JP4720247B2 - Receiver, receiving method thereof, communication system, and flying object - Google Patents

Description

  The present invention relates to a receiver, a receiving method thereof, a communication system, and a flying object, and in particular, assigns different delay times to branched transmission data, spreads these delay outputs using different spreading codes, and synthesizes these spread outputs. The present invention relates to a receiver that receives signals transmitted in this manner, a receiving method thereof, a communication system, and a flying object.

  FIG. 6 is a view showing the appearance of the aircraft. In FIG. 6, an aircraft 1 is provided with an upper antenna 2 at the top of the fuselage and a lower antenna 3 at the bottom of the fuselage. Perform spread communication.

  In communication between the ground station and the aircraft 1, the sea surface reflected wave has a smaller delay time than the main signal wave, and generally causes fading. This means that the main signal wave and the reflected wave are synthesized with opposite phases, and the received signal disappears. Normally, since the upper antenna 2 and the lower antenna 3 provided on the airframe have independent phase relationships, the probability of simultaneous disconnection is small, and the higher reception quality can be selected to obtain the effect of spatial diversity.

  Next, FIG. 7 shows the configuration of the spread spectrum diversity transmitter / receiver described in Patent Document 1. In FIG. 7, transmission data is encoded by the error correction encoder 101 in the transmitter. This is N-branched and passed through delay elements 102-1 to 102-N-1. The branch 1 is not delayed, and the second branch receives a delay of τ2 by the delay element 102-1, and the Nth branch receives a delay of τN by the delay element 102-N-1. Here, the delay times τ2, τ3,..., ΤN are all different. The interleaving circuits 103-1 to 103-N in the next stage perform interleaving processing. Although it is possible to change the interleaving cycle for each branch and to set the same cycle for all branches, it is assumed here that the interleaving cycle between the branches is the same. The outputs of the interleave circuits 103-1 to 103-N are primarily modulated by the modulators 104-1 to 104-N. N-branch modulated waves are spread by the spread spectrum circuits 105-1 to 105-N. The spreading codes used here are different from each other, and are encoded and multiplexed by the synthesis circuit 106 and transmitted by the transmitter 107 and the transmission antenna 108.

  In the receiver, the received wave of the receiver 110 is N-branched by the branch circuit 111 and despread by the spectrum despreading circuits 112-1 to 112 -N. Here, since the signal is despread by the same spreading code as that of the transmitter, the coded and multiplexed modulated wave is separated and extracted for each branch. The demodulators 113-1 to 113-N at the next stage demodulate the primary modulation on the transmission side. The data signal determined by the demodulator is deinterleaved by the deinterleave circuits 114-1 to 114-N, and further delayed by the delay elements 115-1 to 115-N so as to absorb the delay difference given on the transmission side. After the adjustment, the majority decision judgment circuit 116 receives the majority decision. The output of the circuit 116 is finally subjected to error correction by an error correction decoder 117.

  The transceiver shown in FIG. 7 not only simply randomizes burst errors due to instantaneous interruption due to multipath fading or the like by interleaving, but also randomizes the effects of burst errors between diversity branches by delay difference processing, Random errors are suppressed using diversity branch by majority decision processing. This operation is time diversity, and the majority decision is equivalent to diversity combining or diversity switching combining. Accordingly, in spread spectrum communication, diversity reception by coding multiplexing can be performed without using space diversity or frequency diversity by a fixed plurality of antennas or adaptive arrays.

Japanese Patent No. 2778498

  In the aircraft shown in FIG. 6, if there is a correlation between the antennas 2 and 3, fading between the branches is similar and both are likely to be momentary interruptions. In this case, switching between branches based on the reception quality becomes difficult, and it becomes difficult to obtain the effect of space diversity.

  On the other hand, the transmitter / receiver shown in FIG. 7 enables diversity reception without using a plurality of antennas. However, in the case of an aircraft, it has high mobility and is accompanied by a severe attitude change. Even if the transmitter / receiver shown in FIG. 7 is applied to an aircraft with high mobility and a severe attitude change, it is difficult to obtain the effect sufficiently.

