JP2912292B2 - Modulator for code division multiple access communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modulation apparatus for a CDMA (hereinafter referred to as "code division multiple access") communication system in which signals spread and modulated by spread spectrum are multiplexed in the same frequency band for communication.

[0002]

2. Description of the Related Art In a CDMA communication system, transmission data for each channel is spread-modulated by a spreading code for each channel in a spread signal generator , and the spread signals of a large number of spread-modulated channels are added by an adder. Multiplex,
Transmission is performed after performing radio modulation at the carrier frequency. On the receiving side, on the other hand, the receiving side receives the transmission signal, demodulates the signal into a baseband signal, and performs correlation detection using an orthogonal code sequence similarly to the transmitting side.

[0005] In the modulation apparatus in the CDMA communication system as described above, FIG.
A plurality of diffusion units 10-1, 10-2, 1 as shown in FIG.
0-3,..., 10-N-1, 10-N and an adder unit 12 as one adder are mounted, and added to the spreading units 10-1,. The unit 12 is connected to each other by using one wiring 13-1,..., 13-N.

That is, the output terminal of the first diffusion unit 10-1 is connected to the first signal line 13-1 of the backplane 11.
Is connected to the first terminal of the addition unit 12 by the
The output terminal of the diffusion unit 10-2 is the backplane 1
One of the second signal lines 13-2 is connected to the second terminal of the addition unit 12, and the output terminal of the Nth diffusion unit 10-N is connected to the addition unit by the Nth signal line 13-N of the backplane 11. 12th Nth terminal.
Then, the plurality of diffusion units 10 are added by the addition unit 12.
Signals of a large number of channels spread by -1 to 10-N are added. When the output signals from the diffusion units 10-1 to 10-N are serial, one signal line is used.
The adder unit 12 has one input terminal, but if the output signals from the spreading units 10-1 to 10-N are separate I and Q or parallel, the number of signal lines increases accordingly. .

[0005]

However, in such a conventional modulator of the CDMA communication system, the output terminals of the spreading units 10-1 to 10-N and the adding unit 12 are used.
Are connected in a one-to-one relationship, so that as the number of channels increases, the number of signal lines 13-1 to 13-N between the plurality of spreading units 10-1 to 10-N and the adding unit 12 increases. ,
As a result, there has been a problem that wiring work of these signal lines becomes difficult.

The present invention solves the above-described problem. By cascading a plurality of diffusion units, the number of signal lines on the backplane can be reduced, and the work of wiring each signal line can be simplified. An object is to obtain a CDMA modulator.

[0007]

To achieve the above object,
According to a first aspect of the present invention, there is provided a modulation apparatus for a code division multiple access communication system, wherein an adder adds and multiplexes spread signals of a plurality of channels spread and modulated by a plurality of spreading units with a spreading code. In a modulator of a multiple access communication system, output terminals of the plurality of spreading units are provided.
Are cascaded to the input terminals of other diffusion units, respectively.
And the diffusion units are each connected to the input terminal.
Spread signal generated internally in operation data input from
Is added by a built-in adder, and the addition result is output to the output terminal.
This is output from the child as new operation data .

[0008] In the modulation apparatus for a code division multiple access communication system according to the second aspect of the present invention, each of the spreading units is cascade-connected to a next spreading unit and a next spreading unit adjacent thereto. It was made.

Further, a modulation apparatus for a code division multiple access communication system according to a third aspect of the present invention cascade-connects each of the spreading units to a preceding spreading unit and a two-stage spreading unit adjacent thereto. It was made.

According to a fourth aspect of the present invention, there is provided a modulation apparatus for a code division multiple access communication system, wherein a spread signal generated by a spread signal generator of one of the spread units cascade-connected in each spread unit. And a delay unit for delaying the timing of the spread signal generated by the spread signal generation unit of the spreading unit at the next stage by one clock.

