KR100903877B1 - Apparatus and method for receiving signal in digital broadcasting system - Google Patents

Abstract

The signal receiving apparatus receives a plurality of signals through a plurality of antennas, generates a first layer estimation symbol sequence and a plurality of second layer estimation symbol sequences from the plurality of signals, and applies weights to the plurality of second layer estimation symbol sequences. To generate a plurality of weighted symbol strings. Subsequently, an addition operation is performed on the plurality of weighted symbol strings to generate a diversity signal, a first layer signal is generated based on the first layer estimate symbol string, and a second layer signal is generated based on the diversity signal. . This can increase the reception of newly added signals.

Broadcast, Hierarchical Modulation, Diversity, OFDM

Description

Apparatus and method for receiving signal in digital broadcasting system {APPARATUS AND METHOD FOR RECEIVING SIGNAL IN DIGITAL BROADCASTING SYSTEM}

The present invention relates to a signal receiving apparatus and method in a digital broadcasting system. In particular, the present invention relates to a signal receiving apparatus and method in a digital broadcasting system employing a hierarchical modulation scheme.

The present invention is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Information and Communication and the Ministry of Information and Telecommunication Research and Development. [Task Management No .: 2006-S-017-02, Title: Development of Advanced Terrestrial DMB Transmission Technology] .

In the digital broadcasting system, in order to increase the quality of a service or to increase the number of service channels, a high channel rate is required.

To this end, the digital broadcasting system can obtain a high channel rate through hierarchical modulation. Hierarchical modulation is a method of modulating two independent signals modulated by different modulation methods into one signal.

In this case, in a digital broadcasting system using a hierarchical modulation method, a signal of an existing digital broadcasting system is called a high priority signal (hereinafter referred to as an HP signal), and a newly added signal is a low priority signal (Low). Priority Signal (hereinafter, also referred to as 'LP signal'), in order to maintain compatibility with a digital broadcasting system using a hierarchical modulation scheme, the LP signal should be smaller than the size of the HP signal.

However, since the magnitude of the LP signal is smaller than that of the HP signal, the LP signal has a problem that signal distortion occurs due to multipath interference, and the reception rate is lower than that of the HP signal due to weak noise.

An object of the present invention is to provide an apparatus and method for increasing a reception ratio of a signal newly added to a signal of an existing digital broadcasting system.

According to an aspect of the present invention, there is provided a method of receiving a signal through a plurality of antennas, the method comprising: receiving a plurality of signals through a plurality of antennas; Generating a hierarchical estimation symbol string, generating a plurality of weighted symbol strings by applying weights to each of the plurality of second hierarchical symbol symbol strings, and performing an addition operation on the plurality of weighted symbol strings to generate a diversity signal. Generating a first layer signal based on the first hierarchical estimated symbol string; and generating a second layer signal based on the diversity signal.

The generating of the first hierarchical estimation symbol sequence and the second hierarchical estimation symbol sequence may include differentially demodulating one of the plurality of signals to generate a first hierarchical estimation symbol sequence and generating the first hierarchical estimation symbol sequence. Extracting a second layer estimation symbol sequence from the signal based on the signal;

The extracting may include: generating a symbol demapping signal by symbol demapping the first hierarchical estimation symbol sequence, generating a channel decoded signal by channel decoding the symbol demapping signal, and symbol mapping by symbol mapping the channel decoded signal. Generating a signal and extracting a second layer estimated symbol string from the signal based on the symbol mapping signal.

The generating of the plurality of weighted symbols may include calculating energy for each of the plurality of estimated symbol strings, and calculating weights for each of the plurality of estimated symbol strings based on energy for each of the plurality of estimated symbol strings. And generating a plurality of weighted symbol strings by applying a weight to each of the plurality of estimated symbol strings according to the weights for each of the plurality of estimated symbol strings.

In addition, the first layer signal corresponds to a signal having a higher priority than the second layer signal.

The generating of the first layer signal may include generating a first layer symbol demapping signal by symbol demapping the first layer estimation symbol string, and generating a first layer signal by channel decoding the first layer symbol demapping signal. It includes a step.

The generating of the second layer signal may include generating a second layer symbol demapping signal by symbol demapping the diversity signal, and generating a second layer signal by channel decoding the second layer symbol demapping signal. Include.

According to another aspect of the present invention, there is provided a method of receiving a signal through a plurality of antennas, the method comprising: receiving a plurality of signals through a plurality of antennas; Generating a two-layer estimated symbol string, calculating an energy for each of the plurality of second-layer estimated symbol strings, and a plurality of second-layer estimated symbol strings based on the energy for each of the plurality of second-layer estimated symbol strings. Selecting some of the second layer estimation symbol strings, symbol demapping each of the first layer estimation symbol strings, and the portion of the second layer estimation symbol strings, to form a first layer symbol demapping signal and a second layer symbol demapping signal. Generating a first layer signal and a second layer signal by channel decoding each of the first layer symbol demapping signal and the second layer symbol demapping signal. Include.

