# US 2014/0192669 A1 · Filtering of wi-fi physical layer measurements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192669 A1 - Document ID: US20140192669A1 - Status: Published application - Kind: A1 - Application number: 14/152,739 - Filed: 2014-01-10 - Published: 2014-07-10 - Earliest claimed: 2013-01-10 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Xiaowen Wang; Vinay R. Majjigi; Syed A. Mujtaba; Christopher J. Hansen - Web page: https://patentgrep.com/patent/US20140192669A1 ## CPC - H04B 17/318: Received signal strength - H04B 17/26: using historical data, averaging values or statistics - H04W 48/16: Discovering, processing access restriction or access information - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A station (STA) can receive messages (e.g., beacon frames) at a regular interval, and perform measurements on the received messages. The STA maintains a running average of recent measurement values, and updates the running average after each new measurement interval. At some measurement opportunities, the expected messages cannot be received by the STA, and so the STA cannot perform a measurement; when this occurs, the STA can choose substitute values to use for the missed measurements when next calculating the running average. As one example, the STA can substitute the value for a previously-performed measurement for the missed measurements. As another example, the STA can substitute a predetermined low value for the missed measurements. Based on the value of the running average at a given point in time, the STA can take actions such as initiating a roaming scan or switching to a different wireless interface. ## Claims ### Claim 1 A method for use in an electronic device, the method comprising: obtaining a set of one or more measurement values based on signals received by the electronic device during an averaging time window, each measurement value corresponding to a particular measurement interval in the averaging time window; obtaining a set of one or more substitute values for one or more measurement intervals in the averaging time window when signals are not successfully received during corresponding measurement intervals; determining an average measurement value for the averaging time window based on the set of one or more measurement values and on the set of one or more substitute values; and performing a corrective action when the average measurement value satisfies a performance criterion. ### Claim 2 (depends on 1) The method of claim 1, wherein obtaining the set of substitute values for one or more measurement intervals in the averaging time window comprises one or more of: using the measurement value from a prior measurement interval in which a signal was successfully received; using the measurement value from a most recent measurement interval in which the signal was successfully received; and using a predetermined value. ### Claim 3 (depends on 1) The method of claim 1, wherein determining the average measurement value for the averaging time window comprises using a filter to combine the set of one or more measurement values and the set of one or more substitute values. ### Claim 4 (depends on 3) The method of claim 3, wherein the filter is a finite impulse response (FIR) filter that weights each measurement value and each substitute value by a weighting factor and combines weighted measurement values and weighted substitute values. ### Claim 5 (depends on 3) The method of claim 3, wherein the filter is an infinite impulse response (IIR) filter that combines a most recent measurement value or substitute value for a most recent measurement time interval using a weighting factor of alpha with a most recent average measurement value using a weighting factor of (one minus alpha). ### Claim 6 (depends on 2) The method of claim 2, wherein the predetermined value comprises a value corresponding to a physical layer measurement for which data packets are not decodable or for which an out of synchronization condition can occur. ### Claim 7 (depends on 1) The method of claim 1, wherein the electronic device comprises a wireless station (STA) that operates in accordance with a wireless local area networking communication protocol. ### Claim 8 (depends on 7) The method of claim 7, wherein the signal comprises a beacon transmitted at regular time intervals by an access point (AP). ### Claim 9 (depends on 7) The method of claim 7, wherein the wireless local area networking communication protocol is a Wi-Fi communication protocol. ### Claim 10 (depends on 1) The method of claim 1, wherein obtaining the set of substitute values for one or more measurement intervals in the averaging time window comprises: using the measurement value from a most recent measurement interval in which the signal was successfully received for measurement intervals that occur within a predetermined number of measurement intervals of the most recent measurement interval in which a signal was successfully received; and using a predetermined value for measurement intervals that occur beyond the predetermined number of measurement intervals of the most recent measurement interval in which the signal was successfully received. ### Claim 11 (depends on 1) The method of claim 1, wherein the average measurement value satisfies the performance criterion when the average measurement value provides an indication of a radio link failure condition for a wireless connection between the electronic device and a second electronic device. ### Claim 12 (depends on 9) The method of claim 9, wherein performing the corrective action comprises one or more of: performing a roaming scan and switching between different wireless interfaces of the electronic device. ### Claim 13 An electronic device comprising processing circuitry configured to cause the electronic device to at least: obtain a set of one or more measurement values based on signals received by the electronic device during an averaging time window, each measurement value in the set of measurement values corresponding to a particular measurement interval in the averaging time window; obtain a set of one or more substitute values for one or more measurement intervals in the averaging time window when signals are not successfully received during corresponding measurement intervals; and determine an average measurement value for the averaging time window based on the set of one or more measurement values and on the set of one or more substitute values. ### Claim 14 (depends on 13) The electronic device of claim 13, wherein the processing circuitry is further configured to cause the electronic device to perform a corrective action when the average measurement value satisfies a performance criterion. ### Claim 15 (depends on 13) The electronic device of claim 13, wherein the processing circuitry comprises at least a wireless module and an application processor. ### Claim 16 (depends on 13) The electronic device of claim 13, wherein the electronic device comprises a wireless station (STA) operates in accordance with a Wi-Fi wireless communication protocol, and wherein the signals comprise beacons transmitted by a wireless access point (AP). ### Claim 17 (depends on 13) The electronic device of claim 13, wherein the processing circuitry is configured to cause the electronic device to determine the average measurement value for the averaging time window by using a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter that weights and combines the one or more measurement values and the one or more substitute values. ### Claim 18 (depends on 13) The electronic device of claim 13, wherein the processing circuitry is configured to cause the electronic device to obtain the set of one or more substitute values for one or more measurement intervals in the averaging time window by one or more of: using the measurement value from a prior measurement interval in which a signal was successfully received; using the measurement value from a most recent measurement interval in which the signal was successfully received; and using a predetermined value. ### Claim 19 (depends on 13) The electronic device of claim 13, wherein the processing circuitry is configured to cause the electronic device to obtain the set of one or more substitute values for one or more measurement intervals in the averaging time window by: using the measurement value from a most recent measurement interval in which the signal was successfully received for measurement intervals that occur within a predetermined number of measurement intervals of the most recent measurement interval in which a signal was successfully received; and using a predetermined value for measurement intervals that occur beyond the predetermined number of measurement intervals of the most recent measurement interval in which the signal was successfully received. ### Claim 20 A non-transitory computer readable medium having computer program code stored thereon, the computer program code, when executed by one or more processors on an electronic device, causes the electronic device to perform a method comprising: obtaining a set of one or more measurement values based on signals received by the electronic device during an averaging time window, each measurement value corresponding to a particular measurement interval in the averaging time window; obtaining a set of one or more substitute values for one or more measurement intervals in the averaging time window when signals are not successfully received during corresponding measurement intervals; determining an average measurement value for the averaging time window based on the set of one or more measurement values and on the set of one or more substitute values; and performing a corrective action when the average measurement value satisfies a performance criterion.