JP6158741B2 - COMMUNICATION TERMINAL, RADIO COMMUNICATION SYSTEM, MOBILE COMMUNICATION METHOD, AND MOBILE COMMUNICATION PROGRAM - Google Patents

Description

  The present invention relates to a communication terminal, a wireless communication system, a mobile communication method, and a mobile communication program that stably communicate with a radio base station.

  A PHS (Personal Handy-phone System) communication terminal is used for a telemetering system for managing the usage of electric power, gas, water, and the like, and for communication via a wireless base station inside and outside a building of a general household. In communication via a radio base station, when the radio wave received from the radio base station is too strong, too weak, or greatly changes, communication with the radio base station becomes unstable.

  FIG. 10 and FIG. 11 are explanatory diagrams showing the relationship between the use location where the communication terminal 101 of PHS is used and the radio base station 201. In the example shown in FIG. 10A, an automobile or the like passes between the wireless base station 201 and the place of use. Then, fading occurs in the radio wave emitted by the radio base station 201 in accordance with the passage of the automobile or the like, and the electric field strength of the radio wave received by the communication terminal 101 changes, resulting in unstable communication.

  In the example shown in FIG. 10B, an iron wall having unevenness is provided between the radio base station 201 and the place of use. Then, due to the unevenness or the like, fading occurs in the radio wave emitted from the radio base station 201, and the electric field intensity of the radio wave received by the communication terminal 101 changes to make communication unstable.

  In the example illustrated in FIG. 11, the distance between the radio base stations 201 a to 201 c and the place of use is short. Then, the electric field strength of the radio wave received by the communication terminal 101 from the radio base stations 201a to 201c becomes larger than the upper limit of the appropriate range of the received electric field strength according to the PHS standard, and the communication terminal 101 and the radio base stations 201a to 201c. Communication with 201c becomes unstable. In the example shown in FIG. 11, the distance between the radio base station 201d and the place of use is long. Then, the electric field strength of the radio wave received by the communication terminal 101 from the radio base station 201d is smaller than the lower limit of the range of the appropriate reception electric field strength according to the PHS standard, and between the communication terminal 101 and the radio base station 201d. Communication becomes unstable.

  The PHS communication terminal 101 is preferably subjected to maintenance for adjusting the setting according to the place of use. However, the maintenance work of the PHS communication terminal 101 is generally not performed frequently.

  Patent Document 1 describes a method for reducing the influence of the temperature of an RSSI (Received Signal Strength Indicator) signal corresponding to the radio field intensity in order to appropriately correspond to the electric field intensity of the received radio wave.

  Patent Document 2 describes a method in which a communication terminal of a mobile phone system registers a location with a radio base station that is closest among communicable radio base stations.

  Patent Document 3 discloses a method for determining whether or not there is a failure in each radio base station by reducing the transmission power of one radio base station among a plurality of radio base stations and controlling the traffic amount of each radio base station. Is described.

JP 2001-203647 A JP 2002-10316 A JP 2011-259133 A

  However, the methods described in Patent Documents 1 to 3 cannot cope with a change in the electric field strength of the radio wave received from the radio base station, and there is a possibility that communication with the radio base station becomes unstable.

  Therefore, an object of the present invention is to provide a communication terminal, a radio communication system, a mobile communication method, and a mobile communication program that can stably communicate with a radio base station.

  A communication terminal according to the present invention includes an electric field strength measuring unit that measures the electric field strength of a received signal based on a radio wave transmitted from a radio base station, and a control unit that stores electric field strength information indicating a measurement result by the electric field strength measuring unit in a storage unit. And a difference calculating means for calculating a difference between the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured by the electric field strength measuring means. The control means is calculated by the difference calculating means. When the difference is equal to or greater than a predetermined value, a search process for searching for another radio base station is performed.

  A radio communication system according to the present invention includes any one of communication terminals and a radio base station.

  In the mobile communication method according to the present invention, the storage means stores the electric field strength measuring step for measuring the electric field strength of the received signal based on the radio wave transmitted by the radio base station, and the electric field strength information indicating the measurement result in the electric field strength measuring step. The difference calculated in the control step, the difference calculation step for calculating the difference between the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured by the electric field intensity measurement means, and the difference calculated in the difference calculation step are predetermined. A search step of searching for another radio base station when the value is equal to or greater than the value of.

  A mobile communication program according to the present invention stores, in a computer, electric field strength measurement processing for measuring electric field strength of a received signal based on radio waves transmitted from a radio base station, and electric field strength information indicating a measurement result in the electric field strength measurement step. Calculated by the difference calculation process, the difference calculation process for calculating the difference between the electric field intensity indicated by the electric field intensity information stored in the storage means, the electric field intensity measured by the electric field intensity measurement means, and the difference calculation process. When the difference is greater than or equal to a predetermined value, a search process for searching for another radio base station is executed.

  ADVANTAGE OF THE INVENTION According to this invention, it can communicate stably with a radio base station.

It is a block diagram which shows the structural example of the communication terminal of the 1st Embodiment of this invention. It is explanatory drawing which shows the measurement of the electric field strength of the received signal by a received electric field strength detection part. It is explanatory drawing which shows a standby state when synchronization is established between a communication terminal and a radio base station. It is a flowchart which shows the operation | movement in the standby state of a communication terminal. It is a flowchart which shows the operation | movement in the standby state of a communication terminal. It is a block diagram which shows the structural example of the communication terminal of the 2nd Embodiment of this invention. It is a block diagram which shows the structural example of the communication terminal of the 3rd Embodiment of this invention. It is a block diagram which shows the structural example of the communication terminal of the 4th Embodiment of this invention. It is a block diagram which shows the structural example of the communication terminal of the 5th Embodiment of this invention. It is explanatory drawing which shows the relationship between the use place which is a place where the communication terminal of PHS is used, and a radio base station. It is explanatory drawing which shows the relationship between the use place which is a place where the communication terminal of PHS is used, and a radio base station.

