JP5575616B2 - Wireless device - Google Patents

Description

  The present invention relates to a wireless device for receiving a wireless signal.

  In general homes and the like, crime prevention systems that monitor for abnormalities such as the presence of intruders and fires, and notify the abnormality when an abnormality is detected have become widespread. In particular, in recent years, a wireless crime prevention system that transmits a signal wirelessly from a detection sensor, receives the transmitted signal by a receiving device, and performs abnormality notification or the like has been put into practical use.

  FIG. 11 is an explanatory diagram for explaining a configuration of a conventional wireless crime prevention system. As shown in FIG. 11, a wireless crime prevention system 100 includes a wireless opening / closing sensor 101 that detects the open / closed state of a door or window, a wireless fire sensor 102 that detects a fire, and a wireless security sensor that detects a human body. It is configured to include a human sensor 103, a wireless abnormality alarm lamp 104 for informing the outdoors of an abnormality, a repeater 105 that wirelessly relays signals transmitted from these sensors 101 to 103, and a receiving device 106. Yes. The receiving device 106 receives the signals transmitted from the sensors 101 to 103 via the repeater 105 or directly receives the signals, thereby monitoring the presence / absence of the abnormality and detecting the abnormality when detecting the abnormality. A warning signal is transmitted to the lamp 104 wirelessly to notify the abnormality, and if necessary, the abnormality occurrence is transferred to the security company by wire or wirelessly (for example, Patent Document 1 discloses an abnormality detection means. A security system for houses is disclosed).

  In such a wireless crime prevention system 100, since wireless transmission is performed at a short distance of about several meters to several tens of meters, the frequency band for wireless transmission is a 426 MHz band that is a specific low-power security wireless band. It was used. Here, in ARIB STD-30, which is a standard for this specific low-power security radio, carrier sense is not obliged when using radio waves having a frequency of 426.250 MHz or more and 426.8375 MHz or less. Carrier sense refers to sensing the received signal strength of the received power of another radio wave having the same frequency as the carrier frequency in the wireless transmission when performing wireless transmission, and when the received signal strength is equal to or greater than a predetermined threshold. This means that no wireless transmission is performed. Since it has been specified that such carrier sense is not necessary, in the conventional wireless crime prevention system, each of the sensors 101 to 103 performs wireless transmission without performing carrier sense.

Japanese Patent Laid-Open No. 2003-115085

  However, in the conventional wireless crime prevention system 100, only one frequency band such as the 426 MHz band is used as the frequency band for wireless transmission, so the communication speed is as slow as 1,200 bps, for example. It takes time for the wireless signal transmitted from 103 to reach the receiving apparatus 106, and in particular, it takes time to reach the receiving apparatus 106 via the repeater 105.

  In addition, since each sensor 101 to 103 performs wireless transmission without performing carrier sense, when the number of sensors 101 to 103 is increased, the probability that signals collide due to wireless transmission being performed at the same timing. There is a possibility that a signal having a high radio wave intensity does not reach the repeater 105 or the receiving device 106 due to the increase.

  In order to solve such a problem, 1) a carrier sense function is added to each of the sensors 101 to 103, 2) a wireless transmission frequency band of each sensor has a higher communication speed than the 426 MHz band, and It may be possible to change to a frequency band (for example, 950 MHz band) where carrier sense is obligatory. However, in order to change the functions and frequency bands of the sensors 101 to 103 in this way, the existing sensors 101 to 103 with a large number of installations are replaced, or the new sensors 101 to 103 with many types are designed. It needs to be changed and is not realistic.

  Therefore, the inventor of the present application does not perform carrier sense in the 426 MHz band in the wireless transmission from each of the sensors 101 to 103, and on the other hand, the frequency band of the wireless transmission from the repeater 105 to the receiving device 106 We focused on solving the above problems by setting the 950 MHz band to 950 MHz. That is, when the 950 MHz band is used as described above, the communication speed from the repeater 105 to the receiving apparatus 106 can be improved to, for example, 9,600 bps, and wireless transmission from the repeater 105 or the receiving apparatus 106 is possible. Sometimes, by performing carrier sense, a radio signal can surely reach the receiving apparatus 106, and communication reliability can be improved. In particular, in this case, only the functions of the repeater 105 and the receiving device 106 need to be changed. Since the number and types of the repeater 105 and the receiving device 106 are small compared to the sensors 101 to 103, Easy to apply in reality.

  However, in wireless communication using the 950 MHz band, another problem may occur when performing carrier sense. In other words, in the low-power wireless system of 950 MHz band, the 5 MHz band from 950.8 MHz to 955.8 MHz is divided into 24 channels (unit channels) of 200 kHz width, and the band for up to three unit channels is used simultaneously. Therefore, by measuring the output voltage from the antenna, the received signal strength in each channel is measured, the vacant channel is identified, and the channel actually used is selected. ing. However, conventionally, the measurement circuit for the output voltage from the antenna has a characteristic that the received signal strength is lowered at the median value (center frequency) of the frequency band to be measured as the characteristic of the bandpass filter provided internally for channel selection. Therefore, the true value of the received signal strength in each unit channel cannot be detected accurately, and there is a possibility that an empty unit channel cannot be specified accurately.

  The present invention has been made in view of the above, and even in the case of using a measurement circuit having a characteristic that the received signal strength of the center frequency of the frequency band to be measured decreases, in each unit channel An object of the present invention is to provide a wireless device that can improve the measurement accuracy of received signal strength.

  In order to solve the above-described problems and achieve the object, a wireless device according to claim 1 is a wireless device that receives a signal from a terminal device, and includes a wireless transmission / reception unit including an antenna, and the wireless transmission / reception unit A control unit that performs control based on the content of the signal received at the wireless transceiver unit, and measures the received signal strength of each of a plurality of unit channels of a certain width included in a predetermined band A carrier sense unit that identifies a vacant channel that is an empty unit channel among the plurality of unit channels based on the received signal strength, wherein the carrier sense unit receives a received signal among the plurality of unit channels. Measure the received signal strength of the measurement execution frequency that is different from the measurement target frequency, which is the center frequency of the unit channel whose strength is to be measured, by a predetermined frequency. The received signal strength of the measurement target frequency calculated based on the received signal strength measurements performed frequency was boss, identifies a vacant channel based on the received signal strength the calculation.

