JPH10145293A - Transmission power controlling method and communication equipment of cdma mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a transmission power control error by generating and arranging a transmission power control signal, based on the signal level of a measured communication signal in a timing that arranges a transmission power control signal in a transmission signal to a 1st communication equipment. SOLUTION: A base station receiving slot measures the power of an up transmission channel receiving signal synchronously with the slot, compares receiving power with a timing immediately prior to a transmission power control symbol layer in a base station transmission slot 1 with the power of system requirement and generates a transmission power control symbol 33. A base station transmission slot inserts the generated transmission power control symbol 33 into the slot 1 and transmits it to a mobile station. A pilot channel transmits a pilot symbol. A mobile station receiving slot detects the pilot symbol as a reference phase signal and demodulates the symbol 33. A mobile station transmission slot decides the value of the symbol 33, without waiting for the next slot front and increases and reduces transmission power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a (Direct Sequence / Code Division Multiple Access) mobile communication system, and more particularly, to a control method and a communication device for reducing a transmission power control error in transmission power control.

[0002]

2. Description of the Related Art A DS / CDMA mobile communication system is a communication system in which a plurality of users use the same frequency band.
Therefore, especially in the uplink, signals from each user become asynchronous, and signals from other users interfere (noise).
There is a problem that becomes. Therefore, in order to increase the subscriber capacity per cell, the reception power of each mobile station or the ratio of the desired signal power to the interference signal power (Signal-to-Interference Ratio: SIR) is increased on the base station receiving side. Transmission power control is performed so as to be constant at a required value determined by the system.

As a conventional example 1, a transmission power control method described in “7.1.3.1.7 Power Control Subchannel” on page 13 to page 15 of TIA / EIA / IS-95-A is described. This is shown below using the drawings.

FIG. 1 shows a procedure of uplink closed-loop transmission power control and a method of generating transmission power control symbols.

[0005] (Step 1): The mobile station transmits a data signal to the base station through an uplink transmission channel. The transmission power at this time is Tx_Power [dB].

(Step 2): The base station measures the power of the data signal received from the mobile station. Received power (Rx_Pow
er [dB]) is smaller than the system required power (Power_Req [dB]), the transmission power control symbol (TPC: Trans)
mission power control) is set to “0”, and when equal or larger, TPC is set to “1”. The TPC is placed in the data signal and transmitted on the downlink transmission channel to the mobile station.

[0007] Further, the base station transmits pilot symbols on a pilot channel. The pilot channel is a channel common to all mobile stations within the jurisdiction of the base station. The pilot symbol is a reference phase signal used for synchronous detection of a data signal received by the mobile station.

(Step 3): The mobile station detects the received signal using the pilot symbol as a reference phase signal and
Obtain a PC (transmission power control symbol). TPC is "0"
Then, the transmission power at the next transmission (Tx_Power [dB]) is (Tx
_Power [dB] + Step_Power [dB], if TPC is “1”, change Tx_Power [dB] to (Tx_Power [dB] -Step_Power [dB])
Update to Here, Step_Power [dB] is a transmission power control width.

As described above, closed-loop transmission power control is performed so that the reception power at the base station becomes the power required for the system.

FIG. 2 shows a transmission signal slot format in a downlink transmission channel from a base station to a mobile station. The downlink transmission channel is a data signal 32 of 24 symbols.
The transmission power control symbol (TPC) 33 is arbitrarily located within 16 symbols from the head in the data signal 32. TPC consists of one symbol.

Referring to FIG. 3, the timing of the transmission power control of the conventional example 1 will be described based on the slot configuration. The shift between the transmission slot and the reception slot that occurs during communication between the base station and the mobile station is not shown in the figure because it is smaller than the slot length.

In the base station receiving slot, during slot 0, the power of a signal received from the mobile station is measured, and the measured received power (Rx_Power [dB]) is used as the power required for the system (Power_Power).
Req [dB]) and transmit power control symbol (TPC)
33 is generated. TPC is as shown in FIG. In this case, Power_Req [dB] ≦ Rx_Power [dB], and TP
C = 1 is generated.

In the base station transmission slot, the transmission power control symbol 33 is inserted into slot 1 in the downlink transmission channel.
And transmit it to the mobile station. Transmission power control symbol 33
Are scrambled and inserted at positions within 16 symbols from the beginning of the slot. Also, a pilot symbol is transmitted on a pilot channel.

