JP2013098906A - Radio communication device and radio communication network using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device connected to a radio communication network that uses a multi-hop function, capable of avoiding concentrated transmission of a status supervision signal of each self-device in a set time zone, and suppressing the occurrence of a transmission delay caused by network congestion if the number of radio communication devices transmitting status supervision signals increases.SOLUTION: The radio communication device receives a radio signal transmitted from another radio communication device, and transfers the received radio signal through the radio communication network. To transmit a status supervision signal indicative of the self-device status, the radio communication device selects a time for status supervision signal transmission from among a plurality of time settings capable of transmitting the status supervision signal in a predetermined second period (T2), using a random number, to transmit after the lapse of the selected time.

Description

  The present invention relates to a wireless communication device and a wireless communication network using the wireless communication device.

  2. Description of the Related Art Conventionally, a certain type of wireless communication network in which a plurality of wireless communication devices are interspersed and coupled by a wireless network has attracted attention. In this wireless communication network, wireless communication devices detect the presence of a wireless signal intermittently, and when a message is received from another wireless communication device, if the message is not addressed to itself, the same content message is transmitted. To do. That is, the wireless communication device functions as a transfer device. By repeating such transfer, the message is finally transmitted to the target wireless communication device. Such a communication function is called “multi-hop function”.

Alternatively, in the case of broadcast communication, when receiving a message from another wireless communication device, the wireless communication device captures the message as necessary and transfers a message having the same content. By repeating such transfer, the message is finally transmitted to all the wireless communication devices.
Each wireless communication device does not have communication path information and does not require a dedicated repeater. Therefore, it is possible to easily install each wireless communication device. Further, even when the processing speed of the communication control unit (CPU) of each wireless communication device is low, wireless communication is possible. Therefore, the scale of the wireless communication device is reduced, and the network can be constructed at a low cost as a whole.

JP 2011-114394 A

Recently, a simple installation type in which a wireless communication device has only to be connected to an external DC power source that is a drive source of the wireless communication device and installed at a predetermined place has been increasing. In addition to the external DC power supply, a battery using a battery has been devised instead of the external DC power supply.
In this case, it is necessary to notify the operator of a malfunction of the external DC power supply or a battery replacement time. For example, if a state monitoring signal indicating the battery consumption state of the own device (referred to as the first device) is transmitted to another wireless communication device, a display device connected to the first device and / or the other wireless communication device, etc. In this case, it is conceivable that the battery consumption state of the first unit is displayed, or if it is time to replace the battery, this is displayed in a particularly understandable manner.

However, in a wireless communication network using a multi-hop function, it takes time until convergence after one communication starts. In particular, as the number of slave units increases, the convergence time increases and may take several seconds.
Under such a wireless communication network, if you send a status monitoring signal that indicates the status of your device, such as battery exhaustion, the wireless line will be occupied, and you will not be able to send urgently necessary data during that time. Urgently necessary data cannot be received from other wireless communication devices. However, notification of the status monitoring signal is also important in terms of management of the wireless communication device, and when transmitting the status monitoring signal, it is necessary to devise in order to ensure that the transmission of the status monitoring signal is completed once. come.

  This is because if the transmission of the status monitoring signal collides with a plurality of wireless communication devices (the fact that the collision has occurred is detected by carrier sense), the transmission is resumed after waiting. If there are a large number of the status monitoring signal transmission timings overlapping in a plurality of wireless communication devices, the status monitoring signal transmission continues for a time of (waiting time) × (number of timings overlapping). For example, if the waiting time is 2.5 seconds and the number of overlapping timings is 30, the state monitoring signal transmission continues for a maximum of 75 seconds. This is because urgently necessary data communication opportunities are reduced. Such a problem is likely to occur when the transmission times of the state monitoring signals are set in the same cycle in a plurality of wireless communication devices.

