JPH05327658A - Spread spectrum communication equipment, transmission state detector and radio communication equipment - Google Patents

Abstract

PURPOSE:To block a disturbance wave due to the frequency common use with a narrow band system by detecting received power for a band in which a narrow bad disturbing wave is generated and eliminating the band signal and applying inverse spread the remaining signal when the power exceeds a prescribed power. CONSTITUTION:Only a desired signal band component is extracted from a signal inputted to a reception antenna 101 by an RF filter 102 eliminating an undesired band signal and the desired component is amplified and it is inputted to a band pass filter(BPF) 105 which passes only a signal at a frequency band for a disturbing wave signal generated from a narrow band system in common use and subject to square detection and the result is inputted to a discrimination circuit 107. When no excess disturbing wave is mixed in the reception signal, the input of a switch 108 connects to ground and stable demodulation is implemented. On the other hand, when an excess disturbing wave is mixed, the input side of the switch 108 is connected to an output of the BPF 105, and an adder 109 generates a signal resulting from eliminating the pass band signal of the BPF 105, that is, only the band signal for the disturbing wave from an output of the delay circuit 104.

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 which operates by sharing the same frequency as an existing narrow band system.

[0002]

2. Description of the Related Art Generally, a spread spectrum communication device has an interference elimination capability as one of its characteristics, and even if a narrow band interference wave exists in a reception band,
The interfering wave is diffused in the process of despreading, and the interfering wave power at the time of demodulation becomes about 1 / spread ratio as compared with the interfering wave power before despreading.

For this reason, it is considered that the anti-jamming performance is twice as high as that of a normal narrow band system. Figure 2
A signal waveform at the time of reception in such a spread spectrum communication device is shown. That is, FIG. 2A is a spectrum signal waveform at the receiving end of the spread spectrum communication device, FIG. 2B is a spectrum signal waveform after despreading, and FIG. 2C is a narrowband filter after despreading. It is a spectrum signal waveform after passing (before data demodulation).

[0004]

However, when such a spread spectrum communication device is operated by sharing the same frequency with an existing narrow band system, narrow band interference frequently occurs and the receiver installation position is high. In some cases, the interference wave power becomes extremely large, the probability of exceeding the interference exclusion capability of the spread spectrum communication device becomes high, and there is a drawback that stable communication quality cannot be maintained.

FIG. 3 shows a signal waveform in such a case. That is, FIG. 3A is a spectrum signal waveform at the receiving end of the spread spectrum communication device,
FIG. 3B is a spectrum signal waveform after despreading, and FIG.
(C) is a spectrum signal waveform after despreading and after passing a narrow band filter (before data demodulation).

As shown in the figure, after despreading, a non-negligible interference wave remains in the signal after passing through the narrow band filter.

It is an object of the present invention to provide a spectrum communication device capable of blocking an interference wave due to sharing the same frequency with a narrow band system, for example.

[0008]

According to the present invention, the received power in a band in which a narrow band interference wave is generated is detected, and when the power exceeds a predetermined value, despreading is performed after removing the band signal. As a result, when an extremely large level of interference wave is input, it is possible to remove the interference wave and ensure stable communication quality.

[0009]

1 is a block diagram showing the structure of a receiving section of a spectrum communication apparatus according to a first embodiment of the present invention.

The receiving section includes a receiving antenna 101, an RF filter (BPF) 102 for removing an unnecessary band signal in a received wave, and an RF for amplifying the filter output.
Amplifier 103 and delay circuit 104 having a predetermined delay amount
And a band pass filter (BPF) 105 having the same delay characteristic as that of the delay circuit 104 and passing only a preset band signal, and for reducing the output of the band pass filter 105 from the output of the delay circuit 104. Adder 109
A detection circuit 106 that detects the output of the bandpass filter 105, a determination circuit 107 that compares the output of the detection circuit 106 with a preset voltage, and the determination circuit 1
It has a switch 108 that opens and closes between the bandpass filter 105 and the adder 109 based on the output of 07, and a demodulator 110 that demodulates the output signal of the adder 109.

In the above configuration, the receiving antenna 101
When a signal is input to, the BPF 102 extracts only the desired signal band component and outputs it to the RF amplifier 103. The RF amplifier 103 amplifies the input signal to a predetermined level.

The output of the RF amplifier 103 is
It is input to the BPF 105 that allows only signals in the frequency band of the interference wave signal generated by the shared narrow band system to pass,
The output of the BPF 105 is square-law detected by the detection circuit 106 and input to the determination circuit 107. The detection output at this time is a voltage signal having a value substantially proportional to the interfering wave power.

Therefore, the judgment circuit 107 compares the input detection output with a preset voltage level, and if the detection output does not exceed the voltage level, the switch 1
When the input of 08 is selected to the ground side and the detection output exceeds the voltage level, the input of switch 108 is set to BPF.
Select to 105 side. As a result, the output of the switch 108 is input to the adder 109.

On the other hand, the output of the RF amplifier 103 is input to the delay circuit 104 and given the same delay amount as the delay characteristic of the BPF 105. The output of the delay circuit 104 is input to the adder 107.

In the adder 109, the delay circuit 104
The output of the demodulator 1 is subtracted from the output of the switch 108.
It is output to 10. The demodulator 110 executes ordinary spread spectrum demodulation such as despreading and data demodulation.

