JP2004112792A - Channel equalizer for single carrier receiver and method of equalizing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a channel equalizer that has an improved equalizing performance. <P>SOLUTION: The channel equalizer has a feedforward filter for removing pre-ghosts of each symbol from broadcast signals, a feedback filter for removing post ghosts of each symbol from broadcast signals, and a compositing unit for summing the symbols of which pre-ghosts are removed and symbols of which post ghosts are removed. It further has a level determining unit for determining the symbols summed at the compositing unit as an applicable level value with reference to a set level to feedback the level value to the feedback filter, a trellis decoding unit for trellis decoding the symbols composited at the compositing unit, an error calculating unit for calculating the difference between the symbols summed at the compositing unit and those determined at the level determining unit, and a trellis control unit for controlling the trellis decoding unit so that a plurality of symbols outputted from the trellis decoding unit in response to the calculated difference value are inputted to the feedback filter. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a channel equalizer for a single carrier receiver, and more particularly, to a single carrier equalizing a received signal with respect to a channel environment using a plurality of decoded symbols provided from a trellis decoder. The present invention relates to a channel equalizer of a receiver and a method of equalizing the channel.

放送 As a transmission method of a broadcast signal when implementing digital broadcasting, there are a vestigial sideband (VSB) modulation method and a coded orthogonal frequency division multiplexing (COFDM) modulation method. The VSB modulation scheme is a modulation scheme for transmitting a broadcast signal in which a broadcast signal is transmitted using a single carrier. The COFDM modulation method is a modulation method for transmitting a broadcast signal that is obtained by multiplexing a broadcast signal and transmitting the multiplexed signal through a multiplex transmission channel. The vestigial sideband modulation scheme is a digital broadcasting transmission scheme for the United States adopted in South Korea and the United States, and the coded orthogonal frequency division multiplex modulation scheme is a digital broadcasting transmission scheme for Europe.

Currently, among the VSB modulation methods, the standard adopted for terrestrial digital television for the United States is ATSC-8VSB, which converts a broadcast signal for transmission into eight levels and transmits the signal. On the other hand, a VSB receiver for receiving a broadcast signal modulated and transmitted by the VSB modulation method includes a channel equalizer that equalizes distortion generated on a transmission channel with respect to a transmitted broadcast signal.

FIG. 1 is a diagram showing an example of a channel equalizer applied to a conventional single carrier receiver. As shown in the figure, the channel equalizer of the single carrier receiver has a feed-forward filter 10, a feedback filter 30, an adder 40, and a slicer 50. A channel equalizer having the feed-forward filter 10 and the feedback filter 30 is called a decision feedback equalizer (Decision Feedback Equalizer: DFE).

The feed forward filter 10 removes the influence of pre-ghost on each symbol of the broadcast signal. The feedback filter 30 removes the influence of post ghost on each symbol of the broadcast signal. The adder 40 adds the value from which the pre-ghost is removed by the feed forward filter 10 and the value from which the post-ghost is removed by the feedback filter 30.

In the slicer 50, the value added by the adding unit 40 is determined to be the signal level closest to the level based on the set level. The slicer 50 feeds back the determined level value to the feedback filter 30.

The feed-forward filter 10 includes a buffering unit 12, a multiplication unit 14, and a second addition unit 16. The buffering unit 12 sequentially stores and buffers the broadcast signals in the buffers in the order of input in symbol units. The multiplication unit 14 removes a pre-ghost by multiplying each symbol stored and buffered in each buffer of the buffering unit 12 by a feed-forward filter tap coefficient of an equalizer (not shown). The second adder 16 sums the values from which the pre-ghost has been removed by the multiplier 14.

The feedback filter 30 includes a buffering unit 32, a multiplying unit 34, and a third adding unit 36. The buffering unit 32 sequentially stores and buffers the level values determined by the slicer 50 in each buffer in the order of input in symbol units. The multiplication unit 34 removes a post ghost from each symbol stored and buffered in each buffer of the buffering unit 32. The third adder 36 adds up the values from which the post ghost has been removed. Next, the adder 40 adds the values added by the second adder 16 of the feed forward filter 10 and the third adder 36 of the feedback filter 30 respectively.

