KR102461179B1 - Transmitting apparatus and receiving apparatus and control method thereof - Google Patents

Abstract

A transmitting device is disclosed. A transmitting apparatus for transmitting a signal in a layered division multiplexing (LDM) scheme includes a signal processing unit that overlaps first and second signals to generate an overlapped coded signal, and a transmission unit that multiplies the overlapped coded signal by a preset orthogonal code component and transmits it includes

Description

Transmitting device, receiving device and its control method { TRANSMITTING APPARATUS AND RECEIVING APPARATUS AND CONTROL METHOD THEREOF }

The present invention relates to a transmitting apparatus, a receiving apparatus, and a control method thereof, and more particularly, to a transmitting apparatus, a receiving apparatus, and a control method for transmitting a signal in an LDM manner.

In the information society of the 21st century, broadcasting and communication services are entering the era of full-scale digitalization, multi-channel, broadband, and high-quality. In particular, as the distribution of high-definition digital TVs, PMPs, and portable broadcasting devices has recently expanded, the demand for digital broadcasting services to support various reception methods is increasing.

In accordance with these demands, the standards group has established various standards and is providing various services that can satisfy the needs of users. Therefore, it is required to find a way to provide better services through better performance.

The present invention has been devised in response to the above needs, and an object of the present invention is to provide a transmitting apparatus, a receiving apparatus, and a control method thereof for processing and transmitting a signal in an LDM manner so that only a desired broadcast signal can be extracted from the receiving apparatus .

In order to achieve the above object, a transmitting apparatus for transmitting a signal in a layered division multiplexing (LDM) method according to an embodiment of the present invention for achieving the above object is a signal processing unit for generating an overlapping coding signal by overlapping first and second signals. and a transmitter for multiplying the superposition coded signal by a preset orthogonal code component and transmitting the multiplied signal.

Here, the orthogonal code component may be determined by a preset orthogonal code pattern.

Also, the signal processing unit may generate the overlapped coding signal by assigning different powers to the first and second signals and superimposing them in a layered division multiplexing (LDM) method.

Also, the first and second signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively.

In addition, the receiving apparatus for receiving the first and second superimposed coding signals transmitted from the first and second transmitting apparatuses according to an embodiment of the present invention, the first and second from the first transmitting apparatus and the second transmitting apparatus A receiver for receiving a signal during a second time interval, and first and second superimposed coded signals received from first and second transmitting apparatuses by multiplying a predetermined orthogonal code component by a signal received during the first and second time intervals and a signal processing unit for separating the .

Here, the orthogonal code component is a component known between the receiving apparatus and the first and second transmitting apparatuses, and is an orthogonal transmitted by multiplying the first and second superimposed coded signals by the first and second transmitting apparatuses. It can be an inverse component of a code component.

In addition, the signal processing unit may include a demapper that demodulates the separated first overlapped coded signal, a deinterleaver that deinterleaves an output of the demapper, and a decoder that decodes the output of the deinterleaver. .

Here, the first overlapping signal is a signal superimposed in an LDM method by allocating different powers to the first and second signals, and the second overlapping signal is obtained by allocating different powers to the third and fourth signals. It may be a signal overlapped by the LDM method.

In addition, the first and second signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively, and the third and fourth signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively.

On the other hand, the control method of the transmitting apparatus for transmitting a signal in the LDM (Layered Division Multiplexing) method according to an embodiment of the present invention, the step of overlap-coding the first and second signals to generate a superposition coded signal, and the overlapping and transmitting the coded signal by multiplying the predetermined orthogonal code component.

In addition, the generating of the overlapping coding signal may include generating the overlapping coding signal by assigning different powers to the first and second signals to overlap the first and second signals in a layered division multiplexing (LDM) method.

Here, the first and second signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively.

In addition, according to an embodiment of the present invention, there is provided a method for controlling a receiving device for receiving the first and second superimposed coding signals transmitted from the first and second transmitting devices, from the first transmitting device and the second transmitting device. Receiving a signal during first and second time intervals, and multiplying a signal received during the first and second time intervals by a preset orthogonal code component to first and second received from the first and second transmitting apparatuses Separating the overlapping coding signal.

Here, the orthogonal code component is a component known between the receiving apparatus and the first and second transmitting apparatuses, and is an orthogonal transmitted by multiplying the first and second superimposed coded signals by the first and second transmitting apparatuses. It may be an inverse component of the code component.

The method may further include performing demodulation on the separated first overlapping coding signal, performing the demodulated deinterleaving, and decoding the deinterleaved signal.

Here, the first overlapping signal is a signal superimposed in an LDM method by allocating different powers to the first and second signals, and the second overlapping signal is obtained by allocating different powers to the third and fourth signals. It may be a signal overlapped by the LDM method.

In addition, the first and second signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively, and the third and fourth signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively.