In the mobile station reception slot, the transmission power control symbol (slot 1) of the downlink transmission channel and the pilot symbol of the pilot channel are received, the pilot symbol is detected as a reference phase signal, and the transmission power control symbol 33 is demodulated. .

In the mobile station transmission slot, in slot 2, the value of the transmission power control symbol 33 is determined, and the transmission power is controlled by increasing or decreasing the transmission power. Here, TPC = 1 is received, and the transmission power is set to −Step_Power [dB].
doing.

As a second conventional example, IEICE Technical Report RCS95-80 (October 1995) pp. 13-18 "Transmission experiments on mobile radio access using coherent multicode DS-CDMA" (Yukihiko Okumura) , Akihiro Tou, Tomohiro Toi, Koji Ohno, Fumiyuki Adachi).

FIG. 4 shows a procedure of uplink closed-loop transmission power control and a method of generating a transmission power control symbol in Conventional Example 2. The difference from FIG. 1 lies in that there is no independent pilot channel and that SIR is used as an index for transmission power control.

Specifically, in step 2, the base station measures the SIR of the data signal from the mobile station and compares it with SIR_Req (SIR required by the system) to generate a transmission power control symbol TPC. Instead of providing an independent pilot channel, a pilot symbol is placed at the beginning of a slot and a TPC is placed at the beginning of a data signal and transmitted to the mobile station (such a slot configuration is called "pilot symbol interpolation type slot"). For other control methods, see FIG.
The SIR at the base station is the same as the SIR required by the system.
The closed loop transmission power control is performed so that

It should be noted that there is no essential difference between using received power or SIR as an index for power control, and it can be said that they are equivalent from the viewpoint of observing the signal level of a communication signal. The interference signal power is composed of thermal noise and interference power, which take a stable value, and the desired signal power fluctuates in the same manner as the fluctuation of the received power.

FIG. 5 shows the format of a transmission signal slot. A pilot symbol 31 (2 symbols) is located at the beginning of the slot, and a transmission power control symbol 33 (1 symbol) is located immediately after the pilot symbol 31 and at the beginning of the data signal 32.

Referring to FIG. 6, the timing of the transmission power control of the conventional example 2 will be described based on the slot configuration. As in FIG.
The shift between the transmission slot and the reception slot that occurs during communication is omitted.

In the base station receiving slot, during slot 0, the measured SIR and SIR_Req are compared to generate a transmission power control symbol (TPC) 33.

In the base station transmission slot, pilot symbols 311 are inserted into slot 1 in the downlink transmission channel.
Immediately after the transmission power control symbol 33 is inserted and transmitted to the mobile station.

In the mobile station reception slot, the transmission power control symbol inserted in slot 1 is replaced with two pilot symbols 311A located at the beginning of slot 1 and slot 2.
, And 312A, a pilot symbol obtained by performing primary interpolation on the two is detected as a reference phase signal, and the transmission power control symbol 33A is demodulated.

In the mobile station transmission slot, in slot 3, the value of the transmission power control symbol 33 is determined, and the transmission power is controlled by increasing or decreasing the transmission power.

[0026]

In the uplink transmission power control in the prior art 1 or 2, the base station measures the reception power or SIR and generates a transmission power control symbol (TP
This is performed by notifying the mobile station by C) and detecting the TPC by the mobile station and controlling the transmission power. However,
When the received power fluctuates with time due to fading or the like, a large transmission power control error occurs if the delay from power (or SIR) measurement at the base station to transmission power control at the mobile station is large.

For example, in the transmission power control method of the first conventional example shown in FIG. 3, (1) the delay at the base station from the measurement of the reception power to the transmission of the transmission power control symbol to the mobile station is one.
1, (2) There is a delay 12 on the mobile station side from the reception / demodulation of the transmission power control symbol to the update of the transmission power.

Further, in the transmission power control method of the second conventional example shown in FIG. 7, (1) a delay at the base station from the measurement of the SIR to the transmission of the transmission power control symbol to the mobile station 11, (2) In addition to the delay 12 on the mobile station side from the demodulation of the transmission power control symbol to the updating of the transmission power 12, in addition to (3) the detection using two pilot symbols in the pilot symbol interpolation type slot, A delay 13 occurs until a transmission power control symbol is demodulated with a signal obtained by receiving and linearly interpolating one pilot symbol.

