JPH0621845A - Reception control circuit for voice operating system - Google Patents

Abstract

PURPOSE:To reduce the circuitry and to obtain the effect of duplicate supervision with respect to the reception control circuit for the voice operating system used for, e.g., a digital automobile telephone system. CONSTITUTION:The mobile body communication system sending a transmission signal of a non-voice signal format to a base station when a speech voice signal is in the non-voice state is provided with a comparator means 3 comparing an output level of a reception electric field strength data amplifier section with a set threshold level in terms of symbols and outputting a relevant result of comparison and a control means 4 comprising a BTR control section 41 sending a BTR hold signal to a BTR 23 when an output of the comparator means 3 is at an L level and sending a release signal releasing the BTR hold signal to the BTR 23 when the output of the comparator means 3 is at an H level and comprising a detection signal generating section 42 sending a VOX detection signal when the result of comparison in applied 1st, 2nd and 3rd timing signals indicates respectively L, H, L levels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reception control circuit for a voice operating system used in, for example, a digital car telephone system.

A voice operating system (hereinafter abbreviated as VOX) was devised as a means for reducing the power consumption of a mobile device. As will be described later, the mobile device during a call makes a call when the call voice is silent. The control for stopping the transmission of information is performed.

Therefore, on the receiving side of the base station, (1) a means for preventing out-of-synchronization of the bit timing recovery due to the influence of noise, etc. in the guard bit (G) part where there is no received radio wave, and (2) the VOX state. And a means for recognizing that

Normally, the VOX recognition means is to detect a postamble pattern for predicting the start of VOX and a preamble pattern for predicting the end of VOX, which are transmitted from the mobile station.

However, since both the postamble pattern and the preamble pattern are as long as 224 bits, the scale of the VOX recognition circuit that detects these patterns becomes enormous, and there is a demand for miniaturization of the base station and low power consumption. Can't meet. Also, since the voice codec circuit on the network side is also provided with the VOX detection function based on the same method, the effect of double monitoring by both the base station and the network side is diminished.

Therefore, it is necessary to reduce the circuit scale and obtain the effect of double monitoring.

[0007]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional example (base station receiving side), FIG. 5 is an uplink transmission signal format diagram (bit allocation), (a) is a call state, and (b) is a VOX state. is there.

FIG. 6 is an explanatory view of the VOX control operation (on the side of the mobile unit), where (a) shows the case where the voiced state is changed to the silent state.
(b) is during a silent state, and (c) is a case where the silent state changes to a voiced state.

The description of FIGS. 4 to 6 will be given below. First,
As shown in Fig. 5, when there is a voice to be transmitted, the mobile station in communication has 112 bits in the TCH (information channel) portion in the 280-bit area of one slot, as shown in Fig. 5 (a). The call information of × 2, the guard time for burst transient response in the shaded area
(R), preamble, sync word, line control data, and other control information (hatched areas in the figure) are inserted respectively.
A bit transmission signal is generated and sent to the base station.

Since 6 guard bits (G) are provided, transmission is stopped during this period. However, when there is no audio to be sent, 108 bits, 118 bits of guard bits (G) and 4 bits of burst transient response guard bits (R) are provided before and after the control information, as shown in Fig. 5 (b). Therefore, the transmission is stopped during this period. In this way, in the silent state, the transmission signal transmission time is 1 / th compared to the voiced state.
It becomes 5.

Next, as shown in FIG. 6 (a), the voice becomes silent at the time of # 3 of 20 msec timing (indicating the period of the sub-frame). It is assumed that it is detected at some time (see Fig. 6 (a)-). As a result, the TCH portion of FIG.
2 bits + 112 bits) postamble (POST) and 1
Slot-shifted over 2 slots (112 bits +
Sends 112-bit) background noise (background) to the base station (
Figure 6 (a)-).

The reason for inserting the background noise is that the noise generated by the decoder on the exchange side is heard by the user when there is no sound, but since this noise is not a soft sound, a soft noise can be heard. .

After that, during the silent state, the mobile unit operates as shown in FIG.
The control information is transmitted in the transmission signal format of (b) as described above. For example, once a second, the postamble (POS
T) and background noise (background) are sent to the transmission signal format of Fig. 5 (a) (see Fig. 6 (b)-,).

However, as shown in FIG. 6 (c)-
The voice became voiced at the ec timing # 2, but if this was detected at the timing # 3 of the encoding process, the result of FIG.
In the TCH part of (a), (112 bits +
After transmitting the 112-bit) preamble (PRE) to the base station, the encoded call information of # 3 and # 4 is transmitted in the next slot (see FIG. 6 (c)-).

On the other hand, at the base station, it is known that if the post preamble is detected, the VOX state is set after 2 slots, and if the preamble is detected, the VOX state is released from the next slot.

Now, in FIG. 4, the detector 11 extracts the baseband signal from the received signal and sends it to the pattern detector 11. The pattern detector stores the postamble and preamble patterns, so if it detects that the applied baseband signal is in the first half or the second half of the postamble, the corresponding detection signal is bit-recovered (hereinafter abbreviated as BTR). ) Send to the control unit 13.

