JP3334393B2 - Wireless telephone communication mode switching method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to switching between communication modes of a portable telephone capable of transmitting and receiving radio waves having two different communication modes.

[0002] In recent years, the demand for mobile communication has increased, and the operation range has been expanded on a large scale. The communication modes include analog and digital. In addition, there are several communication modes even in the case of digital communication. For example, as one example of a mobile phone, VSELP (VectorSummedExcitt) is used.
ing Linear Predictive Cod
e) PDC (Personal Digi) using the method
tal Cellular) and a PH code using the ADPCM method as an example of a cordless telephone.
S (Personal Handy Phone Sy
)).

The VSELP voice compression encoding system transmits multiplexed signals for three channels by one radio wave, and the multiplexed signals are transmitted at a transmission rate of 11.2 kbps.

As shown in FIG. 5 (2), in the case of the VSELP system, a signal has a frame length of 20 msec, and a time lag for converting an analog signal into a VSELP system signal on the transmitting side is approximately two frames. Minutes,
That is, it takes about 40 msec. Similarly, on the receiving side, a similar time lag is required to convert a VSELP signal to an analog signal.
It takes time for sec. As a result, during a call in the VSELP system, the voice of the transmitting telephone subscriber is about 80 msec.
The mobile phone of the receiving side will arrive at the receiving party with a delay.

[0005] In addition, the audio compression coding system called ADPCM is 8 bits × 8 kbps = 64 k per channel.
The transmission rate of 32 kbps per channel is obtained by taking the difference between each bit of the PCM signal at the communication speed of bps and expressing this with 1/2 4 bits.

[0006] Then, as shown in FIG.
In the case of the PCM system, this 8 kbps (125 μs
Although a 4-bit signal is sent during c), when the analog signal is converted to a 4-bit ADPCM signal on the transmitting side, a delay of about 250 μsec, twice as long as 125 μsec, occurs. Similarly, when the signal on the receiving side is converted from an ADPCM signal to an analog signal, a delay of about 250 μsec occurs. In addition, when various delays at the base station and the like are included, the total delay is about 1 msec. With this amount of delay, if the subscriber has a good ear, if the spoken voice becomes an echo and leaks to the receiver, immediately after speaking,
You may hear your voice faintly.

As described above, the ADPCM system and the VSELP
When switching from the ADPCM system to the VSELP system on a line using two communication modes of the system, a delay of about 79 msec occurs.

At present, these communication systems exist separately, and, as shown in the example of FIG. 6, for example, the configuration of a portable telephone system using the VSELP system as an example has a plurality of wireless zones so as to cover a service area. is provided a radio base station BV ₁ to BV ₇ respectively RV ₁ ~RV _7. When the mobile phone 5 moves from a certain wireless zone to an adjacent wireless zone, the mobile phone 5 switches the frequency to the channel of the moved wireless zone and continues communication.

The ADPCM system also has its own unique service area as in the example shown in FIG.
Operated separately. There is a need for a wireless telephone communication mode switching method that operates in combination with the two and automatically switches between a mobile phone and a wireless base station that can support both.

[0010]

2. Description of the Related Art FIG. 7 is a diagram showing an example of a schematic configuration of a conventional device configured by the VSELP method. Actually, there are many wireless zones as shown in FIG. 6, but for simplicity of description, it is assumed that there are two wireless zones.

An analog audio signal from the subscriber telephone 1 is
Radio zone RV via telephone exchange 2 ₁Base station BV
₁And the radio zone RV_TwoBase station BV_TwoYes for both
Transmitted over the wire.

The base station BV ₁ and the base station BV ₂ compress the analog audio signal sent from the telephone exchange 2 according to the VSELP method and send it out on a radio wave. The portable telephone 5 which is moving, when moving within the range of the radio zone RV ₁ receives a radio wave of the base station BV _1. When moving to the radio zone RV ₁ also receives radio waves of the base station BV _2, towards towards the radio base station BV ₂ is a radio base station BV ₁ base station BV ₂ when it becomes better than radio waves I had to switch.

Also, in the ADPCM system, a communication system having a similar configuration has been operated with a unique area.

