{
  "patent_number": "US 6590928",
  "country": "US",
  "title": "How Bluetooth Creates Wireless Networks with Unique Addresses",
  "original_title": "Frequency hopping piconets in an uncoordinated wireless multi-user system",
  "summary": "This 2003 patent describes how Bluetooth devices use a master device's address and clock to create a unique, hopping radio channel for communication and build a network map.",
  "what_it_does": "This patent details a system for wireless devices, like early Bluetooth gadgets, to form a network. A 'master' device sends its unique address and a clock signal to 'slave' devices. This information dictates how the radio channel will 'hop' between frequencies, making it unique and secure for that specific network. The master then asks the slaves for their own addresses and who they can talk to (topology information). It uses this data to build a 'configuration tree,' which is like a map of the network, helping it figure out the best way to send messages between devices. For example, a master phone could use this to connect to headphones and a keyboard, understanding how they relate to each other in the network.",
  "what_it_does_not_cover": [
    "Wireless networks where the hopping pattern isn't based on a master device's unique address.",
    "Systems that don't use a clock signal from the master to control the timing of the frequency hops.",
    "Methods for building a network map that don't involve collecting addresses and 'first order' connection lists from slave devices.",
    "Forming a configuration tree that doesn't follow specific rules about how 'rings' of connections can include or exclude devices.",
    "Directly controlling a device's power settings or data transmission rates."
  ],
  "filed": "1997-09-17",
  "granted": "2003-07-08",
  "expires": "2017-09-17",
  "status": "expired",
  "holder": "Telefonaktiebolaget LM Ericsson AB",
  "holder_url": "https://patentbrief.org/company/telefonaktiebolaget-lm-ericsson-ab",
  "inventors": [
    {
      "name": "Jacobus Cornelis Haartsen",
      "url": "https://patentbrief.org/inventor/jacobus-cornelis-haartsen"
    }
  ],
  "times_cited": 131,
  "tags": [
    "consumer_electronics",
    "telecommunications",
    "software"
  ],
  "abstract": "A wireless network includes master and slave units. The master sends a master address and clock to the slaves. Communication is by means of a virtual frequency hopping channel whose hopping sequence is a function of the master address, and whose phase is a function of the master clock. Transmitted inquiry messages solicit slave address and topology information from the slaves, which may be used to generate a configuration tree for determining a route for a connection between the master and slave units. Slave address and topology information may include an own address from each of the slave units and only first order address lists from each of the slave units. Generating the configuration tree involves generating a hierarchy of connectivity rings from the first order address lists. Each connectivity ring may be generated in accordance with a rule that a higher-numbered connectivity ring cannot include nodes representing units that are already represented by a node in a lower-numbered connectivity ring. Alternatively, each connectivity ring may be generated by considering a present numbered connectivity ring having parent nodes, and including in a next higher-numbered connectivity ring those nodes representing all children of the parent nodes such that no descendant of a parent can represent the same unit as the parent; no descendant of a parent's child can represent the same unit as any of the parent's children; and no child of any parent can have the same name as any other child of said any parent.",
  "url": "https://patentbrief.org/patent/us/6590928/bluetooth-frequency-hopping",
  "markdown_url": "https://patentbrief.org/patent/us/6590928/bluetooth-frequency-hopping/md",
  "google_patents_url": "https://patents.google.com/patent/US6590928",
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}