On the other hand, in a system including first and second transmitting apparatuses and a receiving apparatus for transmitting a signal in a layered division multiplexing (LDM) scheme according to an embodiment of the present invention, the first and second signals are overlapped by coding the first A first transmission device for generating a superposition coded signal and multiplying the superposed coding signal by a preset orthogonal code component to transmit, superposition coding the third and fourth signals to generate a second superposed coded signal, and to the superposed coded signal a second transmitting device for multiplying and transmitting an orthogonal code component, and a signal received during first and second time intervals from the first transmitting device and the second transmitting device, and during the first and second time intervals and a receiving apparatus for signal processing by separating the first and second superimposed coded signals from a received signal by multiplying by a predetermined orthogonal code component.

According to the above-described various embodiments, the reception device can extract only a desired broadcast signal without information on the counterpart channel.

1A to 1C are diagrams for explaining a frequency sharing type broadcasting technology discussed in NGH-W.
2 is a diagram illustrating a signal magnitude ratio according to a signal overlapping degree.
3 is a diagram illustrating a Shannon-limit according to a modulation scheme.
4 is a diagram for explaining a hierarchical spectrum of a frequency sharing type broadcasting system.
5 is a diagram illustrating an embodiment of a cloud transmission receiver using a hierarchical spectrum reuse scheme.
6 is a diagram for explaining the coverage of a frequency sharing type transmission having three streams.
7 is a diagram for explaining coverage of a frequency sharing type broadcast transmission network with respect to an existing SFN network having two streams.
8 is a diagram for explaining a difference between a conventional single frequency network (SFN) and a frequency sharing type broadcasting service when there are two transmitters.
9 is a diagram for explaining a service that appears when two transmitters transmit different programs in a frequency sharing type broadcasting system.
10 shows a frequency sharing type broadcast transmission model currently adopted in the ATSC 3.0 standard.
11 is a diagram showing the performance of the proposed system and the existing frequency sharing broadcasting system as a BER curve.
12 is a block diagram illustrating a configuration of a transmitting apparatus according to an embodiment of the present invention.
13 is a block diagram illustrating a configuration of a transmission apparatus according to another embodiment of the present invention.
14 and 15 are diagrams for explaining an overlapping coding signal according to an embodiment of the present invention.
16 is a block diagram illustrating a configuration of a receiving apparatus according to an embodiment of the present invention.
17 is a block diagram showing the configuration of a receiving apparatus according to another embodiment of the present invention.
18 is a flowchart illustrating a control method of a transmitting apparatus according to an embodiment of the present invention.
19 is a flowchart for explaining a method of controlling a transmitter according to an embodiment of the present invention.

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

1A to 1C are diagrams for explaining a frequency sharing type broadcasting technology discussed in NGH-W.

Even if a single frequency network is implemented, the problems for constructing a broadcasting network are still being discussed. In particular, the existing digital broadcasting service did not solve the problem of co-channel interference. For example, if a digital broadcasting system is assumed to be within about 100 km in diameter, co-channel interference (CCI) occurs within a single frequency, even though the reception is not reachable (after 100 km), and the potential interference affects up to 300 km. can give Therefore, in order to use other signals as the same channel within a single frequency, it must be installed at a distance of 400 km, and the frequency efficiency becomes very inefficient.

1A shows an ideal co-channel allocation environment in the area of the existing DTV system. As shown in FIG. 1A , it can be seen that the area not used by the same channel broadcasting service is very large, and the actual spatial utilization rate is only 28% compared to the entire area. Here, an area that is not actually usable (area without contrast) is called white space because it cannot actually be used at the same frequency. Accordingly, as shown in FIG. 1B , the white space region can overcome the space shortage efficiency through transmission of different frequencies, and when transmitting in this way, a plurality of frequencies must be used, so the frequency efficiency is very low. 1c shows a predictable scenario when a frequency sharing type broadcasting network is constructed. Compared to the existing single frequency network, the frequency sharing type broadcasting network has no correlation with the output of the position transmitter of the common channel transmitter in the corresponding broadcasting area, and the spatial utilization rate can be utilized at 100%.

As robustness against co-channel interference and the use of co-channel transmission are possible, it is expected that the frequency-sharing broadcast network can use more channels for broadcast services. In addition, since not all channels are used in urban areas, the increase in available channels helps to operate devices and systems that are not authorized by law, especially by utilizing various built-in equipment such as smartphones or tablet devices, repeaters, etc. Therefore, broadcasters can greatly utilize the interactive broadcasting service. Most of the existing digital broadcasting systems were developed 10-20 years ago, but the frequency sharing type broadcasting technology has recently developed considerably. Most digital broadcasting systems use MPEG-2 video coding, but recently H.264 and AVC standards have been proposed, showing a compression ratio of 50% or more for an HDTV service compared to the same data rate. In addition to the improvement of video coding, the development of a high-efficiency error correction coder close to the Shannon-limit such as the LDPC code, and the method of the diversity technology such as multiple antennas, the frequency sharing broadcasting technology is being developed.

