JP2752963B2 - CDMA multiplex transmission equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CDMA (code division multiple access) type multiplex transmission apparatus, and more particularly to a CDMA type multiplex transmission apparatus which handles multiple channels used in a mobile communication base station using radio.

[0002]

2. Description of the Related Art A CDMA multiplex transmission apparatus of this kind includes:
Each channel is assigned a spreading code that has a different autocorrelation and is generated at an extremely high rate compared to the transmission rate of the transmission data, and each channel is directly multiplied by the transmission data and the spreading code and modulated. The transmission data is spread over a wide frequency band on the frequency axis, and a plurality of spread channels are multiplexed in the same frequency band. Because of its characteristics of high confidentiality and high resistance to interference and noise in the transmission path due to its modulation method, it is used for mobile communication base stations and the like.

Conventionally, this type of CDMA multiplex transmission apparatus has a plurality of channel sections for modulating transmission data with a spreading code for each channel and spreading the data over a wide band, and converting each spread data signal into an amplitude data signal. A plurality of power control units, a multiplexing unit for adding and multiplexing the amplitude data signals, a D / A converter for converting the multiplexed data signals into analog signals, and a modulating the analog multiplexed signals into a radio frequency band. And a wireless unit that amplifies power and wirelessly transmits the amplified signal.

[0004]

As described above, in the prior art, a digital signal obtained by spreading and multiplexing a transmission data signal of each channel is converted into an analog signal by a D / A converter, and then converted by a radio unit. Since modulation and power amplification are performed, the transmission power fluctuates due to factors such as the nonlinearity of the D / A converter and the temperature fluctuation of the power amplification degree in the radio section of the analog signal, and the transmission power for each channel varies. Occurs. Normally, if the variation is small, there is no problem.However, if the variation factor is increased and the variation is increased, there is a problem that a mobile radio device on a channel with a low power cannot receive signals due to interference of a channel with a high power on the receiving side. is there.

In the direction from the mobile radio to the base station receiving direction, there is the same problem as described above due to the distance difference. Therefore, conventionally, the transmission power on each mobile radio side is controlled to reduce the reception power on the base station receiving side. There is a technology to align channels. However, in the base station transmission direction, there is no function to control the transmission power for each channel, so that the above-described problem occurs.

[0006]

SUMMARY OF THE INVENTION A CDMA multiplex transmission apparatus according to the present invention modulates transmission data of each channel with a different spreading code for each channel, spreads the data over a wide band, and converts this spread data signal into an amplitude data signal. In the CDMA multiplex transmission apparatus which converts the multiplexed data signal into an analog signal, modulates the multiplexed data signal into a radio frequency band, amplifies the power, and transmits the amplified signal with a radio, the spread code of each channel is transmitted to the radio. A switching means for sequentially switching to a power control code for transmission power measurement for each channel for a short time, and a part of the transmission power which is branched and converted into a predetermined frequency band and then synchronized with the switching means. Detecting means for despreading the power control code of each channel with a multiplexed code and detecting transmission power information for each channel, and corresponding to the transmission power information Wherein the transmission power of each channel change modifying the amplitude data channels and a power control means for controlling so as to be aligned to a predetermined value that.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment according to the present invention. Although the present embodiment shows the case where the number of channels is three, the number of channels is usually many in many cases.

The channel section 1 is composed of a spreading code generator 12, a switch 13, and a multiplier 11. The spreading code generator 12 generates an orthogonal code (M-sequence code) for realizing code division in synchronization with a clock 106 output from the timing controller 9 described later. The spreading code output from the spreading code generator 12 is sent to one end of the switch 13. The power control code 101 output from the power control code generator 10 is input to the other end of the switch 13, and the switch 13 uses the clock 103 output from the timing controller 9 to transmit the spread code and the power control code 1.
01 is selected and output. The multiplier 11 multiplies the spreading code or the power control code 101 output from the switch 13 by the transmission data 105 input from the outside, spread modulates the transmission data 105, and outputs the result.