As described above, when the excessive interference wave is not mixed in the received signal, the input side of the switch 108 is grounded, and the output of the adder 109 is the delay circuit 10.
4 is the output itself, and the spectrum signal waveform at this point is as shown in FIG. 2 (a) described above, and the spectrum signal waveform after despreading and before data demodulation is also shown in FIG. 2 (c) described above. As shown, the desired wave-to-interference ratio is large, and stable demodulation is possible.

On the other hand, when an excessive interference wave is mixed in the received signal, the input side of the switch 108 is connected to the BPF 105.
Connected to the output of the delay circuit 104 and the BPF 10
Since 5 has the same delay characteristic, the adder 109 generates a signal in which only the pass band of the BPF 105, that is, the band of the interference wave is removed from the output of the delay circuit 104.

The spectrum signal waveform in this case is shown in FIG.
As shown in (a). Therefore, after despreading, the spectrum signal waveform before data demodulation becomes as shown in FIG. 4C, so that the interference wave is removed and stable demodulation becomes possible.

FIG. 5 is a block diagram showing a second embodiment of the present invention. This example is the delay circuit 10 of the first embodiment.
4, the switch 108 and the adder 109 are only replaced by the band elimination filter (BEF) 111 and the switch 112, so only this part will be described.

The output of the RF amplifier 103 is the BEF111.
Entered in. The BEF 111 removes only a band signal in which a preset interfering wave is generated from this input signal and outputs it to the switch 112. The other input of switch 112 is the output of RF amplifier 103.

In the above configuration, when an excessive interference wave is mixed in the input signal, the input of the switch 112 is selected to the BEF 111 side by the output of the determination circuit 107, and the input of the demodulator 110 is selected. Do not mix excessive interference waves. On the other hand, when an excessive interference wave is not mixed in the input signal, the input of the switch 112 is selected on the output side of the RF amplifier 103, and demodulation is possible at this time as well.

Next, a third embodiment of the present invention will be described from the background thereof.

Generally, when digital data communication is performed by a wireless communication device, it is considered that a protocol having a resending procedure as well as error correction is necessary due to the problem of line quality. For this reason, a packet format that can facilitate the retransmission procedure is used for data transmission, and HDLC (High Lev
el Data Link Control Procedure).

6 and 7 show an example of a retransmission procedure in HDLC, which will be described below with reference to this figure.

First, in FIG. 6, Rej (Reject)
The procedure is shown, and the data I in packet form is transmitted from the data transmission device. Then, as indicated by I _1-5 (fifth data of I frame 1), the transmission data is damaged,
When the data does not reach the data receiving wireless device, the data transmitting wireless device waits for reception until the reception confirmation timer T2 expires. When the time is over, after sending RR (Receive Ready), the retransmission timer T1 is turned on and waits for a response from the data transmitting wireless terminal.

On the other hand, in the data transmission radio apparatus, the poll bit p (reception confirmation request bit) is set to 1 and I _1-5 (I
_1-5.p = 1), then turn on the T1 timer
Wait for confirmation until the timer expires.

However, as shown in FIG. 6, since the RR sent by the data receiving radio device is damaged like the data and is not received by the data transmitting radio device, the T1 timer in the data transmitting radio device expires. Therefore, the data transmission wireless device sets the RR in which the pole bit p is set to 1.
To restart the timer after clearing the T1 timer. If there is no response from the data receiving wireless device before the T1 timer times out again, the same retransmission operation is repeated up to N2 times.

Next, the data receiving wireless device which has received the RR from the data transmitting wireless device stores the transmission state variable (variable indicating the value of the data I transmitted by the data transmitting wireless device + 1) indicated by RR in the same device. The received state variable (a variable indicating the value of the data I that the data receiving wireless device has correctly received + 1) is collated.

When the two values are different, the Rej command carrying the reception state variable as the reception sequence number is sent to the data transmitting radio apparatus to request retransmission. The data transmission wireless device that has received Rej
Corresponding to the received sequence number included in the data I _1-5
(The poll bit is set to 1 in this example, so it waits for the RR signal from the data receiving wireless device), and waits for the reception of the response having the reception sequence number that matches the transmission state variable, When the same signal is received, transmission of the next data I is restarted.

Next, in FIG. 7, SRej (Select
ive Reject) procedure, and only the operation different from Rej will be described below.

In this SRej, if the data I _{1-3 in} which the poll bit p is not set is damaged and the next data I _1-4 is normally received, the data receiving wireless terminal transmits the data I _1-3.
In order to request the retransmission of only _1-3, the SREJ carrying the parameter indicating the reception number of the damaged data is sent to the data transmission wireless device. Upon receiving this signal, the data transmission wireless device immediately receives the SRej after transmitting the current transmission data.
The data I indicated by is retransmitted, and then the process returns to the operation of transmitting the data I according to the transmission sequence number.

However, in the above-mentioned conventional example, although the damage of the data due to the extreme deterioration of the radio line due to the influence of the interference wave or the like is less problematic when it is recovered in a short period, the deterioration of the line lasts several seconds or more. In the subsequent case, as shown in FIG. 8, the retransmission procedure is repeated until the maximum number of times is exceeded, and then the data link is disconnected once.

However, if the re-sending operation is repeated the maximum number of times and then the link is disconnected and the link is reestablished,
Not only does this lead to a decrease in throughput, but because radio waves continue to be sent in an uncommunicable state, the radio wave propagation state deteriorates further, affecting other systems as well. It becomes a problem.

