JPH0758690A - Transmission power control method - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a transmission power control method, and is capable of sufficiently following a fast and deep drop in the received electric field strength at a base station, and also capable of performing transmission power control with high accuracy and a wide dynamic range. The purpose is to provide a power control method. In a transmission power control method in a communication system in which the transmission power of a mobile station 2 is remotely controlled based on a reception input of a base station 1, the mobile station 2 detects a signal related to its own transmission power and The control step width of the own transmission power by the remote control of the base station 1 is changed according to the comparison result of the signal relating to the transmission power and the predetermined threshold. Alternatively, the mobile station 2 detects the rate of change of the signal related to its own transmission power, and changes the control step width of the transmission power by remote control of the base station 1 according to the detected rate of change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power control system, and more particularly to a transmission power control system in a communication system for remotely controlling the transmission power of a mobile station based on a reception input of a base station. In digital communication, development of a communication system having high frequency utilization efficiency is expected, and among them, the direct sequence code division multiple access (DS / CDMA) system is regarded as a promising system capable of realizing a large capacity of communication. When this DS / CDMA system is applied to mobile communication,
A so-called near-far problem occurs due to the difference in distance between the mobile station and the base station, but in order to solve this problem, it is essential to control the transmission power with high accuracy and a wide dynamic range.

[0002]

2. Description of the Related Art FIG. 11 shows an example under the DS / CDMA system.
In the figure, 1 is a base station (B
S), 2₁~ 2₃Is a mobile station (MS). Of FIG.
In (A), the mobile station 2₁~ 2₃From base station 1 respectively
Distance d₁~ D ₃Position, where d₁<D₂<D
₃Is.

In FIG. 11B, the base station 1 moves.
Station 2₁~ 2₃Transmission data TD addressed to₁~ TD₃Each unique
Spread code H₁~ H₃Spread spectrum and spread
Data TDB₁~ TDB₃And send them at the same time.
Believe. On the other hand, mobile station 2₁Then received spread data RD
B₁Spread code H₁Despread by and receive data RD ₁
To decrypt. In this case, the mobile station 2₁Received by the
Data RDB₁Is other diffusion data RDB₂, RDB₃By
However, these noises are spread code H₁
Is not despread by some, the spread data RDB₁But
As long as it has relatively sufficient received power, received data
RD₁Can be decrypted correctly. Mobile station 2₂, 2₃about
Is also the same. In addition, distant mobile station 2₃Then diffusion data R
DB₃Received power decreases, but other spread data RD
B₁, RDB₂Similarly, the reception power of
Signal data RD₃Can be decrypted correctly.

[0004] In (C) of FIG. 11, the mobile station 2 ₃ spectrally spreads to form a spread data TDB ₃ the transmission data TD ₃ destined base station 1 by the spreading code H _3, which in a predetermined transmission power Send. Now, assuming that the transmission powers of the mobile stations 2 _{1 to} 2 ₃ are constant, the mobile stations 2 ₁ and 2 ₂ also transmit the spread data TDB ₁ and TDB ₂ at the same transmission power at the same time. However, in the base station 1, since the distances from the mobile stations 2 ₁ to 2 ₃ are in the relationship of d ₁ <d ₂ <d ₃ , the reception power of each spread data is RDB ₁ > RDB ₂ > RDB ₃ . Get involved. Therefore, the despread data RD ₃ of the distant mobile station 2 ₃ may not be decoded correctly.

Therefore, in the mobile communication in the DS / CDMA system, the base station 1 monitors the reception inputs from the mobile stations 2 ₁ to 2 ₃ and at the same time, the mobile station 2 makes the reception inputs in the base station 1 uniform. and remotely controlling the transmission power of ₂₁ to _3. FIG. 12 is a diagram showing a configuration of a conventional transmission power control system. In the figure, 1 is a base station (BS), 11 is a transmission / reception shared unit, 12 is a spread modulation unit, 13 is a despread demodulation unit, and 14 is a communication control unit. , 15 line controller, 2 ₁ a mobile station (M
S), 21 is a receiver (R), 22 is a microphone (M), 2
3 is a baseband processing unit (BBP), 24 is a codec (CODEC), 25 is a communication control unit (CCU) by the DS / CDMA system, 26 is a spread modulation unit, 27 is a variable attenuator (ATT), and 28 is a transmission amplifier ( TXA), 2
9 is an antenna common part (C), 30 is a receiving amplifier (RF
A), 31 is a despreading demodulation unit, 32 is a console unit for dial operation, 33 is a mobile station control unit, and 33 ₁ is a transmission power control unit, an up / down counter (U / DCT).
R) and 34 are D / A converters (D / A).