An object of the present invention is to reduce a transmission power control error by reducing a delay from the measurement of reception power or SIR to the update of transmission power, which has occurred in the conventional example.

[0030]

In the prior art, the base station measures the channel power or SIR of the received signal from the mobile station for each slot, but in the present invention, the base station measures the received signal asynchronously with the slot. Channel power or SIR
Is measured. With this method, the delay 11 can be reduced.

In the present invention, after demodulating the transmission power control symbol from the base station, the mobile station updates the transmission power without waiting for the head of the next slot, and executes transmission power control. In this way, the delay 12 can be reduced.

Further, with respect to the transmission power control method using the pilot symbol interpolation type slot configuration, in the present invention, the insertion position of the transmission power control symbol is set as backward as possible between the pilot symbols. With this method, the delay 13 can be reduced.

[0033]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 7 illustrates a procedure of uplink closed-loop transmission power control and a method of generating a transmission power control symbol according to the first embodiment of the present invention. Example 1 is a conventional example 1.
This is a method of performing transmission control by using an independent pilot channel in the same manner as described above.

Compared with Conventional Example 1, (1) In step 2, the base station measures the power of the received data signal from the mobile station asynchronously with the slot until immediately before the transmission power control symbol insertion timing, (2) In step 3, the mobile station updates the transmission power without waiting for the beginning of the next slot.

Referring to FIG. 8, the timing of the transmission power control in the first embodiment will be described based on the relationship between the power measurement position and the transmission power control symbol insertion position.

In the base station reception slot, the power of the uplink transmission channel reception signal is measured asynchronously with the slot, and the reception power Rx_Power [dB] at the timing immediately before the insertion of the transmission power control symbol in base station transmission slot 1 is required by the system. The transmission power control symbol 33 is generated by the method shown in FIG.

In the base station transmission slot, the transmission power control symbol 33 generated from the power measurement in the base station reception slot is inserted into slot 1 and transmitted to the mobile station.
In the pilot channel, a pilot symbol is transmitted.

In the case of FIG. 8, since Rx_Power [dB] ≧ Power_Req [dB] at the timing immediately before the transmission power control symbol is inserted in slot 1,
TPC = 1 is generated, and the generated transmission power control symbol 33 is inserted into slot 1 and transmitted to the mobile station.

In the mobile station reception slot, the transmission power control symbol (slot 1) of the downlink transmission channel and the pilot signal of the pilot channel are received, the pilot symbol is detected as a reference phase signal, and the transmission power control symbol 33 is demodulated. .

In the mobile station transmission slot, the transmission power control is executed by determining the value of the transmission power control symbol 33 and increasing or decreasing the transmission power without waiting for the next slot head (in slot 1).

FIG. 9 is a functional block diagram for performing uplink transmission power control according to the first embodiment.

Next, the base station receiving system will be described. The received power is measured by the power measuring unit 22 after despreading and detecting the signal from the mobile station. The base station control system 40 transmits transmission power control symbol transmission timing information (hereinafter referred to as “timing information”) 29 to the transmission power control symbol generation unit 24.
To the multiplexer 41. Timing information 29
In response, the transmission power control symbol generation unit 24 generates the transmission power control symbol 33. The signal after detection is
The demodulation unit 21 outputs the data as reception data.

In the base station transmission system, on the downlink transmission channel, the multiplexer 41 receives the timing information 29 and combines the transmission input data signal 32 to the mobile station and the transmission power control symbol 33 used for transmission power control. With the combined signal 34 and pilot symbol 31 as inputs, each of spreading sections 43A and 43B performs spread spectrum modulation on a pilot channel and a downlink transmission channel,
The transmitting unit 44 transmits the multiplexed signal 36 to the mobile station via the antenna 45.

FIG. 14 shows a more detailed configuration of power measuring section 23 and transmission power control symbol generating section 24 in the base station.
This will be described with reference to FIG.

