JP3001707B2 - Spread spectrum communication equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a spread spectrum communication apparatus .

[0002]

2. Description of the Related Art In recent years, sliding correlators have been widely used for synchronization acquisition of a spread spectrum receiver.

Hereinafter, a conventional sliding correlator will be described with reference to the drawings. Here, the binarized baseband signal has one period 12 with 127 initial phases.
It is assumed that the signal is spread by a pseudo-noise sequence of 7 chip length.

FIG. 4 is a block diagram of a conventional sliding correlator. In FIG. 4, a pseudo noise sequence generator 1 generates a pseudo noise sequence on the receiver side. The multiplier 2 to which the input terminal a and the pseudo-noise sequence generator 1 are connected is connected to the counter 3 and multiplies the binarized baseband signal by the receiving-side pseudo-noise signal to output a coincidence signal to the counter 3. . The counter 3 counts the number of coincidence signals from the multiplier 2. The subtraction unit 4 connected to the counter 2 is connected to the comparison selection unit 5, and subtracts the output of the counter 2 to output the mismatch count to the comparison selection unit 5. Further, the comparison / selection unit 5 connected to the counter 2 and the subtraction unit 4 is connected to the threshold level storage unit 6 and the comparison unit 7, and the output of the counter 2 and the subtraction unit 4 outputs the larger one of the match count and the mismatch count. Is output. Comparison selection section 5
Can update the threshold level (threshold) to the output from the comparison / selection unit 5. The comparison unit 7 to which the comparison selection unit 5 and the threshold level storage unit 6 are connected compares the output from the comparison selection unit 4 with the initial threshold level or the updated threshold level.

A control unit 8 to which the comparison unit 7 is connected is connected to the pseudo noise sequence generation unit 1 and the threshold level storage unit 6 and controls mainly the pseudo noise sequence and the threshold level storage unit 6. The synchronization holding unit 9 to which the control unit 8 is connected holds the state after the establishment of the synchronization acquisition. Further, the one-period detection unit 10 is connected to the control unit 8 and detects one period of the pseudo noise sequence. Furthermore, it is connected to the control unit 8
The 127-chip sliding signal detector 9 detects that the one-chip sliding signal has been output 127 times. The above constitutes a sliding correlator.

The operation of the conventional sliding correlator configured as described above will be described below. First,
When one chip of the binarized baseband signal matches one chip of the pseudo-noise sequence output from pseudo-noise sequence generator 1 in multiplier 2 of the sliding correlator, a match signal is output from multiplier 2. You. The counter 3 counts the number of coincidence signals (coincidence count number) and outputs it for each period of the pseudo noise sequence, and the subtraction unit 4 outputs {mismatch count number} = 127 (the number of chips in one period of the pseudo noise sequence). Outputs {match count}. Further, the comparison / selection unit 5 compares the coincidence count output from the counter 3 with the mismatch count output from the subtraction unit 4, and selects and outputs the larger count.

For example, at the end of one cycle of the pseudo-noise sequence, any of the binarized baseband signals spread with the same pseudo-noise sequence output from pseudo-noise sequence generator 1 If the information of one period of the pseudo noise sequence is “1”, the phase of the pseudo noise sequence output from the pseudo noise sequence generator 1 and the pseudo noise sequence The phases are the same, the output of the counter 3 (the number of coincidence counts) is near 127, and the output of the subtraction unit 4 (the number of mismatch counts) is near 0. If the information of one period of an arbitrary pseudo noise sequence of a binarized baseband signal spread with the same pseudo noise sequence as the pseudo noise sequence output from the pseudo noise sequence generator 1 is “0”, When synchronization acquisition is established, the phase of the pseudo-noise sequence output from the pseudo-noise sequence generator 1 and the phase of the pseudo-noise sequence of the binarized baseband signal are exactly inverted. The (general count number) is around 0, and the output (mismatch count number) of the subtraction unit 4 is around 127.

Further, the threshold level storage unit 6 stores
An initial threshold level (threshold) is set as an initial setting, and the value of the threshold level storage unit 6 can be updated to an output from the comparison and selection unit 5 by a threshold level update signal output from the control unit 7. . Here, for the sake of explanation, the initial threshold level is set to 97.