1 In the channel equalizer of FIG. 1, the level value determined by the slicer 50 is input as the input of the feedback filter 30. However, if an error occurs in determining the level value in the slicer 50, the erroneously determined level value is added to the output value of the feed forward filter 10 in the adding unit 40 via the feedback filter 30.

On the other hand, the slicer 50 has a difference in performance in determining a level value depending on the number of levels set for the broadcast signal. For example, when the number of levels is 8 VSB, ie, 8 levels, when the power value of both broadcast signals is the same, the interval between signal levels is reduced by half compared to 4 VSB, which is 4 levels. Therefore, there is a problem that the probability of occurrence of an error in the determination of the level value of the slicer 50 increases.

Therefore, there is a problem that the greater the error in determining the level value of the slicer 50, the more the error propagation phenomenon of the feedback filter 30 occurs. In addition, the signal-to-noise ratio of the broadcast signal is greatly reduced due to the error in determining the level value of the slicer 50, and the performance of the channel equalizer is deteriorated. As a result, the reception performance of the single carrier receiver is deteriorated as a whole. There is a problem.

Accordingly, TCM (Trellis Coded Modulation) for performing trellis decoding on a signal input to the channel equalizer may be applied to reduce performance degradation of the channel equalizer due to an error in determining the level value of the slicer 50.

FIG. 2 is a diagram showing another example of a channel equalizer applied to a conventional VSB receiver. As shown in the figure, the channel equalizer includes a feed-forward filter 10, a feedback filter 30, an adder 40, a slicer 50, a calculator 60, and a TCM unit 70.

The feed forward filter 10 removes the influence of pre-ghost on each symbol of the broadcast signal. The feedback filter 30 removes the influence of post ghost on each symbol of the broadcast signal. The adder 40 adds the value from which the pre-ghost is removed by the feed forward filter 10 and the value from which the post-ghost is removed by the feedback filter 30. In the slicer 50, the value added by the adding unit 40 is determined to be the signal level closest to the level based on the set level.

The calculation unit 60 calculates a difference value between the output value of the addition unit 40 and the output value of the slicer 50. The TCM unit 70 performs trellis decoding on the output value of the adding unit 40. At this time, the TCM unit 70 feeds back the trellis-decoded value to the feedback filter 30. As a result, the feedback filter 30 removes the post ghost of each symbol based on the trellis-decoded value fed back from the TCM unit 70.

However, the trellis-decoded value input to the feedback filter 30 causes a feedback delay due to the trellis decoding operation of the TCM unit 70, and the feedback filter 30 for a predetermined period of time outputs each symbol based on the value output from the slicer 50. Entered while removing post ghost. Therefore, the feedback filter 30 must remove the post ghost of each symbol based on the level value determined by the slicer 50 until the trellis-decoded value is input from the TCM unit 70. When deciding on a value, it is very likely that you will decide by mistake.

(4) Further, in a channel environment where a strong ghost exists in the broadcast signal before the output delay time of the TCM unit 70, equalization performance is hardly expected even if the channel equalizer to which the TCM unit 70 is applied.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to use a trellis-decoded signal to remove a ghost, and to reduce a signal output delay time due to a trellis decoding operation. And a channel equalizer of a VSB equalizer capable of improving the equalization performance even in a poor channel environment in which a strong ghost exists in a broadcast signal, and a channel equalization method using the same.

In order to achieve the above object, a channel equalizer of a single carrier receiver according to the present invention includes a feed forward filter for removing a pre-ghost of each symbol from a broadcast signal, and a symbol for each symbol from the broadcast signal. A feedback filter that removes the post-ghost, a combining unit that adds the symbol from which the pre-ghost is removed and the symbol from which the post-ghost is removed, and a symbol that is added by the combining unit. A level determining unit that determines a corresponding level value based on a level, and performs a trellis decoding on the symbol added by the combining unit and a level determining unit that feeds back the level value to the feedback filter. N is a natural number), and the symbol length of the entire traceback delay is N × K (K is a natural number) A trellis decoding unit, an error calculation unit that calculates an error between the symbol added by the synthesis unit by the set error update algorithm and the level value determined by the level determination unit, and a calculation by the error calculation unit The trellis decoding unit to input a plurality of decoded symbols output from a plurality of states of the entire decoding depth of the trellis decoding unit to the feedback filter in accordance with the error value. And a trellis control unit for controlling.

