JP6331578B2 - Wireless terminal device and wireless communication system - Google Patents

Description

  The present invention relates to a wireless terminal device and a wireless communication system.

  Conventionally, in wireless communication between a mobile station and a base station, TPC (Transmission Power Control) is known as a technique for controlling power required for data transmission from the mobile station to the base station.

  In TPC, first, a base station receives data from a mobile station and detects its reception level. The base station transmits a TPC value corresponding to the detected reception level to the mobile station. Specifically, the base station transmits a TPC value instructing power-up when the detected reception level is a predetermined value or less. On the other hand, if the detected reception level is higher than a predetermined value, the base station transmits a TPC value indicating power down. The TPC value is transmitted for each frame. That is, TPC is executed in units of frames. The reception level at the base station can be controlled within an appropriate range by such TPC.

Japanese Patent Laid-Open No. 2008-17709

  However, in the above-described technique, the mobile station controls the transmission power of the mobile station based on an instruction from the base station. Therefore, a time lag may occur in the transmission power control timing depending on the state of the mobile station. That is, when the mobile station is moving from the cell edge of the base station to the base station side, as described above, the base station instructs the mobile station to decrease the TPC value of the mobile station. . For example, when the mobile station passes through the vicinity of the base station at a high speed and moves away from the base station, the above instruction on the base station side does not catch up, and the transmission power control on the mobile station side does not meet the number of frames. There will be a delay. As a result, the transmission power of the mobile station becomes an insufficient value that does not match the reception level. This destabilizes communication between the mobile station and the base station, and in the worst case, communication between the mobile station and the base station may be disconnected.

  The disclosed technology has been made in view of the above, and an object thereof is to provide a wireless terminal device and a wireless communication system that improve the accuracy of TPC.

  According to an aspect of the disclosure, a history of a change amount of timing for transmitting data to a radio base station is recorded, a cumulative value of the recorded change amount is monitored, and based on a comparison result between the cumulative value and a first threshold value The received control value is adjusted.

  According to the disclosed aspect, the accuracy of TPC can be improved.

FIG. 1 is a diagram illustrating an example of a wireless communication system according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a terminal according to the first embodiment. FIG. 3 is a block diagram illustrating an example of a transmission power control unit according to the first embodiment. FIG. 4 is a block diagram illustrating an example of the TPC conversion unit and the transmission power calculation unit according to the first embodiment. FIG. 5 is a block diagram illustrating an example of the base station according to the first embodiment. FIG. 6 is a diagram illustrating a first half portion of a timing chart for explaining transmission power control processing by a terminal. FIG. 7 is a diagram showing the latter half of the timing chart for explaining the transmission power control processing by the terminal. FIG. 8 is a flowchart illustrating an example of processing operation of the terminal. FIG. 9 is a diagram illustrating a hardware configuration example of the terminal. FIG. 10 is a diagram illustrating a hardware configuration example of the base station.

  Hereinafter, embodiments of a wireless terminal device and a wireless communication system disclosed in the present application will be described in detail with reference to the drawings. Note that the wireless terminal device and the wireless communication system disclosed in the present application are not limited by this embodiment.

[Example 1]
[Outline of wireless communication system]
FIG. 1 is a diagram illustrating an example of a wireless communication system according to the first embodiment. In FIG. 1, the wireless communication system 1 includes a wireless terminal device 10 and a wireless base station device 50. Hereinafter, the wireless terminal device may be simply referred to as “terminal” and the wireless base station device may be simply referred to as “base station”. In FIG. 1, a cell C50 corresponds to a cover area of the base station 50. Further, as shown in FIG. 1, it is assumed that the terminal 10 is moving in the direction of the arrow X at high speed.

  The base station 50 transmits a control value (that is, a TPC value) for controlling the transmission power of the terminal 10. The base station 50 transmits a known signal (for example, a pilot signal). Further, the base station 50 transmits timing advance information (that is, “TA (Timing Advance) information”) for controlling the transmission timing of the terminal 10.

  The terminal 10 receives the TPC value, the known signal, and the TA information transmitted from the base station 50. Further, the terminal 10 acquires “path fluctuation information” based on the received known signal. Here, “TA information” is a transmission timing control command transmitted from the base station 50, and the terminal 10 adjusts the change in the distance to the base station 50 based on this command, Data transmission to the station 50 is performed. Further, the “path fluctuation information” is information indicating the amount of change in the transmission timing due to the result of the downlink path search (DownLink tracking control).

