JP2845802B2 - Synchronous detection and synchronous timing control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a synchronization detection and synchronization timing control method, and more particularly to a synchronization detection and synchronization timing control method for a digital MCA mobile radio.

[0002]

2. Description of the Related Art Generally, in a digital communication system in a wired system or a fixed wired communication system, the quality of a communication line is relatively stable. Synchronization can be said to be easy. However, in a digital MCA mobile radio using a digital mobile communication system, since stable communication line quality is not always ensured, multipath, fading, delay dispersion, and the like are required for synchronization detection and synchronization timing control. When a sudden change in the received signal occurs due to such factors, it may be difficult to establish synchronization.

MOD of conventional digital MCA mobile radio
A method for detecting synchronization and controlling synchronization timing by the EM unit will be described with reference to the drawings.

FIG. 3 is a flowchart showing a conventional synchronization detection and synchronization timing control method.

[0005] In FIG. 3, in the conventional synchronization detection, the reception signal data of the reception channel is transmitted from a radio section to a MODEM.
(S41), performs baseband conversion on the received received signal data sequence (S42), and detects a synchronization symbol, which is known information contained in the reception signal data sequence, in advance. The correlation value calculation is performed on the nearby received signal data sequence while shifting the correlation calculation window (correlation value calculation target range) in symbol data sampling units (S43, S44, S45), and the preset threshold value is set. A point where the maximum correlation value is exceeded is detected as a synchronization symbol position (S46), and frame synchronization is performed by regarding this detection point as a reception timing position.

The synchronous timing control operation includes:
The symbol of the received signal obtained when detecting the reception timing position and the amount of movement of the correlation calculation window in the sampling unit, that is, the amount of displacement of the window moved until the maximum correlation value is actually detected is the correction amount. (S47, S48),
Using this, an operation of correcting the next reception position is performed (S49). If a maximum correlation value exceeding a preset threshold value cannot be detected (S47), a synchronization detection operation is performed at a reception timing position obtained during the synchronization timing control immediately before for a certain fixed period, and synchronization is performed until synchronization can be detected again. The symbol detecting operation is repeated (S50). If the synchronization cannot be further detected, the AFC control operation and the search for the reception channel are performed again.
Normally, the reception position is driven up to the symbol unit level by AGC control or AFC control.
After that, the processing of the MODEM unit is performed, so that the detection of the synchronization symbol and the reception timing point thereof can be almost specified, and the correction may be performed in units of the symbol and the sampling timing.

[0007]

SUMMARY OF THE INVENTION This conventional digital M
The synchronization detection and synchronization timing control method of the CA mobile radio device is such that when a sudden change of a received signal occurs due to factors such as fading, multipath, and delay dispersion, a change in a synchronization symbol detection position frequently occurs. There is a problem that the reception timing position is frequently corrected. Also, when the synchronization symbol is determined by performing the correlation value calculation, in the above-described situation, a malfunction occurs in which a correlation value for a different symbol having characteristics similar to the actual synchronization symbol is regarded as valid. As a result, there is a problem that a position different from the original position is regarded as the reception timing position.

That is, in a situation where a received signal suddenly fluctuates due to factors such as multipath, fading, and delay dispersion, a correlation value calculation for a synchronization symbol and a maximum correlation value exceeding a preset threshold are shown. The conventional synchronous timing control method using the symbol obtained from the symbol point and the reception timing correction amount in the sampling unit cannot prevent the fluctuation of the reception timing position and the malfunction of the synchronous timing control due to the erroneous detection of the synchronous symbol. There is a point.

[0009]

A synchronization detection and synchronization timing control method according to the present invention is a synchronization detection and synchronization timing control method for a digital MCA mobile radio having a MODEM unit. As a method of setting a symbol unit used for the control of the timing control and a correction amount of the sampling timing unit, first, all the correlation values obtained at the time of the synchronization detection operation are integrated, and the integration result is referred to as “synchronization detection (synchronization establishment)” according to the magnitude. , "And" Synchronization not detected (synchronization not established) "
In the case of the "synchronization detection (synchronization establishment)", the correlation value integration result of the first half and the correlation value integration result of the second half are compared, and if there is a difference between them, the symbol unit and its sampling timing unit It is output by switching the correction amount.