The trellis control unit, when the signal-to-noise ratio corresponding to the error value is equal to or greater than a set threshold, the trellis decoding unit outputs the plurality of states output from a plurality of states of the entire decoding depth. The trellis decoding unit is controlled so that the decoded symbol is input to the feedback filter.

Here, the decoded symbol output from the state where the decoding depth of the trellis decoding unit is n (n is equation (4)) is input to the 1+ (n × K) th filter tap of the feedback filter. Accordingly, the plurality of decoded symbols output from the plurality of states are respectively input to corresponding filter taps of the feedback filter.

That is, when the level value determined by the level determination unit is input, the feedback filter removes the post ghost for each symbol based on the level value, and outputs the plurality of signals from the trellis decoding unit. When a decoded symbol is input, the post ghost is removed based on the plurality of decoded symbols.

A channel equalization method for a single carrier receiver according to the present invention includes the steps of: removing a pre-ghost of each symbol for a broadcast signal with a feed forward filter; and removing a post-ghost of each symbol for the broadcast signal with a feedback filter. Removing the symbol from which the pre-ghost has been removed and the symbol from which the post-ghost has been removed; and determining the added symbol to a corresponding level value based on the set level. A feedback step of inputting the level value to the feedback filter; and a trellis decoder having a total decoding depth of N (N is a natural number) and a symbol length of the entire traceback delay of N × K (K is a natural number). The trellis decoding step for decoding and the set error update Calculating an error between the symbol added by a algorithm and the determined level value; and calculating a plurality of states of the decoding depth N of the trellis decoder corresponding to the calculated error value. Controlling whether to output the plurality of decoded symbols to the feedback filter.

The control step includes: when a signal-to-noise ratio corresponding to the error value is equal to or greater than a set threshold, a plurality of decodings output from a plurality of states of the overall decoding depth of the trellis decoder. The input symbol is input to the feedback filter.

Here, the decoded symbol output from the state where the decoding depth of the trellis decoder is n (n is equation (5)) is input to the 1+ (n × K) th filter tap of the feedback filter. Accordingly, the plurality of decoded symbols output from the plurality of states are respectively input to corresponding filter taps of the feedback filter.

That is, the feedback filter removes the post ghost for each symbol based on the level value, and when the plurality of decoded symbols are input from the trellis decoder, the plurality of decoded symbols Removing the post ghost based on the symbol.

Therefore, when the signal-to-noise ratio corresponding to the error value calculated by the error calculation unit is equal to or greater than the threshold, the feedback filter performs filtering based on the plurality of decoded values input from the trellis decoding unit, It is possible to reduce the deterioration of the equalization performance due to an error in determining the level value by the level determining unit.

According to the present invention, when the signal-to-noise ratio corresponding to the error value calculated by the error calculator becomes equal to or larger than the threshold, the feedback filter performs filtering based on the plurality of decoded values input from the trellis decoder. Thus, it is possible to reduce the deterioration of the equalization performance due to an error in determining the level value by the level determination unit.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
[Example]
FIG. 3 is a schematic block diagram of a VSB receiver according to the present invention. Hereinafter, the present invention will be described in detail using a VSB receiver as an example of a single carrier receiver.

As shown in FIG. 3, the VSB receiver includes a demodulator 81, a distortion compensator 82, a comb filter 83, a channel equalizer 84, a phase restorer 85, a trellis decoder 87, a deinterleaver 88, and a Reed-Solomon decoder. A portion 89 is provided.

The demodulation unit 81 converts the received broadcast signal in the RF band into a baseband. The distortion compensating unit 82 restores a segment synchronization signal, a field synchronization signal, a symbol timing, and the like for the broadcast signal output from the demodulation unit 81. The comb filter 83 removes the NTSC interference signal from the broadcast signal output from the demodulation unit 81.

