JPH0865739A - Mobile communication system - Google Patents

Abstract

(57) [Abstract] [Purpose] To relocate the radio link frequency of a radio base station in a mobile communication service without using any special equipment and without manpower. In the wireless base station 18, the wireless base station reception signal processing unit 2 is assigned a communication line to be used for communication with a mobile terminal device 19 in a wireless zone of the wireless base station. When there is no communication, the electric field strength of the upstream radio wave 17 received through the communication line is monitored. Then, the radio base station control processing circuit 6 determines whether or not to continue the communication via the communication line by performing a predetermined statistical processing on the monitoring result, and if the communication is impossible, the communication is performed. Change the line to a call line of another frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system in which a mobile terminal device communicates with another person by performing radio communication via a radio base station.

[0002]

2. Description of the Related Art In mobile communication, a service area is covered by a plurality of radio base stations, and a mobile terminal device performs other radio communication by performing radio communication with a radio base station in a radio zone in which each mobile terminal device is located. Communicate with the person. The wireless communication in mobile communication is performed via a wireless line of a predetermined frequency, and the wireless line includes a call line and a control line. Of these, the call line is used by the mobile terminal to make an actual call or the like via the radio base station. Also,
The control line is a signal for the wireless base station to notify the mobile terminal device of the existence of the wireless zone, a signal for notifying an incoming call to the mobile terminal device in the service area, or a signal required for or before the mobile terminal device performs communication. It is used to transmit various control signals.

In mobile communication, effective use of frequencies, that is, how efficient are the limited types of frequencies permitted for use in mobile communication services for the communication lines and control lines of each radio base station? Is an important issue. In order to solve this problem, it is necessary to use the wireless line used in a certain wireless base station also in another wireless base station unless a particular problem occurs. However, since there are a plurality of radio base stations in the same space, there is a possibility that radio waves may interfere between the radio zones depending on the geographical relationship between the radio base stations using the same frequency. Therefore, it is necessary to consider the geographical relationship between the radio base stations when deciding the use frequency to be assigned to each radio base station so that such a problem does not occur. For example, in FIGS. 3 and 4, since the use frequencies of the base stations A and B are both f1, the radio zones of the base stations A and B overlap each other, that is, in the shaded area in FIG. Radio wave interference occurs between the wireless zones, which significantly deteriorates the communication quality, and in the worst case, communication may be disabled. In order to prevent such a problem, it is necessary to change the frequency of either the base station A or B to another frequency.

Further, even if the radio line frequencies are allocated to the respective radio base stations in consideration of the above, after that, the arrangement of the respective radio base stations is changed or the radio base stations are newly established. There are cases, etc. Further, the relationship between the number of wireless lines assigned to each wireless base station and the traffic to be handled by each wireless base station may be destroyed, and call loss may increase at some wireless base stations. In such a case, it is necessary to reallocate the wireless line to each wireless base station.

In the conventional mobile communication system, in order to deal with such a problem relating to the allocation of the radio frequency to the radio base station, a dedicated monitoring receiver is used or a radio base station for the mobile communication service. By suspending the operation of, the radio wave condition around each radio base station was monitored. In addition, each wireless base station is connected via a dedicated control line, and the traffic aggregated through the control line and the operating status of the wireless line are comprehensively managed by the control aggregation device. The method of artificially managing the radio frequency was adopted.

[0006]

As described above, the conventional mobile communication system requires a dedicated control line, a control aggregating device, and a monitoring receiving device in order to manage the radio line frequency of each radio base station. There was a problem that the cost increased. In addition, there is a problem that the wireless base station becomes large in size because the equipment such as the monitoring receiver must be installed in the wireless base station. Furthermore, when a new wireless base station is installed, the wireless line frequencies are artificially rearranged for each wireless base station, so it takes time for the wireless line frequency to be optimally arranged. was there.

The present invention has been made in view of the above-mentioned circumstances, and does not use special equipment for allocating the frequency of the radio line and does not require any manpower. It is an object of the present invention to provide a mobile communication system capable of rearranging frequencies.

