System and method for self-calibrating, self-organizing and localizing sensors in wireless sensor networks

{
  "publication_number": "US2012036198A1",
  "country": "US",
  "kind": "A1",
  "title": "System and method for self-calibrating, self-organizing and localizing sensors in wireless sensor networks",
  "abstract": "A method of self-organizing sensor nodes in a wireless sensor network (WSN); a method of localizing mobile nodes in a WSN; and a method of self-calibrating a WSN are disclosed. The method of self-organizing sensor nodes in a WSN includes configuring sensor nodes to in turn broadcast consecutive messages at a plurality of pre-defined and incrementally increasing power levels; detecting receipt of the broadcasted messages at each of the sensor nodes and notifying a master node as to the identity of each sensor node receiving the broadcasted message and the power level at which it was received to define a detected neighbourhood for each sensor node; determining relative locations of sensor nodes with the detected neighbourhoods; and mapping relative locations of the sensor nodes by the master node based on results of the neighborhood detection and known locations of two anchor nodes.",
  "claims": [
    "1. A method of self-organizing sensor nodes in a wireless sensor network (WSN), the WSN comprising a plurality of sensor nodes in communication with a master node, the method comprising: distributing/installing the sensor nodes in an environment at predefined absolute locations, wherein two of the sensor nodes are anchor nodes of known ID and absolute locations; configuring each of the sensor nodes to in turn broadcast consecutive messages at a plurality of pre-defined and incrementally increasing power levels; detecting receipt of the broadcasted messages at each of the sensor nodes and notifying the master node as to the identity of each sensor node receiving the broadcasted message and the power level at which it was received to define a detected neighbourhood for each sensor node; determining relative locations of the sensor nodes with the detected neighbourhoods; and mapping relative locations of the sensor nodes by the master node based on results of the neighborhood detection and the known locations of the two anchor nodes. 2. A method of localizing mobile nodes in a wireless sensor network (WSN), the WSN comprising a plurality of sensor nodes connected to a master node, the method comprising: broadcasting a first identification message from a mobile node at a first predefined transmit power level; detecting receipt of the broadcasted message at each of the sensor nodes and sending a response message to the mobile node if the first identification message is received; estimating, based on a reception range of the first message, the location of the mobile node relative to the responding sensor node(s) if the first identification message is received, else broadcasting a second identification message from the mobile node at a plurality of increasing second predefined transmit power levels, the second predefined transmit power levels being higher than the first predefined transmit power level; detecting receipt of the second message at each of the sensor nodes and sending a response message to the mobile node as to the identity of each sensor node receiving the second message and the second power level at which it was received; and determining the location of the mobile node relative to the sensor nodes by triangulation. 3. The method of localizing a mobile node in a WSN according to claim 2, additionally comprising using an accelerometer and a compass integrated with the mobile node to supplement/enhance radio-based localization. 4. The method of localizing a mobile node in a WSN according to claim 2, additionally comprising: controlling the frequency of broadcasting the first and second identification messages by the mobile node based on the motion of the mobile node. 5. A method of self-calibrating a wireless sensor network (WSN), the WSN comprising a plurality of sensor nodes connected to a master node, the method comprising: transmitting wireless signals at a known power level between each pair of neighboring sensor nodes among the plurality of sensor nodes; measuring received signal strength at each of the neighboring sensor nodes; determining a transmission coefficient for each pair of neighboring sensor nodes; and determining a translation vector for each position between pairs of neighboring sensor nodes based on the corresponding transmission coefficients for the neighboring sensor nodes. 6. The method of self-calibrating a WSN according to claim 5, additionally comprising: receiving a localized position for a mobile node located between a pair of neighboring sensor nodes; and applying a corresponding translation vector to the localized position to determine a calibrated localization position for the mobile node. 7. The method of self-calibrating a WSN according to claim 5, additionally comprising repeating the transmitting, measuring and determining operations to account for at least one variation of wireless signal transmission in the WSN."
  ],
  "description_excerpt": "The present invention relates generally to the field of wireless networks, and more particularly, to the field of Wireless Sensor Networks (“WSN”).\n\nWireless sensor networks may typically involve hundreds or thousands of small, preferably inexpensive sensor devices or nodes that can remotely communicate with neighboring devices such as over a wireless communication link within a limited radio range. The devices typically include a sensing ability, computational ability, and bi-directional wireless communications ability, and may also include an integrated power supply. By relaying information to each other, sensors operate to transmit signals to a command post or central network sensor or gateway which may be located anywhere within the network.\n\nWireless sensors are used to detect any of a variety of parameters, including for example: environmental; motion or force; electromagnetic; and chemical or biological data. They are used in a wide variety of applications such as: agriculture; weather; aerospace; military; environment or industrial control and monitoring; wildlife monitoring; security monitoring; inventory control; and many others.\n\nIn order to make the use of the data collected by the sensors practical, it is desirable to know the location of each sensor in the network. Known sensor localization methods include use of the global navigation satellite systems (“GNSS”), triangulation-based multidimensional scaling, convex optimization, and semidefinite programming (“SDP”) relaxation, for example.",
  "cpc": [
    "H04B 17/27",
    "H04B 17/318",
    "H04L 2101/681",
    "H04W 52/322",
    "H04W 52/362",
    "H04W 52/50",
    "H04W 84/18"
  ],
  "ipc": [
    "G06F 15/177",
    "G06F 15/16",
    "G06F 15/173",
    "H04L 29/12",
    "H04W 52/50",
    "H04W 84/18"
  ],
  "inventors": [
    "Marcin MARZENCKI",
    "Bozena Kaminska"
  ],
  "filing_date": "2010-08-06",
  "publication_date": "2012-02-09",
  "priority_date": "2010-08-06",
  "application_number": "US-85242410-A",
  "family_id": "45556900",
  "cited_by_count": 161,
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