JP4982191B2 - Sensor network - Google Patents

Description

  The present invention relates to a sensor network, and more particularly to a sensor network that transmits and receives data by wireless communication.

  A conventional sensor network includes a plurality of sensors and a sink node. The plurality of sensors include a sensor for detecting temperature, a sensor for detecting humidity, a sensor arranged on the first floor in the building, a sensor arranged on the second floor in the building, and the like. “Temperature”, “humidity”, “first floor”, “second floor”, and the like represent attributes of each sensor.

  When the user of the sensor network desires to know the temperature in the building, the query specifying the attribute “temperature” is input to the sink node, and the sink node receives the query including “temperature”. The received inquiry is broadcast to a plurality of sensors.

  Then, the sensor that detects the temperature receives a query including “temperature”, refers to the attribute (= “temperature”) of the received query, and transmits temperature data detected by itself to the sink node. Further, the sensor that detects other than the temperature receives an inquiry including “temperature”, and refers to the attribute (= “temperature”) of the received inquiry to determine that transmission of detection data is not requested. Then, the sensor that detects other than the temperature discards the inquiry.

  The sink node receives temperature data from a sensor that detects the temperature, and displays the received temperature data. Thereby, the user acquires desired temperature data.

As described above, in the conventional sensor network, inquiries to a plurality of sensors are transmitted by broadcast (Non-Patent Document 1).
Chalermek Intanagonwiwat, Ramesh Govindan, Deborah Estrin, John Heidemann, and Fabio Silva, "Directed Diffusion for Wireless Sensor Networking." ACM / IEEE Transactions on Networking, 11 (1), pp.2-16, February, 2002.

  However, in the conventional sensor network, since the inquiry is transmitted to a plurality of sensors by broadcasting, there is a problem that overhead when the inquiry is transmitted increases. As a result, the power consumption of each sensor that transfers a query also increases, and the query transfer efficiency becomes very low. This problem is particularly noticeable when the sensor network size is large.

  In addition, when an inquiry is transmitted by broadcast, each sensor corresponding to the inquiry transmits detection data to the sink node independently, which makes it difficult to efficiently collect data.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a sensor network capable of efficiently transmitting a query.

  Another object of the present invention is to provide a sensor network that can efficiently collect detection data.

  According to the present invention, the sensor network includes a plurality of sensors and a wireless device. Each of the plurality of sensors detects data. The wireless device identifies a part of the sensors that should transmit the detection data according to the sensor attributes, and sends a transmission request for requesting the transmission of the detection data to the specified part of the sensors. Send to some sensors via wireless communication.

  Preferably, the wireless device transmits a transmission request to some sensors by unicast and broadcast in a target area where some sensors exist.

  Preferably, the wireless device determines the target region based on the sensor identifier and the position information of the sensor corresponding to the identifier.

  Preferably, the wireless device determines a wireless communication path from itself to the target area, and unicasts a transmission request along the determined wireless communication path.

  Preferably, the wireless device determines a wireless communication path based on position information of a plurality of sensors so that the number of hops from itself to the target region is minimized.

  Preferably, the wireless device selects a first sensor existing at a position closest to itself from the sensors in the target region based on position information of some sensors, and performs wireless communication to the selected first sensor. Unicast the transmission request along the route. The first sensor broadcasts a transmission request received from the wireless device within the target area.

  Preferably, the wireless device selects a first sensor existing in a central portion in the target area based on position information of some sensors, and transmits the selected first sensor along the wireless communication path. Unicast the request. The first sensor broadcasts a transmission request received from the wireless device within the target area.

  Preferably, the wireless device performs unicast by including the wireless communication path in the transmission request. A sensor existing between the wireless device and some sensors relays the transmission request to the first sensor with reference to the wireless communication path included in the transmission request.

  Preferably, the transmission request includes identifiers of some sensors. Sensors existing between the wireless device and some sensors refer to the identifiers of some sensors included in the transmission request and relay the transmission request to the first sensor.

  Preferably, some sensors transmit their detection data to the first sensor. The first sensor collectively unicasts detection data received from some sensors to the wireless device along the wireless communication path.

  Preferably, the plurality of sensors includes m (m is a positive integer) sensors and n (n is a positive integer) sensors. The m sensors detect the first type of data. The n sensors detect a second type of data different from the first type.

  Preferably, the plurality of sensors includes m (m is a positive integer) sensors and n (n is a positive integer) sensors. The m sensors are arranged on the first floor in the building. The n sensors are arranged on a second floor different from the first floor.

  Preferably, the wireless device receives an instruction for designating some sensors from the outside, generates a transmission request based on the received instruction, and performs unicast.

  In the sensor network according to the present invention, the inquiry is transmitted by wireless communication to some of the plurality of sensors using the sensor attributes. As a result, wireless communication overhead is smaller than when an inquiry is transmitted to a plurality of sensors.

  Therefore, according to this invention, an inquiry can be transmitted efficiently.