  Further, the radio device according to claim 2 is the radio device according to claim 1, wherein the carrier sense unit has a frequency lower than the measurement target frequency by the predetermined frequency as a received signal strength of the measurement execution frequency. The reception signal strength of the first measurement execution frequency on the side and the reception signal strength of the second measurement execution frequency higher by the predetermined frequency than the measurement target frequency are measured, and the measured first measurement execution frequency is received. The received signal strength of the measurement target frequency is calculated based on the signal strength and the received signal strength of the second measurement execution frequency.

  Further, in the wireless device according to claim 3, in the wireless device according to claim 1 or 2, the carrier sense unit measures the received signal strength of the measurement execution frequency a plurality of times, and the measurement is performed a plurality of times. Based on the maximum value of the received signal strength, the received signal strength of the measurement target frequency is calculated.

  According to a fourth aspect of the present invention, in the wireless device according to any one of the first to third aspects, the control unit is housed in a first housing, and the wireless transmission / reception unit is disposed in the first housing. It provided in the 2nd housing | casing comprised so that attachment or detachment with respect to the body was possible.

  Moreover, the radio | wireless apparatus of Claim 5 is a radio | wireless apparatus as described in any one of Claim 1 to 4, The said radio | wireless apparatus transmits the signal from a security sensor directly or the relay for disaster prevention It is a receiver which receives via.

  According to the wireless device of claim 1, the received signal strength of the measurement target frequency is calculated based on the received signal strength of the measurement execution frequency, and the empty channel is specified based on the calculated received signal strength. Even when using a measurement circuit that has the characteristic of reducing the received signal strength at the center frequency of the target frequency band, it is possible to improve the measurement accuracy of the true value of the received signal strength in each unit channel Become.

  In addition, according to the wireless device of the second aspect, the received signal strength of the first measurement execution frequency lower than the measurement target frequency and the reception of the second measurement execution frequency higher than the measurement target frequency. Since the received signal strength of the measurement target frequency is calculated based on the signal strength, for example, an average value of the received signal strength of the first measurement execution frequency and the received signal strength of the second measurement execution frequency is set as the measurement target frequency. Thus, it is possible to calculate the received signal strength of the frequency to be measured relatively easily.

  Further, according to the radio device according to claim 3, since the received signal strength of the measurement target frequency is calculated based on the maximum value of the received signal strength measured a plurality of times, a measurement error is added to the received signal strength of the measurement execution frequency. Even if there is, there is actually a signal with a received signal strength exceeding the predetermined received signal strength, but it is determined that such a signal is not output and the signal is transmitted Can be prevented.

  In addition, according to the wireless device of the fourth aspect, by unitizing the wireless transmission / reception unit, only the wireless transmission / reception unit is provided for the specific low-power security wireless standard necessary for transmitting / receiving a wireless signal of 950 MHz band. What is necessary is just to acquire as a target, and since it becomes unnecessary to acquire a radio | wireless standard in the whole radio | wireless apparatus, it becomes possible to acquire a radio | wireless standard easily. In addition, the wireless transmission / reception unit can be unitized to provide versatility, and the wireless transmission / reception unit can be easily attached to a wireless device or repeater having a configuration different from that of the wireless device. Become. Further, each part of the wireless device excluding the wireless transmission / reception unit may be configured to handle only the control of the signal of the 426 MHz band as in the conventional case, so that the improvement associated with the handling of the signal of the 950 MHz band is unnecessary. Become.

  Further, according to the wireless device of the fifth aspect, since it is not necessary to provide a control unit for each frequency band in the receiving device that receives a signal from the security sensor, the receiving device is configured simply and inexpensively. Can do.

It is explanatory drawing for demonstrating the structure of the wireless crime prevention system which concerns on embodiment of this invention. It is a block diagram which shows the electric constitution of a portable setting apparatus. It is a block diagram which shows the electric constitution of a repeater. It is a graph which shows the detection characteristic by a 2nd signal processing part. Is a diagram showing the measurement state of the second signal processing unit is a diagram showing the measurement conditions first received signal strength Ls ₁ of the first measurement executing frequency fs _1. Is a diagram showing the measurement state of the second signal processing section, a diagram illustrating a second measurement conditions of the measurement performed a second received signal strength of a frequency fs ₂ Ls _2. It is a figure which shows the measurement condition of a 2nd signal processing part, and is a figure which shows a received signal strength peak superposition | polymerization point. It is a block diagram which shows the electric constitution of a receiver. It is a disassembled perspective view for demonstrating the attachment / detachment structure of the radio | wireless transmission / reception part with respect to a receiver. It is explanatory drawing for demonstrating transmission / reception of the signal in a crime prevention system. It is explanatory drawing for demonstrating the structure of the conventional radio | wireless crime prevention system.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. However, the present invention is not limited by this embodiment.

(Overview)
First, the outline of the wireless crime prevention system will be described. FIG. 1 is an explanatory diagram for explaining a configuration of a wireless crime prevention system according to the present embodiment. As shown in FIG. 1, a wireless crime prevention system 1 includes an open / close sensor 10, a fire sensor 11, a human sensor 12, an abnormality notification lamp (outdoor indicator lamp) 13, a repeater 30, and a receiver (a crime prevention receiver). , Center device) 40. Among these, each apparatus except the abnormality notification lamp 13 is disposed indoors in the house, and the abnormality notification lamp 13 is installed outside the house (for example, near the entrance). In the following description, the opening / closing sensor 10, the fire sensor 11, and the human sensor 12 are collectively referred to as “security sensor 2” as necessary, and the security sensor 2 and the abnormality notification lamp 13 are referred to as “ Collectively referred to as “security terminal 3”. Here, one each of the open / close sensor 10, the fire sensor 11, the human sensor 12, the abnormality notification lamp 13, and the repeater 30 are provided, but any plurality may be provided.

  Further, the security system 1 of the present embodiment is configured to include a portable setting device 20 unlike the conventional security system shown in FIG. The portable setting device 20 is setting means for remotely setting the security alert state of the receiving device 40 wirelessly. For example, the portable setting device 20 is carried by a user or used in an arbitrary place within a range where radio waves reach the indoor repeater 30 or receiving device 40. In particular, when the receiving device 40 is installed in the living room and the living room is away from the entrance, it takes time until the user releases the security mode in the living receiving device 40 after the user returns home. Since there is a possibility that the crime prevention mode cannot be canceled in time, the convenience of the user can be improved by arranging the portable setting device 20 in the vicinity of the entrance.

  In this security system 1, two frequency bands are used in combination as frequency bands for transmitting and receiving signals. Specifically, the 426 MHz band is used between the security terminal 3 and the repeater 30 or the receiving device 40. Further, the 950 MHz band is used among the portable setting device 20, the repeater 30, and the receiving device 40. That is, the repeater 30 and the receiving device 40 transmit and receive signals in two frequency bands, a 426 MHz band (first frequency band) and a 950 MHz band (second frequency band). In this way, by using the 950 MHz band in addition to the conventional 426 MHz band, high-speed processing of setting information and the like is achieved by improving the communication speed, and communication reliability is improved. In particular, the security terminal 3 communicates only in the conventional 426 MHz band, so there is no need to replace existing ones or change the design. On the other hand, the repeater 30 and the receiving device 40 need to transmit and receive signals in two frequency bands, but by providing only one control unit 44 to be described later for signal processing, it is simple and inexpensive. The structure allows two frequency bands to be used together. A specific structure for this will be described later.

(Configuration-security terminal)
Next, the configuration of the wireless crime prevention system 1 will be described. First, the configuration of the security terminal 3 will be described. However, since the open / close sensor 10, the fire sensor 11, the human sensor 12, and the abnormality notification lamp 13 can be configured in the same manner as in the past, only the outline thereof will be described here. The open / close sensor 10 is a wireless open / close detection means for detecting the open / closed state of the door or window by magnetism or the like. When the open / close sensor 10 detects that the door or window is open, a signal to that effect is wirelessly transmitted. Send in. The fire sensor 11 is a fire detection means for detecting the occurrence of a fire by detecting smoke or heat. When a fire occurrence is detected, a signal to that effect is transmitted wirelessly. The human sensor 12 is a human body detection unit that detects a human body by detecting infrared rays. When a human body is detected, the human sensor 12 wirelessly transmits a signal to that effect. The abnormality notification lamp 13 is an abnormality occurrence notifying means for notifying the occurrence of an abnormality such as a fire outdoors by turning on or blinking when a transfer signal is received from the receiving device 40. However, the detection principle in these security terminals 3 is arbitrary, and other known principles can be used.

(Configuration-portable setting device)
The portable setting device 20 is a wireless device for setting a security alert state in the receiving device 40 by transmitting a wireless signal to the receiving device 40. FIG. 2 is a block diagram showing an electrical configuration of the portable setting device 20. As shown in FIG. 2, the portable setting device 20 includes various button groups 22 and an indicator lamp group 23 on the front surface of the housing, and a wireless transmission / reception unit 24, a speaker 25, and a storage unit inside the housing. 26, a power supply unit 27, and a control unit 28 are accommodated.

  The button group 22 includes an emergency button 22a, a start button 22b, a security button 22c, and a release button 22d. The indicator lamp group 23 includes an emergency lamp 23a, an alarm lamp 23b, an OK lamp 23c, an NG lamp 23d, a guard lamp 23e, and a release lamp 23f.

  The wireless transmission / reception unit 24 transmits and receives wireless signals in the 950 MHz band, and includes a dedicated antenna 24a in the 950 MHz band. The speaker 25 outputs an alarm sound. The storage unit 26 is configured by, for example, a flash memory (the same applies to storage units 32 and 42 described later), and stores programs and parameters necessary for control of the portable setting device 20. The power supply unit 27 includes a battery (not shown), and supplies power supplied from the battery to each unit of the portable setting device 20. The control unit 28 includes, for example, a CPU (Central Processing Unit) (not shown) and a program executed on the CPU. In particular, the control unit 28 includes a signal processing unit 28a. When transmitting a radio signal, the signal processing unit 28a performs carrier sense by a known method, and transmits the radio signal only when radio in the same frequency band is not detected.

  In the portable setting device 20 configured as described above, when the emergency button 22a is pressed, an emergency signal is transmitted to the receiving device 40 via the wireless transmission / reception unit 24, and the emergency light 23a is turned on or blinking (hereinafter referred to as “emergency light”). The lighting or flashing is simply described as lighting). When the emergency signal is received by the receiving device 40, the emergency signal is transferred from the receiving device 40 to the security company, and the security guard rushes to the house.

  When the security button 22c is pressed, the security lamp 23e is turned on. When the start button 22b is pressed in this state, a security request signal is transmitted via the wireless transmission / reception unit 24. When the guard request signal is received by the receiving device 40, the crime prevention mode of the receiving device 40 is set to the outing guard mode. Here, the outing security mode is a mode in which the security company performs monitoring when the user goes out. When an abnormality occurs, an abnormal signal is transferred from the receiving device 40 to the security company, and the security guard rushes to the house. . When the crime prevention mode of the receiving device 40 is set to the outing security mode in this way, a security confirmation signal is transmitted from the receiving device 40, and this security confirmation signal is transmitted via the wireless transmission / reception unit 24 of the portable setting device 20. If received, the OK lamp 23c is turned on. On the other hand, when the security confirmation signal is not received by the portable setting device 20 within a predetermined time after the start button 22b is pressed, the NG lamp 23d is turned on.

  When the release button 22d is pressed, the release lamp 23f is turned on. When the start button 22b is pressed in this state, a release request signal is transmitted via the wireless transmission / reception unit 24. When the release request signal is received by the receiving device 40, the crime prevention mode of the receiving device 40 is released. When the crime prevention mode is released in this way, a release confirmation signal is transmitted from the receiving device 40, and when this release confirmation signal is received via the wireless transmission / reception unit 24 of the portable setting device 20, the OK light 23c. Lights up. On the other hand, when the release confirmation signal is not received by the portable setting device 20 within a predetermined time after the start button 22b is pressed, the NG lamp 23d is turned on.

(Configuration-repeater)
1 is a relay means for receiving a signal wirelessly transmitted from the security sensor 2 and transmitting the received signal to the portable setting device 20 or the receiving device 40. It is a radio device for a security system to receive. The repeater 30 is also a relay unit that receives a signal wirelessly transmitted from the receiving device 40 and transmits the signal to the portable setting device 20 or the abnormality notification lamp 13. The repeater 30 is disposed between the security sensor 2 and the receiving device 40, or is disposed between the receiving device 40 and the abnormality notification lamp 13.