[0010] The synchronization detection and synchronization timing control method of the present invention is a synchronization detection and synchronization timing control method for a digital MCA mobile radio having a MODEM unit. A correlation value is calculated for the data near the symbol, all the results are integrated, and “synchronization detection (synchronization establishment)” and “synchronization non-detection (synchronization non-establishment) are determined based on the magnitude of the integration result. Detection (establishment of synchronization) "
In the case of (2), as a synchronization timing control operation, the correlation value integration result of the first half and the correlation value integration result of the second half are compared, and if there is a difference between them, the sampling unit of the synchronization symbol data “±” correction amount of 1/8 the sampling timing unit "and as its controlled variable, if there is no difference to output the control amount as zero.

The synchronization detection and synchronization timing control method according to the present invention is the synchronization detection and synchronization timing control method for a digital MAC mobile radio having a MODEM unit, wherein the MODEM unit takes in the synchronization detection operation from the radio unit at the time of reception. In order to perform baseband conversion of the digital received data sequence and detect a synchronization symbol, which is known information contained in advance, first, data near the received synchronization symbol is correlated in symbol data sampling units. The correlation value is sequentially calculated while shifting the calculation window (correlation value calculation target range), the obtained correlation values are integrated, and the result of integrating all the correlation values near the synchronization symbol is a predetermined threshold value. Is exceeded, it is regarded as “synchronization detected (synchronization established)”. )), Frame synchronization is achieved, and as the synchronization timing control operation, in the case of “synchronization detection (synchronization establishment)”, all the correlation value integration results are compared with the correlation value integration results up to the first half. The correlation value integration results of the latter half are divided and compared, and if the correlation value integration results up to the first half are larger, the “+ ／ sampling unit” of the symbol data is replaced with the correlation value of the latter half. If the integration result is larger,
The sampling unit "is the synchronization timing correction amount to be obtained, and if there is no difference between the correlation value integration result of the first half and the correlation value integration result of the second half, the synchronization timing correction amount to be calculated is zero, and the correction amount performs an operation of correcting the next of the received position using.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a digital MCA mobile radio apparatus according to an application example of an embodiment of the present invention, and FIG. 2 is a synchronization detection and synchronization timing control method according to the embodiment in the application example shown in FIG. It is a flowchart which shows.

In FIG. 1, the digital MCA of this application example
The mobile radio includes a radio unit 2 for transmitting and receiving an encoded digital signal via an antenna 1, a digital modulation / demodulation process for modulating digital signal data to be transmitted and demodulating a received digital signal, and a synchronization symbol. A MODEM unit 3 that performs a correlation value calculation to detect a synchronization symbol position to detect a synchronization symbol position to perform frame synchronization, and a synchronization timing control process to control transmission timing and reception timing based on the detected synchronization symbol position. An encoding unit for encoding digital signal data other than the digital audio data to be transmitted, a decoding unit for decoding digital signal data other than the received digital audio data, and a control unit for controlling the operation timing of the audio codec; And a digital audio signal to be transmitted. An audio codec unit 5 comprising an encoding unit for decoding and converting the received digital audio data to digital audio data, and a decoding unit for decoding the received digital audio data and converting it to a digital audio signal; and a microphone (transmitter) 9 A PCM codec unit 6 comprising: a unit for converting an analog audio signal from the digital audio signal into a digital audio signal; and a unit for converting the digital audio signal into an analog audio signal to be output to a speaker (receiver) 8. An amplifier 7 for amplifying an analog audio signal supplied from the PCM codec unit 6 and supplying an output thereof to a speaker 8; an amplifier 10 for amplifying an analog audio signal output from the microphone 9 and supplying the amplified analog audio signal to the PCM codec unit 6; An MCPU (central control unit) 11 for controlling the operations of the above-described units, and an operation key An operation unit 12 which work is indicated, and a display unit 13 on which various operation states of MCPU 11 is displayed.

