JPH1065596A - Transmission output control method for mobile communication system and mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control optimizingly a transmission output of a radio base station or a mobile equipment in rainfall in a mobile communication system. SOLUTION: When a rainfall sensor 26 senses rainfall, it is sent to a transmission output control section 22. Furthermore, a GPS antenna 27, a GPS reception section 20 and an error detection section 21 receive a GPS radio wave to detect the error and it is sent to the transmission output control section 22. The transmission output control section 22 calculates a rainfall attenuation of a radio wave based on the error and an output signal of the rainfall sensor 26 and calculates an optimum transmission output for radio base stations 11, 12 and a mobile equipment 10. The transmission output control section 22 controls the transmission output of the radio base stations 11, 12 to the calculated transmission output value and uses the transmission output of the mobile equipment 10 to be data, which are sent to a transmission output control section 29 of the mobile equipment 10. The transmission output control section 29 of the mobile equipment 10 uses the data to control the transmission output of the mobile equipment 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio base station and a transmission power control method for a mobile station in a mobile communication system.

[0002]

2. Description of the Related Art Conventionally, a transmission output control method in this type of mobile communication system is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 61-4302.
As shown in FIG. 6, a means for detecting the reception level and increasing or decreasing the transmission output in accordance with the value of the reception level is provided in the radio transceiver of the radio base station or the mobile station. The output is controlled so that the output is high and the transmission output is low when the reception level is high.

[0003] The same content as described above is published in the publication "Digital Mobile Communication" published by Kagaku Shimbun. This is described in the item of transmission power control on page 151, and indicates that there is a feedback type in which the mobile station side transmission power is determined based on the reception result at the radio base station side as a normal method.

FIG. 8 is a block diagram of a conventional mobile communication system. The wireless base station 65 receives the radio wave of the uplink control channel 66 from the mobile device 64 and detects the electric field strength at the receiving unit of the wireless transmitting / receiving unit 62 of the wireless base station 65. The transmission output value of the mobile station according to the electric field strength is transmitted to the radio base station 6.
5 is determined by the wireless transmission / reception unit 62. The determined value is transmitted from the transmission unit of the wireless transmission / reception unit 62 to the mobile device 64 via the wireless common amplification unit 61. The mobile device 64 receives the downlink control channel 67, which is a transmission radio wave, and extracts the mobile device transmission output value from the received signal by the wireless transmission / reception unit 60 of the mobile device 64. The transmission output of the mobile device 64 is controlled based on the extracted mobile device transmission output value.

[0005]

The above-mentioned conventional transmission power control method for a mobile communication system has the following problems. (1) In the conventional technique, a control channel transmitted from a mobile device is received by a wireless base station, and a transmission output is determined according to the electric field strength. Even if the received electric field strength is lowered during a call or during a call, this method has no problem if the received electric field strength for establishing a call with a wireless base station or a mobile device can be ensured. However, in the high frequency band of 1.9 GHz or higher used in mobile communication systems in the future, if the radio wave is greatly attenuated due to sudden rainfall and a call cannot be established between a radio base station and a mobile device, a call can be made. During a call, the call is disconnected. (2) Further, when a radio channel is designed in consideration of rain attenuation while keeping the transmission output as it is, a problem of reducing the service area occurs. Conversely, when a wireless channel is designed in consideration of rainfall attenuation while securing a service area, the transmission output of the radio base station and the mobile station must be uniformly increased by the rainfall attenuation. Increasing the transmission output causes a problem of radio wave interference in the base station, and also increases the load on the battery in the mobile device and shortens the usable time of the battery.

An object of the present invention is to provide a transmission output control method for a mobile communication system and a mobile communication system that optimally control the transmission output of a radio base station or a mobile station during rainfall.

[0007]

To achieve the above object, a transmission power control method for a mobile communication system according to the present invention comprises:
The transmission output of at least one of the radio base station and the mobile station is optimally controlled according to the rain attenuation.

According to the embodiment of the present invention, the transmission output of at least one of the radio base station and the mobile station is increased according to the rain attenuation only during the rain phenomenon, and the transmission is performed when the rain phenomenon disappears. Undo the output.

[0009] Thereby, the transmission output of at least one of the radio base station and the mobile station can be reduced to a necessary minimum output.

Further, in the mobile communication system of the present invention, the radio base station detects the presence or absence of rain by using a rain sensor and a GPS (Global Positioning) signal from a satellite.
System) GPS antenna for receiving radio waves, GP
A GPS receiver for demodulating the S radio wave, an error detector for detecting an error of the GPS radio wave from the signal demodulated by the GPS receiver and the position of the radio base station, and an output signal of the rain sensor and detected by the error detector. A transmission output control unit for estimating rainfall from the error and determining an optimal transmission output.