A major issue related to a frequency-sharing broadcast transmission system is embodied in how to deal with co-channel interference. In particular, in the digital transmission wireless communication system, it is known that the co-channel indirect effect coincides with the white noise (Additive White Gaussian Noise: AWGN). Assume that it has an AWGN SNR threshold of up to . That is, when a broadcasting network of a shared frequency is constructed, a signal combined with noise having a negative SNR threshold, co-channel interference, and multi-path distortion power higher than the desired signal power can be configured. The frequency sharing broadcasting system divides co-channel interference into two types. First, when two or more uncorrelated receivers transmit signals, such as AWGN, or two or more transmitters in a single frequency environment The same program is transmitted, which is the same as the existing single-frequency network service scenario. The first case is described when the multipath delay spread is longer than the guard interval or equalizer range of the receiver, or when there is no equalizer implemented in the receiver. Also, when evaluating the reception performance, the worst case is 0dB echo with the same power level for the main path and multipath signal.

2 shows how a received signal is configured when two transmitters perform a broadcast service in a frequency sharing form.

α is calculated in dB and is calculated as a relative value. Therefore, assuming that the signals from transmitter 1 (Tx #1) and transmitter 2 (Tx #2) come in the same, that area is exposed to 0 dB echo and has the lowest performance degradation. If a frequency-sharing system has an AWGN threshold of -2dB to -3dB, it must be able to tolerate 0dB echo without an adaptive equalizer or guard interval. Multipath distortion in this situation must be dealt with by the error correction function of the system defined in the first co-channel interference type, and it must have an equalization or recovery system different from the existing single-frequency network.

Co-channel interference, which appears only in a frequency sharing broadcasting system, naturally causes multiple signals to overlap in the transmitter coverage area. The frequency sharing type broadcast transmission system has the advantage of being able to withstand the type of co-channel interference and being able to synchronize to a strong signal path. Therefore, as shown in FIG. 1C , the transmitter can be deployed without limitation in a designated service area and can transmit various programs. Unlike FIGS. 1A and 1B , a large area can be efficiently covered by using only a single frequency instead of four frequencies. It can be seen that the spectrum utilization is increased by a factor of 4 through this method. Since the overlapping coverage contour shown in FIG. 1C has a cloud-like shape, the name of the proposed new transmission system is called Cloud Transmission worldwide.

In the conventional single frequency, all transmitters transmit the same signal on the same RF channel. Since the signals from different transmitters have fixed frequencies and phases, the timing of signal transmission must be within the guard interval or range of the receiver's equalizer because the multi-delay spread is controlled in the cover area.

However, in cloud transmission, which is a frequency sharing broadcasting system, the same signal, different signals, and even combined signals can be transmitted from the transmitter of a single frequency broadcasting system. Different transmitters only require a fixed RF frequency and do not need to be fixed until the phase of the signal. Therefore, the transmission SNR of the frequency sharing type broadcasting network can be implemented with lower complexity and lower cost than the existing SNR. On the other hand, since it is necessary to control the transmission timing of the transmitter, the complexity of receiver calculation and the problem of fast receiver synchronization must be considered.

Two ways to improve spectral efficiency are to increase data throughput or data robustness, and most recent studies have focused on increasing data throughput and approaching the Shannon-limit. On the other hand, the frequency sharing type broadcast transmission system is concentrated in the negative SNR region of Shannon-limit. Although the data throughput of each RF channel is reduced, the reception robustness is greatly increased, while at the same time the spectral space reuse capability and the flexibility of the transmission tower location are greatly improved.

3 shows the Shannon-limit according to the modulation scheme of the system. It can be seen that the spectral efficiency becomes 0.4-0.5 bit/s/Hz when the SNR threshold is from -2 to -3 dB. Assuming that the bandwidth of the RF (Radio Frequency) channel is 6 MHz, the system processing data transmission rate is 2.4-3.0 Mbps. This level of low data rate makes it difficult to provide an actual HDTV service, but it is easy to provide one or more SDTV (Standard Definition Television) quality programs to portable mobiles, tablets, and indoor services.

A simple way to increase the data throughput of the system is to place two frequency-sharing base stations in the same location. For example, there is a method of transmitting two different broadcasting network signals to the same transmitter and antenna. This is possible because the characteristics of the frequency sharing system can strongly withstand co-channel interference. Co-locating the base stations will double the system data throughput, resulting in spectral efficiencies of 0.8-1.0 bits/s/Hz, and data rates of 6 MHz RF channels increasing by 5-6 Mps. Therefore, it is possible to provide HDTV service using HEVC in the proposed system. Another way to increase the data rate is to use the Hierarchical Spectrum Re-use method to significantly increase the data throughput because the cloud transmission system is very robust.

4 is a diagram for explaining a hierarchical spectrum reuse scheme.

The second digital broadcasting content B may be inserted into the existing stream through the method shown in FIG. 4 . For example, assuming that two broadcasting systems are transmitted, content A selects mobile broadcasting and low-transmission data covering a wide coverage, and content B selects fixed reception HDTV. In order to transmit two signals at the same time, content B is scaled to a low signal of about 5dB or less, and the two signals are added and transmitted.

5 is a diagram illustrating an embodiment of a cloud transmission receiver using a hierarchical spectrum reuse scheme.

Referring to the transmission structure of FIG. 4 and the receiver block diagram of FIG. 5, in the frequency sharing transmission signal system, the mobile broadcast content A first removes a transmission error through decoding, and then the decoded signal is fed back and separated from the received combined signal. and is used to decode crystal-fixed HD broadcast content. Assuming that content B is transmitted 5 dB below content A to successfully decode it, a signal with a minimum gain of about 10 dB for content A should also be included.

Assuming there are three data streams (or content) providing tiered services of different powers, with a data rate of 2.5-3.0 Mbps, stream A is the strongest signal, which can be used as a mobile and mobile service and provides quality SDTV programs. can provide In addition, the data rate of the combined stream of A and B can be increased to 9Mbps, and HDTV service can be provided using HEVC or SVC. It is expected that mobile reception of both streams A and B will be possible in the future with the development of channel estimation and signal interference cancellation technology. Since the combined stream (A+B+C) can provide a data throughput of 12 Mbps, the data in stream C can be used with 3D-TV or data services with fixed reception.

Assuming that the three streams (A+B+C) are implemented using the previously mentioned Spectrum Underlay technique, a spectral efficiency of about 2 bit/s/Hz is achieved within a channel of 6 MHz. This efficiency is smaller than the existing DTV system with a spectral efficiency of 3-5 bit/s/Hz. In order to improve this part, the frequency sharing type transmission system has the advantage of very efficient frequency utilization unlike the existing single frequency network.

Because a frequency-shared transport network can have more than one layer data service or more than one stream, stream A can transmit at low power over unused DTV channels, and stream B can be added later. to be. This means that when the existing digital TV service is not used, the power of frequency-sharing transmission can be developed to provide better coverage according to the service demand. In addition, the gradual implementation of a frequency-sharing transmission network can offer broadcasters more control over business plans and a transition to a new system. Accordingly, receiver arrangement tailored to the frequency sharing broadcasting system may be sequentially performed in a backward compatible manner. Previous receivers were designed to receive only stream A signals, but stream B can be used, so there is a demand for simultaneous reception of streams A and B. In the meantime, it is likely that the early-generation receivers designed only for stream A will gradually disappear. There will be different types of receivers, such as handsets and set-top boxes, to meet different market demands for different services, such as mobile, portable, and stationary devices. These receivers can decode all available data streams or some streams depending on the application.

FIG. 6 is a diagram illustrating coverage of a frequency sharing type transmission having three streams, and FIG. 7 is a diagram illustrating coverage of a frequency sharing type broadcast transmission network with respect to an existing SFN network having two streams.

Therefore, the frequency sharing type broadcasting can implement a service concept diagram in which three streams A, B, and C operate as shown in FIG. 6 . These services can be used for stream A fixed service, stream A+B also fixed service, stream A+B+C fixed service, and finally stream A mobile service.

8A and 8B are diagrams for explaining a difference between a conventional single frequency network (SFN) and a frequency sharing type broadcasting service when there are two transmitters.

In the existing single-frequency network, two transmitters transmit the same signal and overlap their coverage to transmit the same program, but in the case of frequency-sharing transmission, the two transmitters transmit different signals in streams A1 and A2, and each transmitter has different coverage for each program. to provide.

9 is a diagram for explaining a service that appears when two transmitters transmit different programs in a frequency sharing type broadcasting system.

As shown, assuming that each sender has two different streams, each stream is denoted as A1, B1 and A2, and B2 (A1, B1 and A2, B2 are different). It can be seen that the coverage of A1 and A2 is almost identical to that of FIG. 8 . Each transmitter has its own program coverage and there is an area where streams A1 and A2 can be simultaneously received. Since reception thresholds for streams B1 and B2 are not negative dB values, coverages for B1 and B2 do not overlap. However, when a directional reception antenna is used, an overlapping region for receiving both streams B1 and B2 is generated.

Meanwhile, according to an embodiment of the present invention, a method of simply transmitting a Signed Identity Matrix of +1 or -1 to the transmitter is taken. The component determination of +1 and -1 generally uses a well-known orthogonal code pattern, and when the form is received by the receiving end by time, it is transmitted so that it is completed. The difference from the existing frequency sharing broadcasting system is that data cannot be received in real time until an orthogonal code is formed.

For the convenience of the equation, the frequency sharing model of FIG. 8B is assumed and the vector r received at the k-th sample time and the j-th overlap time is expressed in Equation 1 below.

Here, H ₁ , H ₂ represents the Circulant Channel Matrix generated by Transmitter 1 and Transmitter 2, and is generally regarded as an equivalent model in which the Cyclic Prefix (CP) is removed in the OFDM system. It is assumed that the maximum multi-path tap is in the CP. Also, P _1j and P _2j are the Signed Identity Matrix to be transmitted by Transmitter 1 and Transmitter 2, and the form will be described later. Q denotes an FFT matrix, and d ₁ and d ₂ denote respective data vector streams transmitted from transmitter 1 and transmitter 2. Gaussian noise n is assumed to follow a Normal Distribution where the variance of the vector follows N and the mean is 0. Since it is an OFDM transmission model, the receiving end can take an FFT operation, and the equation can be expressed as follows.

Here, since it is assumed that the precoding matrices P1j and P2j are the Signed Identity Matrix, they will be in the form of multiplying only constants, and the above equation can be expressed as equivalent even if it is regarded as equivalent as follows.

Due to the OFDM channel characteristics, the circular channel constant value is converted to the frequency axis channel of the diagonal component, and the above equation can be written as follows.

The received signal received during two time slots can be expressed in a matrix form, and when j = 2, the equation is expressed as follows.

Since it is assumed that the proposed precoding transmission method transmits the Signed Identity Matrix, the above expression can be expressed the same as the expression simply multiplied by a constant value.

[1 1; 1 -1] to obtain a value multiplied by a constant.

The following reception model can be regarded as a method of transmitting using two antennas from one transmitter in a frequency sharing broadcasting system, or a model transmitting each data service from two transmitters. Since the proposed system can be immediately applied to models such as Figs. 6 and 8, a model of a frequency sharing transmission method currently adopted in the ATSC 3.0 standard is first considered.

10 is a frequency sharing type broadcast transmission model currently adopted in the ATSC 3.0 standard.

This technology discussed in CRC&ETRI requires a minimum SNR of -3dB or more to receive mobile service, and an SNR of 10dB or more is guaranteed for fixed broadcasting to be received. However, it is known that when four or more broadcast services are transmitted as shown in FIG. 9, only streams A1 and A2 should overlap, and if a signal enters a space where A1 and A2 overlap, streams B1 and B2 cannot be received. This is because -3dB, the minimum SNR condition of the most important mobile service, is not satisfied.

In the environment shown in FIG. 9 , the reception equivalent model can be rearranged as follows.

Assuming that the receiver knows that the transmitter is transmitted by multiplying the Signed Identity Matrix of +1 and -1, it preferentially multiplies the orthogonal matrix by the following without channel estimation.

Assuming that the receiver knows that the transmitter is multiplied by the Signed Identity Matrix of +1 and -1 to be transmitted, Z1 and Z2 can be divided into components independently.

The receiver can watch its own broadcast (or local broadcast) service without the need to cancel interference with the channel transmitted by the opposite transmitter.

이라 가정하면 본 특허는 3개 이상의 Tx 또는 수신 신호를 다 받지 않아도 간섭 제거를 완벽하게 할 수 있다.here

Assuming that , the present patent can completely eliminate interference even if three or more Tx or received signals are not received.

의 특징을 갖는다. 따라서 매트릭스의 랭크 특성을 이용하여 다음과 같은 상관관계를 갖는 r이 존재하게 된다. Proof) When M is an arbitrary size mxn matrix consisting of (1, -1, 0) and m>n,

has the characteristics of Therefore, using the rank characteristic of the matrix, r having the following correlation exists.

Meanwhile, in order to evaluate the performance of the proposed system, the system discussed in FIG. 8B was implemented. The FFT size and CP length were set to be the same for each service. The reason for performing the following is to perform synchronization or carrier recovery at the same time by implementing cost-effectively. However, modulation and encoding parameters were performed differently. High-level binary bits are mapped to QPSK after performing LDPC encoding. On the other hand, the lower-level binary bits were transmitted with 16QAM modulation. In this case, the data rate is implemented to transmit 2.4 and 10.4 Mbps, and SD programs, 720p HDTV, or UHDTV services can be transmitted in the 6MHz band using the HEVC codec. The parameters used in the simulation are shown in Table 1 below.

Layer Modulation Code Rate FFT Size Data Rate Upper QPSK 1/4 4K 2.4Mbps Lower 16-QAM 1/2 4K 10.4Mbps

The signal of the upper layer is regarded as the highest priority signal, so that the signal is restored first and the signal of the lower level is restored. The injection level between the two signals was set to be different by 5dB. The LDPC code used the DVB-T2 standard. Signal recovery was performed on the frequency axis.

11 is a diagram showing the performance of the proposed system and the existing frequency sharing broadcasting system as a BER curve.

As shown, the proposed system achieves the goal by showing a performance improvement of about 2dB for the lower layer and 6dB for the upper layer compared to the existing system because independent data extraction is possible without the need for interference cancellation technology.

12 is a block diagram illustrating a configuration of a transmitting apparatus according to an embodiment of the present invention.

12 , the transmitting apparatus 100 according to an embodiment of the present invention includes a signal processing unit 110 and a transmitting unit 120 .

The signal processing unit 110 generates a superposition coded signal by superimposing coding the first and second signals. In this case, the signal processing unit 110 may generate a superimposed coding signal by assigning different powers to the first and second signals and superimposing them in a layered division multiplexing (LDM) method. In this case, the first and second signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively.

The transmitter 120 multiplies the superposition coded signal by a preset orthogonal code component and transmits it. Here, the orthogonal code component may be determined by a preset orthogonal code pattern. A detailed method of multiplying the overlapping coding signal by multiplying a preset orthogonal code component and transmitting the signal has been described above based on the above equation, so a detailed description thereof will be omitted.

13 is a block diagram illustrating a configuration of a transmission apparatus according to another embodiment of the present invention.

Referring to FIG. 13 , the transmitting apparatus 200 includes a first signal processing unit 210 including a first encoder 211 , a first interleaver 212 , and a first mapper (or constellation mapper) 213 . Thus, after encoding and interleaving stream A, it may be mapped to a constellation point. In addition, the transmitting apparatus 100 includes a second signal processing unit 223 including a second encoder 221 , a second interleaver 222 and a second mapper 223 , and after encoding and interleaving the stream B This can be mapped to a constellation point.

In this case, the first and second encoders 211 and 221 are a Bose, Chaudhri, Hocquenghem (BCH) encoder (not shown), a Cyclic Redundancy Check (CRC) encoder (not shown) and a Low Density Parity Check (LDPC) encoder ( (not shown) may be performed by concatenating BCH encoding and LDPC encoding, or may be performed by concatenating CRC encoding and LDPC encoding.

In addition, the transmitting apparatus 200 adjusts the gain (ie, power) of the signal output from the second signal processing unit 220 through the base layer gain controller 230 , and then adjusts the gain (ie, power) to the first signal processing unit 210 . By overlapping the output signal, it is possible to generate a superimposed coding signal.

In addition, the transmitter 200 adjusts a gain for the overlapping coded signal through the gain controller 240 , interleaves constellation points to which the overlapping coded signal is mapped, ie, cells, through the time interleaver 250 , and then performs OFDM Through the transmitter 260 , the interleaved cells may be mapped to the OFDM frame and transmitted to the receivers 300 and 1000 . In this case, the OFDM transmitter 260 may transmit the overlapped coded signal by multiplying it by a preset orthogonal code component.

On the other hand, an example of a constellation for the overlapping coding signal may be shown as shown in FIG. 14 .

14, a signal corresponding to the upper layer is modulated with Quadrature Phase Shift Keying (QPSK) and a signal corresponding to the base layer is modulated with 64-QAM (Quadrature Amplitude Modulation) as an example.

Referring to FIG. 14 , it can be seen that the constellation points of the signal corresponding to the base layer having relatively small power are overlapped with respect to the constellation points of the signal corresponding to the upper layer having relatively large power.

On the other hand, when the overlapping coding signal is expressed in terms of power, it can be expressed as shown in FIG. 15 .

Referring to FIG. 15 , it can be seen that the power of the signal corresponding to the upper layer in the RF channel band is greater than the power of the signal corresponding to the base layer by about 5 dB.

16 is a block diagram illustrating a configuration of a receiving apparatus according to an embodiment of the present invention.

16 , the reception apparatus 300 includes a reception unit 310 and a signal processing unit 320 .

The receiver 310 receives signals from the first transmitter and the second transmitter during first and second time intervals.

The signal processing unit 320 separates the first and second superimposed coded signals received from the first and second transmission devices by multiplying the signals received during the first and second time intervals by a preset orthogonal code component. Here, the orthogonal code component is a component known between the receiving apparatus 300 and the first and second transmitting apparatuses, and is an orthogonal code component transmitted by multiplying the first and second overlapping coding signals by the first and second transmitting apparatuses may be an inverse component of Here, the first and second transmission devices may be implemented as the transmission device 100 or 200 illustrated in FIG. 12 or FIG. 13 , respectively. A detailed method of separating the received signal from the first and second transmitting apparatuses by multiplying the received signal by an orthogonal code has been described above based on the above equation, and thus a detailed description thereof will be omitted.

Meanwhile, the signal processing unit 320 may include a demapper that demodulates the separated first overlapping coded signal, a deinterleaver that deinterleaves the output of the demapper, and a decoder that decodes the output of the deinterleaver. Here, the first overlapping signal may be a signal overlapped by a layered division multiplexing (LDM) method by allocating different powers to the first and second signals to be transmitted by the first transmitting apparatus. In this case, the first and second signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively. In addition, the second overlapping signal may be a signal overlapped by the LDM method by allocating different powers to the third and fourth signals to be transmitted by the second transmitting apparatus.

17 is a block diagram showing the configuration of a receiving apparatus according to another embodiment of the present invention.

As shown in FIG. 17 , the receiving apparatus 1000 according to another embodiment of the present invention includes an OFDM receiving unit 1010 , a time deinterleaver 1020 , a gain controller 1030 , a buffer 1040 , and a signal removing unit 1050 . ), a base layer gain controller 1060 , a first signal processor 1070 , and a second signal processor 1080 .

First, the receiving apparatus 1000 may separate the first and second superimposed coded signals received from the first and second transmitting apparatuses by multiplying a predetermined orthogonal code component by a signal received during the first and second time intervals. have.

The OFDM receiver 1010 generates cells from the OFDM frame by performing OFDM demodulation on the overlapped coding signal transmitted by the first transmission apparatuses 100 and 200 , that is, the first overlapping signal, and outputs it to the time deinterleaver 1020 . can do.

The time deinterleaver 1020 deinterleaves the output of the OFDM receiver 1010 .

Specifically, the time deinterleaver 1020 may have a configuration corresponding to the time interleaver 250 of the transmitting apparatus 200 , interleave cells, and output the interleaved cells to the gain controller 1030 .

The gain controller 1030 adjusts a gain for the output of the time deinterleaver 1020 .

Specifically, the gain controller 1030 has a configuration corresponding to the gain controller 240 of the transmitter 200, and adjusts a gain for a signal output from the time deinterleaver 1020, and controls the gain-controlled signal. 1 is output to the signal processing unit 1070 and the buffer 1040 .

The first signal processing unit 1000 may generate a first signal by processing a signal output from the gain controller 1030 . Here, the first signal may be a signal corresponding to the upper layer.

Meanwhile, the buffer 1040 stores a signal output from the gain controller 1030 .

In addition, the signal removing unit 1050 removes the signal output from the first signal processing unit 1070 from the signal provided from the buffer 1040 , that is, the overlapping coding signal, and outputs it to the base layer gain controller 1060 .

Here, the first signal processing unit 1070 includes a first demapper 1071 , a first deinterleaver 1072 , and a first decoder 1073 , each of which is a first mapper 213 of the transmitting apparatus 200 . ), the reverse process of the first interleaver 212 and the first encoder 211 may be performed.

The base layer gain controller 1060 is a configuration corresponding to the base layer gain controller 230 in the transmitting device 200, and adjusts a gain for a signal output from the signal remover 1050, and adjusts the gain to the second signal processing unit ( 1080) is output.

The second signal processing unit 1080 may generate a second signal by processing the overlapping coding signal. Here, the second signal may be a signal corresponding to the base layer.

To this end, the second signal processing unit 1080 may include a second demapper 1081 , a second deinterleaver 1082 , and a second decoder 1083 . Here, the second demapper 1081 , the second deinterleaver 1082 , and the second decoder 1083 respectively include the second mapper 223 , the second interleaver 222 and the second encoder 10 of the transmitting apparatus 200 . 221), the reverse process can be performed.

The second demapper 1081 demodulates the signal from which the signal output from the first signal processing unit 1070 is removed from the overlapped coding signal.

Specifically, the second demapper 1081 demodulates a signal from which the signal output from the first signal processing unit 1070 is removed from the overlapped coding signal to generate an LLR value, and outputs it to the second deinterleaver 1081 . .

In this case, the second demapper 410 performs demodulation on the signal from which the signal output from the first signal processing unit 1070 is removed from the overlapped coding signal based on the modulation method applied to the signal corresponding to the base layer. can For example, when the transmitting apparatus 200 modulates a signal corresponding to the base layer using the 64-QAM method, the second demapper 1081 performs the first signal processing unit ( 1070), demodulation may be performed on the signal from which the signal is removed.

Here, the LLR value may be expressed as a value obtained by taking Log of the ratio of the probability that the bit transmitted from the transmitter 200 is 0 and the probability that it is 1. Alternatively, the LLR value may be a representative value determined according to a section to which the probability that the bit transmitted from the transmitting apparatus 200 is 0 or 1 belongs.

The second deinterleaver 1082 deinterleaves the output of the second demapper 1081 .

Specifically, the second deinterleaver 1082 has a configuration corresponding to the second interleaver 222 of the transmitting apparatus 200 , and deinterleaves the LLR values by inversely performing the interleaving operation performed in the second interleaver 222 . and output this to the second decoder 1083 .

The second decoder 1083 decodes the output of the second deinterleaver 1082 to reconstruct the signal.

18 is a flowchart illustrating a control method of a transmitting apparatus according to an embodiment of the present invention.

According to the control method of the transmitting apparatus shown in FIG. 18, first, the first and second signals are overlap-coded to generate an overlap-coded signal (S1810).

Then, the overlapped coding signal is multiplied by a preset orthogonal code component and transmitted (S1820).

In addition, in step S1810 of generating the overlapped coded signal, the first and second signals may be overlapped in a layered division multiplexing (LDM) manner by allocating different powers to generate the overlapped coded signal.

Here, the first and second signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively.

19 is a flowchart illustrating a control method of a transmitting apparatus according to an embodiment of the present invention.

According to the control method of the transmitting apparatus shown in FIG. 19, signals are received from the first transmitting apparatus and the second transmitting apparatus during the first and second time intervals (S1910).

Next, the first and second superimposed coded signals received from the first and second transmitters are separated by multiplying the signals received during the first and second time intervals by a preset orthogonal code component (S1920). Here, the orthogonal code component is a component known between the receiving device and the first and second transmitting devices, and is an inverse component of the orthogonal code component transmitted by multiplying the first and second overlapping coding signals by the first and second transmitting devices. can be

The method may further include performing demodulation on the separated first overlapping coding signal, performing the demodulated deinterleaving, and decoding the deinterleaved signal. Here, the first overlapping signal may be a signal that is overlapped by a layered division multiplexing (LDM) method by allocating different powers to the first and second signals. In this case, the first and second signals may be a mobile broadcast signal and a terrestrial broadcast signal, respectively.

On the other hand, the above-described method for controlling a transmitting apparatus and a receiving apparatus according to various embodiments of the present invention is implemented as a computer-executable program code and stored in various non-transitory computer readable media. It may be provided to a transmitting device and a receiving device to be executed by

In addition, although a bus is not illustrated in the above-described block diagram of the transmitting apparatus and the receiving apparatus, communication between each component in each apparatus may be performed through a bus. In addition, each device may further include a processor such as a CPU, a microprocessor, etc. that performs the various steps described above.

The non-transitory readable medium refers to a medium that stores data semi-permanently, rather than a medium that stores data for a short moment, such as a register, cache, memory, etc., and can be read by a device. Specifically, the above-described various applications or programs may be provided by being stored in a non-transitory readable medium such as a CD, DVD, hard disk, Blu-ray disk, USB, memory card, ROM, and the like.

In addition, although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims In addition, various modifications may be made by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

100: transmitting device 110: signal processing unit
120: transmitter 300: receiver device
310: receiving unit 320: signal processing unit

Claims (18)

delete delete delete delete In a communication system comprising a transmitting device for transmitting a signal in a layered division multiplexing (LDM) scheme and a receiving device for receiving the signal,
A first transmission device and a second transmission device each comprising: a signal processing unit that allocates different powers to each of a mobile broadcast signal and a terrestrial broadcast signal to generate a superimposed coded signal by superimposing them in an LDM method; and a transmitter that transmits the superposed coded signal. Device; and
A receiver for receiving signals during a first time interval and a second time interval from the first transmitting apparatus and the second transmitting apparatus, and multiplying a predetermined orthogonal code component by a predetermined orthogonal code component by a signal received during the first and second time intervals A receiving apparatus including a first transmitting apparatus and a signal processing unit for processing the signal by separating the first and second overlapping coded signals received from the first transmitting apparatus and the second transmitting apparatus; and
The signal processing unit included in the first transmission device and the second transmission device,
a first signal processing unit for signal processing the mobile broadcasting signal;
a second signal processing unit for signal processing the terrestrial broadcast signal;
a first gain controller for adjusting the power of the terrestrial broadcast signal output from the second signal processing unit;
a second gain controller that adjusts the power of the superimposed coding signal by overlapping the power-adjusted terrestrial broadcast signal and the signal-processed mobile broadcast signal;
The transmission unit included in the first transmission device and the second transmission device,
Transmitting the power-adjusted superimposed coding signal to the receiving device,
The first overlapped coding signal is a signal that is superimposed in an LDM method by allocating different powers to a mobile broadcast signal multiplied by a first Signed Identity Matrix and a terrestrial broadcast signal multiplied by a second Signed Identity Matrix,
The second superimposed coded signal is a signal superimposed in an LDM method by allocating different powers to a mobile broadcast signal multiplied by a third Signed Identity Matrix and a terrestrial broadcast signal multiplied by a fourth Signed Identity Matrix,
The signal processing unit included in the receiving device,
a first gain controller for adjusting the power of the first superposition coded signal;
a first signal processing unit configured to obtain the mobile broadcast signal based on a first superposition coded signal whose power is adjusted by the first gain controller;
a signal removing unit for removing the mobile broadcast signal from the first superimposed coding signal of which the power is adjusted;
a second gain controller for adjusting the power of the first superposition coded signal from which the mobile broadcast signal is removed; and
a second signal processing unit configured to obtain the terrestrial broadcast signal from the first superimposed coded signal whose power is adjusted by the second gain controller;
The orthogonal code component is
It is a known component between the receiving device and the first and second transmitting devices,
A communication system, characterized in that it is an inverse matrix of a matrix generated based on the signs of the first, second, third and fourth Signed Identity Matrix. delete 6. The method of claim 5,
The signal processing unit included in the receiving device,
a demapper that demodulates the first superposition coded signal;
a deinterleaver for deinterleaving the output of the demapper; and
A communication system comprising a; decoder for decoding the output of the deinterleaver. delete delete delete delete delete In the control method of a receiving device for receiving the first and second superimposed coded signals transmitted from the first and second transmitting devices,
receiving signals from the first transmitting device and the second transmitting device during first and second time intervals; and,
Separating and signal processing the first and second superimposed coded signals received from the first transmitting apparatus and the second transmitting apparatus by multiplying a predetermined orthogonal code component by a signal received during the first and second time intervals; includes,
The first overlapped coding signal is a signal that is superimposed in an LDM method by allocating different powers to a mobile broadcast signal multiplied by a first Signed Identity Matrix and a terrestrial broadcast signal multiplied by a second Signed Identity Matrix,
The second superimposed coded signal is a signal superimposed in an LDM method by allocating different powers to a mobile broadcast signal multiplied by a third Signed Identity Matrix and a terrestrial broadcast signal multiplied by a fourth Signed Identity Matrix,
The signal processing step is
adjusting the power of the first superposition coded signal;
removing the mobile broadcast signal from the power-adjusted first superposition coded signal;
adjusting the power of the first superposition coded signal from which the mobile broadcast signal is removed; and
Including; obtaining the terrestrial broadcast signal from the first superposition coded signal from which the mobile broadcast signal is removed and power is adjusted;
The orthogonal code component is
It is a known component between the receiving device and the first and second transmitting devices,
A control method, characterized in that it is an inverse matrix of a matrix generated based on the signs of the first, second, third and fourth Signed Identity Matrix. delete 14. The method of claim 13,
performing demodulation on the first superposition coded signal;
deinterleaving the demodulated signal; and
Decoding the deinterleaved signal; further comprising, the control method. delete delete delete

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