JP2006067438A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance precision of symbol synchronization of a receiving signal in a receiver which performs the symbol synchronization on the basis of the receiving signal. <P>SOLUTION: The receiver has a storage means for storing synchronous word patterns about a plurality of channel types including a channel type having preamble and a channel type without having the preamble and a storage means for storing a preamble pattern about the channel type having the preamble, correlation value maximum channel type detection means B1 to B4, C1 to C4, 7 detect channel types in which the maximum correlation value between synchronous word patterns and the receiving signals by every channel type becomes maximum, maximum correlation value position information detection means B5, C5, 8, 10 detect information regarding signal positions where the maximum correlation value between the preamble patterns and the receiving signals is acquired and symbol synchronization means 11, 12 perform the symbol synchronization by the information when the detected channel types have the preamble. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a receiver that receives a signal, and more particularly to a receiver that improves the accuracy of symbol synchronization of a received signal when performing timing synchronization using a known pattern of the received signal.

For example, in a digital wireless communication system such as a municipal digital broadcast communication system, a signal received by a receiver is divided into frames, and the frame is further divided into slots.
In such a wireless communication system, as an example, a frame configuration as shown in FIG. 3 is used, and a signal format of each slot as shown in FIGS. 4A to 4C is used. Symbol mapping as shown is used.
3 to 5 will be described in detail in an embodiment of the present invention described later.

The synchronization word for symbol synchronization and frame synchronization is one of seven patterns SW1 to SW7 depending on the channel type. When this is mapped on the IQ plane, the symbol is shown in FIG. 5, for example. It consists of only two diagonal points “0” and “A”.
In this way, when the symbol of the synchronization word is composed of only two diagonal points {0, A}, symbols in the same phase as the synchronization word (ie, “0” or “A”) are included in the symbols before and after the synchronization word. ), For example, the correlation peak position is more likely to be affected than when the synchronization word symbol is composed of the four outermost points {0, 2, 8, A}.

  One symbol of channel type (C) is arranged behind the synchronization word (SW) included in the slot of each physical channel shown in FIGS. This channel type symbol takes one of the values “0”, “2”, “8”, and “A” depending on the channel type. For example, in the case of a control channel, it takes “A” and is empty. Takes "0" for line or sync burst.

  Further, in the loudspeaker broadcasting, in the frame configuration shown in FIG. 3, the master station transmits a control channel in slot 0 and transmits a communication channel in slot 1, slot 2, slot 4 and slot 5. In the slave station, the channel type (C) behind the synchronization word used for synchronization is “A” when receiving this, particularly when receiving while synchronizing with the synchronization word of the control channel of slot 0. In this case, the phase of the correlation peak is affected by the channel type and an error occurs in the symbol timing, and the demodulation error rate characteristic is deteriorated.

  Further, in a digital wireless communication system such as a municipal digital broadcast communication system, since the roll-off rate is 0.2, the eye pattern opens poorly due to a slight error in symbol timing. Therefore, the bit error rate characteristic is greatly deteriorated due to an error in symbol timing.

JP 2003-115829 A JP 2002-101140 A JP 2002-101139 A JP 2002-111646 A ARIB STD-T86, “Municipal Digital Broadcasting System”, The Japan Radio Industry Association

As described above, in a digital wireless communication system such as a municipal digital broadcast communication system, when symbol synchronization or frame synchronization is performed by correlation calculation of a synchronization word, an error occurs due to symbols before and after the synchronization word, and bit error rate characteristics There was a problem that the deterioration.
In particular, in a system such as a municipal digital broadcast communication system (ARIB STD-T86) where the modulation method is 16QAM and the roll-off rate is as small as 0.2, the bit error rate characteristic is small due to a slight symbol synchronization error. Therefore, it is necessary to reduce errors in symbol synchronization and frame synchronization.
The present invention has been made to solve such a conventional problem, and an object thereof is to provide a receiver capable of improving the accuracy of symbol synchronization of a received signal.