When the postamble detection signal is applied, the BTR control section 13 sends an L level BTR hold signal which holds the state as it is from the next slot to the BTR 14. As a result, the BRT retains the BTR operating state immediately before silence.

Further, when the pattern detection section detects the preamble pattern, it sends a preamble detection signal to the BTR control section. The BTR control unit determines that the next slot will change to the voiced state, and sends an H level release signal to the BTR to release the applied BTR hold signal.
As a result, a reproduction clock that follows the change point of the baseband signal is generated from the next slot and is supplied to each necessary unit.

That is, in the base station that has detected the VOX period,
The BTR hold signal is generated in synchronization with the frame timing in order to maintain the BTR synchronization in the G bit and R bit parts in VOX (see Fig. 5 (c)).

[0020]

As described above, since VOX control such as VOX detection and BTR control accompanying it is performed by detecting the postamble pattern and preamble pattern sent from the mobile station, The following problems occurred. (1) Since the pattern is as long as 224 bits and is sent over two slots, the detection circuit including pattern protection (error tolerance) becomes enormous. (2) Since the detection circuit for the postamble pattern and the detection circuit for the preamble pattern are required independently, two detection circuits are required. (3) Since VOX background noise processing is performed in the exchange on the network side, the same VOX detection is performed in the exchange (the background noise is detected by ORing with the detection result on the base station side). However, even though a dual monitoring system for the base station and the exchange can be created, the effect is weak because the same monitoring method is used.

That is, there is a problem that the circuit scale is large and the effect of double monitoring is weak. An object of the present invention is to reduce the circuit scale and to obtain the effect of double monitoring.

[0022]

FIG. 1 is a block diagram showing the principle of the present invention. In the figure, 21 is a detection unit that detects a received signal and extracts demodulated data in a baseband band, 22 is a received electric field intensity data amplification unit that outputs an output corresponding to a reception level, 23
Is a bit timing recovery unit that detects a change point of the output of the detection unit and generates a reproduction clock.

Reference numeral 3 compares the magnitude of the output level of the received electric field strength data amplifier with the set threshold value in symbol units. When the output level is larger than the threshold value, it is H level, and when it is smaller than the threshold value, it is H level. It is a comparison means for transmitting the L level comparison result.

Reference numeral 41 indicates a bit timing recovery hold signal for holding the immediately preceding bit timing recovery operation when the output of the comparison means is at L level, and cancels the transmitted bit timing recovery hold signal when at H level. It is a bit timing recovery control unit that sends a cancellation signal to the bit recovery timing unit in symbol units.

Reference numeral 42 generates first, second, and third timing signals indicating designated positions near the center of the front guard portion, the control information portion, and the rear guard portion, respectively. 2, if the comparison result in the third timing signal is L level, H level, L level, a detection signal generation part for transmitting a voice operating system detection signal, 4 is a bit timing recovery control part and detection signal generation It is a control means having a portion.

[0026]

[Operation] Here, in the frame format of FIG.
There is no received data at the G-bit and R-bit positions, and since it is below the threshold value set near the reception sensitivity point, there is a possibility that the bit timing recovery (BTR) unit may be erroneously pulled in due to noise such as thermal noise.

In order to prevent this, the present invention determines the magnitude of the received electric field strength and the threshold value on a symbol-by-symbol basis, and when the determination result is small, the BTR control portion in the control means immediately before the symbol unit. BTR control signal (that is, BTR
Send hold signal).

Further, the recognition of whether the VOX state or not
If the comparison results at the second and third timings are L level, H level, and L level, it is determined that a VOX transmission signal having a front guard portion, a control information portion, and a rear guard portion has been received. .

This eliminates the need for a circuit for detecting the postamble pattern and the preamble pattern, and since the monitoring method is different between the base station and the exchange, the circuit scale can be reduced and the double monitoring effect can be obtained.

[0030]

2 is a block diagram of an embodiment of the present invention, and FIG.
FIG. Hereinafter, assuming that the VOX state, it is shown in FIG.
The operation of Fig. 2 will be described with reference to.

First, the mobile unit is shown in FIG. 5 (a) or FIG. 5 (b).
The transmission signal of the format is sent to the base station. The receiving side of the base station receives the above-mentioned signal, frequency-converts it into a reception signal in the intermediate frequency band, and adds it to the detection unit 21. The detection unit demodulates the received signal and extracts the demodulated data in the baseband as shown in Fig. 3-and the bit timing recovery unit.
(Hereafter, abbreviated as BTR part) Send to 23. The BTR section detects the change point of the input data and generates the recovered clock.

Further, the received electric field intensity data amplifier (hereinafter,
(RSS amplifying section is omitted.) 22 adds the output corresponding to the received electric field strength to the comparator 31 by using the received signal in the intermediate frequency band, but the value near the demodulatable receiving level is applied as the threshold here. is doing.