In the retransmission procedure, in a system having a Rej-only retransmission procedure, the data transmission wireless device is
Since data is sent continuously up to the outstanding number (which indicates the maximum value at which data can be sent without receiving confirmation of receipt), in a system that performs time-division two-way communication, data is sent when the number of times data is sent is small. If the data is damaged, the data from the damaged data to the outstanding number is discarded by the data receiving wireless device, so that the throughput is reduced and the occupied time of the radio wave is wasted as in the above. There is a problem.

Further, in the system in which SRej and Rej are combined, the number of outstandings can be increased and the reduction in throughput can be improved, but the protocol control becomes complicated and the number of outstandings is increased, so Since the storage capacity of the system becomes large, it leads to the expansion of the system hardware, making it difficult to miniaturize, and further increasing the cost.

Therefore, in the present embodiment, at the time of data transmission, direct wave removing means for removing the direct wave of the transmission wave to the receiving antenna and the level of the radio wave in the transmission frequency band are detected to destroy the transmission data. A judging means is provided for judging a channel collision situation, and a judging means for judging a received data destruction situation according to a synchronization holding state and a data bit error situation at the time of data reception. Then, by providing a protocol for temporarily suspending and resuming data communication according to the state of radio waves in the frequency band determined by these determination means, it is possible to use space and protocol until the propagation state of radio waves in space is recovered. Thus, it becomes possible to stop the data communication, eliminate unnecessary retransmission request operation, and avoid inducing disconnection of the data link after the retransmission operation, thus improving the throughput. In addition, since the state can be recognized in real time during data communication, the throughput can be improved by the simple control as in the case of SRej, the transmission data buffer capacity can be saved, and the device can be downsized and the cost can be reduced. The effect that it can be achieved is obtained. In addition, when communication is not possible, transmission / reception of data is stopped and output of radio waves is stopped, so that this system does not adversely affect other systems, and effective use of radio waves can be achieved.

Next, the third embodiment will be concretely described.

FIG. 9 is a block diagram for explaining the functional elements of the third embodiment.

The device of the third embodiment is, as shown in the drawing,
A wireless protocol control circuit 1 for controlling a protocol in a wireless section, a transmission circuit 2 for executing data transmission, and a transmission state detection circuit 3 for detecting a state at the time of data transmission.
And a transmission antenna 4, a reception antenna 5, a transmission control circuit 6 for judging the transmission state and notifying the transmission circuit and the radio protocol control circuit 1 of the state, and synchronization acquisition, holding, and bit error correction. Reception demodulation circuit 7
And a reception state control circuit 8 for determining the reception state at the time of data reception and notifying the radio protocol control circuit 1 of the reception state.
Have and.

FIG. 10 is a block diagram showing the structure of a more concrete transmitting / receiving circuit of the third embodiment.

The transmission circuit 2 is generated by a code generator 2-a for generating a code for spreading the spectrum, an oscillator 2-b for generating a carrier frequency, and a code generator 2-a. A mixer 2-c for modulating a carrier with a spread code, an amplifier 2-d for amplifying a spread signal to a transmission power level, and a bandpass filter (hereinafter, referred to as B for passing a transmission signal band frequency).
2-e).

Further, the transmission state detection circuit 3 has a mixer 3-a for modulating the carrier by the spread code generated by the code generator 2-a, and a phase opposite to the transmission signal input from the receiving antenna 5. 3-b for amplifying the signal of 1 to the same level, BPF 3-c for passing the transmission signal band frequency, and for removing the transmission signal (that is, direct wave) directly input to the receiving antenna 5. And a cancel circuit 3-1. Note that the cancel circuit 3-1 is configured to cancel the two-phase PSK in order to simplify the description in this embodiment, but it can also be applied to other modulation methods (for example, FSK).

The cancel circuit 3-1 includes delay circuits 3-d and 3-e for adjusting the phases of the anti-phase spread signal for removing the direct wave and the received direct spread signal, and the delay circuits 3 respectively.
-D, amplifier 3 for amplifying signals from 3-e 3-
It has f and 3-g, and an adder 3-h for adding each signal. Note that, as shown in FIG. 11, the received direct wave 4-a of the local station transmission signal is transmitted by the transmission antenna 4 and the reception antenna 5.
Since the position of is fixed, the amount of delay in space propagation is always constant, and each delay circuit 3 is based on this constant amount of delay.
-D and 3-e are set.

Further, the transmission state detection circuit 3 is provided with a SAW convolver 3-k for correlating signals (including reflected waves of the transmission signal) other than the direct wave and the reference signal, and for producing the reference signal. A carrier generating oscillator 3-i, a mixer 3-j for modulating a carrier by the reference code generated by the code generator 2-a, and a detection circuit 3-for detecting the output of the convolver 3-k. l and this detection circuit 3-l
And a level determination circuit 3-m for generating a status signal from the output level of.

Further, the reception demodulation circuit 7 has a BPF 7-a for removing frequencies other than the reception signal band frequency.
And an AGC amplifier 7-b for keeping the reception level constant.
A synchronization capturing circuit 7-c for capturing the initial synchronization from the received wave, a synchronization holding circuit 7-d for retaining the synchronization captured by the synchronization capturing circuit 7-c, and a bit error correction circuit. And the demodulation circuit 7-e included therein.

FIG. 11 is a schematic perspective view showing the propagation state of radio waves in the communication system of this embodiment.

In FIG. 11, two spread spectrum communication devices 9 and 10 each having the function according to the present invention,
It is assumed that the spread spectrum communication device 11 of another station exists.