  Patent Document 1 discloses that the intermittent reception intervals in all other radio stations are relatively shortened within a periodical reception period including before and after the time when a radio signal including a periodical monitoring message is transmitted from a set radio station. In the technology that can reliably receive the wireless signal, and can reduce power consumption by relatively increasing the intermittent reception interval in all other wireless stations outside the regular reception period. Although disclosed (see paragraph [0037] and the like of Patent Document 2), there is a possibility that a transmission delay occurs within a regular reception period as the number of slave stations increases. Further, when the intermittent reception interval is further shortened, power consumption increases.

  The present invention increases the number of wireless communication devices that transmit state monitoring signals without transmitting concentration of state monitoring signals in a set time zone in wireless communication devices connected to a wireless communication network that uses a multi-hop function. Even so, an object of the present invention is to provide a wireless communication device that can suppress the occurrence of transmission delay due to network congestion.

  The wireless communication device according to the present invention includes an information signal transmitting means for transmitting an information signal based on a command from the wireless communication device or a command from a connected external device, and a state in which a state monitoring signal indicating the state of the own device is transmitted. A monitoring signal transmitting means; a receiving means for receiving a wireless signal transmitted from another wireless communication device every elapse of a first period (T1); and a wireless signal received by the receiving means for receiving the wireless communication network And a communication control means, wherein the communication control means transmits the state monitoring signal during a predetermined second period (T2). The time for transmitting the state monitoring signal is arbitrarily selected from a plurality of set times that can be transmitted, and the state monitoring signal is transmitted when the time elapses. Interval between between (T3) is longer than the first period (T1).

According to the above-described wireless communication device, the state monitoring signal transmitting means transmits the state monitoring signal at an arbitrary time from among a plurality of set times, so that the plurality of wireless communication devices transmit the state monitoring signal. But I will not concentrate on the set time zone. Therefore, even if the number of wireless communication devices increases, it is possible to suppress the occurrence of transmission delay due to network congestion.
The wireless communication device of the present invention preferably further includes power supply means for supplying power by a battery and battery remaining amount detecting means for detecting the remaining amount of the battery. The “own device state” includes a state in which the state in which the remaining battery level detected by the remaining battery level detection unit is equal to or lower than a predetermined threshold value continues for a certain period. Even when the remaining battery level is equal to or lower than the threshold value, transmission is not performed immediately, but is performed when a state equal to or lower than the threshold value continues for a predetermined period, so that transmission due to erroneous detection can be prevented.

  Each of the communication control means may set the time for transmitting the state monitoring signal using a random number, and each of the wireless communication devices has a unique identification number, and the identification number of the own device is a radix. The random number may be used as In any case, since the period for transmitting the state monitoring signal spreads for each wireless communication device in the second period (T2), the transmission of the state monitoring signal does not concentrate on the set time zone. In particular, since the latter sets a random number based on the identification number of its own device, it is possible to eliminate the possibility that the values set by the random number overlap each other in each wireless communication device.

  The start time of the second period (T2) may be determined for each wireless communication device or may be determined uniformly for each wireless communication device connected to the wireless communication network. As a specific example, the former is a case where each second period (T2) is started when each wireless communication device is started up. The latter is a case where the same second period (T2) is started when the wireless communication devices are started up all at once.

When the state monitoring signal transmission unit recognizes a wireless signal from another wireless communication device by carrier sense at the time of transmitting the state monitoring signal, the state monitoring signal transmission unit transmits the state monitoring signal in a fourth period ( It is desirable to postpone by T4).
The wireless communication network of the present invention is a wireless communication network having the above-described wireless communication device as a constituent terminal.

It is a block diagram of the radio | wireless communication apparatus connected to a radio | wireless communication network. It is a flowchart for demonstrating the process which transmits the message which shows a power supply voltage fall after a power supply starting according to the result of a battery check. It is a flowchart which shows the process which transmits battery monitoring information. It is a flowchart which shows the transmission process which transmits battery monitoring information after the 2nd time. It is a graph which shows the time when battery monitoring information is transmitted from each wireless communication apparatus on a time axis.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
The present invention includes a wireless communication device and a wireless network that connects them. The wireless communication device basically has the same configuration. However, within a feasible range, each wireless communication device can have a different configuration, for example, a part of the wireless communication device may have a configuration dedicated to reception or a configuration dedicated to transmission. Moreover, although each radio | wireless communication apparatus demonstrates as a radio | wireless communication apparatus to move, the one part or all part may be attached to a fixed position.