In this case, the selecting step selects the second hierarchical estimated symbol string having the largest energy among the plurality of second hierarchical estimated symbol strings.

Signal receiving apparatus according to another aspect of the present invention is a device for receiving a signal transmitted in a different path in a wireless channel using a plurality of antennas, a plurality of symbol estimation module, signal processor, first layer symbol demapping unit And a second layer symbol demapping unit, a first layer decoding unit, and a second layer decoding unit. The plurality of symbol estimation modules receive a plurality of frequency multiplexed signals through a plurality of antennas and output a first layer estimation symbol string and a plurality of second layer estimation symbol strings. The signal processor outputs a diversity signal by processing the diversity signal on the plurality of second layer estimation symbol strings. The first layer symbol demapping unit symbol demaps the first layer estimation symbol string to output a first layer symbol demapping signal. The second layer symbol demapping unit symbol demaps the diversity signal and outputs a second layer symbol demapping signal. The first layer decoder performs channel decoding on the first layer symbol demapping signal and outputs a first layer decoded signal. The second layer decoding unit performs channel decoding on the second layer symbol demapping signal and outputs a second layer decoded signal.

In this case, each of the plurality of symbol estimation modules includes a receiver for receiving a frequency multiplexed signal through an antenna, a frequency multiplexing demodulator for generating a frequency multiplexed demodulation signal by Fourier transforming the frequency multiplexed signal, and a first layer by differentially demodulating the frequency multiplexed demodulated signal. A differential demodulator outputs an estimated symbol string and a symbol extractor extracts a second layer estimated symbol string from a frequency multiplexed demodulation signal based on the first layer estimated symbol string.

Each of the plurality of symbol estimation modules includes a symbol demapping unit for symbol demapping a first hierarchical estimation symbol sequence to output a symbol demapping signal, a decoder for channel decoding a symbol demapping signal, and a channel decoding signal for outputting a channel decoded signal. The symbol mapping unit outputs a symbol mapping signal by symbol mapping the decoded signal, and the symbol extractor extracts a second layer estimation symbol sequence from the frequency multiplexed demodulation signal based on the symbol mapping signal.

In addition, the signal processor outputs a diversity signal by using a maximum ratio combined diversity scheme, an equal gain combined diversity scheme, or a selective diversity scheme.

According to an aspect of the present invention, a diversity scheme may be applied in a digital broadcasting system using a hierarchical modulation scheme to increase a reception rate of a newly added signal.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, the terms “… unit”, “… unit”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. have.

A device and method for receiving a signal in a digital broadcasting system according to an embodiment of the present invention will now be described with reference to the drawings.

First, a signal transmission apparatus of a digital broadcasting system employing a hierarchical modulation scheme according to an embodiment of the present invention will be described with reference to FIG. 1.

1 is a diagram showing the configuration of a signal transmission apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the signal transmission apparatus 100 according to an embodiment of the present invention may include a first hierarchical code unit 110, a second hierarchical code unit 120, a first hierarchical symbol mapping unit 130, The second hierarchical symbol mapping unit 140, the hierarchical modulator 150, the orthogonal frequency division multiplexing modulator (hereinafter, also referred to as an 'OFDM modulator') 160 and the transmitter 170 are described. Include.

The first layer coder 110 performs channel encoding on a high priority signal (hereinafter, referred to as an “HP signal”) composed of a bit string, and includes a first encoding including a plurality of encoded bits. Output the signal.

The second hierarchical coder 120 channel-codes a low priority signal (hereinafter, referred to as an LP signal) formed of a bit string and outputs a second coded signal including a plurality of encoded bits. .

In this case, the first hierarchical channel encoder 110 and the second hierarchical channel encoder 120 may include convolution coding, trellis coding, turbo coding, low density parity check (LDPC) coding, Alternatively, a signal may be encoded by a method such as concatenated encoding in which two or more of them are concatenated with each other. Also, the first hierarchical channel encoder 110 and the second hierarchical channel encoder 120 may encode signals using different encoding methods.

The first hierarchical symbol mapping unit 130 performs symbol mapping on a plurality of encoded bits included in the first coded signal, and outputs a first symbol string including a plurality of symbols.

The second layer symbol mapping unit 140 performs symbol mapping on a plurality of encoded bits included in the second coded signal, and outputs a second symbol string including the plurality of symbols.