To achieve the above object, the receiver according to the present invention performs symbol synchronization based on the received signal as follows.
That is, the synchronization word pattern storage means stores the synchronization word pattern for a plurality of channel types. Here, the plurality of channel types include a channel type having a preamble and a synchronization word in the signal, and a channel type having a synchronization word without having a preamble in the signal.
Preamble pattern storage means stores a preamble pattern for a channel type having a preamble and a synchronization word in the signal.
Correlation value maximum channel type detection means detects the channel type that maximizes the maximum correlation value between the sync word pattern and the received signal for each channel type stored in the synchronization word pattern storage means. For example, the maximum correlation value (maximum correlation value) between the synchronization word pattern and the received signal is detected for each channel type, and the channel type having the maximum maximum correlation value among a plurality of channel types is detected. .
The maximum correlation value position information detection means detects information relating to the signal position from which the maximum correlation value between the preamble pattern stored in the preamble pattern storage means and the received signal is acquired. For example, the maximum correlation value (maximum correlation value) between the preamble pattern and the received signal is acquired, and information on the signal position from which the maximum correlation value is acquired is detected.
If the channel type detected by the correlation value maximum channel type detection unit is a channel type having a preamble and a synchronization word in the signal, the symbol synchronization unit includes information detected by the maximum correlation value position information detection unit. Based on this, symbol synchronization is performed.
Therefore, when a signal of a channel type having a preamble and a synchronization word in the signal is received, symbol synchronization is performed using the preamble included in the received signal, thereby improving the accuracy of symbol synchronization of the received signal. it can.

Here, various signals may be used as the received signal.
Various preambles (patterns) may be used. For example, an AGC preamble or a fixed pattern can be used. For example, a predetermined symbol string (arrangement of a plurality of symbols) can be used. .
Further, as the preamble (pattern), for example, different patterns may be used for each channel type, or the same pattern may be used for two or more channel types.
Various sync words (patterns) may be used.
As the synchronization word (pattern), for example, different patterns are used for each channel type.
The means for storing the pattern can be configured using, for example, a memory for storing the pattern, a register for setting the pattern, or the like.

Further, one or more channel types are used as channel types having a preamble and a synchronization word in the signal.
Further, one or more channel types are used as channel types having a synchronization word without having a preamble in the signal.
The maximum correlation value between the sync word pattern and the received signal for each channel type is, for example, the maximum correlation value by shifting the signal position (timing) for calculating the correlation value between the sync word pattern and the received signal. It is obtained by determining the value (maximum correlation value). It is assumed that the signal of the channel type that maximizes the maximum correlation value is received.

The signal position (timing) at which the maximum correlation value between the preamble pattern and the received signal is acquired is, for example, the maximum by shifting the signal position (timing) for calculating the correlation value between the preamble pattern and the received signal. The correlation value (maximum correlation value) is determined, and the signal position (timing) from which the maximum correlation value is obtained can be detected.
Also, as information regarding the signal position (timing) from which the maximum correlation value between the preamble pattern and the received signal is acquired, various types of information may be used, and information capable of symbol synchronization is used.

The receiver according to the present invention has the following configuration as one configuration example.
As a channel type having a preamble and a synchronization word in the signal, one or both of a control channel and a synchronization burst channel are used.
A channel for communication is used as a channel type having a synchronization word without having a preamble in the signal.
The maximum correlation value position information detecting means detects information relating to a difference between a signal position at which a maximum correlation value between a preamble pattern stored in the preamble pattern storage means and a received signal is acquired and a predetermined reference position.
The symbol synchronization means performs symbol synchronization by controlling a clock so as to compensate for the difference based on information on the difference detected by the maximum correlation value position information detection means.
Therefore, symbol synchronization of the received signal can be performed by controlling the clock so as to compensate for the difference between the signal position where the maximum correlation value between the preamble pattern and the received signal is acquired and the predetermined reference position.