The power measuring section 22 reduces the noise component of the input detection output by an averaging circuit 25 and outputs a power value for each symbol by a squarer 26. When receiving the timing information 29 from the base station control system 40, the transmission power control symbol generation unit 24 reads the power value measured by the power measurement unit 22 and outputs it to the comparator 28. The comparator 28 compares the read power measurement value with the control target value (Po
wer_Req), and generates and outputs a transmission power control symbol 33.

Here, the averaging circuit 25 is a circuit for performing averaging using a forgetting coefficient corresponding to the length of a slot, and has a configuration capable of outputting each symbol. As a result, it is possible to reduce the influence of the temporary fluctuation of the received power.

FIG. 14 (b) shows the relationship between the timing of power measurement and the transmission power control symbol transmission timing. The power measurement unit 22 outputs a power value to the latch 27 for each symbol. The latch 27 receives the input of the timing information 29 different for each slot, and outputs the power value to the comparator 28. As a result, the transmission power control symbol 33 can be generated asynchronously with the slot.

In FIG. 9, in the mobile station receiving system, receiving section 52 transmits radio signal 37 transmitted from the base station to antenna 5.
1 to receive. In the transmission channel, despreading section 53A outputs the despread signal (data signal 32A and transmission power control symbol 33A) and inputs the signal to synchronous detection section 55. In the pilot channel, the despreading unit 53B
Outputs a pilot symbol as a signal 311A after despreading, and inputs the signal to the synchronous detection unit 55. Synchronous detector 55
Is a transmission power control symbol 33A and a data signal 32 using a pilot symbol 311A as a reference phase signal.
A is detected. The detection output is supplied to the reception data signal 32B and the transmission power control symbol 33 by the demultiplexer 57.
The demodulation unit 58 demodulates the data signal 32B and outputs the data signal 32.

In the mobile station transmission system, the transmission power control section 61 updates the transmission power based on the transmission power control symbol 33 without taking slot synchronization, and the transmission section 62 controls the transmission power for the base station.

Thus, the delay 11 and the delay 12 shown in FIG. 3 are eliminated.

As a second embodiment, FIG. 10 shows a procedure of uplink closed-loop transmission power control using a pilot symbol interpolation type slot configuration and a method of generating transmission power control symbols in the present invention.

In comparison with the conventional example 2, (1) In step 2, the base station measures the SIR of the received data signal from the mobile station asynchronously with the slot until immediately before the transmission power control symbol insertion timing. ) Step 2
, The transmission power control symbol is arranged at the end of the data signal and transmitted to the mobile station. (3) In step 3, the mobile station updates the transmission power without waiting for the head of the next slot. .

FIG. 11 shows a format of a transmission signal slot from a base station to a mobile station in the second embodiment. The slot has a pilot interpolation type slot configuration including a pilot symbol 31 used for detection at the head of the slot and a data signal 32 positioned immediately after the pilot symbol 31. Here, the transmission power control symbol 33
Is located at the end of the data signal. Although the position of the transmission power control symbol 33 is not limited to the last position, it is desirable to place the transmission power control symbol 33 at the end of the slot in order to reduce the control delay.

Referring to FIG. 12, the timing of the transmission power control in the second embodiment will be described based on the relationship between the SIR measurement position and the transmission power control symbol insertion position.

In the base station reception slot, the power of the uplink transmission channel received signal is measured asynchronously with the slot, and the SIR of the uplink transmission channel received signal is the system required SIR.
As compared with SIR_Req, the transmission power control symbol 33 is shown in FIG.
Generated by the method shown in.

In the base station transmission slot, the transmission power control symbol 33 generated by measuring the SIR in the base station reception slot is inserted at the end of the data signal in slot 1 and transmitted to the mobile station.

In the case of FIG. 12, since Rx_SIR ≧ SIR_Req at the timing immediately before transmission power control symbol insertion in slot 1, TPC = 1
Is generated, and the generated transmission power control symbol 33 is
It is inserted into slot 1 and transmitted to the mobile station.

In the mobile station reception slot, pilot symbol 311A located at the head of slot 1 and slot 2
And 312A, the transmission power control symbol 33A located at the end of the slot is immediately detected and demodulated with the pilot symbols obtained by linearly interpolating the two.

In the mobile station transmission slot, the value of the transmission power control symbol 33 is determined without waiting for the head of the next slot (slot 3), and the transmission power is controlled by increasing or decreasing the transmission power.

