CN107211397B

CN107211397B - Communication system

Info

Publication number: CN107211397B
Application number: CN201680009141.7A
Authority: CN
Inventors: 长坂峰宜; 古河宪一
Original assignee: Mitsumi Electric Co Ltd
Current assignee: Mitsumi Electric Co Ltd
Priority date: 2015-02-06
Filing date: 2016-02-04
Publication date: 2020-12-04
Anticipated expiration: 2036-02-04
Also published as: WO2016125496A1; JP2016146532A; JP6531410B2; CN107211397A

Abstract

A transmitter (10) transmits the same transmission data in a predetermined order through at least two channels in a predetermined interval in one transmission operation, acquires and stores information indicating the transmission channel order from a receiver (20), notifies the receiver of the current transmission channel order, and performs transmission of the same data and reception of the information indicating the transmission channel order from the receiver (20) by time division multiplexing at the predetermined interval while switching the order of the channel to be transmitted based on the initial setting order or the transmission channel order acquired from the receiver (20).

Description

Communication system

Technical Field

The present invention relates to a communication system including a transmitter and a receiver, wherein the transmitter includes a power generation device that converts mechanical energy into electric energy, transmits a wireless signal by using the electric energy as a power source, and the receiver receives the wireless signal transmitted by the transmitter.

Background

For example, patent document 1 and the like disclose a communication system in which a power generation device is provided in a transmitter.

In such a communication system, since the supply amount of electric energy regenerated by the power generation device is low, there are limitations as follows: [1] only the amount of electricity stored in the power storage device or the like, or [2] the unit time is limited, and the amount of electricity that can be used is limited compared to an AC power supply or a battery.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-126161

Disclosure of Invention

Problems to be solved by the invention

In the communication system in which the power generation device is provided in the transmitter as described above, since the available power is very limited, communication mediation for improving the reliability and communication capability of communication in conventional wireless communication cannot be performed, and for example, switching of the mutual communication channel by carrier sense based on bidirectional communication and retransmission with ACK failure cannot be performed, and communication is fixedly performed through a predetermined channel by using a unidirectional broadcast method.

Therefore, even in a channel that is not used by another wireless device or the like and can perform good communication, such as when the wireless device is installed, communication is blocked and communication does not reach the channel with an increase in the time for which the channel is occupied by an event that occurs after installation (bringing in a mobile phone or installing another communication device). Therefore, although it is conceivable to increase the arrival probability of communication by setting multiple transmission of a channel or the like in some devices, if a device that communicates with a high occupancy rate on the channel is located nearby, it cannot be said that the improvement effect of the arrival probability is actually obtained.

The present invention has been made in view of the above problems, and provides a communication system capable of improving reliability of communication even without performing a procedure such as carrier sense which has been complicated in the past, in a manner of performing communication through a good channel as always as possible and performing communication with limited energy.

Means for solving the problems

One embodiment of a communication system according to the present invention includes a transmitter having a power generation unit that converts mechanical energy into electric energy, and wirelessly transmits electric energy obtained by the power generation unit as a power source, and a receiver that receives a wireless signal transmitted by the transmitter,

the transmitter sequentially transmits the same transmission data in a predetermined order through at least two or more channels at predetermined intervals in one transmission operation, acquires and stores information indicating the transmission channel order from the receiver, notifies the receiver of the current transmission channel order, switches the order of the channel to be transmitted based on an initially set order or the transmission channel order acquired from the receiver, and performs transmission of the same data and reception of the information indicating the transmission channel order from the receiver by time division multiplexing at the predetermined intervals,

the receiver stores a reception channel number and a bit number, receives and stores a transmission channel number and a transmission channel bit number notified from the transmitter, transmits information indicating the transmission channel bit number to the transmitter, evaluates whether a reception channel is normally received or erroneously received, evaluates reception quality of each channel, switches the reception channel according to a preset bit number when erroneous reception is performed through a set channel, and notifies the transmitter of a transmission channel bit number to be transmitted next based on a result of evaluation of each channel.

One aspect of the communication system of the present invention is a unidirectional communication system including: a transmitter having a power generation section that converts mechanical energy into electric energy, performing wireless transmission using the electric energy obtained by the power generation section as a power source, and a receiver that receives a wireless signal transmitted by the transmitter,

the transmitter sequentially transmits the same transmission data in a determined order and at a determined interval through at least two channels in one transmission operation,

the receiver stores the transmission channel number and the transmission channel bit number of the transmitter, evaluates whether the reception channel is normally received or erroneously received, and switches the reception channel according to a preset bit number when the reception channel is judged to be busy.

the receiver stores the same channel number as the transmitter, evaluates the quality of the reception channel, and switches the reception channel when the quality of the reception channel is equal to or less than a predetermined value.

the receiver stores the transmission channel number and the transmission channel number of the transmitter, switches the reception channel in synchronization with the transmission interval by a timer, and switches the reception channel in a determined order to receive the multiple-transmitted data transmitted from the transmitter through different channels a plurality of times.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can realize a communication system that can always perform communication through a good channel and can perform communication with limited energy, and can improve the reliability of communication without performing procedures such as carrier sense that have been complicated conventionally.

Drawings

Fig. 1 shows a schematic configuration of a communication system according to an embodiment.

Fig. 2 shows the principle of the communication control method 1, fig. 2A shows the operation principle of the transmitter, and fig. 2B shows the operation principle of the receiver.

Fig. 3 is a flowchart showing a transmission processing flow of the transmitter in the communication control method 1.

Fig. 4 is a flowchart showing a flow of reception processing of the receiver in the communication control method 1.

Fig. 5 is a flowchart showing a processing flow of the reception start interrupt subroutine.

Fig. 6 shows the principle of the communication control method 2, fig. 6A shows the principle of the initial transmission operation of the transmitter, fig. 6B shows the principle of the operation of the receiver, and fig. 6C shows the principle of the initial transmission operation of the transmitter.

Fig. 7 is a flowchart showing a transmission processing flow of the transmitter in the communication control method 2.

Fig. 8 is a flowchart showing a flow of reception processing of the receiver in the communication control method 2.

Fig. 9 is a flowchart showing a processing flow of the reception start interrupt subroutine.

Fig. 10 is a flowchart showing a processing flow of the timer interrupt subroutine.

Fig. 11 shows the principle of the communication control method 3, fig. 11A shows the principle of the transmission operation of the transmitter, and fig. 11B shows the principle of the reception operation of the receiver.

Fig. 12 is a flowchart showing a flow of reception processing of the receiver in the communication control method 3.

Fig. 13 is a flowchart showing the flow of processing of the reception start interrupt subroutine.

Fig. 14 is a flowchart showing the flow of processing of the timer interrupt subroutine.

Fig. 15 is a flowchart showing a flow of reception processing of the receiver in the communication control method 4.

Fig. 16 is a flowchart showing the flow of processing of the reception start interrupt subroutine.

Fig. 17 is a flowchart showing a processing flow of the timer interrupt subroutine.

Detailed Description

With limited energy, the transmitting side cannot detect a good channel from among a plurality of channels, and the transmitter and receiver cannot mediate communication channels with each other. Therefore, the present embodiment proposes the following method: the transmitter does not perform mediation with the receiver, but asynchronously and sequentially multiplex-transmits the same data through a plurality of channels set in advance. The receiver generates sufficient power, detects the reception state, and switches the channel so that it can receive through another channel if the channel is busy.

In addition, the present embodiment proposes the following method: the receiver generates sufficient power, performs detection and evaluation of the reception state, performs reception through the reception channel with the best state, and instructs the transmitter of switching of the first channel (primary channel) with the least power (ACK reply) so that the communication probability is always the highest.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

< Structure >

Fig. 1 shows a schematic configuration of a communication system according to an embodiment. The communication system of the present embodiment is a communication system that performs one-way communication for transmitting data from one transmitter 10 having a power generation unit 14 to one or more receivers 20. The communication system is based on IEEE802.14.5 ZigBee wireless system, IEEE802.14.5 ZigBee Green Power wireless system, etc.

The transmitter 10 performs baseband processing such as encoding and transmission frame configuration by the baseband processing section 11, performs wireless processing such as amplification and up-conversion by the wireless transmission section 12, and transmits a wireless signal obtained thereby from an antenna. The operations of the baseband processing unit 11 and the radio transmission unit 12 are controlled by the transmission control unit 13. The transmitter 10 includes a power generation unit 14 that converts mechanical energy into electric energy and a power storage unit 15, and stores electric energy obtained by the power generation unit 14 in the power storage unit 15. The electric energy supplied to power storage unit 15 is energy for operating entire transmitter 10.

The receiver 20 performs radio processing such as amplification and down-conversion on a signal received via an antenna by a radio reception unit 21, and performs demodulation processing such as decoding by a baseband demodulation unit 22. The operations of the radio reception unit 21 and the baseband demodulation unit 22 are controlled by the reception control unit 23.

In the present embodiment, the communication between the transmitter 10 and the receiver 20 is controlled by any one of the communication control methods 1 to 4 described below, whereby the normal communication probability can be improved with low power consumption.

Further, the power generation unit 14 may have the following structure: having a coil and a permanent magnet; an accumulator for accumulating mechanical energy from outside such as human operation as elastic energy generated by deformation of an elastic body such as a spring; the mechanism for releasing elastic energy of the accumulator by a predetermined displacement input, and the relative displacement between the coil and the permanent magnet is changed by the released energy, so that the magnetic flux density passing through the coil is changed to generate electricity by electromagnetic induction.