[0014]

However, in the case of the conventional configuration shown in FIG. 7, a method has been established in which both the VSELP system and the ADPCM system can be received and communication can be performed in a communication mode with better reception. Not.

The present invention solves such a problem.
It is an object of the present invention to provide a wireless telephone communication mode switching method capable of receiving signals of two different communication modes and selecting a signal of an arbitrary communication mode.

[0016]

FIG. 1 is a diagram for explaining the principle of the present invention. The present invention relates to a radio base station that transmits an analog signal from a telephone subscriber in one communication mode via a telephone exchange and a radio base station that transmits a radio wave in another communication mode. A wireless telephone communication mode switching method for a communication line performed between the mobile phone and a mobile phone that receives a mode radio wave.
Radio waves of two different communication modes received by one demodulator are received and demodulated.

Then, a processing delay time difference is calculated from the two demodulated analog audio signals demodulated by the delay time calculating means, and a delay amount corresponding to the calculated delay time is set in a delay circuit on the communication mode side having a small processing delay time. I do.

Also, a receiving section of the telephone exchange opposite to the portable telephone receives two demodulated analog audio signals in two different communication modes and processes the two demodulated analog audio signals by a delay time calculating means. Calculate the delay time difference,
A delay amount corresponding to the calculated delay time is set in the delay circuit on the communication mode side having a short processing delay time.

In this way, the object can be achieved by switching the reception analog signal of two different communication modes to be input by controlling the selection unit by the switching instruction signal from the outside.

Further, a receiving section of the portable telephone and a receiving section of the telephone exchange opposite to the portable telephone are each a silence monitoring section, which monitors speech during a call from a demodulated analog audio signal to detect silence. When confirmed, a silent signal is transmitted.

The silence detecting section sends out a silence information signal when the input audio signal continues for a predetermined time. Also, the switching timing signal generating section generates and outputs a selection timing signal when an external switching instruction signal is input while the silence information signal is being input, and controls the selecting section to input two different communication modes. To switch the received analog signal.

[0022]

According to the present invention, the receiving section of a mobile phone for receiving and demodulating radio waves in two different communication modes is provided with a delay time calculating means, so that the mobile phone receives two different demodulators respectively. When the communication mode radio wave is received and demodulated, the waveforms of the two communication mode analog audio signals demodulated by the delay time calculation means are compared to calculate how much a delay time difference exists between the two, and as a result, As the delay amount information signal.

Also, since the receiving section of the telephone exchange opposite to the portable telephone is provided with the delay time calculating means, the receiving section of the telephone exchange receives the analog voice signals of two different communication modes to be received. The delay time calculating means can compare the waveforms of the analog audio signals in the two communication modes, calculate how much a delay time difference exists between the two, and transmit the resulting delay amount information signal. .

According to the result, by setting a delay circuit for the delay amount of the delay time difference calculated by the delay time calculating means to the analog audio signal on the communication mode side having a short processing delay time, the reception of the two different communication modes can be performed. The delay time of the analog audio signal can be made the same.

By setting the received analog signals of the two different communication modes to the same delay amount in this manner, the two different analog signals can be transmitted without interruption of the sound or without repetitive hearing of the sound.
Communication modes can be switched.

Further, a silence monitoring unit for confirming silence during a call and a monitoring signal output from the silence monitoring unit are input to the outputs of the two demodulators in the receiving unit of the mobile phone, and if silence continues for a certain period of time, silence occurs. Since the silence detecting section for transmitting the information signal is provided, the silence information signal can be transmitted when silence continues for a certain period of time during a call.

Similarly to the receiving section of the mobile phone, a receiving section of the telephone exchange opposite to the mobile phone receives a silent monitoring section for confirming silence during a call and a monitoring signal output from the silent monitoring section. Since a silence detecting unit is provided for sending a silence information signal when silence continues for a certain period of time, a silence information signal can be sent when silence continues for a certain period of time during a call.

Further, since the selection timing signal generating section is provided, when the switching instruction signal is input while the silent information signal is being input, the selection timing signal is generated and output, so that the communication mode can be switched silently.