The present invention estimates a rainfall amount and a rain attenuation amount in a wireless area of a wireless base station based on a rainfall sensor and an error of a GPS radio wave proportional to the amount of water vapor in the atmosphere, and according to the rainfall attenuation amount. This is for optimally controlling the transmission output of the radio base station. Therefore, the communication quality can be ensured with the minimum necessary transmission output.

According to the embodiment of the present invention, the mobile device receives the optimum transmission output value determined by the transmission output control unit based on the amount of rainfall, and controls the transmission output based on the transmission output value.

According to the present invention, control is performed not only for the radio base station but also for the transmission output of the mobile station in accordance with the amount of rain attenuation. Therefore, the power load on the battery of the mobile device can be minimized.

According to another embodiment of the present invention, when the rainfall sensor does not detect rainfall, the transmission output control section controls the G output.
The optimum transmission output is determined only by the error of the PS radio wave.

According to another embodiment of the present invention, when GPS radio waves cannot be received, the transmission output control unit determines an optimum transmission output only from the output signal of the rain sensor.

Further, in the mobile communication system of the present invention, the radio base station receives a rainfall sensor for detecting the presence or absence of rainfall and the latest rainfall information of a local meteorological observation system (AMeDAS system) of the Japan Meteorological Agency, and receives the rainfall information. And a transmission output control unit for estimating rain attenuation of the radio base station from the above, and determining an optimum transmission output.

The present invention estimates rainfall and rainfall attenuation in a wireless area of a wireless base station based on rainfall information of a rain sensor and an AMeDAS system, and optimizes the transmission output of the wireless base station according to the rainfall attenuation. To control. Therefore, the communication quality can be ensured with the minimum necessary transmission output.

According to the embodiment of the present invention, the mobile device receives the optimum transmission output value determined by the transmission output control section and controls the transmission output based on the transmission output value.

The present invention controls the transmission output of not only the radio base station but also the mobile station in accordance with the rain attenuation. Therefore, the power load on the battery of the mobile device can be minimized.

According to another embodiment of the present invention, when a rainfall sensor does not detect rainfall, the transmission output control unit determines an optimum transmission output only from rainfall information sent from the AMeDAS system. .

According to another embodiment of the present invention, when the rainfall information sent from the AMeDAS system cannot be received, the transmission output control unit determines the optimum transmission output only by the output signal of the rainfall sensor. I do.

[0022]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a configuration diagram of a mobile communication system according to a first embodiment of the present invention.

The mobile communication system of this embodiment, the mobile station 10, the radio base station 11 to the wireless area L ₁ and wireless area, the radio base station 12 to the wireless area L ₂ and wireless area, the radio base station 11, 12 and transmission paths 14,
It is composed of a radio base station controller 13 connected at 15. In this case, the mobile station 10 is present in the wireless area L _1, the radio network with the radio frequency f ₁ and f ₂ between the mobile station 10 and the radio base station 11 is configured.

FIG. 2 shows the radio base stations 11 and 12 and the mobile station 10 in FIG. 1, and FIG. 3 shows the radio base stations 11 and 12
FIG. 5 is a configuration diagram of a downlink control channel transmitted for 0. The radio base stations 11 and 12 are provided with a rain sensor 26 and a GP.
S antenna 27, GPS receiver 20, error detector 2
1, a transmission output control unit 22, a wireless common amplification unit 23,
It comprises a wireless transmission / reception unit 24 and a line multiplex transmission unit 25. The mobile device 10 includes a wireless transmission / reception unit 28 and a transmission output control unit 29.

First, the GPS will be described. , The GPS antenna 27, the GPS receiver 20, and the error detector 21 detect the arrival time difference of the GPS reception radio wave in order to measure the amount of water vapor contained in the atmosphere. When the GPS system simultaneously receives radio waves emitted by four or more satellites out of a constellation of satellites orbiting at a height of about 20,000 km, the position of the received point,
It is a system that measures high absolute values. Therefore, if the amount of water vapor contained in the atmosphere from the satellite to the receiving point is large, it takes time to reach the radio wave, and the vertical error is several c.
It occurs in m units. The actual distribution of water vapor in the atmosphere is spatially non-uniform and changes over time. In a few days, the ground is not moving at all. Then, on the contrary, the amount of water vapor above the receiving point can be calculated from the difference in the arrival time of the radio wave.

