalization in the channel equalizer; And Identification code detector for detecting transmitter identification information by using the correlation between the output signal of the subtractor and the transmitter unique identification code stored in advance Identification code detection device for transmitter identification comprising a. In the identification code detection method for transmitter identification, Compensating for the channel by performing a channel equalization process on the pilot-free digital TV signal; Detecting (restoring) only 8 levels of in-band digital TV signals from the signal having the channel equalization; Removing the detected in-band digital TV signal from the signal having the channel equalization; And Detecting transmitter identification information using a correlation between a signal from which the in-band digital TV signal is removed and a transmitter unique identification code previously stored; Identification detection method for transmitter identification comprising a.

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