Radio communication system

Abstract

To reduce a resource to be used for digital signal processing for cell call detection.SOLUTION: A cell call detection system includes radio equipment including: tone generators 51-1 to 51-4 that generate tones of frequencies f1, f2, f3, f4 to be used for a cell call of an own aircraft of 16 types of tones, respectively; multipliers 53-1 to 53-4 that multiply the tones of frequencies f1, f2, f3, f4 generated by the tone generators 51-1 to 51-4 by an AM demodulation signal demodulated from a received signal, respectively; and integrators 54-1 to 54-4 that integrate multiplication results by the multipliers 53-1 to 53-4, respectively. The cell call detection system detects a cell call for the own aircraft by determining the existence of the tones of frequencies f1, f2, f3, f4 using levels of integration results by the integrators 54-1 to 54-4, respectively.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a wireless communication system including a radio set that executes a self-call detection process. [Background technology]

[0002] Conventionally, various inventions have been proposed for reducing the burden on control terminals in systems for controlling aircraft, ships, etc. For example, Patent Document 1 discloses an invention for a communication system that increases the amount of information in a single message between a program in a connected terminal and a control terminal, and displays information on the occurrence of events in each connected terminal and information on the occurrence of errors as messages, etc., thereby enabling each connected terminal to grasp the current status of communication in detail. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-301848 A Summary of the Invention [Problem to be solved by the invention]

[0004] In aircraft radio communication, the other party is usually called by voice. Since the other party of communication is an unspecified number of people, controllers at air traffic control agencies and dispatchers at airlines constantly monitor the communication. On the other hand, on board the aircraft, it is necessary to constantly monitor the communication in order to monitor the calls to the aircraft, but constant monitoring requires continuous tension from the crew, which is a heavy burden. For this reason, in civil aviation, instead of constant manual monitoring, a monitoring function by a mechanical system is adopted to reduce the burden on radio operators and pilots. This selective call system for mechanically waiting for automatic calls is called a self-call system.

[0005] The Selcall system is mainly used for communication on civil aircraft. It is a system used by the member countries, organizations, and aircraft companies of the International Civil Aviation Organization (ICAO). The Selcall system determines whether or not the four tones used for a Selcall (call) out of 16 tones with different frequencies are set for the aircraft, and notifies the crew of the result.

[0006] Fig. 1 shows a schematic configuration example of a processing unit related to self-call detection by a radio in an aircraft. As shown in Fig. 1, the radio has an A / D (Analog-to-Digital) conversion unit 11, an orthogonal demodulation unit 12, an IF (Intermediate Frequency) filter 13, an AGC (Automatic Gain Control) unit 14, an SSB (Single Side Band) demodulation unit 15, an audio processing unit 16, a D / A (Digital-to-Analog) conversion unit 17, an IF filter 18, an AGC unit 19, an AM (Amplitude Modulation) demodulation unit 20, and a self-call detection processing unit 21.

[0007] A signal received by the radio is converted from an analog signal to a digital signal by the A / D conversion unit 11, and then undergoes orthogonal demodulation processing by the orthogonal demodulation unit 12. The signal resulting from the processing by the orthogonal demodulation unit 12 is distributed to the IF filter 13 and the IF filter 18, and is filtered by each of the IF filters. The signal resulting from the processing by the IF filter 13 is subjected to gain control processing by the AGC 14, SSB demodulation processing by the SSB demodulation unit 15, and audio processing by the audio processing unit 16, and then converted from a digital signal to an analog signal by the D / A conversion unit 17 and output as a received demodulated audio. The signal resulting from the processing by the IF filter unit 18 is subjected to gain control processing by the AGC 19, AM demodulation processing by the AM demodulation unit 20, and selcall detection processing by the selcall detection processing unit 21. The selcall detection processing unit 21 outputs a selcall detection signal indicating the result of the selcall detection processing.