  The frequency bands used in the wireless network are, for example, 400 MHz, 1.2 GHz, and 2.4 GHz frequency bands, but are not limited to this, and may be an infrared frequency band. Therefore, “wireless” in this specification includes infrared communication. In addition, the transmission power of the wireless communication device is a specific low power of about 1 to 10 mW. The communicable range of each wireless communication device is, for example, a range of about 200 m to 300 m.

  FIG. 1 is a block diagram of a wireless communication device. The wireless communication device includes a transmission / reception unit 101, a communication control unit 102, a power supply unit 103, a health check unit 104 that checks the function of the power supply unit 103, and an interface unit 105. Yes. The interface unit 105 is provided with contact input from an external device connected to the wireless communication device, contact output to the external device, and relay output. External devices connected to these contact inputs, contact outputs, and relay outputs include (A) various sensors, (B) rotating lights, signal lights, sound alarms, character display boards, and (C) wireless communication devices. There is a control controller or the like provided for the purpose of collecting the information in one place. These external devices are connected to a wireless communication device by wire or wireless.

  In addition, it is also possible to mount a part having functions of various sensors of (A) in a wireless communication device to be integrated. For example, a thermometer can be built in and a wireless communication device can be installed outdoors to send a message when the temperature reaches a predetermined temperature. In addition, an accelerometer may be built in the wireless communication device, and the wireless communication device may be installed on a slope of a mountain so that a message is transmitted when the wireless communication device falls due to a sediment disaster or the like.

  An example of using a wireless network to which a wireless communication device is connected is as follows: A beam sensor is installed in the exit passage of a parking lot, and the wireless communication device is controlled via a control box for controlling the beam sensor and controlling an audio alarm device. Connect to A contact input. A sound alarm is connected to the contact output of the other wireless communication device B. The beam sensor detects this when the vehicle leaves the parking lot, and is wirelessly transmitted from the wireless communication device A via the control box. When the wireless communication device B receives this wireless signal, the wireless communication device B outputs a predetermined contact output and announces from the sound alarm “The car comes out. Please be careful”. Since the wireless communication device A, the wireless communication device B, and the like are connected via a wireless line, the time and labor for system installation can be reduced.

The transmission / reception unit 101 includes a modulation unit, a power amplification unit, a high frequency amplification unit, a demodulation unit, and the like.
The communication control unit 102 is configured around a central processing unit (CPU), and its function is to execute a communication control program stored in the ROM while using the RAM which is a temporary storage area. The interface unit 105 employs asynchronous serial communication, for example. Note that the communication control unit 102, the ROM, the RAM, and the interface unit 105 may be mounted on one microcomputer chip.

  The communication control unit 102 receives intermittently periodically and has a transfer function for starting transfer of a message when a message is received from another wireless communication device through the wireless communication network. Here, “carrier sense” refers to a case where a certain time (starting from carrier sense) is used as a starting point (carrier sense starting point), waiting for a predetermined “waiting time”, and not being received from any wireless communication device within that waiting time. Refers to a technology that transmits (transfers) itself and does not transmit (transfer) itself when it recognizes that it has been transmitted (transferred) from another wireless communication device. In this way, messages are transferred from one to the next, and a message can be transmitted beyond the communicable distance of one wireless communication device. Here, “waiting time” refers to the time from the carrier sense starting point until it transmits a signal, and when it recognizes that transmission (transfer) from another wireless communication device was made within this waiting time, Do not send (transfer).

The power supply unit 103 may be a primary battery such as a dry battery, a secondary battery such as a lithium ion battery or a nickel cadmium battery, or a power adapter that converts AC electricity from a commercial power line into DC. Power from the power supply unit 103 is supplied to the transmission / reception unit 101, the communication control unit 102, and the like, and is also supplied to connected external devices as necessary.
The health check unit 104, which is a part of the communication control unit 102, measures the power supply capability of the power supply unit 103, specifically the terminal voltage of the power supply unit 103, and when the voltage drops below the threshold, A message is generated and wirelessly transmitted through the communication control unit 102. The “threshold value” is a threshold value for prompting the replacement of the battery or the inspection of the power adapter because the operation of the wireless communication device becomes unstable when the threshold value is lowered. Hereinafter, assuming that the power supply unit 103 is a battery, checking the power supply capability of the power supply unit 103 is referred to as “battery check”.

FIG. 2 is a flowchart illustrating the entire process of transmitting a message indicating that the battery check and the voltage are lower than the threshold when the wireless communication device is activated, which is performed by the health check unit 104 and the communication control unit 102. is there.
When the power source of the wireless communication device is activated, the health check unit 104 performs a battery check, and when detecting that the voltage is lower than the threshold value, sets a low battery flag (steps S1 to S3). Then, the wireless communication device transmits information on participation in the wireless communication network. If the low battery flag is set at this time, it is transmitted simultaneously as battery monitoring information (step S4). As shown in FIG. 3, the detailed content of this transmission process is determined whether or not the low battery flag is set (step S41). If the low battery flag is set, the low battery is set (step S42), and wireless communication is performed. Transmission is performed with the identification number of the device (step S43). When the transmission is completed, the low battery flag is cleared (step S44). Note that the low battery flag may not be lowered. This is because once the low battery flag is set, the battery check is always below the threshold in subsequent battery checks, and the low battery flag is set again.

The above processing is processing performed when the power source of the wireless communication device is activated.
After activation, a time for transmitting the battery monitoring information in the day is set by a random number (step S5). For example, one day is divided into 24 hours, 0:00 to 1 o'clock is the first time, 1 o'clock to 2 o'clock is the second time, ... 23:00 to 24 o'clock is the 24th hour. Among them, the time for transmitting the battery monitoring information is determined using random number generation software. The “one day” is a relative time counted from when the power source of the wireless communication device is activated.

When the time to be transmitted is determined, the process proceeds to the counting process of FIG.
In the process of FIG. 4, first, a battery check is performed (step S60), and it is determined whether the voltage is equal to or lower than a threshold value (step S61). If the voltage is less than or equal to the threshold, the “current time array flag” is set to Hi (step S62), and if the voltage exceeds the threshold, the “current time array flag” is set to low (step S63). This “current time array flag” is a flag for determining whether or not to set in accordance with the voltage every hour.

  If the “current time array flag” has been set continuously m times (m = 6 in this example) in the past (step S64), the voltage has dropped below the threshold value for the first time (low battery). Is judged. The battery check is performed a plurality of times in this way because the power supply capability of the power supply unit 103 remains in the single check, but the voltage may happen to be measured lower than the threshold at the time of measurement. It is. Moreover, even if the voltage drops below the threshold, the power supply capability of the power supply unit 103 still remains for m hours. The value of m should be set from the viewpoint of the remaining capacity of the battery.

Thus, after the state where the voltage is lower than the threshold value continues for m hours, it is determined that the power supply unit 103 has insufficient power supply capacity for the first time, and a low battery flag is set (step S65).
Next, the elapse of time is counted, and when 1 hour elapses, the count value is advanced by 1 (step S66). If the “current time array flag” is set to Low in step S63, and the “current time array flag” has not been set in the past m times in step S64, the count value is similarly incremented by one. (Step S67).

  Next, it is determined whether or not the count value has reached the time set in step S5 (time when battery monitoring information should be transmitted within "one day") (step S67). Enter (step S68). The content of this transmission process is almost the same as the process described with reference to FIG. 3 (steps S41 to S44). In addition, how many hours or how many days have passed since the low battery flag was set for the first time. A value indicating is also transmitted.