According to a fifth aspect of the present invention, there is provided a modulation apparatus for a code division multiple access communication system, wherein each output signal from a cascade-connected preceding or two-stage preceding spreading unit is selectively supplied to each of the spreading units. And a selection means for selectively inputting the output signal output from the adder or the output signal output from the adder to the cascade-connected next-stage or next-stage spreader unit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a modulator of a CDMA communication system according to the present invention. In FIG. 1, reference numerals 20-1, 20-2, 20-3,..., 20- (N-1),
20-N are diffusion units connected in cascade with each other, which will be described in detail. First, diffusion unit 2
The output terminal of 0-1 is the wiring 24-1 on the back plane 21.
Is connected to a second input terminal of the next-stage diffusion unit 20-2 and a first input terminal of the next-stage diffusion unit 20-3.

The output terminal of the diffusion unit 20-2 is connected to the second input terminal of the diffusion unit 20-3 of the next stage and the diffusion unit 20-4 of the next stage via the wiring 24-2 on the back plane 21. It is connected to the first input terminal. Further, the output terminal of the diffusion unit 20- (N-1) is connected to the second input terminal of the next diffusion unit 20-N and the first input terminal of the selector unit 22 via the wiring 24-N on the back plane 21. Connected to the terminal, diffusion unit 2
The output terminals 0-N are connected to the second input terminal of the selector unit 22 via the wiring 25 on the back plane 21. Reference numeral 23 denotes a monitoring control unit that outputs a control signal for selecting one of the input signals of the first input terminal and the second input terminal.

On the other hand, the configuration of each of the diffusion units 20-1 to 20-N is shown in FIG. According to this, the first input terminal IN-1 and the second input terminal IN-2 are connected to the selector 2 as the input signal selection means.
02, an input terminal of a signal from the monitoring control unit 23 is connected to the selector 202, and an output terminal of the selector 202 is connected to one input terminal of the adder 200.
The output terminal of the spread signal generation unit 202 is connected to the adder 200.
, And the output terminal of the adder 200 is connected to the output terminal OUT.

Next, the operation will be described. First, at the time of normal operation, each of the spreading units 20-1 to 20-N adds the signal input to the respective second input terminal IN-2 and the signal generated by the spreading signal generation unit 201 to each other. , From the output terminal OUT. Selector unit 2
2 outputs a signal input to the second input terminal. On the other hand, a diffusion unit, for example, the diffusion unit 20
If -3 is a fault or has been removed, as shown in FIG. 3, the monitoring control unit 23 detects this, and the spreading unit 20-4 at the next stage of the corresponding spreading unit 20-3 becomes A signal input to the first input terminal IN-1,
That is, the output signal from the spreading unit 20-2 preceding the corresponding spreading unit 20-3 and the spread signal generation unit 20
Control is performed so as to add the signal generated in step 1 and output from the output terminal OUT. In the case where the spreading unit which is the obstacle is the N-th spreading unit 20-N, the selector unit 22 outputs the signal input to the first input terminal IN-1, that is, the spreading unit in the preceding stage of the corresponding spreading unit. Control is performed so that the output signal from 20- (N-1) is output from the selector unit 22.

In general, the spread signal has a high signal rate, the chip rate in a modulator of a CDMA communication system based on IS-95A is 1.2288 MHz, and if serial transmission is performed to further reduce the number of signal lines, If so, the signal rate will be higher. For example, when transmitting at a rate of 19.6608 MHz, which is 16 times the chip rate, since one clock is only about 50 nsec, a signal from a certain spreading unit is transmitted to a selector unit through an adder in a subsequent spreading unit. The signal cannot be transmitted correctly due to the delay until the delay. Therefore, in the present invention, even when the signal rate is high, transmission is performed correctly.

FIG. 4 shows a configuration inside the diffusion unit 20 applied to such a case. In this spreading unit 20, the first input terminal IN-1 is connected to a first delay device 203 as a delay device, and the output terminal of the first delay device 203 and the second input terminal IN-2 are connected to a selector 202. It is connected to the. An input terminal of a signal from the monitoring control unit 23 is connected to the selector 202, and an output terminal of the selector 202 is connected to one input terminal of the adder 200. Further, the output terminal of the spread signal generation unit 201 inside the spread unit 20 is connected to the other input terminal of the adder 200, and the output terminal of the adder 200 is connected to the second delay unit 204 as a delay unit. ing. The output terminal of the second delay unit 204 is connected to the output terminal OUT of the diffusion unit 20.