Embodiment 1. FIG.
A communication terminal according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of a communication terminal 100 according to the first embodiment of this invention. As illustrated in FIG. 1, the communication terminal 100 according to the present embodiment includes a radio unit 110, a memory unit 120, a control unit 130, a radio transmission / reception switching unit 140, and a received signal attenuation unit 150.

  As illustrated in FIG. 1, the control unit 130 includes a main processing unit 131, a received electric field strength detection unit 132, a received signal attenuation control unit 133, and a memory interface control unit 134.

  The control unit 130 is connected to the radio unit 110 and the memory unit 120. Radio section 110 is connected to radio transmission / reception switching section 140 and received signal attenuating section 150. The radio transmission / reception switching unit 140 is connected to the radio unit 110 and the received signal attenuation unit 150. An antenna 160 is connected to the wireless transmission / reception switching unit 140. The reception signal attenuation unit 150 is realized by, for example, an attenuator, and is connected to the reception signal attenuation control unit 133, the radio unit 110, and the radio transmission / reception switching unit 140 of the control unit 130.

  The radio unit 110 performs radio communication with the radio base station 200 (not shown in FIG. 1; see FIG. 3 described later). The memory unit 120 stores information. The radio transmission / reception switching unit 140 inputs the transmission signal input by the radio unit 110 to the antenna 160 and inputs the reception signal based on the radio wave received by the antenna 160 to the reception signal attenuating unit 150. The received signal attenuating unit 150 attenuates the received signal input by the wireless transmission / reception switching unit 140 and inputs the received signal to the wireless unit 110 under the control of the received signal attenuation control unit 133.

  Radio section 110 performs frequency conversion processing and demodulation processing on the received signal input via received signal attenuating section 150. Radio section 110 then inputs the received data obtained by frequency conversion processing and demodulation processing to main processing section 131 of control section 130. In addition, the wireless unit 110 performs modulation processing and frequency conversion processing on transmission data input by the main processing unit 131 of the control unit 130. A transmission signal obtained by performing the modulation process and the frequency conversion process is input to the antenna 160 via the wireless transmission / reception switching unit 140.

  The radio unit 130 inputs the input reception signal to the reception electric field strength detection unit 132 of the control unit 130.

  The received electric field strength detector 132 measures the electric field strength of the input received signal, and stores the electric field strength information indicating the measurement result in the memory unit 120 via the memory interface controller 134. Further, the reception electric field strength detection unit 132 causes the reception signal attenuation unit 150 to attenuate the reception signal when the value of the electric field strength measurement result exceeds a predetermined threshold value (60 dBμV in this example). FIG. 2 is an explanatory diagram showing measurement of the electric field strength of the received signal by the received electric field strength detector 132. As shown in FIG. 2, the received electric field strength detector 132 measures the peak value of the voltage of the received signal input by the wireless unit 130.

The main processing unit 131 generates base station information that identifies the radio base station 200 of the communication counterpart based on the reception data input by the radio unit 110. Then, the main processing unit 131 stores the generated base station information in the base station information management unit 121, which is a predetermined area in the memory unit 120, via the memory interface control unit 134.
In addition, the main processing unit 131 may generate audio information based on the reception data input by the wireless unit 110 and output audio to a speaker (not shown). The main processing unit 131 generates control information for controlling a device (not shown) to which the communication terminal 100 is connected based on the reception data input by the wireless unit 110 and stores the memory via the memory interface control unit 134. The information may be stored in the unit 120 or input to the device.

  Further, the main processing unit 131 may generate transmission data corresponding to audio information input from a microphone (not shown) and input the transmission data to the wireless unit 110. The main processing unit 131 may generate transmission data corresponding to information input from a device connected to the communication terminal 100 and input the transmission data to the wireless unit 110.

  The memory interface control unit 134 of the control unit 130 stores information in the memory unit 120 in accordance with an instruction from the main processing unit 131 and an instruction from the received electric field strength detection unit 132. Note that the memory interface control unit 134 stores the base station information in the base station information management unit 121 of the memory unit 120 in accordance with an instruction from the main processing unit 131.

  Next, the operation of the communication terminal 100 of this embodiment will be described. The communication terminal 100 is in a standby state in which an operation for receiving a communication frame is performed at a cycle of 1.2 seconds based on the PHS standard when the power is on.

  Specifically, the radio wave transmitted from the radio base station 200 is received by the antenna 160, converted into an electric signal, and input to the radio unit 110 via the radio transmission / reception switching unit 140 and the received radio wave attenuation unit 150. Radio section 110 performs reception frequency conversion processing and demodulation processing on the received signal, which is an input electrical signal, to generate received data. Then, the wireless unit 110 inputs the generated reception data to the main processing unit 131 of the control unit 130.

  The main processing unit 131 searches for a portion of a predetermined bit arrangement included in the communication frame in the received data, which is called a unique word. Then, when detecting the unique word, the main processing unit 131 assumes that synchronization has been established with the radio base station 200 and enters a standby state.

  FIG. 3 is an explanatory diagram showing a standby state when synchronization is established between the communication terminal 100 and the radio base station 200. The radio base station 200 transmits a radio wave including a unique word in a communication frame at a cycle of 1.2 seconds. In order to synchronize with the radio base station 200, the communication terminal 100 receives the transmitted radio wave and searches for a unique word. Then, the communication terminal 100 establishes synchronization with the radio base station 200 based on the detected unique word, and continues a standby state in which a communication frame is received at a cycle of 1.2 seconds.

  4 and 5 are flowcharts showing the operation of the communication terminal 100 in the standby state.