  An object of the present invention is to provide a receiver capable of effectively performing diversity reception even when there is a correlation between antennas in a flying object with high mobility and a severe attitude change, a receiving method thereof, a communication system, and a flying object It is to be.

The receiver according to the present invention is a receiver that gives different delay times to the branched transmission data, spreads these delay outputs using different spreading codes, combines these spread outputs, and receives the transmitted signal. Then, for each of the plurality of antennas, a plurality of branch signals corresponding to the number of the different spreading codes received and branched through the antennas are despread using the different spreading codes. despreading means, a delay means for absorbing delay difference given to the transmitted data giving delay time, respectively it to the output of said despreading means, switching to selectively output one of an output of said delay means Means.

Another receiver according to the present invention branches transmission data subjected to error correction coding and interleaving , gives different delay times to the branched transmission data, and spreads these delay outputs using different spreading codes. A receiver for combining these spread outputs and receiving a transmitted signal, wherein each of the plurality of antennas and the number of different spread codes received and branched via the antennas and de-interleaving means and despreading means for despreading using the different spreading codes a plurality of the branch signal, the relative output of the despreading means for outputting by performing deinterleaving of the interleaving and inverse which corresponds to the de delay means for absorbing the delay difference given to the transmitted data giving delay time, respectively it to the output of the interleaving means, the delay means It characterized in that it comprises error correction decoding means for performing error correction decoding with respect to power, and a switching means for selecting and outputting one of the output of said error correction decoding means.

The receiving method according to the present invention provides different delay times to the branched transmission data, spreads these delay outputs using different spreading codes, combines these spread outputs, and receives the transmitted signal. A reception method, wherein for each of a plurality of antennas of the receiver , a plurality of branch signals corresponding to the number of the different spreading codes received and branched through the antenna are despread using the different spreading codes. despreading steps of: a delay step for absorbing the delay difference given to the transmitted data by applying the inverse spread delay time, respectively it despreading output by step, one of the delayed output by said delay step And a switching step for selective output.

Another receiving method according to the present invention branches transmission data subjected to error correction coding and interleaving , gives different delay times to the branched transmission data, and spreads these delay outputs using different spreading codes. A reception method for a receiver that receives a signal transmitted by combining these spread outputs, and for each of a plurality of antennas of the receiver, each of the different spread codes received and branched via the antenna A despreading step for despreading a plurality of branch signals corresponding to the number using the different spreading codes, a deinterleaving step for performing deinterleaving reverse to the interleaving on the despreading output by the despreading step, delay to absorb the delay difference given to the transmitted data to the output by the interleaving step gives delay time, respectively it And steps, characterized in that it comprises error correction decoding step of performing error correction decoding with respect to the delay output by the delay step, and a switching step for selecting and outputting one of the output by the error correction decoding step.

  The receiver is provided on a flying object, and the plurality of antennas are an upper antenna provided on an upper part of the aircraft and a lower antenna provided on a lower part of the aircraft.

  The flying object according to the present invention includes the receiver. The communication system according to the present invention includes the receiver.

  Each of the branched transmission data is given different delay times, these delay outputs are spread using different spreading codes, and the receivers that receive the signals transmitted by combining these spread outputs are sent via a plurality of antennas. The inter-branch timing is synchronized by absorbing the delay difference between the branches by the delay means after despreading the received branch signal. As a result, even when there is a correlation between the antennas, it is possible to avoid the instantaneous interruption of the signal between the branches, and the effect of space diversity can be obtained.

  According to the present invention, in a receiver that receives different signals by giving different delay times to the branched transmission data, spreading these delay outputs using different spreading codes, and combining these spread outputs. Branch signals received via a plurality of antennas of the receiver are despread using the different spreading codes, different delay times are given to these despread outputs, and the delay difference given to the transmission data is absorbed, Since any one of these delayed outputs is selectively output, it is possible to effectively receive diversity reception even if there is a correlation between antennas in a flying object with high mobility and a severe attitude change. .

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

  FIG. 1 is a diagram showing the configuration of a spread spectrum communication system according to a first embodiment of the present invention. In the spread spectrum communication system shown in FIG. 1, the transmitter includes a delay unit 11, spreading units 13-1 and 13-2, a combining unit 14, and an antenna 15. Provided.