The channel equalizer 84 compensates for channel distortion generated during transmission of a broadcast signal via a transmission channel. The phase restoration unit 85 restores the phase of the broadcast signal whose channel distortion has been compensated. The trellis decoding unit 87 performs trellis decoding on the broadcast signal whose phase distortion has been restored by the phase restoration unit 85. The deinterleaver 88 performs deinterleaving corresponding to the interleaving performed on the transmission side on the trellis-decoded broadcast signal. Reed-Solomon decoding section 89 performs decoding corresponding to Reed-Solomon encoding on the broadcast signal performed on the transmission side on the deinterleaved broadcast signal.

The trellis decoding unit 87 according to the present embodiment is, for example, as shown in FIG. The entire decoding depth of the trellis decoding unit 87 has states of 0, 1, 2, 3,..., N. When deinterleaving is performed in K (K is a natural number) symbol units, the entire trace The back delay length has a K × N symbol length. That is, the decoding depth of the trellis decoding unit 87 is arbitrarily set among the values (d ₀ , d ₁ ,..., D _n ) decoded in the state of 0, 1, 2, 3,. A plurality of decoded values, for example, d ₀ , d ₁ ,..., D _n (Equation (6)) are fed back to the channel equalizer 84. Therefore, the channel equalizer 84 performs channel equalization on each symbol based on the plurality of decoded values fed back from the trellis decoder 87.

FIG. 4 is a block diagram showing a preferred embodiment of a single carrier receiver capable of improving the equalization performance according to the present invention, for example, a channel equalizer of the VSB receiver shown in FIG.

As shown in FIG. 4, the channel equalizer includes a feed-forward filter 110, a feedback filter 120, a synthesizer 130, a trellis decoder 140 (trellis decoder 87 in FIG. 3), a level determiner 150, an error calculator 160, And a trellis control unit 170.

The feed-forward filter 110 removes the effect of pre-ghost on each symbol of the broadcast signal. The feedback filter 120 removes the effect of post ghost on each symbol of the broadcast signal. Here, a detailed configuration of the feed forward filter 110 and the feedback filter 120 is such that an input broadcast signal is sequentially buffered in symbol units, and a ghost is removed from each symbol buffered in each buffer (not shown). The structure is the same as that of the feed-forward filter 10 and the feedback filter 30 shown in FIG.

The combining unit 130 combines the value M from which the pre-ghost output from the feed forward filter 110 is removed and the value L from which the post-ghost output from the feedback filter 120 is removed. The trellis decoding section 140 performs trellis decoding on the value Y synthesized by the synthesis section 130.

The level determining unit 150 determines the value Y synthesized by the synthesizing unit 130 to be the closest signal level based on the set level. Accordingly, the level determining section 150 provides the determined level value D to the feedback filter 120 and the error calculating section 160. Here, the level determination unit 150 determines the level in accordance with a predetermined level of the set broadcast signal, for example, among the four levels, eight levels, and sixteen levels.

The error calculation unit 160 compares the output value Y of the synthesis unit 130 with the output value D of the level determination unit 150 according to the set error update algorithm, and compares the output value D of the synthesis unit 130 with the output value D of the level determination unit 150. An error value E, which is an error, is calculated. The error calculator 160 provides the calculated error value E to the feed forward filter 110, the feedback filter 120, and the trellis controller 170. At this time, the feed forward filter 110 and the feedback filter 120 update the filter tap coefficient based on the error value E provided from the error calculator 160.

The trellis control section 170 controls the operation of the trellis decoding section 140 based on the error value E provided from the error calculation section 160. That is, when the signal-to-noise ratio (SNR) corresponding to the error value E calculated by the error calculation unit 160 is equal to or larger than the set threshold, the trellis control unit 170 determines the overall decoding depth state of the trellis decoding unit 140. a plurality of decoding depth state 0, 1, 2, which is set to any out, ..., a plurality of decoded values outputted from the n _{d 0,} d 1, ..., feedback and _{d n} filter Control is performed so as to input to each of a plurality of corresponding 120 filter taps.

For example, as shown in FIG. 5, the trellis decoding unit 140 outputs a decoded value output from a plurality of set decoding depth states 0, 1, 2,..., N (Equation (7)). _{0, d} 1, ···, described the case of a _{d n.} A plurality of decoded _{values, d 0, d 1, ···} , are respectively input to corresponding filter tap of the feedback filter 120 corresponds to d _n traceback delay length. That is, the value d _0, which is decoded is output from the state of the decoding depth '0' is input to a first filter tap of the feedback filter 120, the decoded depth '1' decoded values d outputted from the state of ₁ is input to the (1 + K) th filter tap in K symbol units. Such a scheme value d _n decoded output from the state of the decoding depth 'n' in is input to a 1+ (n × K) th filter tap of the feedback filter 120.

