WO2011007567A1 - 無線通信装置、無線通信システム、および無線通信方法、並びにこの無線通信方法を実行させるプログラム - Google Patents
無線通信装置、無線通信システム、および無線通信方法、並びにこの無線通信方法を実行させるプログラム Download PDFInfo
- Publication number
- WO2011007567A1 WO2011007567A1 PCT/JP2010/004582 JP2010004582W WO2011007567A1 WO 2011007567 A1 WO2011007567 A1 WO 2011007567A1 JP 2010004582 W JP2010004582 W JP 2010004582W WO 2011007567 A1 WO2011007567 A1 WO 2011007567A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- wireless communication
- beacon signal
- beacon
- communication device
- reception
- Prior art date
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W48/00—Access restriction; Network selection; Access point selection
- H04W48/08—Access restriction or access information delivery, e.g. discovery data delivery
- H04W48/10—Access restriction or access information delivery, e.g. discovery data delivery using broadcasted information
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
- H04W56/0015—Synchronization between nodes one node acting as a reference for the others
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/02—Power saving arrangements
- H04W52/0209—Power saving arrangements in terminal devices
- H04W52/0212—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave
- H04W52/0216—Power saving arrangements in terminal devices managed by the network, e.g. network or access point is master and terminal is slave using a pre-established activity schedule, e.g. traffic indication frame
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Definitions
- the present invention relates to a wireless communication device, a wireless communication system, a wireless communication method, and a program for executing the wireless communication method, and in particular, by transmitting and receiving a beacon signal between a plurality of wireless communication devices.
- the present invention relates to a wireless communication apparatus, a wireless communication system, a wireless communication method, and a program for executing the wireless communication method, for synchronizing the time of the apparatus.
- a wireless communication system various forms such as a wireless LAN, mobile communication, a private wireless communication network, a radio for transportation, and a disaster prevention administrative wireless network have been developed and put into practical use.
- a new wireless communication system for example, a meter wireless meter reading system that measures the amount of usage by communicating with a meter such as gas, water, and electric power has been proposed.
- a beacon signal is transmitted and received between a plurality of wireless communication devices constituting the wireless communication system. Since synchronization is established between the wireless communication devices by transmitting and receiving beacon signals, the timing of transmitting and receiving various data can be controlled.
- This wireless communication system is a technology related to a wireless LAN, and includes a wireless access point having a built-in radio clock circuit and a wireless communication terminal.
- the wireless access point receives a standard radio wave transmitted from a standard radio wave transmission station, acquires time data of standard time, and based on the standard time data, the time synchronized with the standard time is used as a base point at intervals of 100 ms.
- Send a beacon signal Based on the acquired standard time data, the wireless communication terminal performs intermittent reception in synchronization with the time of the beacon signal transmitted by the wireless access point, and receives the beacon signal.
- this wireless communication system there are a plurality of wireless access points, and since all wireless access points are synchronized with the standard time, a beacon signal is transmitted at the same timing. Therefore, when the wireless communication terminal moves out of the communication area of a certain wireless access point A, the wireless communication terminal cannot receive the beacon signal of the wireless access point A, but does not shift to the continuous reception operation, and continues to standard The intermittent reception is continued at the intermittent reception timing synchronized with the time.
- the radio access point B transmits a beacon signal at the same timing as the radio access point A. Therefore, if the wireless communication terminal moves within the range of the wireless access point B, the beacon signal of the wireless access point B can be received.
- a technique capable of coping with an interference signal such as an automatic meter reading system disclosed in Patent Document 2
- This automatic meter reading system is a technology related to an automatic meter reading system for a flow meter such as a gas meter, a water meter, and an electric power meter, and a first wireless communication device that acquires a meter reading value measured by the flow meter, and the first wireless communication device. And a second wireless communication device that receives meter reading data from the communication device.
- the first and second wireless communication devices adopt an intermittent operation method in order to reduce current consumption.
- the synchronization of the intermittent operation timing is performed by transmitting and receiving a synchronization signal between these wireless communication devices.
- the wireless communication device is configured to detect that a jamming signal has been generated by the carrier detection means and perform control to change the intermittent operation timing as necessary.
- the conventional technique has a problem that it cannot sufficiently cope with a situation of a collision of beacon signals in order to synchronize time among a plurality of wireless communication devices.
- beacon transmission terminal a wireless communication device on the side that transmits a beacon
- a wireless communication device on the side that receives a beacon is referred to as a “beacon reception terminal”.
- beacon reception terminal a wireless communication device on the side that receives a beacon
- a plurality of beacon transmitting terminals wireless access points
- the wireless communication system is configured to fix the position of the beacon receiving terminal and move the beacon transmitting terminal, the risk that each beacon signal collides increases as a plurality of beacon transmitting terminals move. To do.
- Patent Document 2 is based on the premise that the presence of a disturbing signal is short. Therefore, by shifting the transmission / reception operation timing, the synchronization signal is received at any one of the multiple reception timings, but when collisions between multiple beacon signals occur for a relatively long time I can not cope.
- a beacon receiving terminal is provided with a standard radio clock function in order to avoid collision of beacon signals, as described above, the circuit scale increases and the cost increases.
- the present invention has been made to solve such a problem, and in a wireless communication system, even when beacon signals are transmitted from a plurality of wireless communication devices, a beacon signal is suppressed without increasing cost. It is an object of the present invention to provide a technique capable of effectively avoiding the collision.
- a wireless communication device configured to perform wireless communication and a communication control unit that controls operation timing of the wireless communication unit in order to intermittently communicate the beacon signal.
- the beacon signal is configured to transmit a first beacon signal and a second beacon signal, and the communication control unit transmits the first beacon signal with a preset timing pattern P1.
- the standby time Q which is a time shorter than the timing pattern P1
- the communication control unit transmits the first beacon signal with a preset timing pattern P1.
- the wireless communication device is configured to receive the first beacon signal and the second beacon signal, and the communication control unit is configured to receive the first beacon signal in advance.
- a delay time R that is shorter than the waiting time Q after the waiting time Q that is shorter than the timing pattern P2 has elapsed.
- a configuration for controlling the operation of the wireless communication unit is also included so as to make a trial according to the above.
- the wireless communication system according to the present invention includes the wireless communication device having the above configuration as a communication terminal.
- the wireless communication method includes a wireless communication device that intermittently transmits a beacon signal as a parent wireless terminal, and the wireless communication device that intermittently receives the beacon signal.
- a wireless communication method used in a wireless communication system wherein the first beacon signal is transmitted from the parent wireless terminal with a preset timing pattern P1, and the child
- the step of trying to receive the first beacon signal with a preset timing pattern P2 and the standby from the parent wireless terminal for the second beacon signal that is shorter than the timing pattern P1.
- the reception of the second beacon signal is matched with the lapse of the delay time R that is shorter than the waiting time Q after the waiting time Q that is shorter than the timing pattern P2 has elapsed.
- the step of trying is a wireless communication method used in a wireless communication system, wherein the first beacon signal is transmitted from the parent wireless terminal with a preset timing pattern P1, and
- the program for executing the wireless communication method according to the present invention includes a wireless communication device that transmits a beacon signal as a parent wireless terminal, and a wireless communication device that receives the beacon signal as a child wireless terminal.
- a program described in a computer-readable format so as to execute transmission / reception processing of the beacon signal on a computer included in the wireless communication device, wherein the beacon signal includes a first beacon signal and a second beacon signal.
- the wireless communication device is configured such that beacon signals are transmitted and received intermittently, and the wireless communication device is the parent wireless terminal, the first beacon signal is set to a preset timing pattern P1.
- the second beacon signal shorter than the timing pattern P1 A delay time R, which is shorter than the waiting time Q, and a transmission step when the delay time R is shorter than the waiting time Q. If there is a waiting time Q that is a time shorter than the timing pattern P2, the step of trying to receive the first beacon signal with a preset timing pattern P2 and the reception of the second beacon signal. After the elapse of time, the computer is configured to execute the step of trying in accordance with the elapse of the delay time R that is shorter than the waiting time Q.
- beacon signals are transmitted from a plurality of wireless communication devices in a wireless communication system, it is possible to effectively avoid a collision of beacon signals while suppressing an increase in cost. There is an effect.
- FIG. 2 is a block diagram illustrating an example of a configuration of a main part of a radio communication device used in the radio communication system illustrated in FIG. 1, which is a beacon transmission-side radio communication device according to Embodiment 1 of the present invention.
- FIG. 2 is a block diagram illustrating an example of a configuration of a main part of a radio communication device used in the radio communication system illustrated in FIG. 1, which is a beacon reception-side radio communication device according to Embodiment 1 of the present invention.
- FIG. 4C is a schematic diagram illustrating an example of a signal format of a polling signal or a slave unit call signal
- FIG. 8C is a schematic diagram illustrating an example of components of a repetitive header included in the signal format illustrated in FIG. .
- (A) is a time chart which shows an example of periodic transmission of a beacon signal in the beacon transmission side wireless communication apparatus shown in FIG. 2, and (b) is a beacon transmission side wireless communication apparatus shown in FIG. It is a schematic diagram which shows the relationship between the timing which transmits transmission, and the timing which the beacon receiving side radio
- (c) is a signal of the beacon signal shown in FIG. 5 (a). It is a schematic diagram explaining the relationship with the reception timing of the beacon signal with respect to a format.
- FIG. 10 is a block diagram illustrating an example of a configuration of a main part of a radio communication device used in the radio communication system illustrated in FIG. 9, which is a beacon reception-side radio communication device according to Embodiment 2 of the present invention.
- a wireless communication apparatus is used in a wireless communication system including a plurality of wireless communication apparatuses that communicate beacon signals with each other, and is configured to perform at least one of transmission and reception of the beacon signal.
- a communication control unit that controls operation timing of the wireless communication unit in order to intermittently communicate the beacon signal, wherein the first beacon signal is The communication control unit is configured to transmit a beacon signal and a second beacon signal, and the communication control unit causes the first beacon signal to be transmitted in a preset timing pattern P1, and the second beacon signal is A delay that is shorter than the waiting time Q after the waiting time Q that is shorter than the timing pattern P1 has elapsed. As to transmit during the same time when R has elapsed, and is configured to control operation of the wireless communication unit.
- the wireless communication device further includes a clock unit that periodically generates a timing pulse that defines a time interval, and the first beacon signal and the second beacon signal are between the other wireless communication devices, It is preferable that the configuration be used for control to synchronize the operations of the clock units.
- the wireless communication device having the above configuration is configured to receive the first beacon signal and the second beacon signal, and the communication control unit is configured to receive the first beacon signal at a preset timing.
- the second beacon signal is received in accordance with the elapse of the delay time R, which is shorter than the waiting time Q after the waiting time Q, which is shorter than the timing pattern P2, elapses. It is preferable that the operation of the wireless communication unit is controlled so as to try.
- the communication control unit may determine that the timing pattern P1 or P2 is a periodic pattern in which the timing of each transmission / reception is a constant cycle or the timing of each transmission / reception is not a constant cycle Any configuration may be used as long as it is set as a random pattern.
- the standby time Q is a set value that is set in advance as a predetermined length
- the delay time R may be a random value whose length can be changed.
- the second beacon signal only needs to include information indicating the length of the delay time R.
- the communication control unit is an integral multiple of a cycle in which the first beacon signal is transmitted from the other wireless communication device.
- the operation of the wireless communication unit is controlled so that the reception of the first beacon signal is attempted in a cycle and the second beacon signal is received only when the reception of the first beacon signal is not successful. I just need it.
- the communication control unit causes the wireless communication unit to attempt to receive the first beacon signal and the second beacon signal within a preset reception trial upper limit time.
- the operation of the wireless communication unit is controlled, and the reception trial upper limit time is different between a case where the reception of the first beacon signal is attempted and a case where the reception of the second beacon signal is attempted. Any configuration may be used.