  The radio unit 110 receives a reception signal based on the radio wave transmitted from the radio base station 200 at a cycle of 1.2 seconds and inputs the received signal to the reception electric field strength detection unit 132. The reception electric field strength detection unit 132 measures the electric field strength of the reception signal input by the wireless unit 110 (step S101).

  The main processing unit 131 adds 1 to the value of the measurement number counter for counting the number of measurements (step S102). In this example, it is assumed that 0 is set in advance as the value of the measurement number counter, and the value of the measurement number counter becomes 1 in the process of step S102. And the main process part 131 transfers to the process according to the measurement result in the process of step S101 (step S103). That is, the main processing unit 131 proceeds to the process of step S104 when the measurement result of the electric field strength is less than 25 dBμV. Further, when the measurement result of the electric field strength is a value larger than 60 dBμV, the main processing unit 131 proceeds to the process of step S106. When the measurement result of the electric field strength is 25 to 60 dBμV, the main processing unit 131 proceeds to the process of step S109.

  In step S104, the main processing unit 131 resets the measurement number counter and sets the value of the measurement number counter to 0 (step S104). Then, the main processing unit 131 starts searching for another radio base station (step S105) and ends the process.

  The reason why the process of steps S104 and S105 is performed to search for another radio base station when the electric field strength measurement result is less than 25 dBμV will be described. When the measurement result of the electric field strength is less than 25 dBμV, the electric field strength of the received signal based on the radio wave transmitted from the radio base station 200 is smaller than the lower limit of the appropriate range of the received electric field strength according to the PHS standard. This is because communication between the communication terminal 100 and the radio base station 200 becomes unstable.

The main processing unit 131 determines whether or not the value of the measurement number counter is 3 or more in the process of step S106 (step S106). When the value of the measurement number counter is not 3 or more, that is, when the value is 1 or 2 (N in Step S106), the main processing unit 131 ends the process. Then, after 1.2 seconds, the process is repeated again from step S101. When the value of the measurement number counter is 3 or more (Y in step S106), the main processing unit 131 causes the reception signal attenuation control unit 133 to respond to the measurement result of the reception electric field strength detection unit 132 in the process of step S101. Instructs the attenuation of the received signal. When the value of the measurement number counter is 3 or more, the measurement result of the electric field strength exceeds 60 dBμV three times in succession. Then, it is determined that the electric field intensity of the radio wave transmitted from radio base station 200 is stable and too strong. Therefore, the main processing unit 131 attenuates the received signal corresponding to the radio wave according to the measurement result.
Then, the attenuated received signal is input to the radio unit 110.

  The reception signal attenuation control unit 133 causes the reception signal attenuation unit 150 to attenuate the reception signal at a rate corresponding to the measurement result of the electric field strength by the reception electric field strength detection unit 132, for example, according to the instruction from the main processing unit 131. Instruct. For example, the reception signal attenuation unit 150 attenuates the reception signal output from the wireless transmission / reception switching unit 140 according to the instruction and inputs the signal to the wireless unit 110 (step S107). Then, the main processing unit 131 resets the measurement number counter, sets the value of the measurement number counter to 0 (step S108), and ends the process. Then, after 1.2 seconds, the process is repeated again from step S101.

  In step S109, the main processing unit 131 resets the measurement number counter and sets the value of the measurement number counter to 0 (step S109). The main processing unit 131 stores the electric field strength information indicating the electric field strength of the received radio wave in the base station information management unit 121 in association with the base station information generated based on the reception data input by the radio unit 110. It is confirmed whether it has been done (step S110).

  When the main processing unit 131 determines that the field strength information is not stored in the base station information management unit 121 in step S110 (N in step S110), the main processing unit 131 performs the following processing. That is, the main processing unit 131 stores the electric field strength information indicating the measurement result in the process of step S101 in the base station information management unit 121 via the memory interface control unit 134 in association with the base station information (step S111). Then, the main processing unit 131 ends the process. Then, after 1.2 seconds, the process is repeated again from step S101.

  When the main processing unit 131 determines that the field strength information is stored in the base station information management unit 121 in step S110 (Y in step S110), the main processing unit 131 performs the following processing. That is, the main processing unit 131 compares the measurement result (also referred to as a measurement value) in the process of step S101 with the electric field strength (also referred to as a stored value) indicated by the electric field strength information stored in the base station information management unit 121. (Step S112).

  In step S112, the main processing unit 131 determines whether the difference between the measurement result in step S101 and the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is 30 dBμV or more. Is determined (step S112). When the difference between the measurement result in the process of step S101 and the electric field intensity indicated by the electric field intensity information stored in the base station information management unit 121 is 30 dBμV or more (Y in step S112), The process proceeds to step S104. That is, the main processing unit 131 resets the measurement number counter and sets 0 to the value of the measurement number counter (step S104). Then, the main processing unit 131 starts searching for another radio base station (step S105) and ends the process. If the difference between the measurement result in the process of step S101 and the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is 30 dBμV or more, the electric field strength based on the radio wave transmitted by the base station 200 Is unstable. Therefore, it is considered that communication between the communication terminal 100 and the base station 200 is unstable. Therefore, the main processing unit 131 starts searching for another radio base station and attempts to communicate with another radio base station.

  When the difference between the measurement result in step S101 and the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is less than 30 dBμV (N in step S112), The process proceeds to step S113. The main processing unit 131 determines whether or not the electric field strength of the measurement result of the process of step S101 is 40 dBμV or more in the process of step S113 (step S113). When the electric field strength of the measurement result of step S101 is not 40 dBμV or higher (N in step S113), that is, when the electric field strength of the measurement result of step S101 is less than 40 dBμV, the main processing unit 131 performs step S116. Move on to processing. When the electric field strength of the measurement result of the process in step S101 is 40 dBμV or more (Y in step S113), the main processing unit 131 proceeds to the process in step S114.

