JPH11154927A - Spectrum spread communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an equipment capable of reducing power consumption without the deterioration of an error rate by compensating the amplitude restriction of each channel according to the power of each channel even at the time of executing the amplitude restriction of a multiplex signal through the use of the transmitting power amplifier having a narrow dynamic range. SOLUTION: Through the use of the transmitting power amplifier of a dynamic range, the amplitude restriction of each channel is compensated according to the power of each channel even at the time of executing the amplitude restriction of a multiplex signal. Relating to this spectrum spread communication equipment, a control signal generating circuit 108 generates a control signal compensating the power varying quantity of the transmitting signal of each channel compensating the power varying quantity of the transmitting signal of each channel 1 to N. A volume circuit 110 variably controls the amplitude of the transmission signal of each channel 1 to N so as to compensate based on the control signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spread spectrum communication apparatus capable of effectively controlling transmission power without deteriorating error rate characteristics.

[0002]

2. Description of the Related Art FIG. 11 shows a configuration of a transmission section of a conventional spread spectrum communication apparatus. Such a transmission unit is used, for example, in a base station of a mobile communication system. The signals on each of channels 1 to N are
In step 1, the information is incorporated into a transmission frame format accompanied by various control information. After that, the transmission frame format is spread by the spreading code assigned to each channel in the spreading modulation circuit 1102. The spread output from the spreading modulation circuit 1102 for each channel is combined into one system as a multiplexed signal by the multiplexing circuit 1103 and sent to the nonlinear amplitude control circuit 1104.

In this device example, QPSK (Quadrat)
ure phase shift keying) or the like, so that a spread modulation circuit 1102 for each channel is used.
And the output of the multiplexing circuit 1103 are composed of two systems of an I component and a Q component. In the nonlinear amplitude limiting circuit 1104,
The amplitude is limited to the amplitude limit level according to the number of currently multiplexed channels. The amplitude-limited multiplexed signal is D
Is converted into an analog signal by the / A conversion circuit 1106,
The signal is mixed with a carrier signal from a carrier generation circuit 1108 by a mixer 1107, converted into a modulated signal, amplified by a transmission power amplifier 1109, and transmitted from a transmission antenna 1110.

Next, the nonlinear amplitude limiting circuit 1104 will be described. When a binary code represented by +1 or -1 is used as a spreading code, a multiplexed signal in which N channels are multiplexed has amplitude values from -N to N. In order to maintain the cross-correlation characteristics of each channel, it is necessary to store this amplitude value without deteriorating it until it is despread by a receiving unit (not shown). However, when the number N of channels is large, the probability that a multiplexed signal having a large amplitude value is generated becomes small, so that it is not always necessary to strictly store the amplitude value.

[0005] By utilizing this property, a large-amplitude part that is less frequently generated is discarded at an optimum amplitude control level obtained from computer simulation, thereby suppressing the deterioration of the error rate characteristic and increasing the required dynamic range of the power amplifier 1109. This can be set low, and power consumption and cost can be reduced.

[0006]

However, in the conventional spread spectrum communication apparatus using the above-described nonlinear amplitude limiting circuit, only the case where all the signals of each channel have the same power is considered. The effect of the non-linear amplitude limitation in the case where there is variation is not considered. On the other hand, in the spread spectrum communication apparatus, since there is a near-far problem, a large amount of power is allocated to a mobile station channel far away from the base station in order to keep the channel capacity constant, and a mobile station near the base station is used. Transmission power control for each channel, such as allocating a small amount of power to a channel and transmitting it, is an essential technology.

Under such transmission power control for each channel, if the uniform amplitude limitation is performed on each channel as shown in the above-mentioned conventional example, the influence of the deterioration of the cross-correlation characteristic of the spreading code of each channel is small. There is a problem that the larger the channel to which power is allocated, the larger the error rate of the low power channel is.

The present invention has been made to solve such a conventional problem. It is possible to effectively limit the amplitude even under the transmission power control for each channel, and to set the dynamic range of the transmission power amplifier low. It is another object of the present invention to provide a spread spectrum communication apparatus capable of reducing power consumption without causing an error rate degradation.

[0009]

In a spread spectrum communication apparatus according to the present invention, the amplitude of a transmission signal of a plurality of channels spread by a spread code different for each channel is limited to a predetermined amplitude limit set value. When generating a multiplexed signal and transmitting the multiplexed signal after power amplification, a control signal generation circuit that generates a control signal for controlling the amplitude of the transmission signal of each channel, and a transmission signal of each channel based on the control signal A plurality of volume circuits for variably controlling the amplitude, a transmission multiplexing circuit for multiplexing the transmission signals of the respective variably controlled channels, and generating a multiplexed signal,
A non-linear amplitude limiting circuit for limiting the amplitude of a portion exceeding the amplitude limit set value in the multiplexed signal to be equal to or less than the set value, wherein the control signal generation circuit includes an average power information and an amplitude of a transmission signal of each channel. From the limit setting value, a control signal for compensating the power fluctuation amount of the transmission signal of each channel due to the amplitude limitation of the multiplex signal is generated, and the volume circuit, based on the control signal, Is variably controlled so as to compensate for.