  FIG. 3 is a block diagram showing an electrical configuration of the repeater 30. As shown in FIG. 3, the repeater 30 includes a wireless transmission / reception unit 31, a storage unit 32, a power supply unit 33, and a control unit 34. The wireless transmission / reception unit 31 transmits / receives signals in the 426 MHz band and the 950 MHz band. Details of the wireless transmission / reception unit 31 will be described later. The storage unit 32 stores programs and parameters necessary for controlling the repeater 30. The power supply unit 33 includes a battery (not shown), and supplies power supplied from the battery to each unit of the repeater 30. The control unit 34 is a control unit that controls each unit of the repeater 30.

  Here, details of the wireless transmission / reception unit 31 will be described. The wireless transmission / reception unit 31 includes an antenna 35, an antenna side connection unit 36, a first signal processing unit 37, a second signal processing unit 38, and a control unit side connection unit 39. Only one antenna 35 is provided, and this antenna 35 is used in combination for transmission and reception of signals in two frequency bands of the 426 MHz band and the 950 MHz band. For example, the total length L of the antenna 35 is determined to be a quarter wavelength of 426 MHz and a fifth wavelength of 950 MHz so that the 426 MHz band and the 950 MHz band can be used together. The antenna side connection part 36 is a connection terminal connected to the antenna 35.

  The first signal processing unit 37 processes a 426 MHz band signal, and includes an LPF (low-pass filter) 37a and a first basic processing unit 37b. The LPF 37a is a first frequency band passing means that allows only signals below the vicinity of the 426 MHz band to pass. The LPF 37a may be a BPF (band pass filter) that allows only the vicinity of the 426 MHz band to pass. The first basic processing unit 37b converts the signal in the first frequency band received by the antenna 35 and input through the antenna side connection unit 36 into a signal of a predetermined first method, and controls the control unit side connection unit 39. The first system signal input from the control unit 34 via the control unit side connection unit 39 is output to the antenna 35 via the antenna side connection unit 36 in the first frequency band. .

  The second signal processing unit 38 processes a 950 MHz band signal, and includes an HPF (High Pass Filter) 38a, a second basic processing unit 38b, and a compatible processing unit 38c. The HPF 38a is a first frequency band passing means that allows only signals in the vicinity of the 950 MHz band or higher to pass. The HPF 38a may be a BPF (band pass filter) that passes only the vicinity of the 950 MHz band. The second basic processing unit 38b converts the second frequency band signal received by the antenna 35 and input via the antenna side connection unit 36 into a predetermined second system signal and outputs the second system signal. Is output to the antenna 35 via the antenna side connection section 36 in the second frequency band. The compatible processing unit 38c converts the signal output from the second basic processing unit 38b into the second system signal and converts the signal into the first system signal, and sends it to the control unit 34 via the control unit side connection unit 39. In addition to outputting, the first system signal input from the control unit 34 via the control unit side connection unit 39 is converted into a second system signal and output to the second basic processing unit 38b.

  In particular, the first signal processing unit 37 transmits a radio signal in the 426 MHz band without performing carrier sense, and the second signal processing unit 38 performs a carrier sense in a known method when transmitting a radio signal in the 950 MHz band. The radio signal is transmitted only when radio in the same frequency band is not detected.

  Of the components of the wireless transmission / reception unit 31 configured as described above, the components other than the antenna 35 are mounted on both surfaces of the same base and modularized. More specifically, for example, the first basic processing unit 37b and the second basic processing unit 38b are each configured by a wireless IC, and the compatible processing unit 38c is configured by a microcomputer, and the wireless IC and the microcomputer are the same. It is mounted on both sides of the board. In designing this mounting layout, a configuration for preventing mutual interference between a signal of 426 MHz band and a signal of 950 MHz band (for example, installation of an impedance for reducing power supply noise, disposition of 426 MHz system and 950 MHz system, noise It is preferable to employ a shield installation or the like.

  Here, the carrier sense at the time of 950 MHz band transmission by the second signal processing unit 38 will be described. As described above, in the low power wireless system of 950 MHz band, the 5 MHz band from 950.8 MHz to 955.8 MHz is divided into 24 channels (unit channels) with a width of 200 kHz, and a band corresponding to a maximum of three unit channels. Can be transmitted simultaneously. For this reason, the second signal processing unit 38 measures the received signal strength in each unit channel by measuring the output voltage from the antenna 35, and vacant unit channels (the received signal strength does not exceed -75 dB). A channel (hereinafter referred to as an empty channel) is specified and a unit channel to be actually used is selected (that is, the second signal processing unit 38 corresponds to the carrier sense unit in the claims).

  FIG. 4 is a graph showing the detection characteristics of the second signal processing unit 38. In FIG. 4, the horizontal axis is a frequency shift (measurement frequency shift with respect to the center frequency fc of the frequency band. Unit = kHz), and the vertical axis is the received signal strength (RSSI value. Here, the RSSI of a signal of −75 dBm input) (Shown as a range from a maximum value of 100 to a minimum value of 0) (same in FIGS. 5 and 6 to be described later). As shown in FIG. 4, the detection characteristic of the second signal processing unit 38 is the reception at the center frequency (hereinafter, measurement target frequency) fc of the frequency band of the channel to be measured (here, the unit channel of 200 KHz width). Although the signal strength is actually at a peak level comparable to the received signal strength of the frequencies before and after that, the detected received signal strength is the received signal strength shown in FIG. 4 and at the center frequency fc. Since the received signal strength is reduced (valley = dip can be made), it is difficult to accurately detect the true value of the received signal strength in the unit channel. In particular, when the frequency band (band) of the unit channel to be detected is wide, the entire band cannot be covered with a single bandpass filter. Therefore, in order to improve detection accuracy, the frequency is divided (divided into multiple bands). And see) As described above, the received signal strength of the center frequency fc is reduced because the FSK signal that is the measurement target of the received signal strength in the second signal processing unit 38 is high / low of the digital binary value after A / D conversion. This is because the frequency between the frequency assigned to High and the frequency assigned to Low is between, and the energy is lowered.