[0008]

According to a first aspect of the present invention, a plurality of wireless base stations each configure a wireless zone, and a mobile terminal device moves within or between wireless zones, and the wireless terminal is present. In the mobile communication system for communicating with another person by performing wireless communication with the wireless base station of the zone, the wireless base station comprises: a. When the communication wireless line to be used for communication with the mobile terminal device in the wireless zone of the wireless base station is not assigned to the communication, it is received via the communication wireless line. Monitor the presence or absence of an up radio wave or the electric field strength, b. By performing a predetermined statistical process on the monitoring result, it is determined whether or not communication via the communication wireless line should be continued, c. A gist of a mobile communication system is characterized in that when the communication cannot be continued, the communication wireless line is changed to a communication wireless line of another frequency.

Further, the invention according to claim 2 is such that a plurality of radio base stations each configure a radio zone, and the mobile terminal device moves within or between the radio zones while the radio base station in the existing radio zone is present. In a mobile communication system for communicating with another person by performing wireless communication with a station, the wireless base station comprises: a. When the communication wireless line to be used for communication with the mobile terminal device in the wireless zone of the wireless base station is in the state where the communication wireless line is allocated for communication, the wireless base station is received via the communication wireless line. Measuring the quality of the upstream radio wave, b. By performing statistical processing using the correlation between the quality of the upstream radio wave and the electric field strength, the electric field strength of the upstream radio wave is calculated from the quality of the upstream radio wave obtained by the measurement, and the electric field of the upstream radio wave is calculated. Determining whether or not to continue communication via the communication wireless line based on the strength, c. A gist of a mobile communication system is characterized in that when the communication cannot be continued, the communication wireless line is changed to a communication wireless line of another frequency.

Further, the invention according to claim 3 is such that a plurality of radio base stations each configure a radio zone, and the mobile terminal device moves within or between the radio zones, and the radio base of the existing radio zone. In a mobile communication system for communicating with another person by performing wireless communication with a station, the mobile terminal device comprises: a. The quality or field strength of the downlink radio wave received from the radio base station via the communication radio line is measured, the measurement result is reported to the radio base station, and the radio base station b. A predetermined statistical process is performed on the measurement result reported by the mobile terminal device, and it is determined whether or not communication via the communication wireless line should be continued based on the result of the statistical process; c. A gist of a mobile communication system is characterized in that when the communication cannot be continued, the communication wireless line is changed to a communication wireless line of another frequency.

According to a fourth aspect of the present invention, a plurality of radio base stations each form a radio zone, and the mobile terminal device moves within or between the radio zones, and a radio base station in the existing radio zone is provided. In the mobile communication system for communicating with another person by performing the wireless communication of 1., each of the wireless base stations includes: a. Control information including station identification information of the own station is transmitted to the mobile terminal apparatus, and the station identification information is returned from each mobile terminal apparatus via a control wireless line; b. Among the signals received via the control wireless line, the occurrence status of signals not transmitted to the own station or whose signal contents are significantly deteriorated is monitored, and a predetermined statistical processing is performed on the monitoring result. And whether or not to continue the communication via the communication wireless line based on the result of the statistical processing, c. A gist of a mobile communication system is characterized in that when the control cannot be continued, the control wireless line is changed to a control wireless line of another frequency.

[0012]

According to the inventions according to claims 1 to 3, in response to a change in the communication environment such as the influence of radio waves from other wireless zones, the wireless base station communication wireless line is automatically operated as necessary. Is changed to. Further, according to the invention of claim 4, the control wireless line of the wireless base station is automatically changed in response to the change of the communication environment.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 illustrates a configuration of a radio base station and a mobile terminal device used in a mobile communication system according to the present embodiment. In this figure, 18 is a radio base station, and 19 is a mobile terminal device as a mobile station. The radio base station 18 forms a radio base station radio transmission / reception device 3 that transmits and receives radio waves with the mobile terminal device 19 via the antenna 4 and a signal to be transmitted via the radio base station radio transmission / reception device 3. The wireless base station transmission signal processing unit 1, the wireless base station reception signal processing unit 2 that performs processing such as decoding of a signal received via the wireless base station wireless transmission / reception device 3, and each unit in the wireless base station 18 are controlled. Wireless base station control processing circuit 6, a wireless base station storage circuit 7 used for storing control information, and the like, and a wireless base station control bus 5 provided as a signal transmission path between the above respective units. There is.

