JP3426991B2 - Transmission power control circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a CDMA (Code
The present invention relates to a transmission power control circuit used in a mobile communication terminal device of the Division Multiple Access (SDM) system.

[0002]

2. Description of the Related Art In a CDMA mobile communication terminal device conforming to TIA / EIA / IS-95A, a transmission signal to a base station is generated as a quadrature modulation signal by a process shown in FIG. The transmission signal generated by this processing has a signal vector that does not pass through the origin as shown in FIG. 8 and the difference between the average power and the instantaneous maximum power is relatively small, so it is relatively affected by the saturation of the power amplifier and the like. A difficult OQPSK signal is used.

Further, the maximum transmission power is controlled so as not to exceed a level at which an out-of-band spurious component deteriorates beyond an allowable value due to saturation of amplification power of a power amplifier. FIG. 9 is a circuit block diagram of a conventional transmission power control circuit, and the transmission power control of a conventional CDMA mobile communication terminal apparatus will be described below with reference to this figure.

Transmission power control of a CDMA mobile communication terminal device is generally performed by using both open loop control and closed loop control. First, the open loop control will be described.

The variable reception gain amplifier 901 amplifies a reception signal according to a gain control signal s1 described later. Then, the reception signal amplified here is input to the modem reception unit 902 and the power detection circuit 903.

The modem receiving section 902 demodulates the received signal which has been code-spread. On the other hand, the power detection circuit 90
In 3, the DC signal (power detection signal) corresponding to the average power level of the received signal (hereinafter referred to as the received signal level)
Convert to. This power detection signal is subtracted from the reference DC signal Pref which is the control target by the subtraction circuit 904, and this difference is output to the integration circuit 905 as an error signal (gain control signal s1). This error signal is integrated by the integration circuit 905.
Are integrated into the gain control signal s2 of the reception gain variable amplifier 901 described above.

As described above, the variable reception gain amplifier 901,
Since the control loop including the power detection circuit 903, the subtraction circuit 904, and the integration circuit 905 operates so that the error signal approaches 0, even if the received signal level changes,
The gain of the variable reception gain amplifier 901 is controlled so that the power detection signal becomes substantially equal to the reference DC signal Pref.

Therefore, the relationship between the gain control signal s1 and the gain of the variable reception gain amplifier 901 is shown in FIG.
By doing so, the relationship between the received signal level and the gain control signal s1 becomes as shown in FIG. 10 (b).

The gain control signal s2 obtained by the integrating circuit 905 is supplied to the variable transmission gain amplifier 908 via the adding circuit 906 and the limiter circuit 907. In the variable transmission gain amplifier 908, the transmission signal modulated by code spreading in the modem transmission unit 911 is converted into the gain control signal s.
Amplify according to 2.

Here, if the relationship between the gain of the variable transmission gain amplifier 908 and its gain control signal is as shown in FIG. 11 (a), the relationship between the received signal level and the transmitted signal level is as shown in FIG. 11 (b). .

By controlling in this way, the mobile communication terminal device increases the transmission level when the reception signal level becomes smaller away from the base station, and conversely, when the reception signal level becomes closer to the base station and the reception signal level becomes larger, the transmission signal level becomes higher. It works to make it smaller. By such an operation, the level of the uplink signal reaching the base station is kept constant, and the interference between mobile communication terminal devices sharing the same frequency is made fair.

On the other hand, the closed loop control is performed to compensate for an error that occurs in the open loop control. Since this error is due to the non-correlation of fading caused by the difference between the frequencies of the uplink and the downlink, the S / N ratio of the uplink (transmission signal) of the mobile communication terminal device is received by the receiver of the base station. Is monitored so that the monitor result is within the expected range, 1.25 [mse
The power control signal is superimposed on the downlink every c] and transmitted to the mobile communication terminal device.

On the other hand, the mobile communication terminal device is shown in FIG.
The modem receiving section 902 extracts the power control signal and inputs it to the closed loop control circuit 909. The closed loop control circuit 909 sets the correction value of the gain control signal to the transmission gain variable amplifier 908 based on the information of the power control signal,
An adder 906 is added.

