JPH09271056A - Mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the service quality during speech by not commanding radio channel changeover to each channel till detection of a silence state is informed from a radio base station thereby avoiding momentary interruption of conversation at the changeover. SOLUTION: When an idle channel is in existence in a transfer destination zone, a modulation detection section 27B of a base station 2 monitors a modulation state of a demodulation section 24C and detects 'modulation interruption', then the detection section informs 'interrupted modulation of receiver 24' to a control section 26. The control section 26 receiving this signal informs it to an exchange station via a radio channel control station. The exchange station receiving this notice sends a 'channel switching signal' to a mobile equipment 1 to select a new channel for an incoming channel through a control channel of the radio base station 2. The mobile equipment 1 informs this instruction to a channel changeover section 12B by a control signal CHX1 of the control section 16. The channel changeover section 12B receiving the control signal CHX1 selects the new incoming channel.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system, and more particularly to an uplink channel and a downlink channel which are divided into two parts.
A mobile phone and a mobile phone for making a call by connecting a mobile device and a radio base station through a heavy radio communication channel, and the radio base station is connected to a mobile telephone switching center or a fixed station through a radio circuit control station. The present invention relates to a mobile communication system such as a telephone.

[0002] In recent years, with the spread of mobile communication systems such as analog or digital type automobile telephones and mobile telephones, improvement of service quality during a telephone call is required.

[0002]

2. Description of the Related Art FIG. 11 shows a configuration example between a mobile telephone and a fixed network of a generally known mobile communication system.
The mobile device 1 in the radio zone A of the radio base station 2 is connected to the base station 2 by the radio channel C (uplink and downlink channels),
Further, this base station 2 is connected to a fixed network exchange station 6 via a radio network control station 4 and a car telephone exchange station 5. The base station 3 that covers the wireless zone B is connected to the control station 4.

FIG. 12 shows a configuration example of a mobile device 1 and a radio base station 2 of a car telephone in a conventional mobile communication system, and the mobile device 1 and the radio base station 2 have the same internal configuration.

That is, the voice signal input from the voice input unit 11 of the mobile unit 1 to the modulator 12A of the transmitter 12 is
The signal is modulated by the modulation unit 12A and sent to the channel switching unit 12B. This modulated signal is sent to the power amplification unit 12C in the upstream channel designated by the control signal CHX1 from the control unit 16 in the channel switching unit 12B, amplified, and sent to the antenna 13.

The voice signal received by the antenna 23 of the base station 2 via the uplink channel of the wireless communication channel is amplified by the receiving high frequency amplifier 24A of the receiving device 24 of the base station 2 and sent to the channel switching unit 22B.

In the channel switching unit 24B, the reception signal is sent to the demodulation unit 24C on the upstream channel designated by the control signal CHX3 from the control unit 26 (this corresponds to the control signal CHX1 from the control unit 16). , This demodulator 24C
Is demodulated by and transmitted to the audio signal output unit 25.

The voice signal input from the voice signal input unit 21 of the base station 2 to the transmitter 22 is a control signal CHX3 from the control unit 26 in the base station 2 and from the control unit 16 in the mobile unit 1. Is transmitted to the signal output unit 15 via the receiving device 14 of the mobile device 1 in the downlink channel designated by the control signal CHX1 of.

In the mobile unit 1 and the base station 2,
Switching between the up and down channels is simultaneously designated by the control units 16 and 26, respectively.

To switch channels during a call, in FIG. 11, (1) switching is performed in a wireless zone within the same wireless circuit control station, and (2) switching is performed within the same car switching center but over different wireless circuit control stations. With the case
(3) There are cases where switching is performed across two car exchanges.

An example of the control operation in the case of switching in the wireless zone in the same wireless circuit control station of the above (1) will be described below with reference to the flowchart of FIG. In addition, in the case of other channel switching, the above-mentioned (2) and (3) require a new signal transmission / reception, but it is essentially the same as the case of (1).

First, in FIG. 11, the mobile unit 1 is connected to the radio base station 2
Assuming that the mobile station 1 moves from the wireless zone A to the wireless zone B of the wireless base station 3, the base station 2 constantly monitors the signal reception level from the mobile device 1 and moves when the reception level becomes equal to or less than a specified value. Knowing that the machine 1 is moving out of its own wireless zone A, the wireless network control station 4 is notified of the decrease in level.

Upon receiving this notification, the control station 4 is in the wireless zone A.
And base stations in the wireless zone around it (eg, base station 3)
To monitor the reception level of the communication channel of the mobile device 1.

Receiving this command, each base station measures the reception level of the communication channel from the mobile device 1 and reports the result to the control station 4.