- the wireless communication system only needs to include the wireless communication device having the above-described configuration as a communication terminal.
- the wireless that transmits the first beacon signal and the second beacon signal is a parent wireless terminal that collects data, and the wireless communication device that receives the first beacon signal and the second beacon signal acquires data to be transmitted to the parent wireless terminal. Is preferable.
- the first beacon signal and the second beacon signal transmitted from the parent wireless terminal are received, and the first beacon signal and the second beacon signal are transmitted to the child wireless terminal.
- the wireless communication device to be transmitted may be a relay wireless terminal that relays communication between the parent wireless terminal and the child wireless terminal.
- the child wireless terminal further includes a flow rate acquisition unit that acquires the flow rate data from a flowmeter that measures the flow rate of fluid, and the parent wireless terminal receives the flow rate from the child wireless terminal.
- the configuration may further include a flow rate collecting unit that receives and collects data.
- the wireless communication method includes a wireless communication device that intermittently transmits a beacon signal as a parent wireless terminal, and a wireless communication device that intermittently receives the beacon signal as a child wireless terminal.
- a wireless communication method used in a wireless communication system comprising: transmitting a first beacon signal from the parent wireless terminal in a preset timing pattern P1; and in the child wireless terminal, the first beacon signal And receiving the second beacon signal from the parent wireless terminal after a waiting time Q, which is shorter than the timing pattern P1, has elapsed, from the parent wireless terminal.
- the program for executing the wireless communication method according to the present invention includes a wireless communication device that transmits a beacon signal as a parent wireless terminal, and a wireless communication device that receives the beacon signal as a child wireless terminal.
- a program described in a computer-readable format so as to execute transmission / reception processing of the beacon signal on a computer included in the wireless communication device, wherein the beacon signal includes a first beacon signal and a second beacon signal.
- the wireless communication device is configured such that beacon signals are transmitted and received intermittently, and the wireless communication device is the parent wireless terminal, the first beacon signal is set to a preset timing pattern P1.
- the second beacon signal shorter than the timing pattern P1 A delay time R, which is shorter than the waiting time Q, and a transmission step when the delay time R is shorter than the waiting time Q. If there is a waiting time Q that is a time shorter than the timing pattern P2, the step of trying to receive the first beacon signal with a preset timing pattern P2 and the reception of the second beacon signal. After the elapse of time, the computer is configured to execute the step of trying in accordance with the elapse of the delay time R that is shorter than the waiting time Q.
- the wireless communication system according to Embodiment 1 of the present invention is a short-range wireless communication network including a parent wireless terminal, a relay wireless terminal, and a child wireless terminal as a wireless communication apparatus according to the present invention.
- a radio communication system and a radio communication apparatus according to the present embodiment will be specifically described with reference to the drawings.
- the radio communication system As shown in FIG. 1, the radio communication system according to the present embodiment has a master radio terminal 101, relay radio terminals 111, 121, and 131 and child radio terminals 102 to 104, 112 to 114, and 122 to as radio communication devices. 124 is included.
- the configuration of the radio communication system is not limited to this.
- These wireless communication devices may be included in excess of the number shown, or may be less than the number shown.
- the parent wireless terminal 101 and the relay wireless terminals 111, 121, and 131 are wireless communication apparatuses on the side transmitting beacon signals (referred to as beacon transmission side wireless communication apparatuses for convenience), as will be described later. Further, as will be described later, the child wireless terminals 102 to 104, 112 to 114, and 122 to 124 are wireless communication devices on the side of receiving beacon signals (referred to as beacon receiving side wireless communication devices for convenience). Further, the relay wireless terminals 111, 121, 131 are also beacon receiving side wireless communication apparatuses. Therefore, the relay wireless terminals 111, 121, and 131 are wireless communication devices that can transmit and receive beacon signals.
- the master wireless terminal 101 can transmit a beacon signal to each of the child wireless terminals 102 to 104 and the relay wireless terminal 111, and wirelessly transmits data between the child wireless terminals 102 to 104 and the relay wireless terminal 111, respectively. Communication is possible. Therefore, in FIG. 1, these wireless communication apparatuses are connected by a bidirectional dotted arrow.
- the parent wireless terminal 101, the child wireless terminals 102 to 104, and the relay wireless terminal 111 constitute a first layer network of the wireless communication system.
- the relay wireless terminal 111 can transmit a beacon signal to each of the child wireless terminals 112 to 114 and the relay wireless terminal 121, and performs data communication with each of the child wireless terminals 112 to 114 and the relay wireless terminal 121. Is possible. Therefore, the relay wireless terminal 111 becomes a “child wireless terminal” in a broad sense when viewed from the parent wireless terminal 101, but becomes a “parent wireless terminal” in a broad sense when viewed from the child wireless terminals 112 to 114 and the relay wireless terminal 121. Therefore, the relay wireless terminal 111, the child wireless terminals 112 to 114, and the relay wireless terminal 121 constitute a second layer network of the wireless communication system.
- the relay radio terminal 121 can transmit beacon signals to the child radio terminals 122 to 124 and the relay radio terminal 131 and performs data communication with the child radio terminals 122 to 124 and the relay radio terminal 131, respectively. Is possible. Therefore, the relay wireless terminal 121 becomes a “child wireless terminal” in a broad sense when viewed from the relay wireless terminal 111, but becomes a “parent wireless terminal” in a broad sense when viewed from the child wireless terminals 122 to 124 and the relay wireless terminal 131. Therefore, the relay wireless terminal 121, the child wireless terminals 122 to 124, and the relay wireless terminal 131 constitute a third layer network of the wireless communication system.
- the relay wireless terminal 131 can transmit beacon signals to a plurality of child wireless terminals and relay wireless terminals (not shown) or a plurality of child wireless terminals, and can perform data communication with these wireless communication devices. It has become. Therefore, the relay radio terminal 131 and the child radio terminal and relay radio terminal not shown constitute the fourth layer network of the radio communication system, and the relay radio terminal not shown is defined as a “parent radio terminal” in a broad sense. Subsequent networks in the fifth layer can be formed. If the relay wireless terminal is not included in the fourth layer network, the wireless communication system shown in FIG. 1 is configured only by the first to fourth layer networks.
- a broader “child wireless terminal” wireless communication apparatus belonging to a network constituting the same hierarchy
- the clock section of the broader “child radio terminal” can be synchronized with the clock section of the broader “parent radio terminal”.
- each “child radio terminal” in the broad sense receives the beacon signal intermittently at the timing when the broad “parent radio terminal” transmits the beacon signal, and at the timing when the beacon signal is received. Call communication can be performed.
- parent wireless terminal 101 In the present embodiment, parent wireless terminal 101, relay wireless terminals 111, 121, and 131 and child wireless terminals 102 to 104, 112 to 114, and 122 to 124 are the parent station, relay station, and child of the short-range wireless communication network, respectively. These stations are further connected to information terminals such as personal computers, printers, scanners, and servers.
- each of the wireless communication devices described above is a wireless communication device according to the present embodiment, and these are specifically described with reference to FIG. 2 and FIG. 3, focusing on the configuration related to transmission / reception of beacon signals.
- FIG. 2 and FIG. 3 focusing on the configuration related to transmission / reception of beacon signals.
- the parent wireless terminal 101 and the relay wireless terminals 111, 121, and 131 correspond to the broader “parent wireless terminal”, but these broader “parent wireless terminals” transmit beacon signals as shown in FIG.
- the wireless communication device 30A has a function of transmitting to a “child wireless terminal” in a broad sense.
- the wireless communication device 30A is referred to as a beacon transmission side wireless communication device 30A.
- the beacon transmission side wireless communication device 30A includes a wireless communication unit 31, a beacon timing control unit 32, a slot control unit 33, and a clock unit 34 as main components related to wireless communication.
- the wireless communication unit 31 includes an antenna 311, a transmission / reception unit 312, a beacon generation unit 313, a polling communication unit 314, and a slave unit call communication unit 315.
- the beacon transmission side wireless communication device 30A has various configurations for functioning as a master station (base station) of the short-range wireless communication network.
- the wireless communication unit 31 performs wireless communication with a “child wireless terminal” in a broad sense, and is particularly configured to transmit a beacon signal.
- the antenna 311 constituting the wireless communication unit 31 is not particularly limited as long as it can transmit and receive radio waves in a predetermined band.
- a short-range wireless communication network such as IEEE 802.15.4 or the like.
- a known antenna capable of transmitting and receiving radio waves in a band defined by the standard is used.
- the transmission / reception unit 312 modulates a data signal into a signal of a predetermined band, or transmits a signal of a predetermined band as data in order to transmit a radio wave from the antenna 311 to the air or receive a radio wave transmitted through the air.
- a high-frequency circuit (RF) that demodulates signals.
- the specific configuration is not particularly limited, and an RF circuit known in the art is used in the short-range wireless communication network.
- the beacon generation unit 313 generates a beacon signal and outputs the beacon signal to the transmission / reception unit 312, and the beacon signal generation and output timing is controlled by the beacon timing control unit 32 as described later.
- the specific configuration of the beacon generation unit 313 is not particularly limited, and a known wireless communication circuit that can generate a beacon signal is used. As will be described later, in the present invention, not only one type of beacon signal but two types are generated.
- the polling communication unit 314 generates a polling signal and outputs the polling signal to the transmission / reception unit 312 in order to perform polling communication with the “child radio terminal” in a broad sense, and also receives a signal received from the “child radio terminal” in a broad sense. This is acquired from the transmission / reception unit 312.
- the specific configuration is not particularly limited, and a wireless communication circuit known in the field of polling communication is used.
- the slave unit call communication unit 315 generates a slave unit call signal for the broadly defined “slave radio terminal” and outputs the slave unit call signal to the transmission / reception unit 312.
- the transmitted connection permission signal is acquired from the transmission / reception unit 312.
- the specific configuration is not particularly limited, and a wireless communication circuit known in the field of handset call communication is used.
- the wireless communication unit 31 may have a configuration other than the above-described functional units.
- the functional units may be configured as individual circuits, but may be combined into a single circuit board or integrated circuit.
- the beacon timing control unit 32 controls the timing of beacon signal generation by the beacon generation unit 313 and the output of the beacon signal to the transmission / reception unit 312. Therefore, the beacon timing control unit 32 controls the transmission timing of the beacon signal from the beacon transmission side wireless communication device 30A. Note that the beacon timing control unit 32 may operate constantly, but in the present embodiment, the beacon timing control unit 32 is configured to be activated in accordance with the timing of transmitting a beacon signal under the control of the slot control unit 33.
- the slot control unit 33 generates time slots assigned to data frames transmitted and received by the wireless communication unit 31 and performs timing control thereof, and also performs operation control of the wireless communication unit 31 and the beacon timing control unit 32. Further, as apparent from FIG. 2, the slot control unit 33 controls the operation of the beacon timing control unit 32, thereby indirectly controlling the operation of the beacon generation unit 313.
- the beacon timing control unit 32 and the slot control unit 33 operate according to a program stored in a storage unit (not shown) by a CPU (not shown) as a calculation unit provided in the beacon transmission side wireless communication device 30A.
- a CPU not shown
- the present invention is not limited to this, and may be configured as a logic circuit using a known switching element, subtractor, comparator, or the like.
- the beacon timing control unit 32 and the slot control unit 33 collectively constitute a “communication control unit”. Become. Therefore, the beacon timing control unit 32 and the slot control unit 33 may constitute a “communication control unit” as an integrated single functional unit. Further, the configuration of the “communication control unit” is not limited to the combination of the beacon timing control unit 32 and the slot control unit 33, and may include other functional configurations in accordance with the specific configuration of the beacon transmission side wireless communication device 30A. Good.