  Then, the terminal 10 records the history of the amount of change in the timing for transmitting data to the base station 50 (that is, TA information and path fluctuation information), and monitors the “cumulative value” of the recorded fluctuation amount. Then, the terminal 10 adjusts the received TPC value based on the comparison result between the accumulated value and the “first threshold value”. For example, the terminal 10 adjusts the received TPC value when the accumulated value becomes less than the first threshold value or more than the first threshold value.

  Here, when the terminal 10 is approaching the base station 50, the received TPC value becomes the TPC value instructing the down. In addition, when the terminal 10 is approaching the base station 50 at a high speed, the fluctuation amount increases at a fast pace, and thus the accumulation amount also increases at a fast pace. Then, when the accumulated value is less than the first threshold value or more than the first threshold value, it can be determined that the terminal 10 has sufficiently approached the base station 50. At this stage, the terminal 10 receives the received TPC. Adjust the value. That is, the terminal 10 converts the received TPC value into a TPC value instructing up.

  When the terminal 10 determines that the terminal 10 has sufficiently approached the base station 50 by the processing operation of the terminal 10 described above, the received TPC value is converted into a TPC value instructing up. However, it is possible to prevent the transmission power value from being insufficient.

[Example of terminal configuration]
FIG. 2 is a block diagram illustrating an example of a terminal according to the first embodiment. In FIG. 1, the terminal 10 includes an RF (Radio Frequency) receiving unit 11, a path search unit 12, a reception processing unit 13, a transmission power control unit 14, a transmission processing unit 15, and an RF transmission unit 16. .

  The RF receiver 11 receives a radio signal transmitted from the base station 50 via an antenna, and performs reception radio processing (down-conversion, analog digital (A / D) conversion, etc.) on the radio signal. The reception signal thus obtained is output to the path search unit 12 and the reception processing unit 13.

  The path search unit 12 detects a path phase value and acquires path variation information based on a known signal included in the reception signal received from the RF reception unit 11. Then, the path search unit 12 outputs the detected path phase value to the reception processing unit 13, and outputs the acquired path fluctuation information to the transmission power control unit 14 and the transmission processing unit 15.

  The reception processing unit 13 demodulates and decodes the reception signal obtained by the RF reception unit 11, outputs the TPC value of the obtained reception data to the transmission power control unit 14, and transmits TA information to the transmission power control unit 14. The received data other than the TPC value and the TA information are output to the subsequent function unit. That is, the reception processing unit 13 receives the TPC value and TA information transmitted from the base station 50.

  The transmission power control unit 14 inputs the TPC value, TA information, and path fluctuation information, and converts the TPC value when the “conversion condition” is satisfied. Then, the transmission power control unit 14 calculates a transmission power value based on the converted TPC value when the conversion condition is satisfied, and the TPC that is not converted when the conversion condition is not satisfied. A transmission power value is calculated based on the value. The calculated transmission power value is output to the RF transmission unit 16. Thereby, the transmission power control unit 14 sets the transmission power value in the RF transmission unit 16.

  FIG. 3 is a block diagram illustrating an example of a transmission power control unit according to the first embodiment. In FIG. 3, the transmission power control unit 14 includes a TPC conversion unit 21 and a transmission power calculation unit 22.

  The TPC conversion unit 21 uses the TPC value, TA information, and path fluctuation information as input signals, and converts the TPC value when the “conversion condition” is satisfied.

Specifically, the following conditions can be set as the conversion conditions.
(Condition 1) Within the “cumulative value calculation target period”.
(Condition 2) The “cumulative value” is less than the first threshold value and greater than or equal to the first threshold value.

  Further, the TPC conversion unit 21 uses the transmission power value output from the transmission power calculation unit 22 as an input signal, and configures a frame whose transmission power value is equal to or less than the “second threshold” as the “cumulative value calculation target period”. Frame.

  Further, the TPC conversion unit 21 converts the TPC value in the “convertible period”. The “convertible period” is a period from a frame that satisfies the above-described conversion condition to a frame after “the number of set frames”.

  The transmission power calculation unit 22 calculates a transmission power value based on the TPC value received from the TPC conversion unit 21 and outputs the transmission power value to the RF transmission unit 16.