  Therefore, the second signal processing unit 38 has a predetermined frequency (hereinafter referred to as an adjustment frequency) fd with respect to the measurement target frequency fc that is the center frequency of the unit channel that is the measurement target of the received signal strength among the plurality of unit channels. The received signal strength Ls of the frequency fs that is different from each other (hereinafter referred to as measurement execution frequency) fs is measured, and the received signal strength Lc of the measurement target frequency fc is calculated based on the measured received signal strength Ls of the measurement execution frequency fs. An empty channel is specified based on the received signal strength Lc.

5 and 6 are diagrams illustrating measurement states of the second signal processing unit 38. FIG. First, as shown in FIG. 5, the second signal processing unit 38 receives the received signal intensity of the measurement execution frequency fs (hereinafter, the first measurement execution frequency fs ₁ ) lower than the measurement target frequency fc by the adjustment frequency fd. Ls (hereinafter referred to as first received signal strength Ls ₁ ) is measured by a known method. Next, as shown in FIG. 6, the second signal processing unit 38 receives the received signal intensity of the measurement execution frequency fs (hereinafter, the second measurement execution frequency fs ₂ ) higher than the measurement target frequency fc by the adjustment frequency fd. Ls (hereinafter, second received signal strength Ls ₂ ) is measured by a known method.

Here, the adjustment frequency fd is determined by at least 1) the first measurement execution frequency fs ₁ and the second measurement execution frequency fs ₂ being within the range of the frequency band (200 kHz in this case) of the unit channel to be measured. And 2) the first measurement execution frequency fs ₁ and the second measurement execution frequency fs ₂ are detected by the second signal processing unit 38 so that they are within the measurable range of the second signal processing unit 38. From this point of view, it is determined to be a frequency at which a true value or a value very close to the true value can be obtained. Here, in the detection characteristics by the second signal processing unit 38 shown in FIG. 4, the measurement target frequency fc is on the low-frequency side and the high-frequency side with respect to the portion where the received signal strength decreases at the measurement target frequency fc. The frequency between the two vertices is set to the adjustment frequency fd (for example, 25 kHz). That is, as shown as “received signal intensity peak overlap point” in FIG. 7, the received signal intensity of the first measurement execution frequency fs ₁ (frequency deviation = −25 kHz) in the measurement target frequency fc (frequency deviation = 0 kHz). The adjustment frequency fd is set so that the peak of the waveform and the peak of the waveform of the received signal intensity at the first measurement execution frequency fs ₂ (frequency deviation = 25 kHz) overlap each other. In particular, as shown in FIGS. 5 and 6, the distribution characteristic of the received signal intensity has a broad peak around the measurement target frequency fc, and the peak value is within a range shifted by the adjustment frequency fd before and after. Since the frequency is almost constant, an accurate peak can be obtained even when a peak having a frequency shifted from the measurement target frequency fc by the adjustment frequency fd is used.

The second signal processing unit 38, based on the measured first received signal strength Ls ₁ and the second received signal strength Ls ₂ of the second measurement execution frequency fs _2, the received signal strength Lc of measured frequency fc Calculate. For example, the maximum value of the first received signal strength Ls _{1 and} the maximum value of the second received signal strength Ls ₂ are respectively calculated, and the larger one of the calculated maximum values is determined as the received signal of the measurement target frequency fc. The strength is Lc. By performing such measurement, it is possible to improve the measurement accuracy of the true value of the received signal strength Lc of the measurement target frequency fc. However, as a specific method for calculating the received signal strength Lc based on the first received signal strength Ls ₁ and the second received signal strength Ls ₂ , another method may be adopted, for example, the first received signal strength Ls _2. An average value of the signal strength Ls ₁ and the second received signal strength Ls ₂ may be calculated, and the calculated average value may be used as the received signal strength Lc.

In addition, the second signal processing unit 38 measures the first received signal strength Ls ₁ and the second received signal strength Ls _{2 a} predetermined plurality of times (for example, several tens of times) at the time of this measurement. From the measured first received signal strength Ls ₁ and second received signal strength Ls ₂ , the maximum value of the first received signal strength Ls _{1 and} the maximum value of the second received signal strength Ls ₂ are respectively selected and selected. Based on the maximum value of the first received signal strength Ls _{1 and} the maximum value of the second received signal strength Ls ₂ , the received signal strength Lc is calculated by the above method. By performing such a measurement, even if there is a measurement error in the first received signal strength Ls ₁ and the second received signal strength Ls ₂ , a signal with a received signal strength exceeding −75 dB is actually output. Nevertheless, it is possible to prevent a situation in which it is determined that such a signal is not output and a signal is transmitted.

  The second signal processing unit 38 sequentially performs such a measurement while shifting the measurement target frequency fc for each of the 24 unit channels, and whether the received signal strength Lc calculated by the above method exceeds −75 dB. If it does not exceed -75 dB, the unit channel is specified as an empty channel. Then, a maximum of three empty channels are selected from the specified empty channels by a predetermined method, and transmission is performed using the bandwidths of the selected empty channels at the same time.

(Configuration-Receiver)
Next, the receiving device 40 in FIG. 1 will be described. The receiving device 40 is a control device that monitors the presence or absence of an abnormality by receiving a signal transmitted from the security sensor 2 via the repeater 30 or by directly receiving the signal. The signal from the security sensor 2 It is a wireless receiver for a crime prevention system that receives When the receiving device 40 detects an abnormality, the abnormality notification lamp 13 is wirelessly transmitted to the abnormality notification lamp 13 to notify the abnormality, and if necessary, an abnormality occurrence is wired or wirelessly to the security company. It is also a wireless repeater for transferring information. The receiving device 40 is installed, for example, in a place (typically, an entrance or a living room) that is easy for a user to visually recognize indoors.

  FIG. 8 is a block diagram showing an electrical configuration of the receiving device 40. As shown in FIG. 8, the reception device 40 is configured to accommodate a wireless transmission / reception unit 41, a storage unit 42, a power supply unit 43, and a control unit 44. The storage unit 42 stores programs and parameters necessary for controlling the receiving device 40. The power supply unit 43 supplies power supplied from a commercial power supply to each unit of the receiving device 40. The control unit 44 controls each unit of the receiving device 40.