  The main processing unit 131 determines whether or not the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is 40 dBμV or more in the processing of step S114 (step S114). When the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is not 40 dBμV or more (N in Step S114), that is, when the electric field strength is less than 40 dBμV, the main processing unit 131 The process ends. Then, the measurement result in the process of step S101 is not stored in the base station information management unit 121, that is, the stored content in the base station information management unit 121 is not updated, and the process is repeated again from step S101 after 1.2 seconds. .

  When the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is 40 dBμV or more (Y in step S114), the main processing unit 131 performs the following processing. That is, the main processing unit 131 compares the measurement result in the process of step S101 with the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 (step S115).

  When the value of the measurement result in step S101 is equal to or greater than the value of the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 (Y in step S115), the main processing unit 131 performs step The process proceeds to S111. Then, the electric field strength information indicating the measurement result in the process of step S101 is associated with the base station information and stored in the base station information management unit 121 via the memory interface control unit 134 (step S111). That is, the electric field strength information stored in the base station information management unit 121 is updated to indicate the value of the measurement result in the process of step S101.

  In addition, the main processing unit 131 determines that the value of the measurement result in the process of step S101 is less than the value of the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 (N in step S115). The process is terminated. Then, the measurement result in the process of step S101 is not stored in the base station information management unit 121, that is, the stored content in the base station information management unit 121 is not updated, and the process is repeated again from step S101 after 1.2 seconds. .

  The reason for ending the process without storing the measurement result when N in step S114 or N in step S115 will be described below.

  In general, the communication terminal 100 is stable with a base station that transmits a radio wave that has a received signal strength of 40 dBμV, which is the middle of the range of an appropriate received field strength according to the PHS standard, with the received signal strength being stable. It is thought that communication can be performed.

  In the present embodiment, when the difference between the measured value and the stored value is 30 dBμV or more in the process of step S112, the process proceeds to a process of searching for another base station. In addition, the measurement value exceeding 60 dBμV is not stored in the process of step S103. Further, the processing of steps S114 and 115 is performed when the measured value is 40 dBμV or more.

  Then, when it is determined as N in the process of step S114, that is, when the stored value is less than 40 dBμV, when the stored value is updated to the measured value, the stored value becomes 40 dBμV or more. Then, even if the measured value of the processing result of step S101 after the next time is 40 dBμV or more, it is not determined that the difference between the measured value and the stored value is 30 dBμV or more in the processing of step S112. Therefore, if the stored value is updated across 40 dBμV according to the variation of the measurement value, it is considered that the allowable range for the variation of the measurement value is substantially expanded.

  Therefore, when it is determined as N in the process of step S114, that is, when the stored value is less than 40 dBμV, the process is terminated without updating the stored value to the measured value.

  Further, when it is determined as N in the process of step S115, that is, when the measured value is less than the stored value, when the stored value is updated to the measured value, the stored value becomes closer to 40 dBμV. Then, even if the measured value of the processing result of step S101 after the next time fluctuates below 40 dBμV, it is difficult to determine that the difference between the measured value and the stored value is 30 dBμV or more in the processing of step S112. Therefore, if the stored value is updated to a value close to 40 dBμV according to the variation of the measurement value, it is considered that the allowable range for the variation of the measurement value is substantially expanded.

  Therefore, when N is determined in the process of step S115, that is, when the measured value is closer to 40 dBμV than the stored value, the process is terminated without updating the stored value to the measured value. .

  The main processing unit 131 determines whether or not the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is 40 dBμV or more in the processing of step S116 (step S116). When the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is 40 dBμV or more (Y in step S116), the main processing unit 131 ends the processing. Then, the measurement result in the process of step S101 is not stored in the base station information management unit 121, that is, the stored content in the base station information management unit 121 is not updated, and the process is repeated again from step S101 after 1.2 seconds. .

  When the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 is not 40 dBμV or more (N in step S116), the main processing unit 131 has an electric field strength indicated by the electric field strength information of 40 dBμV. If it is less, the following processing is performed. That is, the main processing unit 131 compares the measurement result in the process of step S101 with the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 (step S117).

  When the value of the measurement result in the process of step S101 is less than the value of the electric field strength indicated by the electric field intensity information stored in the base station information management unit 121 (N in step S117), the main processing unit 131 performs step The process proceeds to S111. Then, the electric field strength information indicating the measurement result in the process of step S101 is associated with the base station information and stored in the base station information management unit 121 via the memory interface control unit 134 (step S111).

  In addition, the main processing unit 131 determines that the value of the measurement result in the process of step S101 is equal to or greater than the value of the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 (Y in step S117). The process is terminated. Then, the measurement result in the process of step S101 is not stored in the base station information management unit 121, that is, the stored content in the base station information management unit 121 is not updated, and the process is repeated again from step S101 after 1.2 seconds. .

  The reason why the process is terminated without storing the measurement result in the case of Y in step S116 or in the case of Y in step S117 will be described below.

  As described above, in general, the communication terminal 100 transmits a radio wave whose electric field intensity of a received signal is stable and becomes 40 dBμV which is the middle of an appropriate range of the received electric field intensity according to the PHS standard. It is considered that the station can communicate with the station stably.

  In the present embodiment, as described above, when the difference between the measured value and the stored value is 30 dBμV or more in the process of step S112, the process proceeds to a process of searching for another base station. Furthermore, the measurement value that is less than 25 dBμV is not stored in the process of step S103. Moreover, the process of step S116,117 is performed when a measured value is less than 40 dBmicrovolt.

  Then, when it is determined as Y in the process of step S116, that is, when the stored value is 40 dBμV or more, when the stored value is updated to the measured value, the stored value becomes a value less than 40 dBμV. Then, even if the measured value of the processing result in step S101 after the next time is less than 40 dBμV, it is not determined in the processing in step S112 that the difference between the measured value and the stored value is 30 dBμV or more. Therefore, as described above, if the stored value is updated across 40 dBμV in accordance with the variation of the measured value, it is considered that the allowable range for the variation of the measured value is substantially expanded.

