JPH10242905A - Step-type transmission power control circuit - Google Patents

Abstract

(57) [Problem] To provide a step-type transmission power control circuit that keeps a small amount of phase jump per control and does not cause deterioration of characteristics. SOLUTION: Up / down counter 1 for transmission power control
01 is the gain indicated by the TPC bit at the control timing of 2 ⁿ times faster than the conventional control timing of inputting the transmission power control bit (TPC bit) from the base station and inputting from the 2 ⁿ pulse generation circuit 104 in the closed loop control. Is output from the count output terminal as a conventional output bit + n bit count output in which one count corresponds to 1/2 ⁿ of the conventional control amount. The gain control circuit 102 changes the count output to a control voltage, and the variable gain amplifier 103 changes the gain based on the control voltage, amplifies the signal to be transmitted to the base station by the changed gain, and Deliver to the power amplifier. The control step and the control amount are finer, and the phase jump amount per control becomes smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to amplifying a signal to be transmitted to a base station with a gain indicated by the transmission power control bit in accordance with a control timing of a transmission power control bit transmitted from the base station at a constant period. And a step-type transmission power control circuit.

[0002]

2. Description of the Related Art Transmission power control is known as an interference reduction method in digital mobile communication, and transmission power control includes closed-loop control and open-loop control. In the conventional closed loop control, a transmission power control bit (TPC
There is a method in which a mobile station that receives the control signal controls the current transmission power in steps of ± several dB. The conventional method is applied to a step-type transmission power control circuit shown in FIG.

[0003] The step-type transmission power control circuit 500 comprises a transmission power control up / down counter 501, a gain control circuit 502, and a variable gain amplifier 503. An up / down counter 501 for transmission power control (hereinafter abbreviated as up / down counter 501) inputs an initial value from an initial value input terminal LD before entering closed loop control immediately after line connection. In the closed loop control, the up / down counter 501 inputs the TPC bit to the count data terminal UP / DOWN and the control terminal CK, uses the TPC bit insertion cycle (0.625 ms) as the control timing, and counts the count value based on the TPC bit. The value is incremented or decremented and output from the count output terminal to the gain control circuit 502.

The gain control circuit 502 converts, for example, 7 bits of the count value received from the up / down counter 501 into a DC voltage value, and the variable gain amplifier 503 sets a gain based on the DC voltage value and sets the gain. The input signal is amplified with the gain thus set and output to the power amplification section of the next stage. The number of constituent bits of the up / down counter 501 is determined by a desired transmission power control dynamic range. In the above case, since it is assumed that the dynamic range of 80 dB is controlled in 1 dB steps, the number of constituent bits is 7 bits.

[0005]

However, the above-mentioned step-type transmission power control circuit has a problem that the amount of delay of the variable gain amplifier changes depending on the attenuation or the set value of the power gain. That is, when the amount of attenuation changes at regular intervals, the phase of the signal is advanced or delayed instantaneously to generate a phase jump, and the modulation scheme of the transmission signal is QPSK.
In the case of such phase modulation, if the phase angle of the phase jump is large, there is a problem that characteristics are deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the control step and the control amount are made fine to keep the phase jump amount per control small.
An object of the present invention is to provide a step-type transmission power control circuit that does not cause deterioration in characteristics.

[0007]

In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a transmission power control bit instructed by a base station in accordance with a control timing of the transmission power control bit. Is output as a count output of a predetermined number of bits corresponding to one unit control amount, and a control voltage corresponding to the count output is output;
In a step-type transmission power control circuit for changing a gain corresponding to the control voltage and amplifying a signal to be transmitted to a base station with the changed gain, the control timing is set to 2
ⁿ (n is a natural number) times the 2 ⁿ number of pulse generating circuits for converting the control timing, and the count indicated by the transmission power control bit is 1/1 / (the unit control amount) according to the 2 ⁿ times control timing. A transmission power control up / down counter that outputs a count output of the predetermined bit + n bits corresponding to 2 ⁿ , a gain control circuit that outputs a control voltage corresponding to the count output of the transmission power control up / down counter, A variable gain amplifier that changes the gain in accordance with the control voltage of the gain control circuit and amplifies the signal to be transmitted to the base station with the changed gain.

Further, a second invention is a step-type transmission power control circuit having first and second step-type transmission power control circuits and an up-converter, wherein the first and second step-type transmission power control circuits are provided. The power control circuit is a step-type transmission power control circuit according to the first invention, wherein the variable gain amplifier of the first step-type transmission power control circuit amplifies a signal in an intermediate frequency band; The variable gain amplifier of the first stage-type transmission power control circuit converts the signal in the intermediate frequency band amplified to a signal in the high frequency band, and the variable gain amplifier of the second stage-type transmission power control circuit comprises the up-converter. Amplifies the converted high frequency band signal.

