JPH09270733A - Spread spectrum communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption of a transmitter. SOLUTION: After being incorporated in a transmission frame format accompanied by the respective kinds of control information or the like in frame assembly circuits 101, respective lines are spread by spreading codes allocated to the respective lines in spreading circuits 102. The output of the spreading circuits 102 for the respective lines is gathered in one system in an addition circuit 103, band-limited in a band limiting filter 104, converted into analog signals in a DA conversion circuit 105, frequency-converted into the signals of a carrying band in a mixer 106, amplified in a power amplifier 108 and transmitted from an antenna 109. In the band limiting filter 104, by receiving the information of the number of multiplexed lines at present from a controller 110 and performing band limiting by the filter of the number of required sufficient taps corresponding to the number of multiplexed lines, the power consumption of the band limiting filter 104 is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication device used for digital radio communication such as a car phone and a mobile phone.

[0002]

2. Description of the Related Art FIG. 6 shows the structure of a transmitter in a conventional spread spectrum communication device. In FIG. 6, 6
01 is a frame assembling circuit, 602 is a spreading circuit, 603 is a band limiting filter, 604 is a DA converting circuit, 605 is a double balanced mixer, 606 is a carrier wave oscillating circuit, 60
Reference numeral 7 is a power amplifier circuit, and 608 is a transmission antenna. The transmission data is incorporated into a transmission frame format accompanied by various control information and the like in the frame assembling circuit 601, and then multiplied by the spreading code in the spreading circuit 602. The spread transmission data is band-limited by the band-limiting filter 603, converted into an analog signal by the DA conversion circuit 604, then modulated by the mixer 605 by the signal in the carrier band from the carrier oscillation circuit 606, and the power amplification circuit 607. Is amplified by and transmitted from the antenna 608.

[0003]

However, in the above-mentioned conventional transmitter, since the calculation accuracy of the band limiting filter 603 is fixed, there is a case where the number of multiple channels or the number of simultaneous communication users is small and the interference power is small. , When the system load is light and the required accuracy for waveform distortion in the band-limiting filter is relatively low, the band-limiting filter may ensure more calculation accuracy than is necessary, resulting in sufficient reduction in power consumption. I had the problem of not being able to do it.

An object of the present invention is to solve the above conventional problems and to provide an excellent spread spectrum communication device with low power consumption.

[0005]

In order to solve the above problems, the spread spectrum communication apparatus of the present invention determines the calculation accuracy of the band limiting filter in the transmitter according to the interference power.
The power consumption in the transmitter is reduced by adaptively adjusting to the point of the lowest power consumption at which the required communication quality is obtained. That is, when the interference power is large and the quality deterioration due to the waveform distortion is not allowed, the filter with a large number of taps is operated so that the waveform distortion is small and the sharp band limiting characteristic is obtained, and the interference power is small and the quality deterioration due to the waveform distortion is caused. In the case where is allowed to some extent, the power consumption is reduced by using a filter with a smaller number of taps that gives priority to the band limiting characteristic. As a result, an excellent spread spectrum communication device with low power consumption can be realized.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention uses a direct spread method as a transmission method of a digital signal, and has a band limiting filter in a front stage of a transmission power amplifier,
It is characterized in that the calculation accuracy of the band limiting filter is changed according to the magnitude of interference or external noise between code division multiplexed signals. When the interference level is low, waveform distortion can be tolerated. By lowering the calculation accuracy of the band limiting filter within the range, there is an effect that the power consumption of the spread spectrum communication device can be reduced. That is, when the interference level is large and the quality deterioration due to the waveform distortion is not allowed, the filter with a large number of taps is operated so that the waveform distortion is small and the steep band limiting characteristic is obtained, and the interference level is small and the quality due to the waveform distortion is small. When the deterioration is allowed to some extent, the power consumption is reduced by using a filter with a smaller number of taps that gives priority to the band limiting characteristic.

[0007] The invention described in claim 2 of the present invention provides
If the band-limiting filter has a high interference level and cannot cause quality deterioration due to waveform distortion, operate a filter with a large number of taps to obtain a sharp band-limiting characteristic with small waveform distortion, and use a filter with a small interference level. When the quality deterioration due to distortion is allowed to some extent, the filter is characterized by using a filter with a smaller number of taps that prioritizes the band limiting characteristic. It has the effect that it can be set accurately based on the above.