In FIG. 11, a signal 4-b is a reflected wave of the own station transmission signal, and a signal 4-c is a reflected wave of the other station transmission signal transmitted from the spread spectrum communication device 11 of the other station. 4-d is a direct wave of the transmission signal of another station, and signal 4-e is
A narrowband interference wave of another station 4-f (for example, a high-power narrowband signal transmitted by an aeronautical radar) is shown.

FIG. 12 to FIG. 15 are waveform charts showing an example of the detected waveforms in the transmission state band and the radio wave state in the transmission frequency band in the transmission state.

That is, FIGS. 12 to 15 show signal states after the canceling circuit 3-1 cancels all the reception direct waves 4-a of the local station transmission signal, and FIG.
Indicates the case where only the reflected wave 4-b of the local station transmission signal exists. 13 and 14 show a spread wave 4-b of a transmission signal and a spread spectrum signal of another station using the same code and the same frequency band (for example, outputs 4-c and 4-d of the spread spectrum communication device 11). ) Is present, and FIG. 15 shows a case where a reflected wave 4-b of the transmission signal and a narrowband interference wave 4-e (for example, an aerial radar signal) are present.

The actual operation will be described below. Figure 1
FIG. 6 is a state transition diagram showing an example of data communication control.

First, the data transmission operation will be described. The transmission state control circuit 6 judges the state signal of the transmission state detection circuit 3 and determines the propagation state of the space (state of the wireless line).
If it is good, TXO for the radio protocol control circuit 1
Sends a K signal. If the wireless line condition is bad here (for example, when the spread spectrum communication device 11 of another station is communicating using the same frequency and the same code, or the wireless line is deteriorated by the high output narrow band interference wave 4-e). If it occurs), a TXNG signal is sent to the wireless protocol control circuit 1 to keep the transmission amplifier 2-d off. Then, when the wireless link section is restored, a TXOK signal is sent out, and a transmission permission is issued.

The radio protocol control circuit 1 receives the TXOK signal, and if it is the data to be transmitted, the code generator 2
-Send the transmission data to a. When the data is 1, the code generator 2-a receiving this data outputs the spread code (1 cycle) block as it is to the mixer 2-c,
When the data is 0, the spread code block is inverted (inverted) and output to the mixer 2-c. At the same time, an inverted spread code is output for the data 1 and a non-inverted spread code is output for the data 0 to the mixer 3-a.

In the mixers 3-a and 2-c, the carrier signal generated from the oscillator 2-b is secondarily modulated by the spread code modulated by the transmission data, and each amplifier 2-
b, 3-b.

The output (spread signal) of the amplifier 2-b whose frequency spectrum is spread and amplified by this modulation operation.
Has its harmonic components cut off by the BPF 2-e, and is transmitted as a transmission signal 4-a from the transmission antenna.

The transmission signal 4-a includes a signal such as a reflected wave in space propagation, and is received by the receiving antenna 5 of its own station as a received wave. The received signal is a BPF3-c having the same pass band as the BPF2-e for transmission,
The BPF 7-a having different pass bands separates the received wave for state detection and the received wave for data reception.

The received wave for detecting the state, that is, the received wave including the reflected wave 4-b of the transmission signal of its own station, passes through the BPF 3-c, and the phase matching delay circuit 3-d of the cancel circuit 3-1. Entered in.

The canceling spread signal modulated in anti-phase by the mixer 3-a is adjusted by the amplifier 3-b to the level of the received direct wave 4-a of the transmission signal of its own station, and then sent to the delay circuit 3-e. Is entered. These two delay circuits 3-
The signals whose phases are matched by b and 3-e are amplified by amplifiers 3-f and 3-g, respectively, and then added by an adder 3-h.
A signal 12-f that has been input to the above and in which only the received direct wave 4-a component of the local station transmission signal has been canceled is obtained.

This direct wave cancellation signal 12-f is S
It is input to one input terminal of the AW convolver 3-k. S
At the other input end of the AW convolver 3-k, a code obtained by inverting the spread code for transmission from the code generator 2-a on the time axis is used as a carrier generated by the transmitter 3-i and the mixer 3 The reference spreading code modulated by -j is input. Then, the SAW convolver 3-k correlates the reference spreading code with the direct wave cancellation signal 12-f.

The correlation output of the SAW convolver 3-k has its envelope detected by the detection circuit 3-1 and then the level determination circuit 3-composed of a plurality of comparators.
Input to m. In the level determination circuit 3-m, the voltage 12 set at the receivable limit set in each comparator is set.
-A is compared with the output detection voltage of the SAW convolver 3-k (a voltage that is not affected by the noise level due to reception of only the reflected wave 4-b) 12-b, and a level determination indicating the comparison result is made. The signal is output to the transmission state control circuit 6.
The transmission state control circuit 6, which receives the level determination signal, recognizes the transmission state based on the pattern of the signal. The recognition of the transmission state will be described below with an example.

First, the direct wave 4- of the transmission signal of the own station of FIG.
In the case where only a and the reflected wave 4-b of the local station transmission signal exist, the output signal of the cancel circuit 3-1 is as shown in FIG.
As shown in 13-d of No. 2, a sharp peak is output only when the output of the SAW convolver 3-k matches the reference spreading code. The envelope of the output of the SAW convolver 3-k is detected by the detection circuit 3-1 and compared with the comparison voltages 12-a and 12-b set by the level determination circuit 3-m, and the comparison signal 13-c. , 13-d are output to the transmission state control circuit 6.

