JP2000244391A - Transmission power control method in code division multiple access communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission power control method reducing the influence of erroneous control in a CDMA mobile communication system. SOLUTION: The likelihood of a transmission power control signal is calculated 30 based on the transmission power control signal transmitted from a radio base station and the quality of reception. Based on the likelihood, the varying quantity of transmission power is calculated 31 to control the transmission power of a mobile terminal based on the varying quantity. Thus, the mobile terminal is prevented from transmitting with excessive transmission power.

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 method in a mobile communication system, and more particularly, to a code division multiple access (CDMA) system.
The present invention relates to a transmission power control method in a mobile communication system to which the ess) scheme is applied.

[0002]

2. Description of the Related Art In a CDMA system, a plurality of mobile terminals communicate with a base station by sharing the same frequency band. Therefore,
For example, when the mobile terminal A communicates with the base station, a signal transmitted from the mobile terminal A to the base station (desired signal) is a signal transmitted from another mobile terminal B to the base station (undesired signal). Causes interference, which hinders communication between the mobile terminal A and the base station. Similarly, the signal transmitted from mobile terminal A interferes with the communication between mobile terminal B and the base station.

[0003] The interference level increases in proportion to the reception level of the undesired signal wave received by the base station. The reception level of the undesired signal is proportional to the transmission power when the undesired signal is transmitted from the mobile terminal. Therefore, in order to minimize the interference level, it is necessary for the base station to control the transmission power from the mobile terminal so that the reception level at the base station is always minimized. When this control is ideally performed, the number of communicable channels becomes the maximum, and the number of communicable channels decreases as the state deviates from that state.

[0004] Regarding the transmission power control technology of CDMA mobile communication, for example, “IMT-2000 Study Committ” issued by the Radio Industry Association.
ee, Air-interface WG, SWG Document Title: Volume3
Specifications of Air-Interface for 3G Mobile Syst
em, Source: SWG, Version: 0-4.0, Date: December 18,
1997 "(hereinafter referred to as a W-CDMA system). A transmission power control method of the W-CDMA system will be described below. The direction in which a signal is transmitted to the mobile station and the downlink direction indicate the direction in which a signal is transmitted from the base station to the mobile terminal.

[0005] A base station measures a signal-to-interference power ratio (SIR) of an uplink signal transmitted from a mobile terminal, and transmits a transmission power control signal according to the measured SIR.
FIG. 29 shows a configuration diagram of a conventional base station. Antenna 210
After passing through the circulator 211, the reception signal received by the wireless communication module 212 is subjected to demodulation of a baseband signal and reception processing at a high / intermediate frequency.
A plurality of mobile terminals (MSa to MSn) are included in the received signal.
Are multiplexed, the base station performs synchronization acquisition / despreading circuit 213 with parameters set for each mobile terminal.
In steps a to 213n, synchronization acquisition and despreading of the received signal are performed. The signals output from the synchronization acquisition / despreading circuits 213a to 213n are input to detectors 214a to 214n, respectively, and are subjected to detection processing such as compensation for phase rotation. The signals output from the detection units 214a to 214n are input to decoding units 215a to 215n, respectively, and subjected to error control processing such as deinterleaving and Viterbi decoding, and then used as reception data.

On the other hand, synchronization acquisition / despreading circuits 213a to 213a-2
13n are output from the signal line 220a, respectively.
２２０220n and input to the upstream channel SIR measurement section 221. The uplink channel SIR measuring section 221 detects the SI of the received signal input through the signal lines 220a to 220n.
R (referred to as SIRa to SIRn), and S
IRa to SIRn are input to uplink channel transmission power control signal creation section 222 via signal lines 230a to 230n.

[0007] Uplink channel transmission power control signal creation section 22
2 are SIRa to SIRn and target SIRs (T-SIRa to T-SIRn) given to MSa to MSn in advance.
) And creates transmission power control signals (TPCa to TPCn) for MSa to MSn. FIG. 30 shows the configuration of the uplink channel transmission power control signal creation unit 222.
Shown in The uplink channel transmission power control signal generator 222 includes transmission power control signal generators 222a to 222n that receive SIRi and T-SIRi as inputs and output TPCi. Here, the subscript i represents any of a to n. FIG. 31 shows a configuration diagram of the transmission power control signal creation section 222i. The comparator 223i compares SIRi input via the signal line 230i with T-SIRi,
When i ≧ T-SIRi, a signal for selecting 0 is generated by the selector 224i, and when SIRi <T-SIRi, a signal for selecting 1 is generated by the selector 224i. Selector 22
4i selects either 0 or 1 according to the output of the comparator 223i and outputs it as TPCi via the signal line 231i. Here, TPCi = 0 is a signal for instructing the mobile terminal to reduce transmission power, and TPCi = 1 is a signal for instructing the mobile terminal to increase transmission power.

[0008] Frame components 225a-225 of FIG.
n are MSa to M that have been subjected to error control processing such as convolutional coding and interleaving in coding sections 222a to 222n.
The transmission data addressed to Sn and the transmission power control signal TPCa input from the uplink channel transmission power control signal creation unit 222
To TPCn constitute a frame according to a format defined by the system. Spreading circuits 223a to 223n perform spread spectrum processing of the output of the frame creation unit using parameters corresponding to MSa to MSn. The addition circuit 226 has M
To multiplex and transmit signals for Sa to MSn,
The transmission signals are added. The transmission signal output from the addition circuit 226 is transmitted from the antenna 210 after passing through the transmission wireless module 224 and the circulator 211.