Then, it is checked whether or not the count value advanced in step S66 is the 24th time (step S69), and if it is not the 24th time, the process returns to step S60. At the 24th time, it is determined that the “day” has ended, the count value is set to 0 (step S70), and the time for transmitting the battery monitoring information is again determined based on the random number (step S71).
As described above, the time for transmitting the battery monitoring information is arbitrarily set using a random number in “one day”, and the “time to transmit” has elapsed from the beginning of “one day”. Then, the battery monitoring information is transmitted.

  Here, “one day” is the time that has elapsed since the power of the wireless communication device was activated. Therefore, (1) if the time at which the power of the wireless communication device is activated varies, “one day” The beginning of "is also mixed. However, (2) the start time of “one day” when the power of the wireless communication device is activated may be unified. This can occur when the power supply units 103 are supplied from a common battery, or are supplied from a common power supply adapter, and the wireless communication devices are turned on all at once.

  According to the present embodiment, the time for transmitting the battery monitoring information is arbitrarily set using a random number in “one day”, and the “time to transmit” has elapsed from the beginning of “one day”. Thus, since the battery monitoring information is transmitted, even if the start of “one day” is unified in each wireless communication device as described in (2) above, the battery monitoring information output from the wireless communication device is not The probability of collision is small. In the case of the above (1), since the start of “one day” is not unified in each wireless communication device, the probability that the battery monitoring information issued from the wireless communication device will collide further decreases.

  However, in either case (1) or (2) described above, it cannot be said that there is no possibility that the battery monitoring information issued from each wireless communication device will collide during the “day”. In preparation for such a collision case, the carrier-sensed wireless communication device recognizes that transmission from another wireless communication device has been performed, waits for a predetermined transfer waiting time without transferring itself, It is desirable to perform carrier sense again after the transfer waiting time has elapsed. If this “transfer waiting time” is set to be constant for all wireless communication devices, there is a possibility that the carrier sense time will be duplicated again and the simultaneous transfer state may be fixed. In order to cause variation, it is preferable to add a random time to the “transfer waiting time”. This additional time may also be set with random number generation software for each wireless communication device. Here, the “transfer waiting time” refers to the time from when recognizing transmission from another wireless communication device by carrier sense until it retransmits itself. In the embodiment of the present invention, if the battery monitoring information cannot be transmitted even after a plurality of retries, it is transmitted on the next “one day”, that is, the next day.

  In addition, as a countermeasure against collision of battery monitoring information, a unique identification number is assigned to each wireless communication device at the time of manufacturing the wireless communication device, and each random number generation software sets the random number based on the identification number of the own device. It may be. According to this, since the identification numbers of the respective wireless communication devices are different from each other, the same number is not obtained as a result of adding a random number thereto. Therefore, there is no possibility of collision of battery monitoring information.

Thus, the battery monitoring information sent from each wireless communication device is illustrated on the time axis as a result of arbitrarily setting the time at which the battery monitoring information should be transmitted using “random numbers” in “one day”. The graph is shown in FIG. However, in FIG. 5, the graph is drawn on the assumption that the start of “one day” is unified in each wireless communication device, as described in (2) above.
In FIG. 5, the time interval of intermittent reception is indicated by “T1”, “one day” is indicated by “T2”, the battery monitoring information is indicated by an upward arrow, and the interval between times at which the battery monitoring information should be transmitted ( That is, 1 hour) is indicated by “T3”.

  In FIG. 5, it is assumed that there are eight wireless communication devices, and the nth wireless communication device is represented by “Txn”. The wireless communication device Tx1 sets the second time as the time for transmitting the battery monitoring information. The wireless communication device Tx2 sets the eighth time as the time for transmitting the battery monitoring information. The wireless communication device Tx3 sets the 23rd time as the time for transmitting the battery monitoring information. The wireless communication device Tx7 sets the eighth time as the time for transmitting the battery monitoring information, and the wireless communication device Tx8 sets the eleventh time as the time for transmitting the battery monitoring information.