The power control unit 2 receives the spread transmission data 108 output from the channel unit 1 as a first input, and the power control signal 104 output from the despreading unit 8 described later as a second input. Select and modify and output.

The multiplexing unit 3 performs multiplexing by adding the amplitude data of each channel output from the power control unit 2 and outputs the multiplexed amplitude data. The D / A converter 4 is a multiplexer 3
The multiplexed amplitude data output from the multiplexor is input and the multiplexed amplitude data is converted into an analog quantity and output.

The radio unit 5 modulates and amplifies the power of the analog signal output from the D / A converter 4 and outputs the amplified signal to the distributor 6.
The distributor 6 distributes the output of the radio unit 5 to the transmitter output and the power control output. The output for power control is input to the frequency converter 7. The frequency conversion unit 7 performs frequency conversion, converts the frequency into a predetermined frequency band, and outputs the frequency band to the despreading unit 8.

The despreading unit 8 converts the frequency-converted signal into a first signal.
And the power control code 102 generated by the power control code generator 10 is despread as a second input to detect the instantaneous power of each channel. The despreading is performed in the order of channels according to the clock 107 input from the timing control unit 9, and as a result, power control signals separated for each channel are output to each power control unit 2.

In the power control code generator, the power control code 101, which is extremely short compared to the code length of the spread code,
And a power control code 102 obtained by multiplexing them. The timing control section 9 divides the frequency of the basic clock by a counter, and generates a clock for adjusting the timing of the channel section 1 and the spreading section 8.

Next, the operation will be described. In the CDAM system, multiplexing is realized by assigning a spreading code having excellent autocorrelation characteristics to each channel. In the present invention, the transmission power of each channel is despread by inserting a power control code 101 that has a partial orthogonality of the spreading code assigned to each channel but has a code length that is extremely short compared to the addition code, and despreads. Measured and controlled.

As shown in FIG. 1, each channel unit 1 outputs the spread transmission data to a power control unit 2 corresponding to each channel. Here, the spreading code generator 12 repeatedly generates a pseudo noise code. The output time of the spread code output from the spread code generator 12 is shifted for each channel. Here, an M-sequence code of 2 15 is used as the pseudo noise code. The power control code 101 inserted into the spreading code uses a 2-4 power M-sequence code. However, the power control code 101 has an extremely short code length as compared with the spread code so as not to lower the discrimination ability of each channel, which is the original purpose.

FIG. 2 shows the output signal 108 of the channel unit 1, that is, the format of the spread transmission data and the power control codes 102 and 103. The power control code 101 has a code length of 327687 bits and a power control code 101 of 15 bits.
The power control code 101 is approximately 2200 of the spreading code.
A code length of 1/0 is selected. .. Of the channel section output signal 108 indicate that the same code is repeated from 0. X indicates a power control code 101.

As described above, the spreading code used in each channel section is repeated at different timings. Also, the inserted power control code 101 is arranged so as not to overlap in each channel. This is to identify which power control code 101 of each channel after multiplexing.

The insertion of the power control code 101 into the spreading code is performed by operating the switch 13 at the timing of the clock 103. The power control code 102 used in the despreading unit 8 is the power control code 101
Are arranged on the time axis.

The output signal 108 of each channel unit 1 is input to the power control unit 2. The power control unit 2 has a function of converting the output signal 108 of the channel unit into amplitude data, and accumulates instantaneous transmission power of the channel from the input power control signal 104 to calculate an average power. And a function of further correcting the amplitude data.

