# US 2021/0242920 A1 · Method for waking from energy-efficient hibernation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242920 A1 - Document ID: US20210242920A1 - Status: Published application - Kind: A1 - Application number: 17/065,197 - Filed: 2020-10-07 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: Trakpoint Solutions, Inc. - Applicants: Trakpoint Solutions, Inc. - Inventors: Jon Siann; Christopher Williams - Web page: https://patentgrep.com/patent/US20210242920A1 ## CPC - H04B 7/0693: {switching off a diversity branch, e.g. to save power} - G06F 1/12: Synchronisation of different clock signals {provided by a plurality of clock generators} - G06F 1/3206: Monitoring of events, devices or parameters that trigger a change in power modality - G06F 1/3237: by disabling clock generation or distribution - G06F 1/325: {Power saving in peripheral device} - G06F 9/4418: {Suspend and resume; Hibernate and awake} - H04B 7/2609: {Arrangements for range control, e.g. by using remote antennas} - H04W 4/02: Services making use of location information - H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication - G06F 1/3231: Monitoring the presence, absence or movement of users - G06F 9/4401: Bootstrapping (security arrangements therefor G06F21/57) - Y02D 10/00: Energy efficient computing, e.g. low power processors, power management or thermal management - Y02D 30/70: in wireless communication networks - H04B: TRANSMISSION - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE ## Abstract The present invention is directed to energy-efficient hibernation in indoor wireless localization systems. A tag passively associates with a detection point (DP) and establishes a reveille time. The tag will awaken at the reveille time and send or receive a beacon to or from its associated DP. If the tag is receiving a beacon, it will awaken, receive, phase-lock its clock based on when the beacon was expected and when it was actually received, and return to hibernation. The DP transmits a scattershot of beacons, one for every tag in the system. If the tag is sending a beacon, it will awaken, send its beacon, and return to hibernation. The DP will receive the beacon and adjust its own clock based on the delay between when the beacon was expected and when it was actually received. The tag will broadcast its location to the DP on a set interval. ## Claims ### Claim 1 A method (100) of waking from energy-efficient hibernation to receive indoor localization beacons, the method comprising: a. passively associating (101), by a tag (1001), with a detection point (DP) of a plurality of DPs if the tag (1001) has moved to a new location, wherein associating comprises determining, by the tag (1001), a reveille time, wherein the reveille time is calculated in a cloud server, wherein the reveille time is equal to at least a concatenation or hash of a tag ID and a DP ID, a geographic number, a location ID of a DP (1002) modified by a location ID of a tag (1001), or a combination thereof; b. transmitting (102) at a first interval, by the DP (1002), a beacon for every possible address, wherein the beacon comprises the address; c. executing an awakening cycle (103) at a second interval, by the tag (1001), at the reveille time using a clock, wherein the awakening cycle further comprises: i. receiving (104), by the awakened tag (1001), the transmitted beacons, ii. confirming (105), by the awakened tag (1001), the address, iii. sleeping (108), by the awakened tag (1001); d. wherein communication between the tag (1001) and the DP (1002) comprises two-way authentication. ### Claim 2 (depends on 1) The method of claim 1, further comprising receiving, by each DP (1002) of the plurality of DPs, the updated location and filtering, by each DP (1002) of the plurality of DPs, noise associated with each transmission using a Kalman filter. ### Claim 3 (depends on 2) The method of claim 2 further comprising: a. determining, by each DP (1002) of the plurality of DPs, an Angle of Arrival of the Kalman-filtered transmission; and b. applying, by each DP (1002) of the plurality of DPs, MUltiple SIgnal Classification (MUSIC) to improve the accuracy of the determined Angle of Arrival. ### Claim 4 (depends on 1) The method of claim 1, wherein the clock is a resistive-capacitive circuit timing element (1004). ### Claim 5 (depends on 1) The method of claim 1, wherein the tag (1001) awakens from sleep by initiating a bare boot, wherein the bare boot comprises booting from a hibernation state directly to an awakened state. ### Claim 6 (depends on 5) The method of claim 5, wherein the bare boot comprises booting from hibernation without performing a system check, without reading all memory locations to ensure that memory has not been corrupted, and without checking the IO of peripherals. ### Claim 7 (canceled) ### Claim 8 (depends on 1) The method of claim 1, wherein the two-way authentication comprises comparing a first challenge encrypted by the tag (1001) and a second challenge encrypted by the DP (1002), wherein the first challenge is a prime integer equal to the second challenge. ### Claim 9 (depends on 1) The method of claim 1, wherein the awakening cycle (103) further comprises: a. determining (106), by the awakened tag (1001), a time difference between when the beacon was received and when the beacon was expected, and b. phase-locking (107), by the awakened tag (1001), the clock based on the time difference. ### Claim 10 A method (200) of waking from energy-efficient hibernation to transmit an indoor localization beacon, wherein the method comprises: a. passively associating (201), by a tag (1001), with a DP of a plurality of DPs if the tag (1001) has moved to a new location, wherein associating comprises determining, by the tag (1001), a reveille time, wherein the reveille time is calculated in a cloud server, wherein the reveille time is equal to at least a concatenation or hash of a tag ID and a DP ID, a geographic number, a location ID of a DP (1002) modified by a location ID of a tag (1001), or a combination thereof; b. executing an awakening cycle (202) at a second interval, by the tag (1001), at the reveille time using a first clock (1004), wherein the awakening cycle (202) further comprises: i. transmitting (203) at a first interval, by the awakened tag (1001), a beacon, wherein the beacon comprises an address, ii. receiving (204), by the DP (1002), the beacon, iii. confirming (205), by the DP (1002), the address, iv. sleeping (209), by the awakened tag (1001); c. wherein communication between the tag (1001) and the DP (1002) comprises two-way authentication. ### Claim 11 (depends on 10) The method of claim 10, further comprising receiving, by each DP (1002) of the plurality of DPs, the updated location and filtering, by each DP (1002) of the plurality of DPs, noise associated with each transmission using a Kalman filter. ### Claim 12 (depends on 11) The method of claim 11 further comprising: a. determining, by each DP (1002) of the plurality of DPs, an Angle of Arrival of the Kalman-filtered transmission; and b. applying, by each DP (1002) of the plurality of DPs, MUltiple SIgnal Classification (MUSIC) to improve the accuracy of the determined Angle of Arrival. ### Claim 13 (depends on 10) The method of claim 10, wherein the first clock (1004) is a resistive-capacitive circuit timing element (1004) and the second clock (1005) is a temperature-compensated crystal oscillator (TCXO) timing element (1005). ### Claim 14 (depends on 10) The method of claim 10, wherein the tag (1001) awakens from sleep by initiating a bare boot, wherein the bare boot comprises booting from a hibernation state directly to an awakened state. ### Claim 15 (depends on 14) The method of claim 14, wherein the bare boot comprises booting from booting from hibernation without performing a system check, without reading all memory locations to ensure that memory has not been corrupted, and without checking the IO of peripherals. ### Claim 16 (canceled) ### Claim 17 (depends on 10) The method of claim 10, wherein the awakening cycle (202) further comprises: a. updating (210), by the DP (1002), the location of the tag (1001), b. delaying (206), by the DP (1002), the timing of future transmission to the tag (1001) using a second clock (1005), wherein the delay is equal to a difference between when the beacon was received to when the beacon was expected. ### Claim 18 (depends on 10) The method of claim 10, wherein the two-way authentication comprises comparing a first challenge encrypted by the tag (1001) and a second challenge encrypted by the DP (1002), wherein the first challenge is a prime integer equal to the second challenge.