  As described above, since the time for transmitting the battery monitoring information is arbitrarily set using the random number in the day T2, the probability that the times for transmitting the battery monitoring information overlap is reduced. However, as in the case of the wireless communication device Tx2 and the wireless communication device Tx7, the eighth time set as the time for transmitting the battery monitoring information may overlap. In this case, since the wireless communication device, for example, Tx7, which later tried to transmit the battery monitoring information recognizes the transmission from the wireless communication device Tx2, it waits for a predetermined transfer waiting time without performing the transfer, The carrier sense is performed again after the standby time has elapsed. This transfer standby time is displayed as “T4” on the time axis of the wireless communication device Tx7 in FIG.

  In the embodiments described so far, a period T2 of “one day” is first set with reference to the human activity cycle, and is divided into 24 hours, with 0:00 to 1:00 being the first time, and 1 to 2 The time is set as the second time, and 23:00 to 24:00 is set as the 24th time, in which the time for transmitting the battery monitoring information is specified. The period T2 serving as a basis for specifying the time for transmitting the battery monitoring information is not limited to “one day”. A period longer than one day, for example, one month may be set, or a period shorter than one day, for example, one hour may be set.

  In addition, the time for transmitting the battery monitoring information is divided every T3 = 1 hour, and the battery monitoring information is transmitted at any one of these times. It is not limited to “1 hour”. You may set to a period shorter than 1 hour, for example, 1 minute. However, it should not be shorter than the period T1 for intermittent reception. This is because the battery monitoring information may not be transmitted if it is shorter than the intermittent reception cycle T1.

  In the embodiments described so far, the battery monitoring information as a result of checking the function of the power supply unit 103 is transmitted. However, in addition to the battery monitoring information, the present invention is applicable if a status monitoring signal indicating the status of the own device is transmitted. For example, there is low battery count information that stores the count value from the time when the low battery flag is first set and indicates how many hours or how many days the low battery state has continued.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

101 Transmission / Reception Unit 102 Communication Control Unit 103 Power Supply Unit 104 Health Check Unit 105 Interface Unit

Claims (9)

A wireless communication device connected to a wireless communication network,
Information signal transmission means for transmitting an information signal based on a command from the wireless communication device or a command from a connected external device;
State monitoring signal transmitting means for transmitting a state monitoring signal indicating the state of the own machine;
Receiving means for receiving a wireless signal transmitted from another wireless communication device for each elapse of the first period (T1);
Transfer means for transferring the wireless signal received by the receiving means through the wireless communication network;
Communication control means,
The communication control means may arbitrarily set a time for transmitting the state monitoring signal from a plurality of set times during which the state monitoring signal can be transmitted within a predetermined second period (T2). The state monitoring signal is transmitted as time passes,
The plurality of set time intervals (T3) are longer than the first period (T1), the wireless communication device.   The battery further includes power supply means for supplying power by a battery and battery remaining amount detecting means for detecting the remaining amount of the battery, and the “state of the own device” is detected by the remaining battery amount detecting means. The wireless communication device according to claim 1, wherein the state in which the remaining amount of the battery is equal to or less than a predetermined threshold is included for a certain period.   The wireless communication device according to claim 1, wherein the communication control unit sets a time for transmitting the state monitoring signal using a random number.   The wireless communication device according to claim 3, wherein the wireless communication device has a unique identification number and uses the random number based on the identification number of the own device.   When the state monitoring signal transmission unit recognizes a wireless signal from another wireless communication device by carrier sense at the time of transmitting the state monitoring signal, the state monitoring signal transmission unit transmits the state monitoring signal in a fourth period ( The wireless communication device according to any one of claims 1 to 4, wherein the wireless communication device is postponed by T4).   The wireless communication device according to claim 5, wherein the communication control unit sets the fourth period (T4) using a random number.   The wireless communication device according to any one of claims 1 to 6, wherein a start time of the second period (T2) is determined for each wireless communication device.   The wireless communication device according to any one of claims 1 to 6, wherein a start time of the second period (T2) is uniformly determined for each wireless communication device connected to the wireless communication network. . A wireless communication network for connecting a plurality of wireless communication devices,
A wireless communication network including the wireless communication device according to claim 1 as a constituent terminal.

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