At this time, the first hierarchical symbol mapping unit 130 and the second hierarchical symbol mapping unit 140 are quadrature phase shift keying (QPSK), differential quadrature phase shift keying (DQPSK), and amplitude. Symbol mapping may be performed using an Amplitude Modulation (AM) or Quadrature Amplitude Modulation (QAM) method. In addition, the first layer symbol mapping unit 130 and the second layer symbol mapping unit 140 may perform symbol mapping in different ways.

The hierarchical modulator 150 hierarchically modulates the first symbol string and the second symbol string and outputs a hierarchical modulation signal including a plurality of hierarchical modulation symbols.

The OFDM modulator 160 performs an Orthogonal Frequency Division Multiplexing Signal (hereinafter referred to as an Inverse Fast Fourier Transform (IFFT)) for a plurality of hierarchical modulation symbols included in the hierarchical modulated signal. Also called 'OFDM signal').

The transmitter 170 transmits an OFDM signal through a wireless channel using an antenna.

Next, a signal receiving apparatus of a digital broadcasting system to which a hierarchical modulation scheme according to an embodiment of the present invention is applied will be described with reference to FIGS. 2 to 7.

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

As shown in FIG. 2, the signal receiving apparatus 200 includes a plurality of symbol estimation modules 210, a signal processor 220, a first layer symbol demapping unit 230, and a second layer symbol demapping unit 240. ), A first layer decoder 250 and a second layer decoder 260.

The plurality of symbol estimation modules 210 receives a plurality of OFDM signals through a plurality of antennas corresponding to the plurality of symbol estimation modules 210, respectively, to thereby obtain one first layer estimation symbol sequence and a plurality of second layer estimation symbol sequences. Extract In this case, the first hierarchical estimation symbol sequence corresponds to the first symbol sequence output by the first hierarchical symbol mapping unit 130 of the signal transmission apparatus 100, and each of the plurality of second hierarchical estimation symbol sequences is the signal transmission apparatus 100. The second layer symbol mapping unit 140 corresponds to the second symbol string output.

Hereinafter, a symbol estimation module according to an embodiment of the present invention will be described with reference to FIGS. 3 and 4.

3 is a diagram illustrating a configuration of a symbol estimation module according to an embodiment of the present invention.

As shown in FIG. 3, the symbol estimation module 211 includes a receiver 211a, an orthogonal frequency division multiplexing demodulator (hereinafter also referred to as an 'OFDM demodulator') 211b, a differential demodulator 211c and a symbol extraction unit 211d.

The receiver 211a receives an OFDM signal through an antenna.

The OFDM demodulator 211b performs a fast Fourier transform (hereinafter, also referred to as an 'FFT') on the received OFDM signal, and includes an orthogonal frequency division multiplexing demodulation signal including a plurality of symbols. Also called 'OFDM demodulation signal'. In this case, the OFDM demodulator 211b corresponds to the OFDM modulator 160 of the signal transmission apparatus 100, and the OFDM demodulated signal corresponds to a hierarchical modulated signal input to the OFDM modulator 160 and included in the OFDM demodulated signal. The plurality of symbols to be referred to correspond to the plurality of hierarchical modulation symbols included in the hierarchical modulation signal.

The differential demodulator 211c performs differential demodulation on the OFDM demodulated signal and outputs a first hierarchical estimated symbol string including a plurality of symbols. In this case, the differential demodulation unit 211c may transmit the first layer estimation symbol string to the first layer symbol demapping unit 230.

The symbol extractor 211d extracts a second layer estimation symbol string including a plurality of symbols from the OFDM demodulation signal based on the first layer estimation symbol string. In this case, the symbol extractor 211d may transmit the second layer estimation symbol string to the signal processor 220.

4 is a diagram illustrating a configuration of a symbol estimation module according to another example of an embodiment of the present invention.

As shown in FIG. 4, the symbol estimation module 213 includes a receiver 213a, an OFDM demodulator 213b, a differential demodulator 213c, a symbol demapping unit 213d, a decoder 213e, and a symbol mapping. Section 213f and symbol extraction section 213g.

The receiver 213a receives an OFDM signal through an antenna.

The OFDM demodulator 213b FFTs the received OFDM signal and outputs an OFDM demodulated signal including a plurality of symbols. In this case, the OFDM demodulator 213b corresponds to the OFDM modulator 160 of the signal transmission apparatus 100, and the OFDM demodulated signal corresponds to a hierarchical modulated signal input to the OFDM modulator 160 and included in the OFDM demodulated signal. The plurality of symbols to be referred to correspond to the plurality of hierarchical modulation symbols included in the hierarchical modulation signal.

The differential demodulator 213c differentially demodulates the OFDM demodulated signal and outputs a first hierarchical estimated symbol string including a plurality of symbols. In this case, the differential demodulator 213c may transmit the first hierarchical estimation symbol sequence to the first hierarchical symbol demapping unit 230.