The transmission data TD ₁ of the talker on the other side input from the line CH ₁ is spectrum-spread by the spread modulator 12 of the base station 1 and further converted into the reception data RD ₁ by the despread demodulator 31 of the mobile station 2 _1. It is despread and output to the receiver 21. On the other hand, the transmission data TD ₁ of the microphone 22 is the mobile station 2 ₁
The spectrum spread with a spreading modulator 26, is further despread to reception data RD ₁ despreading demodulator 13 of the base station 1, is outputted to the line CH _1.

In this state, the line controller 15 of the base station 1
Is the reception input DS of the mobile station 2 ₁ via the communication control unit 14.
₁ (that is, received electric field strength RSSI ₁ , desired signal-to-interference signal ratio SIR ₁ , instantaneous bit error rate BER _1, etc.) and monitor the received input DS ₁ from the mobile station 2 ₁ to a desired constant value. , The control command PCC ₁ for adjusting the transmission power is included in the transmission data TD ₁ at predetermined intervals and transmitted to the mobile station 2 ₁ .

By the way, generally, in urban areas,
Multiple waves with different propagation paths due to the influence of structures such as shapes and buildings
Thought that they interfered with each other and a standing wave was generated on the road.
To be Therefore, the mobile station 2₁Is running,
Reciprocal of wavelength of standing wave and mobile station 2 ₁Proportional to the running speed of
Fading occurs periodically. On the contrary, movement during running
Station 2₁Similarly, the radio waves emitted from the
Through to the base station 1 and fading in the base station 1
Generate.

FIG. 13 is a timing chart of conventional transmission power control. The line control unit 15 of the base station 1 outputs a control command PCC ₁ = 1 when detecting a drop of the received electric field strength RSSI ₁ ′ from a desired value, for example. As a result, in the mobile station 2 ₁ , the count value of the counter 33 ₁ (hereinafter also referred to as a control voltage) VC ₁ increases, the attenuation amount of the variable attenuator 27 decreases, and the transmission power increases accordingly. Further, the base station 1 outputs the control command PCC ₁ = 0 when detecting an increase in the received electric field strength RSSI ₁ ′ from the desired value. As a result, in the mobile station 2 ₁ , the control voltage VC ₁ drops, the attenuation amount of the variable attenuator 27 increases, and the transmission power decreases accordingly. Therefore, the received electric field strength RSS
When the change of I ₁ ′ is relatively gentle, the transmission power is completely controlled, and the actual reception electric field strength RSSI ₁ in the base station 1 is kept substantially constant.

However, when the received electric field strength RSSI ₁ ′ of the base station 1 drops rapidly due to fading or the like,
In the conventional method in which the transmission power is always controlled with a constant control step width by receiving the control command PCC ₁ , the control of the transmission power cannot catch up, and for this reason, there is an actual drop in the field strength where the change amount is large. Received field strength RSS
I ₁ was greatly depressed as shown.

If the transmission power control step width is always made large, it is possible to follow the deep drop in the received electric field strength RSSI ₁ ′, but conversely there is a transmission power control error in the normal case. It becomes large, resulting in a decrease in subscriber capacity. For example, decrease the subscriber capacity by 1
To reduce it to 0% or less, the transmission power control error should be 0.5 dB.
It is said that the smaller the control step width is, the better because there are computer simulation results that it is necessary to make the following.

A method of increasing the transmission rate of the control command PCC can be considered, but this is not preferable because it reduces the data communication capacity. Incidentally, one concrete proposal in the past is 1 command / 1.25 ms and 0.5 dB / 1 command (QALCOMM Co., Ltd.), but it was difficult to follow fast Rayleigh fading with this.