  In the sensor network according to the present invention, the detection data of the sensors existing in the target area are collectively transmitted to the wireless device. As a result, the overhead of wireless communication becomes smaller than in the case where the sensor existing in the target area transmits detection data independently to the wireless device.

  Therefore, according to the present invention, detection data can be efficiently collected.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram of a sensor network according to an embodiment of the present invention. Referring to FIG. 1, a sensor network 100 according to an embodiment of the present invention includes a plurality of sensors 1 to 22 and a sink 30.

  The plurality of sensors 1 to 22 are disposed in a building, for example. The sensors 1 to 9 are, for example, humidity sensors, the sensors 10 to 12, 15, and 17 to 21 are, for example, illumination sensors, and the sensors 13, 14, 16, and 22 are, for example, temperature sensors. . Sensors 1 to 5 are arranged on the first floor in the building, for example, sensors 6 to 10 are arranged on the second floor in the building, for example, and sensors 11 to 15 are arranged on the third floor in the building, for example. Arranged, for example, the sensors 16 to 22 are arranged on the fourth floor in the building.

  The sensors 1 to 9 detect the humidity in the arranged building. The sensors 10 to 12, 15, and 17 to 21 detect the brightness in the arranged building. The sensors 13, 14, 16, and 22 detect the temperature in the arranged building.

  In the present invention, “humidity”, “brightness”, “temperature”, “first floor”, “second floor”, “third floor”, and “fourth floor” constitute sensor attributes.

  When each of the sensors 1 to 22 is the target of the inquiry QUERY, the sensors 1 to 22 receive the inquiry QUERY from the sink 30 by unicast and geocast by a method described later. Geocast refers to “broadcast in a target area where some sensors specified by sensor attributes exist”.

  When each of the sensors 1 to 22 receives the inquiry QUERY, it transmits detection data (humidity, brightness, and temperature) detected by itself to the sink 30 by a method described later.

  Further, each of the sensors 1 to 22 relays the inquiry QUERY when the sensors 1 to 22 are not subject to the inquiry QUERY.

  The sink 30 holds a table TBL including sensor attributes, sensor IDs corresponding to the sensor attributes, and sensor position information corresponding to the sensor IDs. Then, the sink 30 receives the instruction DIR from the user. This instruction DIR includes an attribute for designating a part of the plurality of sensors 1 to 22 for which the user desires to transmit detection data. For example, when the user desires to transmit temperature data, the instruction DIR includes an attribute “temperature”. User wants humidity data, brightness data, information on sensors placed on the first floor, information on sensors placed on the second floor, information on sensors placed on the third floor, and information on sensors placed on the fourth floor The same applies to the case.

  When the sink 30 receives the instruction DIR from the user, the sink 30 analyzes an attribute included in the received instruction DIR, and identifies some sensors that the user desires to transmit the detection data with reference to the table TBL. Then, the sink 30 determines a target area TREG to transmit the inquiry QUERY by a method to be described later based on the position information of the specified part of the sensors, and among the sensors in the determined target area TREG, The sensor NS closest to is detected. Thereafter, the sink 30 determines a wireless communication route RT for unicasting the inquiry QUERY from itself to the sensor NS by a method described later, the determined wireless communication route RT, an attribute instructed by the user, and a target area A query QUERY including TREG is generated. Then, the sink 30 unicasts the generated inquiry QUERY along the wireless communication path RT.

  Further, the sink 30 receives detection data of the sensor that is the target of the inquiry QUERY from the sensor NS.

  FIG. 2 is a schematic block diagram showing the configuration of the sensor 1 shown in FIG. Referring to FIG. 2, sensor 1 includes an antenna 101, a communication control unit 102, and a data detection unit 103. The antenna 101 transmits data from the communication control unit 102, and outputs data received from other sensors or sinks 30 and an inquiry QUERY to the communication control unit 102.

  The communication control unit 102 holds the position information of the sensor 1. When the communication control unit 102 receives the inquiry QUERY via the antenna 101, the communication control unit 102 determines whether the sensor 1 is a target of the inquiry QUERY based on the target region TREG included in the inquiry QUERY. More specifically, the communication control unit 102 determines whether the sensor 1 is included in the target region TREG based on the position information of the sensor 1 and the target region TREG, and the sensor 1 is included in the target region TREG. When included, it is determined that the sensor 1 is a target of the inquiry QUERY, and when the sensor 1 is not included in the target region TREG, it is determined that the sensor 1 is not a target of the inquiry QUERY.

  When the communication control unit 102 determines that the sensor 1 is the target of the inquiry QUERY, the communication control unit 102 extracts the detection data from the data detection unit 103, transmits the extracted detection data via the antenna 101, and transmits the inquiry QUERY to the antenna 101. Relay through.

  When the communication control unit 102 determines that the sensor 1 is not subject to the inquiry QUERY, the communication control unit 102 refers to the wireless communication path RT included in the inquiry QUERY and determines whether the sensor 1 should relay the inquiry QUERY. To do. More specifically, when the sensor 1 is included in the sensor on the wireless communication path RT, the communication control unit 102 determines that the sensor 1 should relay the inquiry QUERY, and the sensor 1 is on the wireless communication path RT. The sensor 1 determines that the inquiry QUERY does not have to be relayed.