  FIG. 4 is a block diagram illustrating an example of the TPC conversion unit and the transmission power calculation unit according to the first embodiment. In FIG. 4, the TPC conversion unit 21 includes a calculation target period determination unit 31, a monitoring unit 32, a conversion condition determination unit 33, a number control unit 34, and a TPC adjustment unit 35. The monitoring unit 32 includes a timing change amount accumulation unit 36 and a cumulative value calculation unit 37.

  The calculation target period determination unit 31 compares the “second threshold value” set in advance with the transmission power value input in units of frames. The calculation target period determination unit 31 then outputs a notification signal indicating that it is a “cumulative value calculation target period” to the cumulative value calculation unit 37 in a period in which the input transmission power value is equal to or less than the second threshold. .

  The monitoring unit 32 records the history of the change amount of data transmission timing to the base station 50 (that is, TA information and path fluctuation information), and monitors the accumulated value of the change amount in the “cumulative value calculation target period”. For example, the timing change amount accumulation unit 36 records the history of TA information and path fluctuation information received from the reception processing unit 13. Then, the cumulative value calculation unit 37 calculates the cumulative value of the change amount in the “cumulative value calculation target period” for each end of the frame, and outputs it to the conversion condition determination unit 33. That is, since the TA information and the path fluctuation information are sequentially input to the timing change amount accumulation unit 36 for each frame, the cumulative value calculation unit 37 performs new TA information and path fluctuation for each frame of the “cumulative value calculation target period”. A cumulative value is calculated each time information is received.

  The conversion condition determination unit 33 determines whether or not the above-described conversion condition is satisfied. When the condition is satisfied, the “up conversion command” and the “start notification of the convertible period” are sent to the TPC adjustment unit 35 and Output to the number control unit 34. Then, the conversion condition determination unit 33 outputs an “up conversion command” to the TPC adjustment unit 35 and the number control unit 34 for each frame until receiving a “frame number expiration notification” from the number control unit 34.

  The number control unit 34 counts the number of received “up-conversion instructions” after receiving the start notification of the convertible period. That is, the number control unit 34 counts the number of frames for which the “up conversion command” is output from the conversion condition determination unit 33. When the count value reaches the set number of frames, the number control unit 34 outputs a “frame number expiration notification” to the conversion condition determination unit 33. Thereby, one conversion possible period ends.

  The TPC adjustment unit 35 adjusts the input TPC value based on the “up-conversion command” received from the conversion condition determination unit 33 during the conversion possible period. That is, the TPC adjustment unit 35 converts the TPC value indicating down among the TPC values input in the convertible period into a TPC value indicating up and outputs the TPC value to the transmission power calculation unit 22. On the other hand, the TPC adjustment unit 35 outputs the TPC value indicating up among the TPC values input during the conversion possible period to the transmission power calculation unit 22 as it is. Note that the TPC adjustment unit 35 outputs the input TPC value to the transmission power calculation unit 22 as it is even during a period other than the convertible period.

  In FIG. 4, the transmission power calculation unit 22 includes a power value conversion unit 41 and calculation units 42 and 43.

  The power value conversion unit 41 converts the TPC value received from the TPC adjustment unit 35 into a value (dB value) representing an up or down range. Then, the power value conversion unit 41 outputs the dB value that is the conversion result of the TPC value to the calculation unit 42.

  The calculation unit 42 uses the dB value from the power value conversion unit 41 and the output of the calculation unit 42 as input signals, and adds or subtracts the TPC value with respect to the output. This calculation process is executed in units of frames, and the calculation result is output to the calculation unit 43.

  The calculation unit 43 uses the initial value of the transmission power and the calculation result by the calculation unit 42 as input signals, and outputs the addition result of the initial value and the calculation result as a transmission power value. The transmission power value is output to the calculation target period determination unit 31.

  Returning to the description of FIG. 2, the transmission processing unit 15 encodes and modulates transmission data and a known signal (for example, a preamble signal) as input signals, and outputs the obtained transmission signal to the RF transmission unit 16.

  The RF transmitter 16 performs reception radio processing (up-conversion, digital analog (D / A) conversion, etc.) on the transmission signal received from the transmission processor 15. The radio signal thus obtained is transmitted to the base station 50 described later via the antenna.

[Base station configuration]
FIG. 5 is a block diagram illustrating an example of the base station according to the first embodiment. In FIG. 5, the base station 50 includes an RF receiver 51, a reception level detector 52, a reception processor 53, a TPC generator 54, a TA information generator 55, a transmission processor 56, and an RF transmitter. 57.

