# US 10,371,790 B2 · Calibration-free location determination using wireless communication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,790 B2 - Document ID: US10371790B2 - Status: Granted - Kind: B2 - Application number: 15/534,486 - Filed: 2014-12-12 - Published: 2017-11-23 - Granted: 2019-08-06 - Earliest claimed: 2014-12-12 - Assignees: ARRIS Enterprises LLC - Applicants: Ruckus Wireless, Inc. - Inventors: Yang Han - Web page: https://patentgrep.com/patent/US10371790B2 ## CPC - G01S 5/14: Determining absolute distances from a plurality of spaced points of known location - G01S 5/30: Determining absolute distances from a plurality of spaced points of known location - G01S 11/06: using intensity measurements - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract In order to accurately determine the location of an electronic device in an environment, a computer selects a set of received-signal-strength (RSS) values based on wireless communication between the electronic device and access points in sub-regions of the environment. This set includes a largest RSS value associated with a sub-region and at least two RSS values associated with neighboring sub-regions. Then, the computer calculates pairwise distance estimates of the location of the electronic device in the environment based on predefined locations of the access points associated with the set, one or more differences of pairs of RSS values in the set and a predetermined path-loss factor in the environment, where a given pair of RSS values includes the largest RSS value and one of the at least two RSS values. Furthermore, the computer determines the location of the electronic device in the environment based on the pairwise distance estimates. ## Claims ### Claim 1 A computer, comprising: one or more nodes; an interface circuit, coupled to the one or more nodes, configured to communicate with access points via a network; a processor coupled to the interface circuit; and memory, coupled to the processor, that stores program instructions, wherein, when executed by the processor, the program instructions cause the computer to perform one or more operations comprising: receiving, from the one or more nodes, received-signal-strength (RSS) values associated with the access points in sub-regions of an environment, wherein the RSS values characterize wireless communication between the access points and an electronic device in the environment; selecting a subset of the RSS values from a subset of the access points, wherein the subset of the RSS values comprises a largest RSS value associated with a sub-region and at least N RSS values associated with one or more access points in neighboring sub-regions, and wherein N is an integer; calculating pairwise distance estimates of a location of the electronic device in the environment based on predefined locations of the subset of the access points, one or more differences of pairs of RSS values in the subset of the RSS values and a predetermined path-loss factor in the environment, wherein a given pair of RSS values comprises a largest RSS value and one of the at least N RSS values; and determining the location of the electronic device in the environment based on the pairwise distance estimates. ### Claim 2 (depends on 1) The computer of claim 1, wherein each sub-region comprises one of the access points. ### Claim 3 (depends on 1) The computer of claim 1, wherein N is two. ### Claim 4 (depends on 1) The computer of claim 1, wherein the environment comprises a building; and wherein the selecting involves identifying access points that are located on a common floor in the building. ### Claim 5 (depends on 1) The computer of claim 1, wherein the sub-regions comprise Voronoi cells; and wherein a given access point is located at a center of a given Voronoi cell. ### Claim 6 (depends on 1) The computer of claim 1, wherein the one or more operations comprise sub-dividing the environment into the sub-regions. ### Claim 7 (depends on 1) The computer of claim 1, wherein determining the location of the electronic device comprises a regression technique and a set of equations that comprise the pairwise distance estimates, the predefined locations, parameters corresponding to the one or more differences of the pairs of RSS values and the predetermined path-loss factor. ### Claim 8 (depends on 1) The computer of claim 1, wherein the location of the electronic device is determined without calibration for one of: coverage of the access points in the environment, and access-point variability. ### Claim 9 (depends on 1) The computer of claim 1, wherein the wireless communication is associated with a common channel. ### Claim 10 (depends on 1) The computer of claim 1, wherein a difference between the largest RSS value and a given one of at least the N RSS values is less than a threshold value. ### Claim 11 (depends on 1) The computer of claim 1, wherein a computation complexity of the determination of the location of the electronic device is independent of a size of the environment and coverage of the access points in the environment. ### Claim 12 A non-transitory computer-readable storage medium for use in conjunction with a computer, the computer-readable storage medium