  When the communication control unit 102 determines that the sensor 1 should relay the inquiry QUERY, the communication controller 102 relays the inquiry QUERY via the antenna 101 along the wireless communication path RT, and the sensor 1 does not relay the inquiry QUERY. When it is determined that it is acceptable, the inquiry QUERY is discarded.

  The data detection unit 103 detects the humidity in the building where the sensor 1 is arranged, and holds the detected humidity data.

  Each of the sensors 2 to 22 shown in FIG. 1 has the same configuration as that of the sensor 1 shown in FIG. In this case, the data detection unit 103 of the sensors 10 to 12, 15, and 17 to 21 detects the brightness in the building where the sensors 10 to 12, 15, and 17 to 21 are arranged, and uses the detected brightness data. Hold. The data detection unit 103 of the sensors 13, 14, 16, and 22 detects the temperature in the building where the sensors 13, 14, 16, and 22 are arranged, and holds the detected temperature data.

  FIG. 3 is a schematic block diagram showing the configuration of the sink 30 shown in FIG. Referring to FIG. 3, sink 30 includes an antenna 301, a communication unit 302, a control unit 303, a display unit 304, a reception unit 305, a route determination unit 306, and a data holding unit 307.

  The antenna 301 transmits the inquiry QUERY received from the communication unit 302 and outputs the detection data received from the sensors 1 to 22 to the communication unit 302.

  The communication unit 302 outputs the inquiry QUERY received from the control unit 303 to the antenna 301 and outputs the detection data received from the antenna 301 to the control unit 303.

  When the control unit 303 receives the instruction DIR from the reception unit 305, the control unit 303 analyzes the attribute included in the received instruction DIR and refers to the table TBL held in the data holding unit 307 so that the user transmits the detection data. Identify some desired sensors. Then, the control unit 303 determines a target area TREG to transmit the inquiry QUERY by a method described later based on the position information of the specified part of the sensors, and among the sensors in the determined target area TREG, The sensor NS closest to itself is detected. After that, the control unit 303 controls the route determination unit 306 to determine the wireless communication route RT for unicasting the inquiry QUERY from itself to the sensor NS, and receives the wireless communication route RT from the route determination unit 306. The query QUERY including the radio communication path RT, the attribute instructed by the user, and the target area TREG is generated. Then, the control unit 303 unicasts the generated inquiry QUERY along the wireless communication path RT via the communication unit 302 and the antenna 301.

  Further, when receiving the detection data from the communication unit 302, the control unit 303 stores the received detection data in the data holding unit 307 and displays the detection data on the display unit 304.

  The display unit 304 gives the detection data received from the control unit 303 to the user as visual information. The accepting unit 305 accepts an instruction DIR from the user, and outputs the accepted instruction DIR to the control unit 303.

  The route determination unit 306 determines a wireless communication route RT for unicasting the inquiry QUERY from the sink 30 to the sensor NS according to the control from the control unit 303 by a method described later, and the determined wireless communication route RT is determined by the control unit. To 303.

  The data holding unit 307 holds the table TBL and detection data.

  FIG. 4 is a schematic diagram illustrating a configuration of the inquiry QUERY. Referring to FIG. 4, the inquiry QUERY includes a header, an attribute, a target area TREG, and a radio communication path RT. The header consists of [destination / source]. The transmission destination is a transmission destination in each radio link when the inquiry QUERY is unicast along the radio communication path RT, and the transmission source is each transmission destination when the inquiry QUERY is unicast along the radio communication path RT. A transmission source in a wireless link.

  For example, if the query QUERY is unicast along a path consisting of sink 30 -sensor 1 -sensor 2 -sensor 3 -sensor 4, in the first radio link, the source is sink 30 and the destination is Sensor 1. In the second wireless link, the transmission source is the sensor 1 and the transmission destination is the sensor 2. Thereafter, similarly, the transmission source and the transmission destination are determined in the third wireless link and the fourth wireless link. As described above, the transmission destination and the transmission source are changed every time the inquiry QUERY is relayed.

  When the inquiry QUERY is broadcast (= geocast) in the target area TREG, the header is composed of a broadcast address.

  FIG. 5 is a diagram showing the configuration of the table TBL held by the data holding unit 307 shown in FIG. Referring to FIG. 5, table TBL includes attributes, IDs, and position information. The attribute, ID, and position information are associated with each other.

  The attribute consists of a sensor attribute. The ID is composed of an ID of a sensor corresponding to each attribute. The position information includes sensor position information corresponding to each attribute.

