KR100968677B1 - Distributed Translator with Received Signal Synchronization, and Method thereof - Google Patents

Abstract

Provided are a distributed relay apparatus and a method of synchronizing a received signal. The distributed relay apparatus demodulates a received signal and extracts synchronization information from the received signal, a modulator for generating and modulating a transmission frame based on the extracted synchronization information, and the modulated transmission signal according to the transmission timing. It includes a transmitting unit for transmitting.

ATSC, Distributed Relay, VSB

Description

Distributed relay device synchronized with received signal and method thereof

The present invention relates to the same channel relay network in a digital TV broadcasting network. In particular, a distributed relay capable of synchronizing data by constructing a data frame using information extracted from a received signal and performing encoder memory initialization without a separate external control signal. An apparatus and a method thereof are provided.

In general, the relay device is installed in an area in which the signal of the main transmitter is weakly received to solve reception anxiety and to widen the transmission area of the main transmitter transmission signal.

1 shows a configuration of a general ATSC digital TV relay device.

Referring to FIG. 1, a general digital TV relay device includes a VSB (Vestigial Side Band) demodulator 101 for receiving and demodulating a transmission signal of a main transmitter (not shown), and a modulation stage for modulating and transmitting the demodulated signal again. (103).

The VSB demodulation stage 101 includes a tuner 105, an AD converter 107, and a VSB decoder 109.

The tuner 105 selects a desired channel by receiving the RF signal transmitted from the main transmitter.

The AD converter 107 converts an analog signal corresponding to the selected channel into a digital signal.

The VSB decoder 109 demodulates the digitally converted signal into a TS (Transport Stream) transmitted by a transmitter.

The modulation stage 103 includes a VSB modulator 111, an up converter 115, and a frequency synchronizer 113.

The reconstructed TS stream is input to the VSB modulator 111 to undergo a modulation process such as encoding and interleaving again.

The up-converter 115 up-converts a signal modulated by the frequency generated by the VSB modulator 111 to a desired channel.

2 shows a configuration of a repeater using a specific packet according to the prior art.

In the distributed relay system according to the prior art, a distributed transmitter packet is inserted into a transport stream of a performance studio to configure a distributed transmitter and a distributed relay using distributed packet information.

As shown in Fig. 2, the distributed relay system using distributed transmission packet information is

RF signal receiving antenna (3), band pass filter (BPF) 41, high output amplifier (HPA; 62), BPF (63), RF transmitting antenna (7), the RF receiving antenna (3) It simply amplifies the received RF signal and transmits it again.

The distributed relay system using the distributed transmission packet information amplifies the received RF signal through the HPA after removing the adjacent channel signal by the band pass filter. The signal amplified as described above includes channel noise included in the received signal. The adjacent channel signal generated by the HPA is removed by the channel filter, and the signal from which the adjacent channel signal is removed is transmitted.

Since the distributed relay system according to the related art has to insert a distributed transmission packet into a transport stream transmitted from a performance studio, a change in the relay apparatus and the broadcast transmission system shown in FIG. 1 is required.

3 shows a configuration of a distributed repeater for retransmitting a symbol in baseband.

Another distributed relay system according to the prior art is a system that demodulates a transmission signal of a main transmitter to a symbol level and converts it into an RF signal and relays it.

As shown in FIG. 3, the system for demodulating the transmission signal of the main transmitter to a symbol level and converting the signal to an RF signal and relaying the RF signal is performed on the RF receiving antenna 3, the BPF 41, the amplifier 42, and the intermediate frequency signal. It consists of a mixer 43 for converting (IF), a local oscillator 45, a BPF for IF 44, a mixer 61, an HPA 62, a BPF 63, an RF transmission antenna 7, The RF signal received from the RF receiving antenna is converted into IF, and then converted into RF and amplified and transmitted.

The distributed relay system according to the related art can remodulate using a signal transmitted from a main transmitter, but there is a disadvantage in that error correction of a received signal cannot be performed.

In conclusion, the distributed relay system according to the prior art has a problem that it is difficult to apply in a communication environment that requires a change or replacement for the transmission and performance facilities, or poor reception environment.