Here, the transmission state control circuit 6 measures the pulse periods of the comparison signals 13-c and 13-d.
Then, when the same period as the spread code period is obtained for a certain period, it is determined that the transmission is normally performed. Further, in the case where there is no reflected wave 4-b of the local station transmission signal, the comparison signals 13-c and 13-d cannot be obtained. However, also in this case, similarly to the above, it is determined that the transmission is normally performed by detecting that the comparison signals 13-c and 13-d are not present for a certain period. This is because when there are signals 4-c and 4-d from other stations with the same code and the same frequency, unless the transmission data are all reversed, the SAW
This is because the output of the convolver 3-k will not disappear.

When it is judged that the transmission state is normal,
The transmission state control circuit 6 sends a T to the wireless protocol circuit 1.
Continue sending the XOK signal.

Further, as shown in FIG. 13, when there is a signal from another station 4-f at the same timing and the same code as the reflected reception wave 4-b of the own station transmission signal, the SAW convolver is used. The output 14-a of 3-k has a state in which the phase is inverted and canceled by the data of each spread signal. For this reason, the detection signal 14-b is in a state where it is not applied to either of the comparison voltages 12-a and 12-b, and the comparison signal 14-c sent to the transmission state control circuit 6
14-d does not come every spread code cycle, and by detecting this missing signal, it is possible to recognize a transmission collision with another station 4-f.

Further, when there is a signal from another station 4-f having the same code and the same frequency at a timing shifted by one spread code chip from the reflected reception wave 4-b of the own station transmission signal as shown in FIG. The output of the SAW convolver 3-k is 15
As shown in -a, peaks appear adjacently (basically, when performing communication in time division using the same code and the same frequency, carrier sensing is performed before outputting a transmission signal, This phenomenon cannot occur).

This peak is judged by the level judging circuit 3-m, and a plurality of pulses as shown in 15-c and 15-d are transmitted. The plurality of pulses are judged by the transmission state control circuit 6 and recognized as having interference, and at this time, the radio protocol control circuit 1 receives TXNG.
A signal is transmitted and an output off signal is output to the transmission amplifier 2-d.

Further, in FIG. 11, when there is a narrow-band interference wave 4-e in addition to the direct wave 4-a of the local station transmission signal, the cancellation circuit 3-1 causes the local station transmission signal of the local station transmission signal to be generated as described above. The direct wave 4-a is removed, and the narrow band interference wave 4-e is judged by the output of the SAW convolver 3-k.

That is, first, when the level of the narrowband interference wave 4-e is small, the noise level is slightly higher than the output 13-a of the SAW convolver 3-k shown in FIG. However, if the output of the SAW convolver 3-k is not at a noise level exceeding the receivable limit voltage 12-a, communication is possible, so that the transmission state control circuit 6 has deteriorated the transmission state. Recognize that.

Further, when the output of the narrow band interference wave 4-e is high as in the case of the aircraft radar, the canceling circuit 3-1 causes the direct wave 4-a of the transmission signal of its own station similarly to the above.
Even when the SA is removed, as shown in FIG.
The output 16-a of the W convolver 3-k has a considerably high noise level other than the correlation peak. Therefore, in this case, since the peak of the detection output 16-b exceeds many comparison voltages 12-a which set the receivable limit, the level determination circuit 3-m outputs a plurality of pulses as the determination signal 16-c. .. The transmission state control circuit 6 that has received the determination signal 16-c recognizes that transmission is impossible.

Further, even when the level of the inter-station interference wave other than the narrow band interference wave is high, the SAW convolver 3
Since the output of -k is the same, it is recognized that transmission is impossible. Also in this case, the transmission state control circuit 6 sends the T
The XNG signal is transmitted, and the transmission off signal is transmitted to the transmission amplifier 2-b.

As described above, the radio protocol control circuit 1 which receives the transmission status signals (TXOK, TXNG) from the transmission status control circuit 6 performs the following operation in response to the signal.

First, upon receiving TXOK, the radio protocol control circuit 1 sends the transmission data I to I _1-1 , as in the conventional case.
Send it out in order, such as I _1-2 . And the data I
_{When the} TXNG signal is received from the transmission state control circuit 6 during the transmission of _1-3 , the transmission of the data I _1-3 is suspended and the wireless line suspension signal is transmitted to the user interface (not shown). The user interface that receives this will put weight on the protocol.

Thereafter, the radio protocol control circuit 1 waits for the reception of the TXOK signal from the transmission state control circuit 6,
When this signal is received, the data I _1-3 whose transmission has been interrupted is transmitted, and then the normal data transmission sequence before interruption is returned.

Next, the data receiving operation will be described.

In the spread spectrum communication device 10 for receiving the data transmitted from the spread spectrum communication device 9, first, the data signal received from the receiving antenna 5 passes through the BPF 7-a which passes only the receiving band, and then the AGC.
It is input to the synchronization acquisition circuit 7-c, the synchronization holding circuit 7-d, and the demodulation circuit 7-e via the amplifier 7-b.

In the receiving circuit 7-1 that receives this signal, first, the synchronization acquisition circuit 7-c including a SAW convolver, a detection circuit, a counter and the like pulls initial synchronization from the received wave. Then, when the pull-in of synchronization is completed, the synchronization acquisition circuit 7-c outputs the timing of synchronization to the synchronization holding circuit 7-d, and at the same time, outputs the signal obtained by detecting the output of the SAW convolver to the synchronization holding circuit 7-d.