On the other hand, the mobile terminal device 19 basically has an antenna 8, a mobile terminal radio transmitting / receiving device 9, a mobile terminal transmission signal processing unit 10 and a mobile terminal reception signal, which play almost the same roles as the respective units in the radio base station 18. It comprises a processing unit 11, a mobile terminal control processing circuit 13, a mobile terminal storage circuit 14, and a mobile terminal control bus 12.

The above is the configuration of the radio base station and the mobile terminal device in the general mobile communication system. In this embodiment, the radio base station 18 is provided with a reception radio wave monitoring function unique to this embodiment and A line management function is provided, and these are used to control the communication line frequency described below.

First, the telephone line is managed as an idle telephone line by the radio base station control processing circuit 6 until a call is generated. However, when a call occurs and the call line is assigned to communication with the mobile terminal device 19, the call line is managed as being in use.

By the way, when the radio wave from another radio zone using the same frequency is received by the radio base station 18, the radio wave of the call line is received even though it is an idle call line. The Rukoto. Such an abnormal radio wave is called an idle communication line abnormal radio wave.

In this embodiment, it is determined whether or not the frequency of the currently used call line should be changed based on the occurrence condition of the abnormal call line abnormal radio wave. In order to monitor, the radio base station radio transmission / reception apparatus 3 has a reception radio wave monitoring function for obtaining the electric field strength of the reception signal of the call line not only during the period when the call line is in use but also in the state of the idle call line. . The electric field strength of the received signal obtained by the radio base station radio transmitter / receiver 3 is reported to the radio base station control processing circuit 6. The radio base station control processing circuit 6 determines whether or not an idle call line abnormal radio wave has been received based on the electric field strength of the received radio wave for the idle call line. Then, by using a statistical method, the state of the call line in the radio zone controlled by the radio base station 18 is recognized, and it is determined whether or not the service should be continued at the current call line frequency. Then, when it is determined that the continuation is impossible, a communication line frequency different from the current frequency is set based on the information about the spare frequency for the communication line stored in the wireless base station storage circuit 7. As the above statistical method, for example, by using the timer 15 in FIG. 1 together, the number of times of occurrence of an idle communication line abnormal radio wave is counted every unit time as shown in FIG. 2, and whether or not the count value is less than or equal to a predetermined threshold value. It is possible to use a method of determining whether or not the service can be continued depending on the situation.

<Second Embodiment> In the present embodiment, in FIG. 1, a function of measuring the quality of information such as an error occurrence of information received as an up radio wave 17 by the radio base station 18 during communication with the mobile terminal device 19. And the procedure is provided to the radio base station reception signal processing unit 2. The measurement result measured by this is called an upstream radio wave state during communication. Then, in the present embodiment, the correlation between the quality of the received signal and the electric field strength is used to obtain the electric field strength from the quality of the received signal, and a statistical method using the timer 15 is applied to this electric field strength. As a result, the state of the currently used communication line in the wireless zone controlled by the wireless base station 18 is recognized. Then, similarly to the first embodiment, it is determined whether or not the service should be continued at the current telephone line frequency based on the recognition result,
Change control of the telephone line frequency is performed based on this determination result.

<Third Embodiment> In this embodiment, in FIG. 1, the electric field value of the downlink radio wave 16 received by the mobile terminal device 19 during the communication with the radio base station 18, the error occurrence of the received information, etc. The mobile terminal reception signal processing unit 11 is provided with a function and a procedure for measuring the quality of. The measurement result measured by this is called a downlink radio wave state during communication. Then, in this embodiment, the mobile terminal device 19 reports the downlink radio wave state during communication to the radio base station 18. The radio base station 18 applies the statistical method using the timer 15 to the reported downlink radio wave state during communication, thereby
8 recognizes the state of the telephone line currently in use within the wireless zone under the control of 8. And, like the first embodiment,
Based on this recognition result, it is determined whether or not the service should be continued at the current communication line frequency, and the change control of the communication line frequency is performed based on this determination result.