Next, the limiter circuit 907 for controlling the maximum transmission power will be described. When the above-mentioned open loop control and closed loop control are working to increase the transmission output of the mobile communication terminal device, the saturation level of the power amplifier (PA) 910 or higher, that is, the maximum transmission level of the mobile communication terminal device or higher. When the transmission level is increased, the transmission spectrum is widened, the out-of-band spurious component increases, and unnecessary interference is given to the communication using the near frequency. Therefore, such a situation is prevented by providing a limiter circuit 907 so that the gain control signal to the variable transmission gain amplifier 908 does not exceed a predetermined upper limit value.

By the way, recently, with the increasing demand for higher speed of mobile data communication, studies are being made to speed up the upstream transmission rate by multiplexing transmission signals with a plurality of codes as shown in FIG. .

In this case, the multiplexed transmission signal is no longer OQPSK, the signal vector passes near the origin, and the difference between the average power and the instantaneous maximum power increases as the number of multiplexing increases.

Therefore, in the above-described conventional transmission power control circuit, when the code transmission rate is increased by code-multiplexing, the difference between the average power and the instantaneous maximum power of the transmission signal becomes large. If it is attempted to control the maximum transmission level that is the same as that at the time of transmission, there is a problem that the out-of-band spurious component deteriorates beyond the allowable value.

[0018]

In the conventional transmission power control circuit, when code multiplexing is used to increase the uplink transmission rate, the difference between the average power and the instantaneous maximum power of the transmission signal becomes large, so that single code transmission is performed. If the maximum transmission level is controlled to be the same as that at the time, there is a problem that the out-of-band spurious component deteriorates beyond the allowable value.

The present invention has been made to solve the above problems, and provides a transmission power control circuit that does not cause deterioration of out-of-band spurious components even when code multiplexing is performed to increase the upstream transmission rate. With the goal.

Further, the present invention provides a transmission power control circuit which does not cause deterioration of out-of-band spurious components and shortening of communication distance with a base station even if code multiplexing is performed to increase the upstream transmission rate. The purpose is to do.

[0021]

In order to achieve the above object, the present invention provides a transmission power control for controlling the power intensity of a transmission signal capable of code-multiplexing by a direct spreading method according to the power intensity of a reception signal. In the circuit, multiplex number detection means for detecting the code multiplex number of the transmission signal, amplification means for amplifying the power of the transmission signal, gain control means for controlling the gain of this amplification means according to the power intensity of the reception signal, Maximum power intensity for controlling the amplifying means according to the number of code multiplexes detected by the multiplex number detecting means so that the maximum value of the power intensity of the transmission signal amplified by the amplifying means becomes a value according to the number of code multiplexes. A control means is provided.

In the transmission power control circuit having the above structure, the code multiplex detected by the multiplex number detecting means is set so that the maximum value of the power intensity of the transmission signal amplified by the amplifying means becomes a value corresponding to the code multiplex number. The amplification means is controlled according to the number. Therefore, according to the transmission power control circuit having the above-described configuration, the maximum value of the power intensity of the transmission signal amplified by the amplification means becomes a value according to the number of code multiplexes, and thus code multiplex is performed to increase the upstream transmission rate. Even if it does, the out-of-band spurious component is not deteriorated.

Further, according to the present invention, in the transmission power control circuit for controlling the power intensity of the transmission signal capable of code multiplexing by the direct spreading method according to the power intensity of the reception signal, the multiplexing for detecting the code multiplexing number of the transmission signal. Number detection means, amplification means for amplifying the power of the transmission signal, gain control means for controlling the gain of this amplification means according to the power intensity of the reception signal, and number of code multiplexes detected by the multiplex number detection means Then, the gain characteristic of the amplifying means is controlled, and the characteristic control means for varying the saturation level is provided.