The synchronous holding circuit 7-d which receives this signal is DL
The clock and the code for despreading are sent to the demodulation circuit 7-e while maintaining synchronization by an L (delay lock loop) circuit or the like. As a result, the demodulation circuit 7-e performs the bit error correction after performing the despreading operation,
Received data is sent to the wireless protocol control circuit 1.

Next, the reception state is detected by the synchronization holding circuit 7-d and the demodulation circuit 7-e described above, and is determined by the reception state control circuit 8.

First, in the synchronization holding circuit 7-d, the detection signal sent from the synchronization acquisition circuit 7-c is determined by the same operation as the level determination circuit 3-m of the transmission state detection circuit 3 described above, and the reception state is determined. Output to the control circuit 8.

Upon receiving this signal, the reception state control circuit 8
Since the reception status is determined according to substantially the same criteria as the transmission status control circuit 6, only differences from the transmission status control circuit 6 will be described below.

The reception state control circuit 8 uses not only the output of the SAW convolver but also the data of the error correction circuit performed in the demodulation circuit 7-e. Since the error correction circuit can recognize the occurrence of the bit error, this error information is sent to the reception state control circuit 8.

Upon receiving the error information and the signal from the synchronization holding circuit 7-d, the reception state control circuit 8 first determines from the error information whether or not a burst error has occurred. And if there is a burst error,
The same determination as the transmission state control circuit 6 is performed by the synchronization holding circuit 7-d
The signal from is used. Then, similarly to the determination of the transmission state, it is determined that the reception is impossible only when the deterioration of the wireless line state is recognized, and RXNG is sent to the wireless protocol control circuit 1. This signal will continue to be sent until the reception is improved.

Upon receiving the RXNG signal, the protocol control circuit 1 discards the data I _1-3 currently being received, interrupts the reception operation, and sends a radio line interruption signal to the user interface. The user interface that receives this will put weight on the protocol.
This state is maintained until the reception state is improved (RXOK is received).

In the third embodiment, since the SAW convolver is used as the correlator of the initial synchronization acquisition means of the radio line state detecting and receiving circuit, it is possible to change the spreading code for reference in order. The communication status of the station can be monitored. As a result, in the spread spectrum communication device using the spread code division multiplexing method, in the case of an application in which the spread code allocation is changed for each communication, the spread code communication system can also be used as the empty code detection circuit. Further, by using a matched filter instead of the SAW convolver, it becomes possible to reduce the number of parts and realize the function shown in the third embodiment.

Next, a fourth embodiment of the present invention will be described.

In the fourth embodiment, when the power supply of the communication device is turned on, the sending condition of the interfering wave is detected, and the period and time of the interfering wave having the periodicity are detected, and the periodic interfering wave is detected. In addition, the transmission is temporarily stopped, and the transmission is restored when the interfering wave is no longer detected.
The basic structure of the apparatus is the same as that of the third embodiment shown in FIGS.
The same as in No. 1 above, and the signal status and the like will be described with reference to FIGS.

FIG. 17 is a state transition diagram showing an example of data communication control in the fourth embodiment. Note that in FIG. 17, since the operation is unrelated to the above-described poll bit p, each data is represented as an I frame.

First, when the data communication device 9 in FIG. 11 is powered on, the transmission state control circuit 6
An internal timer measures the detection time of the interference wave output by the transmission state detection circuit 3 and the time when the interference wave is not detected for a certain period of time, and measures the cycle and the generation time of the interference wave such as an aviation radar signal. To do. If no interfering wave is detected at this time, it is determined that there is no periodic interfering wave, and the interfering wave detection operation ends.

After the interference wave period detection operation is completed, when there is a data communication request from the wireless protocol control circuit 1, the transmission state control circuit 6 uses the time when there is no interference wave as a communication permission signal to control the wireless protocol. After the signal is applied to the circuit 1, the transmission state monitoring operation is started until the aforementioned interfering wave detection time comes.

Upon receiving the communication permission signal, the wireless protocol control circuit 1 shifts to the link connection operation in the wireless section, performs the link connection, and then performs the data communication operation. When the interfering wave detection time is notified by the internal timer during the data communication operation, the transmission state control circuit 6 sends a communication stop signal to the wireless protocol control circuit 1 and shifts to the interfering wave detection operation. In this interfering wave detection operation, the difference between the output of the transmission state detection circuit 3 and the internal detection time is detected as in the case of turning on the power, and the deviation of this state is corrected.

Upon receiving the communication stop signal, the wireless protocol control circuit 1 temporarily suspends the data transmission at the time of data transmission, and sets the address of the data buffer to retransmit the interrupted transmission data. Fix and wait for communication permission signal.

When the communication stop signal is received in the reception standby state, the reception confirmation timer is temporarily stopped, the same communication permission signal as described above is waited for, and when the permission signal is received,
Reactivate the acknowledgment timer.

When a communication stop signal is received during data reception, the data currently being received is discarded, and the reception operation is restarted when the communication permission signal is obtained.

Also in the fourth embodiment, the operation of monitoring the communication state at the time of data communication and temporarily suspending the transmission or reception when an excessive interference wave is received is the same as the third embodiment. The description is omitted because it is the same as.

Also in the fourth embodiment, in the spread spectrum communication device using the spread code division multiplexing method, it is also used as a vacant code detection circuit in the case of an application in which the spread code allocation is changed for each communication. Is possible. In addition, by using a matched filter instead of the SAW convolver, it is possible to reduce the number of parts and realize the function shown in the fourth embodiment.