The MODEM unit 3 and the channel codec unit 4 each include a digital signal processor (D
SP) is controlled by software.
Further, the MCPU unit 11 is implemented by software using a general-purpose CPU chip.

Next, a method for detecting synchronization and controlling synchronization timing according to the present embodiment will be described with reference to FIGS.

The MODEM unit 3 in FIG. 1 performs a baseband conversion of the digital reception data sequence fetched from the radio unit 2 at the time of reception (S21, S22) as a synchronization detection operation, and uses the known information previously contained therein. In order to detect a certain synchronization symbol, first, correlation value calculation is sequentially performed on the data near the received synchronization symbol while shifting the correlation calculation window (correlation value calculation target range) in symbol data sampling units (S23). , S24), and the obtained correlation values are integrated (S25). When the result of integrating all the correlation values near the synchronization symbol exceeds a preset threshold (S26), "synchronization detection (synchronization establishment)"
In other words, frame synchronization is achieved by assuming that this is not the case, as “synchronization not detected (synchronization not established)”.

The synchronous timing control operation includes:
In the case of "synchronization detection (synchronization establishment)", all the correlation value integration results are divided into a correlation value integration result up to the first half (S27) and a correlation value integration result (S28) of the second half, and these are compared. (S29) If the integration result up to the first half is larger, the symbol data is "+1/8 sampling unit", and if the integration result in the second half is larger, "-1".
/ 8 sampling unit ”is determined as the synchronization timing correction amount (S30, S1). If there is no difference between the correlation value integration result of the first half and the correlation value integration result of the second half, the correction amount to be determined is set to zero (S32). Then, an operation of correcting the next reception position using the correction amount is performed to adjust the response speed of the synchronization timing control (S33). As a result of integrating all the correlation values, if a correlation value integration result exceeding a preset threshold value cannot be detected, a synchronization detection operation is performed at a reception timing position obtained at the time of the synchronization timing control immediately before a certain period. Then, the operation of detecting the synchronization symbol is repeated until the synchronization can be detected again. If the synchronization cannot be further detected, the AFC control operation and the search for the reception channel are performed again.

Normally, the reception position is moved up to the symbol unit level by AGC control or AFC control. Therefore, when "synchronization detection (synchronization establishment)" information is continuously obtained, the reception status is relatively high. Are stable, and the reception timing correction in this case does not need to be largely moved. Therefore, the response of the synchronization timing control operation is delayed by setting the "correction amount in ± 1/8 sampling unit" of the received symbol sampling unit as the reception timing correction amount (S33) . If the prior art, in such a state frequently come up in the "synchronization undetected (not-synchronized)" information, will be receiving situation is unstable, following the reception status of this <br/> Whereas the correction of the reception timing position is frequently performed, the response speed of the synchronization timing control operation is suppressed, so that unnecessary synchronization timing control operation is not performed. Therefore, in this embodiment,
Receives the "correction amount in ± 1/8 sampling units"
As the timing correction amount, by adjusting the response speed of the synchronous timing control operation, even if the received signal fluctuates rapidly due to factors such as multipath, fading, and delay dispersion, the received timing position fluctuates and the synchronization symbol Malfunction due to erroneous detection can be prevented.

Note that the setting of the threshold value for determining whether "synchronization detection (synchronization establishment)" or "synchronization non-detection (synchronization not established)" is performed during the synchronization detection operation depends on software processing. It is possible to set a value in advance. Alternatively, by partially changing the software processing configuring the operation of the MCPU 11, the setting can be performed from the operation unit 12 and the current setting status can be confirmed on the display unit 13.

[0021]

As described above, according to the present invention, as a synchronization detection operation at the time of reception performed in the MODEM section of a digital MCA mobile radio, a correlation value is calculated for data near a received synchronization symbol, and all the results are obtained. Integration is performed, and “synchronization detection (synchronization establishment)” and “synchronization non-detection (synchronization end establishment)” are determined according to the magnitude of the integration result. In the case of “synchronization detection (synchronization establishment)”, the synchronization timing control operation is performed. If the first half correlation value integration result is compared with the second half correlation value integration result and there is a difference between them, the "correction amount in ± 1/8 sampling timing unit" of the symbol data sampling unit is used. and the control amount, if there is no difference to output the control amount as zero, then by adjusting the response speed of the synchronous timing control operation, received in fading Even when conditions are such that degradation, fluttering of the reception timing position, and there is an effect that it is possible to prevent a malfunction due to synchronization symbol erroneous detection.