The trellis decoding unit 140 according to the present invention performs trellis decoding on the input value Y, and the trellis decoding unit 140 is controlled by the trellis control unit 170 so that the trellis decoding unit 140 outputs from the plurality of decoding depth states set. number of decoded values _{d 0, d 1, ···,} and inputs the _{d n} to the appropriate respective filter taps of the feedback filter 120. Thus, the feedback filter 120, a plurality of decoded values inputted from the trellis decoder _{140 d 0, d 1, ···} , based on the _{d n,} to remove the post-ghost for each symbol.

Accordingly, the feedback filter 120 performs the filtering for removing the post ghost based on the determined level value fed back from the level determining unit 150, and performs a plurality of decoded values d ₀ , d _1, · · ·, is inputted to _{d n,} the feedback filter 120, a plurality of decoded values _{d 0,} d 1, · · ·, based on the _{d n,} a post-ghosts of each symbol removal Perform the following operation.

結果 As a result, it is possible to suppress an error propagation phenomenon of the feedback filter 120 due to an error in determining the level value in the level determination unit 150.

FIG. 6 is a table showing the signal-to-noise ratio of the output signal due to the output delay of trellis decoding. For reference, the broadcast signal used for the experiment is the Brazilian D channel.

As shown in FIG. 6, it can be seen that the Brazilian D channel has the largest signal-to-noise ratio when the decoding depth of the trellis decoding unit 140 is '0'. Therefore, it is preferable to input the value d ₀ trellis-decoded by the trellis decoding unit 140 to the feedback filter 120. As a result, even when a strong ghost is included in the previous part like the Brazilian D channel, the value d ₀ trellis-decoded by the trellis decoding unit 140 is input to the feedback filter 120, so that the equalization performance can be improved. Become like

FIG. 7 is a flowchart showing a preferred embodiment of a channel equalization method using a channel equalizer capable of improving the channel equalization performance according to the present invention. Note that the flowchart is based on FIGS. 4 and 5, and a detailed description thereof will be omitted.

First, the feed forward filter 110 removes (M) the influence of the pre-ghost on each symbol of the broadcast signal (S110). The feedback filter 120 removes (L) the effect of post ghost on each symbol of the broadcast signal (S120).

The combining unit 130 combines the value M from which the pre-ghost output from the feed forward filter 110 has been removed and the value L from which the post-ghost has been removed output from the feedback filter 120 (Y) (S130). . The trellis decoding unit 140 performs trellis decoding on the value Y synthesized by the synthesis unit 130 in tap units (S140).

The level determining unit 150 determines the value Y synthesized by the synthesizing unit 130 to be the closest signal level based on the set level (S150), and then determines the determined level value D by the feedback filter 120 and the error. It is provided to the calculation unit 160. The error calculation unit 160 compares the output value Y of the synthesis unit 130 with the output value D of the level determination unit 150 according to the set error update algorithm, and compares the output value D of the synthesis unit 130 with the output value D of the level determination unit 150. An error value, that is, an error value E is calculated (S160). The error calculator 160 provides the calculated error value E to the feed forward filter 110, the feedback filter 120, and the trellis controller 170. At this time, the feed forward filter 110 and the feedback filter 120 update the coefficient based on the error value E from the error calculator 160.

On the other hand, the trellis control section 170 controls the timing at which a plurality of decoded values trellis-decoded by the trellis decoding section 140 are input to the feedback filter 120 based on the error value E from the error calculation section 160 (S170). When the signal-to-noise ratio (SNR) corresponding to the error value E calculated by the error calculation unit 160 is equal to or larger than a set threshold, the trellis control unit 170 sets the plurality of decoded values trellis-decoded by the trellis decoding unit 140. Is input to the feedback filter 120 (S170).

Accordingly, the feedback filter 120 receives a plurality of decoded values from the trellis decoding unit 140 while performing filtering for removing a post ghost based on the determined level value fed back from the level determination unit 150. Then, the feedback filter 120 performs an operation of removing a post ghost of each symbol based on the plurality of decoded values.