[0008] The invention described in claim 3 of the present invention provides:
The direct spread method is used as the digital signal transmission method,
The base station receiver has a band limiting filter in the preceding stage of the transmission power amplifier, the base station receiver includes means for measuring the interference level for each channel from the received signal, and means for notifying the mobile station of the measured interference level information. The station is provided with means for acquiring the interference level information notified from the base station, and using the acquired interference level information, the calculation accuracy of the band limiting filter of the mobile station transmitter is determined. By performing closed loop control of the calculation accuracy of the band limiting filter, there is an effect that the calculation accuracy can be set accurately.

Further, the invention according to claim 4 of the present invention provides:
The receiver is provided with means for measuring an interference level with respect to a channel being received, and using the measured interference level information, the calculation accuracy of the reception filter of the receiver is changed. When the interference power is small, the calculation accuracy of the reception filter is lowered within a range in which the waveform distortion can be tolerated, so that there is an effect that the power consumption of the spread spectrum communication apparatus can be reduced.

The invention according to claim 5 of the present invention provides:
When the receiver has a high interference level and cannot deteriorate the quality due to waveform distortion, it operates a filter with a large number of taps so that the waveform distortion is small and steep band limiting characteristics are obtained. If the quality deterioration due to the above is allowed to some extent, the filter with a smaller number of taps that prioritizes the band limiting characteristic is used, and the calculation accuracy of the reception filter is based on the interference level information. It has the effect that it can be set accurately.

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows the configuration of a base station transmitter of a mobile phone as a spread spectrum communication apparatus according to a first embodiment of the present invention. In FIG. 1, 101 is a frame assembly circuit, 102 is a diffusion circuit, and 1
Reference numeral 03 is an adder circuit, 104 is a band limiting filter, 105 is a DA conversion circuit, 106 is a double balanced mixer,
Reference numeral 7 is a carrier wave oscillation circuit, 108 is a power amplification circuit, 109 is a transmission antenna, and 110 is a control device.

FIG. 2 shows the structure of the band limiting filter 104. The band limiting filter 104 is a digital transversal filter, and includes a data shift register 201, a multiplier 202, and a tap coefficient register 20.
3, an adder circuit 204, and a switch 205.

The operation of the base station transmitter configured as described above will be described. In FIG. 1, each line is incorporated into a transmission frame format accompanied by various control information and the like by a frame assembling circuit 101, and then spread by a spreading code assigned to the line by a spreading circuit 102. The outputs of the spreading circuit 102 for each line are combined into one system by the adding circuit 103 and sent to the band limiting filter 104. In the band limiting filter 104, the information on the number of currently multiplexed lines is provided to the control device 110.
The bandwidth is limited by a filter having a necessary and sufficient number of taps according to the number of multiplexed lines. The band-limited multiplexed signal is converted into an analog signal by the DA conversion circuit 105, modulated by the mixer 106 with the carrier band modulation signal from the carrier oscillation circuit 107, and then the power amplification circuit 108.
The signal is amplified by and is transmitted from the antenna 109.

Next, the operation of the band limiting filter 104 will be described with reference to FIG. The band limiting filter 104 is
It is a digital transversal filter with a tap number M so that a waveform distortion characteristic that can secure transmission quality in the maximum number of lines assumed can be obtained. When the number of multiplexed lines is large, the switch 205 is closed and the data shift register 201, the multiplier 202, the tap coefficient register 203, and the adder circuit 204 are all used to operate as a filter with a large number of taps and small waveform distortion. . When the number of multiplexed lines is small and the waveform distortion can be tolerated to some extent, the switch 205 provided in the middle of the data shift register 201 is opened and the value of the tap coefficient register 203 is set to a desired band limiting effect with a smaller number of taps. Change the value so that it can be obtained. By setting the value of the tap coefficient register 203 in the subsequent stage from the switch 205 to zero, the number of elements that actually operate can be reduced and power consumption can be reduced. In this case, the waveform distortion increases, but in many mobile phone systems, it is not necessary to realize a transmission quality higher than necessary with respect to the system design value, and low power consumption is prioritized.

In the above first embodiment, the switch 20
By providing 5 at a plurality of positions of the data shift register, it is easy to set the switching of the number of taps more finely than two steps. Further, although the present embodiment is an example of a mobile phone base station, it is necessary to multiplex and use a plurality of spreading codes also in a mobile station when performing high-speed data transmission. The transmitter of the machine also has the same configuration as that of this embodiment.