  More specifically, the attribute includes humidity, brightness, temperature, first floor, second floor, third floor, and fourth floor. The sensor IDs corresponding to the humidity attribute are ID1 to ID9, and the sensor IDs corresponding to the brightness attribute are ID10 to ID12, ID15, and ID17 to ID21. The IDs of the sensors corresponding to the temperature attribute are ID13, ID14, ID16, and ID22, and the IDs of the sensors corresponding to the attributes on the first floor are ID1 to ID5. Furthermore, the IDs of the sensors corresponding to the attributes of the second floor are ID6 to ID10, the IDs of the sensors corresponding to the attributes of the third floor are ID11 to ID15, and the IDs of the sensors corresponding to the attributes of the fourth floor are ID16 to ID22.

  Further, the sensor position information corresponding to the humidity attribute is [x1, y1] to [x9, y9], and the sensor IDs corresponding to the brightness attribute are [x10, y10] to [x12, y12]. ], [X15, y15], [x17, y17] to [x21, y21]. The sensor ID corresponding to the temperature attribute is [x13, y13], [x14, y14], [x16, y16], [x22, y22], and the sensor ID corresponding to the attribute on the first floor is [X1, y1] to [x5, y5]. Furthermore, the sensor IDs corresponding to the second floor attributes are [x6, y6] to [x10, y10], and the sensor IDs corresponding to the third floor attributes are [x11, y11] to [x15, y15]. The sensor IDs corresponding to the attributes of the fourth floor are [x16, y16] to [x22, y22].

  The sink 30 creates and holds a table TBL shown in FIG. 5 in advance. That is, the sink 30 holds the position information of the sensors 1 to 22 in advance.

  A method for determining the target region TREG for transmitting the inquiry QUERY will be described. FIG. 6 is a first diagram for explaining a method of determining the target region TREG. FIG. 7 is a second diagram for explaining a method of determining the target region TREG.

  Referring to FIG. 6, when control unit 303 of sink 30 receives instruction DIR including an attribute consisting of temperature from reception unit 305, it refers to the attribute (= temperature) of instruction DIR and the attribute is “temperature”. Detect that there is. Then, the control unit 303 reads the table TBL from the data holding unit 307, refers to the read table TBL, and ID13, ID14, ID16, ID22 of the sensor corresponding to the attribute of “temperature” and the position information [x13, y13], [x14, y14], [x16, y16], [x22, y22] are detected.

  As a result, the control unit 303 detects that the sensors to which the inquiry QUERY is transmitted are the sensors 13, 14, 16, and 22.

  Then, the control unit 303 sets the minimum X coordinate Xmin and the maximum X coordinate Xmax among the detected position information [x13, y13], [x14, y14], [x16, y16], [x22, y22]. The minimum Y coordinate Ymin and the maximum Y coordinate Ymax are detected, and an area within the coordinates [Xmin, Ymin] to [Xmax, Ymax] is detected as the target area TREG (see FIG. 7). That is, the control unit 303 sets a region surrounded by a straight line L1 composed of x = Xmin, a straight line L2 composed of x = Xmax, a straight line L3 composed of y = Ymin, and a straight line L4 composed of y = Ymax. Detect as TREG.

  Then, the control unit 303 stores the position information [x0, y0] of the sink 30 held by itself and the position information [x13, y13], [x14, y14], [x16] of the sensors 13, 14, 16, and 22 , Y16], [x22, y22], the sensor 13 present at the closest position to the sink 30 is selected from the sensors 13, 14, 16, and 22 included in the target region TREG.

  When the control unit 303 detects the sensor 13 present at the position closest to the sink 30, the control unit 303 outputs the ID 13 of the detected sensor 13 to the route determination unit 306, and sets the wireless communication route RT from the sink 30 to the sensor 13. The route determination unit 306 is controlled to determine.

  FIG. 8 is a diagram for explaining a method of determining the wireless communication route RT. When the path determination unit 306 receives the ID 13 of the sensor 13 from the control unit 303, the route determination unit 306 reads the table TBL from the data holding unit 307, and wireless communication from the sink 30 to the sensor 13 based on the read table TBL and ID 13. A route RT is determined. More specifically, the route determination unit 306 detects the position information [x1, y1] to [x22, y22] of the sensors 1 to 22 described in the table TBL, and the detected position information [x1, y1]. Based on ~ [x22, y22], the positions of the sensors 1 to 22 are grasped, and the number of hops from the sink 30 to the sensor 13 is minimized based on the positions of the sensors 1 to 22. -A route including the sensor 11-the sensor 12-the sensor 13 is determined as the wireless communication route RT. Then, the route determination unit 306 outputs the determined wireless communication route RT to the control unit 303.

  FIG. 9 is a diagram for explaining a method of transmitting an inquiry QUERY to the target region TREG. When the control unit 303 of the sink 30 receives the wireless communication route RT from the route determination unit 306, the header including [Sensor 10 / Sink 30], the attribute including “temperature”, and the target region TREG (= [Xmin, Ymin ] To [Xmax, Ymax]) and a wireless communication path RT (= sink 30-sensor 10-sensor 11-sensor 12-sensor 13) QUERY = [sensor 10 / sink 30 / temperature / [Xmin, Ymin] ] To [Xmax, Ymax] / sink 30-sensor 10-sensor 11-sensor 12-sensor 13], and the generated query QUERY = [sensor 10 / sink 30 / temperature / [Xmin, Ymin] to [Xmax]. , Ymax] / Sink 30-Sensor 10-Sensor 11-Sensor 12-Sensor 3] via the communication unit 302 and the antenna 301 to be transmitted to the sensor 10 by unicast.