Here, various channels may be used as the control channel.
Various channels may be used as the synchronization burst channel.
Various channels may be used as communication channels.
In addition, as a predetermined reference position (reference timing) regarding the signal position (timing) from which the maximum correlation value between the preamble pattern and the received signal is acquired, for example, the maximum correlation value between the preamble pattern and the received signal is acquired. The ideal signal position (timing) to be used is used.
Various information may be used as the information regarding the difference from the predetermined reference position (reference timing). For example, the fluctuation (difference) due to noise is removed by averaging by a random walk filter function or the like. Also good.
Further, as a mode for controlling so as to compensate for the difference regarding the signal position (timing), for example, a mode for controlling the difference to be zero (0) is used.
Further, as a mode for controlling the clock, for example, a mode for controlling the cycle (speed) of the clock can be used.

  As described above, according to the receiver according to the present invention, each of a plurality of channel types including a channel type having a preamble and a synchronization word in the signal and a channel type having a synchronization word without having a preamble in the signal. The synchronization word pattern is stored, the preamble pattern is stored for the channel type having the preamble and the synchronization word in the signal, and the maximum correlation value between the synchronization word pattern for each channel type and the received signal is maximized. Detects the channel type and, if the detected channel type is a channel type having a preamble and a synchronization word in the signal, detects information on the signal position from which the maximum correlation value between the preamble pattern and the received signal is acquired. Symbol synchronization based on the result of It is possible to improve the symbol synchronization accuracy Shin signal.

Embodiments according to the present invention will be described with reference to the drawings.
First, with reference to FIG. 3 to FIG. 5, a communication method used in a municipal digital broadcast communication system (ARIB STD-T86) which is a digital wireless communication system according to the present embodiment will be described.
In this example, the direction of communication from the control station device or base station device, which is the upper master station, to the individual receiver or mobile receiver, etc., which is the lower slave station receiver, is set to the down direction. The direction of communication from the station to the upper master station is assumed to be upstream.

In the municipal digital broadcast communication system of this example, the signal received by the receiver is divided into frames, and the frame is further divided into slots.
FIG. 3 shows a configuration example of a frame used in the municipal digital broadcast communication system (ARIB STD-T86) of this example.
In the frame configuration of this example, the period of one frame is 80 ms, and one frame is equally divided into six slots. The numbers of the slots in the frame are slot 0, slot 1, and slot in order from the top of the frame. 2, slot 3, slot 4, and slot 5. In this example, as in the normal case, the control physical channel (CCH) is assigned to slot 0 and slot 3, and the communication physical channel (TCH) is assigned to slot 1, slot 2, slot 4, and slot 5. Assigned.

The control physical channel (CCH) is used for communication control. Basically, slot 0 is downlink and slot 3 is uplink.
The communication physical channel (TCH) transmits voice, FAX, data for data communication, and the like. In addition, when performing a loud sound broadcast, slot 1, slot 2, slot 4, and slot 5 are used as downlinks. When a communication call is performed, basically, slot 1 and slot 2 are used as downlink, and slot 4 and slot 5 are used as uplink.
In addition, a high-speed associated control channel (FACCH) may be assigned to the communication physical channel (TCH), and when a high-speed associated control channel (FACCH) is assigned, it is used for communication control.

4A to 4C show an example of the signal format of each slot.
FIG. 4 (a) shows an example of the signal format of the slot of the control physical channel.
The slots of the control physical channel are, in order from the top, a 4-symbol burst transient response ramp time part (R), a 6-symbol AGC preamble (AP), a 1-symbol pilot symbol (P), and a 58-symbol AGC preamble (AP), 10 symbol synchronization word (SW), 1 symbol channel type (C), 58 symbol control signal (CAC), 1 symbol pilot symbol (P), 6 symbol A control signal (CAC) and a guard time part (G) of 5 symbols are included.

FIG. 4B shows an example of the signal format of the slot of the communication physical channel.
The slots of the communication physical channel are, in order from the head, a 4-symbol burst transient response ramp time (R), a 6-symbol traffic channel (TCH) or a fast associated control channel (FACCH), and a 1-symbol pilot symbol. (P), 58 symbol traffic channel (TCH) or high speed associated control channel (FACCH), 10 symbol synchronization word (SW), 1 symbol channel type (C), 58 symbol traffic channel (TCH) ) Or fast associated control channel (FACCH), 1 symbol pilot symbol (P), 6 symbol traffic channel (TCH) or fast associated control channel (FACCH), and 5 symbol guard time part (G) It consists of

FIG. 4 (c) shows an example of the signal format of the slot of the synchronization burst.
The synchronous burst slots are, in order from the top, a 4-symbol burst transient response ramp time (R), a 6-symbol fixed pattern (FP), a 1-symbol pilot symbol (P), and a 58-symbol fixed pattern. (FP), 10-symbol synchronization word (SW), 1-symbol channel type (C), 58-symbol parameter part (PP), 1-symbol pilot symbol (P), and 6-symbol parameter part (PP) and a guard time part (G) of 5 symbols.