  The wireless transmission / reception unit 41 is a wireless transmission / reception unit that transmits and receives signals in the 426 MHz band and the 950 MHz band. The antenna 45, the antenna side connection unit 46, the first signal processing unit 47, the second signal processing unit 48, and the control unit side A connection unit 49 is provided. The first signal processing unit 47 includes an LPF 47a and a first basic processing unit 47b, and the second signal processing unit 48 includes an HPF 48a, a second basic processing unit 48b, and a compatibility processing unit 48c. Since each part of these radio | wireless transmission / reception parts 41 can be comprised similarly to each part of the same name in the radio | wireless transmission / reception part 31 of the repeater 30, except the structure to mention specially, the detailed description is abbreviate | omitted.

  Particularly, when the second signal processing unit 48 performs carrier sense to transmit a signal of 950 MHz band, the second signal processing unit 48, in the same way as the second signal processing unit 38, receives the measurement target of the received signal strength in a plurality of unit channels. The received signal strength Ls of the measurement execution frequency fs that is different from the measurement target frequency fc of the unit channel by the adjustment frequency fd is measured, and the measurement target frequency fc is measured based on the received signal strength Ls of the measured measurement execution frequency fs. The received signal strength Lc is calculated, and an empty channel is specified based on the calculated received signal strength Lc.

  Here, the attachment / detachment structure of the wireless transmission / reception part 41 with respect to the receiver 40 is demonstrated. FIG. 9 is an exploded perspective view for explaining the attachment / detachment structure of the wireless transmission / reception unit 41 with respect to the reception device 40. As shown in FIG. 9, the housing (first housing) 40a of the receiving device 40 is formed with a housing portion 40b which is a recess for detachably housing the wireless transmission / reception unit 41. The unit 40b is provided with a connection terminal 40c (not shown in FIG. 8) for connecting to the control unit side connection unit 49 of the wireless transmission / reception unit 41. On the other hand, the wireless transmission / reception unit 41 is a housing different from the housing 41a of the reception device 40, and is provided in a housing (second housing) 41a having an outer shape corresponding to the housing unit 40b. Specifically, the antenna side connection unit 46, the first signal processing unit 47, and the second signal processing unit 48 of the wireless transmission / reception unit 41 are accommodated inside the housing 41a, and an antenna is provided outside the housing 41a. 45 and the control part side connection part 49 are arrange | positioned. And in the state which accommodated the radio | wireless transmission / reception part 41 in the accommodating part 40b, the radio | wireless transmission / reception part 41 is connected to the control part 44 by connecting the control part side connection part 49 to the connection terminal 40c.

  Thus, the effect of unitizing the wireless transmission / reception unit 41 is as follows. That is, as described above, the control unit 44 of the receiving device 40 only needs to control the 426 MHz band signal as in the conventional case, and does not need to control the 950 MHz band signal. The signal may be processed and controlled only by the wireless transmission / reception unit 41. Therefore, by unitizing the wireless transmission / reception unit 41, the specific low-power security wireless standard necessary for transmitting / receiving a wireless signal in the 950 MHz band may be acquired only for the wireless transmission / reception unit 41. Since it is not necessary to acquire the wireless standard as a whole, it is possible to easily acquire the wireless standard. In addition, the wireless transmission / reception unit 41 can be unitized so as to have versatility, and the wireless transmission / reception unit 41 can be easily attached to a reception device or a repeater having a configuration different from that of the reception device 40. Is possible. In addition, by adopting the same shape as the unit of the wireless transmission / reception unit of the conventional receiving device 106 only for the 426 MHz band, even when the 950 MHz band is added as the frequency band of the signal to be used, the transmission / reception unit becomes the unit compatible with the 950 MHz band of the present application. By replacing, it is possible to construct a crime prevention system that can easily transmit and receive in a plurality of bands. Furthermore, each part of the receiving device 40 except the wireless transmission / reception unit 41 may be configured to handle only the control of the 426 MHz band signal, etc., as in the prior art, so there is an improvement associated with handling the 950 MHz band signal. It becomes unnecessary.

(processing)
Next, the process which the crime prevention system 1 comprised as mentioned above performs is demonstrated. FIG. 10 is an explanatory diagram for explaining transmission / reception of signals in the security system 1. In the following, “step” is abbreviated as “S”.

  As shown in FIG. 10, the security sensor 2 transmits an abnormality detection signal without performing carrier sense in the 426 MHz band (SA1). When the abnormality detection signal is received by the repeater 30, the first basic processing unit 37b of the first signal processing unit 37 of the repeater 30 converts the abnormality detection signal into a command of the first command system and converts it into a control unit. 34, the control unit 34 determines whether or not the abnormality detection signal is relayed based on this command. When relaying, the control unit 34 transmits a relay instruction based on a command of the first command system to the first basic processing unit 37b, and the first basic processing unit 37b receiving the relay instruction transmits the abnormality detection signal to the carrier sense. Without being transmitted to the receiver 40 in the 426 MHz band which is the same frequency band as the signal received via the antenna 35 (SA2).

  When the abnormality detection signal from the security sensor 2 is directly received by the reception device 40 or when it is received via the repeater 30, the first signal processing unit is used in the wireless transmission / reception unit 41 of the reception device 40. 47, the first basic processing unit 47b converts the abnormality detection signal into a command of the first command system and transmits it to the control unit 44. The control unit 44 performs a predetermined response according to the content of the abnormality detection signal based on the command. Process. Further, when an abnormality detection signal from the security sensor 2 is received via the repeater 30, in the wireless transmission / reception unit 41 of the receiving device 40, the first basic processing unit 48b of the second signal processing unit 48 detects the abnormality. The signal is converted from the second command system to a command of the first command system and transmitted to the control unit 44, and the control unit 44 performs a predetermined process according to the content of the abnormality detection signal based on the command. As part of such processing, the control unit 44 of the receiving device 40 transmits an instruction to turn on the abnormality notification lamp 13 to the first basic processing unit 47b as a command of the first command system as necessary, and this relay Upon receiving the instruction, the first basic processing unit 47b transmits a transfer signal in the 426 MHz band via the antenna 45 without performing carrier sense, and the abnormality notification lamp 13 that has received the transmission signal displays an abnormality notification. (SA3).