The control station 4 receiving this reception level report
It is determined that the mobile device 1 has moved to the wireless zone having the highest reception level (step S21 in FIG. 13). However, if this wireless zone is the original wireless zone A, the following channel switching operation is not performed because there is no movement of the mobile device 1 between zones.

Assuming that the radio zone of the highest reception level is zone B of the radio base station 3, the line control station 4 selects one free communication channel in zone B and instructs the car telephone exchange 5 to control the station. 4 is instructed to switch from the channel of wireless zone A in communication to the channel of wireless zone B.

The switching center 5 conducts a wired continuity test with the wireless base station 3 for the designated communication channel, and if the result is good, the wireless base station 2 determines that there is an empty channel (step S22 in the figure). Send a channel switch signal to switch to a new channel. When there is no free channel, the call is forcibly ended (step S27 in the figure).

In accordance with this instruction, the mobile station 1 simultaneously switches the up and down channels of the new communication channel (step S23 in the figure).

Another base station 3 conducts a continuity test of a new channel with the mobile device 1 (step S24 in the figure).

If the continuity test is good, the mobile telephone exchange station 5 switches the communication path from the old channel in the wireless zone A to the new channel in the wireless zone B and continues the communication (step S25 in the figure).

If the continuity test is not good, another free channel is searched for (step S26 in the figure), and if there is a free channel, the process proceeds to step S23, and the same processing is executed thereafter. If there is no free channel, the call is forcibly ended (step S27 in the figure).

[0021]

In such a conventional mobile communication system, when the switching center 5 sends out a "channel switching signal" and the mobile unit 1 switches to a new channel, a continuity test in a wireless section, 0.7 to 0.8 during the period of switching the communication path (steps S23, 24, 26 in the figure)
A momentary disconnection of the call path occurs for about a second, and the conversation of the caller is interrupted at this time.

In digital mobile communication systems, there has been proposed a method for switching channels without interruption by establishing a time slot synchronization method (for example, Fujino et al., "Local Network Synchronization Method"). Study of non-instantaneous hand-off using "The IEICE Autumn Meeting B-
265, etc.), but there are problems that the configuration is complicated and that it cannot be applied to an analog mobile communication system.

Therefore, according to the present invention, the radio network controller notified via the radio base station that the reception level from the mobile station has fallen below the threshold value is transmitted from the mobile station to the adjacent base station of the radio base station. In the mobile communication system instructing the wireless base station that has detected the maximum receiving level and the mobile station to switch the wireless channel through the switching center, the channel is switched during a call. The aim is to improve the quality of service during communication by eliminating interruptions in conversation.

[0024]

[Means for Solving the Problems]

[1] To achieve the above object, in the mobile communication system according to the present invention, first and second silence states in which the wireless base station individually detects the silence state of the call voice in the uplink channel and the downlink channel, respectively. The wireless circuit control station is provided with a detecting means, and the wireless channel control station gives an instruction to switch the wireless channel to each channel until the wireless base station notifies the wireless channel control station that the silent state is detected in the upstream channel or the downstream channel. It is characterized by not performing.

Usually, the average time of silent periods and conversation periods of Japanese conversation are 1.64 seconds and 2.221, respectively.
Seconds (Source: Tanaka et al., "Japanese conversation on / off session")
The Institute of Electronics, Information and Communication Engineers, Vol.J72-BI No.4, p323-330).

That is, the silent state detecting means detects the timing when the voice of the upstream channel is in the silent state and switches the upstream channel, and similarly detects the timing when the voice of the downstream channel is in the silent state. If the downlink channel is switched by means of this, instantaneous interruption of the call at the time of channel switching will be eliminated.

When the uplink channel and the downlink channel are switched at different switching timings in this way, two sets of radio communication channels are occupied during the channel switching, but the period is at most 1 to 2 seconds, which affects communication traffic. Almost never.

[2] In the above-mentioned present invention [1], the first and second silence state detecting means are provided in the mobile station instead of the radio base station, and the silence is transmitted from the mobile station. It is also possible to notify the wireless line control station of the status via the wireless base station.

[3] In the present invention, the wireless base station is provided with a silent state detecting means for detecting a silent state of a call voice in an up channel or a down channel, and the wireless line control station is in the silent state. Is detected from the wireless base station with the additional condition that the wireless channel switching instruction is given to the channel that is the detection target of the silent state, and the channel that is not the detection target is detected. Is characterized in that when the silent state detecting means detects a voiced state, the wireless channel switching instruction is given.

That is, one of the upstream channel and the downstream channel is provided with a silent state detecting means, and the non-silent state of the channel detected by the silent state detecting means, that is, the other channel is regarded as a silent state. Then, the channel is switched, but the channel in which the voiced state is detected is not switched.

The channel is switched only after the voiced state becomes silent.