  The communication control unit 102 of the sensor 10 sends an inquiry QUERY = [sensor 10 / sink 30 / temperature / [Xmin, Ymin] to [Xmax, Ymax] / sink 30-sensor 10-sensor 11-sensor 12-sensor 13 from the sink 30. ] And the sensor 10 is not included in the target area TREG by the above-described method with reference to the target area TREG (= [Xmin, Ymin] to [Xmax, Ymax]) of the received inquiry QUERY. judge. Then, the communication control unit 102 of the sensor 10 should relay the inquiry QUERY to the sensor 11 with reference to the wireless communication path RT (= sink 30 -sensor 10 -sensor 11 -sensor 12 -sensor 13) of the inquiry QUERY. QUERY = [Sensor 11 / Sensor 10 / Temperature / [Xmin, Ymin] to [Xmax, Ymax] / Sink 30-Sensor 10-Sensor 11-Sensor 12-sensor 13] and the generated query QUERY = [sensor 11 / sensor 10 / temperature / [Xmin, Ymin] to [Xmax, Ymax] / sink 30-sensor 10-sensor 11-sensor 12-sensor 13 ] To the sensor 11 via the antenna 101 That.

  The communication control unit 102 of the sensors 11 and 12 relays the inquiry QUERY to the sensors 12 and 13 by the same operation as the communication control unit 102 of the sensor 10.

  As a result, the inquiry QUERY is transmitted from the sink 30 to the sensor 13 by unicast.

  The communication control unit 102 of the sensor 13 sends an inquiry QUERY = [sensor 13 / sensor 12 / temperature / [Xmin, Ymin] to [Xmax, Ymax] / sink 30-sensor 10-sensor 11-sensor 12-sensor 13 from the sensor 12. ] And the received inquiry QUERY = [sensor 13 / sensor 12 / temperature / [Xmin, Ymin] to [Xmax, Ymax] / sink 30-sensor 10-sensor 11-sensor 12-sensor 13] Referring to TREG (= [Xmin, Ymin] to [Xmax, Ymax]), the sensor 13 is a sensor included in the target region TREG, and a final destination sensor that transmits a query QUERY by unicast Is detected.

  Then, the communication control unit 102 of the sensor 13 broadcasts (= geocasts) the received inquiry QUERY within the target area TREG. Then, the communication control units 102 of the sensors 14 to 16 and 22 in the target area TREG also broadcast the inquiry QUERY in the target area TREG.

  Thereby, the communication control unit 102 of the sensors 13, 14, 16, and 22 existing in the target area TREG receives the inquiry QUERY = [broadcast address / temperature / [Xmin, Ymin] to [Xmax, Ymax]].

  Then, the communication control unit 102 of the sensors 13, 14, 16, and 22 refers to the attribute (= temperature) of the inquiry QUERY to confirm that transmission of detection data of the sensors 13, 14, 16, and 22 is requested. Then, temperature data T13, T14, T16, and T22 are read from the data detection unit 103, respectively.

  The communication control unit 102 of the sensor 15 also receives the inquiry QUERY = [broadcast address / temperature / [Xmin, Ymin] to [Xmax, Ymax]], but the attribute of the sensor 15 is “brightness”, and the inquiry Since it is different from the attribute (= temperature) of QUERY, the communication control unit 102 of the sensor 15 discards the inquiry QUERY without reading the detection data from the data detection unit 103.

  FIG. 10 is a diagram for explaining a method in which the sensor in the target area TREG transmits detection data to the sink 30.

  Referring to FIG. 10, among the sensors 13, 14, 16, and 22 that exist in the target region TREG, the communication control units 102 of the sensors 14, 16, and 22 other than the sensor 13 that is located closest to the sink 30 are The temperatures T14, T16, and T22 read from the data detection unit 103 are transmitted to the sensor 13 as detection data. In this case, the communication control unit 102 of the sensors 14 and 16 transmits the temperatures T14 and T16 directly to the sensor 13, respectively, and the communication control unit 102 of the sensor 22 transmits the temperature T22 to the sensor 13 via the sensor 15. .

  The communication control unit 102 of the sensor 13 receives the temperatures T14, T16, and T22 transmitted from the sensors 14, 16, and 22, the received temperatures T14, T16, and T22, and the temperature T13 detected by the sensor 13 and Are collectively created as detection data = [T13, T14, T16, T22], and the created detection data = [T13, T14, T16, T22] is transmitted to the sink 30 by unicast along the wireless communication path RT. . In this case, the sensors 12, 11, and 10 relay detection data = [T13, T14, T16, T22].