[0010] Further, based on transmission signals of a plurality of channels spread spectrum by a spreading code different for each channel,
A control signal generating circuit that generates a multiplexed signal whose amplitude is limited to a predetermined amplitude limit set value and transmits the multiplexed signal after power amplification and generates a control signal for controlling the amplitude of the transmission signal of each channel, A plurality of volume circuits that variably control the amplitude of the transmission signal of each channel based on the control signal, and a transmission multiplexing circuit that multiplexes the transmission signal of each variably controlled channel and generates a multiplexed signal, The control signal generation circuit compensates for the power fluctuation amount of the transmission signal of each channel due to the amplitude limitation of the multiplex signal from the average power information and the amplitude limit setting value of the transmission signal of each channel, and Generating a control signal for limiting the amplitude of the transmission signal of each channel so that the amplitude of the portion exceeding the amplitude limit set value can be limited to the set value or less; Arm circuit, based on said control signal,
The variable control is performed so as to compensate and limit the amplitude of the transmission signal of each channel.

Further, the compensation of the amplitude of the transmission signal of each channel is weighted according to the average power of the transmission signal of each channel.

The compensation of the amplitude of the transmission signal of each channel is controlled temporally in accordance with the frequency at which the multiplex signal exceeds the amplitude limit set value.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a transmitting section of a spread spectrum communication apparatus according to Embodiment 1 of the present invention. In FIG. 1, 101 is each channel 1 to
A frame assembling circuit for incorporating a signal for each N into a transmission frame format accompanied by various control information and the like;
Reference numeral 102 denotes a spread modulation circuit that performs spread modulation on a transmission signal assembled into a frame, and reference numeral 103 denotes a multi-level circuit that weights each channel in order to control transmission power of the spread-modulated transmission signal.

Reference numeral 104 denotes a control signal generation circuit 108 described later.
A reference control timing circuit for supplying a reference timing to the reference signal; 105, an average power control circuit for each channel that supplies power information such as the average power of each channel to the control signal generation circuit 108; 106, the number of multiplexed channels and each channel; Is an amplitude limit value setting circuit that calculates an amplitude limit value from the average power of the control signal and sends it to the control signal generation circuit 108.

A control signal generating circuit 107 multiplexes a plurality of multi-valued transmission signals and generates a multiplexed signal for control.
A control multiplexing circuit 108 outputs a control signal based on the multiplexing signal for control, average power information of each channel, and an amplitude limit setting value, and outputs the control signal to a volume circuit 110 described later. , 109 is a delay circuit that delays the signal of each channel by the delay time generated for the generation of the control signal and synchronizes the control signal with the transmission signal, and 110 increases or decreases the amplitude of the transmission signal of each channel by the control signal. It is a volume circuit.

Reference numeral 111 denotes a transmission multiplexing circuit for code-division multiplexing a multi-level transmission signal of a plurality of channels, 112 denotes a non-linear amplitude limiting circuit for limiting the amplitude so as to compensate for the shortage of the dynamic range of the transmission power amplifier 116, and 113 Is D / which converts a multiplex signal, which is a digital signal, into an analog signal.
An A conversion circuit 115 mixes the analog signal with the carrier signal from the carrier generation circuit 114 and outputs a modulated signal. A mixer 116 amplifies the transmission signal mixed by the mixer 115 and a transmitter 117 amplifies the transmission signal. Antenna.

Next, the operation of the first embodiment will be described. In this embodiment, since a quadrature modulation scheme such as the QPSK scheme is used, the spread modulation circuit 1 for each channel is used.
02, multi-level circuit 103, delay circuit 109, volume circuit 110, transmission multiplexing circuit 111, control multiplexing circuit 1
07 and the output of the control signal generation circuit 108 are I component and Q
It consists of two systems of components. The signals on each of the channels 1 to N are incorporated by the frame assembling circuit 101 into a transmission frame format accompanied by various control information and the like. After that, the transmission frame format is spread by the spreading modulation circuit 102 using a spreading code assigned to each channel.

The spread transmission signal is supplied to a multi-level conversion circuit 103.
In, a signal amplification or attenuation weighting operation is performed so that the required power of the channel is obtained. The signal weighted through the multi-level circuit is branched to a delay circuit 109 and a control multiplexing circuit 107. The signals input to the control multiplexing circuit 107 are combined into respective I and Q systems and sent to the control signal generation circuit 108 as control multiplexed signals.