結果 As a result, the equalization performance of the channel equalizer can be improved by suppressing the error propagation phenomenon that occurs in the feedback filter due to an error in the level determination unit.

The preferred embodiments of the present invention have been illustrated and described above. However, the present invention is not limited to the above-described specific preferred embodiments, and the gist of the present invention claimed in the claims is described. It is apparent that various modifications can be made by anyone having ordinary knowledge in the technical field to which the present invention pertains without departing from the scope of the invention, and that such modifications are within the scope of the claims. is there.

The present invention is applicable to a channel equalizer of a single carrier receiver for equalizing a received signal with respect to a channel environment using a plurality of decoded symbols provided from a trellis decoder and a channel equalizing method thereof.

FIG. 9 is a diagram illustrating an example of a channel equalizer applied to a conventional single carrier receiver. FIG. 11 is a diagram illustrating another example of a channel equalizer applied to a conventional single carrier receiver. FIG. 2 is a block diagram schematically illustrating a single carrier receiver according to the present invention. FIG. 2 is a block diagram showing a preferred embodiment of a channel equalizer capable of improving equalization performance according to the present invention. FIG. 5 is a conceptual diagram illustrating output of trellis decoded values of a trellis decoding unit in FIG. 4. 9 is a table showing a signal-to-noise ratio of an output signal according to an output delay of trellis decoding. 4 is a flowchart illustrating a channel equalization method for a single carrier receiver according to the present invention.

Explanation of reference numerals

Reference Signs List 81 demodulation unit 82 distortion compensation unit 83 comb filter 84 channel equalization unit 85 phase restoration unit 87 trellis decoding unit 88 deinterleaver 89 Reed-Solomon decoding unit 110 feed forward filter 120 feedback filter 130 synthesis unit 140 trellis decoding unit 150 level determination Unit 160 Error calculation unit 170 Trellis control unit

Claims (37)

A feed forward filter for removing a pre-ghost of each symbol from the input signal,
A feedback filter for removing a post ghost of each symbol from the input signal;
A combining unit that adds the symbol from which the pre-ghost has been removed and the symbol from which the post-ghost has been removed,
A level determination unit that determines the symbol added by the synthesis unit to a corresponding level value based on a set level, and feeds back the level value to the feedback filter;
A trellis decoding unit that performs trellis decoding on the symbols added by the combining unit,
An error calculating unit that calculates an error between the symbol added by the combining unit and the level value determined by the level determining unit by a set error update algorithm,
A trellis control unit that controls the trellis decoding unit to input a plurality of decoded symbols output from the trellis decoding unit to the feedback filter based on the error value calculated by the error calculation unit;
A channel equalizer for a single carrier receiver, comprising: The trellis control unit,
When the signal-to-noise ratio corresponding to the error value is equal to or larger than a set threshold, the trellis decoding unit is configured to input the plurality of decoded symbols output from the trellis decoding unit to the feedback filter. The channel equalizer of claim 1, wherein the channel equalizer is controlled. The trellis decoding unit,
2. The symbol according to claim 1, wherein the entire decoded depth is N (N is a natural number), and the symbol length of the entire trace back delay is N * K (K is a natural number). Single carrier receiver channel equalizer. The trellis decoding unit,
4. The channel of claim 3, wherein the plurality of decoded symbols output from a plurality of decoding depths of the entire decoding depth are input to the feedback filter. 5. Equalizer. A decoded symbol output from the state where the decoding depth of the trellis decoding unit is n (n is the equation (1)) is input to a 1+ (n × K) th filter tap of the feedback filter,
The single symbol according to claim 4, wherein the plurality of decoded symbols output from the plurality of decoding depths are input to corresponding filter taps of the feedback filter. Channel equalizer for carrier receiver.