  The RF receiver 51 receives a radio signal transmitted from the terminal 10 through an antenna, and performs reception radio processing (down-conversion, analog-digital (A / D) conversion, etc.) on the radio signal. The reception signal thus obtained is output to the reception level detection unit 52.

  The reception level detection unit 52 detects the reception level based on the reception signal received from the RF reception unit 51. Information relating to the detected reception level (hereinafter also referred to as “reception level information”) is output to the TPC generation unit 54. Further, the reception level detection unit 52 outputs a reception signal received from the RF reception unit 51 to the reception processing unit 53.

  The reception processing unit 53 demodulates and decodes the reception signal obtained by the RF reception unit 51, outputs the obtained known signal (for example, preamble signal) to the TA information generation unit 55, and receives the received data as a functional unit at the subsequent stage. Output to.

  The TPC generation unit 54 determines a TPC value corresponding to the reception level detected by the reception level detection unit 52, and generates a TPC signal including the determined TPC value. The TPC signal is output to the transmission processing unit 56.

  The TA information generation unit 55 generates TA information based on the reception timing of the known signal received from the reception processing unit 53 and the reference timing. The TA information is output to the transmission processing unit 56.

  The transmission processing unit 56 receives the TPC signal, TA information, and transmission data as input, encodes and modulates, and outputs the obtained transmission signal to the RF transmission unit 57.

  The RF transmitter 57 performs reception radio processing (up-conversion, digital analog (D / A) conversion, etc.) on the transmission signal received from the transmission processor 56. The radio signal obtained in this way is transmitted to the terminal 10 via the antenna.

[Operation example of wireless communication system]
A processing operation example of the wireless communication system 1 having the above configuration will be described. An example of processing operation of the terminal 10 will be mainly described. FIG. 6 is a diagram illustrating a first half portion of a timing chart for explaining transmission power control processing by a terminal. FIG. 7 is a diagram showing the latter half of the timing chart for explaining the transmission power control processing by the terminal. FIG. 8 is a flowchart illustrating an example of processing operation of the terminal.

  As a premise for explaining the operation, as shown in FIG. 6, the TPC value before adjustment is “−” indicating down in the frames F1 to F11, F14, and F16, and the frames F12, F13, F15, and F17 to F19. Then, it is assumed that “+” represents up. The up width and the down width are 2 dB, for example, and the frame period is 1 ms, for example. The second threshold (power threshold) is 18 dB, for example. Further, as shown in FIG. 7, it is assumed that “+12” is set as the first threshold (timing threshold) and “3” is set as the number of set frames.

  6 and 7, the time t is defined in the x-axis direction, that is, the left-right direction, and the transmission power value is defined in the y-axis direction, that is, the vertical direction.

  In FIG. 6, the TPC value before adjustment is “−” representing down in the frames F1 to F11, F14, and F16. Further, the path fluctuation information takes a positive value except for the frames F1 and F2. This is because, as described above, it is assumed that the terminal 10 approaches the base station 50 at a high speed and leaves the base station 50 through the vicinity thereof at a high speed. Similarly, the TA information takes positive values (+7, +5) in the frames F8 and F14.

  The calculation target period determination unit 31 repeatedly determines whether or not the transmission power value is equal to or lower than the second threshold value (power threshold value) (No in step S101). In FIG. 6, the transmission power value of the terminal 10 decreases with time from the frame F1, and becomes equal to the second threshold value (power threshold value) in the frame F5 (Yes in step S101). At this time, a notification signal indicating the “cumulative value calculation target period” is output from the calculation target period determination unit 31 to the cumulative value calculation unit 37, and the “cumulative value calculation target period” starts as shown in FIG. To do. That is, the above (Condition 1) is satisfied.

  Then, the cumulative value calculation unit 37 starts calculating the cumulative value of the change amount (step S102), and calculates the cumulative value of the change amount in the “cumulative value calculation target period” every time the frame ends. Then, the conversion condition determination unit 33 repeatedly determines whether or not the accumulated value is equal to or greater than the first threshold (No at Step S103). In FIG. 7, the calculated cumulative value reaches the first threshold value (timing threshold value) in the frame F9 (Yes in step S103). That is, the above (Condition 2) is satisfied. Here, since (Condition 1) and (Condition 2) are satisfied, the conversion condition determination unit 33 sends an “up-conversion instruction” and a “conversion ready period start notification” to the TPC adjustment unit 35 and the number control unit 34. Output to.