[0013]

As described above, in the conventional transmission power control system, the mobile station always controls the transmission power with a constant control step width by receiving the control command. There was an inconvenience that it was not possible to follow deep depressions with high strength.

An object of the present invention is to propose a transmission power control system capable of sufficiently following a fast and deep drop in the received electric field strength at a base station and performing transmission power control with high accuracy and a wide dynamic range. .

[0015]

The above problems can be solved by the structure shown in FIG. That is, the transmission power control method of the present invention (1) is a transmission power control method in a communication system in which the transmission power of the mobile station 2 is remotely controlled based on the reception input of the base station 1. The signal related to the power is detected, and the control step width of the own transmission power under the remote control of the base station 1 is changed according to the comparison result of the detected signal related to the transmission power and the predetermined threshold value.

The above problem can be solved by the structure of FIG. That is, in the transmission power control method of the present invention (5), in the transmission power control method in the communication system in which the transmission power of the mobile station 2 is remotely controlled based on the reception input of the base station 1, the mobile station 2 transmits its own transmission power. The rate of change in the signal related to power is detected, and the control step width of the transmission power by remote control of the base station 1 is changed according to the detected rate of change.

[0017]

In FIG. 1A, the transmission data TD of the mobile station 2 is received by the base station 1. In base station 1, mobile station 2
In addition to detecting a received input from the device (for example, received electric field strength), a control command PCC corresponding to a predetermined control step width of the transmission power is transmitted to the mobile station 2 at constant intervals in order to keep the received input constant. In response to this, the mobile station 2 detects a signal VC related to its own transmission power (for example, a control signal of its own transmission power) VC, and shows the result of comparison between the detected signal VC related to transmission power and a predetermined threshold value VTH. In response, the control step width of the transmission power of itself by receiving the control command PCC from the base station 1 is changed.

Thus, for example, in a portion where the received electric field strength in the base station 1 varies greatly (that is, in a portion where the signal VC related to the transmission power in the mobile station 2 varies greatly),
In the mobile station 2, the control step width of the transmission power per command of the received control command PCC is changed to a large one, and the portion in which the fluctuation of the received electric field strength in the base station 1 is small (that is, the transmission power in the mobile station 2 is In the part where the fluctuation of the signal VC related to is small), in the mobile station 2,
The control step width of the transmission power per command of the received control command PCC is returned to normal. Therefore, the base station 1
The received input can be kept constant with high accuracy regardless of the depth of fading at.

Preferably, the mobile station 2 is responsive to the result of comparison between the detected signal relating to the transmission power and a plurality of predetermined thresholds.
The control step width of its own transmission power by remote control of the base station 1 is changed to a plurality of steps. As a result, the reception input at the base station 1 is kept constant with higher accuracy. Further, preferably, the mobile station 2 automatically sets a predetermined threshold value based on a value corresponding to the moving average of a signal related to its own transmission power. As a result, the reception input at the base station 1 is kept constant with high accuracy over a wide dynamic range.

Preferably, the mobile station 2 detects the maximum value and the minimum value of the signal relating to its own transmission power, and automatically sets a predetermined threshold value based on the detected maximum value and minimum value. . As a result, the reception input at the base station 1 is kept constant with high accuracy over a wide dynamic range. In FIG. 1B, the transmission data T of the mobile station 2 is transmitted.
D is received by the base station 1. The base station 1 detects a reception input from the mobile station 2 (for example, reception electric field strength), and in order to keep the reception input constant, a control command PCC corresponding to a predetermined control step width of transmission power is set at regular intervals. Transmit to mobile station 2. Receiving this, the mobile station 2 detects the rate of change of the signal VC related to its own transmission power (for example, the control signal of its own transmission power) VC, and from the base station 1 in accordance with the detected rate of change. The control step width of the own transmission power by the reception of the control command PCC is changed.

Thus, for example, in a portion where the received electric field strength in the base station 1 fluctuates rapidly (that is, in a portion where the signal VC related to the transmission power in the mobile station 2 fluctuates rapidly), the control command received by the mobile station 2 is received. The control step width of the transmission power per command of the PCC is changed to a large one, and the portion where the fluctuation of the received electric field strength in the base station 1 is slow (that is, the signal VC related to the transmission power in the mobile station 2)
In the part where the fluctuation of (1) is slow), the mobile station 2 normalizes (or changes to a smaller one) the control step width of the transmission power per command of the received control command PCC.
Therefore, regardless of the fading speed in the base station 1, the received input can be kept constant with high accuracy.