  Therefore, when it is determined as Y in the process of step S115, that is, when the stored value is 40 dBμV or more, the process is terminated without updating the stored value to the measured value.

  In addition, when it is determined as Y in the process of step S117, that is, when the measured value is equal to or greater than the stored value, the stored value becomes closer to 40 dBμV if the stored value is updated to the measured value. Then, even if the measured value of the processing result of step S101 after the next time fluctuates by 40 dBμV or more, it is difficult to determine that the difference between the measured value and the stored value is 30 dBμV or more by the processing of step S112. Therefore, as described above, if the stored value is updated to a value close to 40 dBμV according to the variation of the measurement value, it is considered that the allowable range for the variation of the measurement value is substantially expanded.

  Therefore, when it is determined as Y in the process of step S117, that is, when the measured value is closer to 40 dBμV than the stored value, the process is terminated without updating the stored value to the measured value. .

  According to the present embodiment, when the electric field strength of the received signal based on the radio wave transmitted by the radio base station 200 during the standby operation becomes less than 25 dBμV, the search for another radio base station is started. Therefore, it is possible to avoid the use of a radio base station that transmits a radio wave whose electric field strength becomes unstable. Therefore, communication quality can be improved and stable communication with the radio base station can be performed.

  Further, according to the present embodiment, when the electric field strength of the received signal based on the radio wave transmitted by the radio base station 200 during the standby operation exceeds 60 dBμV continuously for three measurement occasions, the received signal attenuation unit 150 Attenuates the received signal and inputs it to the radio unit 110. Therefore, it is possible to automatically control the intensity of the received signal input to the radio unit 110 within a predetermined range. Therefore, communication quality can be improved and stable communication with the radio base station can be performed.

When a communication terminal is fixedly installed in a telemetering system or the like, it takes a considerable operation period to check the communication environment with surrounding radio base stations.
Depending on the confirmation result, it may be necessary to go to the installation location again and adjust the communication terminal. According to the present embodiment, during a standby operation, a radio base station that is a radio wave transmission source that can be stably received at an appropriate intensity is searched based on radio waves received at a cycle of 1.2 seconds. Therefore, the communication environment at the place where the communication terminal is installed can be confirmed in a short time. In addition, according to the present embodiment, control is performed so as to communicate with a radio base station that can stably receive radio waves with appropriate strength. There is no need to make adjustments. Therefore, it is possible to save labor costs and time required for confirmation of the communication environment and readjustment of the communication terminal. Further, the communication terminal can be made to communicate with a radio base station that is a transmission source of radio waves that can be stably received at an appropriate intensity without frequently requiring maintenance work of the communication terminal. Thus, labor costs and time required for maintenance work and the like can be saved.

  A PHS communication terminal consumes more power than a standby state when searching for a radio base station. According to the present embodiment, control is performed so as to perform communication with a radio base station that is a radio wave transmission source that can be stably received with an appropriate intensity, so that the number of searches of the radio base station can be reduced. Therefore, the power consumption of the communication terminal can be reduced. Therefore, when the communication terminal is driven by a battery, the charge cycle of the battery can be extended. Then, deterioration due to charging of the battery can be satisfactorily suppressed.

Embodiment 2. FIG.
Next, a communication terminal according to a second embodiment of the present invention will be described with reference to the drawings. The communication terminal 100 according to the first embodiment attenuates the received signal and inputs it to the radio unit 110 when the electric field strength of the received signal is too strong. The communication terminal 102 of the present embodiment further attenuates the transmission signal and inputs it to the antenna 160 when the electric field strength of the reception signal is strong.

  FIG. 6 is a block diagram illustrating a configuration example of the communication terminal 102 according to the second embodiment of this invention. As illustrated in FIG. 6, the communication terminal 102 according to the present embodiment includes a transmission signal attenuation control unit 171 and a transmission signal attenuation unit 180 in addition to the configuration of the communication terminal 100 according to the first embodiment illustrated in FIG. 1. In the communication terminal 102 of the present embodiment, the same components as those of the communication terminal 100 of the first embodiment shown in FIG.

  The transmission signal attenuation unit 180 is realized by, for example, an attenuator, and attenuates the transmission signal output by the radio unit 110. The transmission signal attenuation control unit 171 is included in the control unit 170 and controls the transmission signal attenuation unit 180 based on the measurement result of the reception signal by the reception electric field strength detection unit 132.

  The transmission signal attenuation control unit 171 transmits the transmission signal attenuation unit 180 when the measurement result of the reception signal measured by the reception field strength detection unit 132 indicates that the radio wave transmitted by the radio base station 200 is stable and strong. Attenuate the transmitted signal.

  This is because when the radio wave transmitted by the radio base station 200 is stably strong, the radio base station 200 is near the communication terminal 102 and it is considered unnecessary to increase the transmission power of the communication terminal 102. . Note that the case where the radio wave transmitted by the radio base station 200 is stably strong is, for example, the case where the measurement result of the received signal measured by the received electric field strength detector 132 exceeds 60 dBμV three times in succession. Further, the transmission signal attenuation control unit 171 may control the attenuation of the transmission signal by the transmission signal attenuation unit 180 according to the measurement result of the reception signal measured by the reception electric field strength detection unit 132.

According to the present embodiment, in addition to the effect similar to the effect by the communication terminal 100 of the first embodiment, the electric field intensity of the radio wave received by the radio base station 200 from the communication terminal 102 is appropriate according to the PHS standard. It can be satisfactorily prevented from becoming stronger than the upper limit of the range of the received electric field intensity.
Then, communication with the radio base station 200 can be performed more stably.