The comparison unit 7 first compares the initial threshold level 97 of the threshold level storage unit 6 with the output of the comparison selection unit 5. At this time, {Initial Threshold Level 97}>
If {the output of the comparison / selection unit 5}, the threshold level update signal is not output from the control unit 8 based on this information, and the value of the threshold level storage unit 6 is not updated and recorded. Also,
｛Initial threshold level 97｝ <｝ Output of comparison and selection unit 5｝
Then, based on this information, a threshold level update signal is output from the control unit 8, and the value of the threshold level storage unit 6 is recorded and updated (updated threshold level m) to the output of the comparison and selection unit 5. Even after setting a new record, the initial threshold level is 97
The operation is the same as in the case of. This operation is repeated until the 127 chip sliding signal detection unit 11 outputs a 127 chip sliding completion signal.

The control unit 8 receives the one-cycle detection signal output from the one-cycle detection unit 10 and outputs a one-chip sliding signal. The one-chip sliding signal, which is a phase control signal, is input, and the pseudo-noise sequence generator 1 shifts the initial phase of the pseudo-noise sequence by one chip. Upon receiving the one-chip sliding signal from the controller 8 127 times, the 127-chip sliding signal detector 11 outputs a 127-chip sliding completion signal. If the controller 8 receives the 127-chip sliding completion signal and does not output the threshold level update signal, the above operation is repeated.
If the threshold level update signal has been output, the maximum detection timing signal is output to the synchronization holding unit 9 so that
Synchronous acquisition is established.

The synchronization holding unit 7 receives the maximum detection timing signal, and finally establishes the synchronization more precisely after the synchronization acquisition is established, based on the timing of the initial phase of the pseudo noise sequence when the record is updated in the threshold level storage unit 6 lastly. In addition, synchronization is maintained so that synchronization is not lost.

[0012]

However, in the above-mentioned conventional sliding correlator, the transmitter spreads the data of "0" and "1" at random until the receiver establishes synchronization acquisition, and transmits the data at random. , The sliding correlator has to distinguish and capture the data of “0” and “1”, so that the circuit scale becomes large, and is equal to one period of the pseudo noise sequence output from the pseudo noise sequence generation unit 1. Compare all phases of one cycle of the pseudo noise sequence of the binarized baseband signal spread by the pseudo noise sequence, and output a one-chip sliding signal based on the one cycle detection signal output from the one cycle detection unit 10. Therefore, there is a problem that it takes time to acquire synchronization.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a sliding correlator that can be reduced in size and cost, and that can acquire synchronization at high speed.

[0014]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention has a synchronous acquisition mode and a normal mode,
Baseband signal and the output from the pseudo-noise sequence generator.
Whether or not the pseudo-noise sequence matches is determined chip by chip
Determining means for determining, and the number of matches determined by the determining means;
Or a counter that counts the number of mismatches,
Updates the counter output value with the level update signal.
Threshold level storage for recording
In the synchronous acquisition mode, one cycle of the pseudo noise sequence is
Stores the output value of the counter when detected as a threshold level
In the threshold level storage section.
The bell and the output value of the counter are compared, and one round of the pseudo noise sequence
Period, or when the number of matches or
When the threshold level in the flash level memory is reached
Phase shifts the pseudo-noise signal on the receiving side of the pseudo-noise sequence generator to
This is a configuration in which

[0015]

[0016]

According to the above configuration, the transmitter of the spread spectrum communication apparatus transmits only fixed value data for a certain period of time after the call is made. Therefore, the circuit scale for the random data can be reduced, so that the circuit size can be reduced and the cost can be reduced. Becomes possible. Further, one cycle of the pseudo noise sequence output from the pseudo noise sequence generation unit and all phases of one cycle of the pseudo noise sequence of the binarized baseband signal spread by the same pseudo noise sequence need not be compared. However, since the one-chip sliding signal is output, for example, when the mismatch count becomes equal to or more than the initial threshold level or the update threshold level, faster synchronization acquisition is realized as compared with the related art.

[0017]

An embodiment of the present invention will be described below with reference to the drawings. Note that, similarly to the conventional example, the binarized baseband signal has a period of 12
It is assumed that the signal is spread by a pseudo noise sequence having a length of 7 chips.