[0008] The Selcall detection process in the conventional system will be described with reference to Fig. 2. As shown in Fig. 2, the Selcall detection processing unit 21 in the conventional system has 16 bandpass filters 31, 16 averaging units 32, a threshold comparison unit 33, a 16-bit Selcall detection bit flag processing unit 34, a Selcall detection bit decision block 35, and a sequence block 36. The 16 narrowband bandpass filters 31 have passbands set to respectively correspond to tones of 16 different frequencies.

[0009] The AM demodulated signal obtained by AM demodulating the received signal is distributed to 16 narrow-band bandpass filters 31 and filtered. The results of filtering by each bandpass filter are averaged by 16 averaging units 32 provided for each filter, and output to a threshold comparison unit 33. The threshold comparison unit 33 compares the levels (i.e., tone levels) of the 16 signals input from the 16 averaging units 32 with a threshold for detecting a Selcall, and outputs 16 signals indicating the comparison results. The 16-bit Selcall detection bit flag processing unit 34 generates a 16-bit Selcall detection bit signal that expresses the presence or absence of 16 types of tones in bits based on the 16 signals output from the threshold comparison unit 33. The Selcall detection bit determination block 35 determines whether or not two waves of the four types of tones used for Selcall among the tones of 16 types of frequencies have been detected based on the Selcall detection bit signal, and outputs a two-wave detection signal indicating the result. Based on the SEL-call detection bit signal and the two-wave detection signal, the sequence block 36 determines whether the four types of tones used in the SEL-call are intended for the own aircraft, and outputs a SEL-call detection signal indicating the result.

[0010] As described above, in the conventional Selcall system, in order to determine the presence or absence of the four tones used for Selcall among the 16 tones of different frequencies, it was necessary to use 16 types of bandpass filters 41. However, since a large amount of resources are required to realize the above-mentioned processing using digital signal processing, there was a need to reduce the resources used for cell code detection.

[0011] In addition, the setting operation of the self-call code (a code that identifies a self-call) in the radio installed on conventional domestic aircraft was performed using a separate external device attached to the radio. However, when using a fixed-mounted external device, there is a disadvantage that it takes up space inside the aircraft. Also, a mobile terminal-type external device can be used, but it has the disadvantage that it needs to be brought on board every time the self-call code is set, and the self-call code of the aircraft cannot be re-set (changed) while the radio is in operation.

[0012] The present invention has been made in consideration of the above-mentioned conventional circumstances, and has an object to reduce resources used for digital signal processing for Selcall detection. Another object of the present invention is to enable the Selcall code to be changed even while the radio is in operation, without occupying space inside the aircraft. [Means for solving the problem]

[0013] In order to achieve the above object, a wireless communication system according to one aspect of the present invention is configured as follows: That is, in a wireless communication system including a radio device that executes a Selcall detection process for detecting four tones used for Selcalls among 16 tones with different frequencies, the radio device has four multipliers that multiply a signal demodulated from a received signal by the four tones, respectively, and four integrators that integrate the multiplication results by the four multipliers, respectively, and executes the Selcall detection process using levels of the integration results by the four integrators.

[0014] Here, in the above wireless communication system, the radio device may further have four delay adjustment units for synchronizing a tone signal included in a signal demodulated from the received signal with the four types of tones multiplied by the four multipliers, respectively.

[0015] In addition, the above wireless communication system further includes an individual controller connected to the radio, the individual controller having a first operation unit for switching between enabling and disabling a Selcall function, a second operation unit for switching between enabling and disabling a Selcall setting function, a first display unit for displaying whether the Selcall setting function is enabled or disabled, a third operation unit for an operation for setting a Selcall code when the Selcall setting function is enabled, and a second display unit for displaying the set Selcall code, and the second display unit can display a result of the Selcall detection process by the radio. Effect of the Invention

[0016] According to the present invention, it is possible to reduce resources used for digital signal processing for Selcall detection, and it is also possible to change the Selcall code even while the radio is in operation, without occupying space inside the aircraft. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a diagram illustrating an example of a schematic configuration of a processing unit related to detection of a self-call by a wireless device in an aircraft. [Diagram 2] FIG. 1 is a diagram illustrating a process of detecting Selcall in a conventional system. [Diagram 3] 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment of the present invention. [Figure 4] 4 is a diagram illustrating a self-call detection process in the wireless communication system of FIG. 3. [Diagram 5] 4 is a diagram showing an example of the appearance of an individual controller in the wireless communication system of FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] An embodiment of the present invention will be described with reference to the drawings. Fig. 3 shows an example of the configuration of a wireless communication system according to an embodiment of the present invention. The illustrated system includes a radio 41 mounted on an aircraft, and an individual controller 44 which is an interface provided to a user (a radio operator or a pilot) who uses the radio 41. The radio 41 includes a main control unit 42 which controls the operation of the radio 41, and a self-call detection unit 43 which detects self-calls. The individual controller 44 includes a controller control unit 45 which controls the operation of the individual controller 44, an operation unit 46 which accepts various operations from the user, and a display unit 47 which displays various information for the user.

[0019] The schematic configuration of the selcall detection unit 43 is the same as that described with reference to Fig. 1. That is, a signal received by the radio 41 is converted from an analog signal to a digital signal by the A / D conversion unit 11, and then the signal is subjected to orthogonal demodulation processing by the orthogonal demodulation unit 12. The signal resulting from the processing by the orthogonal demodulation unit 12 is distributed to the IF filter 13 and the IF filter 18, and is filtered by each of the IF filters. The signal resulting from the processing by the IF filter 13 is gain controlled by the AGC 14, SSB demodulation processing is performed by the SSB demodulation unit 15, and audio processing is performed by the audio processing unit 16, and then the signal is converted from a digital signal to an analog signal by the D / A conversion unit 17 and output as a received demodulated audio. The signal resulting from the processing by the IF filter unit 18 is gain controlled by the AGC 19, AM demodulation processing is performed by the AM demodulation unit 20, and selcall detection processing is performed by the selcall detection processing unit 21. The selcall detection processing unit 21 outputs a selcall detection signal indicating the result of the selcall detection processing.

[0020] The Selcall detection process in the wireless communication system of this example will be described with reference to Fig. 4. As shown in Fig. 4, the Selcall detection processing unit 21 in the Selcall detection unit 43 of the wireless device 41 of this example has four tone generators 51-1 to 51-4, four delay adjustment units 52-1 to 52-4, four multipliers 53-1 to 53-4, and four integrators 54-1 to 54-4.

[0021] Each of the tone generators 51-1 to 51-4 is set with one of four frequencies f1, f2, f3, and f4 used for the aircraft's self-call. In this example, the tone generator 51-1 is set to generate a tone with a frequency f1, the tone generator 51-2 is set to generate a tone with a frequency f2, the tone generator 51-3 is set to generate a tone with a frequency f3, and the tone generator 51-4 is set to generate a tone with a frequency f4.

[0022] The tone generator 51-1 generates a tone of frequency f1 according to the above settings. The multiplier 53-1 multiplies the AM demodulated signal demodulated from the received signal by the tone of frequency f1 generated by the tone generator 51-1. The tone of frequency f1 generated by the tone generator 51-1 is delayed and adjusted by the delay adjustment unit 52-1 so as to be synchronized with the tone signal included in the AM demodulated signal. The integrator 54-1 integrates the multiplication result by the multiplier 53-1. Here, the delay adjustment mechanism for synchronizing the tones is one in which the amount of delay is changed at regular time intervals to detect the point where the integral value is maximum, but this is merely one example and other mechanisms may be used.

[0023] Similarly, a tone of frequency f2 generated by tone generator 51-2 is delay-adjusted by delay adjustment unit 52-2, then multiplied by the AM demodulated signal by multiplier 53-2, and the result is integrated by integrator 54-2. A tone of frequency f3 generated by tone generator 51-3 is delay-adjusted by delay adjustment unit 52-3, then multiplied by the AM demodulated signal by multiplier 53-3, and the result is integrated by integrator 54-3. A tone of frequency f4 generated by tone generator 51-4 is delay-adjusted by delay adjustment unit 52-4, then multiplied by the AM demodulated signal by multiplier 53-4, and the result is integrated by integrator 54-4.