  Further, the receiver includes antennas 16-1 and 16-2, despreading units 17-1 and 17-2, a delay unit 19, and a switching unit 20, for example, in the aircraft 1 shown in FIG. Provided. In this case, the antennas 16-1 and 16-2 correspond to the upper antenna 2 and the lower antenna 3 in FIG.

  In the transmitter, transmission data is branched into two, one is input to the spreading unit 13-1 and the other is input to the delay unit 11. That is, the transmission data input to the spreading unit 13-1 is not delayed, and the transmission data input to the delay unit 11 is input to the spreading unit 13-2 after being delayed by τ by the delay unit 11. Note that a delay unit may be provided in the preceding stage of the diffusion unit 13-1 to give a delay time different from τ.

  The spreading unit 13-1 performs spread modulation on the input data using a spreading code (A code). The spreading unit 13-2 performs spreading modulation on the input data using a spreading code (B code). The A code and the B code are different spreading codes. The synthesizing circuit 14 synthesizes and encodes and multiplexes the outputs of the spreading sections 13-1 and 13-2, and transmits the resultant to the receiver provided in the aircraft via the antenna 15.

  In the receiver, the branch signal (A code branch signal) received by the antenna 16-1 is input to the despreading unit 17-1, and the branch signal (B code branch signal) received by the antenna 16-2 is despread. Input to the section 17-2. The despreading unit 17-1 performs despreading processing on the input signal using the same A code as the spreading code used in the spreading unit 13-1. The despreading unit 17-2 performs despreading processing on the input signal using the same B code as the spreading code used in the spreading unit 13-2.

  The output of the despreading unit 17-1 is input to the switching unit 20 via the delay unit 19, and the output of the despreading unit 17-2 is input to the switching unit 20 without passing through the delay unit. The delay time of the delay unit 19 is the same τ as that of the delay unit 11, and therefore the outputs of the despreading units 17-1 and 17-2 are delay-adjusted so as to absorb the delay difference given on the transmission side. Is input to the switching unit 20. The switching unit 20 selectively outputs any one of the input signals.

  FIG. 2 is a diagram showing the inter-branch timing relationship in the first embodiment of the present invention. As shown in FIG. 2, even if the A code branch and the B code branch are instantaneously interrupted simultaneously due to the fading of the correlation between the antennas (see the inter-branch timing relationship on the propagation path), one branch on the transmission side as described above. Is given to the other branch after despreading to absorb the delay difference τ between both branches, so that the reception levels of the A code branch signal and the B code branch signal are simultaneously It is avoided that the value falls below a predetermined instantaneous interruption definition value (see the inter-branch timing relationship at the input of the receiving side switching unit 20), and fading of inter-antenna correlation can be relieved by diversity switching (receiving side switching unit 20). See inter-branch timing relationship in output).

  In the example of the inter-branch timing relationship at the output of the receiving side switching unit 20 in FIG. 2, the switching unit 20 normally selects and outputs the A code branch signal, and the reception level is below the instantaneous interruption definition value. Selectively outputs the B code branch signal, and when the reception level of the A code branch signal again exceeds the instantaneous interruption definition value, the A code branch signal is selectively output again. The operation of the switching unit 20 is not limited to this. For example, a signal having a high reception level may be selected and output from the A code branch signal and the B code branch signal.

  FIG. 3 is a diagram showing the configuration of the spread spectrum communication system according to the second embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals. As shown in FIG. 3, in the second embodiment of the present invention, the transmitter has an FEC (Forward Error Correction) encoder 10 and interleave units 12-1 and 12-2, and the receiver is a deinterleave unit 18- 1 and 18-2 and the FEC decoder 21 is different from the first embodiment.

  In the transmitter, the transmission data is encoded by the FEC encoder 10 and then branched into two, and one is input to the interleaving unit 12-1 and the other is input to the interleaving unit 12-2 via the delay unit 11. Each of the interleaving units 12-1 and 12-2 performs an interleaving process on the input data and outputs the result to the spreading units 13-1 and 13-2.