FIG. 5 shows an example of 16QAM (16 Quadrature Amplitude Modulation) symbol mapping used in this example on the IQ plane.
As shown in FIG. 5, the symbol mapping of this example uses symbols “0” to “F” using hexadecimal numbers.

Here, the AGC preamble (AP) included in the slot of the control physical channel shown in FIG. 4A and the fixed pattern (FP) included in the slot of the synchronization burst shown in FIG. Also, in the symbol mapping shown in FIG. 5, it is a repeating pattern of “20A800080A”, and in this example, these are called preambles.
Moreover, as a control signal contained in the slot of the control physical channel shown in FIG. 4A, for example, a broadcast channel (BCCH), a general call channel (PCH), or a dedicated cell channel (SCCH) is used. It is done.
As the pilot symbol (P), “A” is used in the symbol mapping shown in FIG.

In the receiver, symbol synchronization is performed in order to demodulate the bit string from the modulated received signal. Further, in order to extract information elements such as a control signal (CAC), a traffic channel (TCH), a high-speed associated control channel (FACCH), and a parameter part (PP) from the demodulated signal, the receiver Frame synchronization is performed so that it is possible to grasp the bit number of the information element.
In this example, the slot of each physical channel shown in FIGS. 4A to 4C is commonly provided with a synchronization word (SW) at the center of the slot, and the receiver receives this synchronization word. Is used to perform symbol synchronization and frame synchronization.

In this example, as a general technique for performing symbol synchronization or frame synchronization using a synchronization word, a method is used in which a correlation operation between a received signal and a synchronization word symbol pattern is performed and synchronization is performed based on the peak position.
In this example, in the symbol mapping shown in FIG. 5, “000A0A00A0” is used as the synchronization word SW1 of the downlink control physical channel (other than the head of the superframe), and “synchronization word SW2 of the uplink control physical channel is“ 000A0AA00A ”is used,“ 00A000AAAA ”is used as the synchronization word SW3 of the downlink communication physical channel,“ 00A000000A ”is used as the synchronization word SW4 of the uplink communication physical channel, and the downlink control physical “00A0AAAAA0” is used as the synchronization word SW5 of the channel (the head of the superframe), “0000AA0A0A” is used as the synchronization word SW6 of the downlink synchronization burst, and the synchronization word SW7 of the uplink synchronization burst "0000AAA0AA" Te have been used.
Thus, the sync word is one of seven types of patterns SW1 to SW7 depending on the channel type.

A receiver according to a first embodiment of the present invention will be described.
FIG. 1 shows a configuration example of a slave station receiver of the municipal digital broadcast communication system of this example.
The slave station receiver of this example includes an input terminal A, a radio frequency (RF) unit circuit 1, an A / D (Analog to Digital) converter 2, an orthogonal detection unit 3, a reception filter 4, and a demodulation processing unit. 5, accumulation buffer 6, five correlators B1 to B5, five maximum value search units C1 to C5, maximum value selection unit 7, subtractor 8, switch 9, and random walk filter unit 10, a frame control unit 11, and a clock generation unit 12.

This example shows a case where the present invention is applied to synchronization tracking after the initial synchronization acquisition is completed. In the following description of the operation example, it is assumed that the initial synchronization acquisition is completed.
An antenna (not shown) is connected to the input terminal A, and a received signal is input to the high frequency circuit 1.
The high frequency unit circuit 1 amplifies the signal input from the antenna by, for example, an amplifier, converts the frequency of the input signal from a frequency in the radio band to an intermediate frequency that can be sampled by the A / D converter 2, and converts the frequency The subsequent signal is output to the quadrature detection unit 3.