- the clock unit 34 periodically generates timing pulses that define time intervals.
- the slot control unit 33 operates in accordance with this timing pulse.
- each functional unit configuring the wireless communication unit 31 also operates in accordance with the timing pulse of the clock unit 34.
- As the clock unit 34 a known clock oscillation circuit is used.
- the child wireless terminals 102 to 104, 112 to 114, 122 to 124 and the relay wireless terminals 111, 121, and 131 correspond to the broadly defined “child wireless terminals”.
- the wireless communication device 40A has a function of receiving a beacon signal from a “parent wireless terminal” in a broad sense.
- the wireless communication device 40A is referred to as a beacon receiving-side wireless communication device 40A.
- the beacon receiving-side radio communication device 40A includes a radio communication unit 41, a beacon timing control unit 42, a slot control unit 43, a clock unit 44, and a time synchronization unit 45 as the main components related to radio communication.
- the wireless communication unit 41 includes an antenna 411, a transmission / reception unit 412, a beacon reception confirmation unit 413, a polling communication unit 414, and a slave unit call communication unit 415.
- the beacon receiving side wireless communication device 40A includes various configurations for functioning as a slave station of the short-range wireless communication network.
- the wireless communication unit 41 performs wireless communication with a “parent wireless terminal” in a broad sense, and is particularly configured to receive a beacon signal.
- the configuration of the wireless communication unit 41 is basically the same as the configuration of the wireless communication unit 31.
- the beacon generation unit 313 included in the wireless communication unit 31 is replaced with the beacon reception confirmation unit 413. It has been replaced.
- the beacon reception confirmation unit 413 confirms whether or not the beacon signal transmitted from the broad “parent wireless terminal” is received via the antenna 411 and the transmission / reception unit 412. More specifically, if the reception of the beacon signal is tried by the antenna 411 and the transmission / reception unit 412 and it is confirmed that the reception of the beacon signal is successful, the received beacon signal is output to the time synchronization unit 45.
- the specific configuration of the beacon reception confirmation unit 413 is not particularly limited, and a known wireless communication circuit that selects and confirms a beacon signal from reception signals output from the transmission / reception unit 412 is used.
- the beacon reception confirmation unit 413 may always try to receive a beacon signal, but in the present embodiment, from the viewpoint of reducing power consumption, timing at which a beacon signal is transmitted from a broad “parent wireless terminal” It is configured to perform a reception attempt according to the above. Therefore, the beacon reception confirmation unit 413 controls the timing of the operation for attempting to receive the beacon signal by the beacon timing control unit 42.
- the relay wireless terminals 111, 121, and 131 shown in FIG. 1 are “parent wireless terminals” in a broad sense and “child wireless terminals” in a broad sense, the relay wireless terminals 111, 121, and 131 are The wireless communication unit 31 (or the wireless communication unit 41) has both a beacon generation unit 313 and a beacon reception confirmation unit 413.
- beacon generation unit 313 and beacon reception confirmation unit 413 may each be a single wireless communication circuit, but may be combined as a single wireless communication circuit.
- the beacon generation unit 313 and the beacon reception confirmation unit 413 are configured as a single functional unit, the functional unit functions as a “beacon communication unit”.
- the time synchronization unit 45 corrects the timing pulse generated by the clock unit 44 based on the beacon signal input from the beacon reception confirmation unit 413.
- the clock unit 44 of the beacon receiving wireless communication device 40A corresponding to the broader “child wireless terminal” is The beacon transmitting side wireless communication device 30A is synchronized with the clock unit 34.
- the time synchronization unit 45 is a functional configuration realized by a CPU (not shown) as a calculation unit included in the beacon reception-side wireless communication device 40A operating according to a program stored in a storage unit (not shown).
- a CPU not shown
- the present invention is not limited to this, and may be configured as a logic circuit using a known switching element, subtractor, comparator, or the like.
- the configuration of the wireless communication unit 41 other than the beacon reception confirmation unit 413 is the same as the configuration of the wireless communication unit 31 described above, and a description thereof will be omitted.
- the configurations of the beacon timing control unit 42, the slot control unit 43, and the clock unit 44 are the same as the configurations of the beacon timing control unit 32, the slot control unit 33, and the clock unit 34 described above, and thus the description thereof is omitted.
- the relay wireless terminals 111, 121, and 131 may include both the beacon generation unit 313 and the beacon reception confirmation unit 413, or may include a “beacon communication unit” in which these are collected.
- the time synchronization unit 45 for correcting the timing pulse of the clock unit 34 or the clock unit 44 is necessarily provided.
- the wireless communication devices 30A and 40A include a beacon communication unit (beacon generation unit 313 or beacon reception confirmation unit 413), a polling communication unit 314 or 414, Since the call communication unit 315 or 415 is included, the wireless communication operation will be specifically described below in the order of beacon communication, polling communication, and handset call communication.
- a beacon communication unit beacon generation unit 313 or beacon reception confirmation unit 413
- a polling communication unit 314 or 414 Since the call communication unit 315 or 415 is included, the wireless communication operation will be specifically described below in the order of beacon communication, polling communication, and handset call communication.
- each of the wireless communication devices 30A and 40A is configured to transmit and receive two types of beacon signals, that is, a first beacon signal and a second beacon signal from the wireless communication unit 31 or 41, respectively, on different channels.
- the transmission and reception of these beacon signals synchronize the clock units 34 and 44 between the wireless communication devices 30A and 40A.
- the first beacon signal and the second beacon signal may be transmitted and received on the same channel.
- the first beacon signal is the main beacon signal, and is transmitted intermittently from the beacon transmission side wireless communication device 30A, for example, on the first channel.
- the beacon receiving side wireless communication device 40A basically, intermittent reception of the first beacon signal is always attempted.
- the second beacon signal is a secondary beacon signal, and is intermittently transmitted from the beacon transmission side wireless communication device 30A, for example, on a second channel different from the first channel.
- the second beacon signal is intermittently attempted to be received in order to cope with the case where the first beacon signal is not successfully received.
- the reception of the second beacon signal may always be attempted, or may be attempted only when the reception of the first beacon signal is not successful.
- the beacon timing control unit 32 periodically transmits the main first beacon signal, so that the wireless communication unit 31 (more specifically, the beacon generation unit 313).
- “First communication operation control” is performed to periodically operate.
- the second beacon signal which is a subordinate, is transmitted at random, or the wireless communication unit 31 (beacon generation unit 313) performs the first communication operation in order to transmit the second beacon signal at random or delayed from the transmission period of the first beacon signal.
- “Second communication operation control” is performed in which the operation is shifted in time from the control operation timing.
- the beacon timing control unit 42 receives the first beacon signal, and in accordance with the periodic transmission of the first beacon signal, the wireless communication unit 41 (more specifically, Specifically, “first communication operation control” for periodically operating the beacon reception confirmation unit 413) is performed. Further, in the reception of the second beacon signal, “second communication operation control” is performed in which the wireless communication unit 41 (beacon reception confirmation unit 413) operates with a time shift from the operation timing of the first communication operation control. Also, the beacon receiving side wireless communication device 40A, in response to the intermittent reception of the first beacon signal and the second beacon signal, provides a predetermined amount to the beacon transmitting side wireless communication device 30A that has transmitted the beacon signal. Terminal call communication can be performed at the timing.
- the basic operation of the wireless communication devices 30A and 40A described above will be described more specifically by giving an example in which a beacon signal is transmitted and received between the parent wireless terminal 101 and the relay wireless terminals 111, 121, and 131 shown in FIG. explain.
- the parent wireless terminal 101 and the relay wireless terminals 111, 121, 131 have a configuration in which, for example, one frame has four time slots.
- time slots two types of slots, an upper slot and a lower slot, are alternately set.
- the upper slot is a slot for communicating with a higher-level wireless communication device
- the lower slot is a slot for communicating with a lower-level wireless communication device. Since the parent wireless terminal 101 is the highest-level wireless communication device, no upper slot is set and the corresponding time slot is unused.
- These time slots are generated by the slot control unit 33 or the slot control unit 43, and the timing is controlled.
- the wireless communication devices that perform communication in the lower slot are the relay wireless terminal 111 and the child wireless terminals 102 to 104 belonging to the same hierarchy (see FIG. 1). Therefore, the upper slot of the relay radio terminal 111 is synchronized with the lower slot of the parent radio terminal 101 and is not shown in FIG. Are also synchronized.
- the relay wireless terminal 111 is a “child wireless terminal” in a broad sense in the first layer and a “parent wireless terminal” in a broad sense in the second layer. Therefore, the wireless communication devices that perform communication in the lower slot of the relay wireless terminal 111 are the relay wireless terminal 121 and the child wireless terminals 112 to 114 (see FIG. 1). Therefore, the upper slot of the relay radio terminal 121 is synchronized with the lower slot of the relay radio terminal 111 and the upper slots of the child radio terminals 112 to 114 (not shown) are synchronized.
- relay radio terminal 121 and the relay radio terminal 131 are similarly synchronized with the lower slot and the upper slot, and thus the description thereof is omitted.
- both the upper slot and the lower slot are composed of a beacon slot, a slave call slot, and a polling slot. These slots are also generated by the slot controller 33 or the slot controller 43, and the timing is controlled.
- the slot length of one upper slot or lower slot is, for example, 2 seconds (2 s), and the slot length of the beacon slot is, for example, 100 milliseconds (100 ms).
- the slot length of the calling slot is, for example, 900 milliseconds (900 ms), and the slot length of the polling slot is, for example, 1,000 milliseconds (1,000 ms).
- the first beacon signal and the second beacon signal are transmitted from the beacon slot of the lower slot and received by the beacon slot of the upper slot.
- the transmission (and reception) of the first beacon signal and the second beacon signal in the beacon slot follows the above-described first communication operation control and second communication operation control. That is, since the first beacon signal is transmitted at the head of the beacon slot, the first beacon signal is periodically transmitted at the timing of the head of the lower slot (first communication operation control). On the other hand, the second beacon signal is transmitted at a random timing, for example, within 100 milliseconds, which is the slot length of the beacon slot.
- the beacon signal is transmitted only once in the lower slot, the first beacon signal and the second beacon signal are alternately transmitted. Therefore, the second beacon signal is transmitted in a state shifted in time from the transmission timing of the first beacon signal (second communication operation control).
- the timing at which the first beacon signal and the second beacon signal are transmitted will be described more specifically.
- the relay radio terminal 111 in the second hierarchy uses the first slot in the upper slot. Receive a beacon signal.
- the time synchronization unit 45 synchronizes its own clock unit 44 with the clock unit 34 included in the parent wireless terminal 101, and the slot control unit 43 corrects the timing of the time slot.
- the relay radio terminal 121 of the third hierarchy receives the first beacon signal in the upper slot, The clock unit 44 is synchronized and the timing is corrected. Further, the relay wireless terminal 121 transmits the first beacon signal to the relay wireless terminal 131 at a lower level (fourth hierarchy).
- the parent radio terminal 101 transmits the second beacon signal in the next lower slot. Since the second beacon signal is transmitted at a random timing within the period of the beacon slot, the relay wireless terminal 111 transmits the second beacon in accordance with the random timing within the period of the beacon slot of the corresponding upper slot. Receive a signal. Such transmission / reception of the second beacon signal is also performed between the relay wireless terminals 111 and 121 or between the relay wireless terminals 121 and 131.
- the parent wireless terminal 101 uses the polling communication unit 314 to start transmitting a polling signal at the head of the polling slot of the lower slot.
- the polling communication unit 414 transmits the polling signal at the head of the polling slot of the upper slot so that the relay wireless terminal 111 and the child wireless terminals 102 to 104 can receive the polling signal transmitted from the parent wireless terminal 101. Try to receive intermittently according to the timing.