FIG. 1 is a block diagram of a sliding correlator in a receiver of a spread spectrum communication apparatus according to one embodiment of the present invention. In FIG. 1, a pseudo noise sequence generator 11
Is a phase control signal that controls the same in-phase or opposite-phase pseudo-noise sequence similar to a binarized baseband signal spread by a 127-chip-length pseudo-noise sequence having 127 initial phases. And occur. A multiplying unit 12 serving as a judging means for judging coincidence or non-coincidence is connected to an input terminal a and a pseudo-noise sequence generating unit 11, and is connected to a counter 13, and one chip of a binarized baseband signal and a pseudo-noise sequence 1 of the pseudo-noise sequence output from the generator 11
The result is multiplied by the chip and a mismatch signal is output to the counter 13.
The counter 13 counts the number of mismatches (the number of mismatch counts) and sequentially outputs them. The threshold level storage unit 14 to which the counter 13 is connected has an initial threshold level (threshold) set in advance, and can update and record the output (update threshold level) of the counter by a threshold level update signal. Also a counter
Comparison section to which 13 and threshold level storage section 14 are connected
15 compares the mismatch threshold value with the initial threshold level or the updated threshold level in the threshold level storage unit.

Further, the control unit 16 to which the comparison unit 15 is connected includes the pseudo noise sequence generation unit 11 and the threshold level storage unit 14
, And mainly controls the pseudo noise sequence and the threshold level storage unit 14. Further, the synchronization holding unit 17 to which the control unit 16 is connected holds the state after synchronization acquisition is established. further,
The one-period detector 18 connected to the controller 16 detects one period of the pseudo-noise sequence. Further, 127 connected to the control unit 16
The chip sliding signal detector 19 detects that one chip sliding signal has been output 127 times. The control unit 16 includes a synchronization holding unit 17, a period detecting unit 18 and a 127 chip sliding signal detecting unit 19, which constitute a control unit. When the 1 period detecting unit 18 detects one period of the pseudo noise sequence, a threshold level update signal And outputs a phase control signal when one cycle of the pseudo-noise sequence is detected or when the mismatch count is greater than the initial threshold level or the updated threshold level, and when the phase control signal is detected n times and the pseudo-noise is detected. When one cycle of the sequence is detected, a maximum detection timing signal is output to establish synchronization acquisition.

The operation of the sliding correlator in the receiver of the spread spectrum communication apparatus configured as described above will be described below. The spread spectrum communication apparatus shown here is for one-way communication. As shown in FIG. 2, the transmitter transmits only "1" data for a certain period of time after calling, and transmits actual random data after a lapse of this predetermined period. Within this fixed time, the receiver shall establish synchronization acquisition. That is, the transmitter transmits only fixed value data until the receiver establishes synchronization acquisition, and transmits actual data from the time when the receiver establishes synchronization acquisition.

First, one multiplier of the binarized baseband signal and one of the pseudo noise sequence output from the pseudo noise sequence generator 11 are supplied to the multiplier 12 of the sliding correlator of the receiver.
The chips are input and multiplied, and when they do not match, a mismatch signal is output from the multiplier 2. counter
In 13, the number of mismatched signals is counted, and the mismatched count, which is a count value of one cycle (127 chip length) or less for the pseudo noise sequence, is output. The mismatched count is input to the comparator 15 and the threshold level storage 5. Is done.

Since any one bit of the baseband signal binarized until the establishment of the synchronization acquisition is "1", the baseband signal is binarized with the phase of the pseudo noise sequence output from the pseudo noise sequence generator 11. The phase of the pseudo-noise sequence of the baseband signal is the same, and the output of the counter 13 becomes 0 when synchronization acquisition is established.
Be near.

