JP3555874B2 - Mobile phone system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mobile phone system.
[0002]
[Prior art]
In a mobile phone system, when a mobile communication terminal device such as a mobile phone makes and receives a call, the mobile phone measures the reception level of radio waves transmitted by a plurality of peripheral wireless base stations and transmits the measurement result to the wireless base station. Notice. The wireless base station specifies a wireless channel to the mobile phone so as to specify the highest reception level of the peripheral wireless base stations notified from the mobile phone and perform communication through the wireless base station.
[0003]
[Problems to be solved by the invention]
However, in such a conventional method, a communication failure may occur when an enclave occurs in the service area of the wireless base station.
FIG. 3 is a schematic diagram showing a plurality of wireless base stations and their respective service areas. FIG. 3 shows wireless base stations 102, 104, 106, 108, 110, 112, 114, 116 and 118, and a generally circular area 120 centered on each of them serves as a service area of each wireless base station. I have. By the way, the radio wave environment around the wireless base station is not always simple, and an enclave may occur in the service area due to the influence of terrain, terrain, and the like. In FIG. 3, an enclave 124 of the service area is formed far away from the service area 122 with respect to the original service area 122 of the wireless base station 102. If the radio base station 102 transmits only the service area 122, The electric field strength also becomes high at the enclave 124.
[0004]
If a mobile phone exists in such an enclave 124, the reception level of the radio wave from the peripheral base station reported by the mobile phone becomes the highest level of the reception of the radio wave from the radio base station 102. As a result, the radio base station A wireless channel is set to communicate through 102. However, the enclave 124 overlaps the service area of the wireless base stations 112 and 116, and radio waves are radiated from the wireless base stations 112 and 116 to the mobile phone at a high level. Since the radio base stations 112 and 116 are far from the radio base station 102, there is a possibility that the same frequency as that of the radio base stations 112 and 116 may be used. , 116, the noise is mixed in, the communication is interrupted, and good communication becomes difficult.
[0005]
When the mobile phone is moving, the mobile phone performs communication by switching the wireless base station by handover. Then, the next radio base station to be switched by handover is specified from the currently connected radio base station, and the radio base station 102 instructs the mobile phone to radio base stations 104, 106, 108 adjacent to the radio base station 102. Specifies a handover to one of If the mobile phone is within the original service area 122 of the wireless base station 102, this will result in a correct handover and allow the mobile phone to continue communication, but the mobile phone will remain in the enclave 124 as described above. If there is, even if switching to any of the wireless base stations 104, 106, and 108 as a result of the handover, communication becomes impossible because the mobile phone is outside the service area of these wireless base stations. I will.
[0006]
Conventionally, such a problem has been solved by changing (particularly lowering) the tilt of the antenna of the wireless base station 102 or changing to an antenna having different characteristics. However, changing the tilt of the antenna or replacing the antenna takes time and labor, and the shape of the service area changes. In some cases, it will.
[0007]
As one method for solving the problem of radio wave interference, Japanese Patent Laid-Open Publication No. Hei 7-2455776 discloses whether a channel can be allocated between a radio base station and a mobile phone based on a desired wave-to-interference ratio (CIR). A technique for determining is disclosed. However, even if this technology is used, if the CIR is good at the enclave of a certain service area, a radio channel is set between the enclave and a radio base station related to the same service area. Problems cannot be solved.
[0008]
The present invention has been made to solve such a problem, and an object of the present invention is to provide a mobile phone system in which noise is not mixed or communication is interrupted even when an enclave occurs in a service area of a radio base station. Is to provide.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a plurality of radio base stations and a plurality of mobile communication terminal devices, and the mobile communication terminal device is connected to a plurality of peripheral radio base stations at the time of outgoing / incoming call at the mobile communication terminal device. The station measures the reception level of the radio wave transmitted by each station and transmits a signal representing the measurement result to the radio base station, and the radio base station transmits and receives a control signal to and from the mobile communication terminal device and performs the mobile communication. A mobile phone system for designating a radio channel to the mobile communication terminal device based on the reception level notified from a terminal device, wherein the radio base station transmits and receives the control signal when the mobile communication terminal device makes and receives a call. Is transmitted to the mobile communication terminal device, and based on the time until the control signal is received from the mobile communication terminal device as a response, A distance measuring means for measuring a distance to a communication terminal device, and a radio base station transmitting a radio wave of a second highest reception level when the distance measured by the distance measuring means exceeds a reference value. Channel setting means for designating a wireless channel to the mobile communication terminal device so as to perform communication through the mobile communication terminal device.
[0010]
In the mobile phone system according to the present invention, the distance measuring means of the wireless base station transmits a control signal to the mobile phone at the time of outgoing / incoming call at the mobile phone and then, based on a time until a control signal is received from the mobile phone as a response thereto. To measure the distance to the mobile phone. When the distance measured by the distance measuring means exceeds the reference value, the channel setting means instructs the mobile phone to perform communication through the radio base station transmitting the radio wave of the second highest reception level. Specify a wireless channel.
[0011]
Therefore, even when the mobile phone is located in the enclave of the service area of a certain radio base station, the enclave is far from the radio base station, and the measurement result of the distance exceeds the reference value. Second, a wireless channel is set so as to perform communication through a wireless base station transmitting a radio wave of the second highest reception level, that is, a wireless base station in the vicinity of the base station.
Therefore, in the mobile phone system according to the present invention, even when an enclave occurs in the service area of the wireless base station, communication can be performed without intrusion of noise or communication interruption.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an example of a mobile phone system according to the present invention, and FIG. 2 is a schematic diagram showing a mobile phone system according to an embodiment.
As shown in FIGS. 1 and 2, the mobile phone system 2 of the present embodiment includes a plurality of wireless base stations 4 and a plurality of mobile phones 6. Numeral 6 measures the reception level of the radio wave transmitted by each of the plurality of peripheral wireless base stations 4 and transmits a signal indicating the measurement result to the wireless base station 4. And a wireless channel is designated to the mobile phone 6 based on the reception level notified from the mobile phone 6.
[0013]
In the present embodiment, the wireless base station 4 includes a distance measuring unit 10 and a channel setting unit 12 in the control unit 8.
The distance measuring means 10 transmits the control signal to the mobile phone 6 through the transmission / reception unit 9 and the amplifying unit 11 when the mobile phone 6 makes and receives a call. Then, the distance to the mobile phone 6 is measured based on the time until the reception.
When the distance measured by the distance measuring means 10 exceeds the reference value, the channel setting means 12 performs communication through the radio base station 4 transmitting the radio wave of the second highest reception level. A wireless channel is designated to the mobile phone 6.
In the present embodiment, the mobile phone system 2 is connected to a plurality of wireless base stations 4 through a transmission line network 14 and has a center station 16 having an exchange 19 connected to a public telephone network. Contains. The center station 16 is provided with a monitoring device 18 for supplying the reference value of the distance to the plurality of wireless base stations 4 for each wireless base station 4 via the transmission line network 14 in advance. The control unit 8 of each wireless base station 4 receives and holds this reference value.
[0014]
The distance measuring means 10 is provided with, for example, a capacitor and a constant current source, and starts charging the capacitor with the constant current source together with the transmission of the control signal to the mobile phone 6. , The charging of the capacitor by the constant current source is stopped, and the distance to the mobile phone 6 is obtained from the voltage of the capacitor at that time.
[0015]
The distance measuring means 10 is provided with a clock generator and a counter circuit, and starts counting the clock generated by the clock generator by the counter circuit together with the transmission of the control signal to the mobile phone 6. It is also possible to adopt a configuration in which the counting of the clock by the counter circuit is stopped together with the reception of the control signal from the counter 6 and the distance to the mobile phone 6 is obtained from the count value of the counter circuit at that time.
[0016]
Next, the operation of the mobile phone system 2 will be described.
When a call is received by the mobile phone 6 or when a call is transmitted from the mobile phone 6, the mobile phone 6 determines the reception level of radio waves from a plurality of wireless base stations 4 that can be received at the current position as a reception radio status report or a transmission radio status report. Report to the radio base station 4. Normally, the radio base station 4 controls the mobile phone 6 based on the radio status report so as to set a radio channel with the radio base station 4 transmitting the radio wave with the highest reception level to the mobile phone 6. Will do.
[0017]
However, in the mobile phone system 2 of the present embodiment, the wireless base station 4 specifies a wireless channel in consideration of the distance from the mobile phone 6 as well. When the mobile phone 6 makes and receives a call, the radio base station 4 receives the report of the reception level as described above, and sends and receives various control signals to and from the mobile phone 6. Transmitted to the mobile phone 6 for the authentication request, and the control signal transmitted by the mobile phone 6 to the wireless base station 4 for the authentication response.
[0018]
Then, the distance measuring means 10 of the wireless base station 4 transmits a control signal for an authentication request to the mobile phone 6 when the mobile phone 6 makes and receives a call, for example, and controls the authentication response from the mobile phone 6 as a response. The distance to the mobile phone 6 is measured based on the time until the signal is received. Note that the distance is obtained based on the time and the speed of light. However, since the time and the distance have a simple proportional relationship, the time data itself can be data representing the distance. Further, any value proportional to the time may be used as the data representing the distance.
[0019]
If the distance measured by the distance measuring means 10 is equal to or smaller than the reference value supplied from the monitoring device 18 in advance, the channel setting means 12 transmits the radio wave having the highest reception level to the mobile phone 6 as described above. The mobile phone 6 is controlled so as to set a wireless channel with the existing wireless base station 4. However, when the distance measured by the distance measuring means 10 exceeds the above-mentioned reference value, the mobile phone 6 transmits the radio signal to the radio base station 4 transmitting the radio wave of the second highest reception level. Specify a channel.
[0020]
Therefore, as shown in FIG. 3, even when the mobile phone 6 is located at the enclave 124 in the service area of the wireless base station 102, for example, the enclave 124 is far away from the wireless base station 102, so that the distance measurement result is Since the reference value is exceeded, the mobile phone 6 sets the radio channel so as to communicate through the radio base station transmitting the radio wave of the second highest reception level, that is, the radio base stations 112 and 116 in the original vicinity. Is set.
[0021]
Therefore, in the mobile phone system 2 according to the present embodiment, even when the enclave occurs in the service area of the wireless base station 4, the problem of radio wave interference and the problem that handover cannot be performed properly do not occur, and the noise does not occur. Communication can be performed without intrusion of communication or communication interruption.
[0022]
Further, in the present embodiment, since the reference value of the distance is set from the monitoring device 18 to each of the radio base stations 4, for example, the radio base stations 4 are added and the surrounding radio base stations 4 are set. In the case where the size of the service area changes, the monitoring device 18 can easily cope with the situation by sending a new reference value to each wireless base station 4.
However, it is not always necessary to provide a configuration in which the reference value is supplied from the monitoring device 18 to each wireless base station. For each wireless base station 4, the control unit 8 or the like individually stores and holds the distance reference value in advance. Of course, it is also possible to adopt a configuration in which it is set.
[0023]
【The invention's effect】
As described above, in the mobile phone system according to the present invention, the distance measuring means of the wireless base station transmits a control signal to the mobile phone at the time of outgoing / incoming call at the mobile phone, and then receives the control signal from the mobile phone as a response. Measure the distance to the mobile phone based on the time to. When the distance measured by the distance measuring means exceeds the reference value, the channel setting means instructs the mobile phone to perform communication through the radio base station transmitting the radio wave of the second highest reception level. Specify a wireless channel.
[0024]
Therefore, even when the mobile phone is located in the enclave of the service area of a certain radio base station, the enclave is far from the radio base station, and the measurement result of the distance exceeds the reference value. Second, a wireless channel is set so as to perform communication through a wireless base station transmitting a radio wave of the second highest reception level, that is, a wireless base station in the vicinity of the base station.
Therefore, in the mobile phone system according to the present invention, even when an enclave occurs in the service area of the wireless base station, communication can be performed without intrusion of noise or communication interruption.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of a mobile phone system according to the present invention.
FIG. 2 is a schematic diagram illustrating a mobile phone system according to an embodiment;
FIG. 3 is a schematic diagram showing a plurality of wireless base stations and respective service areas.
[Explanation of symbols]
2 ... mobile phone system, 4 ... wireless base station, 6 ... mobile phone, 8 ... control unit, 10 ... distance measuring means, 12 ... channel setting means, 14 ... transmission path network, 16 ... Center station, 18 monitoring device, 102 wireless base station, 104 wireless base station, 106 wireless base station, 108 wireless base station, 110 wireless base station, 112 wireless base station , 114... Wireless base station, 116... Wireless base station, 118... Wireless base station, 120... Area, 122... Service area, 124.

Claims (6)

A plurality of radio base stations, including a plurality of mobile communication terminal devices, at the time of outgoing and incoming calls in the mobile communication terminal device, the mobile communication terminal device receives the reception level of radio waves transmitted by the plurality of peripheral radio base stations respectively. Transmits a signal indicating the measurement result to the radio base station while measuring, and the radio base station transmits and receives a control signal between the mobile communication terminal device and the reception level notified from the mobile communication terminal device. A mobile phone system for designating a wireless channel to the mobile communication terminal device based on:
The wireless base station,
The mobile communication terminal device transmits the control signal to the mobile communication terminal device at the time of outgoing / incoming call at the mobile communication terminal device and then receives the control signal from the mobile communication terminal device as a response, based on the time. Distance measuring means for measuring the distance to,
If the distance measured by the distance measuring means exceeds a reference value, the mobile communication terminal device transmits a radio channel to the radio base station transmitting the radio wave of the second highest reception level. And a channel setting means for designating the mobile phone system. The mobile phone system according to claim 1, further comprising a monitoring device that supplies the reference value to each of the plurality of wireless base stations. 3. The monitoring apparatus according to claim 2, further comprising a center station connected to the plurality of wireless base stations through a transmission line network and connected to a public telephone communication network, wherein the monitoring device is installed in the center station. Mobile phone system as described. The control signal transmitted by the radio base station to the mobile communication terminal device is a control signal for an authentication request, and the control signal transmitted by the mobile communication terminal device to the radio base station is a control signal for an authentication response. The mobile phone system according to claim 1, wherein the mobile phone system is a signal. The distance measuring means includes a capacitor and a constant current source, and starts charging the capacitor with the constant current source together with the transmission of the control signal to the mobile communication terminal device. The charging of the capacitor by the constant current source is stopped at the same time as receiving the control signal, and the distance to the mobile communication terminal device is acquired by the voltage of the capacitor at that time. Mobile phone system. The distance measuring means includes a clock generator and a counter circuit, and starts counting the clock signal generated by the clock generator by the counter circuit together with the transmission of the control signal to the mobile communication terminal device. Stopping the counting of the clock signal by the counter circuit together with the reception of the control signal from the mobile communication terminal device, and acquiring the distance to the mobile communication terminal device from the count value of the counter circuit at that time. The mobile phone system according to claim 1, wherein:

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