FIG. 3 is a block diagram showing an internal circuit of the power control unit 2. Output signal 10 input from channel 1
A / D converter 22 for converting analog information of the instantaneous transmission power of the channel into digital data by a power control signal 104 output from the despreading unit 8; D conversion unit 22
Latch 23 for holding the output of the clock for timing synchronization
A RAM 24 for storing analog information of the instantaneous transmission power quantized for accumulation, and the transmission data after spreading and D
A ROM 25 storing amplitude data as a basis for analog conversion by the A / A conversion unit 4, a latch 21 and an RA
M24, which is connected to the ROM 25, accumulates the quantized analog information held in the RAM 24, obtains an average value, and selects basic amplitude data to be output to the D / A converter 9 stored in the ROM 25, It comprises a DSP 26 that limits the data variable range.

The power control signal 104 indicates the instantaneous transmission power of the channel that is actually transmitting in analog voltage.
The average transmission power is calculated by accumulating the analog voltage for a specified time, compared with the power to be transmitted, and power control is performed so that the difference becomes small.

The output of the power control unit 2 is input to the multiplexing unit 3, where the amplitude data of each channel is added and multiplexed. FIG. 5 is a block diagram showing an internal circuit of the multiplexing unit 3. Each output of each power control unit 2 is composed of a latch 31 for holding for timing synchronization, and an adder 32 for simply adding the latched data. The amplitude data of each channel is multiplexed and D / A converted. It is output to the unit 4.

The multiplexed amplitude data output from the multiplexing unit 3 is converted into an analog amount by the D / A conversion unit 4, and is transmitted after being modulated and amplified by the radio unit 5. The output of the radio unit 5 is distributed to a transmitter output and a power control output by a distributor 6, and the power control output is input to a frequency conversion unit 7, converted to a designated frequency band, and output to a despreading unit 8. .

FIG. 5 is a block diagram showing the internal circuit of the inverse expansion unit 7. The frequency-converted signal is despread by multiplying the power control code 102 according to the clock 107. Since despreading is performed by the power control code 103, its correlation output, that is, the power control signal 104 is
The signals are separated and output in the order of the channel into which 1 is inserted.

That is, the output of the frequency conversion unit is used as a first input, and a power control code 102 in which power control codes 101a to 101c having a code length of 15 bits are continuously arranged on a time axis is used as a second input to perform multiplication. A multiplier 81 for performing despreading,
The selector 30 is configured to select and output the power control signal 104 for each channel from the output of the multiplier 81 by the clock 107.

FIG. 7 is a block diagram showing an internal circuit of the timing controller 9. A clock 91 for generating each reference clock, a BCD counter 92 for counting the clock to generate a fixed pattern, and a shift register 9 for delaying the pattern for timing synchronization
3 The outputs of the BCD counter 92 become clocks 103a to 103c and are output to each channel unit while being shifted by one count. As a result, the power control code 101 is inserted into each channel without being switched at the same time by the switch 12 inside the channel unit 1 and always shifted by one bit. Clock 107 output to despreading unit 7
Is output through the shift register 93 taking into account the loop delay. As a result, timing synchronization is established.

[0027]

As described above, the CDMA multiplex transmission apparatus of the present invention inserts the power control code for power measurement into the spread code of each channel, thereby reducing the transmission power of each channel at the output of the radio unit. Measurement is performed and the transmission power of each channel is controlled so as to be equal to a predetermined value. It has the effect of receiving.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing formats of transmission data and a power control code after spreading in FIG. 1;

FIG. 3 is a block diagram showing an internal circuit of a power control unit 2 in FIG.

FIG. 4 is a block diagram showing an internal circuit of a multiplexing unit 3 in FIG.

FIG. 5 is a block diagram showing an internal circuit of a despreading unit 8 in FIG.

FIG. 6 is a block diagram showing an internal circuit of a timing control section 9 in FIG.