[0029]

An embodiment will be described with reference to FIGS. FIG. 2 is a diagram showing a communication line configuration example in the present invention, FIG. 3 is a diagram showing a first embodiment of the present invention, and FIG. 4 is a diagram showing a second embodiment of the present invention.

In the figure, 1 is a subscriber telephone, 2 is a telephone exchange,
6 is a mobile phone, 11 and 12 are demodulators, 20 is a delay time calculating means, 21 is a waveform comparing section forming the delay time calculating means 20, 22 is a delay time calculating section forming the delay time calculating means 20, and 31 is a delay time calculating section. A delay circuit, 41 is a selection unit, 51 is a silence monitoring unit, 52 is a silence detection unit, 53 is a selection timing signal generation unit, BA and BV are base stations, and RA and RV are radio zones.

FIG. 2 shows an example of a communication line configuration according to the present invention. In order to simplify the explanation, the VSELP system and the AD
In the PCM system, one wireless zone is used for each. The signal from the subscriber telephone 1 is transmitted from the control station 2 to the VSEL.
Radio zone RV ₁ of the communication system in the P-mode communication mode
When sent to both the radio zone RA ₁ of the communication system of the communication mode ADPCM method.

The base station V ₁ BV ₁ has V in the radio zone RV ₁ .
Radio waves are transmitted by the SELP method, and the base station A ₁ BA ₁ transmits radio waves to the wireless zone RA ₁ by the ADPCM method. Here, for example, the mobile phone 6 is connected to the wireless zone RV _1.
And it has moved to the radio zone RA ₁ from. Mobile phone 6, wireless zone RV which does not overlap with the wireless zone RA _{1
In the area of} only _one , V from base station BV ₁
Although only SELP radio waves can be received,
When the mobile station moves to the wireless zone RV ₁ overlapping A _1, it can also receive the radio wave of the ADPCM system from the base station A ₁ BA ₁ .

Furthermore, the mobile phone 6 is moved toward the center of the radio zone RA _1, VSE from base base station BV ₁
LP system radio waves cannot be received. Here, in the radio zone of the mobile phone 6 and the radio zone RA ₁ and the radio zone RV ₁ overlap, ADPCM from VSELP scheme
Although it is necessary to switch to the system, there is a difference in the arrival time of the signal due to the difference in the system, so that it is necessary to prevent the signal from dropping out or overlapping at the time of switching.

FIG. 3 shows a first embodiment of the present invention.
In the receiving unit of the mobile phone 6, the voice from the subscriber 1 is transmitted in two different communication modes, VSELP system and ADPCM.
Receives radio waves of the system. Then, for example, the waveform comparison unit 2 determines the interval between the peak value of the waveform of the analog audio signal demodulated by the demodulation units 11 and 12 and the next peak value, and the like.
The delay time difference between the two is calculated by the delay time calculation unit 22 based on the comparison information that is the result of the comparison. In the case of the two communication modes used in the present invention, the ADPCM method is the VSE
Since the signal arrives 79 msec ahead of the LP system, a delay circuit 31 for 79 msec corresponding to the delay time difference between the two is set in the ADPCM system.

By setting the delay amount of the delay time difference on the side of the communication mode having a small delay time, the phases of the signals input to the selection unit 41 match.
Even if is switched, the sound is not interrupted or the sound is not repeated.

The timing for setting the delay of the delay circuit 31 is set once when a new portable telephone is registered, provided that the delay times of two different communication modes to be used are always constant and do not change. Then, the delay amount can be fixed in the registered service area.

Further, in order to further increase the accuracy, fine adjustment may be made each time the system is operated. Switching of communication modes is not shown, but during operation, demodulated analog signals of two different communication modes are always monitored, and when the signal level falls below a certain level, an alarm is generated by a lamp display or a sounding sound. In advance, the generation of the alarm may be switched to the timing.

Although not specifically shown, two radio frequencies capable of varying the radio waves of the same communication mode as the prior art, that is, the radio waves of one communication mode of the VSELP system or the ADPCM system are received. , Of course.