The A / D converter 2 samples and quantizes the signal input from the high frequency unit circuit 1, converts the signal from analog to digital, and outputs the signal to the quadrature detection unit 3.
The quadrature detection unit 3 extracts the in-phase component (I component) and the quadrature component (Q component) of the baseband signal from the reception signal input from the A / D converter 3 and outputs them to the reception filter 4.
In FIG. 1, the output signal from the quadrature detection unit 3 is output with two signal lines as an I component and a Q component, but is represented by a single line for the sake of simplicity.

The reception filter 4 performs processing of removing unnecessary frequency components and waveform shaping on the signal input from the quadrature detection unit 3, and outputs the processed signal to the demodulation processing unit 5 and the accumulation buffer 6.
The demodulation processing unit 5 performs code determination of the signal input from the reception filter 4 and extracts bit data.
The accumulation buffer 6 accumulates at least a signal for timing synchronization with respect to the signal input from the reception filter 4, and a necessary portion (synchronization word or preamble) of the accumulated signal is stored in each correlator B1. Output to ~ B5.

In the correlators B1 to B5, the maximum value search units C1 to C5, the maximum value selection unit 7, the subtractor 8, the switch 9, the random walk filter unit 10, and the frame control unit 11, which are described below, are stored in the storage buffer 6. Since the received signal is used, processing is performed once in 13.33 ms (= 80 ms / 6), which is a time corresponding to one slot.
In the downstream signal transmitted from the master station, the synchronization word type is the synchronization word SW1 of the control physical channel (other than the head of the superframe), the synchronization word SW5 of the control physical channel (the head of the superframe), and the synchronization burst synchronization. Since there are four types of word SW 6 and communication physical channel synchronization word SW 3, correlators B 1, B 2, B 3, and B 4 that perform correlation operations with these four types of synchronization word patterns are provided.
Further, in this example, a correlator B5 that performs correlation calculation with a preamble pattern that is an AGC preamble (AP) or a fixed pattern (FP) is provided.

The correlator B1 performs a correlation operation between the signal accumulated in the accumulation buffer 6 and the synchronization word (pattern) SW1, and outputs the result to the maximum value search unit C1.
Similarly, the correlator B2 performs a correlation operation between the signal accumulated in the accumulation buffer 6 and the synchronization word (pattern) SW5, and outputs the result to the maximum value search unit C2.
Similarly, the correlator B3 performs a correlation operation between the signal stored in the storage buffer 6 and the synchronization word (pattern) SW6, and outputs the result to the maximum value search unit C3.
Similarly, the correlator B4 performs a correlation operation between the signal stored in the storage buffer 6 and the synchronization word (pattern) SW3, and outputs the result to the maximum value search unit C4.

The correlator B5 performs a correlation operation between the signal accumulated in the accumulation buffer 6 and the preamble pattern, and outputs the result to the maximum value search unit C5.
In this example, as the correlation calculation in the correlator B5, the correlation calculation is performed with the preamble pattern of the central part of the preamble portion at the 5th to 69th symbols from the beginning of the slot. Reduce the effects of symbols. As the central portion of the preamble portion, for example, 10 symbols of the 32nd to 41st symbols from the beginning of the slot are used.
Note that the patterns of the synchronization words SW1, SW5, SW6, and SW3 used in the correlators B1 to B4 and the preamble pattern used in the correlator B5 are set.

Each maximum value search unit C1 to C4 for the synchronization word searches for the maximum value of the correlation calculation result input from each correlator B1 to B4 and outputs it to the maximum value selection unit 7.
The maximum value search unit C5 searches the maximum value of the correlation calculation result input from the correlator B5, and obtains a number (maximum value number) indicating the position of the searched maximum value (for example, the position in the slot). Output to the subtracter 8.
The subtracter 8 subtracts the reference value n from the maximum value number input from the maximum value search unit C5 and outputs the subtraction result (timing error value) to the terminal b of the switch 9.
Here, the reference value n is a number representing the reference position of the preamble in the slot (or in the frame). That is, the output value from the subtracter 8 becomes the timing error value of the received signal due to the preamble correlation.