  Then, the TPC adjustment unit 35 adjusts the input TPC value based on the up-conversion command received from the conversion condition determination unit 33 during the conversion possible period (step S104). In FIG. 6, since the TPC value indicates down in the frames F9 to F11, the TPC adjustment unit 35 converts the TPC value indicating down into a TPC value indicating up. As a result, in the frames F9 to F11, the transmission power value is increased.

  The convertible period continues while the up-conversion command is output as many times as the number of installation frames “3” (No in step S105). When the up-conversion command is output the same number of times as the number of installation frames “3”, the convertible period ends (Yes at step S105). Then, the flow ends.

  As described above, according to the present embodiment, the monitoring unit 32 in the terminal 10 records the history of the amount of change in the timing for transmitting data to the base station 50 and monitors the accumulated value of the recorded amount of change. Then, the TPC adjustment unit 35 adjusts the TPC value received from the base station 50 based on the comparison result between the accumulated value and the first threshold value. For example, the TPC adjustment unit 35 adjusts the TPC value received from the base station 50 when the cumulative value monitored by the monitoring unit 32 becomes less than the first threshold value or more than the first threshold value.

  With this configuration of the terminal 10, the “cumulative value of the change amount of data transmission timing” that can be used as an index indicating that the terminal 10 has moved and has approached the vicinity of the base station 50 is equal to or greater than the first threshold. When the terminal 10 is sufficiently close to the base station 50, the TPC value can be adjusted. For this reason, even if the terminal 10 further moves away from the base station 50 at a high speed, the TPC value received from the base station 50 can be adjusted to the TPC value indicating up, so that the transmission power value of the terminal becomes the reception level. It is possible to prevent an insufficient value that does not match. As a result, the accuracy of TPC can be improved.

  In addition, the monitoring unit 32 starts to calculate the cumulative value from the first timing when the transmission power value of the terminal 10 becomes greater than or equal to the second threshold value and less than the second threshold value.

  With this configuration of the terminal 10, since the cumulative value is not calculated when the terminal 10 is far from the base station 50, the processing burden on the terminal 10 can be reduced.

  In the above description, when the “cumulative value of the change amount of data transmission timing” is equal to or greater than the first threshold in the “cumulative value calculation target period”, the TPC adjustment unit 35 receives from the base station 50. Although the description has been made assuming that the TPC value is adjusted, the following changes may be added. That is, the TPC adjustment unit 35 may adjust the TPC value received from the base station 50 in the following cases. In this case, in the “cumulative value calculation target period”, the cumulative value is not less than the first threshold value, and the cumulative value is calculated from the start timing of the cumulative value calculation target period (that is, the first timing). This is a case where the length of time (for example, the number of frames) until the second timing when becomes equal to or greater than the first threshold is equal to or less than the third threshold. That is, in this case, the conversion condition determination unit 33 outputs an “up conversion command” and a “conversion ready period start notification” to the TPC adjustment unit 35 and the number control unit 34. Thereby, since the above-described time length that can be used as a determination index indicating the high-speed movement of the terminal 10 is used, the TPC value can be adjusted only in a situation where the possibility that the terminal 10 is moving at a high speed is higher.

[Other embodiments]
Each component of each part illustrated in the embodiments does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each part is not limited to the one shown in the figure, and all or a part thereof may be functionally or physically distributed / integrated in arbitrary units according to various loads and usage conditions. Can be configured.

  Furthermore, various processing functions performed in each device are performed on a CPU (Central Processing Unit) (or a microcomputer such as an MPU (Micro Processing Unit), MCU (Micro Controller Unit), etc.) in whole or in part. You may make it perform. Various processing functions may be executed entirely or arbitrarily on a program that is analyzed and executed by a CPU (or a microcomputer such as an MPU or MCU) or hardware based on wired logic. .

  The terminal and base station of Example 1 can be realized by the following hardware configuration, for example.

  FIG. 9 is a diagram illustrating a hardware configuration example of the terminal. As illustrated in FIG. 9, the terminal 100 includes an RF (Radio Frequency) circuit 101, a processor 102, and a memory 103.