Preferably, the mobile station 2 detects the rate of change in transmission power based on the number of times the signal relating to its own transmission power crosses a predetermined reference value during a predetermined time.

[0023]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 2 is a diagram showing the configuration of the transmission power control system of the embodiment. In FIG. 2, reference numeral 3 is a transmission power control unit of various embodiments whose details will be described later with reference to FIGS. The configuration and operation of the other parts of FIG. 2 are the same as those described with reference to FIG. 12, so description thereof will be omitted. As described above, the transmission power control method according to the present invention can be realized with a simple configuration without making a large change to the existing communication device and its power control method.

FIG. 3 illustrates the transmission power controller of the first embodiment.
3 is a diagram showing the transmission power control of the first embodiment.
Part 3₁Is an up-down counter (CTR), 3₂Is
Variable frequency divider (1 / M), 3₃Is a low-pass filter (LP
F), 3_FourIs an adder, 3_FiveIs a comparator (CMP)
is there. In FIG. 3A, the up / down counter 3
₁Is a 1-bit control command PC sent from the base station 1.
C₁Is PCC₁When = 1, the count clock at that time
Counts up according to the signal CCK, and also PCC₁=
When it is 0, it follows the count clock signal CCK at that time.
To count down. Low pass filter 3₃Is up
Down counter 3₁Count value (hereinafter, both control voltage
Call) VC₁Of the control voltage VC₁Nodaira
Voltage equalizer VC_1aIs output. Adder 3_FourIs this average voltage V
C_1aIs a predetermined value ΔVC₁(Or -ΔVC₁But good)
Threshold voltage VTH₁To form. Comparator 3_FiveIs
Control voltage VC₁And threshold voltage VTH ₁In comparing with
Than if VC₁> VTH₁₁When, the control signal C = 1
Output, and the variable divider 3₂Is the control command PC
C₁2 or more count clocks for each received
Output a clock signal CCK. Therefore, up in this case
Down counter 3₁Is PCC₁= ± 2 depending on 1/0
Do more than und. Also VC₁≤ VTH₁At the time of control
The signal C = 0 is output, which allows the variable frequency divider 3₂Is control
Command PCC₁About the reception of each
To output one count clock signal CCK. Obey
Up-down counter 3 in this case₁Is PCC₁=
Count ± 1 according to 1/0.

[0025] in FIG. 3 (B), the the mobile station 2 ₁ is connected to the base station 1, the control of the transmission power by the base station 1 is started, for example, the control voltage VC ₁ of the mobile station 2 ₁ is as illustrated 0 Alternatively, a rapid increase is started from the predetermined value toward the desired value in the base station 1. Further, the average voltage VC _1a starts to rise following the rise of the control voltage VC ₁ . Then, when the reception input at the base station 1 becomes an appropriate reception input according to the distance d ₁ between the base station 1 and the mobile station 2 ₁ , the rise of the control voltage VC ₁ is stopped, and the control voltage VC ₁ after that becomes the base station 1. Changes promptly in response to the transmission of the control command PCC ₁ according to the fading. In this case, when the mobile station 2 ₁ further approaches the base station 1 due to the traveling of the mobile station 2 ₁ ,
In response to this, the reception input in the base station 1 gradually increases, and in response to this, the transmission power of the mobile station 2 ₁ , that is, the reference level of the control voltage VC ₁ gradually decreases. Further, the average voltage VC _1a of the output of the low pass filter 3 ₃ also follows this and gradually decreases. Therefore, an appropriate threshold voltage VTH ₁ can be provided over a wide dynamic range.

FIG. 4 is a timing chart of the transmission power control of the first embodiment. FIG. 4 shows that when VC ₁ ≤VTH ₁ , the control voltage VC ₁ is changed by ± 1 control step width according to the input of the control command PCC ₁ = 1/0 at that time, and when VC ₁ > VTH ₁ Shows a specific example in which the control voltage VC ₁ is changed by ± 2 control step width in response to the input of the control command PCC ₁ = 1/0 at that time. As a result of such control, the drop in the actual received electric field strength RSSI _{1 at} the base station 1 is significantly reduced compared to the conventional case of FIG.