  Then, the control unit 303 of the sink 30 receives the detection data = [T13, T14, T16, T22] via the antenna 301 and the communication unit 302, and the received detection data = [T13, T14, T16, T22]. ] Is stored in the data holding unit 307, and detection data = [T13, T14, T16, T22] is output to the display unit 304. Then, the display unit 304 of the sink 30 gives the detection data = [T13, T14, T16, T22] to the user as visual information. Thereby, the user can acquire desired temperature data.

  FIG. 11 is a diagram for explaining another method for transmitting the inquiry QUERY to the target region TREG. Referring to FIG. 11, when the control unit 303 of the sink 30 determines the target area TREG to transmit the inquiry QUERY by the above-described method, the transmission destination when the inquiry QUERY is transmitted by unicast is set in the target area TREG. It is determined that the sensor 15 exists in the center.

  When the control unit 303 determines the transmission destination (= sensor 15) by the unicast of the inquiry QUERY, the control unit 303 outputs the ID 15 of the sensor 15 to the route determination unit 306. When receiving the ID 15 of the sensor 15, the route determination unit 306 reads the table TBL from the data holding unit 307, refers to the read table TBL, and unicasts the inquiry QUERY from the sink 30 to the sensor 15 by the method described above. The wireless communication path RT ′ (= sink 30-sensor 10-sensor 11-sensor 12-sensor 15) for transmission is determined, and the determined wireless communication path RT ′ is output to the control unit 303.

  Then, the control unit 303 of the sink 30 creates an inquiry QUERY including the wireless communication path RT ′ by the above-described method, and transmits the created inquiry QUERY to the sensor 15 by unicast along the wireless communication path RT ′. . In this case, the communication control unit 102 of the sensors 10, 11, 12 relays the inquiry QUERY to the sensors 11, 12, 15, respectively. As a result, the inquiry QUERY is transmitted to the sensor 15 by unicast.

  Then, the communication control unit 102 of the sensor 15 makes an inquiry QUERY = [sensor 15 / sensor 12 / temperature / [Xmin, Ymin] to [Xmax, Ymax] / sink 30-sensor 10-sensor 11-sensor 12-sensor 15]. And the received query QUERY = [sensor 15 / sensor 12 / temperature / [Xmin, Ymin] to [Xmax, Ymax] / sink 30-sensor 10-sensor 11-sensor 12-sensor 15] target area TREG Referring to (= [Xmin, Ymin] to [Xmax, Ymax]), the sensor 15 is a sensor included in the target region TREG, and is a final transmission destination sensor that transmits an inquiry QUERY by unicast. Detect something.

  Then, the communication control unit 102 of the sensor 15 broadcasts (= geocasts) the received inquiry QUERY within the target area TREG. Then, the communication control unit 102 of the sensors 13, 14, 16, and 22 in the target area TREG also broadcasts the inquiry QUERY in the target area TREG.

  Thereby, the communication control unit 102 of the sensors 13, 14, 16, and 22 existing in the target area TREG receives the inquiry QUERY = [broadcast address / temperature / [Xmin, Ymin] to [Xmax, Ymax]].

  Then, the communication control unit 102 of the sensors 13, 14, 16, and 22 refers to the attribute (= temperature) of the inquiry QUERY to confirm that transmission of detection data of the sensors 13, 14, 16, and 22 is requested. Then, temperature data T13, T14, T16, and T22 are read from the data detection unit 103, respectively.

  FIG. 12 is a diagram for explaining another method in which the sensor in the target region TREG transmits detection data to the sink 30.

  Referring to FIG. 12, the communication control unit 102 of the sensors 13, 14, 16, and 22 existing in the target region TREG uses the temperatures T <b> 13, T <b> 14, T <b> 16, T <b> 22 read from the data detection unit 103 as detection data. 15 to send.

  The communication control unit 102 of the sensor 15 receives the temperatures T13, T14, T16, and T22 transmitted from the sensors 13, 14, 16, and 22, and collectively detects the received temperatures T13, T14, T16, and T22. Data = [T13, T14, T16, T22] is created, and the created detection data = [T13, T14, T16, T22] is transmitted to the sink 30 by unicast along the wireless communication path RT ′. In this case, the sensors 12, 11, and 10 relay detection data = [T13, T14, T16, T22].

  Then, the control unit 303 of the sink 30 receives the detection data = [T13, T14, T16, T22] via the antenna 301 and the communication unit 302, and the received detection data = [T13, T14, T16, T22]. ] Is stored in the data holding unit 307, and detection data = [T13, T14, T16, T22] is output to the display unit 304. Then, the display unit 304 of the sink 30 gives the detection data = [T13, T14, T16, T22] to the user as visual information. Thereby, the user can acquire desired temperature data.

  As described above, in the present invention, the inquiry QUERY is transmitted to the sensors 13, 14, 16, and 22 that the user desires to transmit the detection data by unicast and broadcast (= geocast) in the target region TREG. Is done.