[Explanation of symbols]

 1a to c channel unit 2a to c power control unit 3 multiplexing unit 4 D / A conversion unit 5 radio unit 6 distributor 7 frequency conversion unit 8 despreading unit 9 timing control unit 10 power control code generation unit 11 multiplier 12 spreading code Generator 13 Switch 21 Latch 22 A / D Converter 23 Latch 24 RAM 25 ROM 26 DSP (Digital Signal Processor) 31a-c Latch 32 Adder 81 Multiplier 91 Clock 92 BCD Counter 93 Shift Register

Claims (5)

(57) [Claims] 1. The transmission data of each channel is modulated with a spreading code different for each channel and spread over a wide band, and the spread data signal is converted into an amplitude data signal and then multiplexed, and the multiplexed data signal is converted into an analog signal. In a CDMA multiplex transmission apparatus that converts the spread code into a radio frequency band, amplifies the power, and transmits the radio signal, the spread code of each channel is sequentially shortened to a power control code for measuring the transmission power in the radio device for each channel. Switching means for switching only for a time; and a part obtained by multiplexing the power control code of each channel in synchronization with the switching means after branching a part of the transmission power and converting the branch transmission power to a predetermined frequency band. Detecting means for spreading and detecting transmission power information for each channel, and changing and correcting the amplitude data of the corresponding channel by the transmission power information, A power control unit for controlling the transmission power to be equal to a predetermined value.
MA multiplex transmission equipment. 2. A multiplier for multiplying the input transmission data by a spreading code to spread the transmission data over a wide band on a frequency axis, and generating the spreading code having a different pattern depending on a channel from a first clock. A spreading code generator and a switch for switching the spreading code supplied to the multiplier to a power control code for measuring transmission power for a time period of a clock pulse by a second clock signal having a different timing depending on a channel. Multiple channel sections to
A plurality of power control units corresponding to each channel unit, which converts the output signal of each of the channel units into amplitude data and simultaneously changes and corrects the amplitude data with a power control signal, and adds and multiplexes the output signals of each of the power control units. And a multiplexing unit for converting the multiplexed transmission data into an analog signal.
/ A conversion unit, a radio unit that modulates an output signal of the D / A conversion unit into a radio frequency band and amplifies power, a splitter that splits a transmission output signal of the radio unit, and a branch output signal of the splitter And a frequency conversion unit that converts the output signal of the frequency conversion unit into a predetermined frequency band, and extracts a correlation output by despreading an output signal of the frequency conversion unit with a multiplexed power control code obtained by multiplexing the power control code of each channel. A despreading unit that separates each channel by a third clock and outputs the power control signal as a power control signal; A power control code generation unit for generating the power control code and the multiplexed power control code obtained by multiplexing the power control code in a time-division manner, and counting the first clock of the basic clock and the first clock; A timing control unit for generating the first clock, which is a parallel signal whose generation period is sufficiently long and is shifted by one count for each channel, and the third clock obtained by converting the first clock into a serial signal; And a CDMA multiplex transmission apparatus. 3. The spreading code generator of each channel section extracts a code generator that repeatedly generates the same code in synchronization with the first clock, and extracts the generated code at a timing shifted for each channel. 3. The CDMA multiplex transmission apparatus according to claim 2, further comprising an output circuit for outputting the spread code as the spread code. 4. The despreading unit multiplies an output signal of the frequency conversion unit by the multiplexed power control code to despread, and outputs a correlation output of each continuous channel obtained as a result of the multiplication. 3. The CDMA multiplex transmission apparatus according to claim 2, further comprising: a selector that synchronizes with the third clock, separates the signals for each channel, and outputs the power control signal. 5. A power control unit comprising: a first latch circuit for holding spread transmission data input from the channel unit for timing synchronization; and an analog information of an instantaneous transmission power of the power control signal. An A / D converter for converting the data into digital data, a second latch circuit for holding the output of the A / D converter for timing synchronization, a RAM for holding the latch output for accumulation, A ROM storing basic amplitude data for analog-to-digital conversion by the D / A converter of the transmission data, and transmitting the spread transmission data latched based on information stored in the ROM and the RAM. 3. The CDMA multiplex transmission apparatus according to claim 2, further comprising a digital signal processor that converts the data into data.