On the other hand, each channel average power control circuit 105
Now, control the average power of each channel currently transmitting.
In addition to the original control of monitoring, the control signal generation circuit 108
Output the average power information of each channel. The amplitude limit value setting circuit 106 calculates an optimum amplitude limit value from the total number of transmission channels and the average power of each channel, and outputs the amplitude limit value to the control signal generation circuit 108 and the nonlinear amplitude limit circuit 112. I do.

The control signal generation circuit 108 performs non-linear amplitude limitation on the basis of information such as a control multiplex signal, average power information of each channel, and an amplitude limitation set value in a reference timing unit from the reference control timing circuit 104. The power loss amount, which is the power fluctuation amount of each channel, is calculated. Then, the compensation amount of the lost power is obtained based on this calculation, and is output to the volume circuit 110 as a control signal.

On the other hand, the transmission signal output from the multi-level conversion circuit 103 is transmitted to a control signal generation circuit 108 by a delay circuit 109.
Are delayed by the time required to generate the control signal in the step S1. The volume circuit 110 compensates the delayed transmission signal for an amplitude value based on the control signal from the control signal generation circuit 108 over a reference timing time. After that, the transmission signals whose amplitude values have been compensated are combined into I and Q systems by the transmission multiplexing circuit 111.

The nonlinear amplitude limiting circuit 112 limits the amplitude of the multiplexed signal multiplexed by code division according to the amplitude limit value specified by the amplitude limit value setting circuit 106. The multiplexed signal whose amplitude is limited is converted into an analog signal by a D / A conversion circuit 113, and a carrier wave oscillation circuit 114
, Is converted into a modulated signal, amplified by the transmission power amplifier 116, and transmitted from the transmission antenna 117.

Next, the control signal generation circuit 108 will be described. When transmission power control is performed in a transmission apparatus using the spread spectrum communication method, power variation occurs in each channel, so that a large power signal channel and a small power signal channel are multiplexed in the transmission multiplexing circuit 111. When limiting the amplitude of such a multiplexed signal, if the same amplitude limitation is performed as in the case where all channels have equal power, the effect of the amplitude limitation on the cross-correlation characteristic of a low-power signal channel is greater, and the error of that channel is increased. It has been confirmed by computer simulation that the rate characteristic significantly deteriorates.

Hereinafter, the deterioration of the small power signal channel due to the nonlinear amplitude limitation and the method of compensating the deterioration will be qualitatively described using a simple example limited to only the I system. FIG. 2 is an explanatory diagram of amplitude limitation by a conventional method. FIG. 2A shows CH0,
One-bit data of three channels CH1 and CH2 are spread using one cycle of a spreading code having a different chip length (spreading code length) of 16, and the spreading code "0" is "-1" and "1" is "1".
It is shown that channel multiplexing was performed after weighting a certain amplitude for each of them.

Assuming that this signal is transmitted without impairing the dynamic range, and is demodulated in each receiver using the spreading code of each channel, the correlation value is proportional to the weighted value of each channel. 2 (b). FIG. 2C shows the multiplexed signal in the case where the amplitude of the multiplexed signal is limited by removing the upper 1 bit (or, when the upper 1 bit is deleted, the signal of the +8 level is halved to +4). This is an example in which demodulation is performed, and the correlation value of CH1, which is a low power signal, is 2
It can be seen that one channel is more degraded.

Next, the case of the present invention will be described. FIG.
FIG. 4 is an explanatory diagram of amplitude limitation by the method of the first embodiment. Now, as shown in FIG. 2C, the amplitude of a part of the multiplexed signal is limited in units of spreading codes. As a result, CH1
Is degraded. However, in the case of the present embodiment, when weighting the signal of each channel, as shown in FIG.
In addition to 1), the compensation control for limiting the amplitude was performed in consideration of the compensation amount (= 5/4). As a result, it can be seen that the deterioration amount of the correlation value is improved as compared with the conventional case of FIG. Further, CH0 by compensation control of the amplitude limit for CH1,
It can be seen that the effect of CH2 on the correlation value is very small as compared with the improvement amount of CH1.

As described above, in addition to the above-mentioned weighting, the amplitude is further compensated for the small power signal in the signal section where the amplitude is limited (for example, the section set at the reference timing such as the spread code cycle). Thereby, it is possible to improve the deterioration of the error rate of the small power signal due to the amplitude limitation.