  The maximum value selection unit 7 compares the maximum correlation value for each synchronization word pattern input from each maximum value search unit C1 to C4, and determines the maximum correlation value (ie, superframe) from any of the correlators B1 to B3. If the synchronization word SW1 of the control physical channel other than the head, the synchronization word SW5 of the control physical channel at the head of the superframe, or the synchronization word SW6 of the synchronization burst) is the maximum, the switch 9 Control is performed so that the terminal b and the terminal c are connected, and in other cases, the terminal a and the terminal c of the switch 9 are connected.

The value “0” is input to the terminal a of the switch 9.
The switch 9 selects the value “0” input to the terminal a or the timing error value input to the terminal b from the subtractor 8 according to the switch switching state controlled by the maximum value selection unit 7, from the terminal c. Output to the random walk filter unit 10.
Then, if any sync word of the control channel or sync burst sync word type (synchronization word SW1, SW5, SW6), which is a frame type having a preamble, is detected in the random walk filter unit 10, the preamble is detected. A timing error value due to correlation is input, and when a synchronization word SW3 of a communication physical channel that is a frame type having no preamble is detected, a value “0” is input.
The processing in the random walk filter unit 10 and the frame control unit 11 in the subsequent stage operates only when the terminal b and the terminal c of the switch 9 are connected.

FIG. 2 shows a configuration example of the random walk filter unit 10.
The random walk filter unit 10 of this example includes a determiner 21, an integrator 22, and a determiner 23 between the input terminal D1 and the output terminal D2.
The input terminal D1 of the random walk filter unit 10 of this example is connected to the terminal c of the switch 9, and the output terminal D2 is connected to the input terminal of the frame control unit 11.

In the random walk filter unit 10, the timing error value from the terminal c of the switch 9 is input to the determiner 21 via the input terminal D1.
The determiner 21 outputs a predetermined value to the integrator 22 according to the sign of the input timing error value. Specifically, the determiner 21 outputs a value of “−1” to the integrator 22 when the input timing error value is negative (that is, when the timing error value <0), and When the input timing error value is zero (that is, when the timing error value = 0), a value of “0” is output to the integrator 22, and the input timing error value is positive. In some cases (that is, when the timing error value> 0), a value of “+1” is output to the integrator 22.

The accumulator 22 has a register therein, and the initial value of the internal register is zero.
Then, the integrator 22 outputs the sum value s of the value input from the determiner 21 and the value of the internal register to the determiner 23, and stores this sum value s in the internal register.
Further, the integrator 22 resets the value of the internal register to 0 when it is controlled to reset from the determiner 23.

The determination unit 23 has a comparison value W (positive integer) set therein, compares the absolute value | s | of the value s input from the integrator 22 with the comparison value W, and calculates the absolute value | s | Is equal to or greater than the comparison value W (ie, | s | ≧ W), the value of the internal register of the accumulator 22 is controlled to be reset to 0. At this time, the value s input from the accumulator 22 is controlled. Is equal to or greater than W (ie, s ≧ W), the value “+1” is output to the frame controller 11 via the output terminal D2, and the value s input from the integrator 22 is −W or less (ie, s ≦ −W), the value “−1” is output to the frame controller 11 via the output terminal D2.
Further, when the absolute value | s | of the value s input from the integrator 22 is smaller than the comparison value W (that is, when | s | <W), the determiner 23 sets the value “0”. The data is output to the frame control unit 11 via the output terminal D2.
In this way, since the random walk filter unit 10 internally accumulates the sign of the input value, if the peak position of the correlation related to the preamble fluctuates randomly due to noise, the fluctuation is absorbed and only the timing shift is detected. Can be detected.