  In addition, the portable setting device 20 transmits a request signal after performing carrier sense in the 950 MHz band in which the transmission speed is set faster than the 426 MHz band (SA4). When this request signal is received by the repeater 30, the second basic processing unit 38b of the second signal processing unit 38 of the repeater 30 converts the request signal into a command of the second command system, and the compatible processing unit 38c. The compatibility processing unit 38c converts the command of the second command system into a command of the first command system and transmits it to the control unit 34. The control unit 34 determines whether the request signal needs to be relayed based on the command. Make a decision. When relaying, the control unit 34 transmits a relay instruction by a command of the first command system to the compatible processing unit 38c, and the compatibility processing unit 38c converts the command of the first command system into a command of the second command system. Is output to the second basic processing unit 38b, and the second basic processing unit 38b performs carrier sensing on the request signal and then transmits it to the receiving device 40 in the 950 MHz band, which is the same frequency band as the signal received via the antenna 35. To send (SA5).

  When the request signal from the portable setting device 20 is directly received by the receiving device 40 or when the request signal is received via the repeater 30, the wireless transmission / reception unit 41 of the receiving device 40 performs the second signal processing. The second basic processing unit 48b of the unit 48 converts the request signal into a command of the second command system and outputs it to the compatibility processing unit 48c. The compatibility processing unit 48c converts the command of the second command system of the first command system. It converts into a command and transmits to the control part 44, and the control part 44 performs the predetermined process according to the content of the request signal based on this command. As a part of such processing, the control unit 44 of the receiving device 40 transmits a confirmation signal transmission instruction by a command of the first command system to the compatible processing unit 48c as necessary, and the compatible processing unit 48c The command of the first command system is converted into the command of the second command system and output to the second basic processing unit 48b, and the second basic processing unit 48b receives the confirmation signal via the antenna 45 after performing carrier sense. Is transmitted in the 950 MHz band, which is the same frequency band as the received signal (SA6).

  When this confirmation signal is received by the repeater 30, the second basic processing unit 38b of the second signal processing unit 38 of the repeater 30 converts this confirmation signal into a command of the second command system, and the compatible processing unit 38c. The compatibility processing unit 38c converts the command of the second command system into a command of the first command system and transmits the command to the control unit 34. The control unit 34 determines whether the confirmation signal needs to be relayed based on the command. Make a decision. When relaying, the control unit 34 transmits a relay instruction by a command of the first command system to the compatible processing unit 38c, and the compatibility processing unit 38c converts the command of the first command system into a command of the second command system. Is output to the second basic processing unit 38b, and the second basic processing unit 38b performs carrier sensing and transmits the confirmation signal in the 950 MHz band via the antenna 35 (SA7).

  When the confirmation signal from the receiving device 40 is directly received by the portable setting device 20 or when it is received by the portable setting device 20 via the repeater 30, the portable setting device 20 receives the confirmation signal. Is processed by the control unit 28, and predetermined processing corresponding to the content of the confirmation signal is performed.

(effect)
As described above, according to the present embodiment, the received signal strength Lc of the measurement target frequency fc is calculated based on the received signal strength Ls of the measurement execution frequency fs, and the empty channel is specified based on the calculated received signal strength Lc. Therefore, even when a measurement circuit having a characteristic that the received signal strength at the center frequency of the frequency band to be measured is reduced is used, the measurement accuracy of the true value of the received signal strength in each unit channel is improved. It becomes possible.

The measurement target frequency and the received signal strength Ls ₁ of the first measurement executing frequency fs ₁ lower frequency than fc, measured received signal strength Ls ₂ frequency second measurement execution frequency of the high frequency side than fc fs ₂ based on the bets, measured since the calculated received signal strength Lc of the target frequency fc, for example, first and received signal strength Ls ₁ of the measurement execution frequency fs ₁ between the received signal strength Ls ₂ of the second measurement execution frequency fs ₂ The reception signal strength Lc of the measurement target frequency fc can be calculated relatively easily, for example, by setting the average value to the measurement target frequency fc.

  Further, since the received signal strength Lc of the measurement target frequency fc is calculated based on the maximum value of the received signal strength measured a plurality of times, even if there is a measurement error in the received signal strength Ls of the measurement execution frequency fs, It is possible to prevent a situation in which a signal is transmitted when it is determined that such a signal is not output even though a signal having a received signal strength exceeding the predetermined received signal strength is actually output. .

  Further, by unitizing the wireless transmission / reception unit 41, a specific low-power security wireless standard necessary for transmitting / receiving a wireless signal in the 950 MHz band may be acquired only for the wireless transmission / reception unit 41, and the receiving device Since it is not necessary to acquire the wireless standard for 40 as a whole, it is possible to easily acquire the wireless standard. In addition, the wireless transmission / reception unit 41 can be unitized so as to have versatility, and the wireless transmission / reception unit 41 can be easily attached to a wireless device or a repeater having a configuration different from that of the reception device 40. Is possible. Furthermore, each part of the receiving device 40 except the wireless transmission / reception unit 41 may be configured to handle only the control of the 426 MHz band signal, etc., as in the prior art, so there is an improvement associated with handling the 950 MHz band signal. It becomes unnecessary.

  In addition, since it is not necessary to provide a control unit for each frequency band in the receiving device 40 that receives a signal from the security sensor, the receiving device 40 can be configured simply and inexpensively.

[Modifications to Embodiment]
Although the embodiments of the present invention have been described above, the specific configuration and means of the present invention can be arbitrarily modified and improved within the scope of the technical idea of each invention described in the claims. it can. Hereinafter, such a modification will be described.

(About problems to be solved and effects of the invention)
First, the problems to be solved by the invention and the effects of the invention are not limited to the above-described contents, and the present invention solves the problems not described above or has the effects not described above. There are also cases where only some of the described problems are solved or only some of the described effects are achieved.

(About the purpose and type of communication system)
In the above embodiment, the crime prevention system has been described. However, the present invention can be applied to a communication system of any purpose and type other than this, for example, a wireless residential fire as a terminal device in a disaster prevention system. Communication from a warning device or other battery-powered small wireless device to a receiver as a receiving device, or communication from a portable setting device as a terminal device to an engine starter as a receiving device in an automobile control system Even in this case, the present invention can be applied. Alternatively, the function of the repeater 30 may be built in the portable setting device 20.

(About signal transmission and reception)
In the above embodiment, each of the repeater 30 and the receiving device 40 performs both reception and transmission of signals in two frequency bands, but it is sufficient that only reception of signals in at least two frequency bands can be performed. For example, the repeater 30 receives a signal transmitted from the security sensor 2 in the 426 MHz band and receives a signal transmitted from the receiving device 40 or the portable setting device 20 in the 950 MHz band. You may make it perform with only the 950 MHz band with respect to the apparatus 40 or the portable setting apparatus 20. FIG. The receiving device 40 receives a signal transmitted from the security sensor 2 in the 426 MHz band and receives a signal transmitted from the repeater 30 or the portable setting device 20 in the 950 MHz band. You may make it perform signal transmission to a security company etc. with a wire communication if necessary.