Further, the third invention uses a step attenuator instead of the variable gain amplifier.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing Embodiment 1 of a step-type transmission power control circuit according to the present invention. The step-type transmission power control circuit 100 performs transmission power control as an interference reduction method in digital mobile communication, and includes a transmission power control up / down counter 101, a gain control circuit 102, a variable gain amplifier 103, And 2 ⁿ pulse generation circuits 104.

Up / down counter for transmission power control 10
1 inputs an initial value from an initial value input terminal LD before entering closed loop control immediately after line connection. In the closed loop control, the up / down counter 101 inputs a transmission power control bit (TPC bit: insertion cycle T) inserted at a known timing of a fixed cycle from the base station through a dedicated physical channel to the count data end UP / DOWN, The count value is incremented or decremented on the basis of the TPC bit by a control timing 2 ⁿ times faster than the conventional one input from the 2 ⁿ pulse generation circuit 104 to the control terminal CK, and the count value obtained by increasing the configuration bits by n bits ( For example, a count value obtained by increasing 7 bits by n = 2 bits and setting it to 9 bits) is output to the gain control circuit 102 from the count output terminal. In this case, one count of the transmission power control up / down counter 101 corresponds to a control amount of 1/2 ⁿ of the conventional control amount. Gain control circuit 102
Changes the count output to a control voltage, the gain variable amplifier 103 changes the gain based on the control voltage, amplifies the signal to be transmitted to the base station by the changed gain, and sends the amplified signal to the next-stage power amplifier. Output.

That is, the above-described increase in the number of configuration bits is not intended to increase the dynamic range, but is intended to reduce the control steps and control amounts. So, for example, what was the conventional 1 dB step (see FIG. 2) is now 1 dB / 2 ⁿ ,
When n = 2, 1 dB / 4 = 0.25 dB step control is performed. Also, since the control timing of the 2 ⁿ pulse generation circuits 104 is as fine as T / 2 ⁿ , 0.625 ms
/ ^2n, ie, 0.625 / 4 = 0.15625 ms
Becomes

FIG. 2 schematically shows this control state, in which the ideal linear control is indicated by a dashed line, and the conventional control having a large control step and control amount is indicated by a dotted line. The circuit according to the first embodiment of FIG. 1 is shown by a solid line. Therefore, the first embodiment is closer to the ideal than the conventional one, and the control step and the control amount can be finely changed, so that the phase jump per one control can be suppressed small, and the phase jump is equal to the transmission power control period. , The so-called inter-symbol phase error is suppressed to a very small level, and deterioration of the quality when the signal is demodulated on the receiving side is prevented. In particular, in the receiving system, when using a detection method that has the effect of suppressing fading fluctuation such as pilot interpolation synchronous detection,
It is possible to absorb a phase error due to transmission power control. Although the variable gain amplifier 103 is used in FIG. 1, the same can be performed by using a step attenuator instead.

(Embodiment 2) FIG. 3 is a block diagram showing Embodiment 2 of a step-type transmission power control circuit according to the present invention. The stage transmission power control circuit 200 includes a first stage transmission power control circuit 210 and a second stage transmission power control circuit 220 that operate in parallel, and an up converter 230. The first stage transmission power control circuit 210 includes a transmission power control up / down counter 211, a gain control circuit 212, a variable gain amplifier 213, and 2 ⁿ pulse generation circuits 214. The second stage transmission power control circuit 220 includes a transmission power control up / down counter 221, a gain control circuit 222, a variable gain amplifier 223, and 2 ⁿ pulse generation circuits 224.

First and second stage transmission power control circuit 21
The operations of 0 and 220 are the same as the operations of the step-type transmission power control circuit 100 in FIG. 1, respectively, and thus the detailed description of the operations here is omitted. The variable gain amplifier 213 of the first stage type transmission power control circuit 210 receives an IF band signal, amplifies the signal with the gain specified by the gain control circuit 212, and outputs the amplified signal to the up-converter 230. Upconverter 2
30 up-converts the input IF band signal into an RF band signal, and outputs the signal to the variable gain amplifier 223 of the second stage transmission power control circuit 220. Variable gain amplifier 22
Reference numeral 3 amplifies the input RF band signal with the gain specified by the gain control circuit 222, and outputs the amplified signal to the power amplifier of the next stage.
As described above, since the amplification is performed separately for the intermediate frequency band and the high frequency band, accurate control can be performed.