Next, the operation of the present embodiment will be described with reference to the drawings. The wireless base station 11 at the fixed position and the mobile device 10 mutually perform transmission / reception operations using the radio frequencies f ₁ and f ₂ . At this time, the mobile station 10 is moved in a timely manner, and the radio line is greatly affected by the state change of the radio channel. In particular, in a high frequency band of 1.9 GHz or more used in a mobile communication system in the future, the amount of rain attenuation cannot be ignored, and it is necessary to control the transmission output of the radio base station 11 and the mobile device 10 according to the rain state.

A GPS radio wave is received by the GPS antenna 27 and the GPS reception unit 20, and this signal is input to an error detection unit 21 which detects a difference in arrival time of the radio wave included in the reception signal. The error of the GPS radio wave output from the error detector 21 is input to the transmission output controller 22 together with the output of the rain sensor 26 for detecting the presence or absence of rain. Transmission output control unit 22
When the rain sensor 26 detects rain, the G
It outputs a transmission output control signal for controlling to increase the transmission output of the radio base stations 11, 12 and the mobile station 10 by an error of the PS radio wave. This transmission output control signal is transmitted to the radio
4 and the base station transmission output is varied by the wireless common amplification unit 23. Further, the transmission power control signal is inserted into the downlink control channel transmitted from the radio base stations 11 and 12 to the mobile device 10 as shown in FIG. Sent.

The mobile station transmission output control signal received by mobile station 10 is received by radio transmitting / receiving section 28 of mobile station 10,
It is input to the transmission output control unit 29. Transmission output control unit 29
Sends a signal for controlling the transmission output of the mobile device 10 to the wireless transmission / reception unit 28 according to the input transmission output control signal, and varies the transmission output of the mobile device.

FIG. 4 shows an operation in which the transmission output control unit 22 controls the transmission output of the radio base stations 11 and 12 and the mobile unit 10 based on the output signal of the rain sensor 26 and the error obtained from the error detection unit 21. It is a flowchart shown. First,
As an initial state, the transmission output value of each of the radio base stations 11, 12 and the mobile device 10 is set to an initial value (reference value) (step 4).
0). This is the transmission output value when there is no attenuation due to rainfall. Next, it is determined whether the GPS radio wave has been received (step 41). If the GPS radio wave can be received, an error of the received GPS radio wave is detected (step 42).
Then, a transmission output value corresponding to the error value is calculated (step 43). Next, it is determined whether the rainfall sensor 26 has detected rainfall (step 44). When rainfall is detected, a fixed value A is further added to the calculated transmission output value (step 45). Then, the final transmission output value is notified to the wireless transmission / reception unit 24 (step 46). Thereby, the wireless common amplification unit 23 transmits the transmission output value to the mobile device 10 with the transmission output value.

If no GPS radio wave can be received in step 41, it is determined whether the rain sensor 26 has detected rain (step 47). When rainfall is detected by the rainfall sensor 26, the fixed value B is added to the transmission output value (step 48), and the process of step 46 is performed.

The fixed value A at step 45 is smaller than the fixed value B at step 48.

In the mobile station 10, the transmission output value of the mobile station is extracted by the transmission output control section 29 and transmitted to the radio transmission / reception section 28, whereby the transmission output of the mobile station 10 is controlled.

FIG. 5 shows the radio base stations 11 and 12 and the mobile station 10.
FIG. 4 is a communication sequence diagram regarding transmission output control of FIG.

First, as the first state, the radio base station 11,
The transmission device 12 and the mobile device 10 use the transmission output values they have as initial values. Here, the radio base stations 11 and 12 are G
When rain is detected by the PS radio wave or the rain sensor 26 and the transmission output value is changed, first, the radio base stations 11 and 12 use the transmission output value and transmit it to the mobile device 10 as broadcast information (step 50). The mobile device 10 receives the broadcast information, stores the transmission output value contained therein, and uses the transmission output value (step 51). Further, when the radio base stations 11 and 12 detect that the rain has stopped by the GPS radio wave or the rain sensor 26 and return the transmission output value to the original initial value, the radio base station 1
1 and 12 use the transmission output of the initial value and transmit it to the mobile device 10 as broadcast information (step 5).
2). The mobile device 10 receives the notification information, extracts the transmission output value contained therein, and restores the transmission output (step 53).

(Second Embodiment) FIG. 6 is a block diagram of a mobile communication system according to a second embodiment of the present invention, and FIG. 7 is a block diagram of the radio base stations 71 and 71 and the mobile station 10 in FIG. It is. The same numbers as those in FIG. 1 indicate the same components.