Further, the power generation unit 14 may have the following structure: the magnetic resonance device is provided with at least one magnetostrictive rod which is made of magnetostrictive materials and enables magnetic lines of force to pass through in the axial direction; a beam member having a function of applying stress to the magnetostrictive rod; the coil is configured to cause magnetic lines of force to pass in an axial direction and generate a voltage in accordance with a change in density of the magnetic lines of force, and the coil is configured to store mechanical energy from outside in a direction substantially perpendicular to the axial direction with respect to one end of the magnetostrictive rod by displacing the other end with respect to the one end of the magnetostrictive rod in response to an operation of a human or the like, store the mechanical energy as elastic energy in the beam member and the magnetostrictive material, release a forced displacement of the other end by a predetermined displacement input, and cause the magnetostrictive rod to expand and contract by the stored elastic energy, thereby changing the density of the magnetic lines of force and generating a voltage in the coil.

The following terms used in the description of the present embodiment have the following meanings.

Primary channel (M-ch): the channel on which the transmitter 10 initially transmits. In addition, the channel on which the receiver 20 stands by.

Subchannel (S-ch): the transmitter 10 switches channels after performing M-ch transmission, and sequentially performs transmission. The receiver 20 temporarily switches the reception channel and performs backoff. A plurality of (S1-ch, S2-ch) may be set.

Sfd (start Frame detect): the reception frame to start data reception is notified of detection.

SFD _ INT: hardware interrupts generated at SFD reception.

And (3) LEN: next received frame after SFD, received data length.

SRC: FCF + SEQ + DES + Source PAN ID (destination address, Source address).

< communication control method 1>

Fig. 2 shows the principle of the communication control method 1. Fig. 2A shows the operation principle of the transmitter 10, and fig. 2B shows the operation principle of the receiver 20.

In the communication control method 1, as shown in fig. 2A, the transmitter 10 performs multiple transmission in which the same transmission data is sequentially transmitted through at least two or more channels in a predetermined order and at predetermined intervals in one transmission operation (meaning one broadcast transmission). In the example of fig. 2A, broadcast transmission is performed in multiplex on three channels.

As shown in fig. 2B, the receiver 20 demodulates the received channels in a predetermined order. Here, the receiver 20 stores the transmission channel number of the transmitter 10 and the number of bits for reception demodulation in advance, and sequentially performs reception demodulation on the channels in the stored order. The receiver 20 evaluates whether the channel subjected to reception demodulation is normal reception or erroneous reception, and immediately switches the reception channel in accordance with the bit number stored in advance when the channel is evaluated as erroneous reception. The example of fig. 2B is an example in which the first reception channel is erroneously received because another receiver 20 occupies the reception channel (i.e., is busy), the second reception channel is erroneously received because the ambient wave environment is poor, and the third reception channel is capable of normal reception. In this way, the time until normal reception is performed in a certain channel can be shortened, and the normal communication probability can be increased.

In addition, the evaluation of whether normal reception or erroneous reception is performed is determined as erroneous reception when any of the following 1) to 4) is satisfied, and is determined as normal reception when any of the following is not satisfied.

1) LEN is not a specified length.

2) The destination address and the source address do not conform to a predetermined set value or list

3) The CRC (checksum) of the received data is not true (OK).

4) The protocol, data range and format of the received data are not in the preset range.

Fig. 3 shows a transmission processing flow of the transmitter 10 in the communication control method 1.

The transmitter 10 starts transmission processing in step S10. The transmission process is started with a timer, or a voltage rise of power storage unit 15, a voltage detection of power storage unit 15, a sensor signal, an external signal, a switch, or the like as a trigger.

The transmitter 10 performs initial setting in step S11. Specifically, preparation of transmission data, setting of the number of transmission channels, and setting of the number of transmission times are performed. In step S12, a channel for this transmission is set, and in step S13, transmission is performed on this channel. The transmission count value of the transmission counter is incremented in step S14, and it is determined whether the number of transmissions (transmission count value) is greater than the set number in step S15. If an affirmative decision is made in step S15, the process proceeds to step S17 to end the transmission process, and if a negative decision is made in step S15, the process proceeds to step S12 after waiting for a predetermined time in step S16. As described above, the transmitter 10 repeats steps S12-S13-S14-S15-S16-S12, and as shown in fig. 2A, performs multiple transmission in which the same transmission data is sequentially transmitted through at least two or more channels in the determined order and at the determined intervals in one transmission operation (meaning one broadcast transmission).

In other words, the transmitter 10 determines M-ch and S-ch according to predetermined initial settings, and performs sequential transmission at least twice. Here, the transmission interval of each transmission packet is at least (time required for the receiver to switch the reception channel + the normal frame length) or more.

Fig. 4 shows a flow of reception processing of the receiver 20 in the communication control method 1.

When the reception process is started in step S20, the receiver 20 performs initial setting in step S21. Specifically, the bit order of the reception channel is acquired and set. The receiver 20 sets a reception channel in step S22, turns on the reception unit (i.e., the radio reception unit 21 and the baseband demodulation unit 22) in step S23, turns on the reception start interruption in step S24, and ends the reception process in step S25.

Fig. 5 shows a processing flow of the reception start interrupt subroutine. When the reception start interrupt is turned on in step S24 of fig. 4, the receiver 20 starts the reception start interrupt subroutine S30 of fig. 4, turns off the timer interrupt in step S31, and then the reception controller 23 evaluates whether or not normal reception is performed in step S32. Specifically, the items 1) to 4) above were evaluated.

Then, it is determined in step S33 whether or not the reception is erroneous. Specifically, the reception controller 23 determines that the reception is erroneous when any of the items corresponding to 1) to 4) is not satisfied (yes at step S33), and determines that the reception is normal when any of the items is not satisfied (no at step S33).

When it is determined in step S33 that reception is normal, it moves to step S34 to complete reception and store the demodulated data. Next, the current channel is set to the channel of the rank 1 in step S35, and the process returns to the main routine in step S36 (fig. 4).

On the other hand, when it is determined in step S33 that the channel is erroneously received, the process proceeds to step S37 to determine whether the set channel is the last bit. If the set channel is not the last order, the process proceeds to step S38, the reception channel is changed according to the set order, the process proceeds to step S39, the timer interrupt is started, and the process returns to the main routine in step S36 (fig. 4). When the channel is set to the final order, the process proceeds from step S37 to step S40, the reception channel is set to the order 1, the timer interrupt is turned off in step S41, and the process returns to the main routine in step S36 (fig. 4).

As described above, according to the communication control method 1, the transmitter 10 sequentially transmits the same transmission data through at least two or more channels in the determined order and at the determined intervals in one transmission operation, and the receiver 20 stores the transmission channel number and the transmission channel bit number of the transmitter 10, evaluates whether the reception channel is normally received or erroneously received, and switches the reception channel according to the preset bit number when the reception channel is determined to be busy.

This can shorten the time until normal reception is performed in a certain channel, and can improve the normal communication probability.

In addition, the transmitter 10 may repeat transmission at least twice through more than two channels and in the decided order.

The interval (cycle) between frames in the multiple transmission by the transmitter 10 may be equal to or longer than the time required for the receiver 20 to switch channels + the time required for normal frame reception + the received frame evaluation time.

The receiver 20 may receive any packet, sequentially evaluate information included in the received frame using recognition of reception interruption (start of frame) as a trigger, and evaluate erroneous reception in a plurality of stages.

Further, after the receiver 20 switches the reception channel to the next channel set by the error, the channel is set to at least (set channel number +1) × normal frame time + set channel number × transmission interval + blank, and when the time elapses and reception interruption does not occur, the reception channel can be restored to the original channel. Alternatively, switching to a plurality of channels may be performed when the channels are sequentially set, and thereafter, if there is no reception interruption in the finally set channel, the initial channel may be similarly restored.

< communication control method 2>

Fig. 6 shows the principle of the communication control method 2. Fig. 6A shows the principle of the initial transmission operation of the transmitter 10, fig. 6B shows the principle of the operation of the receiver 20, and fig. 6C shows the principle of the initial transmission operation of the transmitter 10.

In the communication control method 2, as shown in fig. 6A, the transmitter 10 performs multiple transmission in which the same transmission data is sequentially transmitted through at least two or more channels in a predetermined order and at predetermined intervals in one transmission operation (meaning one broadcast transmission), similarly to the communication control method 1 described above. In the example of fig. 6A, broadcast transmission is performed in multiplex on three channels. Each transmission frame includes data and transmission-side PHY information (setting and bit order of M-ch and S-ch).

In addition, in the communication control method 2, the transmitter 10 receives ACK from the receiver 20 after transmitting each transmission frame. The transmission interval of each transmission frame is set to at least a time period during which ACK can be received from RX, and in the present embodiment, is set to a time period defined by ieee802.15.4. After each transmission frame is transmitted, the transmitter 10 receives the ACK from the receiver 20, and thus becomes a reception state until the next transmission time.

As shown in fig. 6B, the receiver 20 demodulates the received channels in sequence in a predetermined order, as in the communication control method 1 described above. Here, the receiver 20 stores the transmission channel number of the transmitter 10 and the number of bits for reception demodulation, and sequentially performs reception demodulation on the channels in the stored order. The receiver 20 evaluates whether the channel subjected to reception demodulation is normal reception or erroneous reception, and immediately switches the reception channel in accordance with the bit number stored in advance when the channel is evaluated as erroneous reception. The example of fig. 6B is an example in which the first reception channel is erroneously received because another receiver 20 occupies the reception channel (i.e., is busy), the second reception channel is erroneously received because the ambient wave environment is poor, and the third reception channel is capable of normal reception. Up to this point, the same as the communication control method 1 described above is applied.

In addition, in the communication control method 2, the receiver 20 evaluates the reception quality of each channel, and when normal reception is completed, the receiver switches the M-ch of the transmitter 10 by returning ACK to the transmitter 10 through the channel (i.e., the channel on which normal reception has been performed).

As a result, as shown in fig. 6C, the transmitter 10 increases the transmission bit number of the channel to which the ACK is returned to perform transmission at the next transmission. The receiver 20 sets the channel to which the ACK is returned as the reception channel to which the ACK is first received, and waits for the next reception. That is, the transmitter 10 increases the transmission bit number of the channel having a high possibility of normal reception, and the receiver 20 waits for channel reception by the same bit number. This can shorten the processing time required for normal reception as compared with the communication control method 1, and can realize communication with lower power consumption.

Fig. 7 shows a transmission processing flow of the transmitter 10 of the communication control method 2.

The transmitter 10 starts transmission processing in step S50. The transmission process starts with a timer, a voltage rise of power storage unit 15, a voltage detection of power storage unit 15, a sensor signal, an external signal, a switch, and the like as triggers.

The transmitter 10 performs initial setting in step S51. Specifically, preparation of transmission data, setting of the number of transmission channels, and setting of the number of transmission times are performed. In step S52, a channel for the current transmission is set, and in step S53, the channel is transmitted. At this time, the transmitting side PHY information (setting and bit order of M-ch, S-ch) is transmitted in addition to the data. Next, the receiver is turned on in step S54 (although the transmitter 10 has no receiver in the configuration of fig. 1, the transmitter 10 needs to have a receiver in order to implement the communication control method 2), and the ACK is received from the receiver 20 in step S55.

If it is determined in step S56 that the ACK reception has timed out, the process moves to step S57 and stores the channel on which the ACK was received, and in step S58, the transmission order is changed according to the channel on which the ACK was received and the changed transmission order is stored. Then, the beam transmission processing is ended in step S59.

On the other hand, when it is determined in step S56 that the ACK reception has timed out, the process proceeds to step S60, the transmission count value of the transmission counter is incremented, and it is determined in step S61 whether or not the number of transmissions (transmission count value) is greater than the set number. If an affirmative decision is made in step S61, the process proceeds to step S59 to end the transmission process, and if a negative decision is made in step S61, the process proceeds to step S52 after waiting for a predetermined time in step S62. As described above, the transmitter 10 repeats steps S52-S53-S54-S55-S56-S60-S61-S62-S52, and as shown in fig. 6A, performs multiple transmissions in which the same transmission data is sequentially transmitted through at least two or more channels in the determined order and at the determined intervals, and a reception operation of ACK in one transmission operation (meaning one broadcast transmission).

The transmitter 10 sets the channel to which the ACK is returned as M-ch to be transmitted next time, and updates the PHY information to notify the switching operation.

Fig. 8 shows a flow of reception processing of the receiver 20 in the communication control method 2.

When the reception process is started in step S70, the receiver 20 performs initial setting in step S71. Specifically, the bit order of the reception channel is acquired and set. The receiver 20 sets the reception channel in step S72, turns on the reception unit and turns on the reception start interrupt in step S73, turns on the timer interrupt in step S74, and ends the reception process in step S75.

Fig. 9 shows a processing flow of the reception start interrupt subroutine. When the receiver 20 turns on the reception start interrupt in step S73 of fig. 8, the reception start interrupt subroutine S80 of fig. 9 is started, and the reception controller 23 evaluates whether or not the reception is normal in step S81. Specifically, the items 1) to 4) above were evaluated.

Then, it is determined in step S82 whether or not the reception is erroneous. When it is determined in step S82 that normal reception is performed, the process moves to step S83 to complete data reception and store the demodulated data.

Next, the current PHY information is compared with the current reception channel in step S84, and when it is determined in step S84 that the current PHY information is not the same as the current reception information, the process moves to step S86 and an ACK is returned through the current reception channel. On the other hand, if it is determined that the current PHY information is the same as the current reception channel, the flow proceeds to step S87 to return to the main routine (fig. 8).

When it is determined in step S82 that the reception is erroneous, the process proceeds to step S88, and the reception channel is changed to the next reception channel in accordance with the set bit number. Then, after the channel order is determined again in step S89, the program returns to the main routine in step S87 (fig. 8).

Fig. 10 shows a processing flow of the timer interrupt subroutine. When the timer interrupt is turned on in step S74 of fig. 8, the receiver 20 starts the timer interrupt subroutine S90 of fig. 10, measures RSSI (Received Signal Strength Indicator) in step S91, evaluates the Received channel quality based on the RSSI measured in step S92, stores the evaluation result, determines channel switching and determines the channel order in step S93, and returns to the main routine (fig. 8) in step S94.

As the index for evaluating the quality of the reception channel, RSSI at normal reception, RSSI of an SFD frame at erroneous reception, error occurrence frequency and history of each channel, RSSI in a standby state of each channel, and the like can be used. The RSSI at the normal reception is a value corresponding to the distance between the transmitter 10 and the receiver 20, the presence or absence of an obstacle, or the like, and the higher the RSSI, the better the reception quality. The RSSI of the SFD frame at the time of error reception is a value corresponding to the influence exerted on the receiver 20 by other devices, and the reception quality is deteriorated as the RSSI is larger. The RSSI in the standby state of each channel is a value corresponding to noise around the receiver, and the higher the RSSI is, the worse the reception quality is.

As described above, according to the communication control method 2, the transmitter 10 sequentially transmits the same transmission data through at least two or more channels in the determined order and at the determined intervals in one transmission operation, acquires and stores information indicating the transmission channel order from the receiver 20, notifies the receiver of the current transmission channel order, and performs transmission of the same data and reception of the information indicating the transmission channel order from the receiver 20 by the time division multiplexing method at the determined intervals while switching the order of the channel to be transmitted based on the initially set order or the transmission channel order acquired from the receiver 20.

On the other hand, the receiver 20 stores the reception channel number and the bit number, receives and stores the transmission channel number and the transmission channel bit number notified from the transmitter 10, transmits information indicating the transmission channel bit number to the transmitter 10, evaluates whether the reception channel is normally received or erroneously received, evaluates the reception quality of each channel, switches the reception channel according to the preset bit number when the erroneous reception is performed in the set channel, and notifies the transmitter of the transmission channel bit number to be transmitted next based on the result of evaluating each channel.

This can shorten the time until normal reception is performed on a certain channel, and can improve the normal communication probability.

In addition, the transmitter 10 may repeat transmission and reception at least twice in the decided order through two or more channels.

The transmitter 10 may maintain the reception state after the transmission in accordance with the determined channel order for a certain period of time, and receive a reception completion notification from the receiver 20 during this period of time, thereby storing the channel as the first transmission channel at the time of the next transmission and changing the transmission channel order.

The receiver 20 may evaluate the reception quality of each channel by evaluating any one or a combination of evaluation items of the evaluation items described below, and after completing normal reception, return the reception completion through the channel, thereby instructing the transmitter 10 to transmit the next first transmission channel.

Completion of normal reception in the channel

RSSI (reception sensitivity) at normal reception

RSSI (reception sensitivity) of SFD frame at the time of error reception

Error occurrence frequency and history of each channel

The interval (cycle) between frames in the multiple transmission/reception by the transmitter 10 may be equal to or longer than the time required for the receiver 20 to switch channels + the time required for the normal frame reception + the received frame evaluation time or the reception completion notification from the receiver 20.

After the receiver 20 switches the reception channel to the next channel, the error is detected, and the reception channel is set to at least (the number of channels +1) × the normal frame time + the number of channels × the transmission interval + the blank, and the reception channel is returned to the original channel when the reception interruption does not occur even after the lapse of the time. Alternatively, switching to a plurality of channels may be performed when the channels are sequentially set, and thereafter, if there is no reception interruption in the finally set channel, the initial channel may be similarly restored.

< communication control method 3>

Fig. 11 shows the principle of the communication control method 3. Fig. 11A shows the principle of the transmission operation of the transmitter 10, and fig. 11B shows the principle of the reception operation of the receiver 20.

In the communication control method 3, as shown in fig. 11A, the transmitter 10 performs multiple transmission in which the same transmission data is sequentially transmitted through at least two or more channels in a predetermined order and at predetermined intervals in one transmission operation (meaning one broadcast transmission), similarly to the communication control method 1 described above. In the example of fig. 11A, broadcast transmission is performed in multiple in three channels.

As shown in fig. 11B, the receiver 20 demodulates the received channels in sequence in a predetermined order, as in the communication control method 1 described above. Here, the reception is continued through the reception channel until the quality of the reception channel becomes equal to or lower than a predetermined value, and the next reception channel is switched to when the quality of the reception channel becomes equal to or lower than the predetermined value.

The transmission processing flow of the transmitter 10 of the communication control method 3 is the same as the transmission processing flow of the transmitter 10 in the communication control method 1 described above (fig. 3).

Fig. 12 shows a flow of reception processing of the receiver 20 in the communication control method 3.

When the reception process is started in step S100, the receiver 20 performs initial setting in step S101. Specifically, the bit order of the reception channel is acquired and set. The receiver 20 sets a reception channel in step S102, turns on the reception unit and turns on the reception start interrupt in step S103, turns on the timer interrupt in step S104, and ends the reception process in step S105.

Fig. 13 shows a processing flow of the reception start interrupt subroutine. When the receiver 20 turns on the reception start interruption in step S103 in fig. 12, the reception start interruption subroutine S110 in fig. 13 is started, and the RSSI is acquired (measured) and stored in step S111. Next, in step S112, the reception control unit 23 evaluates whether or not the reception is normal. Specifically, the items 1) to 4) above were evaluated.

Then, it is determined in step S113 whether or not the reception is erroneous. When it is determined in step S113 that the reception is normal, the process proceeds to step S114 to complete the data reception and store the demodulated data. Next, the quality of the normal reception channel is evaluated in step S115, the evaluation result is stored, and the routine returns to the main routine (fig. 12) in step S116.

When it is determined in step S113 that the reception is erroneous, the process proceeds to step S117 to evaluate the quality of the reception channel and store the evaluation result. Next, in step S118, channel switching is determined, and channel order is determined. Next, it is determined whether or not the channel switching is correct in step S119, and if not, the process proceeds to step S116, and if correct, the reception channel is changed to the next channel in step S120, and then the process proceeds to step S116.

Fig. 14 shows a processing flow of the timer interrupt subroutine. When the receiver 20 turns on the timer interrupt in step S104 in fig. 12, the timer interrupt subroutine S130 in fig. 14 is started, and the RSSI is measured and stored in step S131. In step S132, the received channel quality is evaluated based on the RSSI measured in step S131, the evaluation result is stored, and in step S133, channel switching is determined and the channel order is determined. It is then determined in step S134 whether or not the channel switching is correct, and if not, it moves to step S135 to return to the main routine (fig. 12). If correct, the reception channel is changed to the next channel in step S136, and the process proceeds to step S135.

In this manner, the receiver 20 performing the communication control method 3 detects the environmental noise and the reception intensity by the SFD interrupt and the timer interrupt, and when it is determined from the evaluation of the channel quality that it is necessary to switch the reception channel, the reception channel is promptly switched to the S-ch and the subsequent channels according to the evaluation.

As described above, according to the communication control method 3, the transmitter 10 sequentially transmits the same transmission data through at least two or more channels in the determined order and at the determined intervals in one transmission operation, the receiver 20 stores the same channel number as the transmitter 10, evaluates the quality of the reception channel, and switches the reception channel when the quality of the reception channel is equal to or less than a predetermined value.

The receiver 20 may measure the received signal power at the channel being set, store it as the received strength (RSSI), compare the RSSI at the time of receiving data from the transmitter 10 with the RSSI of the noise signal at the time of standby, and perform the operation of switching the channel when the difference is equal to or smaller than a predetermined value.

The receiver 20 may continuously store the RSSI, compare the current communication probability of the channel in the setting with the communication probability history of other channels used in the past, predict the effect after channel switching in advance, and determine whether or not to switch and which channel to switch to.

The receiver 20 may continuously store a plurality of pairs of the RSSI and the time history of the detection thereof, and may determine the switching to the channel by using the RSSI of the set channel and the RSSI of another channel used in the past by using a prediction method such as the average shift method, the nearest neighbor method, or the exponential smoothing method, alone or in combination.

In the multiple transmission in which the transmitter 10 sequentially transmits data, when the number of times of multiple transmission is set to at least three, the time required for data transmission of one channel is set to tT, the transmission interval of multiple transmission is set to tD, and the minimum interval at which the receiver 20 switches channels is set to tE, the transmission and reception channels can be prevented from missing each other and losing the reception opportunity by setting tE to tD +2 × tT or more.

Further, by setting the number of times of multiplex transmission to at least four times and setting the transmission channels of the even number and the odd number to be the same, it is possible to generate a reception opportunity of the channel in at least one reception period.

< communication control method 4>

The communication control method 4 does not make a determination that it does not make sense to wait because the current reception channel is busy, as in the communication control method 1 described above. The communication control method 4 switches the channel if any reception is obtained, so that normal reception can be performed in a plurality of channels, thereby increasing the probability of normal reception.

The transmission sequence of the transmitter 10 is the same as the communication control method 1.

The receiver 20 performs the following processing.

The M-ch is set as a reception channel according to a predetermined initial setting.

Any reception is detected by the SFD interrupt, and the reception channel is maintained for a certain time regardless of erroneous reception.

Wait until the next transmission timing, and switch the reception channel.

Wait for a predetermined time even after S-ch and S-ch, and automatically switch channels.

The time to wait after S-ch and S-ch is (set number of ch +1) × frame time + set number of ch × transmission interval + blank.

After switching to the final channel, the M-ch returns to stand by.

Fig. 15 shows a flow of reception processing of the receiver 20 in the communication control method 4.

When the reception process is started in step S140, the receiver 20 performs initial setting in step S141. Specifically, the bit order of the reception channel is acquired and set. The receiver 20 sets a reception channel in step S142, turns on the reception section and turns on the reception start interrupt in step S143, and ends the reception process in step S144.

Fig. 16 shows a processing flow of the reception start interrupt subroutine. When the reception start interruption is turned on in step S143 of fig. 15, the receiver 20 starts the reception start interruption subroutine S150 of fig. 16, turns on the timer interruption in step S151, and then the reception control unit 23 evaluates whether or not normal reception is performed in step S152. Specifically, the items 1) to 4) above were evaluated.

Then, it is determined in step S153 whether or not the reception is erroneous. Specifically, the reception control unit 23 determines that the reception is erroneous in any one of the items corresponding to 1) to 4) (yes in step S153), and determines that the reception is normal in any one of the items not corresponding to 1) to 4) (no in step S153).

When it is determined in step S153 that reception is normal, the process moves to step S154 to complete reception and store the demodulated data. The timer interrupt is turned off in step S155, the current channel is set to the channel of the bit 1 in step S156, and the routine returns to the main routine in step S157 (fig. 15).

On the other hand, if it is determined in step S153 that the reception is erroneous, the routine proceeds to step S157 to return to the main routine (fig. 15).

Fig. 17 shows a processing flow of the timer interrupt subroutine. When the timer interrupt is turned on in step S151 of fig. 16, the receiver 20 starts the timer interrupt subroutine S160 of fig. 17, determines whether or not the set channel is the final bit in step S161, moves to step S162 and changes the reception channel according to the set bit if the set channel is not the final bit, and returns to step S164 after the timer interrupt is turned on in step S163. On the other hand, when it is determined in step S161 that the set channel is the last order, the process proceeds to step S165, the set channel is set to the 1-order channel, the timer interrupt is turned off in step S166, and the process returns to step S164.

As described above, according to the communication control method 4, the transmitter 10 sequentially transmits the same transmission data through at least two or more channels in the determined order and at the determined intervals in one transmission operation, the receiver 20 stores the transmission channel number and the transmission channel order of the transmitter 10, switches the reception channel in synchronization with the transmission interval by the timer, switches the reception channel in the determined order, and receives the multiple transmission data transmitted from the transmitter 10 through different channels a plurality of times.

The receiver 20 may measure the signal power received in a channel under the setting, compare the measured signal power with a preset value as the reception intensity (RSSI), receive a certain radio wave by the receiver 20, and trigger the channel switching procedure when the RSSI at the time of reception is equal to or greater than the set value.

The above-described embodiments are merely specific examples for carrying out the present invention, and the technical scope of the present invention is not to be construed in a limiting manner. That is, the present invention can be implemented in various forms without departing from the spirit and the main characteristics thereof.

In this application, the entire disclosures of the specification, drawings and abstract of the specification included in japanese application laid-open at japanese application No. 2015-022198, filed on 6/2/2015 are cited.

Industrial application

The present invention is applicable to a communication system including a transmitter having a power generation unit that converts mechanical energy into electric energy, and wirelessly transmitting electric energy obtained by the power generation unit as a power source, and a receiver that receives a wireless signal transmitted by the transmitter.

Description of the symbols

10: transmitter

11: baseband processing unit

12: wireless transmitter

13: transmission control unit

14: power generation unit

15: power storage unit

20: receiver with a plurality of receivers

21: wireless receiving unit

22: base band demodulation unit

23: a reception control unit.

Claims

1. A communication system having a transmitter having a power generation section that converts mechanical energy into electric energy, and performing wireless transmission using the electric energy obtained by the power generation section as a power source, and a receiver that receives a wireless signal transmitted by the transmitter,

the transmitter sequentially transmits the same transmission data in a determined order through two or more channels at a determined interval in one transmission operation, acquires and stores information indicating the transmission channel order from the receiver, notifies the receiver of the current transmission channel order, switches the order of the channel to be transmitted based on an initially set order or the transmission channel order acquired from the receiver, and performs transmission of the same transmission data and reception of the information indicating the transmission channel order from the receiver by time division multiplexing at the determined interval,