  In the receiver, the outputs of the despreading units 17-1 and 17-2 are input to the deinterleaving units 18-1 and 18-2, and deinterleaving opposite to the interleaving in the transmitter is performed. The FEC decoder 21 performs error correction decoding on the output of the switching unit 20.

  As a result, in the second embodiment of the present invention, it is possible to further suppress bit errors than in the first embodiment, similar to the transceiver described in Patent Document 1.

  In FIG. 3, the FEC decoder 21 is provided in the subsequent stage of the switching unit 20, but instead of being provided in the subsequent stage of the switching unit 20, an FEC decoder is provided for each branch in the previous stage of the switching unit 20. May be. In this case, the switching unit 20 determines which branch has higher channel quality based on the error detection result of the A code branch signal and the B code branch signal, and compares the received levels of the signals with each other. You may make it switch together.

  FIG. 4 is a diagram showing the configuration of a spread spectrum communication system according to the third embodiment of the present invention, and the same parts as those in FIG. 3 are denoted by the same reference numerals. As shown in FIG. 4, in the third embodiment of the present invention, the configuration of the transmitter is the same as that of the second embodiment, but the configuration of the receiver is different.

  In the receiver, the signal received by the antenna 16-1 is branched into two, and the branched branch signals are input to the despreading units 17-1 and 17-2. The processing in the despreading units 17-1 and 17-2 and the deinterleave units 18-1 and 18-2 is the same as that in the second embodiment. The delay unit 19-1 corresponds to the delay unit 19 of FIG. 3, and the delay time is the same τ as the delay unit 11.

  In addition, the signal received by the antenna 16-2 is branched into two, and the branched branch signals are input to the despreading units 17-3 and 17-4. The processes of the despreading units 17-3 and 17-4, the deinterleave units 18-3 and 18-4, and the delay unit 19-2 are performed by the despreading units 17-1 and 17-2 and the deinterleave units 18-1 and 18-1. -2 and the processing of the delay unit 19-1.

  The switching unit 20 selectively outputs one of the two branch signals in the first and second embodiments, but selectively outputs one of these four branch signals in the present embodiment.

  Thus, in the third embodiment of the present invention, the diversity branch can be expanded quadruple without increasing the number of antennas.

  In FIG. 4, as described in the second embodiment, instead of providing the FEC decoder 21 in the subsequent stage of the switching unit 20, an FEC decoder is provided for each branch in the previous stage of the switching unit 20. May be.

  As described above, in the first to third embodiments of the present invention, a delay τ is given to one branch on the transmitting side, and a delay τ is given to the other branch after despreading on the receiving side, so that the delay difference between the two branches. τ is absorbed. The value of the delay τ can be determined by transmitting a training signal from the transmission side to the reception side in advance. FIG. 5 is a diagram for explaining a method of determining the value of the delay τ. In FIG. 5, a training signal generation unit 31, a delay τ determination unit 32, and a transmission / reception unit 33 are provided on the transmission side of the system, and a transmission / reception unit 41 and an error detection unit 42 are provided on the reception side. It has been.

  The training signal generated by the training signal generation unit 31 is wirelessly transmitted by the transmission / reception unit 33, and the error detection unit 42 performs error detection on the training signal received by the transmission / reception unit 41 on the reception side. It is notified to the transmission side via the transmission / reception unit 41 at which bit an error has occurred. The delay τ determination unit 32 on the transmission side determines the value of the delay τ according to the notified error detection result. The value of the determined delay τ is set in the delay unit in each embodiment. Therefore, for example, the delay τ can be varied by periodically performing the above operation.

It is a figure which shows the structure of the spread spectrum communication system by 1st Example of this invention. It is a figure which shows the timing relationship between the branches in 1st Example of this invention. It is a figure which shows the structure of the spread spectrum communication system by 2nd Example of this invention. It is a figure which shows the structure of the spread spectrum communication system by the 3rd Example of this invention. It is a figure for demonstrating the method of determining the value of delay (tau). It is a figure which shows the external appearance of an aircraft. It is a figure which shows the structure of the conventional spread spectrum diversity transmitter / receiver.