Since the control command PCC ₁ is 1 bit in this example, when the control command transmission cycle is T, the signal of PCC ₁ = 1/0 is actually input at times t ₂ and t _4. To be done. Figure 5 is a diagram for explaining the transmission power control unit of the second embodiment, 3 transmission power control unit of the second embodiment in FIG, _3-6 adders, 3 ₇ comparators (CM
P).

In FIG. 5A, in this second embodiment,
Is the first threshold voltage VTH₁₁= VC_1a+ ΔVC₁₁And the second
Threshold voltage VTH₁₂= VC_1a+ ΔVC₁₂(> ΔVC₁₁)
And form. Comparator 3_FiveIs VC₁And VTH
₁₁Compare with and VC₁> VTH₁₁When is C₁Output = 1
And VC₁≤ VTH₁₁When is C₁= 0 is output. Also
Comparator 3₇Is VC₁And VTH₁₂Compare with and VC
₁> VTH₁₂When is C ₂= 1 is output and VC₁≤ VTH
₁₂When is C₂= 0 is output. Variable frequency divider 3₂Is the control signal
Issue C₁, C₂Depending on the combination of (C₁, C₂) =
Normal clock rate when (0,0), (C₁，
C₂) = (1,0) is faster than normal clock rate
To, (C₁, C₂) = (1,1) more than the above
The count clock signal CCK with a high clock rate is
Up-down counter 3₁Supply to.

In FIG. 5B, in this example,
The second threshold voltages VTH ₁₁ and VTH ₁₂ change in the manner as shown. The control voltage VC ₁ in this case is V
In the case of C ₁ ≤VTH ₁₁ and VC ₁ ≤VTH ₁₂ , it changes with a normal control step width, and VC ₁ > VTH ₁₁ and VC ₁ ≤VT
In the case of H ₁₂ , it changes with a control step width larger than usual, and in the case of VC ₁ > VTH ₁₁ and VC ₁ > VTH ₁₂ , it changes with a control step width larger than the above. Therefore,
Optimal control of the transmission power that matches the fading characteristics such that the fading starts / ends changes relatively gently and the central part changes sharply can be performed. Of course, the threshold voltage may be set to 3 or more.

FIG. 6 is a timing chart of the transmission power control of the second embodiment. FIG. 6 shows each control command PCC ₁
Control voltage VC ₁ at that time, VC ₁
In the case of ≤VTH ₁₁ , VC ₁ ≤VTH ₁₂ , the control step width is changed by ± 1 so that VC ₁ > VTH ₁₁ , VC ₁ ≤VTH.
_In case of ₁₂ , change by ± 2 control step width and VC ₁ >
In the case of VTH ₁₁ and VC ₁ > VTH ₁₂ , one specific example in the case of changing by ± 3 control step width is shown. As a result of such control, the actual received electric field strength RS at the base station 1
The drop in SI ₁ is further reduced as compared with the first embodiment shown in FIG.

FIG. 7 is a diagram for explaining the transmission power control unit of the third embodiment, 3 is a transmission power control unit of the third embodiment in FIG, 3 _8, 3 ₉ comparator (CMP), the fourth control peak detector voltage VC ₁ (PD), 4 ₁ a comparator (CMP), 4 ₂ register (REG), 5 the bottom detector of the control voltage VC ₁ (BD), 5 ₁ a comparator (CMP), 5 Reference numeral ₂ is a register (REG), and reference numeral 6 is a calculator of the threshold voltage VTH ₁ .

In FIG. 7A, the peak detector 4
Is the comparator 4₁Is the current control voltage VC₁And cash register
Star 4₂Peak control voltage VC held by_1max(However
Then, at the beginning, compare with the minimum value 0 preset)
Than VC₁> VC_1maxWhen is register 4₂At the moment
Control voltage VC₁To load. Thus register 4 ₂
Is the control voltage VC₁Peak value VC_1maxTo detect and hold.