Therefore, in this embodiment, the timing of the spread signal generated by the spread signal generator 201 of a certain spreading unit 20 is adjusted by the spread signal generated by the spread signal generator 201 of the next spreading unit 20. In this case, the timing in the adder 200 can be made to match by making the timing earlier by one clock. As a result, in all the spreading units 20, the timing of the spreading signal generated by the spreading signal generating unit 201 is one clock cycle longer than the timing of the signal generated by the spreading signal generating unit 201 of the similar spreading unit 20 at the next stage. Correction of the same timing, ie, earlier timing, enables correct transmission.

Next, a diffusion unit 20 as shown in FIG.
The operation of the modulation device using the above will be described. First, in the normal operation, for example, as shown in FIG.
The signal 0-3 from the first input terminal IN-1 is delayed by one clock by the first delay unit 203 and input to the selector 202. The signal from the second input terminal IN-2 is supplied to the selector 202. , And is selected by a signal from the monitoring control unit 23. And the selector 2
02 is added to the spread signal generated by the spread signal generation unit 201 by the adder 200, then delayed by one clock by the second delay unit 204, and output terminal OUT
Output from

On the other hand, for example, the diffusion unit 20-3 is shown in FIG.
In the case of a failure or removal, as shown in (2), the monitoring control unit 23 detects this, and the diffusion unit 20-4 at the next stage of the corresponding diffusion unit 20-3 sets the second
, Ie, the diffusion unit 20-2 in the preceding stage of the corresponding diffusion unit 20-3.
, And the spread signal generated by the spread signal generation unit 201 are added, and the output signal is controlled to be output from the output terminal OUT. If the failure diffusion unit is the N-th diffusion unit 20-N, the selector unit 22 outputs the second input terminal IN of the diffusion unit 20-N.
Control is performed so that the signal input to −2, that is, the output signal from the diffusion unit 20- (N−1) preceding the corresponding diffusion unit 20-N is output from the selector unit 22.

Thus, each of the diffusion units 20-1 to 20-2
The signal from the first input terminal IN-1 of 0-N is delayed by one clock in the first delay unit 203 and input to the selector 202, whereby the signal output from the diffusion unit in the preceding stage is output. The timing and the timing of the signal output from the second-stage spreading unit match at the input of the selector 202. Note that, of the wirings shown in FIGS. 1 and 2, the wiring shown by a thick line indicates a path for transmitting a signal.
Note that the amount of delay in the first delay unit 203 and the second delay unit 204 of each of the spreading units 20-1 to 20-N may be matched with the timing for accelerating the signal generated by the spreading signal generation unit 201. For example, two clocks may be used instead of one clock.

FIG. 5 shows another embodiment of the present invention.
Here, N diffusion units 30-1, 30-2,.
30-N are sequentially cascaded. That is, the diffusion unit 30-1 in FIG.
Is shown as a representative. The first output terminal OUT-1 is wired-OR connected with the second output terminal OUT-2 of the diffusion unit 30-2 at the next stage, and the wiring 3 on the back plane 31 is connected.
Via 4-2, it is connected to the input terminal I of the diffusion unit 30-3 in the next stage. The second output terminal OUT-1 of the diffusion unit 30-1 is connected to the input terminal I of the diffusion unit 30-2.

The first output terminal OUT-1 of the diffusion unit 30-2 is wired OR-connected with the second output terminal OUT-2 of the diffusion unit 30-3 at the next stage, and the wiring 34 on the back plane 31 is connected. It is connected to the input terminal I of the diffusion unit 30-4 in the next stage via -4. Further, the first output terminal OUT-1 of the diffusion unit 30- (N-1) is wired-OR connected with the second output terminal OUT-2 of the next diffusion unit 30-N, and the wiring on the back plane 31 is connected. 34-N is connected to the addition signal output terminal 32. The second output terminals OUT-2 of the diffusion units 30-3 and 30- (N-2) are connected to the input terminals I of the diffusion units 30-4 and 30- (N-1) of the next stage, respectively. Have been.

The structure of the diffusion units 30-1 to 30-N used in the embodiment will be described with reference to FIG. That is, the spreading unit 30 adds the input signal input to the input terminal IN to the signal generated by the spreading signal generator 301 in the adder 300, and outputs the added output to a three-state buffer as output selection means. The signal is output to the first output terminal OUT-1 via the output terminal 303 and to the second output terminal OUT-2 via the three-state buffer 302 as output selection means.