- the polling communication unit 414 determines that the polling signal is not transmitted, the polling communication unit 414 immediately stops the reception.
- the relay wireless terminal 111 that has received the polling signal starts transmission of the polling signal at the head of the polling slot of the lower slot.
- the relay wireless terminals 121 and 131 perform polling communication in the same manner.
- the child device call communication unit 415 sets the child device call slot of the lower slot. Transmission of the slave unit call signal is started at the head.
- the master wireless terminal 101 can receive the slave unit call signals from the slave radio terminals 102 to 104 by the slave unit call communication unit 315 at the head of the slave unit call slot of the lower slot. Reception is attempted intermittently in accordance with the timing at which the machine call signal is transmitted.
- the slave unit call communication unit 315 immediately stops reception when it is determined that the slave unit call signal is not transmitted.
- relay radio terminal 111 transmits the slave unit call signal received from slave radio terminals 112 to 114 to master radio terminal 101 at the head of the slave unit call slot of the upper slot by slave unit call communication unit 315.
- slave unit call communication unit 315 the slave unit call signal received from slave radio terminals 112 to 114 to master radio terminal 101 at the head of the slave unit call slot of the upper slot by slave unit call communication unit 315.
- data is transmitted to the master radio terminal 101 via the relay radio terminals 111, 121, and 131. Is sent.
- a beacon signal has a redundant bit signal before the beacon signal.
- the CRC signal is present after the beacon signal.
- the redundant bit signal is a signal formed by repeating “1010...”,
- the CRC signal is a cyclic redundancy check (Cyclic Redundancy Check) signal.
- the beacon signal is composed of a bit synchronization signal, a frame synchronization signal, a control signal, and a higher-order (transmission source) identification code.
- the bit synchronization signal is a signal formed by repeating “1010...”
- the frame synchronization signal is a signal for finding the head of data
- the control signal is a signal for synchronizing the clock unit 44.
- the identification code is hereinafter referred to as ID.
- the bit synchronization signal and the frame synchronization signal are preambles.
- the polling signal and the slave unit call signal are composed of a repetitive header, a bit synchronization signal, a frame synchronization signal, and data.
- the data includes a control signal and a higher-order or lower-order (transmission source or transmission destination) ID.
- the repetitive header has a configuration in which a bit synchronization signal, a frame synchronization signal, and a simple ID are used as a set of constituent elements, and the constituent elements are repeated a plurality of times.
- the simple ID is a shortened version of the standard ID. For example, the standard ID is 48 bits, and the simple ID is 8 bits obtained by taking the lower byte of the standard ID.
- the repetitive header is used for appropriately performing carrier detection between the “parent wireless terminal” and the “child wireless terminal” in a broad sense.
- the reception of the first beacon signal does not receive all the transmitted first beacon signals, but the reception every time a plurality of times. It becomes. Since the reception of the first beacon signal is for the synchronization of the clock unit 44, it is not necessary to perform reception so frequently. For example, when the transmission period of the first beacon signal is 8 seconds and the first beacon signal is received every time the first beacon signal is transmitted 100 times, reception is performed every 800 seconds (this will be described later). ). On the other hand, for example, when receiving a polling signal, it is preferable to shorten the intermittent reception cycle as much as possible in consideration of real-time characteristics. Therefore, the polling signal is received at a cycle of 4 seconds, which is the timing for each upper slot.
- a battery may be used instead of an AC power source.
- the carrier detection operation is performed in the reception with a period of 4 seconds, and the reception is immediately interrupted when there is no carrier.
- the timing at which the carrier detection operation is performed is the polling signal. There may be a deviation from the transmission timing. Such a timing shift leads to a situation in which carrier detection cannot be performed, leading to communication failure.
- the repeated header is used for the purpose of avoiding such a situation.
- the period for receiving the beacon signal to synchronize the clock unit 44 is, for example, 800 seconds as described above, but the length of the repetitive header is set longer than the maximum clock error (described later) in 800 seconds.
- the reception timing is set so that the carrier is detected in the middle of the repeated header.
- the beacon transmitting side wireless communication device 30A for example, the parent wireless terminal 101 alternately transmits the first beacon signal and the second beacon signal every T1 seconds as shown in FIG. This time T1 is referred to as “beacon transmission interval time”.
- the first beacon signal is immediately transmitted at twice the beacon transmission interval time, that is, every 2 ⁇ T1 seconds.
- the second beacon signal is transmitted after a lapse of T3 seconds, which is a random time, based on the timing after the lapse of T1 seconds from the timing at which the immediately preceding first beacon signal is transmitted. That is, since the second beacon signal is transmitted after a delay of T3 seconds from the beacon transmission interval time, this time T3 is referred to as “random delay time”. Since the maximum value (upper limit value) T2 seconds is set as the random delay time, this time T2 is referred to as “maximum delay time”.
- T1 4 seconds
- T2 100 milliseconds
- T3 10 milliseconds ⁇ n (where n is randomly selected from any integer of 0 to 9).
- the transmission time of the first beacon signal and the second beacon signal (the length of the beacon signal) is set to 10 milliseconds or less.
- the beacon receiving side wireless communication device 40A for example, the first layer relay wireless terminal 111 and the child wireless terminals 102 to 104 receive the first beacon signal and the second beacon signal.
- Beacon receiving side wireless communication device 40A is initially not clear at what timing the first beacon signal and the second beacon signal are transmitted. Therefore, the beacon signal receiving operation is performed for a beacon transmission interval time of T1 seconds or more. Continue over.
- letting the wireless communication unit 41 perform a receiving operation to receive a beacon signal is referred to as “a trial of receiving a beacon signal”. If the reception attempt is continued for T1 seconds or longer, the first beacon signal or the second beacon signal is always received.
- a beacon signal may be received from the relay wireless terminal 121 or 131 that is the beacon transmission side wireless communication device 30A other than the first layer.
- the beacon receiving side wireless communication device 40A receives a plurality of beacon signals
- the beacon signal level is equal to or higher than a predetermined level and the beacon signal of the wireless communication device 30A having the smallest number of relay stages is selected.
- the number of relay stages decreases in the order of the relay wireless terminal 131, the relay wireless terminal 121, the relay wireless terminal 111, and the parent wireless terminal 101 (the parent wireless terminal 101 has 0 relay stages). And has the fewest number of relay stages).
- the beacon receiving side wireless communication device 40A cannot receive the first beacon signal, it is required to receive the second beacon signal as much as possible.
- the beacon receiving side wireless communication device 40A sets the time required for receiving the second beacon signal (reception standby time) slightly longer. It is preferable to keep it.
- extending the reception standby time increases power consumption. Therefore, the generation pattern of the random delay time T3 for transmitting the second beacon signal may be shared between the beacon transmission side wireless communication device 30A and the beacon reception side wireless communication device 40A.
- n 10 milliseconds ⁇ n (where n is randomly selected from 0 to 9)
- the value of “n” is shared between the beacon transmission side wireless communication device 30A and the beacon reception side wireless communication device 40A.
- n changes in the order of 3, 7, 1, 5, 8, 2, 0, 9, 4 at each transmission timing of the second beacon signal.
- change data of n is set in advance.
- random delay time T3 30 milliseconds
- random delay time T3 70 milliseconds
- random delay time T3 10 milliseconds (hereinafter omitted).
- the change data of n is also shared by the beacon reception confirmation unit 413 provided in the broader “child wireless terminals” (the child wireless terminals 102 to 104 and the relay wireless terminal 111) belonging to the same hierarchy as the parent wireless terminal 101. . Therefore, in the beacon receiving side wireless communication device 40A, the length of the random delay time T3 of the second beacon signal to be transmitted can be predicted, and therefore the reception standby time can be set as short as possible. As a result, power consumption can be reduced.
- the n change data may be set to be different for each beacon transmission side wireless communication device 30A.
- the second beacon signal may be transmitted after waiting for a time preset in the beacon transmission side wireless communication device 30A. Examples of the preset time include a value related to the terminal number.
- the beacon reception side wireless communication device 40A may try to receive the signal. It is preferable to try reception at a cycle that is an integral multiple of the cycle (2 ⁇ T1) at which the is transmitted. This is because, as described above, the transmission / reception of the beacon signal is intended to synchronize the clock unit 44, and therefore it is not necessary to frequently perform reception attempts.
- the cycle in which the first beacon signal is transmitted is referred to as “beacon transmission cycle”
- the cycle in which the first beacon signal is received is referred to as “beacon reception cycle”
- the beacon reception cycle in the beacon reception side wireless communication device 40A will be specifically described.
- the beacon transmission side wireless communication device 30 ⁇ / b> A has a first beacon signal and a second beacon signal (in the figure, “1” is the first beacon signal).
- N 4 ⁇ (2 ⁇ T1 seconds
- the first beacon signal reception trial timing (beacon reception cycle CR) is synchronized with the first beacon signal transmission timing (beacon transmission cycle CS) (that is, the clock unit). 44), the length of the random delay time T3 needs to be known. That is, if the length of the random delay time T3 is not clear, the base points of the beacon transmission cycle CS and the beacon reception cycle CR based on the beacon transmission interval time T1 cannot be determined. Therefore, the beacon transmission side wireless communication device 30A transmits the second beacon signal after inserting the length data of the random delay time T3 into the signal format of the second beacon signal.
- the beacon receiving side wireless communication device 40A When receiving the second beacon signal, acquires the length data of the random delay time T3 included in the second beacon signal received by the time synchronization unit 45, and outputs the timing pulse of the clock unit 44. Correct for T3 seconds. Thereby, since the clock part 44 synchronizes with the clock part 34 of 30 A of beacon transmission side radio
- beacon signals transmitted and received in each wireless communication system may be in an asynchronous state.
- the beacon transmission cycle CS is transmitted from each parent wireless terminal 101 to all “child wireless terminals”. There is a possibility that beacon signals shifted from each other may be transmitted.
- the beacon transmission interval time T1 is, for example, 4 seconds, and the length of the beacon signal itself (the transmission time of the beacon signal) is, for example, 10 milliseconds, the duty ratio in the transmission of the beacon signal is 1/400. Therefore, even if the beacon signals transmitted from each wireless communication system are asynchronous, the probability of collision becomes low. However, since the beacon transmission interval time T1 set in each wireless communication system includes a slight clock error (described later), the transmission / reception of beacon signals becomes longer, and the clock error in the beacon transmission cycle in each wireless communication system. Therefore, the beacon transmission timing gradually shifts, and as a result, the beacon transmission periods CS may coincide with each other.
- the beacon transmission cycle CS matches, it takes a long time for the beacon transmission cycle to shift again due to clock errors.
- the beacon receiving side wireless communication device 40A included in each wireless communication system cannot receive the first beacon signal.
- the second beacon signal is transmitted after being delayed by a random delay time T3 from the beacon transmission interval time T1 serving as a reference for the beacon transmission cycle CS, so the transmission timing of the second beacon signal is always the first beacon. It will deviate from the signal transmission timing.
- the length of the random delay time T3 is uniquely determined in each wireless communication system, and is randomly determined with the maximum delay time T2 as an upper limit. Therefore, even if the random delay time T3 matches in the two wireless communication systems and the second beacon signal collides once, the possibility that the random delay time T3 matches at the next transmission timing is extremely low. Therefore, the probability that the second beacon signals collide with each other is basically low, and the probability that the second beacon signals collide continuously becomes lower.
- the beacon receiving side wireless communication device 40A can synchronize the clock unit 44 by receiving the second beacon signal.
- the operation of the wireless communication unit 31 is performed so that transmission is performed simultaneously with the elapse of the delay time R (random delay time T3) that is shorter than the waiting time Q. It is the structure to control.