Explanation of symbols

10 FEC encoder
11, 19, 19-1, 19-2 delay unit
12-1, 12-2 Interleave part
13-1, 13-2 Diffusion part
14 Synthesizer
15, 16-1, 16-2 Antenna 17-1, 17-2, 17-3, 17-4 Despreading part 18-1, 18-2, 18-3, 18-4 Deinterleaving part
20 switching part
21 FEC decoder
31 Training signal generator
32 Delay τ decision unit
33, 41 Transceiver
42 Error detection unit

Claims (13)

A receiver which gives different delay times to branched transmission data, spreads these delay outputs using different spreading codes, combines these spread outputs and receives the transmitted signal,
Multiple antennas,
Despreading means for despreading a plurality of branch signals corresponding to the number of the different spreading codes received and branched via the antenna for each of the plurality of antennas using the different spreading codes;
Delay means for absorbing the delay difference given to the transmitted data which respectively give delay time to an output of said despreading means,
And a switching means for selectively outputting any one of the outputs of the delay means. 2. The receiver according to claim 1, wherein the switching means selectively outputs one of the outputs of the delay means based on the reception level of the branch signal . Branch transmission data that has been subjected to error correction coding and interleaving, give different delay times to the branched transmission data, spread these delay outputs using different spreading codes, synthesize these spread outputs, and transmit A receiver for receiving the transmitted signal,
Multiple antennas,
Despreading means for despreading a plurality of branch signals corresponding to the number of the different spreading codes received and branched via the antenna for each of the plurality of antennas using the different spreading codes;
Deinterleaving means for performing deinterleaving opposite to the interleaving for the output of the despreading means,
Delay means for giving a delay time to the output of the deinterleave means and absorbing the delay difference given to the transmission data;
Error correction decoding means for performing error correction decoding on the output of the delay means;
And a switching means for selectively outputting one of the outputs of the error correction decoding means . 4. The receiver according to claim 3 , wherein the switching means selectively outputs one of the outputs of the error correction decoding means based on the error detection result of the branch signal in addition to the reception level of the branch signal. . Provided flying object, wherein the plurality of antennas, the upper antenna provided on the body upper part of the projectile, the reception of any one of claims 1 to 4, characterized in that there between the lower antenna provided in the lower body Machine. A flying body comprising the receiver according to claim 1. A communication system comprising the receiver according to claim 1. The delay time is determined based on an error detection result of the training signal received from the transmission side by transmitting a training signal from the transmission side to the reception side of the communication system. The communication system described. A receiving method of a receiver that gives different delay times to branched transmission data, spreads these delay outputs using different spreading codes, and combines these spread outputs to receive a transmitted signal,
A despreading step for despreading a plurality of branch signals corresponding to the number of different spread codes received and branched via the antenna for each of the plurality of antennas of the receiver using the different spread codes;
A delay step for absorbing the delay difference given to the transmitted data giving delay time, respectively it despreading output by said despreading step,
And a switching step of selectively outputting any one of the delay outputs by the delay step. The reception method according to claim 9 , wherein the switching step selectively outputs one of the delayed outputs by the delay step based on the reception level of the branch signal . Branch transmission data that has been subjected to error correction coding and interleaving, give different delay times to the branched transmission data, spread these delay outputs using different spreading codes, synthesize these spread outputs, and transmit A receiving method for a receiver that receives a received signal,
A despreading step for despreading a plurality of branch signals corresponding to the number of different spread codes received and branched via the antenna for each of the plurality of antennas of the receiver using the different spread codes;
A deinterleaving step for performing deinterleaving opposite to the interleaving on the despread output by the despreading step;
A delay step of giving a delay time to each output by the deinterleaving step and absorbing a delay difference given to the transmission data;
An error correction decoding step for performing error correction decoding on the delayed output by the delay step;
And a switching step of selectively outputting any of the outputs of the error correction decoding step . 12. The receiving method according to claim 11, wherein the switching step selects and outputs one of outputs from the error correction decoding step based on an error detection result of the branch signal in addition to a reception level of the branch signal. . The receiver is provided projectile, wherein the plurality of antennas, an upper antenna provided on the body above the projectile, one of claims 9-12, characterized in that between the lower antenna provided in the lower body Or the receiving method.

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