An initial threshold level (threshold) is set in the threshold level storage unit 14 as an initial setting, and the threshold level update signal output from the control unit 16 causes the values in the threshold level storage unit 14 to be different. It can be updated to the count number. Here, for the sake of explanation, the initial threshold level is set to 30 as shown in FIG. Here, the relationship between the mismatch count and the counter 13 will be described. The hatched area A is a one-chip sliding signal generation area. When the mismatch count exceeds the initial threshold level of 30 and enters the one-chip sliding signal generation area A, even if the mismatch count is further counted, it cannot be smaller than the initial threshold level. Therefore, the counting may be stopped at this point, and the comparison may be performed with the pseudo noise sequence of the next initial phase. Therefore, it is set so that the count number of the counter 13 is always output. First, the comparing unit 15 compares the initial threshold level 30 of the threshold level storage unit 14 with the output of the counter 13 (the number of mismatch counts). At this time, if {initial threshold level 30} ≦ {mismatch count number}, the threshold level update signal is not output from the control unit 16 based on this information, and the value of the threshold level storage unit 14 is not updated and recorded. At the same time, the controller 16 outputs a one-chip sliding signal, the pseudo-noise sequence generator 1 shifts the initial phase of the pseudo-noise sequence by one chip, a clear signal is output from the controller 16, and the one-period detector 18 is cleared. Is done. Control unit
When a one-cycle detection signal is input to the 16 from the one-cycle detection unit 8, if {initial threshold level 30}> {mismatch count number}, a threshold level update signal is output from the control unit 16 based on this information, and the threshold level is set. Storage unit 14
Is updated to the output of the counter 13 (the number of mismatch counts) (update threshold level m). Then, after the record is updated, it operates at the update threshold level m. This behavior
This is repeated until the 127 chip sliding signal detection unit 19 outputs a 127 chip sliding completion signal.

This 127 chip sliding signal detecting section
19 is a one-chip sliding signal from the control unit 16 at 127
When the input is performed twice, a chip sliding completion signal is output. The control unit 16 receives the 127 chip sliding completion signal, repeats the above operation if the threshold level update signal has not been output, and if the threshold level update signal has been output, outputs the maximum detection timing signal to the synchronization holding unit. By outputting to 17, synchronization acquisition is established.

The synchronization holding unit 17 receives the maximum detection timing signal, and finally establishes synchronization more precisely after the establishment of synchronization acquisition by the timing of the initial phase of the pseudo-noise sequence when recording and updating are finally performed in the threshold level storage unit 14. Maintain synchronization so that synchronization is not lost.

[0026]

As described above, according to the present invention, since the transmitter of the spread spectrum communication apparatus transmits only fixed value data for a certain period of time during a call, the circuit for data other than the fixed value can be omitted. The circuit scale can be reduced and the cost can be reduced. Also, it is not necessary to compare all phases of one period of the pseudo-noise sequence of the binarized baseband signal spread with the same pseudo-noise sequence as one period of the pseudo-noise sequence output from the pseudo-noise sequence generator. For example, when the mismatch count is equal to or more than the initial threshold level or the update threshold level, a one-chip sliding signal is output, so that high-speed synchronization acquisition can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a sliding correlator according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation of the spread spectrum communication apparatus according to one embodiment of the present invention.

FIG. 3 is a graph illustrating the operation of FIG. 1;

FIG. 4 is a block diagram showing a configuration of a conventional sliding correlator.

[Explanation of symbols]

 11 Pseudo noise sequence generation unit 12 Multiplication unit 13 Counter 14 Threshold level storage unit 15 Comparison unit 16 Control unit 17 Synchronization holding unit 18 One-cycle detection unit 19 127 Chip sliding signal detection unit

Claims (3)