When a positive value is input from the random walk filter unit 10, the frame control unit 11 outputs a signal (SBW signal) for increasing the clock cycle to the clock generation unit 12, and the random walk filter unit 10 outputs a negative value. When the value is input, a signal for shortening the clock cycle (SFW signal) is output to the clock generation unit 12.
The clock generation unit 12 generates and supplies a clock signal for receiver operation.
When the SBW signal is input from the frame control unit 11, the clock generation unit 12 delays the clock signal by increasing the clock period only immediately after that.
Further, when the SFW signal is input from the frame control unit 11, the clock generation unit 12 shortens the clock cycle only immediately after that to advance the clock signal.

Here, when the received signal is delayed with respect to the clock, since the correlation peak appears backward, the timing error value input to the random walk filter unit 10 is a positive value, and control is performed to delay the clock. Then, control is performed until the timing error value approaches zero.
On the other hand, when the received signal is advanced with respect to the clock, the correlation peak appears forward, so that the timing error value input to the random walk filter unit 10 is a negative value and is controlled to advance the clock. Thus, control is performed until the timing error value approaches zero.
In this way, the clock timing is controlled so that the timing error value always approaches 0, and symbol synchronization is performed.

In this example, when the correlation of the synchronization word SW1, SW5, SW6 of the control channel or synchronization burst that is the channel type having the preamble is detected to be higher than the correlation of the synchronization word SW3 of the communication channel, symbol synchronization is performed by the preamble correlation. Done.
For example, in a received signal during loudspeaker broadcasting, a control channel is received in slot 0 once per frame, and symbol synchronization based on preamble correlation is performed in slot 0. In this preamble correlation, since the signal at the center of the preamble part signal is used, the influence of the preceding and following symbols is small, so that the symbol synchronization error is reduced and the bit error rate characteristic deterioration is reduced.

As described above, in the receiver (digital receiver) of this example, when a synchronization type word pattern of a channel type having a preamble is detected from the received signal, the correlation calculation between the received signal and the preamble pattern is performed, Symbol synchronization is performed based on the peak position.
Further, in the receiver of this example, the correlation calculation between the received signal and a plurality of synchronization word patterns is performed, the synchronization word pattern having the highest correlation is selected, and the synchronization of the channel type in which the selected synchronization word pattern has a preamble is selected. In the case of a word pattern, correlation calculation between the received signal and the preamble pattern is performed, and symbol synchronization is performed based on the peak position.
In the receiver of this example, when the detected sync word type is a sync word type of a channel type having a preamble (in this example, a control channel or a sync burst), a continuous section in the middle of the preamble section The signal is correlated with the preamble pattern, and symbol synchronization is performed based on the peak position.

  Therefore, in the receiver of this example, the signal of the continuous symbol interval at the center of the preamble interval is used for the correlation calculation of symbol synchronization, and the symbols before and after the same are also continuous signal patterns of the same preamble. Errors in position are less likely to occur, and errors in symbol synchronization are less likely to occur. Thereby, timing errors can be reduced and reception performance can be improved.

  In the receiver of this example, the synchronization word pattern storage means is configured by the function of storing the synchronization word pattern of each channel, and a common preamble pattern (in this example, an AGC preamble and a fixed pattern pattern). Preamble pattern storage means is configured by the function of storing the correlation value, and the correlation value maximum channel type detection means is configured by the functions of the correlators B1 to B4, the maximum value search units C1 to C4 and the maximum value selection unit 7 related to the synchronization word The maximum correlation value position information detection means is configured by the functions of the correlator B5, the maximum value search unit C5, and the subtractor 8 (and the random walk filter unit 10 in this example) regarding the preamble, and the frame control unit 11 and the function of the clock generator 12 constitute a symbol synchronization means.

A receiving apparatus according to the second embodiment of the present invention will be described.
The receiving apparatus of this example has the function of a receiver as shown in the first embodiment.
The receiving device of this example is used as a device on the slave station side, receives a signal transmitted by radio from the device on the master station side by an antenna, and the received signal is shown in FIG. 1 and FIG. Processing is performed by such a receiver configuration to perform symbol synchronization and frame synchronization.
As described above, in the receiving apparatus of this example, the timing error can be reduced and the receiving performance can be improved by performing the timing synchronization using the symbol synchronization function as shown in the first embodiment. Can do.
In this example, the receiver having the function of the receiver as shown in the first embodiment is shown. However, for example, a communication apparatus having the function of the receiver and the function of the transmitter. (Transceiver) can also be implemented.