  Note that the transmission signal attenuation control unit 171 may control the radio unit 110 so as to reduce the transmission output power. According to such a configuration, the power consumption of the communication terminal 102 can be further reduced.

Embodiment 3. FIG.
Next, a communication terminal according to a third embodiment of the present invention will be described with reference to the drawings. The communication terminal 100 according to the first embodiment causes the base station information management unit 121 of the memory unit 120 to store base station information indicating a base station in which the received electric field strength of the transmitted radio wave is within a predetermined range. The communication terminal 103 of the present embodiment further includes a base station that indicates a radio base station that has been determined that the received electric field strength is unstable due to the transmitted radio wave, or a radio base station that has been determined that the received electric field strength is too strong. Information and field strength information are stored.

  FIG. 7 is a block diagram illustrating a configuration example of the communication terminal 103 according to the third embodiment of this invention. As illustrated in FIG. 7, the communication terminal 103 according to the present embodiment includes a base station history management unit 191 in the memory unit 190 in addition to the configuration of the communication terminal 100 according to the first embodiment illustrated in FIG. 1. In the communication terminal 103 of the present embodiment, the same components as those of the communication terminal 100 of the first embodiment shown in FIG.

  The base station history management unit 191 is realized by a predetermined area in the memory unit 190.

The main processing unit 131 obtains base station information indicating the radio base station determined that the electric field strength due to the transmitted radio wave is unstable, and the radio base station determined as the electric field strength due to the transmitted radio wave is too strong, and the electric field strength. The base station history management unit 191 stores the electric field strength information shown. For example, the main processing unit 131 determines that the electric field strength due to the transmitted radio wave is unstable based on the measurement result of the received signal by the received electric field strength detection unit 132, or determines that the electric field strength is too strong. To do. Specifically, the main processing unit 131, for example, has a difference between the electric field strength measured by the received electric field strength detection unit 132 and the electric field strength indicated by the electric field strength information stored in the base station information management unit 121 of 30 dBμV or more. If it is, it will be judged that the electric field strength by the transmitted radio wave is unstable.
In addition, for example, when the received electric field strength of three consecutive measurement results by the received electric field strength detector 132 exceeds 60 dBμV, the main processing unit 131 determines that the electric field strength due to the transmitted radio wave is too strong.

  According to this embodiment, in addition to the effect similar to the effect by the communication terminal 100 of the first embodiment, the base station information and the received electric field strength information stored in the base station history management unit 191 are used for failure analysis. The effect that it is possible can be produced. In addition, when power is supplied from the battery to the communication terminal 103, the base station information and the electric field stored in the base station history management unit 191 are generated when the problem that the storage amount of the battery rapidly decreases occurs. The strength information can be used for analysis of the problem. Then, it becomes possible to analyze a failure and a problem quickly and appropriately. And it becomes possible to solve the said fault and problem rapidly.

  Further, by providing the base station information and the received electric field strength information stored in the base station history management unit 191 to the administrator of the radio base station 200, it becomes possible to quickly and appropriately analyze a failure or a problem. And it becomes possible to solve the said fault and problem rapidly.

Embodiment 4 FIG.
Next, a communication terminal according to a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a block diagram illustrating a configuration example of the communication terminal 104 according to the fourth embodiment of this invention. As shown in FIG. 8, the communication terminal 104 of the present embodiment includes a received data frame error detection unit 173 in addition to the configuration of the communication terminal 100 of the first embodiment shown in FIG. In addition, the communication terminal 104 according to the present embodiment includes a reception signal attenuation unit 151 that can attenuate a reception signal with three levels of attenuation. In the communication terminal 104 of the present embodiment, the same components as those of the communication terminal 100 of the first embodiment shown in FIG.

  The reception data frame error detection unit 173 is included in the control unit 172. The reception data frame error detection unit 173 detects a CRC (Cyclic Redundancy Check) error or the like generated in the data input to the main processing unit 131 by the radio unit 110. Then, when the reception data frame error detection unit 173 detects an error, the main processing unit 131 confirms that the error has occurred and the electric field strength information indicating the electric field strength of the reception signal corresponding to the data in which the error has occurred. The error information shown is stored in the memory unit 120 in association with each other.

  The main processing unit 131 controls the reception signal attenuating unit 151 so that the reception signal is not input to the radio unit 110 with the electric field strength indicated by the electric field strength information associated with the error information stored in the memory unit 120. Attenuate the received signal.

  A radio control IC (Integrated Circuit) that realizes the radio unit 110 generally has a deviation in characteristics between each channel and frequency band used in communication, and further, there is a deviation depending on the electric field strength of the received signal. . Therefore, communication quality may deteriorate at a specific electric field strength regardless of the magnitude of the electric field strength. Then, a decrease in communication quality can be determined based on the number of errors such as CRC errors. According to the present embodiment, the received signal attenuating unit 151 attenuates the received signal according to the error information stored in the memory unit 120, and the received signal is input to the radio unit 110 with a specific electric field strength that degrades communication quality. Can be prevented. Therefore, according to this embodiment, in addition to the effect similar to the effect by the communication terminal 100 of 1st Embodiment, the fall of the communication quality in specific electric field strength can be prevented favorably.

Embodiment 5. FIG.
A fifth embodiment of the present invention will be described with reference to the drawings. FIG. 9 is a block diagram illustrating a configuration example of the communication terminal 10 according to the fifth embodiment of this invention. As shown in FIG. 9, the communication terminal 10 according to the fifth embodiment of the present invention includes an electric field strength measuring unit 11 (corresponding to the received electric field strength detector 132), a control unit 12 (corresponding to the main processing unit 131), and Difference calculation means 13 (corresponding to main processing unit 131) is included.