(Signal frequency band)
In the above embodiment, the 426 MHz band and the 950 MHz band are used together, but the other two frequency bands may be used together. Further, the transmission frequency band to be subjected to carrier sense can also be changed according to the combined frequency. In the above embodiment, the second frequency band uses a higher frequency band than the first frequency band, but may be a band having a higher communication speed than the first frequency band. Not exclusively. Or you may make it set the frequency band which performs carrier sense more reliable than signal transmission / reception of a 1st frequency band as a 2nd frequency band.

(About measurement execution frequency)
In the above-described embodiment, the measurement execution frequency fs is the first measurement execution frequency fs _{1 that} is lower than the measurement target frequency fc by the adjustment frequency fd and the first measurement execution frequency fd that is higher than the measurement target frequency fc by the adjustment frequency fd. Although the case where the two measurement execution frequencies fs ₂ are used has been described, the relationship of the measurement execution frequency fs to the measurement target frequency fc can be changed. For example, only one of the first measurement execution frequency fs ₁ and the second measurement execution frequency fs ₂ may be used. Alternatively, three or more measurement execution frequencies may be used. For example, the first adjustment frequency fd ₁ and the second adjustment frequency fd ₂ are set as the adjustment frequency fd, and the first adjustment frequency is set higher than the measurement target frequency fc. a first measurement run frequency _{fs 1-1} of fd ₁ only the low frequency side, a first measurement run frequency _{fs 1-2} of the than the measurement target frequency fc 2 adjusts the frequency fd ₂ only the low frequency side, measured frequency fc The second measurement execution frequency fs _2-1 on the high frequency side by the first adjustment frequency fd ₁ and the second measurement execution frequency fs _2-2 on the high frequency side by the second adjustment frequency fd ₂ from the measurement target frequency fc. May be used. Alternatively, when there are two or more frequency bands in which carrier sense is performed and transmission is performed by switching to any one of these, an adjustment frequency fd suitable for each frequency is set in advance and is suitable for a frequency used for transmission. The adjustment frequency fd may be selected to determine the measurement execution frequency fs.

(Selection of measurement execution frequency)
In the above embodiment, the maximum value of the first received signal strength Ls _{1 and} the maximum value of the second received signal strength Ls ₂ are selected from the first received signal strength Ls ₁ and the second received signal strength Ls ₂ measured a plurality of times. The received signal strength Lc is calculated by selecting each value, but other than the maximum value may be selected. For example, the first received signal strength Ls ₁ and the second received signal strength Ls ₂ measured multiple times. The received signal strength Lc may be calculated by selecting the average value of each.

(About modularization)
In the above embodiment, only the wireless transmission / reception unit 41 of the receiving device 40 is unitized, but the wireless transmission / reception unit 31 of the repeater 30 may be unitized by the same structure as the wireless transmission / reception unit 41. Alternatively, as with the wireless transmission / reception unit 31, the wireless transmission / reception unit 41 may be incorporated into the reception device 40 without being unitized.

DESCRIPTION OF SYMBOLS 1,100 Security system 2 Security sensor 3 Security terminal 10, 101 Opening / closing sensor 11, 102 Fire sensor 12, 103 Human sensor 13, 104 Abnormal alarm light 20 Portable setting apparatus 40a, 41a Case 22 Button group 22a Emergency button 22b Start button 22c Security button 22d Release button 23 Indicator light group 23a Emergency light 23b Warning light 23c OK light 23d NG light 23e Security light 23f Release light 24, 31, 41 Radio transceiver 24a, 35, 45 Antenna 25 Speakers 26, 32, 42 Storage unit 27, 33, 43 Power supply unit 28, 34, 44 Control unit 28a Signal processing unit 30, 105 Repeater 36, 46 Antenna side connection unit 37, 47 First signal processing unit 37a, 47a LPF
37b, 47b First basic processing unit 38, 48 Second signal processing unit 38a, 48a HPF
38b, 48b Second basic processing unit 38c, 48c Compatible processing unit 39, 49 Control unit side connection unit 40, 106 Receiver 40b Housing unit 40c Connection terminal

Claims (5)

A wireless device that receives a signal from a terminal device,
A wireless transceiver comprising an antenna;
A control unit that performs control based on the content of the signal received by the wireless transmission and reception unit,
The wireless transceiver unit is
Measure the received signal strength of each of a plurality of unit channels of a certain width included in a predetermined band, and based on the measured received signal strength, select an empty channel that is an empty unit channel among the plurality of unit channels. It has a carrier sense part to identify,
The carrier sense part is
Among the plurality of unit channels, the received signal strength of a measurement execution frequency that differs by a predetermined frequency is measured with respect to the measurement target frequency that is the center frequency of the unit channel that is the measurement target of the received signal strength, and the measured measurement Calculate the received signal strength of the measurement target frequency based on the received signal strength of the execution frequency, and identify an empty channel based on the calculated received signal strength.
Wireless device. The carrier sense part is
As the received signal strength of the measurement execution frequency, the received signal strength of the first measurement execution frequency that is lower than the measurement target frequency by the predetermined frequency and the higher frequency side of the measurement execution frequency by the predetermined frequency. 2 Measure the received signal strength at the measurement execution frequency,
Calculating the received signal strength of the measurement target frequency based on the measured received signal strength of the first measurement execution frequency and the received signal strength of the second measurement execution frequency;
The wireless device according to claim 1. The carrier sense part is
Measuring the received signal strength of the measurement execution frequency a plurality of times, and calculating the received signal strength of the measurement target frequency based on the maximum value of the received signal strength measured a plurality of times,
The wireless device according to claim 1 or 2. The control unit is accommodated in the first housing,
The wireless transceiver is provided in a second housing configured to be detachable from the first housing,
The radio | wireless apparatus as described in any one of Claim 1 to 3. The wireless device is a receiving device that receives a signal from a security sensor directly or via a disaster prevention repeater,
The radio | wireless apparatus as described in any one of Claim 1 to 4.

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