FIG. 4 shows a second embodiment of the present invention, in which the communication mode is switched when the audio signal is interrupted on the radio wave transmitting the audio signal. FIG.
In the first embodiment of the present invention, analog voice signals obtained by demodulation by demodulators 11 and 12 are input, and silence during call is monitored by silence monitor 51, and silence detector When the silence continues for a certain period of time at 52, the silence information signal is continuously transmitted to the selection timing signal generation unit 53 until the silence continues.

When the selection instruction signal is input while the selection timing signal generating section 53 is inputting the silence information signal from the silence detecting section 52, a selection timing signal is generated and transmitted to the selection section 41, and the selection timing signal is transmitted to the selection section 41. The communication mode is switched by the unit 41.

By doing so, in the case of switching during a call in the first embodiment shown in FIG. 2, a person with good ears may hear the switching sound faintly as "puzzle". In the switching at the time of silence in the second embodiment, the switching can be performed with absolute silence.

For example, if the voice during a call is interrupted while moving from the wireless zone of the VSELP system with a large delay to the wireless zone of the ADPCM system with a small delay, a switching instruction signal is given to switch from the VSELP system to the ADPCM system. By performing the switching, it is possible to perform the switching without being uncomfortable.

Although not shown, the telephone exchange 2 also monitors the analog audio signal level obtained by demodulating the radio waves received from the mobile phone 6 in two different communication modes in the same manner as the mobile phone 6. An alarm may be generated when the level falls below a certain level, and the alarm may be switched to a timing. Alternatively, a switching signal may be received by the mobile phone 6 and the switching may be performed based on the timing signal. Good.

[0044]

As described above, by using the technique of the present invention, the VSELP communication mode, the ADP
When switching between signals in the CM communication mode, no interruption or repetition of sound occurs, so that call quality can be reduced.

Further, since the communication mode is switched while silence continues during a call, the switching can be performed without being uncomfortable, so that the communication quality can be ensured.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a configuration example of a communication line according to the present invention.

FIG. 3 is a first embodiment of the present invention.

FIG. 4 is a second embodiment of the present invention.

FIG. 5 is a diagram showing a signal of the ADPCM system and a signal of the VSELP system.

FIG. 6 is a diagram illustrating a configuration example of a mobile phone system using a VSELP method as an example.

FIG. 7 is a diagram showing a conventional example using the VSELP method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Telephone subscriber 2 Telephone exchange 5, 6 Mobile telephone 11, 12 Demodulator 20 Delay time calculating means 21 Waveform comparing unit 22 Delay time calculating unit 31 Delay circuit 41 Selection unit 51 Silence monitoring unit 52 Silence detection unit 53 Selection timing signal Generation unit BA, BV Base station RA, RV Wireless zone

Claims (2)

(57) [Claims] 1. A radio base station for transmitting an analog signal from a telephone subscriber in one communication mode via a telephone exchange, and a radio base station for transmitting a radio wave in another communication mode.
A wireless telephone communication mode switching method for a communication line performed between two mobile phones that receive radio waves of the communication mode, wherein a receiving unit of the mobile phone receives two different communications received by two demodulators, respectively. Mode radio wave is received and demodulated, a processing delay time difference is calculated from the two demodulated analog audio signals demodulated by the delay time calculating means, and the delay time calculated by the delay circuit on the communication mode side having a small processing delay time is calculated. The receiving unit of the telephone exchange, which faces the mobile phone, also receives two different demodulated analog audio signals of two different communication modes, and the delay time calculating means sets the two demodulated analog audio signals. Calculate the processing delay time difference, set the delay amount for the calculated delay time in the delay circuit on the communication mode side where the processing delay time is short, and select it with the switching instruction signal from the outside. A wireless telephone communication mode switching method, comprising: switching a received analog signal of two different communication modes to be input by controlling a unit. 2. The mobile telephone according to claim 1, wherein the receiving unit of the mobile telephone and the receiving unit of the telephone exchange opposite to the mobile telephone monitor voice during a call from an analog voice signal demodulated by a silent monitoring unit. When a silence signal is confirmed, a silence signal is sent out. When the audio signal input by the silence detection unit continues for a certain period of time, a silence information signal is sent out. A switching instruction signal is generated, a switching signal is generated and output, and a selection unit is controlled to switch between received analog signals in two different communication modes, thereby switching a wireless telephone communication mode.