The feedback filter is
When the level value determined by the level determination unit is input, the post ghost for each symbol is removed based on the level value,
2. The method according to claim 1, wherein when the plurality of decoded symbols are input from the trellis decoding unit, the post ghost is removed based on the plurality of decoded symbols. Channel equalizer for carrier receiver. Removing a pre-ghost of each symbol from the input signal with a feed forward filter;
Removing a post ghost of each symbol for the input signal with a feedback filter;
Adding the symbol from which the pre-ghost has been removed and the symbol from which the post-ghost has been removed;
A feedback step of determining the added symbol to a corresponding level value based on the set level, and inputting the level value to the feedback filter;
Calculating an error between the symbol added by the set error update algorithm and the determined level value;
A trellis decoding step of performing trellis decoding with a trellis decoder; and
Controlling whether to input a plurality of decoded symbols output from the trellis decoder to the feedback filter in accordance with the calculated error value. Machine channel equalization method. The control step includes:
The plurality of decoded symbols output from the trellis decoder are input to the feedback filter when a signal-to-noise ratio corresponding to the error value is equal to or greater than a set threshold. 8. The method for channel equalization of a single carrier receiver according to claim 7. The trellis decoder of the trellis decoding step,
8. The channel of a single carrier receiver according to claim 7, wherein the entire decoding depth is N (N is a natural number), and the symbol length of the entire traceback delay is N × K (K is a natural number). Method. The unit of claim 9, wherein the trellis decoder inputs the plurality of decoded symbols output from a plurality of decoding depths of the entire decoding depth to the feedback filter. Channel equalization method for one carrier receiver. A decoded symbol output from the state where the decoding depth of the trellis decoder is n (n is the equation (2)) is input to a 1+ (n × K) th filter tap of the feedback filter,
11. The unit according to claim 10, wherein the plurality of decoded symbols output from the plurality of decoding depths are input to respective corresponding filter taps of the feedback filter. Channel equalization method for carrier receiver.

The feedback filter is
Removing the post ghost for each symbol based on the level value;
The method according to claim 10, wherein, when the plurality of decoded symbols are input from the trellis decoder, the post ghost is removed based on the plurality of decoded symbols. Channel equalization method for carrier receiver. A restoration unit for restoring the original signal at the time of transfer from the input signal,
A phase restoration unit for restoring phase distortion of the input signal;
A channel equalizer that performs channel equalization using symbols decoded in trellis decoding depth units for the symbols of the input signal in which the phase distortion has been restored,
A deinterleaver that performs deinterleaving on the channel-equalized input signal and a Reed-Solomon decoding unit that performs Reed-Solomon decoding on the deinterleaved input signal,
A single carrier receiver comprising: The restoring unit includes:
A demodulation unit that converts the input signal to baseband,
For the baseband input signal, a segment synchronization signal, a field synchronization signal, and a distortion compensation unit that restores at least one of distortions to symbol timing,
A comb filter for removing an NTSC interference signal from the input signal from which the distortion has been restored;
14. The single carrier receiver according to claim 13, comprising: The channel equalizer includes:
A feed forward filter for removing a pre-ghost of each symbol from the input signal,
A feedback filter for removing a post ghost of each symbol from the input signal;
A combining unit that adds the symbol from which the pre-ghost has been removed and the symbol from which the post-ghost has been removed,
A level determination unit that determines the symbol added by the synthesis unit to a corresponding level value based on a set level, and feeds back the level value to the feedback filter;
A trellis decoding unit that performs trellis decoding on the symbols added by the combining unit,
An error calculating unit that calculates an error between the symbol added by the combining unit and the level value determined by the level determining unit by a set error update algorithm,
A trellis control unit that controls the trellis decoding unit to input a plurality of decoded symbols output from the trellis decoding unit to the feedback filter based on the error value calculated by the error calculation unit;
14. The single carrier receiver according to claim 13, comprising: The trellis decoding unit,
The single carrier receiver according to claim 15, wherein the entire decoding depth is N (N is a natural number), and the symbol length of the entire traceback delay is NxK (K is a natural number). The trellis decoding unit,
17. The single carrier receiver according to claim 16, wherein the plurality of decoded symbols output from a plurality of decoding depths of the entire decoding depth are input to the feedback filter. The trellis control unit,
When the signal-to-noise ratio corresponding to the error value is equal to or larger than a set threshold, the trellis decoding unit is configured to input the plurality of decoded symbols output from the trellis decoding unit to the feedback filter. 16. The single carrier receiver according to claim 15, wherein the receiver is controlled. A decoded symbol output from the state where the decoding depth of the trellis decoding unit is n (where n is equation (3)) is input to a 1+ (n × K) th filter tap of the feedback filter,
20. The method according to claim 18, wherein the plurality of decoded symbols output from the plurality of decoding depths are input to corresponding filter taps of the feedback filter. Carrier receiver.