  Therefore, according to the present invention, the overhead when transmitting the inquiry QUERY can be reduced as compared with the case where the inquiry QUERY is broadcast to the sensors 1 to 22, and the inquiry QUERY can be transmitted efficiently.

  In the present invention, among the sensors 13, 14, 16, and 22 that the user desires to transmit the detection data, the sensor 13 closest to the sink 30 or the sensor 15 arranged in the center of the target area TREG receives the detection data. Collectively transmit to the sink 30.

  Therefore, according to the present invention, compared with the case where the sensors 13, 14, 16, and 22 transmit the detection data to the sink 30 independently, the overhead when transmitting the detection data can be reduced, and the detection data can be efficiently synced. 30.

  In the above description, the case where the inquiry QUERY including the attribute including “temperature” is transmitted has been described. However, the attributes are “humidity”, “brightness”, “first floor”, “second floor”, “third floor”, and “ Even in the case of “4th floor”, the target area TREG is determined according to the same operation as described above, and is present in the center of the target area TREG or the sensor or target area TREG that is closest to the sink 30. A wireless communication path to the sensor is determined, and an inquiry QUERY is transmitted to the target sensor by unicast along the determined wireless communication path and broadcast (= geocast) in the target area TREG. Then, detection data such as humidity is collected by one sensor and transmitted to the sink 30.

  In the above description, the case where there is one attribute has been described. However, when the attribute is two or more, the target region TREG is determined according to the same operation as described above, and the target region TREG is The wireless communication path to the sensor closest to the sink 30 or the sensor existing in the center of the target area TREG is determined, and the inquiry QUERY is unicast along the determined wireless communication path and within the target area TREG. It is transmitted to the target sensor by broadcast (= geocast). Then, two or more detection data such as humidity are collected by one sensor and transmitted to the sink 30.

  Furthermore, in the above description, the attribute is composed of “temperature”, “humidity”, “brightness”, “first floor”, “second floor”, “third floor”, and “fourth floor”. However, the attribute is not limited to this, and any attribute may be used as long as it can identify the sensor, such as the type of sensor, the position of the sensor, the sensitivity of the sensor, and the environment in which the sensor is used.

  Furthermore, in the above description, the sink 30 has been described as holding the position information of the sensors 1 to 22 in advance. However, in the present invention, the present invention is not limited to this, and each of the sensors 1 to 22 is a GPS (Global Positioning). System) may be mounted, the position of itself may be detected by GPS, and the position information of the detected position may be transmitted to the sink 30.

  Further, in the above description, the inquiry QUERY has been described as including the target area TREG. However, in the present invention, the query QUERY is not limited to this, and the ID of the sensor existing in the target area TREG is replaced with the target area TREG. May be included. In this case, the sensor that relays the inquiry QUERY by unicast compares the ID of the sensor included in the inquiry QUERY with its own ID, detects that the inquiry QUERY is not addressed to itself, and relays the inquiry QUERY.

  Furthermore, in the above description, the target region TREG has been described as a quadrangle. However, in the present invention, the present invention is not limited to this, and the target region TREG is between coordinates [Xmin, Ymin] and coordinates [Xmax, Ymax]. It may consist of a circle whose distance is the diameter, or it may consist of other shapes.

  Further, in the above, the inquiry QUERY is transmitted by unicast to the sensor located in the position closest to the sink 30 among the sensors existing in the target area TREG or the sensor arranged in the center of the target area TREG. As described above, in the present invention, the inquiry QUERY is preferably transmitted by unicast to a sensor that is closest to the sink 30 among the sensors that are present in the target region TREG. This is because the overhead of wireless communication can be reduced and the inquiry QUERY can be transmitted more efficiently when the inquiry QUERY is transmitted to the sensor located closest to the sink 30 among the sensors existing in the target region TREG. .

  Further, in the above description, the sensor network 100 that transmits the inquiry QUERY to the sensors 13, 14, 16, and 22 in the target region TREG and transmits the detection data of the sensors 13, 14, 16, and 22 to the sink 30 has been described. The sensor network according to the present invention only needs to include a plurality of sensors each detecting data, and a sink 30 that transmits an inquiry QUERY to some of the plurality of sensors by wireless communication. This is because by transmitting the inquiry QUERY to some sensors, the overhead of wireless communication can be made smaller than when the inquiry QUERY is transmitted to all sensors, and the inquiry QUERY can be transmitted efficiently.

  Furthermore, the sensor network according to the present invention transmits an inquiry QUERY to the sensors 1 to 22 by broadcasting, and the sensor 13 or 15 collects the detection data of the sensors 13, 14, 16, and 22 existing in the target region TREG together with the sink 30. Anything can be used. By transmitting the detection data of the sensors 13, 14, 16, and 22 existing in the target region TREG together to the sink 30, overhead when the sink 30 collects the detection data can be reduced, and the detection data can be efficiently used. This is because it can be collected.

  Further, in the present invention, the inquiry QUERY specifies a part of the sensors 13, 14, 16, and 22 to which the detection data should be transmitted according to the sensor attribute, and specifies the sensor A “transmission request” for requesting transmission of detection data (= temperature data) to some of the sensors 13, 14, 16, and 22 is configured.

  Further, the sensors 13, 14, 16, and 22 constitute “a part of sensors”, and the sink 30 constitutes a “wireless device”.

  Further, the sensor 13 constitutes a “first sensor”, and the sensors 1 to 9 constitute “m (m is a positive integer) number of sensors” and the sensors 10 to 12, 15, 17 to 21 or The sensors 13, 14, 16, and 22 constitute “n (n is a positive integer) number of sensors”, and the sensors 1 to 5 constitute “m (m is a positive integer) number of sensors”. Any of the sensors 6 to 10, the sensors 11 to 15, and the sensors 16 to 22 constitutes “n (n is a positive integer) number of sensors”.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a sensor network that can efficiently transmit a query. The present invention is also applied to a sensor network that can efficiently collect detection data.

It is the schematic of the sensor network by embodiment of this invention. It is a schematic block diagram which shows the structure of the sensor shown in FIG. It is a schematic block diagram which shows the structure of the sink shown in FIG. It is the schematic which shows the structure of an inquiry. It is a figure which shows the structure of the table which the data holding part shown in FIG. 4 hold | maintains. It is a 1st figure for demonstrating the determination method of an object area | region. It is a 2nd figure for demonstrating the determination method of an object area | region. It is a figure for demonstrating the method to determine a radio | wireless communication path. It is a figure for demonstrating the method to transmit an inquiry to an object area | region. It is a figure for demonstrating the method in which the sensor in an object area | region transmits detection data to a sink. It is a figure for demonstrating the other method of transmitting an inquiry to an object area | region. It is a figure for demonstrating the other method in which the sensor in an object area | region transmits detection data to a sink.

Explanation of symbols

  1 to 22 sensor, 30 sinks, 100 sensor network, 101, 301 antenna, 102 communication control unit, 103 data detection unit, 302 communication unit, 303 control unit, 304 display unit, 305 reception unit, 306 route determination unit, 307 data Holding part.

Claims (12)

A plurality of sensors each detecting data;
Transmission for requesting transmission of the detection data from the plurality of specified sensors by specifying a part of the plurality of sensors to which the detection data is to be transmitted according to the attribute of the sensor A wireless device for transmitting a request to the some sensors by wireless communication ;
The wireless device transmits the transmission request by unicast to a target region where the some of the plurality of sensors exist,
The sensor network in which the some of the plurality of sensors broadcast the transmission request in the target area . The sensor network according to claim 1 , wherein the wireless device determines the target area based on an identifier of the sensor and position information of a sensor corresponding to the identifier. The sensor network according to claim 1 or 2 , wherein the wireless device determines a wireless communication path from itself to the target area, and unicasts the transmission request along the determined wireless communication path. 4. The sensor network according to claim 3 , wherein the wireless device determines the wireless communication path based on positional information of the plurality of sensors so that the number of hops from itself to the target region is minimized. The wireless device selects a first sensor present at a position closest to itself from the sensors in the target region based on position information of the some of the plurality of sensors, and moves to the selected first sensor. Unicast the transmission request along the wireless communication path;
The sensor network according to claim 4 , wherein the first sensor broadcasts a transmission request received from the wireless device in the target area. The wireless device selects a first sensor existing in a central portion in the target area based on position information of the some of the plurality of sensors, and connects the selected first sensor to the wireless communication path. Unicast the transmission request along
The sensor network according to claim 4 , wherein the first sensor broadcasts a transmission request received from the wireless device in the target area. The wireless device unicasts the wireless communication path in the transmission request,
Sensor existing between from the wireless device to a plurality of sensors of said portion relays the reference above transmission request of the wireless communication route included in the transmission request to the first sensor, according to claim 5 Or the sensor network of Claim 6 . The transmission request includes identifiers of the some of the plurality of sensors,
Sensors existing between the wireless device and the some of the plurality of sensors relay the transmission request to the first sensor with reference to identifiers of the some of the plurality of sensors included in the transmission request. The sensor network according to any one of claims 5 to 7 . The some sensors send their detection data to the first sensor,
The first sensor according to any one of claims 4 to 8 , wherein the first sensor collectively unicasts detection data received from the plurality of sensors to the wireless device along the wireless communication path. The sensor network described. The plurality of sensors are:
M sensors (m is a positive integer) for detecting the first type of data;
Wherein n for detecting the data of the first type is different from the second type (n is a positive integer) and a number of sensors, sensor network according to any one of claims 1 to 9. The plurality of sensors are:
M sensors (m is a positive integer) arranged on the first floor in the building;
The first floor and the different second is an n arranged on the floor (n is a positive integer) and a number of sensors, sensor network according to any one of claims 1 to 10. The wireless device receives an instruction specifying a plurality of sensors of the part from the outside, and unicast to generate the transmission request based on the received instruction, any of claims 1 to 11 1 The sensor network described in the section.

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