  The electric field strength measuring unit 11 measures the electric field strength of the received signal based on the radio wave transmitted by the radio base station 20. The control means 12 stores the electric field strength information indicating the measurement result by the electric field strength measuring means 11 in the storage means (corresponding to the memory units 120 and 190). The difference calculation means 13 calculates the difference between the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured by the electric field strength measurement means 11.

  Then, when the difference calculated by the difference calculating unit 13 is equal to or greater than a predetermined value, the control unit 12 performs a search process for searching for another radio base station.

  According to this embodiment, the communication terminal 10 can stably communicate with a radio base station.

  In addition, the structure of the communication terminal of each embodiment described above can be combined suitably. Specifically, for example, the communication terminal 104 in the fourth embodiment may further include a memory unit 190 including a base station history management unit 191. Further, for example, the communication terminal 102 in the second embodiment may further include a reception data frame error detection unit 173.

  Moreover, although a part or all of said embodiment can be described also as the following additional remarks, it is not restricted to the following.

  (Appendix 1) Electric field strength measuring means for measuring the electric field strength of the received signal based on the radio wave transmitted by the radio base station, control means for storing electric field strength information indicating the measurement result by the electric field strength measuring means in the storage means, Difference calculating means for calculating a difference between the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured by the electric field intensity measuring means, and the control means includes the difference calculating means A communication terminal that performs a search process for searching for another radio base station when the difference calculated by is greater than or equal to a predetermined value.

  (Supplementary note 2) The control means has both the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured by the electric field intensity measuring means being not less than a predetermined value, and When the electric field strength measured by the electric field strength measuring unit is equal to or higher than the electric field strength indicated by the electric field strength information stored in the storage unit, the electric field strength information stored in the storage unit is measured. The communication terminal according to appendix 1, wherein the communication terminal is updated to indicate the electric field strength measured by the means.

  (Supplementary note 3) The control means has both the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured by the electric field intensity measuring means being less than a predetermined value, and When the electric field strength measured by the electric field strength measuring unit is less than the electric field strength indicated by the electric field strength information stored in the storage unit, the electric field strength information stored in the storage unit is The communication terminal according to supplementary note 1 or supplementary note 2, which is updated so as to indicate the electric field strength measured by the means.

  (Supplementary Note 4) Including a reception attenuation means for attenuating the received signal in accordance with the control of the control means, the control means is an upper limit in which the electric field intensity measured by the electric field intensity measurement means is set in advance continuously for a predetermined number of times or more. The communication terminal according to any one of supplementary notes 1 to 3, wherein the reception attenuation unit attenuates the reception signal when the value exceeds the value.

  (Additional remark 5) The said control means is any one of Additional remark 1 to Additional remark 4 which searches another wireless base station, when the electric field strength which the said electric field strength measurement means measured is less than the preset lower limit. The communication terminal described in 1.

  (Appendix 6) Transmission signal generation means for generating a transmission signal for transmission to the radio base station, and the electric field strength measured by the electric field strength measurement means exceeds a preset upper limit value continuously for a predetermined number of times or more. And a transmission attenuation means for attenuating the transmission signal transmitted by the transmission signal generation means.

  (Additional remark 7) When the said control means memorize | stores the said electric field strength information in the said memory | storage means, the said radio base station of the transmission source of the electromagnetic wave according to the received signal by which the electric field strength shown by the said electric field strength information was measured The communication terminal according to any one of supplementary note 1 to supplementary note 6 in which base station information indicating ??? is stored in the storage unit in association with the electric field strength information.

  (Additional remark 8) It includes a reception attenuation means for attenuating the received signal in accordance with the control of the control means, and the control means receives the error in response to occurrence of an error in received data based on the received signal having a predetermined electric field strength. The communication terminal according to any one of appendix 1 to appendix 7, wherein the attenuation unit attenuates the reception signal having the predetermined electric field strength.

  (Supplementary note 9) A wireless communication system comprising the communication terminal according to any one of supplementary note 1 to supplementary note 8 and the wireless base station.

  (Additional remark 10) The electric field strength measurement step which measures the electric field strength of the received signal based on the radio wave transmitted by the radio base station, and the control step which stores the electric field strength information indicating the measurement result in the electric field strength measurement step in the storage means, The difference calculating step for calculating the difference between the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured by the electric field strength measuring means, and the difference calculated in the difference calculating step is a predetermined value. And a search step of searching for another radio base station when the value is equal to or greater than the value.

  (Additional remark 11) Control which makes a computer memorize | store in a memory | storage means the electric field strength measurement process which measures the electric field strength of the received signal based on the electromagnetic wave which the wireless base station transmitted, and the electric field strength information which shows the measurement result in the said electric field strength measurement step Difference calculated between the processing, the electric field strength indicated by the electric field strength information stored in the storage means, and the electric field strength measured by the electric field strength measuring means, and the difference calculated in the difference calculating process A mobile communication program for executing a search process for searching for another radio base station when is equal to or greater than a predetermined value.

10, 100, 102, 103, 104 Communication terminal 11 Electric field strength measurement means 12 Control means 13 Difference calculation means 20 Radio base station 110 Radio part 120, 190 Memory part 121 Base station information management part 130, 170, 172 Control part 131 Main Processing unit 132 Reception electric field strength detection unit 133 Reception signal attenuation control unit 134 Memory interface control unit 140 Wireless transmission / reception switching unit 150, 151 Reception signal attenuation unit 160 Antenna 171 Transmission signal attenuation control unit 173 Reception data frame error detection unit 180 Transmission signal attenuation Unit 191 base station history management unit 200 radio base station

Claims (12)