In this example, the case where the amplitude limitation is a loss for CH1 has been described. However, on the contrary, the effect of the amplitude limitation may appear as an excessive correlation value after demodulation (the power fluctuation amount is +). In this case, this excess component becomes an interfering element for other channels. Therefore, in this case, the excess of the correlation value of CH1 may be obtained, and the amplitude may be attenuated to cancel the excess. Further, when there are a plurality of amplitude-limited portions in the section set at the reference timing, CH
It is determined whether the loss is 1 or excessive, and if the result of integrating them is negative, the volume control is performed on the volume 110 to amplify the loss and attenuate the excess if it is positive.

Hereinafter, a detailed configuration of the control signal generation circuit will be described. FIG. 4 shows a configuration per channel of the control signal generation circuit according to the first embodiment of the present invention. Reference numeral 401 denotes a gate circuit for determining whether to perform compensation control on a signal of a corresponding channel, and reference numeral 402 denotes a gate circuit 401.
A despreading circuit for despreading the multiplexed signal from the multiplexed signal; an amplitude limit value excess amount detection circuit for detecting an excess amount from the amplitude limit value of the despread multiplexed signal; This is an integrating / averaging circuit that calculates an average value and generates a control signal.

Next, the detailed operation of the control signal generation circuit will be described. The multiplexed signal output from the control multiplexing circuit 107 is input to the gate circuit 401. In this gate circuit, the multiplex signal is cut off or passed by the enable signal from each channel average power control circuit 105, and it is determined whether or not to perform compensation control on the own channel. The multiplexed signal that has passed through the gate circuit is sent to a
In step 2, despreading is performed at each reference timing by a spreading code obtained by spreading data of the own channel at the time of transmission. By this operation, the multiplexed signal is inverted when the spreading code is “0”, and is converted into a non-inverted waveform when the spreading code is “1”.

The amplitude limit value excess amount detection circuit 403 compares the despread waveform with the amplitude limit value within the reference timing, and if the despread waveform exceeds the amplitude limit value, detects the excess amount. The excess amount is obtained as a positive or negative value because it is despread in the despreading circuit 402. If the despread signal is smaller than the amplitude limit value, there is no excess amount.
Is output. The integrating and averaging circuit 404 integrates the obtained excess amount within the reference timing and averages it over the reference timing time. Through the above operation, the average value of the loss or excess amount of the own channel within the reference timing due to the amplitude limitation is obtained, and this value is output to the volume circuit 110 of the own channel as a control signal.

In the volume circuit, the attenuation control is performed in accordance with the value designated by the control signal in a unit of the reference timing, when the control signal is a positive value, and when the control signal is a negative value, the amplification control is performed. By performing the above control for all transmission channels, it is possible to realize compensation control for limiting the amplitude.

The invention of Embodiment 1 is configured as described above, and performs "amplitude limit compensation" for each signal channel in accordance with the power of each signal channel. This has the effect of preventing the error rate from deteriorating.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to the drawings. In the first embodiment (FIG. 1), the amplitude limitation of the multiplexed signal is performed by the nonlinear amplitude limiting circuit 112. In the second embodiment, however, the amplitude limitation and the amplitude limitation are simultaneously performed by the volume circuit in the volume circuit. . FIG. 5 shows the configuration of the transmitting section of the spread spectrum communication apparatus according to Embodiment 2 of the present invention. In FIG. 5, 5
01 is a frame assembling circuit provided for each channel, 502 is a spread modulation circuit that performs spread modulation on a transmission signal assembled into a frame, and 503 is a multi-level coding that weights each channel to perform transmission power control. Circuit.

Reference numeral 504 denotes a control signal generation circuit 508 to be described later.
Reference control timing circuit that supplies various timings to
Reference numeral 505 denotes an average power control circuit for each channel that supplies power information such as average power for each channel to the control signal generation circuit 508;
A control signal generation circuit 506 calculates an amplitude limit setting value from the number of channels to be multiplexed and the average power of each channel.
8 is an amplitude limit value setting circuit to be sent out.

A control multiplexing circuit 507 multiplexes a plurality of multi-valued transmission signals and outputs the multiplexed signals to a control signal generating circuit 508. 508 denotes a multiplexed signal, average power information of each channel, and an amplitude limit setting value. , A control signal for performing compensation by the amplitude limitation is generated, and the volume circuit 510
A control circuit 509 outputs a control signal, and a delay circuit 509 delays the signal of each channel by a delay time generated for generating the control signal to synchronize the control signal with the transmission signal. 510 increases or decreases the amplitude of each channel by the control signal. Is a volume circuit that performs the following.

Reference numeral 511 denotes a transmission multiplexing circuit for code-division multiplexing multi-level transmission signals of a plurality of channels, 512 a D / A conversion circuit for converting a digital multiplexed signal into an analog signal, 513 a mixer, and 514 a mixer. Carrier generation circuit, 5
Reference numeral 15 denotes a transmission power amplifier that amplifies the transmission signal mixed by the mixer 513, and 516 denotes a transmission antenna.