Therefore, the diffusion units 30-1 to 30-3
By using 0-N, during normal operation,
Each of the diffusion units 30-1 to 30-N as shown in FIG.
By setting each of the first output terminals OUT-1 to high impedance, the added output of the input signal input to each of the input terminals IN and the signal generated by the spread signal generation unit 301 becomes the second output. Output from terminal OUT-2. In this case, for example, the diffusion unit 30-
If 3 is faulty or has been removed,
As shown in FIG. 7, the monitoring control unit 33 detects this, and the diffusion unit 30 in the preceding stage of the corresponding diffusion unit 30-3.
The output signal from the first output terminal OUT-1 is output by setting the -2 second output terminal OUT-2 to high impedance. Thereby, the corresponding diffusion unit 30
The output signal of the diffusion unit 30-2 in the preceding stage of the corresponding diffusion unit 30-3 can be input to the input terminal of the diffusion unit 30-4 in the stage following −3.

FIG. 8 shows another embodiment of the diffusion unit 30. In the spreading unit 30, for example, an input terminal IN of the spreading unit 30 shown in FIG. 5 is connected to a first delay device 304 as a delay device, and an output terminal of the first delay device 304 is connected to one input terminal of the adder 300. Connected to terminal. Also, the input terminal of the spread signal generation unit 301 is connected to the other input terminal of the adder 300,
One of the output terminals is delayed by one clock in a second delay unit 305 as a delay unit, and then connected to a first output terminal OUT-1 via a three-state buffer 303. One is a 3-state buffer 30 as it is.
2 is connected to the second output terminal OUT-2.

Therefore, in such an embodiment, the spread signal timing generated by the spread signal generation unit 301 of a certain spreading unit 30 is changed by the signal generated by the spread signal generation unit 301 of the next spreading unit 20. In this case, the timing in the adder 300 can be made to match by making the timing earlier by one clock. Accordingly, in all the spreading units 20, the timing of the spreading signal generated by the spreading signal generating unit 301 is advanced by one clock from the timing of the signal generated by the spreading signal generating unit 301 of the next-stage spreading unit 20. By correcting the timing of the above, correct transmission can be performed.

Next, the operation of the modulator using the spreading unit 20 as shown in FIG. 8 will be described. First, during normal operation, as shown in FIG.
The signal from the input terminal IN of −3 is supplied to the first delay unit 304.
, And is added to the spread signal generated by the spread signal generation unit 301 by the adder 300, and
One is delayed from the first output terminal OUT-1 via the three-state buffer 303 after being delayed by one clock in the second delay unit 305. The other is directly output from the second output terminal OUT-2 via the three-state buffer 302.

On the other hand, for example, the diffusion unit 30-3 is arranged as shown in FIG.
In the case where a fault has occurred or the fault has been removed, the monitoring control unit 33 detects this, and the second output terminal OUT- of the spreading unit 30-2 preceding the corresponding spreading unit 30-3. 2 is set to high impedance, and control is performed so as to output an output signal from the first output terminal OUT-1. Thus, the output signal of the diffusion unit 30-2 in the preceding stage of the corresponding diffusion unit 30-3 can be input to the input terminal IN of the diffusion unit 30-4 in the next stage of the corresponding diffusion unit 30-3. At this time, since the timing of the signal output from the preceding diffusion unit 30-2 is delayed by one clock in the first delay unit 304, the signal is input to the input terminal IN of the next diffusion unit 30-4. Timing matches. In addition, each diffusion unit 30-1 ~
30-N first delay unit 304 and second delay unit 30
The amount of delay at 5 is not limited to one clock, but may be, for example, two clocks, as long as the timing of accelerating the spread signal generated by the spread signal generation unit 301 is matched.