In the transmission power control circuit configured as described above, the gain characteristic of the amplifying means is controlled in accordance with the number of code-multiplexed transmission signals, and the saturation level thereof is varied. Therefore, according to the transmission power control circuit having the above configuration, the gain characteristic of the amplifying means can be changed according to the number of code multiplexes of the transmission signal, so that the saturation of the amplification capability due to the increase of the number of multiplexes is prevented, and the code multiplexing is thereby performed. Even if you increase the upstream transmission rate,
The out-of-band spurious component is not deteriorated and the communication distance with the base station is not shortened.

Further, according to the present invention, in the transmission power control circuit for controlling the power intensity of the transmission signal capable of code multiplexing by the direct spread method according to the power intensity of the reception signal, the multiplexing for detecting the code multiplexing number of the transmission signal. Number detection means, amplification means for amplifying the power of the transmission signal, gain control means for controlling the gain of the amplification means according to the power intensity of the reception signal,
Maximum power intensity for controlling the amplifying means according to the number of code multiplexes detected by the multiplex number detecting means so that the maximum value of the power intensity of the transmission signal amplified by the amplifying means becomes a value according to the number of code multiplexes. The control means and the characteristic control means for controlling the gain characteristic of the amplifying means according to the number of code multiplexes detected by the multiplex number detecting means and varying the saturation level thereof are configured.

In the transmission power control circuit having the above structure, the code multiplex detected by the multiplex number detecting means is set so that the maximum value of the power intensity of the transmission signal amplified by the amplifying means becomes a value corresponding to the number of code multiplexes. While controlling the amplification means according to the number,
The saturation characteristic is made variable by controlling the gain characteristic of the amplifying means in accordance with the number of code multiplexes of the transmission signal.

Therefore, according to the transmission power control circuit having the above configuration, the maximum value of the power intensity of the transmission signal amplified by the amplifying means becomes a value according to the number of code multiplexes, and also according to the number of code multiplexes of the transmission signals. Since the gain characteristic of the amplifying means can be changed, the saturation of the amplifying ability due to the increase in the number of multiplexes is prevented,
As a result, even if code multiplexing is used to increase the uplink transmission rate, deterioration of out-of-band spurious components and shortening of the communication distance with the base station will not occur.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a transmission power control circuit according to the first embodiment of the present invention.

The variable reception gain amplifier 101 amplifies the reception signal according to a gain control signal s1 described later. The received signal amplified here is input to the modem receiving unit 102 and the power detection circuit 103.

The modem receiving section 102 demodulates the received signal which has been code-spread. On the other hand, the power detection circuit 10
At 3, the received signal is converted into a DC signal (power detection signal) corresponding to the power level. This power detection signal is
The reference DC signal Pref which is the control target in the subtraction circuit 104
And the difference is taken as an error signal
It is output to 05. This error signal is integrated by the integrating circuit 105 and becomes the gain control signal s1 of the reception gain variable amplifier 101 described above.

In this way, the variable reception gain amplifier 101,
Since the control loop including the power detection circuit 103, the subtraction circuit 104, and the integration circuit 105 operates so that the error signal approaches 0, the power detection signal is substantially equal to Pref even if the level of the reception signal changes. The gain of the variable reception gain amplifier 101 is controlled so that

Modem receiving section 102 extracts a power control signal transmitted from the base station for performing closed loop control from the received signal and inputs it to closed loop control circuit 109.

The closed loop control circuit 109, based on the information of the above power control signal, has a variable transmission gain amplifier 10 described later.
The correction value of the gain control signal s1 to 8 is input to the adding circuit 106. In the adding circuit 106, the correction value from the closed loop control circuit 109 is added to the gain control signal s1 obtained by the integrating circuit 105, and the gain control signal s1 is input to the limiter circuit 107.

The transmission signal modulated by code spreading in the modem transmission unit 111 is input to the transmission gain variable amplifier 108. Further, the modem transmitter 111 notifies the limit value setting circuit 112 of the code multiplexing number n of the transmission signal.
When n is “1”, it means that one spreading code is used without multiplexing.