[4] In the above-mentioned present invention [3], the silent state detecting means is provided in the mobile station instead of the radio base station, and the silent state (and the voiced state is transmitted from the mobile station). ) Can be notified to the wireless line control station via the wireless base station.

[5] Furthermore, in the present invention, the radio base station is provided with a first silence state detecting means for detecting a silence state of the communication voice in one of the up channel and the down channel, and the mobile station is The wireless line control station is provided with a second silence state detecting means for detecting a silence state of the call voice on the other channel, and the radio network controller reports that the silence state is detected on the uplink channel or the downlink channel. Alternatively, the wireless channel switching instruction is issued to each channel only when notified by the mobile station.

That is, the silent state may be detected not only by the base station or the mobile station as described above, but by both the base station and the mobile station for both channels.

[6] In the present invention, the above-mentioned present invention [1],
In [2] or [5], the first silence state detecting means detects the silence state depending on the presence or absence of the modulation signal of the modulating portion, and the second silence state detecting means causes the modulation signal of the demodulating portion or The silent state can be detected by the presence or absence of the demodulated signal.

[7] In the present invention according to the above-mentioned [3] or [4] of the present invention, the silent state detecting means determines the presence or absence of the modulation signal of the modulation section or the modulation signal or the demodulation signal of the demodulation section. The silent state may be detected.

[8] Furthermore, in the present invention according to the above-mentioned [6] or [7] of the present invention, the transmission signal of the power amplification section is used in place of the modulation signal of the modulation section, and the modulation signal or demodulation of the demodulation section is used. It is also possible to use the received signal of the high frequency amplification section instead of the signal.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment (1) of a mobile device 1 and a radio base station 2 in a mobile communication system according to the present invention.
In contrast to the conventional example of FIG. 12, the modulation unit 22A and the control unit 2 of the wireless base station 2 are used as silence state detection means.
A modulation detection unit 27A connected to No. 6 and a modulation detection unit 27B connected to the demodulation unit 24C and the control unit 26 are added.

That is, the mobile unit 1 according to the present invention and FIG.
In the conventional channel switching operation of the mobile device 1, when the modulation detecting unit 27A detects "modulation break" of the modulating unit 22A, the modulation detecting unit 27A determines to the control unit 26 that there is no voice of the downlink channel and is silent. When the "modulation break" is notified and the modulation detecting unit 27B detects the "modulation break" of the demodulation unit 24C, it is determined that there is no upstream channel voice and the control unit 26 is notified of the "modulation break".

Further, the conventional mobile unit 1 sends the control signal CHX1 from the control unit 16 to the channel switching units 12B and 14B to switch the uplink and downlink channels at the same time, but the mobile unit 1 of the present invention (the configuration is the same as the conventional example). ), The control signals CHX1 and CHX2 are sent from the control unit 16 to the channel switching unit 12
B and 14B are separately sent to switch the up and down channels.

Similarly, in the conventional channel switching operation of the radio base station 2, the control unit 26 switches the uplink and downlink channels at the same time by the control signal CHX3. However, in the present invention, the control unit 26 controls the control signals CHX3, CHX4 to perform the uplink and downlink channels. Downlink channels are switched separately.

In this embodiment, the mobile station 1 is not provided with the silent state detecting means, and the silent state is not detected.

FIG. 2 shows that the mobile unit 1 is moving from the wireless zone A of the wireless base station 2 to the wireless zone B of the wireless base station 3 in the embodiment (1) of FIG. 1 (see FIG. 11). It is a flow chart diagram for explaining a channel switching operation,
The operation will be described below based on this flowchart.

First, steps S1 and S2 are executed in the same manner as steps S21 and S22 in the conventional example of FIG.

After that, when there is an empty channel in the transfer destination zone in step S2 of FIG. 2, the modulation detecting unit 27B of the base station 2 monitors the modulation state of the demodulating unit 24C and "modulation break" unlike the conventional example. When it detects "," the control unit 26 is notified of "modulation interruption of the receiving device 24" (step S3 in the figure).

Upon receipt of this signal, the control unit 26 notifies the exchange 5 via the radio network controller 4 (see FIG. 11).

The exchange 5 which receives this notification is the radio base station 2
The "channel switching signal" is sent to the mobile device 1 through the control channel of 1 to switch the uplink channel to a new channel.

The mobile unit 1 notifies the channel switching unit 12B of this instruction by the control signal CHX1 of the control unit 16. Upon receiving this control signal CHX1, the channel switching unit 12B switches to a new upstream channel (step S4 in the figure).

Another base station 3 conducts a new uplink channel continuity test with the mobile unit 1 (step S in FIG. 3).
5).