The symbol demapping unit 213d symbol demaps the first hierarchical estimation symbol sequence and outputs a symbol demapping signal including a plurality of bits.

The decoder 213e channel decodes the symbol demapping signal and outputs a channel decoded signal including a plurality of bits.

The symbol mapping unit 213f symbol-maps the channel decoded signal and outputs a symbol mapping signal including a plurality of symbols.

The symbol extractor 213g extracts a second hierarchical estimated symbol string including a plurality of symbols from the OFDM demodulated signal based on the symbol mapping signal. In this case, the symbol extractor 213g may transmit the second layer estimation symbol string to the signal processor 220.

Referring to FIG. 2 again, a signal receiving apparatus of a digital broadcasting system employing a hierarchical modulation scheme according to an embodiment of the present invention will be described.

The signal processor 220 receives a plurality of second hierarchical estimation symbol sequences from the plurality of symbol estimation modules 210, processes a plurality of second hierarchical estimation symbol sequences by a diversity signal, and outputs a diversity signal. . In this case, the signal processor 220 may output a diversity signal by using a maximum ratio combined diversity scheme, an equal gain combined diversity scheme, or a selection diversity scheme.

Hereinafter, a signal processor according to an exemplary embodiment of the present invention will be described with reference to FIGS. 5, 6, and 7.

5 is a diagram illustrating a configuration of a signal processor to which the maximum ratio combined diversity scheme according to an embodiment of the present invention is applied.

As shown in FIG. 5, the signal processor 221 includes an energy calculator 221a, a weight calculator 221b, a weight applier 221c, and a diversity signal generator 221d.

The energy calculator 221a receives a plurality of second layer estimation symbol strings from the plurality of symbol estimation modules 210 and calculates energy for each of the plurality of second layer estimation symbol strings.

The weight calculator 221b calculates a weight for each of the plurality of second layer estimation symbol strings based on the energy for each of the plurality of second layer estimation symbol strings.

The weight applying unit 221c applies a weight to each of the plurality of second layer estimation symbol strings according to the weight for each of the plurality of second layer estimation symbol strings, and applies a plurality of weights corresponding to the plurality of second layer estimation symbol strings, respectively. Print a string of symbols.

The diversity signal generator 221d outputs a diversity signal including a plurality of symbols by performing an addition operation on the plurality of weighted symbol strings. In this case, the diversity signal generator 221d may transmit the diversity signal to the second layer symbol demapping unit 240.

6 is a diagram illustrating a configuration of a signal processing unit to which the same gain combining diversity scheme is applied according to another embodiment of the present invention.

As shown in FIG. 6, the signal processor 223 includes a weight applier 223a and a diversity signal generator 223b.

The weight applying unit 223a receives a plurality of second hierarchical estimation symbol sequences from the plurality of symbol estimation modules 210, applies the same weight to each of the plurality of second hierarchical estimation symbol sequences, and then applies the plurality of second hierarchical estimation symbols. A plurality of weighted symbol strings respectively corresponding to the column are output.

The diversity signal generator 223b performs an addition operation on the plurality of weighted symbol strings and outputs a diversity signal including a plurality of symbols. In this case, the diversity signal generator 223b may transmit the diversity signal to the second layer symbol demapping unit 240.

FIG. 7 is a diagram illustrating a configuration of a signal processing unit to which a selection diversity scheme is applied according to another embodiment of the present invention.

As shown in FIG. 7, the signal processor 225 includes an energy calculator 225a and a diversity signal generator 225b.

The energy calculator 225a receives a plurality of second layer estimation symbol strings from the plurality of symbol estimation modules 210 and calculates energy for each of the plurality of second layer estimation symbol strings.

The diversity signal generator 225b selects one second layer estimation symbol string among the plurality of second layer estimation symbol strings based on the energy of each of the plurality of second layer estimation symbol strings, and selects the selected second layer estimation. Outputs a diversity signal corresponding to a symbol string. In this case, the diversity signal generator 225b may transmit the diversity signal to the second layer symbol demapping unit 240.

Referring to FIG. 2 again, a signal receiving apparatus of a digital broadcasting system employing a hierarchical modulation scheme according to an embodiment of the present invention will be described.

The first hierarchical symbol demapping unit 230 receives a first hierarchical estimation symbol sequence from a symbol estimation module of one of the plurality of symbol estimation modules 210 and symbol demaps the first hierarchical estimation symbol sequence to generate a plurality of bits. Output a first layer symbol demapping signal comprising a. In this case, the first hierarchical symbol demapping unit 230 corresponds to the first hierarchical symbol mapping unit 130 of the signal transmission apparatus 100, and the first hierarchical symbol demapping signal is transmitted to the first hierarchical symbol mapping unit 130. The plurality of bits included in the first coded signal and the first layer symbol demapping signal correspond to the plurality of coded bits included in the first coded signal. Also, the first hierarchical symbol demapping unit 230 may output a first hierarchical symbol demapping signal through a symbol demapping scheme corresponding to a method of symbol mapping by the first hierarchical symbol mapping unit 130.

The second layer symbol demapping unit 240 receives the diversity signal from the signal processing unit 220, and symbolly demaps the diversity signal to output a second layer symbol demapping signal including a plurality of bits. In this case, the second hierarchical symbol demapping unit 240 corresponds to the second hierarchical symbol mapping unit 140 of the signal transmission apparatus 100, and the second hierarchical symbol demapping signal is transmitted to the second hierarchical symbol mapping unit 140. The plurality of bits included in the second coded signal and the plurality of bits included in the second layer symbol demapping signal correspond to the plurality of coded bits included in the second coded signal. In addition, the second layer symbol demapping unit 240 may output the second layer symbol demapping signal through a symbol demapping method corresponding to a method of symbol mapping by the second layer symbol mapping unit 140.

The first layer decoder 250 channel-decodes the first layer symbol demapping signal and outputs a first layer decoded signal including a plurality of bits. In this case, the first hierarchical decoding unit 250 corresponds to the first hierarchical code unit 110 of the signal transmission apparatus 100, and the first hierarchical decoding signal corresponds to the HP signal input to the first hierarchical code unit 110. Corresponds. In addition, the first hierarchical decoder 250 may output the first hierarchical decoded signal through a decoding method corresponding to a method encoded by the first hierarchical code unit 110.

The second layer decoder 260 channel-decodes the second layer symbol demapping signal and outputs a second layer decoded signal including a plurality of bits. In this case, the second layer decoder 260 corresponds to the second layer coder 120 of the signal transmission apparatus 100, and the second layer decoded signal corresponds to the LP signal input to the second layer coder 120. do. In addition, the second layer decoder 260 may output the second layer decoded signal through a decoding method corresponding to the method of encoding by the second layer channel encoder 120.

Next, a method of transmitting a signal by a signal transmission apparatus of a digital broadcasting system applying a hierarchical modulation scheme according to an embodiment of the present invention will be described with reference to FIG. 8 or 9.

8 is a diagram illustrating a signal transmission method according to an embodiment of the present invention.

As shown in FIG. 8, first, the signal transmission apparatus 100 receives an HP signal and an LP signal (S100). At this time, the HP signal has a higher priority than the LP signal, and the LP signal has a lower priority than the HP signal. In addition, the HP signal may correspond to a signal of a conventional T-DMB system, and the LP signal may correspond to a signal added to the HP signal.

Next, the signal transmission apparatus 100 performs channel encoding on the HP signal and the LP signal to generate a first coded signal corresponding to the HP signal and a second coded signal corresponding to the LP signal (S110).

In this case, the first layer encoder 110 of the signal transmission apparatus 100 may generate a first coded signal including a plurality of bits by channel coding the bit string constituting the HP signal (S111).

In addition, the second layer encoder 120 of the signal transmission apparatus 100 may channel encode a bit string constituting the LP signal to generate a second coded signal including a plurality of bits (S113).

Thereafter, the signal transmission apparatus 100 generates a first symbol string corresponding to the first coded signal and a second symbol string corresponding to the second coded signal by symbol mapping the first coded signal and the second coded signal (S120). ).

In this case, the first symbol mapping unit 130 of the signal transmission apparatus 100 may generate a first symbol string including a plurality of symbols by symbol mapping a plurality of bits included in the first coded signal (S121).

In addition, the second symbol mapping unit 140 of the signal transmission apparatus 100 may generate a second symbol string including a plurality of symbols by symbol mapping a plurality of bits included in the second coded signal (S123).

Next, the hierarchical modulator 150 of the signal transmission apparatus 100 hierarchically modulates the first symbol string and the second symbol string to generate a hierarchical modulated signal including a plurality of hierarchical modulation symbols (S130).

Hereinafter, the constellation of the hierarchical modulation signal according to an embodiment of the present invention will be described with reference to FIG. 9.

9 is a diagram illustrating a constellation of a hierarchical modulated signal according to an embodiment of the present invention.

In this case, by hierarchically modulating a first symbol string obtained by symbol-mapping a first coded signal corresponding to the HP signal in a DQPSK scheme, and a second symbol string formed by symbol-mapping a second coded signal corresponding to a LP signal in a π / 4-DQPSK scheme. The odd-numbered symbols of the generated hierarchical modulation signals may be shown as shown in FIG. 9A and the even-numbered symbols may be shown as shown in FIG. 9B.

Referring to FIG. 8 again, a method of transmitting a signal by a signal transmission apparatus of a digital broadcasting system applying a hierarchical modulation scheme according to an embodiment of the present invention will be described.