The limit value setting circuit 112 notifies the limiter circuit 107 of the limit value Ln corresponding to the code multiplex number n notified from the modem transmitting unit 111. As shown in FIG. 2, the limiter circuit 107 converts the gain control signal s1 corrected by the adder circuit 106 into a gain control signal s2 and outputs it to the transmission gain variable amplifier 108.

That is, the limiter circuit 107 inputs the gain control signal s1 corrected by the adder circuit 106 to the transmission gain variable amplifier 108 as the gain control signal s2. The gain control signal s1 is the limit value setting circuit 112.
When the limit value Ln set by the above is exceeded, the gain control signal s2 having the limit value Ln is transmitted to the transmission gain variable amplifier 1
Enter in 08.

The variable transmission gain amplifier 108 amplifies the transmission signal modulated by code spreading in the modem transmission section 111 according to the gain control signal s2 from the limiter circuit 107 and inputs it to the power amplifier (PA) 110. . The power amplifier 110 amplifies the transmission signal amplified by the transmission gain variable amplifier 108 with a predetermined gain.

That is, in the transmission power control circuit having the above structure, when the transmission signal power is controlled by the transmission gain variable amplifier 108, the gain control signal s2 for controlling the gain according to the increase of the code multiplexing number n. Upper limit value (limit value) Ln
I try to make it smaller.

As a result, an increase in the ratio between the peak value and the average value of the transmission signal amplified by the transmission gain variable amplifier 108 is suppressed, and the out-of-band spurious component is deteriorated due to the saturation of the amplification capability of the power amplifier 110 in the subsequent stage. Suppress.

Therefore, according to the transmission power control circuit having the above configuration, the out-of-band spurious component does not deteriorate even if the uplink transmission rate is increased by code multiplexing.
In the transmission power control circuit configured as described above, the limit value is fixed when the code multiplexing number n is 6 or more, as shown in FIG. This is because the increase rate of the ratio between the peak value and the average value of the transmission signal tends to decrease as the code multiplexing number n increases to some extent.

Next, a transmission power control circuit according to the second embodiment of the present invention will be described. FIG. 3 shows its configuration. Here, the same parts as those of the transmission power control circuit shown in FIG. 1 are designated by the same reference numerals, and different parts will be mainly described here.

In the adder circuit 106, the gain control signal s1 obtained by the integrating circuit 105 is added to the closed loop control circuit 109.
The correction value from is added and input to the limiter circuit 207.

The limiter circuit 207 is the addition circuit 10 described above.
The gain control signal s1 corrected in 6 is converted into the gain control signal s2.
When the gain control signal s1 is greater than or equal to a preset limit value L0, the gain control signal s2 having the limit value L0 is input to the transmission gain variable amplifier 108.

The transmission signal modulated by code spreading in the modem transmission unit 211 is input to the transmission gain variable amplifier 108. Further, the modem transmission unit 211 notifies the bias variable circuit 213 of the code multiplexing number n of the transmission signal. When n is “1”, it means that one spreading code is used without multiplexing.

The variable transmission gain amplifier 108 amplifies the transmission signal modulated by code spreading in the modem transmission unit 211 according to the gain control signal s2 from the limiter circuit 207 and inputs it to the power amplifier (PA) 210. .

The power amplifier 210 amplifies the transmission signal amplified by the transmission gain variable amplifier 108. The gain characteristic of the power amplifier 210 is the bias variable circuit 21.
Controlled by 3.

The bias variable circuit 213 changes the power supply voltage of the power amplifier 210 according to the code multiplex number n notified from the modem transmission unit 211, controls the gain characteristic thereof, and changes the saturation point. In this control, as the code multiplexing number n increases, the 1 dB gain compression point of the power amplifier 210 changes by increasing the power supply voltage of the power amplifier 210, as shown in FIG.