As described above, according to the first embodiment,
By providing the band limiting filter 104 capable of changing the calculation accuracy in accordance with the magnitude of the interference power in the preceding stage of the transmission power amplifier 108, the number of elements actually operating can be reduced and the power consumption can be reduced. Can be planned.

(Second Embodiment) FIG. 3 shows the configuration of a base station of a mobile phone as a spread spectrum communication apparatus according to a second embodiment of the present invention. In FIG. 3, 3
01 is a frame assembling circuit, 302 is a spreading circuit, 303 is an adding circuit, 304 is a band limiting filter, 305 is a DA converting circuit, 306 is a mixer, 307 is a carrier wave oscillating circuit, 3
08 is a power amplifier circuit, 309 is an antenna duplexer, 310
Is an antenna, 311 is a low noise amplification circuit, 312 is a carrier wave oscillation circuit, 313 is a mixer, 314 is an AD conversion circuit, 3
Reference numeral 15 is a reception filter, 316 is a distribution circuit, 317 is a despreading circuit, 318 is an interference measurement circuit, and 319 is a frame decomposition circuit.

FIG. 4 shows the configuration of the mobile station in this embodiment. In FIG. 4, 401 is a frame assembling circuit, 402 is a spreading circuit, 403 is a band limiting filter, 4
Reference numeral 04 is a DA conversion circuit, 405 is a mixer, 406 is a carrier wave oscillation circuit, 407 is a power amplification circuit, 408 is an antenna duplexer, 409 is an antenna, 410 is a noise amplification circuit, 41
1 is a carrier wave oscillation circuit, 412 is a mixer, 413 is an AD conversion circuit, 414 is a reception filter, 415 is a despreading circuit,
Reference numeral 416 is a frame decomposing circuit.

The operation of the spread spectrum mobile phone configured as described above will be described. First, FIG.
The reception operation in the base station will be described using. The received signal captured by the antenna 310 is amplified by the low noise amplifier 311 from the antenna duplexer 309, and then the mixer 3
At 13, the signal from the carrier wave oscillating circuit 312 is converted into a baseband signal, at the AD conversion circuit 314 it is converted to a digital signal, at the reception filter 315 the waveform is shaped, and at the distribution circuit 316, a despreading circuit 317 for each line.
And to the interference measurement circuit 318. Despreading circuit 3
The signal input to 17 is demodulated for each line and decomposed by the frame decomposition circuit 319 into received data and various control information. Separately from the data demodulation, the interference measurement circuit 318
The interference level for each line is measured at the line, and the measured interference level information is used for the frame assembling circuit 301 for each line.
Is added to the transmission data and notified to the mobile station.

Next, the transmission operation in the base station will be described. The transmission data of one line is the frame assembly circuit 3
In 01, it is incorporated into a transmission frame format in which interference level information measured by the interference measuring circuit 318 is added in addition to various control information, and then spread by the spreading code assigned to the line in the spreading circuit 302. . The outputs of the spreading circuit 302 for each line are combined into one system by the adding circuit 303 and sent to the band limiting filter 304. The band-limited multiplexed signal is converted into an analog signal by the DA conversion circuit 305, and then the carrier wave oscillation circuit 3 is mixed by the mixer 306.
The signal is modulated by the carrier band modulation signal from 07, amplified by the power amplification circuit 308, and transmitted from the antenna 310 through the antenna duplexer 309.

Next, the receiving operation in the mobile station will be described. In FIG. 4, the received signal captured by the antenna 409 is transmitted from the antenna duplexer 408 to the low noise amplifier 41.
Amplified by 0, converted into a baseband signal by the signal from the carrier oscillation circuit 411 by the mixer 412, and AD
The conversion circuit 413 converts the signal into a digital signal, the reception filter 414 performs waveform shaping, the despreading circuit 415 demodulates, and the frame decomposing circuit 416 transmits data and various control information and interference level information measured by the base station receiver. Is decomposed into.