Next, the operation of the second embodiment will be described. In this embodiment, since a quadrature modulation method such as the QPSK method is used, the spread modulation circuit 50 for each channel is used.
2. Multi-level circuit 503, delay circuit 509, volume circuit 510, transmission multiplexing circuit 511, control multiplexing circuit 50
7. The output of the control signal generation circuit 508 is composed of two systems of an I component and a Q component. Each of the channels is incorporated into a transmission frame format with various types of control information by a frame assembling circuit 501, and then spread and spread.
Are spread by the spreading code assigned to the channel.

In order to perform transmission power control, the spread transmission signal is subjected to signal amplification or attenuation control in a multi-level conversion circuit 503 so that the required power of the channel is obtained. The signal weighted through the multi-level circuit 503 branches to a delay circuit 509 and a control multiplexing circuit 507. The signals input to the control multiplexing circuit 507 are collected into respective I and Q systems and sent to the control signal generation circuit 508.

On the other hand, each channel average power control circuit 505
The control and monitoring of the average power of each channel currently being transmitted is performed, and the average power information of each channel is output to the control signal generation circuit 508 at the same time. The amplitude limit value setting circuit 506 calculates an optimum amplitude limit value from the total number of transmission channels and the average power of each channel, and generates a control signal generation circuit 508.
Output the amplitude limit setting value.

The control signal generation circuit 508 uses the multiplexed signal, the average power information of each channel, the information such as the amplitude limit setting value, and the like, to determine the required attenuation in each spreading code unit for performing the non-linear amplitude limitation, The amount of power loss of each channel is calculated by limiting the amplitude in units of timing, and the compensation amount of the lost power is used as a control signal as a volume control circuit 510.
Output to

On the other hand, the transmission signal output from the multi-level circuit 503 and input to the delay circuit 509 is delayed by the time required to generate the control signal, and output to the volume circuit 510. In accordance with the control signal, the volume circuit 510 increases / decreases the amplitude in accordance with the amount of compensation in reference timing units, which is compensation control for amplitude limitation, and increases / decreases the amplitude in units of spread codes, which is amplitude limitation control. The signals subjected to the amplitude limitation and the compensation of the amplitude limitation are combined into I and Q systems by a transmission multiplexing circuit 511.

Thereafter, the multiplexed signal is converted to a D / A conversion circuit 512.
, Is mixed with a carrier signal from a carrier generation circuit 514 by a mixer 513, converted into a modulated signal, amplified by a transmission power amplifier 515, and transmitted from a transmission antenna 516.

Next, a detailed configuration of the control signal generation circuit 508 will be described. FIG. 6 shows Embodiment 2 of the present invention.
2 shows the configuration per channel of the control signal generation circuit. Reference numeral 601 denotes a gate circuit for determining whether or not to perform compensation control on the signal of the corresponding channel; 602, a despreading circuit for despreading the multiplexed signal from the gate circuit 601;
Is an amplitude limit value excess amount detection circuit for detecting an excess amount from the amplitude limit value of the despread multiplexed signal, 605 is an integration / average circuit for integrating the excess amount within a reference timing and calculating an average value, and 604 is A dividing circuit 607 for dividing the excess amount by the total number of channels, a delay circuit 607 for delaying the output of the dividing circuit by a reference time during which integration is performed, and a superimposing circuit 606 for superimposing the output of the delay circuit and the integrated average output. .

Next, the detailed operation of the control signal generation circuit will be described. The multiplexed signal output from the control multiplexing circuit 507 is input to the gate circuit 601. In this circuit, the multiplex signal is cut off or passed by the enable signal from each channel average power control circuit 505, and it is determined whether or not to perform amplitude limitation and compensation control on the own channel. The multiplexed signal that has passed through the gate circuit is subjected to despreading at a reference timing by a despreading circuit 602 using a spreading code obtained by spreading data of its own channel at the time of transmission by a spreading modulation circuit 502. By this operation, the multiplexed signal is inverted when the spreading code is “0”, and is converted into a non-inverted waveform when the spreading code is “1”.

The amplitude limit value excess amount detection circuit 603 compares the despread waveform with the amplitude limit value within the reference timing, and if the despread waveform exceeds the amplitude limit value, detects the excess amount. The excess amount is obtained as a positive or negative value because it is despread in the despreading circuit 602, and if the despread signal is smaller than the amplitude limit value, there is no excess amount.
Is output. Therefore, the output waveform of the amplitude limit value excess amount detection circuit is a waveform having an amplitude of "0" or an amplitude exceeding the amplitude limit value in spread code units.