FIG. 5 shows an example of the bias variable circuit 213. For example, a DC / DC converter 2131 such as MAX879 made by MAMIM is used. This DC / D
The C converter 2131 is supplied with the operating voltage directly from the battery and via the inductor L1, and the OUT terminal is connected to the FB terminal via the resistor R1, and the difference between the voltage at the FB terminal and the reference voltage is OUT to be smaller
It controls the output voltage of the terminal.

A plurality of resistors R21 to R2n having different resistance values are connected to the FB terminal, and the selection circuit 2132 selects one of the resistors R21 to R2n according to the code multiplex number n. To ground the FB terminal.

As a result, according to the code multiplexing number n, the FB
The voltage of the terminal changes, and the DC / DC converter 2
131 controls the output voltage of the OUT terminal so that the difference between the voltage of the FB terminal and the reference voltage becomes small, so that the voltage corresponding to the code multiplex number n is supplied from the OUT terminal to the power amplifier 210. .

Here, the output voltage of the OUT terminal (power supply voltage of the power amplifier 210) is Vout, the reference voltage is Vref, the resistance value of the resistor R1 is r1, and the resistance value of the resistor selected by the selection circuit 2132 is. If r2, Vout is expressed by the following equation.

[0052]

[Equation 1]

It should be noted that the selection circuit 2132 uses the code multiplex number n.
As the number of resistors increases, the resistors R21 to R2n
Connect the resistors with smaller resistance values in order, and
Increase the output voltage Vout of the T terminal.

As described above, in the transmission power control circuit having the above-described configuration, the power amplifier 2 increases in accordance with the increase in the code multiplexing number n.
The power supply voltage Vout of 10 is increased to increase the power amplifier 21.
The gain saturation level of 0 is increased.

Therefore, according to the transmission power control circuit configured as described above, even if the code multiplexing number n is increased to increase the uplink transmission rate, the amplification capability of the power amplifier 210 is not saturated, so that the out-of-band spurious component is generated. Since it does not deteriorate and the transmission power itself does not decrease,
The communication distance with the base station does not become short.

The bias variable circuit 213 is not limited to the form shown in FIG. For example, the selection circuit 2132 described above uses the resistor R according to the code multiplexing number n.
It is assumed that any one of 21 to R2n is selected,
Instead of this, for example, a plurality of resistors are selected from the resistors R21 to R2n as the code multiplexing number n increases, the combined resistance of the resistors is reduced, and the output voltage Vout of the OUT terminal is increased. May be. It goes without saying that the gain characteristic of the power amplifier 210 may be controlled by a method other than the variable power supply voltage.

Further, as shown in FIG. 6, the method used in the first embodiment and the method used in the second embodiment may be used together. According to this, the code multiplexing number n
More flexibility can be provided by setting the maximum output power and the limit value with respect to. Needless to say, the present invention can be similarly implemented even if various modifications are made without departing from the scope of the present invention.

[0058]

As described above, according to the present invention, the multiplex number detecting means detects the maximum value of the power intensity of the transmission signal amplified by the amplifying means in accordance with the code multiplex number. The amplification means is controlled in accordance with the code multiplexing number and the gain characteristic of the amplification means is controlled in accordance with the code multiplexing number of the transmission signal so that the saturation level can be varied.

Therefore, according to the present invention, the maximum value of the power intensity of the transmission signal amplified by the amplifying means becomes a value according to the code multiplex number, and the gain of the amplifying means according to the code multiplex number of the transmitting signal. As the characteristics can be changed, saturation of the amplification capacity due to an increase in the number of multiplexes is prevented, and even if the uplink transmission rate is increased by code multiplexing, deterioration of out-of-band spurious components and shortening the communication distance with the base station are possible. It is possible to provide a transmission power control circuit that does not cause a change.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a configuration of a first embodiment of a transmission power control circuit according to the present invention.

FIG. 2 is a diagram for explaining limit value control of a transmission gain variable amplifier of the transmission power control circuit shown in FIG.

FIG. 3 is a circuit block diagram showing a configuration of a second embodiment of a transmission power control circuit according to the present invention.

FIG. 4 is a diagram for explaining a saturation level control of a power amplifier of the transmission power control circuit shown in FIG.