A disaster prevention radio system according to a third embodiment of the present invention will be described.
The disaster prevention administrative radio system of this example includes the receiving device or the communication device as shown in the second embodiment as a device on the slave station side.
The receiving device or communication device of this example is used as a device on the slave station side, receives a signal transmitted by radio from the device on the master station side by an antenna, and receives the received signal as shown in FIGS. Symbol synchronization and frame synchronization are performed by the receiver configuration as shown in FIG.
Thus, in the disaster prevention administrative radio system of this example, the timing error is reduced by performing the timing synchronization using the symbol synchronization function as shown in the first embodiment in the receiving device or the communication device. And reception performance can be improved.

Here, the configurations of the receiver, the reception device, the communication device, the wireless communication system, and the like according to the present invention are not necessarily limited to those described above, and various configurations may be used. The present invention can also be provided as, for example, a method or method for executing the processing according to the present invention, a program for realizing such a method or method, or a recording medium for recording the program. It is also possible to provide various devices and systems.
The application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.
In addition, as various processes performed in the receiver, the receiving apparatus, the communication apparatus, the wireless communication system, and the like according to the present invention, for example, the processor stores a ROM (Read Only Memory) in hardware resources including a processor, a memory, and the like. A configuration controlled by executing the control program may be used, and for example, each functional unit for executing the processing may be configured as an independent hardware circuit.
The present invention can also be understood as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disc) -ROM storing the control program, and the program (itself). The processing according to the present invention can be performed by inputting the program from the recording medium to the computer and causing the processor to execute the program.

It is a figure which shows the structural example of the subunit | mobile_unit receiver which concerns on 1st Example of this invention. It is a figure which shows the structural example of a random walk filter part. It is a figure which shows an example of the frame structure of a municipal digital broadcast communication system. It is a figure which shows an example of the signal format of each slot. It is a figure which shows an example of the symbol mapping of 16QAM in an IQ plane.

Explanation of symbols

  1 ·· High-frequency unit circuit, 2 ·· A / D converter, 3 ·· Orthogonal detection unit, 4 ·· Reception filter, 5 ·· Demodulation processing unit, 6 ·· Storage buffer, 7 ·· Maximum value selection unit, 8 .... subtractor, 9 .... switch, 10 .... random walk filter, 11 .... frame controller, 12 .... clock generator, A ... input terminal, B1-B5 ... correlator, C1-C5 ..Maximum value search section,

Claims (2)

In a receiver that performs symbol synchronization based on a received signal,
A synchronization word pattern storage means for storing a synchronization word pattern for a plurality of channel types including a channel type having a preamble and a synchronization word in the signal and a channel type having a synchronization word without having a preamble in the signal;
Preamble pattern storage means for storing a preamble pattern for a channel type having a preamble and a synchronization word in the signal;
Correlation value maximum channel type detection means for detecting a channel type that maximizes the maximum correlation value between the synchronization word pattern and the received signal for each channel type stored in the synchronization word pattern storage means;
Maximum correlation value position information detecting means for detecting information on a signal position from which a maximum correlation value between a preamble pattern stored in the preamble pattern storage means and a received signal is acquired;
When the channel type detected by the correlation value maximum channel type detection unit is a channel type having a preamble and a synchronization word in the signal, symbol synchronization is performed based on the information detected by the maximum correlation value position information detection unit. Symbol synchronization means to perform;
A receiver comprising: The receiver of claim 1,
As a channel type having a preamble and a synchronization word in the signal, one or both of a control channel and a synchronization burst channel are used,
As a channel type having a synchronization word without having a preamble in the signal, a communication channel is used,
The maximum correlation value position information detecting means detects information relating to a difference between a predetermined reference position and a signal position from which a maximum correlation value between a preamble pattern stored in the preamble pattern storage means and a received signal is acquired;
The symbol synchronization means performs symbol synchronization by controlling a clock so as to compensate for the difference based on information on the difference detected by the maximum correlation value position information detection means.
A receiver characterized by that.

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