[0024] Thereafter, the Selcall detection processing unit 21 performs Selcall detection by determining the presence or absence of each tone of frequencies f1, f2, f3, and f4 using the levels of the integration results output from the integrators 54-1 to 54-4. For example, the levels of the integration results output from the integrators 54-1 to 54-4 are compared with a predetermined threshold, and if all of the levels of the integration results output from the integrators 54-1 to 54-4 are equal to or greater than the threshold, it detects a Selcall for the aircraft. Specifically, it determines whether a Selcall has been detected based on whether the peak value of the integration value exceeds the threshold. That is, after peak holding the integration value, it is compared with a predetermined threshold. As a result of comparing the integration value with the threshold, if the integration value is greater than the threshold, it is determined that a detection has been detected, and the above-mentioned Selcall detection bit signal is output. The processing after the output of the Selcall detection bit signal is the same as the conventional example described with reference to FIG. 2, and therefore a detailed description will be omitted.

[0025] FIG. 5 shows an example of the appearance of the individual controller 44 in the Selcall detection system of this example. As shown in FIG. 5, the individual controller 44 of this example has a first operation unit 61 for switching between enabling and disabling the Selcall function, a second operation unit 62 for switching between enabling and disabling the Selcall setting function, a third operation unit 63 for setting a Selcall code when the Selcall setting function is enabled, a first display unit 64 for displaying whether the Selcall setting function is enabled or disabled, and a second display unit 65 for displaying the set Selcall code. The Selcall code is a code for identifying a Selcall for the aircraft. The second display unit 65 has an alphabet display function and can also display the results of the Selcall detection process. The second display unit 65 is composed of, for example, a 14-segment LED. The first operation unit 61, the second operation unit 62, and the third operation unit 63 are merely examples of the operation unit 46 of FIG. 3, and the operation unit 46 may be realized in other ways. Moreover, the first display unit 64 and the second display unit 65 are merely one example of the display unit 47 in FIG. 3, and the display unit 47 may be realized in other ways.

[0026] The main control unit 42 of the wireless device 41 is equipped with software related to each of the above functions and controls each of the above functions. When the self-call function is enabled, the self-call detection unit 43 executes a self-call detection process based on the demodulation result of the received high-frequency signal under the control of the main control unit 42. As a result, when a self-call that matches the self-call code set for the wireless device is detected, the self-call detection unit 43 transmits a self-call detection signal to the main control unit 42. The main control unit 42 that has received the self-call detection signal transmits the self-call detection signal to the controller control unit 45 of the individual controller 44. The controller control unit 45 that has received the self-call detection signal transmits a display signal based on the self-call detection signal to the display unit 47, thereby causing the display unit 47 to output a display indicating that a self-call that matches the self-call code of the wireless device has been detected. In addition to transmitting the self-call detection signal, the self-call detection unit 43 also outputs a self-call detection sound to the user's headset, speaker, or the like.

[0027] When setting the cell code, the operation unit 46 of the individual controller 44 accepts a user's operation, and a signal to activate the cell code setting function is transmitted to the main controller 42 of the radio 41 via the controller control unit 45. The main controller 42 then causes the display unit 47 of the individual controller 44 to display the self-call code via the controller control unit 45, and the self-call code display is changed in response to the operation of the operation unit 46, thereby changing the self-call code setting of the radio. The set value of the cell call code is stored in the memory (not shown) of the radio 41 via the controller control unit 45 and the main control unit 42, and is used in the subsequent self-call detection process.