Next, the transmission operation in the mobile station will be described. The transmission data is incorporated into a transmission frame format accompanied by various control information and the like by the frame assembling circuit 401, and then spread by the spreading code assigned to the mobile station by the spreading circuit 402, and then the band limiting filter 40.
Sent to 3. The band-limited multiplexed signal is converted into an analog signal by the DA conversion circuit 404, and then the mixer 425.
Is modulated by the carrier band modulation signal from the carrier oscillation circuit 406, amplified by the power amplification circuit 407, and transmitted from the antenna 409 through the antenna duplexer 408.
Here, the control of the calculation accuracy in the band limiting filter 403 is performed based on the interference level information notified from the base station.

As described above, according to the second embodiment,
The base station uses an interference measurement circuit 3 for measuring the interference level.
18 and a frame assembling circuit 3 for adding the measured interference level information to the transmission data to notify the mobile station.
01, the mobile station uses the frame decomposition circuit 416 for acquiring the interference level information notified from the base station, and the acquired interference level information, and the calculation accuracy of the band limiting filter 403 of the mobile station transmitter. Therefore, the calculation accuracy of the band limiting filter 403 can be closed-loop controlled, and the calculation accuracy of the band limiting filter 403 in the mobile station transmitter can be correctly set.

(Third Embodiment) FIG. 5 shows the configuration of a mobile station receiver of a mobile phone as a spread spectrum communication apparatus according to a third embodiment of the present invention. In FIG. 5, 501 is an antenna, 502 is a low noise amplifier circuit, 50
3 is a mixer, 504 is a carrier wave oscillation circuit, 505 is an AD conversion circuit, 506 is a reception filter, 507 is a despreading circuit,
Reference numeral 508 is a frame decomposing circuit, and 509 is an interference measuring circuit. The configuration of the reception filter 506 is similar to that shown in FIG.

The operation of the mobile station receiver configured as described above will be described. In FIG. 5, the antenna 5
The received signal captured by 01 is amplified by the low noise amplifier 502, converted into a baseband signal by the signal from the carrier wave oscillation circuit 504 by the mixer 503, converted into a digital signal by the AD conversion circuit 505, and received by the reception filter. The waveform is shaped in 506 and input to the despreading circuit 507 and the interference measuring circuit 509. The signal input to the despreading circuit 507 is demodulated by performing an operation reverse to the spreading, and is decomposed by the frame decomposing circuit 508 into received data and various control information. Separately from the data demodulation, the interference measurement circuit 509
At, the interference level for the channel being received is measured, and the calculation accuracy of the reception filter 506 is changed based on the measured interference level information. That is, when the interference level is large, the reception filter is operated as a filter with a large number of taps and a small amount of waveform distortion, and when the interference level is small and a certain amount of waveform distortion is tolerable, the value of the tap coefficient register is set to a smaller number of taps. The value is changed so that the required band limiting effect can be obtained by a number, and only some taps are operated to reduce the power consumption in the reception filter.

As described above, according to the third embodiment,
By providing the reception filter 506 capable of changing the calculation accuracy in accordance with the magnitude of the interference level, it is possible to reduce the number of elements that actually operate and reduce the power consumption of the mobile station receiver. . Note that this embodiment is an example of a mobile phone mobile station, but the receiving unit of the base station can be implemented in the same manner as this embodiment.

[0028]

As described above, according to the present invention, the direct spread method is used as the transmission method of the digital signal, the band limiting filter is provided in the preceding stage of the transmission power amplifier, and the interference or the external noise between the code division multiplexed signals. It is characterized in that the calculation accuracy of the band-limiting filter is changed according to the size of the band-limiting filter. When the interference level is low, the calculation accuracy of the band-limiting filter should be lowered within a range where waveform distortion is acceptable. Thus, there is an effect that the power consumption of the spread spectrum communication device can be reduced.

Further, according to the present invention, a direct spread method is used as a transmission method of a digital signal, a band limiting filter is provided in the preceding stage of a transmission power amplifier, and a base station receiver measures an interference level from a received signal to each channel. And comprising means for notifying the mobile station of the measured interference level information, the mobile station comprising means for acquiring the interference level information notified from the base station, utilizing the acquired interference level information, It is characterized in that the calculation accuracy of the band-limiting filter of the mobile station transmitter is determined. By performing closed-loop control of the calculation accuracy of the band-limiting filter, it is possible to set the calculation accuracy accurately. Have.