[0016]

As described in detail above, the present invention relates to the first invention.
The step-type transmission power control circuit that is
According to the control timing of the transmitted transmission power control bit.
The gain indicated by the transmission power control bit is
Count of the specified number of bits corresponding to the unit control amount
Control voltage corresponding to this count output
And changes the gain in accordance with the control voltage.
Amplify the signal to be transmitted to the station with the changed gain.
In the step-type transmission power control circuit, the control timing
To the secondⁿConverted to (n is a natural number) times control timing
Do 2ⁿA pulse generating circuit;ⁿDouble control time
Gain indicated by the transmission power control bit according to the
Is one-half of the unit control amount.ⁿBefore responding to
Output as a predetermined bit + n-bit count output
Up / down counter for transmission power control, and the transmission power
Corresponds to the count output of the control up / down counter
Gain control circuit for outputting a control voltage, and the gain control circuit
The gain is changed according to the control voltage of
Variable gain increase for amplifying the signal to be output with the changed gain
By having a width gauge, the control
And control amount are reduced by half ⁿAnd control once
Phase jump amount can be reduced, and characteristics such as phase modulation
This has the effect of controlling the transmission power without deteriorating.
You.

Further, the step-type transmission power control circuit according to the second invention comprises: first and second step-type transmission power control circuits;
An up-converter and a step-type transmission power control circuit, wherein the first and second step-type transmission power control circuit,
A step-type transmission power control circuit according to the first invention,
The variable gain amplifier of the first stage type transmission power control circuit amplifies an intermediate frequency band signal, and the up converter includes an intermediate frequency band amplified by the variable gain amplifier of the first stage type transmission power control circuit. Is converted to a signal in a high frequency band, and the variable gain amplifier of the second stage type transmission power control circuit amplifies the signal in the high frequency band converted by the up-converter, thereby obtaining the same signal as in the first invention. In addition to the effect, the amplification is performed separately in the case of the intermediate frequency band and the case of the high frequency band, so that accurate control can be performed, and the quality after demodulation is improved.

Further, the step-type transmission power control circuit according to the third aspect of the invention uses a step attenuator in place of the variable gain amplifier, thereby providing an effect that the control amount can be changed simply and accurately.

[Brief description of the drawings]

FIG. 1 is a block diagram showing Embodiment 1 of a step-type transmission power control circuit according to the present invention.

FIG. 2 shows a control state of a step-type transmission power control circuit of FIG. 1;
9 is a graph schematically showing a comparison with a control state of a conventional step-type transmission power control circuit.

FIG. 3 is a block diagram showing Embodiment 2 of a step-type transmission power control circuit according to the present invention.

FIG. 4 is a block diagram showing a conventional example of a step-type transmission power control circuit.

[Explanation of symbols]

100,200 step type transmission power control circuit 101,211,221 Up / down counter for transmission power control 102,212,222 Gain control circuit 103,213,223 Variable gain amplifier 104,214,224 2 ⁿ pulse generation circuit 210 1st stage transmission power control circuit 220 2nd stage transmission power control circuit 230 Upconverter

Claims (3)

[Claims] 1. A gain indicated by the transmission power control bit is output as a count output of a predetermined number of bits corresponding to a unit control amount in accordance with a control timing of the transmission power control bit transmitted from the base station at a constant period. And outputting a control voltage corresponding to the count output, changing a gain in accordance with the control voltage, and amplifying a signal to be transmitted to the base station with the changed gain in a step-type transmission power control circuit. , 2 ⁿ number pulse generating circuit and the (n is a natural number) control timing Part 2 ⁿ is converted to double the control timing, the following control timing of the 2 ⁿ times, instructs the gain to one count of the transmission power control bits said predetermined bits + n transmission power control up-down counter that outputs a count output bits corresponding to 1/2 ⁿ of the unit control amount A gain control circuit which outputs a control voltage corresponding to the count output of the transmission power control up-down counter, to change the gain in response to the control voltage of the gain control circuit,
And a variable gain amplifier for amplifying a signal to be transmitted to the base station with the changed gain. 2. A step-type transmission power control circuit having first and second step-type transmission power control circuits and an up-converter, wherein the first and second step-type transmission power control circuits each include: 2. The step-type transmission power control circuit according to claim 1, wherein the variable gain amplifier of the first step-type transmission power control circuit amplifies a signal in an intermediate frequency band, and the up-converter is the first step-type transmission power control circuit. The intermediate frequency band signal amplified by the variable gain amplifier of the transmission power control circuit is converted into a high frequency band signal, and the variable gain amplifier of the second stage type transmission power control circuit converts the high frequency band signal converted by the up converter. A step-type transmission power control circuit that amplifies signals. 3. A step-type transmission power control circuit using a step attenuator instead of the variable gain amplifier.