FIG. 13 is a functional block diagram for performing uplink transmission power control according to the second embodiment.

[0062] The base station receiving system will be described. SIR
Is measured by the SIR measurement unit 23 after despreading and detecting the signal from the mobile station. The base station control system 40 outputs the timing information 29 to the transmission power control symbol generator 24 and the multiplexer 41. However, this timing information 29 is different from the case of the first embodiment in which the position where the transmission power control symbol 33 is inserted is arbitrary. In the second embodiment, the transmission power control symbol 33 is placed at a fixed position, May be sent out. In response to the timing information 29, the transmission power control symbol generation section 24 generates a transmission power control symbol 33. The signal after detection is output by the demodulation unit 21 as received data.

In the base station transmission system, the multiplexer 41
Combines the transmission input data signal 32 to the mobile station, the pilot symbol 31 used for detection, and the transmission power control symbol 33 used for transmission power control in the slot configuration shown in FIG. Spreading section 43 performs spread spectrum modulation with combined signal 34 as input, and transmitting section 44 transmits output signal 36 to mobile station via antenna 45.

FIG. 15 shows a more detailed configuration of SIR measurement section 23 and transmission power control symbol generation section 24 in the base station.
This will be described with reference to FIG.

The SIR measuring section 23 can measure for each symbol, and outputs the SIR measured value to the transmission power control symbol generating section 24. The transmission power control symbol generation unit 24 receives the input of the timing information 29 from the base station control system 40,
The SIR measurement value measured by the R measurement unit 23 is read and the comparator 28
Output to The comparator 28 compares the read power measurement value with a control target value (SIR_Req), and generates a transmission power control symbol 33.

FIG. 15B shows the relationship between SIR measurement and transmission power control symbol transmission timing. The SIR measurement unit 23 outputs the SIR measurement value to the latch 28 for each symbol. The latch 28 receives the input of the timing information 29 having the same timing every time for each slot, and outputs the SIR measurement value to the comparator 28.

In FIG. 13, in the mobile station receiving system, a receiving section 52 receives a radio signal 37 transmitted from a base station via an antenna 51. The signal 39 after despreading in the despreading unit 53 is separated by the demultiplexer 54 into a pilot symbol 31A, a transmission power control symbol 33A and a data signal 32A and input to the synchronous detection unit 55A, which is a reference phase signal. The transmission power control symbol 33A and the data signal 32A are detected using the pilot symbol 31A. Here, the pilot symbols used for the synchronous detection are pilot symbols inserted at the beginning of slot 1 and slot 2 shown in FIG. 11, and are primary-ordered from two of 311A and 312A delayed by one symbol by delay unit 56. Estimate the fading complex envelope using interpolation,
This realizes synchronous detection. The output signal after the detection is supplied to the data signal 32B by the demultiplexer 57.
And the transmission power control symbol 33 and the demodulation unit 58
Demodulates the data signal and outputs it as a data signal 32.

In the mobile station transmission system, the transmission power control unit 61 updates the transmission power based on the transmission power control symbol 33 without performing slot synchronization, and the transmission unit 62 performs transmission power control on the base station. .

As a result, the delay 11, delay 12, and delay 13 shown in FIG. 7 are eliminated.

The present invention is also applicable to downlink transmission power control by exchanging the functions of uplink and downlink.

Also, the present invention measures a signal level of a communication signal for a downlink pilot channel signal in a mobile station and uses a method disclosed in a base station disclosed in Japanese Patent Laid-Open No. 7-38496. The present invention is also applicable to downlink open loop transmission power control for updating transmission power.

[0072]

According to the present invention, the transmission power control error can be reduced by reducing the delay from the measurement of the channel power or the SIR to the execution of the transmission power control. As a result, the subscriber capacity per cell in the DS / CDMA mobile communication system can be increased, or the communication quality can be improved while maintaining the same subscriber capacity.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a closed-loop transmission power control procedure and a method of generating a transmission power control symbol in Conventional Example 1 in a CDMA mobile communication system.

FIG. 2 is a diagram showing a configuration of a base station transmission slot in Conventional Example 1.

FIG. 3 is a diagram showing a slot configuration and functions related to closed-loop transmission power control in Conventional Example 1.