In the present invention, the receiver includes means for measuring the interference level for the channel being received, and the measured accuracy of the interference level is used to change the calculation accuracy of the reception filter of the receiver. When the interference power is low, it is possible to reduce the power consumption of the spread spectrum communication device by lowering the calculation accuracy of the reception filter within a range in which the waveform distortion can be tolerated. Have an effect.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a mobile phone base station device according to a first embodiment of the present invention.

FIG. 2 is a schematic block diagram of a band limiting filter according to the first embodiment of the present invention.

FIG. 3 is a schematic block diagram of a mobile phone base station device according to a second embodiment of the present invention.

FIG. 4 is a schematic block diagram of a mobile phone mobile station apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a schematic block diagram of a mobile phone mobile station apparatus according to Embodiment 3 of the present invention.

FIG. 6 is a schematic block diagram of a conventional mobile phone mobile station device.

[Explanation of symbols]

 101 Frame Assembly Circuit 102 Spreading Circuit 103 Addition Circuit 104 Band Limiting Filter 105 DA Conversion Circuit 106 Double Balanced Mixer 107 Carrier Wave Oscillation Circuit 108 Power Amplification Circuit 109 Transmission Antenna 110 Control Device 201 Data Shift Register 202 Multiplier 203 Tap Coefficient Register 204 Pipeline Adder 205 Switch 301 Frame Assembly Circuit 302 Spreading Circuit 303 Addition Circuit 304 Band Limiting Filter 305 DA Conversion Circuit 306 Mixer 307 Carrier Oscillation Circuit 308 Power Amplifier Circuit 309 Antenna Duplexer 310 Antenna 311 Low Noise Amplifier Circuit 312 Carrier Oscillator Circuit 313 mixer 314 AD conversion circuit 315 reception filter 316 distribution circuit 317 despreading circuit 318 interference measurement circuit 319 frame decomposition times Path 401 Frame assembly circuit 402 Spreading circuit 403 Band limiting filter 404 DA conversion circuit 405 Mixer 406 Carrier wave oscillation circuit 407 Power amplification circuit 408 Antenna duplexer 409 Antenna 410 Low noise amplification circuit 411 Carrier wave oscillation circuit 412 Mixer 413 AD conversion circuit 414 Reception filter 415 despreading circuit 416 frame decomposing circuit 501 antenna 502 low noise amplifying circuit 503 mixer 504 carrier wave oscillating circuit 505 AD converting circuit 506 receiving filter 507 despreading circuit 508 frame decomposing circuit 509 interference measuring circuit 601 frame assembling circuit 602 spreading circuit 603 band limiting Filter 604 DA conversion circuit 605 Double balanced mixer 606 Carrier wave oscillation circuit 607 Power amplification circuit 608 Transmission antenna

Claims (5)

[Claims] 1. A direct spread method is used as a digital signal transmission method, and a band limiting filter is provided in the preceding stage of a transmission power amplifier, and the band limiting filter is provided according to the magnitude of interference between code-division multiplexed signals or external noise. Spread spectrum communication device characterized by changing the calculation accuracy of. 2. When the band-limiting filter has a large interference level and is not allowed to deteriorate in quality due to waveform distortion, the filter having a large number of taps is operated so as to obtain a sharp band-limiting characteristic with small waveform distortion, The spread spectrum communication apparatus according to claim 1, wherein a filter having a smaller number of taps, which prioritizes the band limiting characteristic, is used when the interference level is small and the quality deterioration due to the waveform distortion is allowed. . 3. A direct-spreading method is used as a digital signal transmission method, a band limiting filter is provided in front of a transmission power amplifier, and a base station receiver measures the interference level from the received signal to each channel. Means for notifying the mobile station of the generated interference level information, the mobile station
A spread spectrum communication device comprising means for acquiring interference level information notified from a base station, and using the acquired interference level information, determining the calculation accuracy of a band limiting filter of a mobile station transmitter. . 4. The receiver comprises means for measuring an interference level for a channel being received, and the measured interference level information is used to change the calculation accuracy of a reception filter of the receiver. Spread spectrum communication device. 5. When the receiver has a large interference level and is not allowed to deteriorate quality due to waveform distortion, the receiver operates a filter with a large number of taps so as to obtain a sharp band limiting characteristic with small waveform distortion, and interference is caused. 5. The spread spectrum communication apparatus according to claim 4, wherein a filter having a smaller number of taps, which gives priority to band limiting characteristics, is used when the level is small and the quality deterioration due to waveform distortion is allowed.