- the slot control unit 43 (and the beacon timing control unit 42) tries to receive the first beacon signal at the cycle P2 (beacon reception cycle CR), and the second beacon signal. Is received at the same time as a delay time R (random delay time T3) that is shorter than the waiting time Q elapses after a waiting time Q (beacon transmission interval time T1) that is shorter than the period P2 elapses. In this way, the operation of the wireless communication unit 41 is controlled.
- the waiting time Q may not be the beacon transmission interval time T1
- the second beacon signal may be transmitted / received randomly or delayed from the transmission / reception timing (period P1 or period P2) of the first beacon signal. Can be transmitted and received, the beacon transmission interval time T1 may be exceeded or less than T1.
- the delay time R may be a random delay time T3 that is equal to or less than the maximum delay time T2, but may be a predetermined length instead of a random length.
- the set times T31, T32, and T33 may be set in advance as the delay time R, and the set times T31 to T33 may be periodically changed when the second beacon signal is transmitted / received. With this configuration, not only can the second beacon signal be transmitted and received delayed from the transmission timing of the transmission and reception of the first beacon signal (cycle P1 or cycle P2), for example, an area where a plurality of wireless communication systems are adjacent or overlapped Even when the second beacon signal is installed, continuous collision of the second beacon signal can be avoided.
- the clock unit synchronization method by transmitting and receiving the beacon signal is the same as the slot control unit 33 (communication control unit) of the beacon transmission side wireless communication device 30A and the slot control unit 43 (communication control unit) of the beacon reception side wireless communication device 40A. 7 and 8 can be illustrated as a control method or a wireless communication method.
- the slot control unit 33 receives the timing pulse of the clock unit 34. Whether or not the transmission timing of the first beacon signal (beacon transmission cycle CS) has been reached is determined (step S101). If the transmission timing has not been reached (NO in step S101), the determination is repeated until the transmission timing is reached. If the transmission timing has been reached (YES in step S101), the beacon timing control unit 32 is activated (step S102), and the beacon timing control unit 32 causes the beacon generation unit 313 to generate the first beacon signal (step S103). ), The first beacon signal is transmitted via the transmission / reception unit 312 and the antenna 311 (step S104).
- the slot control unit 33 determines whether or not the transmission timing of the second beacon signal has been reached (step S105). If the transmission timing has not been reached (NO in step S105), the determination is repeated until the transmission timing is reached. If the transmission timing has been reached (YES in step S105), the beacon timing control unit 32 is activated (step S106), and the beacon timing control unit 32 causes the beacon generation unit 313 to generate the second beacon signal (step S107). ), The second beacon signal is transmitted via the transmitting / receiving unit 312 and the antenna 311 (step S108). Thereafter, the process returns to the determination of the transmission timing of the first beacon signal (step S101). This control is repeated until the beacon transmission side wireless communication device 30A is powered off.
- the slot control unit 43 receives the timing pulse of the clock unit 44. Whether or not the reception timing of the first beacon signal (beacon reception cycle CR) has been reached (step S201). If the reception timing has not been reached (NO in step S201), the determination is repeated until the reception timing is reached. If the reception timing has been reached (YES in step S201), the beacon timing control unit 42 is activated (step S202), and the beacon timing control unit 42 causes the beacon reception confirmation unit 413 to try to receive the first beacon signal. (Step S203).
- the beacon timing control unit 42 causes the beacon reception confirmation unit 413 to determine whether or not the first beacon signal has been successfully received (step S204). If the reception of the first beacon signal is successful (YES in step S204), the beacon timing control unit 42 corrects the timing pulse of the clock unit 44 in the time synchronization unit 45 (step S209). Thereby, the clock part 44 synchronizes with the clock part 34 of 30 A of beacon transmission side radio
- the slot control unit 43 determines whether or not the reception timing of the second beacon signal has been reached from the timing pulse of the clock unit 44. (Step S205). If the reception timing has not been reached (NO in step S205), the determination is repeated until the reception timing is reached. If the reception timing has been reached (YES in step S205), the beacon timing control unit 42 is activated (step S206), and the beacon timing control unit 42 causes the beacon reception confirmation unit 413 to try to receive the second beacon signal. (Step S207).
- the process returns to the determination of the reception timing of the first beacon signal (step S201).
- the beacon timing control unit 42 corrects the timing pulse of the clock unit 44 in the time synchronization unit 45 (step S209).
- the clock part 44 synchronizes with the clock part 34 of 30 A of beacon transmission side radio
- the process returns to the determination of the reception timing of the first beacon signal (step S201). This control is repeated until the power supply of the beacon receiving side wireless communication device 40A is cut off.
- the wireless communication method having the above configuration is performed on a computing device (such as a microcomputer) included in the wireless communication devices 30A and 40A in a wireless communication system including the beacon transmission side wireless communication device 30A and the beacon reception side wireless communication device 40A.
- a computing device such as a microcomputer
- the beacon receiving side wireless communication device 40A when the beacon receiving side wireless communication device 40A does not succeed in receiving the first beacon signal for some reason (for example, an asynchronous wireless communication system exists in the vicinity of the parent wireless terminal 101, and the beacon transmission cycle happens to occur. 2), the second beacon signal can be received, so the clock unit 44 of the beacon receiving side wireless communication device 40A and the clock unit 34 of the beacon transmitting side wireless communication device 30A can be received. And can be synchronized. If the first beacon signal can be properly received, the first beacon signal transmitted at a constant beacon transmission cycle CS (2 ⁇ T1) is intermittently received at the beacon reception cycle CR. Since the clock unit 34 and the clock unit 44 can be synchronized, in particular, the activation time of the beacon receiving side wireless communication device 40A can be shortened to suppress power consumption. That is, according to the present embodiment, it is possible to effectively cope with the interference of the beacon signal and to achieve both reduction of power consumption.
- the beacon receiving side wireless communication device 40A is particularly configured to start the trial taking into account the occurrence of a clock error when attempting to receive the first beacon signal and the second beacon signal. preferable. This point will be specifically described with reference to FIG.
- a clock unit included in a general wireless communication device is configured to oscillate a crystal oscillation signal using a crystal resonator as a reference oscillation source.
- the error (frequency error) generated in the frequency of the crystal oscillation signal is ⁇ 100 ppm at maximum if temperature change is taken into consideration.
- each of the beacon transmission side wireless communication device 30A and the beacon reception side wireless communication device 40A includes a clock unit 34 or a clock unit 44, respectively.
- the frequency error in the clock unit 34 is ⁇ 100 ppm at the maximum and the frequency error in the clock unit 44 is ⁇ 100 ppm at the maximum, the relative frequency error is ⁇ 200 ppm at the maximum.
- the relative frequency error occurring between the clock unit 34 and the clock unit 44 is referred to as “clock error” in this specification.
- beacon receiving side wireless communication device 40A succeeds in receiving the first beacon signal transmitted from the beacon transmitting side wireless communication device 30A and the clock unit 44 can be synchronized, A clock error that cannot be ignored occurs between the clock unit 44 and the clock unit 34 in the time until the first beacon signal is received.
- the length (transmission time) of the beacon signal is 10 milliseconds or less, this clock error affects reception of the beacon signal.
- reception timeout time T6 or T7 is set.
- the reception trial upper limit time T7 is a random delay time T3 elapses after the beacon transmission cycle CS ( It is set to receive the second beacon signal transmitted after waiting.
- the first beacon signal and the second beacon signal have redundant bit signals prior to the beacon signal (see FIG. 6). (See also 5 (a)). Therefore, as shown in “(2) Beacon reception” in FIG. 6C, the reception trial upper limit time T6 or T7 is set to be equal to or longer than the length of the beacon signal including the redundant bit signal. . As shown in “(2) Beacon reception” in FIG. 6C, the beacon signal reception operation takes a little longer than the beacon signal length.
- the starting point PS of the transmission timing of the beacon signal and the starting point PR of the reception timing should normally coincide, but if a clock error occurs, it will deviate greatly.
- the algebra of the maximum clock error is set to X (seconds)
- the transmission timing start point PR is greater than the reception timing start point PS. To shift X seconds ago.
- the schematic diagram shown in FIG. 6C emphasizes the redundant bit signal and the beacon signal and does not reflect the actual length of time.
- the beacon transmission interval time T1 4 seconds
- the beacon signal length (transmission time) is set to 10 milliseconds or less, but the maximum clock error X is 6.4 milliseconds. obtain. Therefore, the upper limit of the length of the reception trial upper limit time T6 or T7 is set to 2 of the maximum clock error X in consideration of the fact that the maximum clock error X occurs not after the starting point PS ( ⁇ X) but after (+ X). Just double it.
- the reception trial upper limit time T6 is (X + T4 + T8) ⁇ T6 ⁇ 2 ⁇ X.
- the reception trial upper limit time T7 is (X + T2 + T4 + T8) ⁇ T7 ⁇ (2 ⁇ X + T2) because the maximum delay time T2 needs to be considered in addition to the maximum clock error X.
- the detection of the redundant bit signal is first attempted before the start of the beacon signal reception attempt.
- the length of the redundant bit signal is T4.
- the configuration of the redundant bit signal is “1010...” As described above. Therefore, if the redundant bit detection trial time T5 for trying to detect a redundant bit signal is set to a length such that the above repetition can be confirmed within a range not exceeding the length T4 of the redundant bit signal. Good (T5 ⁇ T4).
- beacon receiving side wireless communication device 40A attempts to detect the redundant bit signal at the reception trial upper limit time T6 or T7 will be specifically described together with the reception of the first beacon signal and the second beacon signal.
- reception trial upper limit times T6 and T7 are set in advance in consideration of maximum clock error ⁇ X, and redundant bit detection trial time T5 is set in advance. Has been. Therefore, in order to absorb the maximum clock error X, the beacon timing control unit 42 sends a redundant bit to the beacon reception confirmation unit 413 earlier than the transmission timing (starting point PS) of the first beacon signal by X seconds (starting point PR). The signal detection operation is started. This detection operation is performed by repeating detection attempts a plurality of times at intervals of the redundant bit detection trial time T5 during the reception trial upper limit time T6 seconds.
- wireless communication apparatus 40A should just cancel reception trial upper limit time T6 and will continue reception of a 1st beacon signal, if a redundant bit signal is detected.
- the redundant bit signal of the second beacon signal is also T4 long.
- the beacon reception confirmation unit 413 starts the redundant bit signal detection operation X seconds earlier than the transmission timing of the first beacon signal.
- the detection operation is performed by repeating detection attempts a plurality of times at intervals of the redundant bit detection trial time T5 during the reception trial upper limit time T7 seconds. Is called.
- the beacon receiving side wireless communication device 40A can surely detect the redundant bit within the reception trial upper limit time T7, and thus can appropriately receive the second beacon signal.
- wireless communication apparatus 40A should just cancel reception trial upper limit time T7, and may continue reception of a 2nd beacon signal, if a redundant bit signal is detected.
- the reception trial upper limit time T6 is set to at most twice the length of the first beacon signal of 10 milliseconds. Good. The reason is that, in the example of the present embodiment, the first beacon signal is about 10 milliseconds, and the maximum clock error X is generally longer than the length of the first beacon signal of 10 milliseconds even when the current consumption is taken into consideration. By being calculated small.
- the reception trial upper limit time T7 may be set to a value slightly larger than 110 milliseconds.
- the maximum delay time T2 is 90 milliseconds at the maximum, and the maximum lock error X is about 10 milliseconds as described above. Therefore, even if the reception trial upper limit times T6 and T7 are set when a beacon signal is received, the influence on the power consumption of the beacon reception-side wireless communication device 40A is insignificant.
- the transmission time of the redundant bit signal and the beacon signal in “(1) Beacon transmission” and the reception time of the beacon signal in “(2) Beacon reception” shown in FIG. An ideal state in which no clock error occurs between the clock unit 34 of 30A and the clock unit 44 of the beacon receiving side wireless communication device 40A is shown. When a clock error actually occurs, the transmission period of the redundant bit signal and the beacon signal is shifted back and forth within the range of the maximum clock error ⁇ X with respect to the reception time of the beacon signal.
- the beacon receiving side wireless communication device 40A attempts to detect the redundant bit signal of the first beacon signal for each redundant bit detection trial time T5 during the reception trial upper limit time T6 slightly longer than the maximum clock error ⁇ X. Can be repeated.
- the first beacon signal can be detected appropriately. Therefore, in order to receive the first beacon signal, the activation time of the beacon reception confirmation unit 413 and the beacon timing control unit 42 can be further shortened, and thus the power consumption of the beacon reception side wireless communication device 40A is suppressed. be able to.
- the second beacon signal is detected every redundant bit detection trial time T5 for a reception trial upper limit time T7 slightly longer than the time obtained by adding the maximum delay time T2 to the maximum clock error ⁇ X. What is necessary is just to repeat a detection trial about the redundant bit signal of a beacon signal. Thereby, the second beacon signal can also be detected appropriately.
- the number of attempts to receive the second beacon signal is much smaller than the number of attempts to receive the first beacon signal.
- the circuit scale may increase. It is avoided and therefore an increase in cost can be avoided. Furthermore, even if the communication ranges of the “parent wireless terminals” in a broad sense overlap and the beacon signals transmitted from the respective “parent wireless terminals” collide with each other, interference occurs and the wireless communication system does not go down. Departments can be synchronized.
- the first beacon signal and the second beacon signal are alternately transmitted, but the present invention is not limited to this, for example, the first beacon signal is transmitted only once, and The second beacon signal may be transmitted a plurality of times (for example, four times), the first beacon signal may be transmitted a plurality of times (for example, four times), and the second beacon signal may be transmitted only once. There may be. Furthermore, you may comprise so that only a 2nd beacon signal may be transmitted according to a condition. The transmission ratio of the first beacon signal and the second beacon signal may be determined based on a balance between power consumption and resistance when the beacon signal is disturbed.
- the first beacon signal is transmitted in a preset cycle P1 (beacon transmission cycle CS), and in the beacon reception side wireless communication device 40A.
- the first beacon signal is tried to be received at a preset cycle P2 (beacon reception cycle CR). That is, in the present embodiment, the transmission / reception timing of the beacon signal is a periodic pattern (periodic pattern), but the present invention is not limited to this, and transmission / reception can be performed with various timing patterns.
- the transmission / reception timing pattern P1 or P2 of the first beacon signal may be (1) a periodic pattern in which the timing of each transmission / reception is a constant cycle, (2 ) A random pattern (non-periodic pattern) in which the timing of each transmission / reception is not a fixed cycle may be used.
- this random pattern a complete random pattern in which the timing of each transmission / reception is a different interval, a quasi-random pattern in which the timing of each transmission / reception is different (that is, a pattern having a constant period at a plurality of transmission / reception timings). ), Or a combination of these.
- it may be a pattern other than (1) or (2). That is, in the present invention, it is only necessary to share the timing pattern between the beacon transmitting side wireless communication device and the beacon receiving side wireless communication device.
- the short-range wireless communication network is illustrated as an example of the wireless communication system, but the present invention is not limited to this, and mobile communication, local wireless communication network, radio for transportation, disaster prevention administration
- the present invention can also be applied to a wireless meter reading system for meters such as a wireless network, gas, water, and electric power.
- the wireless meter reading system will be specifically described in the second embodiment.
- the present invention includes a wireless communication device having the configuration described below. That is, the wireless communication apparatus according to the present invention includes a beacon generation unit and a slot control unit that activates the beacon generation unit and controls timing for periodically transmitting a beacon, and the slot control unit is determined in advance. In the beacon transmission timing II for each given beacon transmission count, the beacon generation means is activated to transmit the second beacon signal at a random or predetermined time delay, and the slot control means other than the beacon transmission timing II In the beacon transmission timing I, the wireless communication apparatus is configured to immediately activate the beacon generation unit and transmit the first beacon signal.
- another wireless communication apparatus includes a beacon generation unit, and a slot control unit that activates the beacon generation unit and controls a timing for periodically transmitting a beacon.
- the beacon generation unit is activated to transmit the second beacon signal at random or after a predetermined time delay
- the slot control unit transmits the beacon transmission timing II.
- Wireless communication for receiving the first beacon signal or the second beacon signal transmitted from a wireless communication device configured to immediately activate the beacon generation unit and transmit the first beacon signal at beacon transmission timing I other than A beacon receiving means and activating the beacon receiving means
- Slot control means for controlling the timing of periodically receiving the remote control, and the slot control means activates the beacon receiving means to receive the first beacon signal and receives the first beacon signal. Is a wireless communication apparatus configured to determine whether to activate the beacon receiving means at a timing at which the second beacon signal is transmitted.
- the beacon transmission timing I and the beacon transmission timing II are slot control means configured to be alternately activated, and alternately output the first beacon signal and the second beacon signal. It may be a configuration.
- the wireless communication device may be a slot control means that operates at the timing of only the beacon transmission timing II.
- the slot control unit can activate the beacon receiving unit at a cycle that is an integral multiple of the timing at which the first beacon signal is transmitted, and the beacon receiving unit can receive the first beacon signal.
- the configuration may be such that the beacon receiving means is activated at the timing when the next second beacon signal is transmitted only when there is not.
- the slot control unit may change a reception timeout time of the beacon receiving unit when receiving the first beacon signal and when receiving the second beacon signal.
- the wireless communication device is a program for causing a computer to realize at least a part of the wireless communication device having the above-described configuration
- at least one of the present invention is performed by cooperating hardware resources such as electrical / information equipment and a computer. Can be realized with simple hardware. Further, by recording on a recording medium or distributing a program using a communication line, it is possible to easily distribute or update the program or install the program.
- the wireless communication method includes a beacon generation unit and a slot control unit that activates the beacon generation unit and controls a timing for periodically transmitting a beacon, and the slot control unit is predetermined.
- the beacon generation means is activated to transmit the second beacon signal at a random or predetermined time delay, and the slot control means transmits beacon transmissions other than the beacon transmission timing II.
- the wireless communication method immediately activates the beacon generation means and transmits the first beacon signal.
- the wireless communication device By using the wireless communication device, the wireless communication method, and the program of the present invention, it is possible to prevent the beacon signals from interfering with each other and to prevent the communication system from going down even when a plurality of communication systems exist in the vicinity.
- the wireless communication system is a wireless communication system including a plurality of wireless communication devices that transmit and receive beacon signals to each other, and two types of first beacon signals and second beacon signals are used as the beacon signals.
- the first beacon signal is transmitted periodically, and the second beacon signal is transmitted while being shifted in time from the transmission timing of the first beacon signal;
- a beacon that periodically tries to receive a beacon signal in accordance with the transmission period of the first beacon signal and tries to receive the second beacon signal in accordance with the transmission timing of the second beacon signal. It can be said that it is the structure containing a receiving side radio
- a wireless communication device is used in a wireless communication system including a plurality of wireless communication devices that transmit and receive beacon signals to each other, and is configured to perform at least one of transmission and reception of the beacon signal
- a wireless communication apparatus comprising: a wireless communication unit that performs wireless communication; and a communication control unit that controls operation timing of the wireless communication unit in order to intermittently transmit and receive the beacon signal, wherein the wireless communication unit
- the beacon signal is configured to transmit and receive the first beacon signal and the second beacon signal, and the communication control unit periodically transmits the first beacon signal to transmit and receive the first beacon signal.
- the first communication operation control to be operated and the second beacon signal are transmitted while being shifted in time from the transmission / reception timing of the first beacon signal.
- the wireless communication unit is configured to perform both the second communication operation control that causes the wireless communication unit to operate with a time shift from the operation timing of the first communication operation control. it can.
- Embodiment 2 The radio communication system and radio communication apparatus according to Embodiment 2 of the present invention are applied to a gas meter radio meter reading system.
- the radio communication system and radio communication apparatus according to the present embodiment will be specifically described with reference to FIGS.
- the wireless communication system includes a wireless master device 201, relay wireless terminals 211, 221, 231 and wireless slave devices 202 to 204, 212 to 214, 222 to 224.
- the wireless master device 201 corresponds to the parent wireless terminal 101 in the first embodiment
- the relay wireless terminals 211, 221, and 231 correspond to the relay wireless terminals 111, 121, and 131 in the first embodiment
- the wireless slave devices 202 to 204 , 212 to 214 and 222 to 224 correspond to the child radio terminals 102 to 104, 112 to 114, and 122 to 124 in the first embodiment.
- gas meters 502 to 504, 512 to 514, and 522 to 524 are connected to the wireless slave devices 202 to 204, 212 to 214, and 222 to 224, respectively.
- the gas meters 502 to 504, 512 to 514, and 522 to 524 connected to the wireless slave devices 202 to 204, 212 to 214, and 222 to 224 are polled from the wireless master device 201.
- Gas meter reading data is collected in the wireless master device 201.
- the collected gas meter reading data is transmitted to the data center using a public line connected to the wireless master device 201, for example.
- the relay wireless terminals 211, 211, and 231 may have only a function of relaying gas meter reading data, but may also have a function of “wireless slave”. In this case, a gas meter is also connected to these relay wireless terminals 211, 221, and 231.
- the wireless master device 201 and the relay wireless terminals 211, 211, and 231 correspond to the beacon transmission side wireless communication device 30B shown in FIG. 10, and the wireless slave devices 202 to 204, 212 to 214, 222 to 224, and the relay wireless terminals. 211, 221, and 231 correspond to the beacon receiving side wireless communication device 40B shown in FIG.
- beacon transmission side wireless communication device 30B is basically the same as that of beacon transmission side wireless communication device 30A in the first embodiment, but is acquired from gas meters 502-504, 512-514, 522-524.
- a flow rate collecting unit 35 for receiving and collecting gas meter reading data (that is, gas flow rate data) transmitted from the beacon receiving side wireless communication device 40B by the transmitting / receiving unit 312 is provided.
- the configuration of the beacon receiving side wireless communication device 40B is basically the same as that of the beacon transmitting side wireless communication device 30A in the first embodiment, but each gas meter 502 to 504, 512 to 514, 522 to
- a flow rate acquisition unit 46 that acquires gas meter reading data (gas flow rate data) from 524 and outputs the data to the transmission / reception unit 412 is provided.
- the polling communication performed by the polling communication units 314 and 414 uses the gas meter reading data from the gas meters 502 to 504, 512 to 514 and 522 to 524. This is communication for transmitting a polling signal from the wireless master device 201 for collection in the wireless master device 201. Further, the slave unit call communication performed by the slave unit call communication units 315 and 415 is performed by the gas meters 502 to 504, 512 to 514, and 522 to the wireless slave units 202 to 204, 212 to 214, and 222 to 224.
- Gas meter is configured to operate on battery power without replacement for 10 years, and there is almost no configuration with AC power. Therefore, the wireless communication device attached to the gas meter needs to operate without battery replacement for 10 years by battery driving. Therefore, the wireless communication device intermittently performs a reception operation at a predetermined cycle, and if it cannot detect a radio wave addressed to itself, it immediately stops reception (reception trial) and enters a standby state. It is carried out. Further, the meter reading of the gas meter does not need to be frequently measured, and is at most once a day, and therefore the frequency of wireless communication is not great.
- the asynchronous method is a method for transmitting the transmission information by attaching a header signal longer than the intermittent reception cycle of the communication partner only when information to be transmitted (transmission information) is generated.
- the communication partner can detect a header signal longer than the intermittent reception cycle, and when the header signal is detected, the transmission partner can continue receiving and receive the transmission information transmitted following the header signal.
- a specific intermittent reception cycle a longer time of 20 seconds is usually set in order to suppress battery consumption.