In the bottom detecting section 5, the comparator 5 ₁ compares the present control voltage VC ₁ with the past bottom control voltage VC _1min held by the register 5 ₂ (however, the maximum value FF is preset at the beginning). , VC ₁ <VC
_{At 1 min} , the control voltage VC ₁ at the present time is loaded into the register 5 ₂ . In this case, the comparator 3 ₉ Control voltage V
C ₁ and the average voltage VC _1a are compared, and VC ₁ <VC
Biasing the data loaded into the register 5 ₂ when satisfying the _1a. Thus, the register 5 ₂ detects and holds the bottom value VC _1min of the control voltage VC ₁ .

Then, the calculation unit 6 forms the optimum threshold voltage VTH ₁ based on VC _1max and VC _1min . Furthermore,
The comparator 3 ₈ controls the control voltage VC ₁ and the threshold voltage VTH ₁
By comparing the bets, when the VC _1> VTH ₁ outputs a control signal C = 1, when VC ₁ ≦ VTH ₁ outputs C = 0. The variable frequency divider 3 ₂ supplies a count clock signal CCK having a normal clock rate to the up / down counter 3 ₁ when C = 0, and a count clock signal CCK having a faster clock rate than normal when C = 1. Is supplied to the up / down counter 3 ₁ .

In FIG. 7B, VC_1maxAnd VC
_{1 min}VTH according to changes in₁Varies optimally. This example
Then VTH₁= (VC_1max+ VC_{1 min}) / 2
However, it is not limited to this. Also, VC_1maxAnd VC_{1 min}And to
Based on a plurality of threshold voltages VTH ₁₁~ VTH_1nGenerate
Is also good. FIG. 8 is a timing of transmission power control of the third embodiment.
It is a chart.

FIG. 8 shows each control command PC from the base station 1.
When C ₁ is received, control voltage VC ₁ is changed to VC ₁ ≦ V
When TH ₁ is changed by the normal ± 1 control step width, V
When C ₁ > VTH ₁ , the case is shown in which the control step width is changed by ± 3 which is larger than usual. As a result of such control, the drop in the actual received electric field strength RSSI _{1 at} the base station 1 is significantly reduced compared to the conventional case of FIG.

As the magnitude of (VC _1max -VC _1min ) increases, the control step width ratio becomes 1: 2, 1: 3.
You may change it to 1: 4. FIG. 9 is a diagram for explaining the transmission power control unit of the fourth embodiment. In FIG. 9, 3 is the transmission power control unit of the fourth embodiment, 3 ₁₀ is a comparator (CMP),
7 is a counter (CTR), 8 is a register (REG), 9
Is a timing generator (TG).

In FIG. 9A, the comparator 3 ₁₀
Compares the control voltage VC ₁ with the average voltage VC _1a so that when the clock signal CK is satisfied when VC ₁ > VC _1a
= 1 is output. The counter 7 is reset by the timing generator 9 in a predetermined cycle, and counts the subsequent rising edge of each clock signal CK and outputs a corresponding count value F. The register 8 holds the count value F when each predetermined period has elapsed. The variable frequency divider 3 ₂ supplies a count clock signal CCK having a normal clock rate to the up-down counter 3 ₁ according to the content of the count value F when the count value F is small, and increases as the count value F increases. A count clock signal CCK having a faster clock rate than usual is supplied to the up / down counter 3 ₁ .

In FIG. 9B, the traveling speed of the mobile station 2 ₁ increases from a certain period T _i to T _{i + 1} .
As a result, the frequency of Rayleigh fading (that is, the rate of change of the received electric field strength) increases, and the count value F also increases. Therefore, if the control step width of the control voltage VC ₁ is increased according to the increase of the count value F, the actual received electric field strength RSSI ₁ in the base station 1 can be controlled flat.

FIG. 10 is a timing chart of the transmission power control of the fourth embodiment. In FIG. 10, when each control command PCC ₁ is received from the base station 1, the control voltage VC ₁ is changed according to the count value F held in the register 8 at that time.
Shows a specific example in which is changed by ± 1.5 control step width. By such control, the drop of the actual received electric field strength RSSI _{1 at} the base station 1 is significantly reduced as compared with the conventional case of FIG.