[0030]

As described above, according to the first aspect of the present invention, a code division unit adds and multiplexes spread signals of a plurality of channels spread-modulated by a plurality of spreading units with a spreading code by an adder. In the modulation apparatus for a multiple access communication system, the output terminals of the plurality of spreading units are connected to other spreading units.
Cascade connected to the input terminals of the unit.
The diffusion units are respectively input from the input terminals.
Built-in addition of internally generated spread signal to operation data
And a new result is output from the output terminal.
Since the output signal is output as arithmetic data, even if the number of channels of the output signal increases as in the case where the output signal from the spreading unit is output separately for I and Q or parallel output An increase in the number of signal lines between a certain diffusion unit and an addition unit can be prevented, and as a result, the effect of simplifying the wiring on the backplane and the device configuration can be obtained.

According to the second and third aspects of the present invention, each of the diffusion units is configured to be cascade-connected to a diffusion unit of a preceding stage and a diffusion unit of two stages before the adjacent diffusion unit. Even if one spreading unit fails or is removed, the output signal from the preceding spreading unit of the one spreading unit can be transmitted to the next spreading unit of the one spreading unit. Thus, the outputs of the other spreading units except for the one spreading unit can be sequentially added and output, and the effect of preventing an error in the modulation output can be obtained.

Further, according to the invention of claim 4, in each of the spreading units, the timing of the spreading signal generated by the spreading signal generating unit of one of the spreading units cascade-connected is the next stage. Since the delay unit that delays the timing of the spread signal generated by the spread signal generation unit of the spread unit by one clock is provided, the addition timing of the spread signal in the adder in each spread unit can be matched. The effect is obtained that correct signal transmission can be performed even when the rate is high.

According to the fifth aspect of the present invention, each output signal from the cascade-connected pre-stage or two-stage pre-stage diffusion unit is selectively input to the adder. Selection means for selectively inputting the output signal output from the adder to a cascade-connected next-stage or next-stage diffusion unit is provided. And the other diffusion units except for the diffusion unit removed or removed can be maintained in the normal cascade connection state.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a modulation device of a code division multiple access communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a diffusion unit in FIG.

FIG. 3 is a block diagram showing a modulation device of the code division multiple access communication system when a failure spreading unit occurs in FIG. 1;

FIG. 4 is a block diagram showing another internal configuration of the diffusion unit in FIG. 1;

FIG. 5 is a block diagram showing a modulation device of a code division multiple access communication system according to another embodiment of the present invention.

FIG. 6 is a block diagram showing an internal configuration of a diffusion unit in FIG. 5;

FIG. 7 is a block diagram showing a modulator of the code division multiple access communication system when a failure spreading unit occurs in FIG.

8 is a block diagram showing another internal configuration of the diffusion unit in FIG.

FIG. 9 is a block diagram illustrating a modulation device of a conventional code division multiple access communication system.

[Explanation of symbols]

 20-1 to 20-N, 30-1 to 30-N Spreading unit 200, 300 Adder 202 Selector (selector) 203, 204, 304, 305 Delayer 302, 303 3-state buffer (selector)

Claims (5)

(57) [Claims] 1. A modulation device for a code division multiple access communication system, wherein an adder adds and multiplexes spread signals of a plurality of channels spread-modulated by a spreading code by a plurality of spreading units. If the output terminal of the unit is connected to another diffusion unit
Cascade-connected to the input terminals of the
Spread signal generated internally to the calculated data to the built-in adder
From the output terminal.
A modulation device for a code division multiple access communication system, which outputs the data as data . 2. The code division multiple access communication system according to claim 1, wherein each of the spreading units is cascaded to a next spreading unit and a next spreading unit adjacent thereto. Modulation device. 3. The code division multiple access communication system according to claim 1, wherein each of the spreading units is cascaded to a preceding spreading unit and a two-stage spreading unit adjacent thereto. Modulation device. 4. The spread signal generation unit of the spreading unit in the next stage, in each of the spreading units, with respect to the timing of the spread signal generated by the spread signal generation unit of one of the cascaded spreading units. 2. The modulation apparatus for a code division multiple access communication system according to claim 1, further comprising a delay unit for delaying the timing of the spread signal to be performed by one clock. 5. An output signal output from a cascade-connected pre-stage or two-stage pre-stage diffusion unit is selectively input to the adder or output signal output from the adder. 2. The modulation apparatus for a code division multiple access communication system according to claim 1, further comprising: a selection unit for selectively inputting to a cascade-connected next-stage or next-stage spread unit.