# US 2014/0192793 A1 · Systems and methods for hierarchical time source usage in near-me area network discovery and synchronization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192793 A1 - Document ID: US20140192793A1 - Status: Published application - Kind: A1 - Application number: 14/108,014 - Filed: 2013-12-16 - Published: 2014-07-10 - Earliest claimed: 2013-01-04 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Santosh Paul Abraham; George Cherian - Web page: https://patentgrep.com/patent/US20140192793A1 ## CPC - H04W 8/005: {Discovery of network devices, e.g. terminals} - H04B 7/2693: {Centralised synchronisation, i.e. using external universal time reference, e.g. by using a global positioning system [GPS] or by distributing time reference over the wireline network} - H04W 56/001: {Synchronization between nodes} - H04W 56/0015: {one node acting as a reference for the others} - H04W 56/002: {Mutual synchronization} - H04W 76/10: Connection setup - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract Methods, devices, and computer program products for hierarchical time source usage in near-me area network discovery and synchronization are described herein. In one aspect, a method for determining a discovery period using a hierarchy of external timing sources is provided. The method includes receiving an external timing signal from one or more external timing sources, and then using a hierarchy of external timing sources to determine which external timing source to use. The method further provides determining an offset from that external timing source, and using the external timing source and the offset to determine a discovery interval, in which to attempt to locate a near-me area network (NAN), such as a Social-WiFi network. ## Claims ### Claim 1 A wireless device in an ad-hoc wireless communication network comprising: a processor configured to determine a discovery interval, based at least in part on an offset and an external time based on a hierarchy of external timing sources; and a receiver configured to scan for messages from a wireless network during the discovery interval. ### Claim 2 (depends on 1) The wireless device of claim 1, wherein the offset is based, at least in part, on an external timing source used to determine the external time. ### Claim 3 (depends on 1) The wireless device of claim 1, wherein the hierarchy of external timing sources is ordered based, at least in part, on an accuracy or a granularity of an external timing source. ### Claim 4 (depends on 1) The wireless device of claim 1, wherein the hierarchy of external timing sources includes at least one of a time from a global positioning system source, a time from a cellular network, a time from an infrastructure access point, a time from a hierarchy of infrastructure access points. ### Claim 5 (depends on 4) The wireless device of claim 4 wherein the hierarchy of infrastructure access points is based, at least in part, on at least one of a wireless network name and a wireless network signal strength. ### Claim 6 (depends on 5) The wireless device of claim 5, wherein the hierarchy of infrastructure access points is based on a wireless network signal strength, such that infrastructure access points are ordered from strong to weak signal strengths, or near to infrastructure far access points. ### Claim 7 (depends on 1) The wireless device of claim 1, further comprising a sensor configured to detect when the wireless device is in motion, and wherein the processor is further configured to determine a discovery interval based, at least in part, on the motion of the wireless device. ### Claim 8 (depends on 7) The wireless device of claim 7, wherein the sensor comprises one or more of a GPS receiver and an accelerometer. ### Claim 9 (depends on 1) The wireless device of claim 1, further comprising a transmitter configured to, if no messages are received during the discovery interval, transmit discovery packets or synchronization messages during the discovery interval. ### Claim 10 (depends on 8) The wireless device of claim 8, wherein the discovery packets or synchronization messages include an indication of an external timing source used to determine the discovery interval. ### Claim 11 (depends on 1) The wireless device of claim 1, wherein the processor is configured to determine a plurality of periodically-recurring discovery intervals, and the receiver is configured to scan for messages during one or more of the plurality of periodically-recurring discovery intervals. ### Claim 12 A method for using a hierarchy of timing sources to determine a discovery interval, the method comprising: searching for external timing sources; if one or more external timing sources are found: ordering the one or more external timing sources based at least on a hierarchy; determining an offset; and calculating a discovery interval, based at least on the ordered external timing sources and the offset. ### Claim 13 (depends on 12) The method of claim 12, wherein determining the offset comprises determining the offset based, at least in part, on the external timing sources found and the hierarchy. ### Claim 14 (depends on 12) The method of claim 12, wherein the hierarchy includes an ordered list of external timing source, the order based, at least in part, on an accuracy or a granularity of an external timing source. ### Claim 15 (depends on 12) The method of claim 12, wherein the hierarchy includes at least one of a time from a global positioning system source, a time from a cellular network, a time from an infrastructure access point, and a time from a hierarchy of infrastructure access points. ### Claim 16 (depends on 15) The method of claim 15, wherein the hierarchy of infrastructure access points is based, at least in part, on at least one of a wireless network name and a wireless network signal strength. ### Claim 17 (depends on 16) The method of claim 16, wherein the hierarchy of infrastructure access points is based on a wireless network signal strength, such that infrastructure access points are ordered from strong to weak signal strengths, or near to infrastructure far access points. ### Claim 18 (depends on 12) The method of claim 12, further comprising detecting when a wireless device is in motion, and wherein searching for external timing sources comprises searching for external timing sources based at least in part on the motion of the wireless device. ### Claim 19 (depends on 12) The method of claim 12, further comprising: scanning for messages during the discovery interval; and if no messages are received during the discovery interval, transmitting discovery packets or synchronization messages during the discovery interval. ### Claim 20 (depends on 19) The method of claim 19, wherein the discovery packets or synchronization message include an indication of an external timing source used to calculate the discovery interval. ### Claim 21 (depends on 12) The method of claim 12, wherein calculating a discovery interval comprises calculating a plurality of periodically-recurring discovery intervals. ### Claim 22 An apparatus for wireless communications comprising: means for searching for external timing sources; if one or more external timing sources are found: means for ordering the one or more external timing sources based at least on a hierarchy; means for determining an offset; and means for calculating a discovery interval, based at least on the ordered external timing sources and the offset. ### Claim 23 (depends on 22) The apparatus of claim 22, wherein means for determining the offset comprises means for determining the offset based, at least in part, on the external timing sources found and the hierarchy. ### Claim 24 (depends on 22) The apparatus of claim 22, wherein the hierarchy includes an ordered list of external timing source, the order based, at least in part, on an accuracy or a granularity of an external timing source. ### Claim 25 (depends on 22) The apparatus of claim 22, wherein the hierarchy includes at least one of a time from a global positioning system source, a time from a cellular network, a time from an infrastructure access point, and a time from a hierarchy of infrastructure access points. ### Claim 26 (depends on 25) The apparatus of claim 25, wherein the hierarchy of infrastructure access points is based, at least in part, on at least one of a wireless network name and a wireless network signal strength. ### Claim 27 (depends on 26) The apparatus of claim 26, wherein the hierarchy of infrastructure access points is based on a wireless network signal strength, such that infrastructure access points are ordered from strong to weak signal strengths, or near to infrastructure far access points. ### Claim 28 (depends on 12) The apparatus of claim 12, further comprising means for detecting when a wireless device is in motion, and wherein means for searching for external timing sources comprises means for searching for external timing sources based at least in part on the motion of the wireless device. ### Claim 29 (depends on 12) The apparatus of claim 12, further comprising: means for scanning for messages during the discovery interval; and means for transmitting discovery packets or synchronization messages during the discovery interval if no messages are received during the discovery interval. ### Claim 30 (depends on 12) The apparatus of claim 12, wherein means for calculating a discovery interval comprises means for calculating a plurality of periodically-recurring discovery intervals.