Accordingly, an aspect of the present invention is to provide a distributed relay apparatus and method capable of constructing a transmission data frame using information extracted from a received signal without a separate external control signal.

Another object of the present invention is to provide a distributed relay apparatus and method capable of synchronizing distributed relay data by initializing a memory of a trellis encoder using GPS information.

In addition, the present invention is to provide a distributed relay apparatus and method which can maintain the transmission timing by adjusting the transmission timing in consideration of the delay time for generating the transmission data frame from the received data frame.

In order to solve the above technical problem, an embodiment of the present invention includes a demodulator for demodulating a received signal and extracting synchronization information from a received signal, and a modulator for generating and modulating a transmission frame based on the extracted synchronization information. And a transmitter for transmitting the modulated transmission signal according to the transmission timing.

Further, another embodiment of the present invention extracts synchronization information from a frame structure of a received signal, constructs a transmission frame using the synchronization information, modulates the transmission frame, and transmits the modulated transmission frame. According to the present invention, there is provided a method of operating a distributed relay apparatus including transmitting.

Another embodiment of the present invention is to demodulate a received signal to extract a transport stream, reconstruct the transport stream into outgoing frames, and send out the outgoing frame in consideration of the delay time caused by the reconstruction time of the outgoing frame. It provides a method of operating a distributed relay device comprising a.

According to the present invention, unlike the conventional method of inserting specific data into a transmission packet of a performance station, distributed repeaters can be configured at the same frequency without any change in the transmission station and performance facility.

In addition, unlike the conventional method of recovering and retransmitting a symbol, the present invention performs data recovery by error correction inside a repeater. Therefore, when the present invention is applied, the same channel relay network can be easily configured even in a poor reception environment. Can be.

In addition, the present invention can obtain the frame synchronization of the received data and the transmitted data through some modification of the configuration of the receiving chip, thereby avoiding the complexity of the implementation and economically implementing the same channel repeater.

 BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In describing the present invention, if it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terminology used herein is a term used to properly express a preferred embodiment of the present invention, which may vary according to a user, an operator's intention, or a custom in the field to which the present invention belongs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.

In the following description, the distributed relay apparatus may be applied to distributed translations configured in the same channel in two or more repeaters, and the scope of the present invention is not limited thereto, and other relay apparatuses performing the same principle. Applicable to

The description of the main symbols used in the description and the drawings of the present invention are as follows.

ADC: Analog to Digital Conversion, Digital Conversion of Analog Signal

ATSC: Advanced Television Systems Committee, US Next Generation Broadcasting System Committee

Even / Odd field: Even field, odd field of ATSC data frame

Exciter: Modulation and RF Converter

Frame Sync Detector: Frame Sync Detector of ATSC Data Frame

Frame Sync Processor: Frame Sync Processor

Frequency Synthesizer: Frequency Synthesizer

GPS: Global Positioning System

IF: Intermediate Frequency, Intermediate Frequency Signal

Modulator: Modulator

PPS: Pulse per second. Pulses per second

Pulse Generator: GPS Reference Pulse Generator

RF: Radio Frequency, Radio Wave Signal

Sync: synchronization

Timing Processor: Transmission Timing Processor

10 MHz: GPS reference clock

Transport Stream (TS): MPEG 2 Transport Stream

Trellis coder: Trellis coder

Tuner: RF Frequency Selector

TxID Inserter: Transmitter Identification Inserter

Up Converter: Frequency Upconverter

VSB: Vestigial Side Band

The basic principle of the present invention is to demodulate a received signal into a transport stream, obtain frame synchronization information from the frame structure of the received signal, reconstruct the transport stream into an outgoing frame, and delay time by the reconstruction time of the outgoing frame. In this regard, the timing of the transmission of the transmission frame is adjusted.

The basic principle of the present invention is to initialize the state memory for lattice coding the transmission signal periodically or aperiodically in accordance with the reference signal, thereby matching the data transmitted in the distributed relay period.

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

4 shows a configuration of a distributed relay apparatus according to an embodiment of the present invention.

Referring to FIG. 4, the distributed relay device includes a tuner unit 401, an AD converter 403, a VSB demodulator 405, a VSB modulator 407, and an up converter. 408, a frequency synthesizer 409, a GPS processor 411, and a remote controller 413.