Further, in the above third and fourth embodiments, the spread spectrum communication device which monitors the transmission state and the reception state and temporarily suspends the transmission and the reception when the excessive interference wave is received is described. However, as the fifth embodiment of the present invention, it is also possible to configure it as an apparatus which exclusively monitors the transmission state.

FIG. 18 is a block diagram showing the structure of such a transmission state detecting device.

As shown in the figure, the structure shown in the fifth embodiment is different from the structure described in the above-mentioned third and fourth embodiments (FIG. 2) in the radio protocol control circuit 1, the reception demodulation circuit 7, and the reception state control. Since the circuit 8 is omitted and the other elements are common, the same reference numerals are given and the individual description is omitted.

Even in such a device, the state at the time of data transmission can be detected by the same processing as in the third and fourth embodiments.

FIG. 19 is a block diagram showing the configuration of a transmission state detecting apparatus provided with a matched filter 3-n instead of the SAW convolver 3-k as the sixth embodiment of the present invention.

Also in this device, the transmission state in the spread spectrum communication device can be detected as in the fifth embodiment.

Also, in the fifth and sixth embodiments described above, in the spread spectrum communication apparatus using the spread code division multiplexing method, as an empty code detection circuit in the case of an application in which the spread code allocation is changed for each communication. It becomes possible to share.

Next, a seventh embodiment of the present invention will be described.

The seventh embodiment is provided with a means for increasing or decreasing the outstanding number in the wireless section according to the number of I-frame retransmissions during the data transmission / reception operation until the propagation condition of the radio wave in the space is recovered. In the interval, the number of outstandings is minimized and unnecessary retransmission operation is omitted. This makes it easy to control SR
It is possible to obtain the throughput improvement similar to that of ej, and further, it is possible to save the transmission data buffer capacity, and to reduce the size and cost of the device.

FIG. 20 is a state transition diagram showing a data communication control example and an outstanding number variable operation example in the seventh embodiment, and FIG. 21 is a flow chart showing an outstanding number control procedure.

In FIG. 20, the error counter (EC)
21 is a counter in a wireless section control circuit (not shown), and as shown in FIG.
It is incremented (+1) every 1) (S2), and is cleared when it reaches a preset value (10 in this embodiment) (S3, S4).

Further, this error counter (EC) is I
Every time a frame is normally transmitted / received (S1), it is decremented (-1) (S10), and the minimum value 0 is taken (S7).

On the other hand, the outstanding number counter (OC) is provided in the radio section control circuit like the error counter (EC), and is a counter for counting the number of outstanding numbers. An I frame without an acknowledgment request (Pbit = 0) is transmitted.

This outstanding number counter (O
The value of C) is decremented (-1) (S6) when the value of the error counter (EC) reaches the set value 10 in the retransmission operation of the I frame (S1), and takes the minimum value of 1 (S5).

When normal I-frame transmission is performed and the value of the error counter (EC) is 0 (S7), increment (+1) is performed (S9), and the maximum is 7 (modulo 8). Maximum value of 1 when modulo 128
The value of 27) is taken (S8). The specific operation will be described below.

First, in FIG. 20, when the value of the error counter (EC) is 0 and the value of the outstanding number counter (OC) is 5, the I-frame I with Pbit = 0 from the wireless section control circuit. _{1-1 to} I _1-4 ,
The I frame I _1-5 having Pbit = 1 (confirmation request bit) is transmitted.

Here, as shown in FIG. 20, since the received frame data of I _1-3 is corrupted in the data receiving radio apparatus, the I frames of I _1-4 and I _1-5 are discarded, I _1-3
Sends out a resend request Rej signal. The data transmission wireless device that has received this, increments the value of the error counter (EC) by +1 by the internal wireless section control device, and transmits again from I _1-3 .

Next, due to this retransmission, the I frames I _1-3 and I _1-4 are normally received, but since the I frames I _1-5 have been damaged again, the retransmission request Rej signal is again received. Is sent. The data transmission wireless device which has received this, similarly to the above, increments the value of the error counter (EC) by +1 by the internal wireless section control device, and transmits again from I _1-4 .

Then, the value of the error counter (EC) is 1
When it becomes 0, the wireless section control circuit looks at the value of the outstanding number counter (OC), and if it is not 1, it becomes -1.
After that, I frame transmission is performed again.

When the value of the outstanding number counter (OC) becomes 1, all the I frames sent from the wireless section control circuit are set to 1 in Pbit. Then, the data receiving wireless device that has received the I frame of Pbit = 1 sends out the reception confirmation signal RR if the data is normally received. The data transmission wireless device receives an error counter (E
The value of C) is detected, and if it is not 0, the error counter (EC) is decremented by 1 and the I frame is transmitted again.

When the normal communication operation is repeated, the value of the error counter (EC) is 0, and the reception confirmation signal RR is received, the wireless section control circuit adds 1 to the outstanding number counter (OC). , After transmitting the I frame with Pbit = 0, which is one less than the added value, Pb
I frame of it = 1 is continuously transmitted, and reception confirmation signal R
Wait for R.

In the seventh embodiment, the upper limit setting value of the error counter (EC) is fixed, but it is also possible to change this value depending on the occurrence status of the retransmission request. Also, by monitoring the outstanding number, for example, when the retransmission request is continuously received while the outstanding number is fixed to 1, it is possible to recognize the rapid deterioration of the radio wave propagation state. In the above, it is possible to add a protocol such as interrupting the one-time communication when the propagation situation is severely deteriorated. This has the advantage that this system does not adversely affect other systems and effective use of radio waves can be achieved.