The feedback filter, when the level value determined by the level determination unit is input, removes the post ghost for each symbol based on the level value, the trellis decoding unit to remove the plurality of decoded 16. The single carrier receiver according to claim 15, wherein when a symbol is input, the post ghost is removed based on the plurality of decoded symbols. A channel equalizer for removing pre-ghost and post-ghost of each symbol of the input signal; and
The sum of the symbols of the input signal from which the pre-ghost and the post-ghost have been removed and the sum of the symbols of the input signal from which the pre-ghost and the post-ghost have been removed based on predetermined level data are trellis. A trellis decoder for decoding;
A single carrier receiver comprising: The channel equalizer comprises:
22. The unit according to claim 21, further comprising: a feedback filter for removing a post ghost of each symbol of the input signal, and a feed forward filter for removing a pre ghost of each symbol of the input signal. One carrier receiver. The channel equalizer comprises:
22. The single carrier receiver according to claim 21, further comprising a level determination unit that determines a level of the symbol based on the predetermined level data and feeds back the determined level to the feedback filter. In the level determination unit,
24. The single carrier receiver according to claim 23, wherein a level of the symbol from which the pre-ghost and the post-ghost have been removed is determined based on the predetermined level data. The feedback filter is
24. The single carrier receiver according to claim 23, wherein the post ghost-removed symbol is output based on the determined level. The channel equalizer comprises:
24. The unit according to claim 23, further comprising: an error calculator that calculates an error value between the sum of symbols of the input signal from which the pre-ghost and the post-ghost have been removed and the predetermined level. One carrier receiver. The channel equalizer comprises:
The trellis decoder according to claim 26, further comprising: a trellis decoder that trellis-decodes a sum of symbols of the input signal from which the pre-ghost and the post-ghost have been removed based on the error value of the error calculator. Single carrier receiver. The channel equalizer comprises:
A controller for controlling the trellis decoder to transmit a decoded sum of the symbols of the input signal from which the pre-ghost and the post-ghost have been removed to the feedback filter. 28. The single carrier receiver of claim 27. The feedback filter is
29. The single carrier receiver of claim 28, wherein post ghosts of the symbols of the input signal are removed based on the decoded sum. The channel equalizer comprises:
22. The single carrier receiver according to claim 21, wherein the decoded sum of the symbols of the input signal from which the pre-ghost and the post-ghost are removed is transmitted to the feedback filter. 31. The single carrier receiver according to claim 30, wherein the channel equalizer generates a symbol from which the post ghost of the input signal has been removed based on the error value. The channel equalizer comprises:
The method of claim 30, wherein the post ghost-free symbols of the input signal are generated based on a decoded sum of the symbols of the input signal with the pre-ghost and the post-ghost removed. A single carrier receiver according to claim 1. The channel equalizer comprises:
Transmitting the decoded symbol of the input signal to the feedback filter such that the post ghost of the symbol of the input signal is removed based on the decoded sum in the feedback filter. A single carrier receiver according to claim 21. Removing pre-ghost and post-ghost of each symbol of the input signal; and summing the pre-ghost and post-ghost-free symbols of the input signal based on predetermined level data and the input. A decoding step of trellis decoding the sum of the symbols from which the pre-ghost and the post-ghost of the signal have been removed;
A channel equalization method for a single carrier receiver, comprising: The decoding step includes:
Determining the level of the sum based on the predetermined level data;
35. The method of claim 34, further comprising: feeding back the determined level to a feedback filter. Removing the post ghost of each symbol of the input signal comprises:
The method of claim 35, further comprising outputting a symbol from which the post ghost has been removed based on the determined level. The decoding step includes:
The sum of the decoded symbols of the input signal from which the pre-ghost and the post-ghost have been removed is calculated as the determined level and the symbol of the input signal from which the pre-ghost and the post-ghost have been removed. The method of claim 35, further comprising transmitting to the feedback filter based on an error value between the sums.

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