<Fourth Embodiment> In this embodiment, the radio base station transmission signal processing unit 1 in FIG.
It has a function and a procedure of inserting station identification information for identifying the wireless base station 18 into the notification information for notifying the mobile terminal device 19 of the wireless zone of 1. Then, the radio base station 18 transmits the broadcast information in which the station identification information is inserted in this way to the mobile terminal device 19 via the downlink control line, and the transmitted station identification information is stored in the radio base station storage circuit 7. Remember.

On the other hand, the mobile terminal reception signal processing unit 11 in the mobile terminal device 19 has a function and means for recognizing the station identification information in the broadcast information received from the radio base station 18. Further, the mobile terminal control processing circuit 13 causes the mobile terminal storage circuit 7 to store the station identification information recognized by the mobile terminal reception signal processing unit 11. Therefore, the station identification information in the mobile terminal storage circuit 7 is updated with the station identification information received in the new wireless zone every time the wireless zone in which the mobile terminal device 19 is located changes. The mobile terminal transmission signal processing unit 10 also has a function and means for adding the station identification information received from the wireless base station 18 to the transmission signal. The transmission signal to which the station identification information is added is transmitted to the wireless base station 18 via the control line.

The radio base station 18 has the following functions and means for performing processing based on the station identification information thus returned.

First, the radio base station reception signal processing unit 2 recognizes the station identification information included in the reception signal, and the station identification information and the station identification information which is currently being emitted and is stored in the radio base station storage circuit 7. It has a function and means for determining whether or not the received signal is a signal transmitted to the wireless base station 18 by collating with. Radio base station reception signal processing unit 2
If the received signal is a signal transmitted from the mobile terminal device in the wireless zone of the own station to the own station, the received signal is processed based on the determination result. On the other hand, when the received signal is not for the own station, that is, the radio base station 1
If the signal is emitted from another wireless zone using the same frequency as the wireless zone of 8, the received signal is rejected.

Further, the radio base station reception signal processing unit 2 has a function and means for judging that the reception signal is in the following states. a. When the signal is received from another wireless zone b. Although it is a signal received from the wireless zone of its own station, its quality has deteriorated due to mutual interference and the like, and information other than the station identification information of its own station is additionally inserted. A state in which the judgments of a and b above cannot be made. That is, the state of the received signal is extremely poor and does not make sense as information.

The received signal corresponding to the above is called a control line abnormal radio wave. The radio base station control processing circuit 6 obtains the time density at which abnormal radio waves in the control line are generated by performing statistical processing using the timer 15. Then, based on this result, it is determined whether or not the service using the current control line should be continued. If it is determined that the service cannot be continued, the control line is changed to another frequency.

Now, in the above, the transmission signal is divided into specific units, and each unit signal added with the station identification information is shifted on the time axis and sequentially transmitted from the radio base station 18 to the mobile terminal device 19. A communication form in which each mobile terminal device 19 sequentially returns to the radio base station 18 is also conceivable. In this case, if the radio base station reception signal processing unit 2 is configured to detect the following abnormalities in addition to the above a, b, and c, it is more severely evaluated whether or not the service by the current control line should be continued. can do. d. Abnormalities in which the unit signals are not returned in the prescribed order. E. Abnormality in which part of each unit signal is not received in a normal state f. Continuous information consisting of each unit signal is received,
The station identification information added to some unit signals is different from that of other unit signals.

<Other Embodiments> The evaluation as to whether or not the current line should be continued is not performed by using each of the methods described in the first to fourth embodiments alone, but It is also possible to use two or more methods in combination and judge whether or not to continue by comprehensively judging the evaluation results using each method.

[0029]

According to the present invention described above, the wireless base station or the mobile terminal device autonomously responds to a change in the communication environment such as an influence from another wireless zone, thereby allowing the wireless base station to perform wireless communication. Since the line frequency is rearranged, there is an effect that the equipment and cost required for the rearrangement can be reduced, and that it is possible to promptly respond to environmental changes such as new installation of a wireless base station.

[Brief description of drawings]

FIG. 1 is a diagram illustrating configurations of a radio base station and a mobile terminal device to which a mobile communication system according to the present invention is applied.