Electric field strength measuring means for measuring the electric field strength of the received signal based on the radio wave transmitted by the radio base station;
Control means for storing, in a storage means, electric field strength information indicating a measurement result by the electric field strength measuring means;
Difference calculating means for calculating a difference between the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured by the electric field strength measuring means;
Wherein when difference the difference calculation means has calculated is not less than a predetermined value, have row a search process to search for other radio base stations,
The control means is such that both the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured by the electric field intensity measuring means are not less than a predetermined value, and the electric field intensity When the electric field strength measured by the measuring means is equal to or higher than the electric field strength indicated by the electric field strength information stored in the storage means, the electric field strength measurement means measures the electric field strength information stored in the storage means. A communication terminal that is updated to indicate electric field strength . The control means has both the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured by the electric field intensity measuring means being less than a predetermined value, and the electric field intensity. When the electric field strength measured by the measuring means is less than the electric field strength indicated by the electric field strength information stored in the storage means, the electric field strength measurement means measures the electric field strength information stored in the storage means. The communication terminal according to claim 1, wherein the communication terminal is updated to indicate electric field strength. Electric field strength measuring means for measuring the electric field strength of the received signal based on the radio wave transmitted by the radio base station;
Control means for storing, in a storage means, electric field strength information indicating a measurement result by the electric field strength measuring means;
Difference calculating means for calculating a difference between the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured by the electric field strength measuring means;
The control means performs a search process for searching for another radio base station when the difference calculated by the difference calculation means is a predetermined value or more,
The control means has both the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured by the electric field intensity measuring means being less than a predetermined value, and the electric field intensity. When the electric field strength measured by the measuring means is less than the electric field strength indicated by the electric field strength information stored in the storage means, the electric field strength measurement means measures the electric field strength information stored in the storage means. A communication terminal that is updated to indicate electric field strength . Receiving attenuation means for attenuating the received signal according to the control of the control means;
The control means causes the reception attenuation means to attenuate the reception signal when the electric field intensity measured by the electric field intensity measurement means exceeds a preset upper limit value continuously for a predetermined number of times or more. The communication terminal according to claim 3. The control unit searches for another radio base station when the electric field strength measured by the electric field strength measuring unit is less than a preset lower limit value. Communication terminal. Transmission signal generating means for generating a transmission signal for transmission to the radio base station;
Transmission attenuation means for attenuating the transmission signal transmitted by the transmission signal generation means when the electric field intensity measured by the electric field intensity measurement means exceeds a preset upper limit value continuously for a predetermined number of times or more; The communication terminal according to any one of claims 1 to 5. The control means, when storing the electric field strength information in the storage means, a base station indicating the radio base station that is a transmission source of the radio wave according to the received signal whose electric field strength indicated by the electric field strength information is measured The communication terminal according to claim 1, wherein information is stored in the storage unit in association with the electric field strength information. A communication terminal according to any one of claims 1 to 7;
A wireless communication system comprising the wireless base station. An electric field strength measuring step for measuring an electric field strength of a received signal based on a radio wave transmitted by a radio base station;
A control step of storing electric field strength information indicating a measurement result in the electric field strength measurement step in a storage means;
A difference calculating step of calculating a difference between the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured in the electric field strength measuring step ;
Look including a searching step of differences calculated by the difference calculating step searches for other radio base station is equal to or greater than a predetermined value,
In the control step, the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured in the electric field strength measurement step are both greater than or equal to a predetermined value, and the electric field strength When the electric field strength measured in the measurement step is equal to or higher than the electric field strength indicated by the electric field strength information stored in the storage means, the electric field strength information stored in the storage means is measured in the electric field strength measurement step. A mobile communication method, characterized by updating to indicate electric field strength . An electric field strength measuring step for measuring an electric field strength of a received signal based on a radio wave transmitted by a radio base station;
A control step of storing electric field strength information indicating a measurement result in the electric field strength measurement step in a storage means;
A difference calculating step of calculating a difference between the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured in the electric field strength measuring step;
A search step of searching for another radio base station when the difference calculated in the difference calculation step is a predetermined value or more,
In the control step, both the electric field strength indicated by the electric field strength information stored in the storage means and the electric field strength measured in the electric field strength measurement step are less than a predetermined value, and the electric field strength When the electric field strength measured in the measurement step is less than the electric field strength indicated by the electric field strength information stored in the storage means, the electric field strength information stored in the storage means is measured in the electric field strength measurement step. Update to show field strength
A mobile communication method characterized by the above. On the computer,
Electric field strength measurement processing for measuring the electric field strength of the received signal based on the radio wave transmitted by the radio base station;
A control process for storing electric field strength information indicating a measurement result in the electric field strength measurement step in a storage means;
A difference calculation process for calculating a difference between the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured in the electric field intensity measurement process ;
When the difference calculated in the difference calculation process is equal to or greater than a predetermined value, a search process for searching for another radio base station is executed ,
In the control process, both the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured in the electric field intensity measurement process are not less than a predetermined value, and the electric field intensity When the electric field strength measured by the measurement process is equal to or higher than the electric field intensity indicated by the electric field strength information stored in the storage unit, the electric field strength information stored in the storage unit is measured by the electric field intensity measurement process. A mobile communication program for updating to show electric field strength . On the computer,
Electric field strength measurement processing for measuring the electric field strength of the received signal based on the radio wave transmitted by the radio base station;
A control process for storing electric field strength information indicating a measurement result in the electric field strength measurement step in a storage means;
A difference calculation process for calculating a difference between the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured in the electric field intensity measurement process;
When the difference calculated in the difference calculation process is equal to or greater than a predetermined value, a search process for searching for another radio base station is executed,
In the control process, both the electric field intensity indicated by the electric field intensity information stored in the storage means and the electric field intensity measured in the electric field intensity measurement process are less than a predetermined value, and the electric field intensity When the electric field intensity measured in the measurement process is less than the electric field intensity indicated by the electric field intensity information stored in the storage unit, the electric field intensity information stored in the storage unit is measured in the electric field intensity measurement process. A mobile communication program for updating to indicate electric field strength .

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