storing program instructions, wherein, when executed by the computer, the program instructions cause the computer to determine a location of an electronic device in an environment by performing one or more operations comprising: receiving received-signal-strength (RSS) values associated with access points in sub-regions of an environment, wherein the RSS values characterize wireless communication between the access points and an electronic device in the environment; selecting a subset of the RSS values from a subset of the access points, wherein the subset of the RSS values comprises a largest RSS value associated with a sub-region and at least N RSS values associated with one or more access points in neighboring sub-regions, and wherein N is an integer; calculating pairwise distance estimates of a location of the electronic device in the environment based on predefined locations of the subset of the access points, one or more differences of pairs of RSS values in the subset of the RSS values and a predetermined path-loss factor in the environment, wherein a given pair of RSS values comprises a largest RSS value and one of the at least N RSS values; and determining the location of the electronic device in the environment based on the pairwise distance estimates. ### Claim 13 (depends on 12) The computer-readable storage medium of claim 12, wherein the environment comprises a building; and wherein the selecting involves identifying access points that are located on a common floor in the building. ### Claim 14 (depends on 12) The computer-readable storage medium of claim 12, wherein the one or more operations comprise sub-dividing the environment into the sub-regions. ### Claim 15 (depends on 12) The computer-readable storage medium of claim 12, wherein the location of the electronic device is determined without calibration for one of: coverage of the access points in the environment, and access-point variability. ### Claim 16 (depends on 12) The computer-readable storage medium of claim 12, wherein the wireless communication is associated with a common channel. ### Claim 17 (depends on 12) The computer-readable storage medium of claim 12, wherein a computation complexity of the determination of the location of the electronic device is independent of a size of the environment and coverage of the access points in the environment. ### Claim 18 A method for determining a location of an electronic device in an environment, wherein the method comprises: by a computer: receiving received-signal-strength (RSS) values associated with access points in sub-regions of an environment, wherein the RSS values characterize wireless communication between the access points and an electronic device in the environment; selecting a subset of the RSS values from a subset of the access points, wherein the subset of the RSS values comprises a largest RSS value associated with a sub-region and at least N RSS values associated with one or more access points in neighboring sub-regions, wherein N is an integer; calculating pairwise distance estimates of a location of the electronic device in the environment based on predefined locations of the subset of the access points, one or more differences of pairs of RSS values in the subset of the RSS values and a predetermined path-loss factor in the environment, wherein a given pair of RSS values comprises a largest RSS value and one of the at least N RSS values; and determining the location of the electronic device in the environment based on the pairwise distance estimates. ### Claim 19 (depends on 18) The method of claim 18, wherein the location of the electronic device is determined without calibration for one of: coverage of the access points in the environment, and access-point variability. ### Claim 20 (depends on 18) The method of claim 18, wherein a computation complexity of the determination of the location of the electronic device is independent of a size of the environment and coverage of the access points in the environment. ### Claim 21 A computer, comprising: one or more nodes; an interface circuit, coupled to the one or more nodes, configured to communicate with access points via a network; a processor coupled to the interface circuit; and memory, coupled to the processor, that stores program instructions, wherein, when executed by the processor, the program instructions cause the computer to perform one or more operations comprising: determining a location of an electronic device in an environment based on pairwise distance estimates that are calculated using predefined locations of access points in the environment, one or more differences of pairs of received-signal-strength (RSS) values from the access points and a predetermined path-loss factor in the environment, wherein the RSS values characterize wireless communication between the access points and the electronic device, and wherein the RSS values in a given pair of RSS values are associated with two different access points. ### Claim 22 (depends on 21) The computer of claim 21, wherein a computation complexity of the determination of the location of the electronic device is independent of a size of the environment and coverage of the access points in the environment.