If the continuity test is good, then the modulation detector 27A of the base station 2 monitors the modulation state of the modulator 22A,
When the “modulation break” is detected, the control unit 26 displays “Transmission device 22”.
"Discontinuity of modulation" is notified (step S6 in the figure).

Upon receiving this notification, the control unit 26 notifies the switching center 5 via the radio network controller 4 (see FIG. 11).

The exchange 5 which receives this notification is the radio base station 2
A "channel switching signal" is sent to the mobile station 1 through the control channel of 1 to switch the downlink channel to a new channel.

The mobile unit 1 notifies the channel switching unit 14B of this instruction by the control signal CHX2 of the control unit 16. Upon receiving the control signal CHX2, the channel switching unit 14B switches to a new downlink channel (step S7 in the figure).

Another base station 3 conducts a new downlink channel continuity test with the mobile unit 1 (step S in the figure).
8).

If the continuity test is good, the exchange 5 switches the communication path from the old channel in the wireless zone A to the new channel in the wireless zone B and continues the communication (step S9 in the figure).

If the continuity test is not good in steps S5 and S8, another free channel is searched (step S10 in the figure), and if there is a free channel, step S3.
Then, the same processing is executed thereafter. If there is no free channel, the call is forcibly ended (step S11 in the figure).

In FIG. 1, the modulation detectors 27A and 27B as the silent state detecting means are not connected to the modulator 22A and the demodulator 24C of the radio base station 2, but the modulator 12A and the demodulator 14C of the mobile unit 1 are not connected. It is also possible to connect to each of the above to perform modulation detection (silence / sound state detection), notify the detection result to the wireless base station 2, and similarly perform channel switching during communication.

FIG. 3 shows an embodiment (2) of the radio base station 2 of the mobile communication system according to the present invention, in which the modulation detecting section 27A connected to the modulating section 22A and the control section 26 as the silent state detecting means. Is provided.

That is, when the modulation detecting section 27A detects the "modulation interruption" of the modulation section 22A, it judges that there is no downlink channel voice and the control section 26 "modulation interruption of the transmitter 22".
Notify.

On the other hand, the modulation detecting section 27A has a modulation section 22.
Since there is voice in the downlink channel during the period in which "modulation" of A is detected (non-silent state period), it is determined that there is no voice in the corresponding uplink channel (because there is no need for a state in which both parties are talking). Then, the control unit 26 is notified of “upstream voice interruption”.

In this embodiment, the structure of the mobile unit 1 is omitted because it is the same as that of the mobile unit 1 of FIG. 1. Similarly, the mobile unit 1 is not provided with a silent state detecting means,
No silence is detected.

FIG. 4 is a flow chart for explaining the channel switching operation during a call when the mobile device 1 moves from the wireless zone A of the wireless base station 2 to the wireless zone B of the wireless base station 3 (see FIG. 11). It is a diagram, and the operation will be described below based on this flowchart.

First, steps S1 and S2 are the same as steps S21 and S22 of FIG. 13, and if there is an empty channel in the transfer destination zone in step S2, the modulation detecting section 2
7A monitors the modulation of the modulation unit 22A, and when it is not "modulation loss", notifies the control unit 26 of "uplink voice loss" (FIG. 4).
Step S3).

Upon receipt of this signal, the control unit 26 notifies the exchange 5 via the radio network controller 4 (see FIG. 11).

The exchange 5 which has received this notification is the radio base station 2
The "channel switching signal" for switching the upstream channel to the new channel is transmitted to the mobile device 1 via the control channel of.

The mobile unit 1 notifies the channel switching unit 12B of this instruction by the control signal CHX1 of the control unit 16 (see FIG. 1). Upon receiving this control signal CHX1, the channel switching unit 12B switches to a new upstream channel (step S4 in the figure).

Another base station 3 conducts a continuity test of a new channel with the mobile unit 1 (step S5 in the figure).

If the continuity test is good, the modulation detector 27A of the transmitter 22 monitors the modulation of the modulator 22A, and when it detects "modulation break", it notifies the controller 26 of "modulation break of the transmitter 22". A notification is given (step S6 in the figure).

Upon receipt of this notification, the control unit 26 notifies the exchange 5 via the radio network controller 4 (see FIG. 11).

The exchange 5 which receives this notification is the radio base station 2
A "channel switching signal" is sent to the mobile station 1 through the control channel of 1 to switch the downlink channel to a new channel.

The mobile unit 1 notifies the channel switching unit 14B of this instruction by the control signal CHX2 of the control unit 16. Upon receiving the control signal CHX2, the channel switching unit 14B switches to a new downlink channel (step S7 in the figure).

Another base station 3 conducts a new downlink channel continuity test with the mobile unit 1 (step S in the figure).
8).

If the continuity test is good, the exchange 5 switches the communication path from the old channel in the wireless zone A to the new channel in the wireless zone B and continues the communication (step S9 in the figure).