(57) [Claims] A transmitter transmits n pieces of transmission data with n initial phases.
Spread with a pseudo-noise sequence of one cycle and n chips long for transmission
However, the receiver generates a pseudo-noise signal on the receiving side.
Therefore, it is a spread spectrum method that restores the signal,
The transceiver sends fixed value data until the receiver establishes synchronization acquisition.
The actual data from the time the receiver establishes synchronization
Is a spread spectrum communication apparatus for transmitting a signal , wherein the receiver has a synchronization acquisition mode and a normal mode.
In- phase similar to the pseudo-noise sequence included in the received signal
Or a pseudo-noise system that outputs a pseudo-noise signal on the receiving side in opposite phase
A column generator, a received baseband signal and the pseudo noise sequence generator,
One pseudo check whether the pseudo noise sequences output from the
Cow determination means for each flop, the number of clicks or mismatch match determined by said determining means
Counter and threshold level update signal
The output value of the counter is recorded as an update threshold level.
And a threshold level storage unit for recording.
When one cycle of the pseudo noise sequence is detected in the
The output value of the counter is stored in the threshold level
The threshold level of the threshold level storage unit
The output value of the counter is compared, and one cycle of the pseudo noise sequence
Is detected, or the number of matches or
When the threshold level in the refresh level memory has been reached
Phase of the pseudo-noise signal on the receiving side of the pseudo-noise sequence generator.
The phase control signal is shifted n times,
A configuration for detecting one cycle of a noise sequence and establishing synchronization acquisition;
A spread-spectrum communication device characterized in that: 2. The transmitter according to claim 1, wherein the transmitter has n initial phases of the transmission data.
Spread with a pseudo-noise sequence of one cycle and n chips long for transmission
In the receiver, the pseudo-noise system included in the received signal
By generating a receiver pseudo-noise signal similar to the
Is a spread spectrum method that restores the signal by
Transmits fixed value data until receiver establishes synchronization acquisition
And the actual data from when the receiver establishes synchronization
A spread spectrum communication apparatus for transmitting, the receiver has a synchronization capture mode and the normal mode, the sliding correlator in the receiver, a control unit, a pseudo-noise sequence included in the received baseband signal A similar in-phase or opposite-phase pseudo-noise signal on the receiving side is transmitted to the control means.
A pseudo-noise sequence generating unit that outputs a phase-shifted signal by a phase control signal from a stage, and whether one chip of the baseband signal matches one chip of the pseudo-noise sequence output from the pseudo-noise sequence generating unit Determining means for determining whether or not the number of inconsistencies is determined by the determining means;
A counter for outputting a value, further the output value of the counter by the threshold level update signal is pre-initialized Suresshurebe Le set
A threshold level storing unit that updates recorded as a new threshold level, and a comparator for comparing the number of initial threshold levels or updated threshold level and the mismatch count of the threshold level storing unit, said control means synchronization acquisition mode
In the above, when one period of the pseudo noise sequence is detected, the threshold level update signal is output and the output of the counter is output.
The value is stored in the threshold level storing unit, position when mismatch count by comparing the result of or the comparison unit when it detects a cycle of the pseudo-noise sequence is greater than the initial threshold levels or further <br/> new threshold level spectrum characterized by a phase control signal to the output to the pseudo-noise sequence generator, and configured to establish the detected synchronous capture one cycle of the pseudo noise sequence and detects n times phase control signal
Spreading communication device . (3)The transmitter has n initial phases of transmitted data.
Spread with a pseudo-noise sequence of one cycle and n chips long for transmission
In the receiver, the pseudo-noise system included in the received signal
By generating a receiver pseudo-noise signal similar to the
Is a spread spectrum method that restores the signal by
Transmits fixed value data until receiver establishes synchronization acquisition
And the actual data from when the receiver establishes synchronization
A spread spectrum communication device for transmitting, The receiver has a synchronization acquisition mode and a normal mode, A sliding correlator in the receiver, Control means; Same as the pseudo-noise sequence included in the received baseband signal.
The same in-phase or out-of-phase pseudo-noise signal on the receiving side
Pseudo-shift output by phase control signal from stage
A similar noise sequence generator, One chip of the baseband signal and the pseudo-noise sequence
One chip of the pseudo-noise sequence output from the raw part matches
Determining means for determining whether or not Count the number of matches determined by the determination means and count
A counter that outputs a value, The initial threshold level is set in advance,
The output value of the counter is updated by the flash level update signal.
Threshold level updated and recorded as a new threshold level
Storage unit, The initial threshold level in the threshold level storage unit
Or update threshold level and the above match count
And the comparison section And wherein the control means in the synchronization acquisition mode
The threshold level when one cycle of the noise sequence is detected
Output an update signal and threshold the output value of the counter.
Detect one period of pseudo noise sequence by storing it in the level storage unit
Match count according to the comparison result of the comparison unit
The number is the initial threshold level or the updated threshold level
When the phase control signal is larger than the
Output to the raw part, detect and control the phase control signal n times
A configuration for detecting one period of a similar noise sequence and establishing synchronization acquisition
A spread-spectrum communication device, characterized in that: