JP2008236602A - Radio transmitter and radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transmit at least one of telegrams sent a prescribed number of times in advance to a receiver even if two or more sensors start to send sensor information simultaneously when the transmission time interval of each sensor is the same. <P>SOLUTION: When the repetition transmission time of a sensor 2b is set to a time T1, that of a sensor 2a is set to a time T2, and a telegram length (time required from the start of the transmission of one telegram by the sensors 2a, 2b to the completion of the transmission) is set to t, the sensor 2a sets the time T2 so that a formula of T2≥T1+2×t is satisfied. From the time T2 set based on the formula and the number k of times for transmitting the telegram in the repetition transmission operation of the sensor 2a, a transmission time interval Δt of a telegram by the sensor 2a is calculated by a formula Δt=T2/(k-1). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention detects information related to a predetermined environment, wirelessly transmits the detection information, and wireless reception that receives detection information transmitted from the sensor and performs a predetermined operation based on the detection information. The present invention relates to a technical field of a wireless communication system including a device.

  In recent years, with the advancement of circuit technology, the power saving of sensors and wireless circuits has resulted in the realization of wireless sensors (hereinafter simply referred to as sensors) that combine various sensors and wireless circuits. A wireless communication system that collects information detected by the sensor wirelessly is widely known. FIG. 11 shows the configuration of a conventional typical network system.

  As shown in FIG. 11, the wireless communication system 100 includes sensors 102 to 105 including detection units 102a to 105a, wireless transmission units 102b to 105b, and batteries 102c to 105c, a wireless reception unit 101a, a control unit 101b, and an I / O. And a receiver 101 provided with F101c. When the detection units 102a to 105a and the wireless transmission units 102b to 105b of the sensors 102 to 105 receive power from the batteries 102c to 105c and the detection signal levels of the detection units 102a to 105a exceed a predetermined threshold, the wireless transmission unit Sensor information including detection values is modulated into radio waves and transmitted from 102b to 105b. Receiving the radio waves from the sensors 102 to 105, the receiver 101 amplifies and demodulates the radio waves by the wireless receiving unit 101a to extract sensor information, and stores and analyzes the sensor information by the control unit 101b. To send the sensor information to the external system.

  As shown in FIG. 12, the wireless communication system 100 further includes repeaters 106 and 107, and sensor information transmitted from a sensor (here, referred to as sensor 102) passes through the repeaters 106 and 107 in order. As a sensor information transmission method in such a wireless communication system 100, a method as shown in FIG. 13 is known.

  In the transmission method shown in FIG. 13, when sensor information is transmitted from the sensor 102, the sensor information is relayed in the order of the repeater 106 and the repeater 107 and then received by the receiver 101. Further, the sensor 102 repeatedly transmits the same sensor information a predetermined number of times at a predetermined transmission interval. In this way, the same sensor information is repeatedly transmitted a predetermined number of times because it is expected that any sensor information will be transmitted to the receiver 101 even if external noise may interfere with the transmission and reception of the sensor information. Is. That is, the sensor information transmitted from the sensor 102 is not received by the repeater 106 as indicated by the arrow X1 in FIG. 13, or the sensor information transmitted from the repeater 106 is not received as indicated by the arrow X2 in FIG. Even when the repeater 107 does not receive the signal, it is expected that the sensor information transmitted to the receiver 101 exists at another timing as shown by the arrows X3 and X4 in FIG. Information is repeatedly transmitted a predetermined number of times.

  When the receiver 101 confirms that the same sensor information is transmitted from the sensor 102 a predetermined number of times, the receiver 101 determines that the sensor 102 indicates that the detection target has been detected by the sensor 102, and the sensor 101 Send information to an external system.

In Patent Document 1 below, in a one-way communication system in which a series of information to be transmitted is divided into information blocks of a predetermined number of bits and the same information block is placed, the frame is added to the frame. A technique is disclosed that includes the number of times of continuous transmission indicating how many times frame transmission of the same information block is repeatedly transmitted.
Japanese Patent Laid-Open No. 5-160815

  In the transmission method shown in FIG. 13, when the transmission interval of each sensor is the same, when two or more sensors start transmitting the sensor information substantially simultaneously, the transmission timing of the message by each sensor is substantially the same. As a result, the telegrams transmitted from the sensors collide with each other in the repeater or the receiver, and the sensor information is not received by the receiver 101.

  The present invention has been made to solve the above-described problems, and is a case where the transmission intervals of the sensors are the same, and two or more sensors start transmitting sensor information at the same time. However, at least one of the messages transmitted a predetermined number of times is transmitted to the receiving device.

  The invention according to claim 1 is a wireless transmitter that creates information and performs a transmission operation that repeats the information a predetermined number of times at predetermined intervals as a message, and the time required for the wireless transmitter to transmit one message Is a message length t, and a time required for another wireless transmitter to perform the transmission operation is represented as a time T1, a time T2 required for the wireless transmitter to perform the transmission operation is expressed as T2 ≧ T1 + 2 × t. The transmission interval of the message is set based on the time T2 and the predetermined number of times.

  According to the present invention, by setting the time T2 so as to satisfy T2 ≧ T1 + 2 × t, even when a plurality of wireless transmitters start transmitting messages simultaneously, at least one message is transmitted. It is possible to avoid that the period overlaps with the transmission period of the message by another wireless transmitter.

  That is, when the transmission start timing of the message by the wireless transmitter and the transmission start timing of the message by another wireless transmitter are the same, the transmission delay is 2 × t from the transmission start timing of the last message by another wireless transmitter. Then, the wireless transmitter starts transmission of the last message. In this case, at least the last telegram does not overlap the transmission period with the transmission period of the telegram by another wireless transmitter.

  If the transmission start timing of the message by the wireless transmitter is delayed by the message length t from the transmission start timing of the message by another wireless transmitter, the transmission start timing of the last message by the other wireless transmitter The wireless transmitter starts transmission of the last telegram after 3 × t. Also in this case, at least the last telegram does not overlap the transmission period with the transmission period of the telegrams by other wireless transmitters.

  Furthermore, even if the transmission start timing of the message by the wireless transmitter is earlier by the message length t than the transmission start timing of the message by another wireless transmitter, the transmission start timing of the last message by another wireless transmitter is 1 The wireless transmitter starts transmitting the last telegram after a delay of xt. Therefore, also in this case, at least the last message does not overlap the transmission period with the transmission period of the message by another wireless transmitter.

  In this way, even if the transmission start timing of the message by the wireless transmitter is advanced or delayed with respect to the transmission start timing of the message by another wireless transmitter, the transmission period is always set to another wireless transmission. At least one message that does not overlap the message transmission period by the device is generated. Therefore, at least one electronic message can be transmitted to the wireless reception device without colliding with an electronic message transmitted from another wireless transmitter.

  At that time, as in the invention described in claim 2, the remainder obtained by dividing the identification information assigned to the wireless transmitter for individually identifying the wireless transmitter by an integer is multiplied by 2. When the number is a coefficient n, the time T2 is calculated by T2 = T1 + n × t, and the predetermined number of times is k, the message transmission interval Δt is calculated by Δt = T2 / (k−1). Then, the transmission interval of a message can be determined using information (identification information) that has already been used without storing or using new information to determine the transmission interval of the message.

  The wireless receiving device includes not only a receiver that finally transmits a message, but also a relay that relays a message between the wireless transmitter and the receiver.

  The invention according to claim 3 is a wireless transmitter that creates information, performs a transmission operation that repeats the information a predetermined number of times as a telegram, and a wireless reception device that receives transmission information from the wireless transmitter; A wireless communication system comprising: a wireless communication system, wherein the wireless transmitter is the wireless transmitter according to claim 1.

  According to the present invention, in the wireless communication system, the operation according to the first or second aspect of the invention can be obtained.

  According to a fourth aspect of the present invention, in the wireless communication system according to the third aspect, the wireless transmitter includes a sensor unit that detects environmental information, and the telegram identifies a type of the wireless transmitter. Detection information indicating the detection value of the first wireless transmitter, including identification information and detection information indicating the detection value related to the environment information, and a second wireless transmitter of a type different from the first wireless transmitter Detection information indicating the detection value of the wireless transmitter is configured by the same signal, the wireless reception device stores in advance the correspondence between the combination of the identification information and the detection information and the detection content of the wireless transmitter, When a message is received, the detection content of the wireless transmitter is interpreted based on the identification information and detection information included in the message.

  According to this invention, the detection information indicating the detection value of the first wireless transmitter and the detection information indicating the detection value of the second wireless transmitter of a different type from the first wireless transmitter are the same signal. The correspondence relationship between the combination of the identification information and detection information and the detection content of the wireless transmitter is stored in advance, and when the wireless reception device receives the electronic message, the identification information and detection information included in the electronic message Because the detection contents of the wireless transmitter are interpreted based on the information, it is not necessary to describe the information indicating the type of the wireless transmitter or the information indicating the expression format of the detected value in the message, and include it in the message. The amount of information can be reduced as much as possible.

  According to the present invention, even when the transmission intervals of the respective wireless transmitters are the same, and even when two or more wireless transmitters start transmitting a message at the same time, they are transmitted a predetermined number of times. At least one of the electronic messages can be transmitted to the wireless receiver.

  An embodiment of a wireless communication system according to the present invention will be described. FIG. 1 is a diagram illustrating an example of a wireless communication system according to the present invention.

(First embodiment)
A wireless communication system 1 according to the present invention is applied to buildings such as houses and offices for the purpose of crime prevention, disaster prevention, improvement of facility convenience, etc. As shown in FIG. To 2h), a repeater 3 (3a, 3b) and a receiver 4. In addition, FIG. 1 has shown what assumed the two-story building and the garage adjacent to it as an example of the installation object of the radio | wireless communications system 1. FIG.

  The sensor 2 includes, for example, human body sensors 2a to 2c and 2f for detecting a human body using infrared rays as a detection medium, security sensors 2d and 2e installed for the purpose of crime prevention, smoke sensors 2g and 2h installed for the purpose of disaster prevention, and the like. It is.

  The human body sensors 2a to 2c are provided, for example, for detecting the heat of the human body and controlling the operation of the lighting device 5 or an air conditioning device (not shown) according to the presence or absence of the human body, for example. For example, when the human body is detected by the human body sensors 2a to 2c, the receiver 4 turns on the lighting device 5 or operates the air conditioner. When no human body is detected, the receiver 4 turns off the lighting device 5. Or turn off the air conditioner. In addition, in FIG. 1, the human body sensors 2a-2c have shown the aspect installed in the indoor and garage of each floor.

  The security sensors 2d and 2e are a magnet sensor that performs a detection operation using magnetism, an acceleration sensor configured using a gyro, a capacitance type, a vibration sensor using an eddy current or a piezoelectric element, and the like. It is installed in a window 6 that can communicate with the outdoors, and detects opening / closing operation and vibration of the window when it is absent. In addition, in FIG. 1, the aspect by which the security sensors 2d and 2e are each installed in the window 6 provided in each floor is shown. The receiver 4 receives a notification that the opening / closing operation and vibration of the window 6 have been detected by the security sensors 2d and 2e, and outputs an alarm from the speaker 7 or the like.

  The smoke sensors 2g and 2h are installed, for example, on the ceiling, and are provided for disaster prevention (providing an alarm when a fire occurs) by detecting the presence of smoke. FIG. 1 shows a mode in which the smoke sensor is installed on the ceiling of each floor. The receiver 4 receives a notification that the presence of smoke exceeding a predetermined concentration is detected by the smoke sensors 2g and 2h, and outputs an alarm from the speaker 7 or the like.

  FIG. 2 is a block diagram showing an electrical configuration of the sensor 2. The sensor 2 includes a detection unit 8 that outputs an environmental detection signal obtained by using a detection medium corresponding to the type of the sensor 2 to the control unit 9, and a signal level of the detection signal output from the detection unit 8. Exceeds the predetermined threshold, the control unit 9 outputs sensor information indicating that to the wireless transmission unit 10 at a predetermined transmission cycle, and modulates the electronic message output from the control unit 9 into a radio wave. Is transmitted from the transmitting antenna 11 to the repeater 3 or the receiver 4. Hereinafter, the operation of wirelessly transmitting a message to the repeater or receiver 4 at a predetermined transmission cycle is referred to as a repeated transmission operation. Note that the detection unit 8, the control unit 9, and the wireless transmission unit 10 operate with electric power supplied from the battery 12.

  The control unit 9 is composed of, for example, a microcomputer incorporating a ROM for storing a control program, a RAM for temporarily storing data, and the like. Moreover, the control part 9 has a function as a message | telegram production | generation part which produces | generates the message | telegram which has a structure as demonstrated, for example, if the signal level of the detection signal acquired by the detection part 8 exceeds a predetermined threshold value, for example. FIG. 3 is a diagram illustrating a configuration example of a message.

  As shown in FIG. 3, the telegram 13 includes a preamble (PR), a unique word (UW), identification information (ID), data (DATA), and an error correction code (CRC). The preamble (PR) area is an area in which a bit synchronization pattern configured by repeating digital signals “1” and “0” is written. The repeater 3 and the receiver 4 synchronize with the bit rate of the message based on the bit synchronization pattern written in the preamble (PR) area of the message 13 being received.

  In the unique word (UW) area, a fixed bit string, for example, 8 bits or 16 bits, defined in advance between the sensor 2 and the repeater 3 or the receiver 4 is stored as a unique word pattern. It is. The repeater 3 or the receiver 4 can identify the start position of the message by detecting the unique word pattern.

  The area of identification information (ID) is an area in which an ID assigned as a unique number for each sensor 2 is stored. The repeater 3 can determine whether the telegram 13 is received or can specify the sensor 2 based on the ID written in the identification information (ID) area. The data (DATA) area is an area in which detection information indicating the detected content (detection value) is written. The error correction code (CRC) area is an area used for detecting bit errors in the identification information (ID) area and the data (DATA) area.

  Returning to FIG. 1, the repeater 3 is a device having a relay function for receiving the telegram 13 transmitted from the sensor 2 and transmitting the received telegram 13 to the receiver 4. In FIG. 1, the ceiling from the indoor on the first floor to the receiver 4 installed on the back of the ceiling on the second floor, and the outer wall from the outside to the receiver 4 become obstacles, both indoors and outdoors on the first floor. Since the radio wave output from the installed sensor 2 is difficult to reach the receiver 4 or does not reach the receiver 4, a mode in which the radio wave is installed in the back of the ceiling on the first floor and in an appropriate place outdoors is shown.

  FIG. 4 is a block diagram showing an electrical configuration of the repeater 3. As illustrated in FIG. 4, the repeater stores a wireless communication unit 14 that communicates a message between the sensor 2 and the receiver 4 and various types of information included in the message 13 received by the wireless communication unit 14. For example, a storage unit 15 and a control unit 16 including a microcomputer having a built-in ROM for storing a control program, a RAM for temporarily storing data, and the like are provided.

  In addition, the control unit 16 functionally stores the message 13 received by the wireless communication unit 14 in order to prevent interference between the storage unit 17 that stores sensor identification information (ID) and the other wireless communication system 1. Only when the ID included and the ID stored in the storage unit 15 are collated and the collation unit 18 determines whether or not they match, and the collation unit 18 determines that the two IDs match. A transmission control unit 19 that receives the received electronic message 13 and outputs an instruction to transmit to the receiver 4 to the wireless communication unit 14;

  Returning to FIG. 1, the receiver 4 receives a radio wave from the sensor 2 or the repeater 3, obtains information by amplifying and demodulating the radio wave, accumulates and analyzes the information, and executes various processes. Equipment. FIG. 5 is a block diagram showing an electrical configuration of the receiver 4. As shown in FIG. 5, the receiver 4 communicates the wireless communication unit 20 that performs communication of the electronic message 13 between the sensor 2 and the repeater 3, and various information included in the electronic message 13 received by the wireless communication unit 20. A storage unit 21 that stores data, and a control unit 22 that includes, for example, a ROM that stores a control program, a RAM that temporarily stores data, and the like are included.

  In addition, the control unit 22 functionally amplifies and demodulates the radio wave received by the wireless communication unit 20, analyzes information before and after, and acquires the transmission source of the telegram 13 and the detected content (detected value). And an instruction unit 24 that instructs the operation of each device (the lighting device 5, the air conditioning device, or the speaker 7) based on the result of analysis by the information analysis unit 23. For example, when the instruction unit 24 receives a detection signal indicating that the human body has been detected from the human body sensors 2a to 2c, the instruction unit 24 outputs an instruction to turn on the lighting device 5 connected to the receiver 4 through the communication line, and the smoke sensor When a detection signal indicating that smoke has been detected from 2g and 2h and a detection signal indicating that an abnormality has been detected from the security sensors 2d and 2e in a warning state, the speaker 7 connected to the receiver 4 via the communication line is connected to the speaker 7 An instruction to output an alarm sound is output.

  In the wireless communication system 1 having the above-described configuration, it should be noted that even when the transmission of the telegram 13 is simultaneously performed from each sensor, the transmission period of at least one telegram for each sensor is: It is set so that it does not overlap in time with the transmission period of messages transmitted from other sensors. Hereinafter, this content will be described in detail.

  FIG. 6 is a time chart showing the conventional problems in the transmission operation of the message by the sensor 2 and the reception operation of the repeater 3a, and FIG. 7 is the transmission portion and the relay of the message by the sensor 2, which is a characteristic part of this embodiment. 5 is a time chart showing the transmission / reception operation of the receiver and the receiver 4. Here, the human body sensors 2a and 2b are given as an example of a sensor that performs a telegram transmission operation, and the repeater 3a is given as an example of a repeater.

  As shown in FIG. 6, when the transmission time intervals of the sensors 2a and 2b are the same, when the sensors 2a and 2b start transmitting messages at substantially the same time, the message transmission periods of the sensors 2a and 2b are superimposed on all the messages. To do. As a result, the telegrams transmitted from the sensors 2a and 2b collide in the repeater 3a, and the telegrams are not received by the repeater 3a. 6 indicates a state in which a message transmitted from the sensor 2a and a message transmitted from the sensor 2b collide, and the message has not been received by the repeater 3a. The numbers “1” to “5” in the squares indicate the number of times of transmission operations (or the number of ordinary messages transmitted) among the repeated transmission operations of a series of messages.

  Therefore, in the present embodiment, the sensors 2a and 2b generate the time required for a series of repeated transmission operations (the last generation after the sensors 2a and 2b start transmitting a message triggered by the detection value exceeding the threshold value). The time until transmission of the message is completed (hereinafter referred to as repeated transmission time T) is variably configured. That is, since the number of transmissions in a series of repeated transmission operations remains constant, the sensors 2a and 2b are configured so that the transmission time interval is variable. Here, it is assumed that the transmission time interval of the sensor 2b is constant and the transmission time interval of the sensor 2a is changed so that the message transmitted by the sensor 2a does not collide with the message transmitted by the sensor 2b.

  At this time, the repetitive transmission time of the sensor 2b is time T1, the repetitive transmission time of the sensor 2a is time T2, and the message length (the time required from the start of transmission of one message by the sensors 2a and 2b to the completion of transmission) is t. When doing so, the sensor 2a sets the time T2 to satisfy the following expression (1).

T2 ≧ T1 + 2 × t (1)
From the time T2 set on the basis of the equation (1) and the number of transmissions k of the message in the repeated transmission operation of the sensor 2a, the message transmission time interval Δt by the sensor 2a is calculated using the following equation (2).

Δt = T2 / (k−1) (2)
When the transmission time interval Δt of the sensor 2a is calculated using the following expressions (1) and (2), at least one of the messages transmitted from the sensor 2a includes a message transmitted from the sensor 2b and a transmission period. It is possible to avoid overlapping. Hereinafter, this reason will be described. FIG. 8 is a diagram for explaining the reason.

  The expression (1) means that the repeated transmission time T2 of the sensor 2a and the repeated transmission time T1 of the sensor 2b have a time difference of two or more message lengths. Here, for simplification of description, if the time T2 is T2 = T1 + 2 × t, as shown in FIG. 8A, the start timing of the repetitive transmission operation of the message by the sensor 2a and the sensor 2b The transmission start timing H1 of the last message in a series of repeated transmission operations by the sensor 2a and the transmission completion timing of the last message in a series of repeated transmission operations by the sensor 2b The time difference with H2 is one message length, and the transmission period of the last message of the sensor 2a and the transmission period of the last message of the sensor 2b are not superimposed.

  Further, as shown in FIG. 8B, when the start timing of the repeated message transmission operation by the sensor 2a is earlier by one message length than the start timing of the repeated message transmission operation by the sensor 2b, that is, the sensor 2a. Even when the transmission completion timing of the first message in the series of repeated transmission operations by and the transmission start timing of the first message in the series of repeated transmission operations by the sensor 2b are substantially simultaneous (timing H3), the last message of the sensor 2a The transmission start timing is substantially the same as the transmission completion timing of the last message of the sensor 2b, and the transmission period of the last message of the sensor 2a and the transmission period of the last message of the sensor 2b do not overlap.

  Needless to say, when the start timing of the repetitive transmission operation of the message by the sensor 2a is delayed by one message length from the start timing of the repetitive transmission operation of the message by the sensor 2b, that is, the transmission start of the first message of the sensor 2a is started. When the timing and the transmission completion timing of the first message of the sensor 2b are substantially simultaneous, the transmission start timing of the last message of the sensor 2a is delayed by 2 × t from the transmission completion timing of the last message of the sensor 2b. The transmission period operation of the last message of the sensor 2a and the transmission period of the last message in a series of repeated transmission operations by the sensor 2b do not overlap.

  In this way, if the repeated transmission time T2 of the sensor 2a is set to have a time difference of two or more message lengths with respect to the repeated transmission time T1 of the sensor 2b, the transmission start timing of the message by the sensor 2a is No matter how fast or delayed the transmission start timing of the message by 2b is, at least a message whose transmission period does not necessarily overlap with the message transmission period by the sensor 2b is included in the message transmitted by the sensor 2a. It can be seen that one is generated. Therefore, the sensor 2a can transmit at least one electronic message to the repeater 3a without colliding with the electronic message transmitted from the sensor 2b.

  Furthermore, when two sensors are focused, the time difference between the repeated transmission times of each sensor may be set to two message lengths, so that there are three or more sensors that transmit messages to one repeater. Considering a combination of two arbitrarily selected sensors, it is preferable to set the time difference between the repeated transmission times of the sensors to be equal to or more than two message lengths in any combination. That is, assuming that the repetitive transmission time of one sensor is T, the repetitive transmission time of another sensor may be T + 2 × t, T + 4 × t, T + 6 × t,.

  By the way, in the description so far, the time T2 is set to T2 = T1 + 2 × t for simplification of the description. However, the time T2 is not limited to this value, as long as the expression (1) is satisfied. Good. Here, as a method of determining the time T2, for example, a plurality of arithmetic expressions satisfying the expression (1) such as T2 = T1 + 4 × t or T2 = T1 + 7 × t are stored in advance, and the sensor 2a collides with a message of another sensor. In such a case, a plurality of arithmetic expressions satisfying the expression (1) are stored in advance, and the sensor 2a transmits a message of another sensor. It is necessary to separately create a program for causing the sensor 2a to select an arithmetic expression that does not collide with the arithmetic expression from the plurality of arithmetic expressions, and this may lead to labor and cost increase.

Therefore, in the present embodiment, as the second point to be noted, the time T2 is determined by the following method. That is, in the present embodiment, the time T2 is determined using identification information (ID) assigned to the sensor 2a. Specifically, the number obtained by dividing the identification information (ID) assigned to the sensor 2a by a predetermined integer is multiplied by 2, and the time T2 is set to a coefficient n.
T2 = T1 + n × t (2)
Calculate based on

  When the time T2 is calculated based on the equation (2), the identification information is unique to each sensor. Therefore, the predetermined integer used when calculating the coefficient n is set to a relatively large value. By setting, it is possible to obtain a coefficient n specific to each sensor. Therefore, avoiding the repetition transmission time being the same as that of other sensors as much as possible, and separately creating the program as described above while making the repetition transmission time and the sensor correspond in a one-to-one relationship. It is possible to determine the transmission time interval Δt of the message.

  In this case, the following modifications may be employed instead of or in addition to the above embodiments.

  (1) As described above, the message is configured to include the preamble (PR), unique word (UW), identification information (ID), data (DATA), and error correction code (CRC) areas. As shown in FIG. 9, generally, in the message format used in an object-oriented sensor network such as the wireless communication system 1, the DATA area includes a Type area, a Property area, and a Data area.

  The Type area is an area in which information for distinguishing between an expression format of information written in a DATA area of a message in an object-oriented sensor network and an information expression format in a wireless device conventionally used is written. The Property area is an area in which information indicating the type of sensor is written. The Data area is an area in which information indicating the detection value of the sensor 2 is written. In such a message format, as the number of types of sensors 2 increases, the number of bits in the Property area becomes larger.

  Therefore, it is preferable to change the interpretation of the information written in the DATA area according to a part or all of the identification information (ID).

  That is, for example, the identification information of the human body sensor 2f has the first byte of 01h, the identification information of the smoke sensor 2g has the first byte of 02h, and the identification information of the security sensor 2d has the first byte of 03h. If the first byte of the identification information included in the received electronic message is 01h, the information written in the Data area is information indicating whether or not the human body sensor 2f has detected the human body. If the first byte is 02h, the information written in the Data area is interpreted as information indicating the smoke density of the smoke sensor 2g. If the first byte is 03h, the Data area The information written in is interpreted as information indicating whether the security sensor 2d is opened or closed.

  In this way, in order to change the information written in the Data area according to the identification information, the same detection value information (information written in the Data area) indicating the detection value is used between different types of sensors. be able to. For example, detection value information indicating that the human body sensor 2f has detected a human body and detection value information indicating that the security sensor 2d has detected the opening of the window can be made the same.

  As a result, the Type area and the Property area in the message are not necessary, and as shown in FIG. 10, the DATA area can be configured only by the Data area, and the message length can be shortened.

It is a figure which shows an example of the radio | wireless communications system which concerns on this invention. It is a block diagram which shows the electrical structure of each sensor. It is a figure which shows the structural example of a message | telegram. It is a block diagram which shows the electrical structure of a repeater. It is a block diagram which shows the electric constitution of a receiver. It is a time chart which shows the transmission operation | movement of the message | telegram by a sensor, and the transmission / reception operation | movement of a repeater and a receiver. The repeater 3a was able to receive the special message from the sensor, but the repeater 3b was not able to receive the special message from the repeater 3a due to the disturbance of the external noise, and as a result, the receiver could not receive the special message. It is the figure which showed the case. It is a figure which shows the state which the message | telegram from the repeater 3a and the message | telegram from the repeater 3b arrived at the receiver simultaneously. It is a figure which shows the message | telegram format used with an object-oriented sensor network. It is a figure which shows the modification of the message | telegram in the radio | wireless communications system of this invention. It is a figure which shows the typical structure of the conventional radio | wireless communications system. It is a figure which shows the communication aspect in the case of including a repeater. It is a time chart which shows operation | movement of the sensor in the case of including a repeater, a repeater, and a receiver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wireless communication system 2 Sensor 3, 3a, 3b Relay device 4 Receiver 5 Illumination equipment 7 Speaker 8 Detection part 9, 16, 22 Control part 10 Wireless transmission part 11 Transmission antenna 12 Battery 13 Message | telegram 14,20 Wireless communication part 15, 17, 21 Storage unit 18 Verification unit 19 Transmission control unit 23 Information analysis unit 24 Instruction unit

Claims (4)

A wireless transmitter that creates information and performs a transmission operation that repeats the information a predetermined number of times at predetermined intervals as a message,
When the time required for the wireless transmitter to transmit one message is a message length t and the time required for another wireless transmitter to perform the transmission operation is represented as time T1, the wireless transmitter performs the transmission operation. Time T2 required to do
T2 ≧ T1 + 2 × t
A wireless transmitter that sets the transmission interval of the message based on the time T2 and the predetermined number of times. When the identification information assigned to the wireless transmitter for individually identifying the wireless transmitter is obtained by multiplying the remainder obtained by dividing by an integer by 2 as a coefficient n, the time T2 is
T2 = T1 + n × t
If the predetermined number of times is k, the transmission interval Δt of the message is
Δt = T2 / (k−1)
The wireless transmitter according to claim 1, calculated by: A wireless communication system comprising: a wireless transmitter that creates information, performs a transmission operation that repeats the information a predetermined number of times as a message, and a wireless reception device that receives transmission information from the wireless transmitter; ,
The radio communication system according to claim 1, wherein the radio transmitter is a radio transmitter according to claim 1. The wireless transmitter includes a sensor unit that detects environmental information,
The message includes identification information for identifying the type of wireless transmitter and detection information indicating a detection value related to the environment information,
The detection information indicating the detection value of the first wireless transmitter and the detection information indicating the detection value of the second wireless transmitter of a different type from the first wireless transmitter are composed of the same signal,
The wireless reception device stores a correspondence relationship between the combination of the identification information and detection information and the detection content of the wireless transmitter in advance, and when receiving the message, based on the identification information and detection information included in the message, The wireless communication system according to claim 3, wherein the detected content of the wireless transmitter is interpreted.

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