The mobile terminal MSi receives the transmission power control signal T
PCi is received, and the transmission power is changed according to the demodulation result. FIG. 32 shows a configuration of a conventional mobile terminal. Antenna 1
After the reception signal received at 0 passes through the circulator 11, the reception radio module 12 performs demodulation of the baseband signal and reception processing at a high / intermediate frequency.
Since signals of a plurality of channels are multiplexed in the received signal, the mobile terminal uses the synchronization acquisition / despreading circuit 13 in which parameters are set for the channel used by the own terminal, to acquire synchronization of the received signal and to perform spectrum inverse. Perform diffusion processing. The signal output from the synchronization acquisition / despreading circuit 13 is subjected to detection processing such as phase rotation compensation in a detection section 14 and error control processing such as deinterleaving and Viterbi decoding in a decoding section 15. Is used as received data.

The received transmission power control signal is output from the detection unit 14 and then input to the transmission power control signal determination unit 40 through the signal line 16. Transmission power control signal determination unit 40
Indicates that the received transmission power control signal is “0” or “1”
Is determined. Transmission power control signal determination unit 40
Creates a control signal that selects, for example, “−1 dB” as the output of the selector 41 when the determination result of the transmission power control signal is “0”, and outputs the output signal of the selector 41 when the determination result is “1”. For example, a control signal for selecting “+1 dB” is generated and sent to the selector 41.

The selector 41 includes a transmission power control signal determination unit 4
According to the control signal input from 0, for example, either "+1 dB" or "-1 dB" is output as the change amount of the transmission power.

The transmission power calculator 19 determines the changed transmission power from the amount of change in the transmission power input from the selector 41 and the current transmission power input from the transmission power holding circuit 20. That is, when “+1 dB” is input from the selector, it is assumed that the changed transmission power is increased by 1 dB from the current transmission power, and conversely, “−1” is input from the selector.
If "dB" is input, it is assumed that the changed transmission power is reduced by 1 dB from the current transmission power.

The transmission signal is subjected to error control processing such as convolutional coding and interleaving in a coding unit 22, forms a frame of a format determined by the system in a frame forming unit 25, Diffusion processing is performed. The variable gain amplifier 21 amplifies the transmission signal with an appropriate gain so that the signal is transmitted at the transmission power specified by the transmission power calculation unit 19. The transmission signal output from the variable gain amplifier 21 is transmitted from the antenna 10 after passing through the transmission wireless module 24 and the circulator 11.

An example of how the transmission power of the mobile terminal changes when the mobile terminal performs the above operation is shown by a solid line 6 in FIG.
It is shown in FIG. The horizontal axis 60 represents time, and the vertical axis 61 represents transmission power of the mobile terminal. The horizontal axis 60 also includes the judgment results 83a to 83e of the transmission power control signals received from the time 120 to 124. As shown in FIG. 33, the mobile terminal increases the transmission power by 1 dB at times 122 and 124 when the control signal determination result is “1”, and transmits at times 120, 121 and 123 when the control signal determination result is “0”. Operate to reduce power by 1 dB.

[0015]

Problems to be Solved by the Invention There are the following two problems to be solved by the invention.

As the first problem, when the reception quality of the transmission power control signal is poor in the mobile terminal, the possibility that the received transmission power control signal becomes a demodulation result including an error increases. In this case, the demodulation result is set to “0” as in the related art.
Alternatively, in the method of determining as “1”, the possibility of erroneously determining a value different from the correct transmission power control signal value increases.

If the transmission power control signal to be determined as "1" is erroneously determined to be "0", that is, if the mobile terminal erroneously reduces the transmission power when the transmission power should be increased, the base station performs The quality of the signal received from the mobile terminal is degraded. As a result, the communication quality deteriorates and the communication is disconnected.

Conversely, if the transmission power control signal to be determined to be "0" is erroneously determined to be "1", that is, if the mobile terminal erroneously increases the transmission power when the mobile terminal should reduce the transmission power, the base station performs The amount of interference with other mobile terminals due to the signal of the mobile terminal increases. Accordingly, the communication quality of the other mobile terminals deteriorates and the communication is disconnected. This means that the number of mobile terminals that can communicate simultaneously decreases, and as a result, the communication capacity of the entire system decreases.

Further, when the determination result of the transmission power control signal having poor reception quality is biased to either “0” or “1” due to a DC offset component or the like included in the receiver of the mobile terminal, the communication is performed. A decrease in quality and a decrease in the communication capacity of the system will appear more remarkably.

As a second problem, when disconnecting communication,
When the receiving operation is stopped earlier than the transmitting operation as a control sequence in the base station,
When the operation of the despreading circuit 213i (i = 1, 2,..., N) stops earlier than the operation of the uplink channel SIR measuring unit 221, the uplink channel SIR measuring unit 221 stops the synchronization acquisition / despreading circuit. 213i output to SIRi
Therefore, it is considered that the operation becomes unstable. In this case, an inappropriate transmission power control signal TPCi is created and transmitted from the base station to the mobile terminal MSi. The mobile terminal MSi receives the inappropriate transmission power control signal TPC
As a result of controlling the transmission power according to i, there is a possibility that transmission will be performed with excessive transmission power. In this case, the base station increases the amount of interference with the other mobile terminals due to the signal of the mobile terminal MSi. Accordingly, the communication quality of the other mobile terminals deteriorates and the communication is disconnected. This reduces the communication capacity of the entire system as in the first problem.

[0021]

In order to solve the first problem, according to the present invention, a radio base station transmits a transmission power control signal for controlling transmission power of a mobile terminal, and the mobile terminal receives the transmission power control signal. From the configuration that calculates the likelihood of the transmission power control signal based on the signal and the reception quality, calculates the amount of change in transmission power based on the likelihood, and controls the transmission power of the mobile terminal based on the amount of change. Become.

[0022] In order to solve the first problem, the present invention is characterized in that the calculation of the likelihood is performed by also adding perch reception quality of a signal transmitted from the radio base station. The perch reception quality of the signal transmitted from the radio base station is compared with the reception quality of the transmission power control signal, and when only the reception quality of the receiving channel is deteriorated, the call of the receiving channel is disconnected. If both are deteriorated at the same time, it is determined that the terminal is no longer in an appropriate reception state due to circumstances such as the object being in the shade, and the likelihood is calculated based on these determination results.

In order to solve the first problem, the present invention updates and holds the upper and lower limits of the transmission power of the mobile terminal when the absolute value of the likelihood of the transmission power control signal is large. The transmission power of the mobile terminal is limited between the upper limit and the lower limit.

Further, in order to solve the first problem, the present invention calculates an average value of transmission power of a mobile terminal, and calculates the calculated average transmission power of the mobile terminal based on the magnitude of the likelihood, or The transmission power of the mobile terminal is switched so that the transmission power of the mobile terminal is calculated based on the likelihood.

Further, in order to solve the first problem, the present invention calculates an open-loop transmission power based on reception quality or reception power of another channel different from the channel in use, and calculates the magnitude of the likelihood. , The transmission power of the mobile terminal is switched so as to be the calculated open-loop transmission power or the transmission power of the mobile terminal calculated based on the likelihood.

[0026] In order to solve the first problem, the present invention provides a transmission power control signal comprising a binary signal;
The calculation of the likelihood is characterized by increasing the absolute value of the likelihood when the reception quality is good, and decreasing the absolute value of the likelihood when the reception quality is bad.

[0027] In order to solve the first problem, the present invention increases transmission power when the likelihood is equal to or more than a first reference value, and increases the transmission power when the likelihood is smaller than the first reference value and the second likelihood is smaller than the first reference value. The transmission power is maintained when the value is equal to or more than the reference value, and the transmission power is reduced when the value is smaller than the second reference value.

[0028] In order to solve the first problem, the present invention increases the transmission power when the likelihood is equal to or more than a first reference value, and when the likelihood is smaller than the first reference value and the second likelihood is smaller than the first reference value. When the transmission power is equal to or more than the reference value, the transmission power is toggled, and the second
When the value is smaller than the reference value, the transmission power is reduced.

Further, in order to solve the first problem, according to the present invention, the transmission power is increased when the likelihood is equal to or more than a first reference value, and the likelihood is smaller than the first reference value and the second likelihood is increased. When the value is equal to or more than the reference value, the change amount of the transmission power is set to the power corresponding to the likelihood, and when the value is smaller than the second reference value, the transmission power is reduced.

Further, in order to solve the second problem, according to the present invention, the radio base station measures the SIR of each mobile terminal,
The measured SIR is compared with a predetermined target SIR. If the SIR is equal to or larger than the target SIR, or if the radio base station is not receiving data from the mobile terminal, the transmission power is reduced. A transmission power control signal is generated, and if the SIR is less than the target SIR, a transmission power control signal for increasing transmission power is generated, and the generated transmission power control signal is transmitted to a mobile terminal.

[0031]

FIG. 1 shows a configuration diagram of a mobile terminal according to a first embodiment. Elements corresponding to those of the conventional mobile terminal shown in FIG. 32 are denoted by the same reference numerals.

The received signals processed by the antenna 10, the circulator 11, the receiving radio module 12, the synchronization acquisition / despreading circuit 13, and the detector 14 are transmitted via a signal line 16 to calculate a transmission power control signal likelihood. Input to the unit 30.

The transmission power control signal likelihood calculating section 30 calculates the likelihood of the transmission power control signal from the reception quality of the received transmission power control signal and the determination result of “0” or “1”. FIG. 2 shows the configuration of transmission power control signal likelihood calculating section 30. The transmission power control signal 0/1 determination unit 40 determines whether the received transmission power control signal is “0” or “1”.

[0034] Reception quality calculation section 50 calculates the reception quality of the received transmission power control signal and outputs it to likelihood calculation section 51. The reception quality calculated by the reception quality calculation unit 50 includes:
Basically, the received power, SIR, etc., measured instantaneously when receiving the transmission power control signal should be used. On the other hand, a long-time integration operation is required to accurately observe the received power and SIR. When the above-described long-time integrated reception power or SIR (hereinafter, referred to as a long-time integration value) is used for transmission power control that requires high speed, control delay becomes large and transmission power cannot be appropriately controlled. Can be considered. Therefore, the reception quality calculation unit 50 calculates the transmission power control signal, the reception power of the signal received at a time that is temporally close to the transmission power control signal, and the integration result of the SIR (hereinafter, referred to as a short-time integration value). The reception quality of the transmission power control signal is calculated.

Further, since the short-time integrated value is considered to have a large error, if the short-time integrated value is directly used for calculating the reception quality, there is a possibility that an erroneous reception quality may be calculated. Therefore, for example, the reception power calculation unit 50 may compare the long-term integration value and the short-time integration value, and may perform an operation of outputting poor reception quality if the difference between the two is large.

Further, when the receiving channel is a call disconnection,
Alternatively, the reception quality calculation unit 50 may perform the following operation in order to estimate that the reception state is no longer appropriate due to circumstances such as being behind a shadow. The mobile terminal is, for example, a W-CDM.
It measures the reception power or SIR (hereinafter, perch reception quality) of a channel that is always transmitted from the base station and whose transmission power is known, such as a perch channel in the A system, and is known. FIG. 34 shows the configuration of the reception quality calculation unit in this case. The perch reception quality measuring section 300 measures the perch reception quality. The comparison unit 301 compares the short-time integration value with the perch reception quality obtained from the perch reception quality measurement unit 300. The reception quality determination unit 302 determines from the comparison result of the comparison unit 301 that only the reception quality of the receiving channel is degraded, that the receiving channel is disconnected, or that both are degraded simultaneously. Determines that the terminal is no longer in an appropriate reception state due to circumstances such as the object being behind a shadow, and outputs poor reception quality.

The likelihood calculating section 51 outputs a transmission power control signal 0/1.
The likelihood of the transmission power control signal is calculated based on the determination result of the determination unit 40 and the calculation result of the reception quality calculation unit 50.
FIG. 3 shows an example of the relationship between the determination result of the transmission power control signal 0/1 determination unit 40, the calculation result of the reception quality calculation unit 50, and the likelihood.
Is indicated by a broken line 150. Hereinafter, the result of likelihood calculation in the case of FIG. 3 will be described. When the determination result of the transmission power control signal is 1, the likelihood assumes a positive value. Conversely, when the determination result is 0, the likelihood assumes a negative value. Further, when the reception quality is good, the absolute value of the likelihood is increased, and when the reception quality is bad, the absolute value of the likelihood is reduced.

The likelihood of the transmission power control signal calculated by the above method is input to the transmission power variation calculator 31 in FIG.
The transmission power variation calculator 31 calculates the variation of the transmission power based on the likelihood of the input transmission power control signal. FIG. 4 shows the configuration of the transmission power change amount calculation unit 31 according to the first embodiment. Likelihood determining section 70 includes transmission power control signal likelihood calculating section 30.
For example, “+1 dB (increase)”, “−1” as the amount of change in transmission power based on the likelihood of the transmission power control signal input from
A control signal for selecting one of “dB (decrease)” and “0 dB (no change)” is generated and output to the selector 71.
FIG. 5 shows an example of the operation of the likelihood determination unit 70 in the first embodiment.
Shown in When the likelihood of the input transmission power control signal is in the region 100 of α + or more, the likelihood determination unit 70 outputs a control signal to the selector 71 such that “+1 dB” is selected by the selector 71. Similarly, when the likelihood of the input transmission power control signal is in the region 101 that is equal to or more than α− and less than α +, the likelihood determination unit 70 transmits a control signal for which “0 dB” is selected to the input transmission signal. When the likelihood of the power control signal exists in the region 102 less than α−, the likelihood determining unit 70 outputs a control signal to select “−1 dB” to the selector 71. The selector 71 selects a transmission power change amount according to the control signal from the likelihood determination unit 70, and outputs it to the transmission power calculation unit 19 in FIG.

The transmission power calculating section 19 shown in FIG. 1 uses the conventional transmission power inputted from the transmission power holding circuit 20 and the transmission power change amount inputted from the transmission power variation calculating section 31 to obtain the conventional transmission power. The transmission power is calculated similarly to the mobile terminal. The transmission signal processed by the encoding unit 21 and the spreading circuit 23 is amplified by the variable gain amplifier 21 so as to be transmitted at the transmission power, and then transmitted through the transmission wireless module 24 and the circulator 11 to the antenna 10. Sent by

An example of how the transmission power of the mobile terminal changes when the mobile terminal performs the operation of the first embodiment is shown by a solid line 63 in FIG. As shown in FIG. 6, during the time 103 when the likelihood of the transmission power control signal is equal to or more than α− and less than α +, the mobile terminal operates so that the amount of change in transmission power is 0 dB, that is, the transmission power is not changed.

Next, the operation of the mobile terminal according to the second embodiment will be described. The configuration of the mobile terminal of the second embodiment is as shown in FIG. 1 as in the first embodiment. In the second embodiment, the configuration of the transmission power change amount calculation unit 31 is different from that of the first embodiment. FIG. 7 shows the configuration of the transmission power change amount calculation unit 31 according to the second embodiment. The same elements as those of the first embodiment are denoted by the same reference numerals.

Based on the likelihood of the transmission power control signal input from transmission power control signal likelihood calculating section 30, likelihood determining section 70 determines, for example, “+1 dB (increase)” and “−1 dB” as the amount of change in transmission power. (Decrease) ”, and a control signal for selecting which of the“ toggle unit 72 (toggle operation) ”is selected, and outputs the control signal to the selector 71. The operation of the toggle unit 72 is shown in FIG. When the input is “+1 dB”, the toggle unit 72 sets “−1”.
dB) and outputs “+ 1d” when the input is “−1 dB”.
B "is output. FIG. 9 shows an example of the operation of the likelihood determination unit 70 in the second embodiment. If the likelihood of the input transmission power control signal is in the region 100 of α + or more, the likelihood determination unit 70 determines “+ 1d
A control signal for selecting “B” is output to the selector 71. Similarly, the likelihood of the input transmission power control signal is α
In the case where the likelihood determining unit 70 determines that the likelihood determining unit 70 selects the “toggle unit 72”, the likelihood determining unit 70 converts the control signal into a region 102 in which the likelihood of the input transmission power control signal is less than α−. , The likelihood determination unit 70 determines “−1d
A control signal for selecting “B” is output to the selector 71. The selector 71 selects a transmission power change amount according to the control signal from the likelihood determination unit 70, and outputs it to the transmission power calculation unit 19 in FIG. Hereinafter, the operation until the transmission signal is transmitted from the antenna 10 is the same as that of the first embodiment.

FIG. 10 shows an example of how the transmission power of the mobile terminal changes when the mobile terminal performs the operation of the second embodiment.
The solid line 64 of FIG. As shown in FIG. 10, during the time 103 during which the likelihood of the transmission power control signal is equal to or more than α− and less than α +, the mobile terminal determines that the transmission power change amounts are “+1 dB” and “−1d”.
B ”is alternately repeated.

Next, the operation of the mobile terminal according to the third embodiment will be described. The configuration of the mobile terminal according to the third embodiment is as shown in FIG. 1 as in the first embodiment and the second embodiment.
In the third embodiment, the configuration of the transmission power change amount calculation unit 31 is different from the first embodiment and the second embodiment. FIG. 11 shows the configuration of the transmission power change amount calculation unit 31 according to the third embodiment. The likelihood-transmission power change amount conversion unit 73 converts the likelihood of the transmission power control signal input from the transmission power control signal likelihood calculation unit 30 into a transmission power change amount. An example of the operation of the likelihood-transmission power change amount conversion unit 73 is shown by a broken line 74 in FIG. In FIG. 12, when the likelihood of the input transmission power control signal is equal to or more than α +, likelihood-transmission power change amount conversion section 73 outputs, for example, “+1 dB” to transmission power calculation section 19 as the transmission power change amount. Similarly, when the likelihood of the input transmission power control signal is less than α−, the likelihood-transmission power variation converter 73 outputs, for example, “−1 dB” as the transmission power variation to the transmission power calculator 19. Here, when the likelihood of the input transmission power control signal is equal to or more than α− and less than α +, the likelihood-transmission power change amount conversion unit 73 responds to the likelihood of the transmission power control signal by, for example, the broken line in FIG. The transmission power change amount that changes like 74 is output to the transmission power calculation unit 19. Hereinafter, the operation until the transmission signal is transmitted from the antenna 10 is the same as that of the first embodiment.

FIG. 13 shows an example of how the transmission power of the mobile terminal changes when the mobile terminal performs the operation of the third embodiment.
The solid line 65 of FIG. As shown in FIG. 13, during the time 103 during which the likelihood of the transmission power control signal is equal to or more than α− and less than α +, the mobile terminal changes the transmission power to a value smaller than “+1 dB” or “−1 dB”. The mobile terminal controls the transmission power.

FIG. 14 shows the configuration of the mobile terminal according to the fourth embodiment.
Shown in Components corresponding to the configuration of the mobile terminal shown in FIG. 32 and FIG. 1 are denoted by the same reference numerals. As in the first embodiment, the likelihood of the transmission power control signal calculated by the transmission power control signal likelihood calculation unit 30 is calculated by the transmission power change amount calculation unit 3.
1 is input.

Transmission power variation calculating section 3 of the fourth embodiment
1 is shown in FIG. Based on the likelihood of the transmission power control signal input from transmission power control signal likelihood calculating section 30, likelihood determining section 130 calculates, for example, “+1” as the amount of change in transmission power.
A control signal for selecting either “dB (increase)” or “−1 dB (decrease)” is generated and output to the selector 131. FIG. 16 illustrates an example of the operation of the likelihood determination unit 130 according to the fourth embodiment. If the likelihood of the input transmission power control signal is in an area of 0 or more, likelihood determination section 130 outputs a control signal to selector 131 to select “+1 dB”. Conversely, when the likelihood of the input transmission power control signal is in a region where it is less than 0,
Likelihood determining section 130 outputs a control signal to selector 131 such that “−1 dB” is selected. The selector 131 selects the transmission power change amount according to the control signal from the likelihood determination unit 130, and outputs it to the transmission power calculation unit 19 in FIG.
The transmission power calculator 19 calculates the transmission power of the mobile terminal as in the first embodiment.

The transmission power limiting section 32 includes a transmission power calculating section 19
Is compared with the transmission power limit value calculated inside the transmission power limiting unit 32 to limit the transmission power of the mobile terminal. FIG. 17 shows the configuration of transmission power limiting section 32. The transmission power input from transmission power calculation section 19 is input to transmission power limit value calculation section 90 and comparison section 91. FIG. 18 shows an example of the operation of the transmission power limit value calculation section 90. The transmission power limit value calculation unit 90 first compares the likelihood of the transmission power control signal input from the transmission power control signal likelihood calculation unit 30 with the thresholds β− and β +. Here, when the likelihood of the transmission power control signal does not satisfy the relationship of β− ≦ (likelihood) <β +, that is, when the absolute value of the likelihood of the transmission power control signal is large, the upper limit value TXPU of the transmission power and the transmission power Is updated. By this operation, when the absolute value of the likelihood of the transmission power control signal is large, that is, when the reception quality of the transmission power control signal is good, the upper limit value and the lower limit value of the transmission power of the mobile terminal are calculated. When the absolute value of the likelihood of the control signal is small, that is, when the reception quality of the transmission power control signal is poor, the upper limit and the lower limit of the transmission power of the mobile terminal are held.

The comparing section 91 in FIG.
And the transmission power limit value calculation unit 90
Is compared with the upper limit value and the lower limit value of the transmission power input from. Here, when the transmission power input from transmission power calculation section 19 is larger than upper limit value TXPU of the transmission power input from transmission power limit value calculation section 90, comparison section 91 changes the transmission power to TXPU and changes to FIG. Transmission power holding circuit 2
0 and output to the variable gain amplifier 21. Conversely, when the transmission power input from the transmission power calculation unit 19 is smaller than the lower limit value TXPL of the transmission power input from the transmission power limit value calculation unit 90, the comparison unit 91 changes the transmission power to TXPL and returns to FIG. Transmission power holding circuit 20 and variable gain amplifier 2
Output to 1. Further, when the transmission power input from the transmission power calculation unit 19 exists between TXPU and TXPL, the transmission power input from the transmission power calculation unit 19 is used as it is in the transmission power holding circuit 20 and the variable gain amplifier in FIG. 21. Hereinafter, the operation until the transmission signal is transmitted from the antenna 10 is the same as that of the first embodiment.

FIG. 19 shows an example of how the transmission power of the mobile terminal changes when the mobile terminal performs the operation of the fourth embodiment.
The solid line 66 of FIG. As shown in FIG. 19, during the time 103 during which the likelihood of the transmission power control signal is equal to or more than α− and less than α +, the upper limit value TXPU and the lower limit value TXPL of the transmission power of the mobile terminal are kept constant. In the example of FIG.
, The transmission power of the mobile terminal is equal to the lower limit TXPL of the transmission power.
It is limited so that it does not fall below.

In the fourth embodiment, the transmission power variation calculator 31 may have the configuration shown in the first to third embodiments.

FIG. 20 shows the configuration of the mobile terminal according to the fifth embodiment.
Shown in Components corresponding to the configuration of the mobile terminal shown in FIG. 32 and FIG. 1 are denoted by the same reference numerals. As in the first embodiment, the likelihood of the transmission power control signal calculated by the transmission power control signal likelihood calculation unit 30 is calculated by the transmission power change amount calculation unit 3.
1 is input. The transmission power variation calculator 31 is the transmission power variation calculator 3 described in the first to fourth embodiments.
Any one of the configurations and operations may be used. The change amount of the transmission power calculated by the transmission power change amount calculation unit 31 is input to the transmission power calculation unit 19.

The transmission power calculator 19 calculates the transmission power of the mobile terminal as in the first embodiment.

The transmission power calculated by transmission power calculation section 19 is input to transmission power selection section 33. The transmission power selection unit 33 selects transmission power according to the likelihood of the transmission power control signal input from the transmission power control signal likelihood calculation unit 30.

Transmission power selecting section 3 in fifth embodiment
3 is shown in FIG. Based on the likelihood of the transmission power control signal input from transmission power control signal likelihood calculation section 30, likelihood determination section 140 transmits transmission power input from transmission power calculation section 19 as transmission power or transmission power averaging. Part 14
A control signal for selecting any one of the transmission powers input from 2 is generated and output to the selector 141. FIG. 22 shows an example of the operation of the likelihood determination unit 140 in the fifth embodiment. Area 10 in which the likelihood of the input transmission power control signal is γ + or more
4 or less than γ−, that is, when the reception quality of the received transmission power control signal is good,
Likelihood determination section 140 outputs a control signal to selector 141 such that selector 141 selects the transmission power input from transmission power calculation section 19. Conversely, the region 10 in which the likelihood of the input transmission power control signal is not less than γ− and less than
5, that is, if the received transmission power control signal has poor reception quality, the likelihood determining section 140 sends a control signal to the selector 141 such that the transmission power input from the transmission power averaging section 142 is selected. Output. Selector 14
1 selects the transmission power according to the control signal from the likelihood determination section 140 and outputs the transmission power to the transmission power holding circuit 20 and the variable gain amplifier 21 in FIG. Here, the transmission power averaging unit 142 calculates an average value of the input transmission power,
It is to be output to the selector 142.

The operation until the transmission signal is transmitted from the antenna 10 is the same as in the first embodiment.

Next, the operation of the mobile terminal according to the sixth embodiment will be described. The configuration of the mobile terminal according to the sixth embodiment is as shown in FIG. 20 as in the fifth embodiment. In the sixth embodiment, the configuration of the transmission power selection unit 33 is different from that of the fifth embodiment. FIG. 2 shows the configuration of the transmission power selection unit 33 according to the sixth embodiment.
3 is shown. Based on the likelihood of the transmission power control signal input from transmission power control signal likelihood calculation section 30, likelihood determination section 150 transmits transmission power input from transmission power calculation section 19 as transmission power or open-loop transmission power. A control signal for selecting one of the transmission powers input from calculation section 152 is created and output to selector 151. FIG. 24 shows an example of the operation of the likelihood determining section 150 in the sixth embodiment. If the likelihood of the input transmission power control signal is in region 107 equal to or more than δ + or in region 109 less than δ−, that is, when the reception quality of the received transmission power control signal is good, likelihood determination section 150 selects selector 151. Transmission power calculation unit 1
A control signal for selecting the transmission power input from the selector 9 is output to the selector 151. Conversely, if the likelihood of the input transmission power control signal is in the region 108 of δ− or more and less than δ +, that is, if the reception quality of the received transmission power control signal is poor, likelihood determination section 150 performs open-loop transmission. A control signal for selecting the transmission power input from power calculation section 152 is output to selector 151. Selector 15
1 selects the transmission power in accordance with the control signal from the likelihood determination section 150 and outputs the transmission power to the transmission power holding circuit 20 and the variable gain amplifier 21 in FIG.

The open-loop transmission power calculation section 152 uses a channel different from the channel used for communication, for example, W-CDM
By using the reception quality and reception power of the perch channel and the like in the A scheme, the amount of attenuation between the mobile terminal and the base station is estimated, and the transmission power of the mobile terminal that satisfies the required reception quality at the base station is estimated. calculate. The open-loop transmission power calculator 152 calculates the calculated transmission power by the selector 15.
Output to 2.

The operation until the transmission signal is transmitted from the antenna 10 is the same as in the first embodiment.

FIG. 25 shows the configuration of the base station according to the seventh embodiment. Components corresponding to the configuration of the conventional base station shown in FIG. 29 are denoted by the same reference numerals. The received signal is transmitted to the uplink channel SIR measurement unit 2 in the same manner as the conventional base station.
SIR for each mobile terminal (MSa to MSn) at 21
(SIRa to SIRn) are measured, and the signal lines 230a to 230
The signal is input to the uplink channel transmission power control signal creation section 250 via 230n. Uplink channel transmission power control signal creation section 250 includes SIRa to SIRn and MSa to MSn
The target SIR (T-SIRa to T-T
-SIRn) and MSa to MSn
Based on control signals RXa to RXn indicating whether or not a reception operation is being performed on a signal transmitted from MSa to RXa.
Transmission power control signals (TPCa to TPCn) for MSn
To be created).

Uplink channel transmission power control signal creation section 25
0 is shown in FIG. The uplink channel transmission power control signal creation section 250 includes transmission power control signal creation sections 250a to 250n that receive SIRi, T-SIRi, and RXi as inputs and output TPCi. Where the subscript i
Represents one of a to n. FIG. 27 shows a configuration diagram of transmission power control signal creation section 250i. Comparator 25
4i are SIRi and T input through a signal line 230i.
-SIRi is compared, and when SIRi ≧ T-SIRi, 0 is selected by the selector 251i (signal instructing reduction of transmission power).
In the case of SIRi <T-SIRi, the selector 251i creates a signal for selecting 1 (a signal instructing an increase in transmission power). The selector 251i is the comparator 2
Select either 0 or 1 according to the output of 54i,
The signal is output to the selector 253i via the signal line 252i.
The selector 253i determines the transmission power control signal TPCi according to the signal RXi for controlling whether or not the reception operation is being performed. FIG. 28 shows the operation of the selector 253i. RX
If i is a signal indicating that the receiving operation is being performed, the selector 253i outputs the transmission power control signal TPCi to the signal line 25i.
Select the signal input via 2i. Conversely, if the signal indicates that RXi is stopping reception, the selector 25
3i selects 0 (signal instructing a decrease in transmission power) as the transmission power control signal TPCi.

MSa to MS prepared by the above method
The transmission power control signals TPCa to TPCn for n are transmitted through signal lines 231a to 231n.
To 225n, subjected to the same processing as the conventional base station, and then transmitted from the antenna 210.

[0063]

According to the present invention, it is possible for a mobile terminal to reduce the influence of erroneous control of transmission power control by a transmission power control signal including a reception error. Further, by controlling the base station not to transmit an inappropriate transmission power control signal after the reception operation is stopped, it is possible to prevent the mobile terminal from transmitting with excessive transmission power. Therefore, it is possible to avoid a deterioration in communication quality and a decrease in the capacity of the entire system due to erroneous control.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a mobile terminal of the present invention.

FIG. 2 is a configuration diagram of a transmission power control signal likelihood calculation unit of the present invention.

FIG. 3 is a diagram illustrating a likelihood calculation method according to the present invention.

FIG. 4 is a configuration diagram of a transmission power change amount calculation unit of the present invention.

FIG. 5 is a diagram illustrating an example of an operation of a likelihood determination unit according to the present invention.

FIG. 6 is a diagram illustrating an example of a change in transmission power of a mobile terminal according to the present invention.

FIG. 7 is a configuration diagram of a transmission power change amount calculation unit according to the present invention.

FIG. 8 is an explanatory diagram of the operation of the toggle unit of the present invention.

FIG. 9 is an explanatory diagram of the operation of the likelihood determination unit of the present invention.

FIG. 10 is a diagram illustrating an example of a change in transmission power of a mobile terminal according to the present invention.

FIG. 11 is a configuration diagram of a transmission power change amount calculation unit according to the present invention.

FIG. 12 is an explanatory diagram of an operation of a transmission power change amount calculating section of the present invention.

FIG. 13 is a diagram illustrating an example of a change in transmission power of a mobile terminal according to the present invention.

FIG. 14 is a configuration diagram of a mobile terminal of the present invention.

FIG. 15 is a configuration diagram of a transmission power change amount calculation unit of the present invention.

FIG. 16 is an explanatory diagram of the operation of the likelihood determination section of the present invention.

FIG. 17 is a configuration diagram of a transmission power control unit of the present invention.

FIG. 18 is a configuration diagram of a transmission power limit value calculation unit according to the present invention.

FIG. 19 is a diagram illustrating an example of a change in transmission power according to the present invention.

FIG. 20 is a configuration diagram of a mobile terminal of the present invention.

FIG. 21 is a configuration diagram of a transmission power selection unit of the present invention.

FIG. 22 is an explanatory diagram of the operation of the likelihood determination unit of the present invention.

FIG. 23 is a configuration diagram of a transmission power selection unit of the present invention.

FIG. 24 is a configuration diagram of a likelihood selection unit of the present invention.

FIG. 25 is a configuration diagram of a base station of the present invention.

FIG. 26 is a configuration diagram of an uplink channel transmission power control signal creation unit of the present invention.

FIG. 27 is a configuration diagram of a transmission power control signal creation unit of the present invention.

FIG. 28 is an explanatory diagram of the operation of the selector 235i of the present invention.

FIG. 29 is a configuration diagram of a conventional base station.