If the continuity test is not good in steps S5 and S8, another empty channel is searched (step S10 in the figure), and if there is an empty channel, step S3.
Then, the same processing is executed thereafter. If there is no free channel, the call is forcibly ended (step S11 in the figure).

It should be noted that, in the embodiment of FIG. 3, the modulation detecting section 27A as the silent state detecting means is not connected to the modulating section 22A of the wireless base station 2, but the demodulating section 24C of the wireless base station 2 or the modulation of the mobile unit 1 is not connected. Modulation detection is performed by connecting to the unit 12A or the demodulation unit 14C, and in the case of the mobile device 1, the inspection result is notified to the radio base station 2 using the control channel, and similarly channel switching during communication can be performed. .

FIG. 5 shows an embodiment (3) of the radio base station 2 of the mobile communication system according to the present invention, which is connected to the power amplifying unit 22C and the control unit 26 of the base station 2 as a silent state detecting means. The transmission interruption detection unit 27C, the reception interruption detection unit 2 connected to the reception high frequency amplification unit 24A and the control unit 26.
7D is provided.

That is, when the transmission interruption detecting section 27C detects the "transmission interruption" of the power amplifying section 22C, it determines that there is no downlink channel voice (silent state), and the control section 26 "transmission interruption".
And the reception disconnection detection unit 27D notifies the reception high frequency amplifier 24
When "reception interruption" of A is detected, it is judged that there is no voice of the uplink channel, and the control unit 26 is notified of "reception interruption".

The configuration of the mobile unit 1 is omitted because it is the same as that of the mobile unit 1 of FIG. 1. Similarly, the mobile unit 1 is not provided with a silent state detecting means, and the silent state is not detected. Not done

FIG. 6 is a flow chart for explaining the channel switching operation during a call when the mobile unit 1 moves from the wireless zone A of the wireless base station 2 to the wireless zone B of the wireless base station 3 (see FIG. 11). It is a diagram, and the operation will be described below based on this flowchart.

First, steps S1 and S2 are the same as steps S21 and S22 of FIG. 13, and when there is an empty channel in the transfer destination zone in step S2, the reception interruption detection section 27D monitors the reception state of the high frequency amplification section 24A. Then, when the “reception interruption” is detected, the “reception interruption” is notified to the control unit 26 (step S3 in FIG. 6).

Upon receipt of this notification, the control unit 26 notifies the exchange 5 via the radio network controller 4. (See FIG. 11).

The exchange 5 which receives this notification is the radio base station 2
A "channel switching signal" is sent to the mobile device 1 via the control channel of 1 to switch the uplink channel to a new channel.

The mobile unit 1 sends this instruction to the channel switching unit 12B via the control signal line CHX1 of the control unit 16 (see FIG. 1). Upon receiving this control signal CHX1, the channel switching unit 12B switches to a new upstream channel (step S4 in the figure).

Another base station 3 carries out a new channel continuity test with the mobile unit 1 (step S5 in the figure).

If the continuity test is good, then the transmission interruption detecting section 27C monitors the power amplifying section 22C, and when it detects "transmission interruption", it sends out a "transmission interruption" signal to the control section 26 (see the same figure). Step S6).

Upon receiving this signal, the control unit 26 notifies the switching center 5 via the radio network controller 4 (see FIG. 11).

The exchange 5 which receives this notification is the radio base station 2
A "channel switching signal" is sent to the mobile station 1 through the control channel of 1 to switch the downlink channel to a new channel.

The mobile unit 1 notifies the channel switching unit 14B of this instruction by the control signal CHX2 of the control unit 16 (see FIG. 1). Upon receiving the control signal CHX2, the channel switching unit 14B switches to a new downlink channel (step S7 in the figure).

Another base station 3 conducts a new downlink channel continuity test with the mobile unit 1 (step S in the figure).
8).

If the continuity test is good, the exchange 5 switches the communication path from the old channel in the wireless zone A to the new channel in the wireless zone B and continues the communication (step S9 in the figure).

If the continuity test is not good in steps S5 and S8, another free channel is searched for (step S10 in the figure), and if there is a free channel, step S
Then, the process proceeds to step 3 and the same process is performed. If there is no free channel, the call is forcibly ended (step S11 in the figure).

In the embodiment shown in FIG. 5, the reception interruption and the transmission interruption are detected by the reception high frequency amplification section 24A and the power amplification section 22C of the radio base station 2, respectively.
It is also possible to connect the reception disconnection detection unit and the transmission disconnection detection unit to the reception high frequency amplification unit 14A and the power amplification unit 12C, respectively, and detect the transmission disconnection or reception disconnection of the downlink or uplink channel.

FIG. 7 shows an embodiment (4) of the radio base station 2 of the mobile communication system according to the present invention, in which the reception interruption connected to the reception high frequency amplification section 24A and the control section 26 as the silent state detecting means. A detector 27D is provided.

That is, when the reception interruption detecting section 27D detects the "reception interruption" of the high frequency amplifying section 24A, it judges that there is no upstream channel voice and notifies the control section 26 of the "reception interruption".
On the other hand, in the state where the reception is not interrupted, there is voice in the uplink channel, and therefore it is determined that "there is no downlink voice" in the corresponding downlink channel, and the control unit 26 is notified of "downlink voice interruption".

The configuration of the mobile unit 1 is omitted because it is the same as that of the mobile unit 1 of FIG. 1. Similarly, the mobile unit 1 is not provided with the silent state detecting means, and the silent state is not detected. Not done

FIG. 8 is a flow chart for explaining the channel switching operation during a call when the mobile device 1 moves from the wireless zone A of the wireless base station 2 to the wireless zone B of the wireless base station 3 (see FIG. 11). It is a diagram, and the operation will be described below based on this flowchart.

First, steps S1 and S2 are the same as steps S21 and S22 of FIG. 13, and when there is an empty channel in the transfer destination zone in step S2, the reception interruption detecting section 27D monitors the high frequency amplifying section 24A, When the “reception interruption” is detected, the control section 26 is notified of the “reception interruption” (FIG. 8).
Step S3).

Upon receiving this notification, the control unit 26 notifies the exchange 5 via the radio network controller 4.

The exchange 5 which has received this notification is the radio base station 2
The "channel switching signal" for switching the upstream channel to the new channel is transmitted to the mobile device 1 via the control channel of.

The mobile unit 1 notifies the channel switching unit 12B of this instruction by the control signal CHX1 of the control unit 16 (see FIG. 1). Upon receiving this control signal CHX1, the channel switching unit 12B switches to a new upstream channel (step S4 in the figure).

Another base station 3 conducts a continuity test of a new channel with the mobile unit 1 (step S5 in the figure).

If the continuity test is good, the reception interruption detector 2
The 7D monitors the high-frequency amplifier 24A, and if it does not detect "reception interruption", it sends a "downlink voice interruption" signal to the controller 26 (step S6 in the figure).

Upon receiving this signal, the control unit 26 notifies the exchange 5 via the radio network controller 4.

The exchange 5 which receives this notification is the radio base station 2
A "channel switching signal" is sent to the mobile station 1 through the control channel of 1 to switch the downlink channel to a new channel.

The mobile unit 1 notifies the channel switching unit 14B of this instruction by the control signal CHX2 of the control unit 16. Upon receiving the control signal CHX2, the channel switching unit 14B switches to a new downlink channel (step S7 in the figure).

Another base station 3 conducts a new downlink channel continuity test with the mobile unit 1 (step S in the figure).
8).

If the continuity test is good, the exchange 5 switches the communication path from the old channel in the wireless zone A to the new channel in the wireless zone B and continues the communication (step S9 in the figure).

If the continuity test is not good in steps S5 and S8, another free channel is searched for (step S10 in the figure), and if there is a free channel, step S3.
Then, the same processing is executed thereafter. If there is no free channel, the call is forcibly ended (step S11 in the figure).

Note that, in FIG. 7, the reception detecting section 27D as the silent state detecting means is replaced by the high frequency amplifying section 2 of the radio base station 2.
It is also possible to connect to the high frequency amplification unit 14A of the mobile device 1 without connecting to 4A, detect the silent state of each channel, and perform channel switching during a call in the same manner.

Further, the power amplifier 22C of the radio base station 2
Similarly, the channel switching during the call can be performed by connecting the transmission interruption detecting section to the power transmission section or connecting the transmission interruption detecting section to the power amplification section 12C of the mobile device 1.

FIG. 9 shows an embodiment (5) of the mobile unit 1 and the radio base station 2 of the mobile communication system according to the present invention.
As a silent state detection means, a modulation detection unit 17A connected to the modulation unit 12A of the mobile device 1 and the control unit 16 and a modulation detection unit 27A connected to the modulation unit 22A of the wireless base station 2 and the control unit 26 are provided. There is.

That is, when the modulation detecting section 17A of the mobile unit 1 detects the "modulation break" of the modulating section 12A, it judges that there is no voice in the upstream channel and notifies the control section 17 of the "modulation break".

On the other hand, when the modulation detecting section 27A of the radio base station 2 detects the "modulation break" of the modulating section 22A, it judges that there is no downlink channel voice and notifies the control section 26 of the "modulation break".

FIG. 10 is a flow chart for explaining the channel switching operation during a call when the mobile device 1 moves from the radio zone A of the radio base station 2 to the radio zone B of the radio base station 3 (see FIG. 11). It is a diagram, and the operation will be described below based on this flowchart.

First, steps S1 and S2 are the same as steps S21 and S22 in FIG. 13, and when there is an empty channel in the transfer destination zone in step S2, the modulation detector 17A of the mobile unit 1 causes the modulator 12A When "modulation break" is detected, the control unit 16 is notified of "modulation break" (step S3 in FIG. 10).

Upon receiving this notification, the control unit 26 notifies the wireless base station 2 by using the control channel, and this wireless base station 2
Further notifies the switching center 5 via the radio network controller 4 (see FIG. 11).

The exchange 5 which receives this notification is the radio base station 2
The "channel switching signal" for switching the upstream channel to the new channel is transmitted to the mobile device 1 via the control channel of.

The mobile unit 1 notifies the channel switching unit 12B of this instruction by the control signal CHX1 of the control unit 16. Upon receiving this control signal CHX1, the channel switching unit 12B switches to a new upstream channel (step S4 in the figure).

Another base station 3 conducts a continuity test of a new channel with the mobile unit 1 (step S5 in the figure).

If the continuity test is good, the modulation detecting section 27A of the radio base station 2 monitors the modulation state of the modulating section 22A,
When the "modulation break" is detected, a "modulation break" signal is sent to the control unit 26 (step S6 in the figure).

Upon receipt of this signal, the control unit 26 notifies the exchange 5 via the radio network controller 4 (see FIG. 11).

The exchange 5 which receives this notification is the radio base station 2
A "channel switching signal" is sent to the mobile station 1 through the control channel of 1 to switch the downlink channel to a new channel.

The mobile unit 1 notifies the channel switching unit 14B of this instruction by the control signal CHX2 of the control unit 16. Upon receiving the control signal CHX2, the channel switching unit 14B switches to a new downlink channel (step S7 in the figure).

Another base station 3 conducts a new downlink channel continuity test with the mobile unit 1 (step S in the figure).
8).

If the continuity test is good, the exchange 5 switches the communication path from the old channel in the wireless zone A to the new channel in the wireless zone B and continues the communication (step S9 in the figure).

If the continuity test is not good in step S5 and step S8, another free channel is searched for (step S10 in the figure), and if there is a free channel, step S3.
Then, the same processing is executed thereafter. If there is no free channel, the call is forcibly ended (step S11 in the figure).

In FIG. 9, the modulation detecting unit is connected to the modulating unit 12A of the mobile unit 1 and the modulating unit 22A of the radio base station 2 to detect the silence states of the up and down channels. The silent state of the power amplifier 1 of the mobile device 1
2C or the high-frequency amplification unit 24A or the demodulation unit 24C of the wireless base station 2 is provided with a silent state detection unit to detect the same, and similarly, the silent state of the downlink channel is demodulated by the demodulation unit 14C or the high-frequency amplification unit 14A of the mobile device 1 or the wireless base station. The second power amplification unit 22C may be provided with a silent state detecting means.

Further, in the above embodiment, the mobile station 1 and the radio base station 2 are provided with the silence state detecting means for the up or down channels, but the radio network controller 4 or the exchange 5 is provided with the silence state detecting means. However, the same is possible.

[0129]

As described above, according to the mobile communication system of the present invention, the mobile station or the radio base station provides the silent state detecting means for individually detecting the silent state of the call voice in the up channel and the down channel. The wireless line control station is configured to issue an instruction for switching the wireless channel to each channel only when the wireless base station notifies that the silent state is detected in the upstream channel or the downstream channel. Since it is configured, it is possible to eliminate instantaneous interruption of conversation at the time of channel switching during a call and contribute to improvement of communication service quality.

[Brief description of drawings]

FIG. 1 is an embodiment (1) of a mobile communication system according to the present invention.
3 is a block diagram showing an example of device configurations of a mobile device and a radio base station in FIG.

FIG. 2 is an embodiment (1) of a mobile communication system according to the present invention.
6 is a flowchart showing the operation of FIG.

FIG. 3 is an embodiment (2) of the mobile communication system according to the present invention.
3 is a block diagram showing an example of the configuration of a wireless base station in FIG.

FIG. 4 is an embodiment (2) of the mobile communication system according to the present invention.
6 is a flowchart showing the operation of FIG.

FIG. 5 is an embodiment (3) of the mobile communication system according to the present invention.
3 is a block diagram showing an example of the configuration of a wireless base station in FIG.

FIG. 6 is an embodiment (3) of the mobile communication system according to the present invention.
6 is a flowchart showing the operation of FIG.

FIG. 7 is an embodiment (4) of the mobile communication system according to the present invention.
3 is a block diagram showing an example of the configuration of a wireless base station in FIG.