The mobile communication system of this embodiment, the mobile station 10, the radio base station 71 to the wireless area L ₁ and wireless area, the radio base station 72 to the wireless area L ₂ and wireless area, the radio base station 71, 72 and transmission lines 14,
The wireless base station controller 13 connected at 15, a rain gauge 36 installed in various parts of Japan to measure rainfall data at the installed location, a public transmission line 35, and a Meteorological Agency installed to control the AMeDAS system It is composed of the Meteorological Agency AMeDAS system computer system 31, the Japan Meteorological Association computer system 30, and a mobile communication exchange 34 for distributing rainfall data to the radio base station controller 13. The public transmission line 35 transmits the rainfall data of the rain gauge 36 to the Meteorological Agency AMeDAS system computer system 31 via a dedicated line or a telephone line.

In this system, the mobile station 10 exists in the radio area L ₁ , and a radio line is formed between the mobile station 10 and the radio base station 71 using the radio frequencies f ₁ and f ₂ .

First, the outline of the AMeDAS system of the Meteorological Agency will be described. Currently, there are about 1,300 AMeDAS system observation points nationwide, and at each observation point, a rain gauge 36 is installed to observe rainfall.
At zero locations, in addition to rainfall, temperature, wind direction, wind speed, and daylight hours are also observed. In addition, about 2 around the heavy snowfall area of the whole country
We also measure snowfall at 10 locations. The national average is that there is one observation point for rainfall at 17 km square, and the number of observation points will continue to increase in order to improve the accuracy of local meteorological observations.

Next, the operation of this embodiment will be described with reference to the drawings. The wireless base station 71 at the fixed position and the mobile device 10 mutually perform transmission / reception operations using the radio frequencies f ₁ and f ₂ . At this time, the mobile station 10 is moved in a timely manner, and the radio line is greatly affected by the state change of the radio channel. In particular, in a high frequency band of 1.9 GHz or higher that will be used in the future, the amount of rain attenuation cannot be ignored, and it is necessary to control the transmission output of the radio base station 71 and the mobile device 10 according to the rain state.

The rainfall data observed by the rain gauges 36 in various places is periodically sent to the Meteorological Agency AMeDAS system computer system 31 installed at the Meteorological Agency in Tokyo via the public transmission line 35. The Meteorological Agency AMeDAS system The computer system 31 automatically checks the contents of the rainfall data sent for abnormal values, etc., and then temporarily sends the rainfall data to the Japan Meteorological Agency's C-ADESS, a national central weather data automatic editing and relay device. At the same time, it is also delivered to the Japan Meteorological Association computer system 30 installed at the Japan Meteorological Association (hereinafter referred to as the Japan Meteorological Association), which is developing general use of weather data.
The Japan Meteorological Association computer system 30 collects and analyzes the distributed data and information and provides the data and information to the mobile communication system as rainfall information announced by the Japan Meteorological Association. The provided rainfall information is input to the mobile switching center 34 and transmitted to the radio base station controller 13 by the mobile switching center 34. The radio base station controller 13 transmits the received rainfall information to the radio base stations 71 and 72, respectively.

This rainfall information is composed of numerical data including grid point data and various character data, and is divided into a current rainfall situation and a future rainfall forecast situation. In the present embodiment, only the current rainfall situation is used.

In the radio base station 71, both the data of the rain sensor 26 and the rain information sent from the AMeDAS system via the line multiplex transmission unit 25 are input to the transmission output control unit 22.

The transmission output control unit 22 analyzes the rainfall information of the rainfall sensor 26 and the AMeDAS system, estimates the rainfall attenuation in the service area of the radio base station 71,
It outputs a transmission output control signal for controlling to increase the transmission output of the radio base station 71 and the mobile device 10 by the amount of rain attenuation. This transmission output control signal is input to the wireless transmission / reception unit 24, and the wireless common amplification unit 23 varies the base station transmission output.
Further, the transmission output control signal is transmitted from the radio base station 71 to the mobile station 1.
0 is transmitted to the mobile station 10 as a mobile station transmission output control signal that is inserted into the control channel of the downlink radio channel to be transmitted. The mobile station 10 controls the transmission output according to the transmitted mobile station transmission output control signal in the same manner as in the first embodiment.

The mobile station 10 and the radio base stations 71 and 72
The transmission output control method of the first embodiment is different from the method shown in the flowchart of FIG. 4 of the first embodiment and the communication sequence diagram of FIG. 5 in that the detection of rainfall by GPS is replaced by the detection of rainfall by AMeDAS system. It is done in a similar way.