5 is a circuit block diagram showing a configuration of a bias variable circuit of the transmission power control circuit shown in FIG.

FIG. 6 is a circuit block diagram showing another configuration example of the transmission power control circuit according to the present invention.

FIG. 7 is a diagram for explaining a process of generating an upstream signal directed to a base station.

8 is a diagram showing a vector waveform of an orthogonal signal generated by the processing of FIG.

FIG. 9 is a circuit block diagram showing a configuration of a conventional transmission power control circuit.

10 is a diagram for explaining gain control of a variable reception gain amplifier of the conventional transmission power control circuit shown in FIG.

11 is a diagram for explaining gain control of a transmission gain variable amplifier of the conventional transmission power control circuit shown in FIG.

FIG. 12 is a diagram for explaining a process of multiplex-generating an upstream signal directed to a base station.

[Explanation of symbols]

101 ... Variable reception gain amplifier 102 ... Modem receiver 103 ... Power detection circuit 104 ... Subtraction circuit 105 ... Integrating circuit 106 ... Adder circuit 107, 207 ... Limiter circuit 108 ... Variable transmission gain amplifier 109 ... Closed loop control circuit 110, 210 ... Power amplifier (PA) 111, 211 ... Modem transmission unit 112 ... Limit value setting circuit 213 ... Bias variable circuit 2131 ... Converter 2132 ... Selection circuit

Claims (6)

(57) [Claims] 1. A transmission power control circuit for controlling the power intensity of a transmission signal capable of code multiplexing by a direct spreading method according to the power intensity of a reception signal, wherein a multiplex number detecting means for detecting the code multiplex number of said transmission signal. And an amplification means for amplifying the power of the transmission signal, and a gain of the amplification means according to the power intensity of the reception signal.
The gain control means for controlling the maximum power intensity of the transmission signal amplified by the amplifying means.
The multiplex so that the value becomes a value according to the number of code multiplexes.
According to the code multiplex number detected by the number detecting means,
And a maximum power intensity control means for controlling the stage . 2. A transmission power control circuit for controlling the power intensity of a transmission signal capable of code multiplexing by a direct spread method according to the power intensity of a received signal, the multiplex number detecting means detecting the code multiplex number of the transmission signal. And an amplification means for amplifying the power of the transmission signal, and a gain of the amplification means according to the power intensity of the reception signal.
In accordance with the gain control means for controlling, and the code multiplex number detected by the multiplex number detecting means,
A transmission power control circuit comprising: a characteristic control unit that controls a gain characteristic of the amplification unit to change a saturation level thereof. 3. A transmission power control circuit for controlling the power intensity of a transmission signal capable of code multiplexing by a direct spread method according to the power intensity of a received signal, wherein a multiplex number detecting means for detecting the code multiplex number of said transmission signal. And an amplification means for amplifying the power of the transmission signal, and a gain of the amplification means according to the power intensity of the reception signal.
The gain control means for controlling the maximum power intensity of the transmission signal amplified by the amplifying means.
The multiplex so that the value becomes a value according to the number of code multiplexes.
According to the code multiplex number detected by the number detecting means,
Maximum power intensity control means for controlling the stages, and according to the code multiplex number detected by the multiplex number detecting means,
A transmission power control circuit comprising: a characteristic control unit that controls a gain characteristic of the amplification unit to change a saturation level thereof. 4. The maximum power intensity control means controls the gain of the amplifying means so as to reduce the maximum power intensity of the transmission signal as the number of code multiplexes increases. Alternatively, the transmission power control circuit according to claim 3. 5. The characteristic control means controls the characteristic so as to increase the saturation level of the amplifying means as the number of code multiplexes increases. The transmission power control circuit described. 6. The power control included in the received signal.
A detection means for detecting a control signal, wherein the gain control means comprises:
Based on the power control signal detected by the detection means,
4. The method according to claim 1, wherein the gain of the width means is controlled.
The transmission power control circuit according to claim 5.