FIG. 8 is an embodiment (4) of the mobile communication system according to the present invention.
6 is a flowchart showing the operation of FIG.

FIG. 9 is an embodiment (5) of the mobile communication system according to the present invention.
3 is a block diagram showing an example of device configurations of a mobile device and a radio base station in FIG.

[Fig. 10] Fig. 10 is a flowchart showing the operation of the embodiment (5) of the mobile communication system according to the present invention.

FIG. 11 is a block diagram showing an example of the overall configuration of a mobile communication system common to the present invention and a conventional example.

FIG. 12 is a block diagram showing a device configuration example of a mobile device and a radio base station in a conventional mobile communication system.

FIG. 13 is a flowchart illustrating a channel switching operation during a call in a conventional mobile communication system.

[Explanation of Codes] 1 mobile unit 2, 3 radio base station A, B radio zone 4 radio line control station 5 car telephone exchange station 6 fixed network exchange station 11, 21 voice signal input section 12, 22 transmitter 12A, 22A modulation Part 12B, 14B, 22B, 24B Channel switching part 12C, 22C Power amplification part 14, 24 Reception device 14A, 24A Reception high frequency amplification part 14C, 24C Demodulation part 15, 25 Voice signal output part 16, 26 Control part 17A, 27A, 27B Modulation detecting section 27C Transmission disconnection detecting section 27D Reception disconnection detecting section In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideto Furukawa, 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Kazuo Hase, 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Hidenobu Fukumasa 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (8)

[Claims] 1. A radio network controller notified via a radio base station that a reception level from a mobile unit has fallen below a threshold value, and a radio base station receives from the mobile unit to a base station adjacent to the radio base station. In the mobile communication system instructing to detect the level and, as a result, instructing the wireless base station that has detected the maximum reception level and the mobile station to switch the wireless channel through the switching station, The wireless line control station is provided with first and second silence state detecting means for individually detecting the silence state of the call voice on the downlink channel, and the radio network controller confirms that the silence state is detected on the uplink channel or the downlink channel. A mobile communication system characterized in that the wireless channel switching instruction is given to each channel under the additional condition of being notified by the wireless base station. 2. The method according to claim 1, wherein the first and second silent state detecting means are provided in the mobile station instead of the wireless base station, and the silent state is detected from the mobile station. A mobile communication system characterized by notifying the radio network controller via a station. 3. A reception level from a mobile station to a base station adjacent to the radio base station, the radio circuit control station being notified via a radio base station that the reception level from the mobile station has fallen below a threshold value. In the mobile communication system instructing the wireless base station that has detected the maximum reception level and that instructing the mobile station to switch the wireless channel through the exchange, Equipped with a silent state detection means for detecting the silent state of the call voice on the downlink channel,
The wireless line control station gives an instruction to switch the wireless channel to a channel for which the silent state is detected with the additional condition that the wireless base station notifies that the silent state has been detected, A mobile communication system characterized in that, for a channel that is not a detection target, an instruction to switch the wireless channel is issued when the silent state detecting means detects a voiced state. 4. The silent state detecting means according to claim 3, wherein the mobile station is provided in place of the wireless base station, and the silent state is transmitted from the mobile station via the wireless base station. A mobile communication system characterized by notifying a line control station. 5. A reception level from a mobile station to a base station adjacent to the radio base station, the radio network control station being notified via a radio base station that the reception level from the mobile station has fallen below a threshold value. In the mobile communication system instructing the wireless base station that has detected the maximum reception level and the mobile station to switch the wireless channel through the exchange, as a result, the wireless base station is A second silence state detecting means for detecting the silence state of the call voice on one channel of the channels, and a second silence state detecting means for detecting the silence state of the call voice on the other channel of the mobile station; The wireless line control station is provided with the wireless channel control station for each channel until the wireless base station or the mobile device notifies that the silent state is detected in the upstream channel or the downstream channel. A mobile communication system characterized by not issuing a channel switching instruction. 6. The silent state detecting means according to claim 1, 2 or 5, wherein the first silent state detecting means detects the silent state depending on the presence or absence of a modulation signal of a modulating section, and the second silent state detecting means demodulates. A mobile communication system, characterized in that the silent state is detected by the presence or absence of a modulation signal or a demodulation signal of a part. 7. The mobile communication system according to claim 3, wherein the silent state detecting means detects the silent state based on the presence or absence of the modulation signal of the modulation section or the modulation signal or the demodulation signal of the demodulation section. . 8. The transmission signal of the power amplification unit is used in place of the modulation signal of the modulation unit, and the reception signal of the high frequency amplification unit is used in place of the modulation signal or demodulation signal of the demodulation unit. A mobile communication system characterized by the above.