[0046]

As described above, the present invention has the following effects. (1) A rainfall sensor that detects the presence or absence of rainfall, and a rainfall amount detection unit and a fine transmission output control are performed to correct rainfall attenuation in radio waves in a high frequency band used in a mobile communication system, and to reduce rainfall. Problems such as the reduction of the service area of the mobile communication system and the disconnection of a call during a call are solved and the call quality is ensured. (2) Increasing the transmission output of at least one of the radio base station and the mobile device in accordance with the amount of rain attenuation generated in proportion to the amount of water vapor contained in the atmosphere during rainfall, The problem of radio interference caused by transmission radio waves (same radio interference due to repeated use, interference due to intermodulation, etc.) can be minimized, and the power load on the battery of the mobile device can be minimized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a mobile communication system according to a first embodiment of the present invention.

FIG. 2 is a block diagram of the radio base stations 11 and 12 and the mobile device 10 in FIG.

FIG. 3 is a configuration diagram of a downlink control channel transmitted from the radio base stations 11 and 12 to the mobile device 10.

FIG. 4 is a flowchart showing transmission output control.

FIG. 5 is a communication sequence diagram relating to transmission output control of the radio base stations 11 and 12 and the mobile device 10.

FIG. 6 is a configuration diagram of a mobile communication system according to a second embodiment of the present invention.

FIG. 7 is a block diagram of the radio base stations 71 and 72 and the mobile device 10 in FIG.

FIG. 8 is a block diagram of a conventional mobile communication system.

[Explanation of symbols]

Reference Signs List 10 mobile station 11 radio base station 12 radio base station 13 radio base station controller 14 transmission line 15 transmission line f ₁ , f ₂ radio frequency L ₁ , L ₂ radio area 20 GPS receiver 21 error detector 22 transmission output controller Reference Signs List 23 wireless common amplification unit 24 wireless transmission / reception unit 25 line multiplex transmission unit 26 rain sensor 27 GPS antenna 28 wireless transmission / reception unit 29 transmission output control unit 30 Japan Meteorological Association computer system 31 Japan Meteorological Agency AMeDAS system computer system 34 mobile communication switching station 35 public transmission line 36 rain gauge 40-48 step 50-53 step 60 radio transmission / reception unit 61 radio common amplification unit 62 radio transmission / reception unit 63 line multiplex transmission unit 64 mobile station 65 radio base station 66 control channel (up) 67 control channel (down) 71 radio Base station 72 Wireless base station

Claims (10)

[Claims] 1. A transmission output control method for a mobile communication system, wherein the transmission output of at least one of a radio base station and a mobile station is optimally controlled according to its rain attenuation. Transmission output control method. 2. While the rain phenomenon is occurring, the transmission output of at least one of the radio base station and the mobile station is increased according to the rain attenuation, and when the rain phenomenon disappears, the transmission output is restored. Item 4. The transmission output control method according to Item 1. 3. In a mobile communication system having a radio base station, the radio base station includes a rain sensor for detecting the presence or absence of rain, a GPS antenna for receiving a GPS radio wave from a satellite, and a GPS for demodulating the GPS radio wave. A receiver, an error detector for detecting an error of a GPS radio wave from a signal demodulated by the GPS receiver and a position of the wireless base station;
A mobile communication system, comprising: a transmission output control unit that estimates rain attenuation from an output signal of the rain sensor and an error detected by the error detection unit and determines an optimal transmission output. 4. The mobile communication system according to claim 3, wherein the mobile device receives an optimal transmission output value determined by the transmission output control unit, and controls the transmission output based on the transmission output value. 5. When the rainfall sensor does not detect rainfall, the transmission output control unit outputs an optimal transmission output to the GP.
The mobile communication system according to claim 3, wherein the mobile communication system is determined only by an error of the S radio wave. 6. The mobile communication system according to claim 3, wherein, when the GPS radio wave cannot be received, the transmission output control unit determines an optimum transmission output only from an output signal of the rain sensor. 7. In a mobile communication system having a radio base station, the radio base station receives a rainfall sensor for detecting the presence or absence of rainfall and the latest rainfall information of a local meteorological observation system (AMeDAS system) of the Japan Meteorological Agency. A mobile communication system comprising: a transmission output control unit that estimates a rain attenuation of the radio base station from the rain information and determines an optimal transmission output. 8. The mobile communication system according to claim 7, wherein the mobile device receives an optimal transmission output value determined by the transmission output control unit, and controls the transmission output based on the transmission output value. 9. The mobile communication according to claim 7, wherein when the rainfall sensor does not detect rainfall, the transmission output control unit determines an optimum transmission output only from rainfall information sent from the AMeDAS system. system. 10. The movement according to claim 7, wherein when the rainfall information sent from the AMeDAS system cannot be received, the transmission output control unit determines an optimum transmission output only by an output signal of the rainfall sensor. Communications system.