[0118]

As described above, according to the present invention,
When the received power in the band where a narrow band interference wave is generated is detected, and when this power exceeds a prescribed value, an extremely large level interference wave is input by performing despreading after removing the band signal. In this case, it is possible to remove the interfering wave and secure stable communication quality.

Further, according to the present invention, the transmission state and the reception state of data are monitored and the interruption of communication or the like is controlled according to the propagation state of radio waves in the communication frequency band. It is also possible to avoid the occurrence of the data link disconnection after the retransmission operation, and to improve the throughput.

Further, according to the present invention, means for increasing or decreasing the outstanding number indicating the maximum value at which packet data can be transmitted without receiving confirmation of reception according to the propagation state of the wireless section, and setting of this outstanding number. By providing the means for transmitting the packet data according to the value, it becomes possible to control the number of reception confirmation request packets according to the propagation condition of the radio wave in the space, and it is possible to reduce the total number of I frames to be transmitted according to the retransmission request. It is possible to improve overall throughput by adding simple software.

[Brief description of drawings]

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

FIG. 2 is a waveform diagram showing a signal waveform at the time of reception in a conventional spread spectrum communication device.

FIG. 3 is a waveform diagram showing a signal waveform in the case where an interference wave exceeding the interference exclusion capability is input in the conventional spread spectrum communication device.

FIG. 4 is a waveform diagram showing a signal waveform when an interference wave exceeding the interference rejection capability is input in the spread spectrum communication device of the first embodiment.

FIG. 5 is a block diagram showing a second embodiment of the present invention.

FIG. 6 HD in a conventional spread spectrum communication device
It is a state transition diagram which shows the example of the resending procedure in LC.

FIG. 7: HD in a conventional spread spectrum communication device
It is a state transition diagram which shows the example of the resending procedure in LC.

FIG. 8 is a state transition diagram showing a procedure of disconnecting a data link due to an influence of an interference wave or the like in a conventional spread spectrum communication device.

FIG. 9 is a block diagram illustrating functional elements of a third embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a transmission / reception circuit of the third embodiment.

FIG. 11 is a schematic perspective view showing a propagation state of radio waves in the communication system of the third embodiment.

FIG. 12 is a waveform diagram illustrating contents of data processing in the third embodiment.

FIG. 13 is a waveform diagram illustrating the contents of data processing in the third embodiment.

FIG. 14 is a waveform diagram illustrating the contents of data processing in the third embodiment.

FIG. 15 is a waveform diagram illustrating contents of data processing in the third embodiment.

FIG. 16 is a state transition diagram showing an example of data communication control in the third embodiment.

FIG. 17 is a state transition diagram showing an example of data communication control according to the fourth embodiment of the present invention.

FIG. 18 is a block diagram showing a transmission state detection device according to a fifth exemplary embodiment of the present invention.

FIG. 19 is a block diagram showing a transmission state detection device in a sixth exemplary embodiment of the present invention.

FIG. 20 is a state transition diagram showing a data communication control example and an outstanding number variable operation example in the seventh embodiment of the present invention.

FIG. 21 is a flow chart showing a control procedure of the outstanding number in the seventh embodiment.

[Explanation of symbols]

 101 ... Receiving antenna, 102, 105 ... BPF, 103 ... RF amplifier, 104 ... Delay circuit, 106 ... Detection circuit, 107 ... Judgment circuit, 108 ... Switch, 109 ... Adder, 110 ... Demodulator.

Claims (5)

[Claims] 1. A detection means for detecting a reception power of a narrow band interference wave occurring in a predetermined frequency band; a determination for determining that an excessive interference wave is mixed when the reception power exceeds a predetermined value. A spread spectrum communication device comprising: means; signal removing means for removing the predetermined frequency band signal only when it is determined that the excessive interference wave is mixed. 2. A direct wave removing means for removing a direct wave of a local station transmission signal received by a local station receiving antenna during data communication; a level of a radio wave within a transmission frequency band is detected, and based on the detected state. Determining means for determining transmission data destruction and channel collision status by means; determination means for determining reception data destruction status by synchronization holding state and data bit error status during data reception; And a communication control unit that controls interruption and resumption of communication based on the above. 3. An interfering wave detecting means for detecting an interfering wave generation status; a cycle setting means for setting an interfering wave cycle based on the detecting status of the interfering wave detecting means; Correction means for correcting the cycle error of the interference wave based on the cycle of the interference wave and the detection status of the interference wave thereafter; interruption of communication corresponding to the cycle when a periodic interference wave is detected, Communication control means for controlling resumption;
A spread spectrum communication device having: 4. A direct wave blocking means for blocking a direct wave of a transmission spread signal transmitted from a local station transmitting antenna and received from a local station receiving antenna; receiving a received wave other than the direct wave,
Correlation means for correlating with the transmission spread code; detection means for detecting a correlation output and an interfering wave component; determination means for determining a radio wave propagation state at the time of transmission from a detection signal of this detection means Transmission state detection device. 5. Means for increasing or decreasing a constant indicating a maximum value capable of transmitting packet data without receiving confirmation of reception in accordance with a propagation state of a wireless section in accordance with a data transmission / reception state; A means for transmitting packet data; and a wireless communication device.