Thereafter, the OFDM modulator 160 of the signal transmission apparatus 100 generates an OFDM signal by IFFTting the plurality of hierarchical modulation symbols included in the hierarchical modulated signal (S140).

Next, the transmitter 170 of the signal transmitter 100 transmits an OFDM signal to the signal receiver 200 through a wireless channel by using one antenna (S150).

Next, a method of receiving a signal by a signal receiving apparatus of a digital broadcasting system applying a hierarchical modulation scheme according to an embodiment of the present invention will be described with reference to FIGS. 10 to 15.

10 is a diagram illustrating a signal reception method according to an embodiment of the present invention.

As shown in FIG. 10, first, the signal receiving apparatus 200 receives a plurality of OFDM signals through a plurality of antennas (S200).

Next, the plurality of symbol estimation modules 210 of the signal receiving apparatus 200 generates a first layer estimation symbol sequence and a plurality of second layer estimation symbol sequences based on the plurality of OFDM signals (S210).

Hereinafter, a method of generating a second layer estimation symbol string by the symbol estimation module according to an embodiment of the present invention will be described with reference to FIGS. 11 and 12.

FIG. 11 is a diagram illustrating a method of generating a second layer estimation symbol string, according to an embodiment of the present invention.

As shown in FIG. 11, first, the receiver 211a of the symbol estimation module 211 receives an OFDM signal through an antenna (S211a).

Next, the OFDM demodulator 211b of the symbol estimation module 211 generates an OFDM demodulated signal by FFTing the OFDM signal (S211b).

Thereafter, the differential demodulator 211c of the symbol estimation module 211 differentially demodulates the OFDM demodulated signal to generate a first hierarchical estimation symbol sequence (S211c).

Next, the symbol extraction unit 211d of the symbol estimation module 211 extracts a second layer estimation symbol sequence from the OFDM demodulation signal based on the first layer estimation symbol sequence (S211d).

12 is a diagram illustrating a method of generating a second layer estimation symbol string according to another embodiment of the present invention.

As shown in FIG. 12, first, the receiver 213a of the symbol estimation module 213 receives an OFDM signal through an antenna (S213a).

Next, the OFDM demodulator 213b of the symbol estimation module 213 performs FFT on the OFDM signal to generate an OFDM demodulated signal (S213b).

Thereafter, the differential demodulator 213c of the symbol estimation module 213 differentially demodulates the OFDM demodulated signal to generate a first hierarchical estimated symbol sequence (S213c).

Next, the symbol demapping unit 213d of the symbol estimation module 213 generates a symbol demapping signal by symbol demapping the first hierarchical estimation symbol sequence (S213d).

Thereafter, the decoder 213e of the symbol estimation module 213 performs channel decoding on the symbol demapping signal to generate a channel decoded signal (S213e).

Next, the symbol mapping unit 213f of the symbol estimation module 213 generates a symbol mapping signal by symbol mapping the channel decoded signal (S213f).

Subsequently, the symbol extractor 213g of the symbol estimation module 213 extracts the second layer estimation symbol string from the OFDM demodulation signal based on the symbol mapping signal (S213g).

Referring to FIG. 10 again, a method of receiving a signal by a signal receiving apparatus of a digital broadcasting system applying a hierarchical modulation scheme according to an embodiment of the present invention will be described.

Thereafter, the signal processor 220 of the signal receiving apparatus 200 generates a diversity signal by processing the diversity signal on the plurality of second layer estimation symbol strings (S220).

Hereinafter, a method of generating a diversity signal by the signal processor according to an exemplary embodiment of the present invention will be described with reference to FIGS. 13, 14, and 15.

13 is a diagram illustrating a diversity signal generation method according to one embodiment of the present invention.

As shown in FIG. 13, first, the energy calculator 221a of the signal processor 221 calculates energy for each of the plurality of second hierarchical estimated symbol strings (S221a).

Next, the weight calculator 221b of the signal processor 221 calculates a weight for each of the plurality of second layer estimation symbol sequences based on the energy for each of the plurality of second layer estimation symbol sequences (S221b).

Thereafter, the weight applying unit 221c of the signal processing unit 221 applies a weight to each of the plurality of second layer estimation symbol strings according to the weights for each of the plurality of second layer estimation symbol strings, thereby applying a plurality of weighted symbol strings. It generates (S221c).

Next, the diversity signal generator 221d of the signal processor 221 generates a diversity signal by performing an addition operation on the plurality of weighted symbol strings (S221d).

14 is a diagram illustrating a diversity signal generation method according to another example of an embodiment of the present invention.

As shown in FIG. 14, first, the weight applying unit 223a of the signal processing unit 223 generates a plurality of weighted symbols by applying the same weight to each of the plurality of second hierarchical estimated symbol strings (S223a).

Next, the diversity signal generator 223b of the signal processor 223 generates a diversity signal by performing an addition operation on the plurality of weighted symbols (S223b).

15 is a diagram illustrating a diversity signal generation method according to another example of an embodiment of the present invention.

As shown in FIG. 15, first, the energy calculator 225a of the signal processor 225 calculates energy for each of the plurality of second hierarchical estimated symbol strings (S225a).

Next, the diversity signal generator 225b of the signal processor 225 may perform the second layer estimation symbol having the largest energy among the plurality of second layer estimation symbol strings based on the energy of each of the plurality of second layer estimation symbol strings. The column is selected to generate a diversity signal including the selected estimated symbol string (S225b).

Referring to FIG. 10 again, a method of receiving a signal by a signal receiving apparatus of a digital broadcasting system applying a hierarchical modulation scheme according to an embodiment of the present invention will be described.

Next, the signal receiving apparatus 200 symbol demaps the first layer estimation symbol sequence and the diversity signal, and the second layer symbol corresponding to the first layer symbol demapping signal and the diversity signal corresponding to the first layer estimation symbol string. A demapping signal is generated (S230).

In this case, the first layer symbol demapping unit 230 of the signal receiving apparatus 200 may generate a first layer symbol demapping signal by symbol demapping the first layer estimation symbol string (S231).

In addition, the second layer symbol demapping unit 240 of the signal receiving apparatus 200 may generate a second layer symbol demapping signal by symbol demapping the diversity signal (S233).

Subsequently, the signal receiving apparatus 200 performs channel decoding on the first layer symbol demapping signal and the second layer symbol demapping signal to decode the first layer decoded signal and the second layer symbol demapping corresponding to the first layer symbol demapping signal. A second layer decoded signal corresponding to the signal is generated (S240).

In this case, the first layer decoder 250 of the signal receiving apparatus 200 may channel decode the first layer symbol demapping signal to generate a first layer decoded signal corresponding to the HP signal (S241).

In addition, the second layer decoder 260 of the signal receiving apparatus 200 may channel decode the second layer symbol demapping signal to generate a second layer decoded signal corresponding to the LP signal (S243).

Next, the performance of the diversity signal to which the maximum ratio combined diversity scheme is applied in the signal receiving apparatus according to the embodiment of the present invention will be described with reference to FIG. 16.

16 illustrates a diversity signal to which the maximum ratio combined diversity scheme according to an embodiment of the present invention is applied.

As shown in FIG. 16, when the frequency spectrum of the signal received through the two antennas Ant # 1 and Ant # 2 is analyzed, the deep nulls of the antennas Ant # 1 and the antenna #Ant # 2 are analyzed. The effect is that the depth of the null decreases very much after the two signals are combined.

The embodiments of the present invention described above are not implemented only through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. Implementation may be easily implemented by those skilled in the art from the description of the above-described embodiments.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a diagram showing the configuration of a signal transmission apparatus according to an embodiment of the present invention.

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

3 is a diagram illustrating a configuration of a symbol estimation module according to an embodiment of the present invention.

4 is a diagram illustrating a configuration of a symbol estimation module according to another example of an embodiment of the present invention.

5 is a diagram illustrating a configuration of a signal processor to which the maximum ratio combined diversity scheme according to an embodiment of the present invention is applied.

6 is a diagram illustrating a configuration of a signal processing unit to which the same gain combining diversity scheme is applied according to another embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration of a signal processing unit to which a selection diversity scheme is applied according to another embodiment of the present invention.

8 is a diagram illustrating a signal transmission method according to an embodiment of the present invention.

9 is a diagram illustrating a constellation of a hierarchical modulated signal according to an embodiment of the present invention.

10 is a diagram illustrating a signal reception method according to an embodiment of the present invention.

FIG. 11 is a diagram illustrating a method of generating a second layer estimation symbol string, according to an embodiment of the present invention.

12 is a diagram illustrating a method of generating a second layer estimation symbol string according to another embodiment of the present invention.

13 is a diagram illustrating a diversity signal generation method according to one embodiment of the present invention.

14 is a diagram illustrating a diversity signal generation method according to another example of an embodiment of the present invention.

15 is a diagram illustrating a diversity signal generation method according to another example of an embodiment of the present invention.

16 illustrates a diversity signal to which the maximum ratio combined diversity scheme according to an embodiment of the present invention is applied.

Claims (13)

In the method for receiving a signal through a plurality of antennas, Receiving a plurality of signals through the plurality of antennas; Generating a first layer estimation symbol string and a plurality of second layer estimation symbol strings from the plurality of signals; Generating a plurality of weighted symbol strings by applying a weight to each of the plurality of second layer estimation symbol strings; Generating a diversity signal by performing an addition operation on the plurality of weighted symbol strings; Generating a first layer signal based on the first layer estimate symbol sequence; And Generating a second layer signal based on the diversity signal. The method of claim 1, Generating the first hierarchical estimation symbol sequence and the second hierarchical estimation symbol sequence Differentially demodulating one of the plurality of signals to generate a first hierarchical estimated symbol sequence; And And extracting a second layer estimation symbol sequence from the one signal based on the first layer estimation symbol sequence. The method of claim 2, The extracting step Symbol demapping the first hierarchical estimation symbol sequence to generate a symbol demapping signal; Channel decoding the symbol demapping signal to generate a channel decoded signal; Symbol mapping the channel decoded signal to generate a symbol mapping signal; And And extracting the second layer estimation symbol sequence from the one signal based on the symbol mapping signal. The method of claim 1, Generating the plurality of weighted symbols Calculating an energy for each of the plurality of second hierarchical estimated symbol strings; Calculating weights for each of the plurality of second layer estimation symbol sequences based on energies for each of the plurality of second layer estimation symbol sequences; And And generating a plurality of weighted symbol strings by applying weights to each of the plurality of second layer estimated symbol strings according to the weights for each of the plurality of second layer estimated symbol strings. The method of claim 1, And the first layer signal corresponds to a signal having a higher priority than the second layer signal. The method of claim 1, Generating the first layer signal Symbol demapping the first hierarchical estimate symbol sequence to generate a first hierarchical symbol demapping signal; And And channel decoding the first layer symbol demapping signal to generate a first layer signal. The method of claim 1, Generating the second layer signal Symbol demapping the diversity signal to generate a second layer symbol demapping signal; And And channel decoding the second layer symbol demapping signal to generate the second layer signal. In the method for receiving a signal through a plurality of antennas, Receiving a plurality of signals through the plurality of antennas; Generating a first layer estimation symbol string and a plurality of second layer estimation symbol strings from the plurality of signals; Calculating an energy for each of the plurality of second hierarchical estimated symbol strings; Selecting a second layer estimation symbol sequence of a portion of the plurality of second layer estimation symbol sequences based on energy for each of the plurality of second layer estimation symbol sequences; Symbol demapping each of the first layer estimate symbol sequence and the portion of the second layer estimate symbol sequence to generate a first layer symbol demapping signal and a second layer symbol demapping signal; And And channel decoding each of the first layer symbol demapping signal and the second layer symbol demapping signal to generate a first layer signal and a second layer signal. The method of claim 8, The selecting step And selecting a second layer estimation symbol sequence having the largest energy among the plurality of second layer estimation symbol sequences. An apparatus for receiving a signal transmitted in different paths in a wireless channel using a plurality of antennas, A plurality of symbol estimation modules for receiving a plurality of frequency multiplexed signals through a plurality of antennas and outputting a first layer estimation symbol sequence and a plurality of second layer estimation symbol sequences; A signal processor for processing a plurality of second hierarchical estimated symbol strings by a diversity signal and outputting a diversity signal; A first hierarchical symbol demapping unit configured to symbol demap the first hierarchical estimation symbol sequence and output a first hierarchical symbol demapping signal; A second layer symbol demapping unit configured to symbol demap the diversity signal to output a second layer symbol demapping signal; A first hierarchical decoder for channel decoding the first hierarchical symbol demapping signal to output a first hierarchical decoded signal; And And a second layer decoder configured to channel decode the second layer symbol demapping signal to output a second layer decoded signal. The method of claim 10, Each of the plurality of symbol estimation modules A receiver which receives a frequency multiplexed signal through an antenna; A frequency multiplexing demodulator for performing a Fourier transform on the frequency multiplexed signal to generate a frequency multiplexed demodulation signal; A differential demodulator for differentially demodulating the frequency multiplexed demodulation signal to output a first hierarchical estimated symbol string; And And a symbol extractor configured to extract a second hierarchical estimated symbol sequence from the frequency multiplexed demodulation signal based on the first hierarchical estimated symbol sequence. The method of claim 11, Each of the plurality of symbol estimation modules A symbol demapping unit for symbol demapping the first hierarchical estimation symbol sequence and outputting a symbol demapping signal; A decoder for channel decoding the symbol demapping signal and outputting a channel decoded signal; And Further comprising a symbol mapping unit for symbol mapping the channel decoded signal to output a symbol mapping signal, The symbol extraction unit And a second hierarchical estimation symbol sequence is extracted from the frequency multiplexed demodulation signal based on the symbol mapping signal. The method of claim 10, And the signal processor outputs a diversity signal by using a maximum ratio combined diversity scheme, an equal gain combined diversity scheme, or a selective diversity scheme.

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