- a single-to-multiple wireless communication system that attempts to collect meter reading values of a large number of gas meters with a single wireless master unit has been studied. Furthermore, in order to increase the number of gas meters that can collect data in the wireless master unit, a one-to-multiple wireless communication system having a relay function is also being studied. In such a one-to-multiple wireless communication system, the number of communications in the entire wireless communication system increases. As a result, in the conventional asynchronous method, it is necessary to transmit a header signal having a length of 20 seconds or more as an intermittent reception cycle per one communication.
- the traffic of the entire wireless communication system deteriorates, and the number of times of receiving a header signal not addressed to the own station increases, resulting in an increase in current consumption.
- the clock unit provided in each of the wireless master unit and the wireless slave unit is used as a reference, and the synchronization signal cannot be received regularly and it takes time, the transmission / reception timing error increases, and the intermittent reception timing increases. The reception time tends to increase and power consumption increases.
- the gas meter wireless meter reading system avoids an increase in circuit scale as described in the first embodiment, and therefore can avoid an increase in cost. ing. Further, even if the first beacon signals collide with each other and interference occurs, the clock unit can be synchronized without the wireless communication system going down by transmitting and receiving the second beacon signal, and the first beacon signal Since the transmission / reception of the second beacon signal is performed very efficiently, an increase in power consumption can be effectively suppressed.
- a configuration for automatically collecting gas flow rate data (gas meter reading data) from a gas meter is illustrated, but the present invention is not limited to this, and a system for metering the flow rate of water, electricity, etc. Needless to say, it may be.
- the present invention is a wireless communication system such as a short-range wireless communication network, mobile communication, a private wireless communication network, a radio for transportation, a disaster prevention administrative wireless network, a wireless LAN, a meter reading system for gas, water, and power.
- the present invention can be suitably used in the field of communication systems and wireless communication devices used in these systems.
Abstract
Description
本発明の実施の形態1に係る無線通信システムは、本発明に係る無線通信装置として、親無線端末、中継無線端末、および子無線端末を含む近距離無線通信ネットワークとなっている。以下、本実施の形態に係る無線通信システムおよび無線通信装置について、図面を参照して具体的に説明する。
図1に示すように、本実施の形態に係る無線通信システムは、無線通信装置として、親無線端末101、中継無線端末111,121,131および子無線端末102~104,112~114,122~124を含んでいる。なお、図1では、説明の便宜上、親無線端末を1台、中継無線端末を3台、子無線端末を9台図示しているが、無線通信システムの構成はこれに限定されるものではなく、これら無線通信装置は、図示されている台数を超えて含まれてもよいし、図示されている台数未満であってもよい。
次に、前述した各無線通信装置は、本実施の形態に係る無線通信装置であるが、これらについて、ビーコン信号の送受信に関係する構成を中心に、図2および図3を参照して具体的に説明する。
次に、本実施の形態に係る無線通信システムと、これを構成する無線通信装置30Aおよび40Aの動作について、図4(a),(b)および図5(a)~(c)を参照して具体的に説明する。
次に、第1ビーコン信号および第2ビーコン信号の送受信によるクロック部44の同期について、図6(a),(b)、図7および図8を参照して具体的に説明する。
ここで、ビーコン受信側無線通信装置40Aにおいては、第1ビーコン信号および第2ビーコン信号の受信の試行に際して、クロック誤差の発生を考慮に入れて試行を開始するように構成されていることが特に好ましい。この点について、図6(c)を参照して具体的に説明する。
本実施の形態では、第1ビーコン信号および第2ビーコン信号は交互に送信されているが、本発明はこれに限定されるものではなく、例えば、第1ビーコン信号を1回のみ送信し、かつ、第2ビーコン信号を複数回(例えば4回)送信する構成としてもよいし、第1ビーコン信号を複数回(例えば4回)送信し、かつ、第2ビーコン信号を1回のみ送信する構成であってもよい。さらに、状況に応じて第2ビーコン信号のみを送信するように構成してもよい。なお、第1ビーコン信号および第2ビーコン信号の送信比率は、電力消費とビーコン信号が妨害を受けたときの耐性との兼ね合いから決定されればよい。
本発明の実施の形態2に係る無線通信システムおよび無線通信装置は、ガスメータ用無線検針システムに適用されたものである。本実施の形態に係る無線通信システムおよび無線通信装置について、図9ないし図11を参照して具体的に説明する。
31 無線通信部
32 ビーコンタイミング制御部(通信制御部)
33 スロット制御部(通信制御部)
34 クロック部
40A ビーコン受信側無線通信装置(子無線端末)
41 無線通信部
42 ビーコンタイミング制御部(通信制御部)
43 スロット制御部(通信制御部)
44 クロック部
45 時間同期部
101 親無線端末(無線通信装置)
102~104 子無線端末(無線通信装置)
111 中継無線端末(無線通信装置)
112~114 子無線端末(無線通信装置)
121 中継無線端末(無線通信装置)
122~124 子無線端末(無線通信装置)
131 中継無線端末(無線通信装置)
Claims (14)
- 互いにビーコン信号を通信する複数の無線通信装置を含む無線通信システムに用いられ、かつ、前記ビーコン信号の送信および受信の少なくとも一方を行うように構成され、
無線通信を行う無線通信部と、
前記ビーコン信号を間欠的に通信するために、前記無線通信部の動作タイミングを制御する通信制御部と、を備える無線通信装置であって、
前記ビーコン信号として、第1ビーコン信号および第2ビーコン信号の送信を行うように構成され、
前記通信制御部は、前記第1ビーコン信号を、予め設定されているタイミングパターンP1で送信させるとともに、
前記第2ビーコン信号を、前記タイミングパターンP1より短い時間である待機時間Qが経過した後に、当該待機時間Qよりも短い時間である遅延時間Rが経過すると同時に送信させるように、前記無線通信部の動作を制御することを特徴とする、無線通信装置。 - 時間間隔を規定するタイミングパルスを周期的に発生するクロック部をさらに備え、
前記第1ビーコン信号および前記第2ビーコン信号は、前記他の無線通信装置との間で、前記クロック部の動作を互いに同期させる制御に用いられることを特徴とする、請求項1に記載の無線通信装置。 - 前記第1ビーコン信号および前記第2ビーコン信号の受信を行うように構成され、
前記通信制御部は、前記第1ビーコン信号の受信を、予め設定されているタイミングパターンP2で試行させるとともに、
前記第2ビーコン信号の受信を、前記タイミングパターンP2より短い時間である待機時間Qが経過した後に、当該待機時間Qよりも短い時間である遅延時間Rの経過に合わせて試行させるように、前記無線通信部の動作を制御することを特徴とする、請求項1に記載の無線通信装置。 - 前記通信制御部は、前記タイミングパターンP1またはP2を、送受信の毎回のタイミングが一定の周期である周期パターン、または、送受信の毎回のタイミングが一定の周期ではないランダムパターンとして設定していることを特徴とする、請求項3に記載の無線通信装置。
- 前記待機時間Qは、予め所定の長さとして設定される設定値であり、
前記遅延時間Rは、長さが変化可能なランダム値であることを特徴とする、請求項4に記載の無線通信装置。 - 前記第2ビーコン信号は、前記遅延時間Rの長さを示す情報を含むことを特徴とする、請求項5に記載の無線通信装置。
- 前記タイミングパターンP1およびP2が周期パターンであるときに、
前記通信制御部は、前記他の無線通信装置から前記第1ビーコン信号が送信される周期の整数倍の周期で、当該第1ビーコン信号の受信を試行させるとともに、当該第1ビーコン信号の受信が成功しない場合のみ、前記第2ビーコン信号を受信させるように、前記無線通信部の動作を制御することを特徴とする、請求項4に記載の無線通信装置。 - 前記通信制御部は、前記無線通信部による前記第1ビーコン信号および前記第2ビーコン信号の受信の試行を、予め設定された受信試行上限時間内で行わせるように、前記無線通信部の動作を制御するとともに、
前記受信試行上限時間は、前記第1ビーコン信号の受信を試行する場合と前記第2ビーコン信号の受信を試行する場合とで、それぞれ異なっていることを特徴とする、請求項7に記載の無線通信装置。 - 請求項1から8のいずれか1項に記載の無線通信装置を通信端末として含むことを特徴とする、無線通信システム。
- 前記無線通信装置のうち、前記第1ビーコン信号および前記第2ビーコン信号を送信する前記無線通信装置が、データ収集を行う親無線端末であり、
前記第1ビーコン信号および前記第2ビーコン信号を受信する前記無線通信装置が、前記親無線端末へ送信するためのデータを取得する子無線端末であることを特徴とする、請求項9に記載の無線通信システム。 - 複数の前記無線通信装置のうち、前記親無線端末から送信される前記第1ビーコン信号および前記第2ビーコン信号を受信するとともに、前記子無線端末へ前記第1ビーコン信号および前記第2ビーコン信号を送信する前記無線通信装置が、前記親無線端末および前記子無線端末の間の通信を中継する中継無線端末であることを特徴とする、請求項10に記載の無線通信システム。
- 前記子無線端末は、流体の流量を計測する流量計から前記流量データを取得する流量取得部をさらに備え、
前記親無線端末は、前記子無線端末から前記流量データを受信して収集する流量収集部をさらに備えていることを特徴とする、請求項10に記載の無線通信システム。 - ビーコン信号を間欠的に送信する無線通信装置を親無線端末として備え、前記ビーコン信号を間欠的に受信する無線通信装置を子無線端末として備えている、無線通信システムに用いられる無線通信方法であって、
前記親無線端末から、第1ビーコン信号を、予め設定されているタイミングパターンP1で送信するステップと、
前記子無線端末において、前記第1ビーコン信号の受信を、予め設定されているタイミングパターンP2で試行するステップと、
前記親無線端末から、前記第2ビーコン信号を、前記タイミングパターンP1より短い時間である待機時間Qが経過した後に、当該待機時間Qよりも短い時間である遅延時間Rが経過すると同時に送信するステップと、
前記子無線端末において、前記第2ビーコン信号の受信を、前記タイミングパターンP2より短い時間である待機時間Qが経過した後に、当該待機時間Qよりも短い時間である遅延時間Rの経過に合わせて試行するステップと、を含むことを特徴とする、無線通信方法。 - ビーコン信号を送信する無線通信装置を親無線端末として備え、前記ビーコン信号を受信する無線通信装置を子無線端末として備えている、無線通信システムにおいて、前記ビーコン信号の送受信処理を前記無線通信装置が備えるコンピュータ上で実行するように、コンピュータ読取可能な形式で記述されたプログラムであって、
前記ビーコン信号として、第1ビーコン信号および第2ビーコン信号が間欠的に送受信されるように、前記無線通信装置が構成され、
前記無線通信装置が前記親無線端末である場合には、前記第1ビーコン信号を、予め設定されているタイミングパターンP1で送信するステップと、前記第2ビーコン信号を、前記タイミングパターンP1より短い時間である待機時間Qが経過した後に、当該待機時間Qよりも短い時間である遅延時間Rが経過すると同時に送信するステップと、を前記コンピュータに実行させ、
前記無線通信装置が前記子無線端末である場合には、前記第1ビーコン信号の受信を、予め設定されているタイミングパターンP2で試行するステップと、前記第2ビーコン信号の受信を、前記タイミングパターンP2より短い時間である待機時間Qが経過した後に、当該待機時間Qよりも短い時間である遅延時間Rの経過に合わせて試行するステップと、を前記コンピュータに実行させることを特徴とする、プログラム。
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP10799631A EP2413646A4 (en) | 2009-07-15 | 2010-07-14 | Radio communication device, radio communication system, radio communication method and program for carrying out the radio communication method |
CN201080031769.XA CN102474837B (zh) | 2009-07-15 | 2010-07-14 | 无线通信装置、无线通信系统以及无线通信方法 |
US13/320,456 US20120057620A1 (en) | 2009-07-15 | 2010-07-14 | Radio communication device, radio communication system, radio communication method, and program for executing radio communication method |
JP2011522735A JP5491507B2 (ja) | 2009-07-15 | 2010-07-14 | 無線通信装置、無線通信システム、および無線通信方法、並びにこの無線通信方法を実行させるプログラム |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2009-166558 | 2009-07-15 | ||
JP2009166558 | 2009-07-15 | ||
JP2009183003 | 2009-08-06 | ||
JP2009-183003 | 2009-08-06 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2011007567A1 true WO2011007567A1 (ja) | 2011-01-20 |