FIG. 2 is a diagram illustrating a change control of a telephone line frequency in the embodiment of the present invention.

FIG. 3 is a diagram illustrating interference between wireless zones.

FIG. 4 is a diagram illustrating interference between wireless zones.

[Explanation of Codes] 18 ... Radio base station, 1 ... Radio base station transmission signal processing unit, 2 ... Radio base station reception signal processing unit, 3 ... Radio base station radio transmission / reception processing unit, 6 ... Radio base Station control processing circuit,
7 ... Radio base station memory circuit, 19 ... Mobile terminal device, 10
...... Mobile terminal transmission signal processing unit, 11 ...... Mobile terminal reception signal processing unit, 9 ...... Mobile terminal wireless transmission / reception processing unit, 13 ......
Mobile terminal control processing circuit, 14 ... Mobile terminal storage circuit, 17
...... Up radio wave, 16 …… Down radio wave.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoto Nagata 2-10-1 Toranomon, Minato-ku, Tokyo NTT Mobile Communications Network Co., Ltd.

Claims (4)

[Claims] 1. A plurality of radio base stations each configure a radio zone, and a mobile terminal device performs radio communication with a radio base station in a radio zone in which the mobile terminal device moves while moving within or between the radio zones. In the mobile communication system for communicating with another person according to, the radio base station comprises: a. When the communication wireless line to be used for communication with the mobile terminal device in the wireless zone of the wireless base station is not assigned to the communication, it is received via the communication wireless line. Monitor the presence or absence of an up radio wave or the electric field strength, b. By performing a predetermined statistical process on the monitoring result, it is determined whether or not communication via the communication wireless line should be continued, c. A mobile communication system, wherein the communication wireless line is changed to a communication wireless line of another frequency when the communication cannot be continued. 2. A plurality of radio base stations each configure a radio zone, and a mobile terminal device performs radio communication with a radio base station in a radio zone in which the mobile terminal device moves while moving between radio zones or between radio zones. In the mobile communication system for communicating with another person according to, the radio base station comprises: a. When the communication wireless line to be used for communication with the mobile terminal device in the wireless zone of the wireless base station is in the state where the communication wireless line is allocated for communication, the wireless base station is received via the communication wireless line. Measuring the quality of the upstream radio wave, b. By performing statistical processing using the correlation between the quality of the upstream radio wave and the electric field strength, the electric field strength of the upstream radio wave is calculated from the quality of the upstream radio wave obtained by the measurement, and the electric field of the upstream radio wave is calculated. Determining whether or not to continue communication via the communication wireless line based on the strength, c. A mobile communication system, wherein the communication wireless line is changed to a communication wireless line of another frequency when the communication cannot be continued. 3. A plurality of wireless base stations each configure a wireless zone, and a mobile terminal device performs wireless communication with a wireless base station in a wireless zone in which the mobile terminal device moves while moving within or between wireless zones. In the mobile communication system for communicating with another person according to, the mobile terminal device comprises: a. The quality or field strength of the downlink radio wave received from the radio base station via the communication radio line is measured, the measurement result is reported to the radio base station, and the radio base station b. A predetermined statistical process is performed on the measurement result reported by the mobile terminal device, and it is determined whether or not communication via the communication wireless line should be continued based on the result of the statistical process; c. A mobile communication system, wherein the communication wireless line is changed to a communication wireless line of another frequency when the communication cannot be continued. 4. A plurality of wireless base stations each configure a wireless zone, and a mobile terminal device performs wireless communication with a wireless base station in a wireless zone in which the mobile terminal device moves while moving between wireless zones or between wireless zones. In the mobile communication system for communicating with another person according to, each of the radio base stations includes: a. Control information including station identification information of the own station is transmitted to the mobile terminal apparatus, and the station identification information is returned from each mobile terminal apparatus via a control wireless line; b. Among the signals received via the control wireless line, the occurrence status of signals not transmitted to the own station or whose signal contents are significantly deteriorated is monitored, and a predetermined statistical processing is performed on the monitoring result. And whether or not to continue the communication via the communication wireless line based on the result of the statistical processing, c. A mobile communication system, wherein the control radio line is changed to a control radio line of another frequency when it is impossible to continue.