[0028] When the Selcall function is enabled and a Selcall that matches the Selcall code of the aircraft is detected, the user will be informed of the call to the aircraft by a display on the display unit 47 of the individual controller 44 or a voice from a headset or speaker, etc. Upon noticing the call, the user disables the Selcall function by operating the operation unit 46 of the individual controller 44 and switches to normal transmission / reception mode, thereby beginning communication with the called aircraft. After the communication ends, the user enables the Selcall function by operating the operation unit 46 of the individual controller 44, and waits for the next call to the aircraft.

[0029] As described above, the radio in the self-call detection system of this example has tone generators 51-1 to 51-4 that generate tones of frequencies f1, f2, f3, and f4 used for self-calls of the own aircraft out of 16 tones of different frequencies, multipliers 53-1 to 53-4 that multiply the AM demodulated signal demodulated from the received signal by the tones of frequencies f1, f2, f3, and f4 generated by the tone generators 51-1 to 51-4, respectively, and integrators 54-1 to 54-4 that integrate the multiplication results by the multipliers 53-1 to 53-4, respectively, and detects a self-call for the own aircraft by determining the presence or absence of tones of frequencies f1, f2, f3, and f4 using the levels of the integration results by the integrators 54-1 to 54-4, respectively.

[0030] This configuration eliminates the need for large amounts of resources such as 16 types of narrow-band bandpass filters, thereby reducing the resources used for digital signal processing for Selcall detection.In addition, by equipping the individual controller 44, which is a component of the radio 41, with a Selcall code setting function and a Selcall detection notification function, it becomes possible to change the Selcall code even during operation without occupying space inside the aircraft.

[0031] Although the embodiments of the present invention have been described above, these embodiments are merely illustrative and do not limit the technical scope of the present invention. The present invention can take various other embodiments, and various modifications such as omissions and substitutions can be made without departing from the gist of the present invention. These embodiments and modifications are included in the scope and gist of the invention described in this specification, etc., and are included in the scope of the invention described in the claims and their equivalents.

[0032] Furthermore, the present invention can be provided not only as devices such as those described above or as a system composed of these devices, but also as methods executed by these devices, programs for causing a processor to realize the functions of these devices, and storage media for storing such programs in a computer-readable format. [Industrial Applicability]

[0033] The present invention can be used in a wireless communication system including a radio set that executes a self-call detection process. [Explanation of symbols]

[0034] 11: A / D conversion unit 11, 12: Quadrature demodulation unit, 13: IF filter, 14: AGC 14, 15: SSB demodulation unit, 16: Audio processing unit, 17: D / A conversion unit, 18: IF filter, 19: AGC unit, 20: AM demodulation unit, 21: Selcall detection processing unit, 31: Bandpass filter, 32: Averaging unit, 33: Threshold comparison unit, 34: 16-bit Selcall detection bit flag processing unit, 35: Selcall detection bit decision block, 36: Sequence block, 41: Radio, 42: Main control unit, 43: Selcall detection unit, 44: Individual controller, 45: Controller control unit, 46: Operation unit, 47: Display unit

Claims

1. A wireless communication system including a radio device that executes a self-call detection process for detecting four tones used for a self-call among 16 tones with different frequencies, The wireless communication system is characterized in that the wireless device has four multipliers that multiply the signal demodulated from the received signal by the four types of tones, and four integrators that integrate the multiplication results by the four multipliers, and performs the Selcall detection process using the levels of the integration results by the four integrators.

2. 2. The wireless communication system according to claim 1, a first delay adjustment unit for adjusting a delay time of a first signal included in a signal demodulated from the received signal and a second delay adjustment unit for adjusting a delay time of a first signal included in the ...

3. 2. The wireless communication system according to claim 1, a separate controller connected to the radio; The individual controller has a first operation unit for switching between enabling and disabling the Selcall function, a second operation unit for switching between enabling and disabling the Selcall setting function, a first display unit for displaying whether the Selcall setting function is enabled or disabled, a third operation unit for an operation for setting a Selcall code when the Selcall setting function is enabled, and a second display unit for displaying the set Selcall code, The wireless communication system, wherein the second display unit is capable of displaying a result of the self-call detection process performed by the wireless device.

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