The output waveform of the amplitude limit value excess amount detecting circuit is branched to a dividing circuit 604 and an integrating / averaging circuit 605. The integration and averaging circuit 605 integrates the obtained excess amount within the reference timing and averages it over the reference timing time. By this operation, the average value of the loss or excess amount of the own channel due to the amplitude limitation within the reference timing can be obtained.

On the other hand, the division circuit 604 divides the excess amount by the total number of transmission channels to calculate the required amplitude per channel so that the multiplexed signal does not exceed the amplitude limit value at the timing when it exceeds the amplitude limit value. Circuit 607
Is delayed by the reference time which is the integration time. The output of the integrating / averaging circuit 605 and the output of the delay circuit 607 are superimposed on the waveform by the superimposing circuit 606 at a timing synchronized with the reference timing, and output to the volume circuit 510 of each channel as a control signal.

The volume circuit performs attenuation control if the control signal is a positive value in units of spreading codes, and performs amplification control only if the control signal specifies a negative value if the control signal is a negative value. By performing the above control for all transmission channels, it is possible to realize amplitude limitation and amplitude limit compensation control.

The invention of the second embodiment is configured as described above. The volume circuit performs “amplitude limitation” and “compensation for amplitude limitation” for each channel in accordance with the power of each signal channel. Since it is performed, there is an effect that the error rate of the low power signal channel can be prevented from deteriorating. In addition, there is an effect that a non-linear amplitude limiting circuit becomes unnecessary and the configuration is simplified.

Embodiment 3 FIG. Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 7 shows the configuration of the transmitting section of the spread spectrum communication apparatus according to Embodiment 3 of the present invention. In FIG. 7, the configuration other than the control signal generation circuit 708 performs the same configuration and operation as in the first embodiment, and thus the control signal generation circuit 708 will be described below.

FIG. 8 shows a configuration per control channel of control signal generation circuit 708 according to the third embodiment of the present invention. Reference numeral 801 denotes a gate circuit for determining whether or not to perform compensation control on the signal of the corresponding channel; 802, a despreading circuit for despreading the multiplex signal; 803, an amplitude limit value for detecting an excess amount of the multiplex signal from the amplitude limit value. Excess amount detection circuit, 80
Reference numeral 4 denotes an integrating / averaging circuit for integrating the excess amount within the reference timing to obtain an average value, and 805 denotes a channel average power control circuit 70
5 is a weighting factor calculation circuit that calculates the weighting factor of the own channel from the average power information of each channel and the total transmission power information sent from the reference numeral 5, and 807 is a multiplication circuit that multiplies the output of the integration / averaging circuit 804 by the weighting factor.

Next, the detailed operation of the control signal generation circuit will be described. The multiplex signal output from the control multiplex circuit 707 is input to the gate circuit 801. In this circuit, the multiplex signal is cut off or passed by the enable signal from each channel average power control circuit 705, and it is determined whether or not to perform compensation control on the own channel. The multiplexed signal passed through the gate circuit 801 is sent to the despreading circuit
In step 2, despreading is performed at each reference timing by a spreading code obtained by spreading data of the own channel at the time of transmission. By this operation, the multiplexed signal is inverted when the spreading code is “0”, and is converted into a non-inverted waveform when the spreading code is “1”.

The amplitude limit value excess amount detection circuit 803 compares the despread waveform with the amplitude limit value within the reference timing, and if the despread waveform exceeds the amplitude limit value, detects the excess amount. The excess amount is obtained as a positive or negative value because it is despread in the despreading circuit 802, and is 0 when the despread signal is smaller than the amplitude limit value because there is no excess amount.
Is output. The integration and averaging circuit 804 integrates the obtained excess amount within the reference timing and averages it over the reference timing time.

When the number of channels to be transmitted is large, the power varies among the small power signal channels subjected to the compensation control selected by the gate circuit 801, and thus the power varies depending on the relative magnitude of the average power of the channels. By changing the weight coefficient, excellent compensation control can be realized. The weighting factor calculation circuit 805 outputs a small weighting factor if the average power of the own channel is relatively large and a large weighting factor if the average power is relatively small among the channels subjected to the compensation control in a value between 0 and 1. . The multiplication circuit 806 multiplies the weight coefficient by the integration / average circuit output,
This value is used as a control signal for the volume circuit 7 of the own channel.
Output to 10

The invention of the third embodiment is configured as described above, and weights the "compensation of amplitude limitation" for each channel according to the power of each signal channel so that compensation can be performed with high accuracy. Therefore, there is an effect that the error rate of the low power signal channel can be more efficiently prevented from deteriorating.

Embodiment 4 FIG. Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 9 shows the configuration of the transmitting section of the spread spectrum communication apparatus according to Embodiment 4 of the present invention. In FIG. 9, since the configuration and operation other than the control signal generation circuit 908 and the reference control timing circuit 904 are the same as those of the first embodiment, the control signal generation circuit 908 and the reference control timing circuit 904 will be described below.

FIG. 10 shows a configuration per control channel of control signal generation circuit 908 according to the fourth embodiment of the present invention. Reference numeral 1001 denotes a gate circuit for determining whether or not to perform compensation control on the signal of the channel; 1002, a despreading circuit for despreading the multiplex signal; 1003, an amplitude limit value for detecting an excess amount of the multiplex signal from the amplitude limit value. An excess amount detection circuit, 1004 is an integration / averaging circuit that integrates the excess amount within the reference timing and takes an average value, and 1005 is a detection number counter that counts the number of times the multiplex signal exceeds the amplitude limit value within the reference timing.

Next, the detailed operation of the control signal generation circuit will be described. The multiplexed signal output from the control multiplexing circuit 907 is input to the gate circuit 1001. In this circuit, the multiplex signal is cut off or passed by the enable signal from each channel average power control circuit 905, and it is determined whether or not to perform compensation control on the own channel. The multiplexed signal that has passed through the gate circuit 1001 is despread by the despreading circuit 1002 at each reference timing by a spreading code that spreads data of its own channel at the time of transmission by the spreading modulation circuit 902. By this operation, the multiplexed signal is inverted when the spreading code is “0”, and is converted into a non-inverted waveform when the spreading code is “1”.

The amplitude limit value excess amount detection circuit 1003 compares the despread waveform with the amplitude limit value within the reference timing,
If the despread waveform exceeds the amplitude limit value, the excess amount is detected. The excess amount is obtained as a positive or negative value because it is despread in the despreading circuit 1002, and a value of 0 is output when the despread signal is below the amplitude limit value because there is no excess amount. . The integration and averaging circuit 1004 integrates the obtained excess amount within the reference timing and averages it over the time of the reference timing.

The number-of-detections counter 1005 counts the number of times the despread signal exceeds the amplitude limit value within the reference timing, and outputs the same to the reference control timing circuit 904 as a timing generation control signal.

When the number of multiplexes is small and the total transmission power itself is low at the time of transmission power control, the dynamic range of the multiplexed signal is relatively lower than the dynamic range of transmission power amplifier 916. The number of times exceeding the amplitude limit value set by the amplitude limit value setting circuit 906 decreases within the reference timing. The reference control timing circuit 904 performs processing such as extending the reference timing temporally if the number of detections is small according to the value of the timing generation control signal, or generating the reference timing so as to perform intermittent compensation control. By performing the above control, the processing amount of the circuit can be reduced and the power consumption can be suppressed while maintaining the accuracy of the amplitude limit compensation control.

The invention of the fourth embodiment is configured as described above, and performs "compensation for amplitude limitation" for each channel according to the power of each signal channel. There is an effect that the deterioration of the error rate can be prevented. In addition, since "compensation for amplitude limitation" is temporally controlled, the power consumption of the circuit can be reduced.

[0064]

As described above, according to the present invention, even when the transmission power amplifier having a low dynamic range is used and the amplitude of a multiplexed signal is limited, the "amplitude limitation" of each channel is performed in accordance with the power of each channel. Is performed, so that there is an effect that the error rate of the low power channel can be prevented from deteriorating.

Instead of limiting the amplitude of the multiplexed signal by the non-linear amplitude limiting circuit, the volume circuit performs the "amplitude limitation" and "compensation for the amplitude limitation" of each channel in accordance with the power of each channel. Therefore, it is possible to prevent the error rate of the low power channel from deteriorating, and to eliminate the need for a nonlinear amplitude limiting circuit, thereby simplifying the configuration.

When a relatively large number of low-power signal channels are included in the multiplexed signal, the accuracy of amplitude compensation is weighted by weighting "amplitude limit compensation" for each channel according to the power of each channel. I tried to compensate well,
There is an effect that the deterioration of the error rate of the small power channel can be prevented more efficiently.

When the number of multiplexes is small and the frequency of performing the amplitude limitation is low, the "compensation of the amplitude limitation" is temporally controlled, so that the power consumption of the circuit can be reduced. effective.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transmission section of a spread spectrum communication apparatus according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory diagram showing an influence on a small power channel due to amplitude limitation by a conventional device.

FIG. 3 is an explanatory diagram showing a process of compensating an influence on a small power channel due to the amplitude limitation according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a control signal generation circuit according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a transmitting section of a spread spectrum communication apparatus according to Embodiment 2 of the present invention.