  Examples of the processor 102 include a central processing unit (CPU), a digital signal processor (DSP), and a field programmable gate array (FPGA). Further, examples of the memory 103 include a random access memory (RAM) such as a SDRAM (Synchronous Dynamic Random Access Memory), a read only memory (ROM), and a flash memory.

  Various processing functions performed by the terminal according to the first embodiment may be realized by executing a program stored in various memories such as a nonvolatile storage medium by a processor included in the amplification device. That is, a program corresponding to each process executed by the path search unit 12, the reception processing unit 13, the transmission power control unit 14, and the transmission processing unit 15 is recorded in the memory 103, and each program is executed by the processor 102. May be. Each process executed by the path search unit 12, the reception processing unit 13, the transmission power control unit 14, and the transmission processing unit 15 is shared and executed by a plurality of processors such as a baseband CPU and an application CPU. May be. The RF receiver 11 and the RF transmitter 16 are realized by the RF circuit 101.

  FIG. 10 is a diagram illustrating a hardware configuration example of the base station. As illustrated in FIG. 10, the base station 200 includes an RF circuit 201, a processor 202, a memory 203, and a network IF (Inter Face) 204. Examples of the processor 202 include a CPU, a DSP, and an FPGA. Examples of the memory 203 include RAM such as SDRAM, ROM, flash memory, and the like.

  Various processing functions performed in the base station according to the first embodiment may be realized by executing a program stored in various memories such as a nonvolatile storage medium by a processor included in the amplification device. That is, a program corresponding to each process executed by the reception level detection unit 52, the reception processing unit 53, the TPC generation unit 54, the TA information generation unit 55, and the transmission processing unit 56 is recorded in the memory 203, Each program may be executed by the processor 202. Further, the RF receiving unit 51 and the RF transmitting unit 57 are realized by the RF circuit 201.

  Here, the base station 200 has been described as an integrated device, but the present invention is not limited to this. For example, the base station 200 may be configured by two separate devices, a wireless device and a control device. In this case, for example, the RF circuit 201 is disposed in the wireless device, and the processor 202, the memory 203, and the network IF 204 are disposed in the control device.

DESCRIPTION OF SYMBOLS 1 Wireless communication system 10 Terminal 11, 51 RF reception part 12 Path search part 13, 53 Reception processing part 14 Transmission power control part 15, 56 Transmission processing part 16, 57 RF transmission part 21 TPC conversion part 22 Transmission power calculation part 31 Calculation Target period determination unit 32 Monitoring unit 33 Conversion condition determination unit 34 Number control unit 35 TPC adjustment unit 36 Timing variation accumulation unit 37 Cumulative value calculation unit 41 Power value conversion unit 42, 43 Calculation unit 50 Base station 52 Reception level detection unit 54 TPC generator 55 TA information generator

Claims (4)

A receiving unit that receives a control value of transmission power transmitted from the radio base station and instructing to increase or decrease transmission power of the radio terminal device ;
A history of the amount of change in timing for transmitting data to the radio base station is recorded, and a monitoring unit that monitors the accumulated value of the recorded amount of change,
Adjustment for converting a control value instructing a decrease in the transmission power out of the received control values into a control value instructing an increase in the transmission power based on a comparison result between the accumulated value and the first threshold value And
A wireless terminal device comprising: The adjusting unit, when the accumulated value reaches the first threshold value or more from less than the first threshold value, the control value indicating the lowering of the transmission power, the control value indicating an increase in the transmission power Convert ,
The wireless terminal device according to claim 1. The monitoring unit starts calculating the cumulative value from a first timing at which the transmission power value of the wireless terminal device is less than or equal to a second threshold value and less than the second threshold value.
The wireless terminal device according to claim 1, wherein the wireless terminal device is a wireless terminal device. A wireless communication system having a wireless base station and a wireless terminal device,
The radio base station is
A transmission unit for transmitting a control value for instructing an increase or decrease in transmission power of the wireless terminal device;
A receiving unit that receives a signal transmitted from the wireless terminal device using a transmission power value based on the transmitted control value;
Comprising
The wireless terminal device
A receiving unit that receives a control value of transmission power transmitted from the radio base station;
A history of the amount of change in timing for transmitting data to the radio base station is recorded, and a monitoring unit that monitors the accumulated value of the recorded amount of change,
An adjustment unit that converts a control value instructing a decrease in transmission power out of the received control values into a control value instructing an increase in transmission power based on a comparison result between the accumulated value and a first threshold; ,
Comprising
A wireless communication system.

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