The tuner 401 and the AD converter 403 perform the same functions as the tuner 105 and the AD converter 107 shown in FIG.

Accordingly, the tuner unit 401 receives an RF signal corresponding to the selected channel and converts it into an IF or baseband signal.

In addition, the AD converter 403 converts the analog output signal of the tuner 401 into a digital signal.

The VSB modulator 407, the up-converter 408, and the frequency synthesizer 409 correspond to the VSB Exciter of a general distributed relay device.

The VSB demodulator 405 demodulates the received signal to extract an MPEG TS (Transport Stream), and extracts frame synchronization information from the frame structure of the received signal.

In this case, the synchronization information may further include field synchronization information for the prefield / rightfield of the ATSC frame.

In addition, the VSB demodulator 405 may include an equalizer for channel equalization and an FEC decoder.

As shown in FIG. 4, the extracted frame synchronization information is provided to a VSB modulator of a VSB Exciter.

The VSB modulator 407 generates a transmission frame of the demodulated TS based on the extracted synchronization information and VSB modulates it.

The up-converter 408 performs the same function as the up-converter 115 shown in FIG. 1.

The frequency synthesizer 409 determines a transmission output frequency by receiving a reference frequency, similarly to the frequency synchronizer 113 shown in FIG. 1.

The GPS processor 411 receives a GPS signal to generate a reference frequency (10 MHz) and a pulse signal (1 Hz), and provide the same to the frequency synthesizer 409 and the VSB modulator 407.

The remote controller 413 receives an external control signal and provides the received external control signal as a reference signal for initializing the state memory of the encoder.

In addition, the remote controller 413 may receive a signal for remote control of the entire distributed relay device and perform control according to the received remote control signal.

That is, according to an embodiment of the present invention, the state memory for grid coding may be initialized by frame synchronization information, a reference signal using a pulse signal generated by the GPS processor 411, and a reference signal input from the outside.

5 schematically illustrates a configuration of a VSB demodulator according to an embodiment of the present invention.

Referring to FIG. 5, the VSB demodulator includes a frame extractor 501, an error corrector 503, a TS extractor 505, and a frame sync information extractor 507.

The frame extractor 501 extracts frame information of the received signal.

The error correction unit 503 corrects an error of the received signal.

The TS extractor 505 decodes the received signal error corrected by the error corrector 503 and extracts a transport stream TS.

The frame extracting unit 501, the error correcting unit 503, and the TS extracting unit 505 constitute a VSB decoder.

The VSB demodulator may include an equalizer, a trellis decoder, a data de-interleaver, an RS decoder, a de-randomizer, and the like. In this case, error correction is performed through the RS decoder. In the prior art, since the method of retransmitting the symbol signal does not go through the RS decoder, the present invention has an excellent threshold point C / N by about 3 dB compared to the prior art.

The frame synchronization information extractor 507 extracts the frame synchronization information of the EVEN / ODD field from the frame structure of the received signal extracted by the frame extractor 501 and provides it to the VSB modulator 407.

6 schematically illustrates a configuration of a VSB modulator according to an embodiment of the present invention.

Referring to FIG. 6, the VSB modulator includes a data randomizer 601, an RS encoder 603, a data interleaver 605, a trellis (trellis) encoder 607, a transmission frame configuration unit 609, and a VSB modulation / And an RF conversion 617 and a memory initialization control unit 611.

The data randomizer 601, the RS encoder 603, and the data interleaver 605 are provided in general VSB modulation means, and a detailed description thereof will be omitted.

The trellis encoder 607 trellis-codes the transport stream.

The memory initialization controller 611 performs a function of periodically or aperiodically initializing a state memory (not shown) included in the grid encoder 607.

That is, the memory initialization control unit 611 periodically initializes the state memory based on the frame synchronization information.

In addition, the memory initialization controller 611 may generate a reference signal to initialize the state memory at a specific time period based on the pulse signal 613 provided from the GPS processor 411.

In addition, the reference signal may be a remote control signal 615 input from the remote control unit 413.