FIG. 6 is a block diagram showing a configuration of a control signal generation circuit according to a second embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a transmitting section of a spread spectrum communication apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a block diagram showing a configuration of a control signal generation circuit according to a third embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a transmitting section of a spread spectrum communication apparatus according to Embodiment 4 of the present invention.

FIG. 10 is a block diagram showing a configuration of a control signal generation circuit according to a fourth embodiment of the present invention.

FIG. 11 is a block diagram illustrating a configuration of a transmission unit of a conventional spread spectrum communication apparatus.

[Explanation of symbols]

101, 501, 701, 901 frame assembling circuit, 102, 502, 702, 902 spreading modulation circuit,
103, 503, 703, 903 Multilevel circuit, 10
4, 504, 704, 904 Reference control timing circuit, 105, 505, 705, 905 Each channel average power control circuit, 106, 506, 706, 906 Amplitude limit value setting circuit, 107, 507, 707, 907 Control multiplexing circuit , 108, 508, 708, 908 control signal generation circuit, 109, 509, 709, 909 delay circuit, 110, 510, 710, 910 volume circuit, 111, 511, 711, 911 transmission multiplexing circuit, 112, 712, 912 Non-linear amplitude limiting circuit, 1
13, 512, 713, 913 D / A conversion circuit, 11
4, 514, 714, 914 carrier generation circuit, 11
5, 513, 715, 915 Mixer, 116, 51
5, 716, 916 Transmission power amplifier, 117, 51
6, 717, 917 transmitting antennas, 401, 601,
801, 1001 gate circuit, 402, 602, 80
2, 1002 despreading circuit, 403, 603, 803,
1003 Amplitude limit value excess amount detection circuit, 404, 60
5, 804, 1004 integrating / averaging circuit, 604 dividing circuit, 606 superimposing circuit, 607 delay circuit, 8
05 weight coefficient calculation circuit, 806 multiplication circuit, 1005
Detection count counter. Reference number = 123456-JP-01
(18/1) ￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣￣
￣￣￣￣￣￣￣￣￣￣￣

Claims (4)

[Claims] 1. A multiplexed signal whose amplitude is limited to a predetermined amplitude limit setting value is generated from transmission signals of a plurality of channels which are spread spectrum by different spreading codes for each channel,
In a spread spectrum communication apparatus that transmits the multiplexed signal after power amplification, a control signal generation circuit that generates a control signal for controlling the amplitude of the transmission signal of each channel, and the amplitude of the transmission signal of each channel based on the control signal A plurality of volume circuits variably controlled, and multiplexing the transmission signals of the respective channels variably controlled,
A transmission multiplexing circuit for generating a multiplexed signal, and a non-linear amplitude limiting circuit for limiting the amplitude of a portion of the multiplexed signal exceeding an amplitude limit set value to be equal to or less than the set value, wherein the control signal generation circuit includes: From the average power information and the amplitude limit setting value of the transmission signal of each channel, a control signal for compensating the power fluctuation amount of the transmission signal of each channel due to the amplitude limitation of the multiplexed signal, the volume circuit,
A spread-spectrum communication apparatus, wherein variable control is performed based on the control signal to compensate for the amplitude of a transmission signal of each channel. 2. A multiplexed signal whose amplitude is limited to a predetermined amplitude limit setting value is generated from transmission signals of a plurality of channels that are spread spectrum by different spreading codes for each channel,
In a spread spectrum communication apparatus that transmits the multiplexed signal after power amplification, a control signal generation circuit that generates a control signal for controlling the amplitude of the transmission signal of each channel, and the amplitude of the transmission signal of each channel based on the control signal A plurality of volume circuits variably controlled, and multiplexing the transmission signals of the respective channels variably controlled,
A transmission multiplexing circuit that generates a multiplexed signal, wherein the control signal generation circuit uses the average power information and the amplitude limit setting value of the transmission signal of each channel to determine the amplitude of the multiplexed signal. A control signal for compensating for the power fluctuation amount of the transmission signal and for limiting the amplitude of the transmission signal of each channel so that the amplitude of a portion exceeding the amplitude limit setting value in the multiplexed signal can be amplitude limited to the setting value or less. A spread-spectrum communication apparatus, wherein the volume circuit variably controls so as to compensate and limit the amplitude of a transmission signal of each channel based on the control signal. 3. The compensation of the amplitude of the transmission signal of each channel is as follows:
The spread spectrum communication apparatus according to claim 1, wherein weighting is performed according to an average power of a transmission signal of each channel. 4. Compensation of the amplitude of the transmission signal of each channel is as follows:
The spread spectrum communication apparatus according to claim 1, wherein the multiplexed signal is temporally controlled in accordance with a frequency exceeding an amplitude limit setting value.