FIG. 30 is a configuration diagram of an uplink channel transmission power control signal creation unit of the present invention.

FIG. 31 is a configuration diagram of a conventional transmission power control signal creation unit.

FIG. 32 is a configuration diagram of a conventional mobile terminal.

FIG. 33 is a diagram showing a state of conventional transmission power change.

FIG. 34 is a configuration diagram of a reception quality calculation unit using perch reception quality.

[Explanation of symbols]

 Reference Signs List 10 antenna 11 circulator 12 reception high frequency unit 14 detection unit 15 decoding unit 19 transmission power calculation unit 20 transmission power holding circuit 22 encoding 23 spreading circuit 24 transmission high frequency unit 25 frame creation unit 30 transmission power control signal likelihood calculation unit 31 transmission power Change amount calculation unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Yano 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Takara Garaku 1-1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside the Central Research Laboratory of the Works (72) Inventor Toshiro Suzuki 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Information and Communication Business Department, Hitachi, Ltd. F-term (reference) in Diddy Corporation 5K022 EE01 EE21 5K060 BB07 CC04 CC12 DD04 HH06 HH13 JJ18 KK08 LL01 5K067 AA23 CC10 DD27 DD45 EE02 EE10 GG08 HH21

Claims (11)

[Claims] 1. A transmission power control method in a code division multiple access communication system comprising a radio base station and a mobile terminal, wherein the radio base station transmits a transmission power control signal for controlling transmission power of a mobile terminal, The terminal calculates a likelihood of the transmission power control signal based on the received transmission power control signal and the reception quality, calculates a change amount of the transmission power based on the likelihood, and calculates a likelihood of the mobile terminal based on the change amount. A transmission power control method in a code division multiple access communication system, comprising controlling transmission power. 2. The transmission power control method in a code division multiple access communication system according to claim 1, wherein the calculation of the likelihood is performed by adding perch reception quality of a signal transmitted from the radio base station. A transmission power control method in a code division multiple access communication system, comprising: 3. The transmission power control method in a code division multiple access communication system according to claim 1, wherein perch reception quality of a signal transmitted from the radio base station is compared with reception quality of a transmission power control signal. When only the reception quality of the receiving channel deteriorates, it is determined that the call of the receiving channel has been disconnected, and when both deteriorate at the same time, the terminal is not in an appropriate receiving state due to circumstances such as the terminal being in the shadow. A transmission power control method in a code division multiple access communication system, wherein the likelihood is calculated based on these determination results. 4. The transmission power control method for a code division multiple access communication system according to claim 1, wherein an upper limit value and a lower limit value of the transmission power of the mobile terminal when the absolute value of the likelihood of the transmission power control signal is large. The transmission power control method in the code division multiple access communication system, wherein the transmission power of the mobile terminal is limited between the upper limit and the lower limit. 5. The transmission power control method in a code division multiple access communication system according to claim 1, wherein an average value of transmission power of the mobile terminal is calculated, and the calculated mobile terminal is calculated based on the likelihood. The average transmit power of
A transmission power control method in a code division multiple access communication system, wherein the transmission power of the mobile terminal is switched so that the transmission power of the mobile terminal is calculated based on the likelihood. 6. A transmission power control method in a code division multiple access communication system according to claim 1, wherein an open-loop transmission power is calculated based on reception quality or reception power of another channel different from the channel being used. Based on the magnitude of the likelihood, the calculated open-loop transmission power, or, switching the transmission power of the mobile terminal, so that the transmission power of the mobile terminal calculated based on the likelihood, Transmission power control method in a code division multiple access communication system. 7. The transmission power control method in a code division multiple access communication system according to claim 3, wherein the transmission power control signal is a binary signal, and the likelihood calculation is performed when reception quality is good. Increases the absolute value of the likelihood,
A transmission power control method in a code division multiple access communication system, wherein the absolute value of likelihood is reduced when reception quality is poor. 8. The transmission power control method in a code division multiple access communication system according to claim 7, wherein the transmission power is increased when the likelihood is equal to or more than a first reference value, and the likelihood is set to the first reference value. A transmission power control method in a code division multiple access communication system, wherein the transmission power is maintained when the value is smaller than the second reference value and the transmission power is maintained when the value is smaller than the second reference value. 9. The transmission power control method in a code division multiple access communication system according to claim 7, wherein the transmission power is increased when the likelihood is equal to or more than a first reference value, and the likelihood is increased by the first reference value. A transmission power control method in a code division multiple access communication system, wherein the transmission power is toggled when it is smaller than a second reference value and lower than the second reference value. . 10. The transmission power control method in a code division multiple access communication system according to claim 7, wherein the transmission power is increased when the likelihood is equal to or more than a first reference value, and the likelihood is set to the first reference value. A code division multiple unit characterized in that when the value is smaller than the second reference value and is equal to or greater than a second reference value, the amount of change in transmission power is set to power corresponding to the likelihood, and when the value is smaller than the second reference value, the transmission power is reduced. A transmission power control method in a connection communication system. 11. A transmission power control method in a code division multiple access communication system comprising a radio base station and a mobile terminal, wherein the radio base station measures an SIR for each of the mobile terminals, and determines the measured SIR with each of the measured SIRs in advance. Given goal S
If the SIR is greater than or equal to the target SIR or if the radio base station is not receiving data from the mobile terminal, a transmission power control signal for reducing transmission power is generated. A transmission power control method for a code division multiple access communication system, characterized in that a transmission power control signal for increasing transmission power is generated when the value is less than the above, and the generated transmission power control signal is transmitted to a mobile terminal.