FIG. 4 is a diagram showing a closed-loop transmission power control procedure and a transmission power control symbol generation method in Conventional Example 2 in a CDMA mobile communication system.

FIG. 5 is a diagram showing a configuration of a base station transmission slot in Conventional Example 2.

FIG. 6 is a diagram showing a slot configuration and functions related to closed-loop transmission power control in Conventional Example 2.

FIG. 7 is a diagram illustrating a closed-loop transmission power control procedure and a transmission power control symbol generation method according to the first embodiment in the CDMA mobile communication system.

FIG. 8 is a diagram illustrating a slot configuration and a function related to closed-loop transmission power control in the first embodiment.

FIG. 9 is a functional block diagram illustrating closed-loop transmission power control according to the first embodiment.

FIG. 10 is a diagram illustrating a closed-loop transmission power control procedure and a transmission power control symbol generation method in Embodiment 2 in the CDMA mobile communication system.

FIG. 11 is a diagram illustrating a configuration of a base station transmission slot according to the second embodiment.

FIG. 12 is a diagram illustrating a slot configuration and functions related to closed-loop transmission power control in the second embodiment.

FIG. 13 is a functional block diagram illustrating closed-loop transmission power control according to the second embodiment.

FIG. 14 is a diagram illustrating a configuration of a power measurement unit and a transmission power control symbol generation unit according to the first embodiment.

FIG. 15 is a diagram illustrating a configuration of an SIR measurement unit and a transmission power control symbol generation unit according to the second embodiment.

[Explanation of symbols]

21: base station demodulation unit, 22: power measurement unit, 23: SIR
Measurement unit, 24: transmission power control symbol generation unit, 25: averaging circuit, 26: squarer, 27: latch, 28: comparator, 40: base station control system, 41: multiplexer, 43
... Spreading unit, 44 ... Base station transmitting unit, 45, 51 ... Antenna, 52 ... Mobile station receiving unit, 53 ... Despreading unit, 54, 57
... a demultiplexer, 55 ... a synchronous detector, 56 ... a symbol delay unit, 58 ... a mobile station demodulator, 61 ... a transmission power controller, 62 ... a mobile station transmitter.

Claims (5)

[Claims] 1. A transmission power control method for two-way communication between a first communication device and a second communication device in a CDMA mobile communication system, wherein the second communication device includes the first communication device. The signal level of the communication signal from the communication device is measured at a predetermined timing, and the signal of the measured communication signal at the timing of arranging the transmission power control signal at a predetermined position in the transmission signal to the first communication device A transmission power control method characterized by generating and arranging a transmission power control signal based on a level. 2. A transmission power control method for two-way communication between a first communication device and a second communication device in a CDMA mobile communication system, wherein the first communication device performs a second communication. Receiving the communication signal including the transmission power control signal transmitted from the communication device, and updating the transmission power of the signal to be transmitted to the second communication device at a timing when the demodulation of the received transmission power control signal is completed. A transmission power control method characterized by the above-mentioned. 3. A CDMA mobile communication system using a pilot signal interpolation type slot in which a pilot signal used as a reference phase signal is arranged at the beginning of a transmission slot.
A transmission power control method at the time of bidirectional communication between a first communication device and a second communication device, wherein a transmission power control signal in a transmission signal to the first communication device is set at the end of the transmission slot. It is determined in advance that the transmission power control signal should be fixedly arranged at the tail. Transmission power control method characterized by the above-mentioned. 4. A communication device in a CDMA mobile communication system, comprising: a signal level measuring section for measuring a signal level of a communication signal from another communication device at a predetermined timing; A control system that outputs timing information for arranging a transmission power control signal at a predetermined position, and a signal level of the communication signal output from the signal level measurement unit in response to the timing information output from the control system. A transmission power control signal generation unit that generates a transmission power control signal by comparing with a control target value; and combines the generated transmission power control signal and the transmission data signal in response to the timing information output from the control system. A communication device comprising: 5. A communication system in a CDMA mobile communication system, comprising: a reception system for receiving a communication signal including a transmission power control signal transmitted from another communication system; and a demodulation of the transmission power control signal in the reception system. And a transmission power control unit that updates the transmission power of the signal to be transmitted to the other communication device at the timing when is completed.