Therefore, the memory initialization control unit 611 controls the state memory (three) of the trellis encoder of the ATSC standard to be initialized by a reference signal for initialization (reset) of the state memory.

The transmission frame configuration unit 609 receives and stores the frame synchronization information of the Even / ODD field extracted from the frame structure of the received signal.

The frame synchronization information is provided to the memory initialization control unit 611 and used as a signal for initializing a state memory, and used as synchronization information for configuring an outgoing frame.

The transmission frame configuration unit 609 adds a field synchronization signal for every 313 frames of the TS signal having a 188-byte structure.

The VSB modulation / RF conversion 617 performs signal processing such as pilot insertion, VSB filtering, and RF upconversion to perform VSB modulation on the transmitted frame.

7 shows an example of extracting frame synchronization information according to an embodiment of the present invention and a configuration of a transmission frame using the same.

Referring to FIG. 7, the frame synchronization information extractor 703 extracts a plurality of field sync signals from the temporal flow 701 of the received VSB data frame.

The extracted plurality of field synchronization signals are provided to the transmission frame generator 705.

The transmission frame generation unit 705 generates a VSB transmission frame 707 using the plurality of field synchronization signals.

Accordingly, the MPEG transport stream has a new transmission frame structure by the field sync signal.

8 shows a schematic configuration of a GPS processing unit according to an embodiment of the present invention.

Referring to FIG. 8, the GPS processor 411 may include a GPS signal receiver 801 for receiving a GPS signal, a GPS signal controller 803 for generating a frequency reference signal of 10 MHz from the received GPS signal, and the GPS signal. And a pulse signal generator 805 for generating a 1 Hz pulse signal.

The 10 MHz reference signal is used to determine the transmit output frequency as described above, and all frequencies used in the modulation process are synchronized with the 10 MHz reference signal.

With GPS, the same GPS 10MHz reference clock can be obtained at all transmitters, which can be used to obtain frequency synchronization. This is a common way to match the frequencies of the transmitters and repeaters that make up the SFN.

9 shows a schematic configuration of a transmission timing adjusting device according to an embodiment of the present invention.

The transmission timing adjusting device shown in FIG. 9 may be a detailed configuration of the transmission frame configuration unit 609. In addition, the transmission timing adjusting device may be provided at the end of the VSB modulator to perform a function of adjusting the transmission timing.

Referring to FIG. 9, the apparatus for adjusting timing of transmission performs a FIFO function by receiving a frame synchronization controller 901 for outputting a frame synchronization control signal, a frame offset controller 903 for adjusting frame offset according to the control signal, and symbol data. A FIFO memory 905.

The apparatus for adjusting timing of transmission further includes means for controlling transmission (Tx) timing offset in accordance with the ATSC standard (not shown) and a Tx ID inserter 907 for inserting a relay device identifier (Tx ID) according to the ATSC standard. Can be done.

Frame offset adjustment principle according to an embodiment of the present invention is as shown in FIG.

Referring to FIG. 10, t _D represents a time taken to extract a TS from a received input frame 1001 to generate an output frame (output frame) 1003. That is, t _D represents the difference between the starting point of the output frame and the starting point of the input frame.

In addition, t _max represents the maximum delay that can occur in the chipset installed for each repeater.

Accordingly, in order to fix the transmission timing to the maximum delay time t _max , the frame offset control unit 703 delays the maximum delay time by t _C minus t _D so that the final output frame 1005 is generated. To control.

Therefore, according to the embodiment of the present invention, the final output frame of the distributed relay device always secures a delay time of t _max .

11 illustrates a method of operating a distributed relay device according to an embodiment of the present invention.

Referring to FIG. 11, in the method of operating a distributed relay apparatus, the method may include extracting synchronization information from a frame structure of a received signal (S1101), constructing a transmission frame using the synchronization information (S1103), and Adjusting the offset (S1105), and transmitting the transmission frame in accordance with the transmission timing (S1107).

In step S1105, the offset of the transmission frame is determined in consideration of the frame offset obtained by subtracting the transmission frame generation time from the maximum delay time of the distributed relay device.

The step (S1107) of transmitting the transmission frame includes encoding the transmission frame according to the state information initialized according to the synchronization information, and modulating the encoded transmission frame with the residual sideband modulation.