Further, by performing such a synchronization timing control operation, there is an effect that the received data or the voice quality during a call can be improved in the case where the receiving condition is deteriorated.

[Brief description of the drawings]

FIG. 1 shows a digital M according to an application example of an embodiment of the present invention.
It is a block diagram showing CA mobile radio equipment.

FIG. 2 is a flowchart showing a synchronization detection and synchronization timing control method according to the embodiment in the application example shown in FIG. 1;

FIG. 3 is a flowchart illustrating a conventional synchronization detection and synchronization timing control method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Radio part 3 MODEM part 4 Channel codec part 5 Audio codec part 6 PCM codec part 7 Amplifier 8 Speaker 9 Microphone 10 Amplifier 11 MCPU part 12 Operation part 13 Display part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 7/26 H04Q 7/00-7/38

Claims (3)

(57) [Claims] 1. A method for detecting and synchronizing a synchronization of a digital MCA mobile radio having a MODEM unit, comprising: correcting a symbol unit used for control of the synchronization detection and synchronization timing control performed by the MODEM unit and correcting a sampling timing unit thereof. As a method of setting the amount, first, all the correlation values obtained at the time of the synchronization detection operation are integrated, and the integration result is referred to as “synchronization detection (synchronization establishment)” according to the magnitude.
And “synchronization not detected (synchronization not established)”, and in the case of the “synchronization detection (synchronization established)”, comparing the correlation value integration result of the first half with the correlation value integration result of the second half When there is a difference between them, the correction amount is switched and output in the symbol unit and the sampling timing unit.
A synchronization detection and synchronization timing control method. 2. A method for detecting synchronization and controlling synchronization timing of a digital MCA mobile radio having a MODEM unit, wherein a correlation value is calculated for data near a received synchronization symbol as a synchronization detection operation at the time of reception performed by the MODEM unit. Then, all the results are integrated, and “synchronization detection (synchronization establishment)” and “synchronization non-detection (synchronization unestablishment) are determined based on the magnitude of the integration result. As the timing control operation, the first half of the correlation value integration result is compared with the second half of the correlation value integration result, and if there is a difference between them, the sampling unit of the synchronization symbol data is “± １ ／ sampling”. synchronization detection及correction amount of the timing unit "and as its controlled variable, if there is no difference, characterized in that to output the control amount as zero Synchronization timing control method. 3. A method for detecting synchronization and controlling synchronization timing of a digital MAC mobile radio having a MODEM unit, wherein the MODEM unit performs baseband conversion of a digital reception data sequence fetched from the radio unit during reception as a synchronization detection operation. In order to detect a synchronization symbol, which is known information included in advance, a correlation calculation window (correlation value calculation target range) is used for the data around the received synchronization symbol in units of symbol data sampling.
The correlation values are sequentially calculated while shifting the correlation value, and the obtained correlation values are integrated. If the result of integrating all the correlation values in the vicinity of the synchronization symbol exceeds a preset threshold value, “Synchronization detection (synchronization detection Established) ", and if not, frame synchronization is assumed by assuming that" synchronization is not detected (synchronization not established) ". As a synchronization timing control operation,
In the case of the "synchronization detection (synchronization establishment)", all the correlation value integration results are divided into a correlation value integration result up to the first half and a correlation value integration result of the second half, and the comparison is performed. If the correlation value integration result up to is larger, then “+「 sampling unit ”of the symbol data is used. If the correlation value integration result of the latter half is larger,“ −1 ”is used.
/ 8 sampling unit ”is determined as the synchronization timing correction amount to be obtained. If there is no difference between the correlation value integration result of the first half and the correlation value integration result of the second half, the synchronization timing correction amount to be determined is zero. sync detection and synchronization timing control method comprising the TURMERIC line operation to correct the next of the received position using the correction amount.