Therefore, the comparator is RS as shown in FIG.
The magnitude of the output of the SI amplifier and the threshold value are compared on a symbol-by-symbol basis. When the former is smaller than the latter, the L level is compared, and when it is larger, the H level comparison result is compared to the BTR control section (not shown). ).

Since a symbol timing (not shown) is externally applied to the comparator, symbol-by-symbol comparison is performed using this timing. BTR in control unit
The control part 41 externally corresponds to the front guard part (guard bit G + guard time for burst transient response R) 112.
Bit L, 50 bits H corresponding to the control information part and 118 bits L corresponding to the rear guard part (G) are applied as the BTR hold timing (Fig. 3
-Ref.), And is configured to take the logical sum of this BTR hold timing and the comparison result from the comparator and send it to the BTR.

Therefore, when the comparison result of the L level is added from the comparator while the BTR hold timing is at the L level, the L level control signal, that is, the BTR hold signal for holding the immediately previous BTR operation is displayed in the symbol unit. Is sent to the BTR.

However, while the BTR hold timing is at the H level, even if the comparison result is added from the comparator, all are masked, and the H level control signal, that is, the normal BTR
A signal to perform the operation is sent to the BTR (see Figure 3-).

Here, the reason for controlling the BTR operation on a symbol-by-symbol basis is that when the entire pattern is detected and the BTR operation is controlled, the control is delayed by one slot, so the data of one slot being detected is wasted. Therefore, in order to reduce the delay, the data is wasted by only one symbol by processing in symbol units. In addition, since the BTR unit normally operates with a time constant of several tens of symbols, a control delay of one symbol does not pose a problem.

On the other hand, the detection signal generating section 42 in the control section
The 112-bit front guard part (L level state), the 50-bit control information part (H level state) and the 118-bit rear guard part (L level state)
If the level of the comparison result at points (a), (b), and (c) is L level, H level, or L level, the VOX signal is transmitted assuming that it is in the VOX state. For example, if you invert the comparison results at points (a) and (c), and latch the comparison results at points (b) and take the logical product, you can obtain the logical product of H. To do.

That is, the comparison unit and the control unit for generating the BTR hold signal from the comparison result and for judging the VOX state by latching the comparison results of the three points in one slot are sufficient for determining the VOX state. Detection and BTR halt control can be performed.

Therefore, the conventional postamble pattern,
Compared with VOX detection and BTR hold control by detecting the preamble pattern, the same function can be realized on a significantly smaller scale. Also, because the detection is performed by a method different from the detection of the VOX status in the exchange on the network side, the detection result can be complemented and the effect of double monitoring can be enhanced.

[0041]

As described in detail above, according to the present invention, there is an effect that the circuit scale can be reduced and the effect of double monitoring can be obtained.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of FIG. 2;

FIG. 4 is a block diagram of a conventional example (base station receiving side).

[Fig. 5] In the transmission signal format diagram (bit allocation) of the uplink, (a) is a call state, (b) is a VOX state, and (c) is a BTR.
It is a control signal explanatory drawing.

[Fig. 6] In the VOX control operation explanatory diagram (mobile unit side), when (a) changes from the voiced state to the silenced state, (b) changes from the silenced state to (c) changes from the silenced state to the voiced state. This is the case when it changes.

[Explanation of symbols]

3 Comparing means 4 Control means 21 Detection section 22 Received electric field strength data amplification section 23 Bit timing recovery section 41 Bit timing recovery control section 42 Detection signal generation section

Claims (1)

[Claims] 1. A detection unit (21) for detecting a reception signal to extract demodulation data in a baseband band, a reception electric field intensity data amplification unit (22) for outputting an output corresponding to a reception level,
When it is detected that a base station having a bit timing recovery unit (23) for generating a reproduction clock by detecting a change point of the output of the detection unit and a call voice to be transmitted to the base station are in a silent state. , A silence signal format composed of a front guard part indicating a transmission stop range, a control information part having a predetermined bit length, and a rear guard part indicating a transmission stop range after transmitting a transmission signal of a predetermined format according to a predetermined procedure. In a mobile communication system provided with a mobile device having a function of transmitting the transmission signal of, the magnitude of the output level of the received electric field intensity data amplification section and the set threshold value are compared in symbol units, When the output level is higher than the threshold value, it is H level, and when it is lower than L level
A comparison means (3) for sending the level comparison result, and a bit timing recovery hold signal for holding the immediately preceding bit timing recovery operation when the output of the comparison means is at the L level A bit timing recovery control part (41) for sending a release signal for releasing the bit timing recovery / hold signal to the bit recovery timing part in symbol units, and an area of the front guard part, control information part, and rear guard part , 1st, 2nd indicating designated positions near the center, respectively
A detection signal for generating a third timing signal and transmitting a voice operating system detection signal if the comparison result of the first, second, and third timing signals is L level, H level, or L level. A voice unit characterized by having a control means (4) consisting of a generation part (42)
Reception control circuit for operating system.