12 illustrates a method of operating a distributed relay device according to another embodiment of the present invention.

Referring to FIG. 12, in the method of operating a distributed relay apparatus, demodulating a received signal into a transport stream to extract a TS (S1201), reconstructing the transport stream into an outgoing frame (S1203), and Adjusting the offset of the transmission frame in consideration of the reconstruction time (S1205) and transmitting the transmission frame according to the transmission timing (S1207).

In the step S1203 of reconstructing the transport stream into an outgoing frame, the outgoing frame may be configured by using frame synchronization information of the received signal.

Distributed relay device and method according to an embodiment of the present invention described above,

-In order to keep the received signal and the transmitted signal the same, the GPS reference frequency is used to generate the frequency of the transmitted signal.

In addition, the concept of receiving and sending frame synchronization and reset of trellis encoder state memory is introduced to match the data of the received signal and the transmitted signal.

In addition, a frame offset may be adjusted by introducing a FIFO buffer to adjust timing of a transmission signal.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

1 shows a configuration of a general ATSC digital TV relay device.

2 shows a configuration of a repeater using a specific packet according to the prior art.

3 shows a configuration of a distributed repeater for retransmitting a symbol in baseband.

4 shows a configuration of a distributed repeater for retransmitting a symbol in baseband.

5 schematically illustrates a configuration of a VSB demodulator according to an embodiment of the present invention.

6 schematically illustrates a configuration of a VSB modulator according to an embodiment of the present invention.

7 shows an example of extracting frame synchronization information according to an embodiment of the present invention and a configuration of a transmission frame using the same.

8 shows a schematic configuration of a GPS processing unit according to an embodiment of the present invention.

9 shows a schematic configuration of a transmission timing adjusting device according to an embodiment of the present invention.

10 is a view for explaining the principle of frame offset adjustment according to an embodiment of the present invention.

11 illustrates a method of operating a distributed relay device according to an embodiment of the present invention.

12 illustrates a method of operating a distributed relay device according to another embodiment of the present invention.

Claims (12)

A demodulator for demodulating a received signal to extract a transport stream and frame synchronization information from the received signal; A modulator for constructing a transmission data frame based on the extracted frame synchronization information and modulating the transmission data frame; And A transmission unit configured to transmit the modulated transmission data frame according to transmission timing, Wherein the modulator encodes the transport stream according to state information initialized according to the frame sync information, and generates a transmission data frame of the encoded transport stream according to the frame sync information. Distributed relay device. The method of claim 1, wherein the demodulation unit, An error correction unit correcting an error of the received signal; A transport stream extracting unit configured to extract the transport stream by decoding the error corrected received signal; And  And a synchronization information detector for extracting field synchronization information from the data frame structure of the decoded received signal. The method of claim 1, wherein the modulator, A trellis encoder for trellis encoding the extracted transport stream; An outgoing frame generator for generating outgoing data frames of the encoded transport stream based on the frame sync information; And And a memory initializer configured to initialize the memory of the grid encoder according to a reference signal. The method of claim 3, wherein And the frame synchronization information is field synchronization information extracted from a data frame structure of a received signal. The method of claim 3, wherein And the reference signal is generated by field synchronization information extracted from a frame structure of a received signal. The method of claim 3, wherein And the reference signal is a signal generated using a GPS pulse signal or an aperiodic signal input from the outside. The method of claim 1, wherein the delivery timing, And a frame offset obtained by subtracting a time for generating the transmission data frame from the maximum delay time of the distributed relay device. Extracting a transport stream and frame synchronization information from a data frame structure of a received signal; Construct a transmission data frame using the frame synchronization information; Modulate the outgoing data frame; And Transmitting the modulated transmission data frame according to transmission timing, The process of configuring the transmission data frame, Encoding the transport stream according to the state information initialized according to the frame sync information, and constructing a transmission data frame of the encoded transport stream according to the frame sync information. Method of operation of a distributed relay device. delete The method of claim 8, wherein the transmission timing, And a frame offset obtained by subtracting a time for generating the transmitted data frame from the maximum delay time of the distributed relay device. delete delete

Images