In the above embodiment, the mobile station 2 ₁ controls the control voltage VC for applying its own transmission power to the variable attenuator 27.
However, the detection is not limited to this. The signal relating to its own transmission power may be a signal formed by any method as long as it can detect its own transmission power. Further, in the above embodiment, the control step width of the transmission power of the mobile station 2 ₁ is controlled by the number of clocks added to the up / down counter 3 ₁ , but it is not limited to this. The control step width of the transmission power may be variably controlled by any method.

In the above embodiment, the control voltage VC₁Transfer of
Dynamic average voltage VC_1aIs a predetermined value ΔVC₁Threshold by adding
Voltage VTH₁However, it is not limited to this. Threshold voltage V
TH ₁May be a fixed predetermined value. In addition, the above
In the example, a plurality of characteristic examples are shown, but the idea of the present invention is
Various changes of each component and each
It is possible to make various changes in the combination of components.
is there.

[0043]

As described above, according to the present invention, the mobile station 2 determines the rate of change in the signal related to its own transmission power or according to the result of comparison between the signal related to its own transmission power and a predetermined threshold value. Accordingly, the control step width of its own transmission power by remote control of the base station 1 is changed, so that the transmission rate of the control command for power adjustment from the base station 1 can be increased even if fast Rayleigh fading occurs. Without, the actual receive input at the base station 1 can be kept as desired and precise. Therefore, it is possible to solve the near-far problem that is a problem in mobile communication by the DS / CDMA system, and it is possible to realize a communication system with high frequency utilization efficiency.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a configuration of a transmission power control system according to an embodiment.

FIG. 3 is a diagram illustrating a transmission power control unit according to the first embodiment.

FIG. 4 is a timing chart of transmission power control according to the first embodiment.

FIG. 5 is a diagram illustrating a transmission power control unit according to a second embodiment.

FIG. 6 is a timing chart of transmission power control of the second embodiment.

FIG. 7 is a diagram illustrating a transmission power control unit according to a third embodiment.

FIG. 8 is a timing chart of transmission power control of the third embodiment.

FIG. 9 is a diagram illustrating a transmission power control unit according to a fourth embodiment.

FIG. 10 is a timing chart of transmission power control according to the fourth embodiment.

FIG. 11 is a diagram illustrating an example of mobile communication under the DS / CDMA system.

FIG. 12 is a diagram showing a configuration of a conventional transmission power control method.

FIG. 13 is a timing chart of conventional transmission power control.

[Explanation of symbols]

 1 base station 2 mobile station

Claims (6)

[Claims] 1. The transmission power of a mobile station (2) is set to a base station (1).
In a transmission power control method in a communication system for remote control based on the reception input of the mobile station (2), the mobile station (2) detects a signal related to its own transmission power, and detects a signal related to the detected transmission power and a predetermined threshold value. A transmission power control method characterized by changing a control step width of its own transmission power by remote control of a base station (1) according to a comparison result. 2. The mobile station (2) determines a control step width of its own transmission power by remote control of the base station (1) according to a result of comparison between a signal relating to the detected transmission power and a plurality of predetermined thresholds. The transmission power control method according to claim 1, wherein the transmission power control method is changed in a plurality of steps. 3. The transmission power according to claim 1, wherein the mobile station (2) automatically sets a predetermined threshold value based on a value corresponding to a moving average of a signal relating to its own transmission power. control method. 4. The mobile station (2) detects a maximum value and a minimum value of a signal related to its own transmission power, and automatically sets a predetermined threshold value based on the detected maximum value and minimum value. The transmission power control system according to claim 1 or 2, characterized in that. 5. The transmission power of the mobile station (2) is set to the base station (1).
In a transmission power control method in a communication system for performing remote control based on the reception input of the mobile station, the mobile station (2) detects a rate of change of a signal related to its own transmission power and, in accordance with the detected rate of change, A transmission power control method characterized by changing a control step width of transmission power by remote control of a base station (1). 6. The mobile station (2) is characterized in that the mobile station (2) detects the rate of change in transmission power based on the number of times a signal related to its own transmission power crosses a predetermined reference value during a predetermined time. Item 5. Transmission power control method.