Family
ID=43449177
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2010/004582 WO2011007567A1 (ja) | 2009-07-15 | 2010-07-14 | 無線通信装置、無線通信システム、および無線通信方法、並びにこの無線通信方法を実行させるプログラム |
Country Status (5)
Country | Link |
---|---|
US (1) | US20120057620A1 (ja) |
EP (1) | EP2413646A4 (ja) |
JP (1) | JP5491507B2 (ja) |
CN (1) | CN102474837B (ja) |
WO (1) | WO2011007567A1 (ja) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2012175226A (ja) * | 2011-02-18 | 2012-09-10 | Sharp Corp | 多段中継ネットワーク、多段中継から成る無線テレメータシステム及び無線テレメータシステムに用いられる無線子機 |
CN103036813A (zh) * | 2011-09-30 | 2013-04-10 | 冲电气工业株式会社 | 中继单元 |
JP2015503887A (ja) * | 2012-01-12 | 2015-02-02 | クアルコム,インコーポレイテッド | ワイヤレスネットワークを外部タイミングソースと同期させるための方法および装置 |
JP2015023304A (ja) * | 2013-07-16 | 2015-02-02 | 富士電機株式会社 | 無線通信ネットワークシステム、常時動作無線端末、無線通信方法、および、プログラム |
JPWO2014013667A1 (ja) * | 2012-07-19 | 2016-06-30 | パナソニックIpマネジメント株式会社 | 検針装置 |
WO2018180762A1 (ja) * | 2017-03-29 | 2018-10-04 | パナソニックIpマネジメント株式会社 | 無線通信装置、無線通信用プログラム、および中継器 |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5216511B2 (ja) * | 2008-09-30 | 2013-06-19 | アズビル株式会社 | 流量計測システム |
WO2013125190A1 (ja) * | 2012-02-20 | 2013-08-29 | パナソニック株式会社 | 多層式の無線通信システム |
US8867421B2 (en) * | 2012-04-12 | 2014-10-21 | Gainspan Corporation | Correction of clock errors in a wireless station to enable reduction of power consumption |
US20130272455A1 (en) * | 2012-04-13 | 2013-10-17 | Qualcomm Incorporated | Systems and methods for clock compensation |
KR102072595B1 (ko) * | 2012-06-13 | 2020-03-02 | 한국전자통신연구원 | 무선랜에서 채널 액세스 관련정보를 요청 및 획득하는 방법 및 단말, 무선랜에서 채널 액세스 관련정보를 제공하는 장치 |
WO2013187702A1 (ko) * | 2012-06-13 | 2013-12-19 | 한국전자통신연구원 | 무선랜에서 채널 액세스 관련정보를 요청 및 획득하는 방법 및 단말, 무선랜에서 채널 액세스 관련정보를 제공하는 장치 |
US9191908B2 (en) * | 2013-03-05 | 2015-11-17 | Qualcomm Incorporated | Reducing impact of clock drift in wireless devices |
WO2015073543A1 (en) * | 2013-11-12 | 2015-05-21 | Marvell World Trade Ltd. | Method and apparatus for synchronizing timing among devices in a wireless local area network (wlan) |
US10314107B2 (en) * | 2015-04-21 | 2019-06-04 | Mitsubishi Electric Corporation | Communication device, communication method, and communication system |
US9572093B2 (en) | 2015-04-30 | 2017-02-14 | Sk Planet Co., Ltd. | Method, apparatus, and system for providing plurality of services using one beacon |
JP6678326B2 (ja) * | 2016-07-19 | 2020-04-08 | パナソニックIpマネジメント株式会社 | 通信装置及び通信システム |
JP6709982B2 (ja) * | 2016-07-19 | 2020-06-17 | パナソニックIpマネジメント株式会社 | 通信システム、通信装置 |
US10712561B2 (en) * | 2016-11-04 | 2020-07-14 | Microsoft Technology Licensing, Llc | Interference mitigation via adaptive depth imaging |
JP6832794B2 (ja) * | 2017-06-05 | 2021-02-24 | ルネサスエレクトロニクス株式会社 | 無線通信システム |
JP2020088624A (ja) * | 2018-11-27 | 2020-06-04 | セイコーエプソン株式会社 | 電子機器 |
US11700146B2 (en) * | 2020-08-26 | 2023-07-11 | Microchip Technology Incorporated | EMI reduction in PLCA-based networks through beacon temporal spreading |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07284170A (ja) | 1995-04-28 | 1995-10-27 | Matsushita Electric Ind Co Ltd | 自動検針システム |
JP2005072677A (ja) | 2003-08-27 | 2005-03-17 | Sharp Corp | 無線通信システム、無線通信システムにおける無線装置および移動無線装置 |
JP2007174709A (ja) * | 2007-03-19 | 2007-07-05 | Matsushita Electric Works Ltd | 伝送システム |
JP2007221392A (ja) * | 2006-02-15 | 2007-08-30 | Mitsumi Electric Co Ltd | チャンネルサーチ方法、及び、それを用いた通信装置 |
JP2008085650A (ja) * | 2006-09-27 | 2008-04-10 | Funai Electric Co Ltd | クライアント・サーバシステム |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101662816B (zh) * | 2003-02-03 | 2014-03-05 | 索尼株式会社 | 无线通信系统,无线通信设备和无线通信方法及计算机程序 |
JP4396416B2 (ja) * | 2003-10-24 | 2010-01-13 | ソニー株式会社 | 無線通信システム、無線通信装置及び無線通信方法、並びにコンピュータ・プログラム |
CN1856963B (zh) * | 2003-10-24 | 2011-06-08 | 索尼株式会社 | 无线通信系统、无线通信设备和无线通信方法 |
US7706822B2 (en) * | 2005-08-24 | 2010-04-27 | Motorola, Inc. | Timing synchronization and beacon generation for mesh points operating in a wireless mesh network |
US8059009B2 (en) * | 2006-09-15 | 2011-11-15 | Itron, Inc. | Uplink routing without routing table |
-
2010
- 2010-07-14 JP JP2011522735A patent/JP5491507B2/ja not_active Expired - Fee Related
- 2010-07-14 EP EP10799631A patent/EP2413646A4/en not_active Withdrawn
- 2010-07-14 US US13/320,456 patent/US20120057620A1/en not_active Abandoned
- 2010-07-14 WO PCT/JP2010/004582 patent/WO2011007567A1/ja active Application Filing
- 2010-07-14 CN CN201080031769.XA patent/CN102474837B/zh not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07284170A (ja) | 1995-04-28 | 1995-10-27 | Matsushita Electric Ind Co Ltd | 自動検針システム |
JP2005072677A (ja) | 2003-08-27 | 2005-03-17 | Sharp Corp | 無線通信システム、無線通信システムにおける無線装置および移動無線装置 |
JP2007221392A (ja) * | 2006-02-15 | 2007-08-30 | Mitsumi Electric Co Ltd | チャンネルサーチ方法、及び、それを用いた通信装置 |
JP2008085650A (ja) * | 2006-09-27 | 2008-04-10 | Funai Electric Co Ltd | クライアント・サーバシステム |
JP2007174709A (ja) * | 2007-03-19 | 2007-07-05 | Matsushita Electric Works Ltd | 伝送システム |
Non-Patent Citations (1)
Title |
---|
See also references of EP2413646A4 |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2012175226A (ja) * | 2011-02-18 | 2012-09-10 | Sharp Corp | 多段中継ネットワーク、多段中継から成る無線テレメータシステム及び無線テレメータシステムに用いられる無線子機 |
CN103036813A (zh) * | 2011-09-30 | 2013-04-10 | 冲电气工业株式会社 | 中继单元 |
CN103036813B (zh) * | 2011-09-30 | 2016-06-15 | 冲电气工业株式会社 | 中继单元 |
JP2015503887A (ja) * | 2012-01-12 | 2015-02-02 | クアルコム,インコーポレイテッド | ワイヤレスネットワークを外部タイミングソースと同期させるための方法および装置 |
JPWO2014013667A1 (ja) * | 2012-07-19 | 2016-06-30 | パナソニックIpマネジメント株式会社 | 検針装置 |
JP2015023304A (ja) * | 2013-07-16 | 2015-02-02 | 富士電機株式会社 | 無線通信ネットワークシステム、常時動作無線端末、無線通信方法、および、プログラム |
WO2018180762A1 (ja) * | 2017-03-29 | 2018-10-04 | パナソニックIpマネジメント株式会社 | 無線通信装置、無線通信用プログラム、および中継器 |
Also Published As
Publication number | Publication date |
---|---|
JP5491507B2 (ja) | 2014-05-14 |
CN102474837B (zh) | 2015-08-19 |
CN102474837A (zh) | 2012-05-23 |
EP2413646A4 (en) | 2012-08-01 |
US20120057620A1 (en) | 2012-03-08 |
JPWO2011007567A1 (ja) | 2012-12-20 |
EP2413646A1 (en) | 2012-02-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5491507B2 (ja) | 無線通信装置、無線通信システム、および無線通信方法、並びにこの無線通信方法を実行させるプログラム | |
US8356431B2 (en) | Scheduling communication frames in a wireless network | |
US8379608B2 (en) | Radio communication method, radio communication system and wireless terminal | |
US11202242B2 (en) | Low power sensor node operation for wireless network | |
CN110115072B (zh) | 在时隙信道跳变网络中的低能量端点设备和父设备之间的同步 | |
EP2602945B1 (en) | Wireless communication system and wireless communication apparatus | |
KR20180068848A (ko) | 광역 에너지 하비스팅 센서 네트워크 배치를 위한 멀티-홉 네트워킹 프로토콜 | |
TW201424282A (zh) | 無線通信系統及使用於該通信系統之無線子機及無線主機 | |
JP2012015879A (ja) | 無線自動検針システムおよび方法 | |
JP2008099075A (ja) | センサネットワークシステム及びメディアアクセス制御方法 | |
JP2011101276A (ja) | 無線通信装置 | |
US20130215821A1 (en) | Radio communication system | |
US9398535B2 (en) | System and method for power saving in wireless communication apparatus | |
JP2001256583A (ja) | 自動検針システム | |
CN105357744A (zh) | 一种随机接入中继器、中继系统及其中继方法 | |
JP5347857B2 (ja) | 無線通信装置 | |
JP5023842B2 (ja) | 無線送信装置 | |
EP1770878B1 (en) | Method and system for time synchronization in communication networks | |
JP6051736B2 (ja) | 超小型地球局の節電装置及び節電方法 | |
EP2496030A1 (en) | Wireless communication apparatus, wireless communication method, and program | |
JP5691016B2 (ja) | 無線通信システム、無線端末及びプログラム | |
JP2007096667A (ja) | 遠隔監視装置 | |
JP5413269B2 (ja) | 無線通信装置、無線通信方法及びプログラム | |
JP5462608B2 (ja) | 無線通信システム | |
JP2010124041A (ja) | 無線中継装置 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 201080031769.X Country of ref document: CN |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 10799631 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2011522735 Country of ref document: JP Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2010799631 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 13320456 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |