# US 10,321,373 B1 · Control of handover based on past duration of control-plane signaling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,321,373 B1 - Document ID: US10321373B1 - Status: Granted - Kind: B1 - Application number: 15/223,197 - Filed: 2016-07-29 - Granted: 2019-06-11 - Earliest claimed: 2016-07-29 - Assignees: Sprint Spectrum L.P. - Applicants: Sprint Spectrum L.P. - Inventors: Ahmad N. Saleh; Deveshkumar N. Rai; Jasinder P. Singh - Web page: https://patentgrep.com/patent/US10321373B1 ## CPC - H04W 36/08: Reselecting an access point - H04W 36/0016: {Hand-off preparation specially adapted for end-to-end data sessions} - H04W 36/00835: {Determination of neighbour cell lists} - H04W 36/008375: {based on historical data} - H04W 36/0072: {of resource information of target access point} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Disclosed is a method and system for selecting a target base station for handover of a wireless communication device, where the selecting is based at least in part on a consideration of the target base station's typical control-plane signaling latency in a core network, and particularly based on a comparison of control-plane signaling duration of multiple candidate target base stations. For instance, where all of the base stations are configured to engage in a particular control-plane signaling transaction from time to time, at issue could be which of the candidate target base stations typically engages in that control-plane signaling transaction the quickest. ## Claims ### Claim 1 A method for controlling handover of a wireless communication device (WCD) served by a source base station, the method comprising: selecting by the source base station a target base station to which to hand over the WCD, wherein selecting the target base station is based on determining that, among a plurality of candidate target base stations that are each configured to engage in a particular control-plane signaling transaction on a core access network, the selected target base station's engaging in the particular control-plane signaling transaction on the core access network has historically been quickest compared with each other candidate target base station's engaging in the particular control-plane signaling transaction on the core access network, wherein determining that the selected target base station's engaging in the particular control-plane signaling transaction on the core access network has historically been quickest compared with each other candidate target base station's engaging in the particular control-plane signaling transaction on the core access network is based on an average of durations of past instances of the selected target base station's engaging in the particular control-plane signaling transaction; and based on the selecting, invoking by the source base station handover of the WCD to the selected target base station. ### Claim 2 (depends on 1) The method of claim 1, wherein selecting the target base station based on determining that the target base station's engaging in the particular control-plane signaling transaction on the core access network has historically been quickest compared with each other candidate target base station's engaging in the particular control-plane signaling transaction on the core access network comprises: receiving from each candidate target base station a measure of how long it has taken the candidate target base station to engage in the particular control-plane transaction, and comparing the received measures, to determine which candidate target base station's engaging in the particular control-plane signaling transaction on the core access network has historically been quickest compared with each other candidate target base station's engaging in the particular control-plane signaling transaction on the core access network. ### Claim 3 (depends on 1) The method of claim 1, wherein the particular control-plane signaling transaction is an attach process, from an attach-request message to an attach-accept message. ### Claim 4 (depends on 1) The method of claim 1, wherein the particular control-plane signaling transaction is control-plane signaling ranging from transmitting an attach request to receiving an authentication request. ### Claim 5 (depends on 1) The method of claim 1, wherein invoking handover of the WCD to the selected target base station comprises: engaging in handover signaling with the selected target base station to prepare the handover; and directing the WCD to hand over to the selected target base station. ### Claim 6 A method for controlling handover of a wireless communication device (WCD) served by a source base station, the method comprising: identifying a plurality of candidate target base stations for the WCD, wherein each candidate target base station provides air interface coverage in which to serve WCDs and is configured to engage in a control-plane signaling transaction on a core access network; respectively for each identified candidate target base station, determining by the source base station, based on past instances of the candidate target base station engaging in the control-plane signaling transaction on the core access network, a representative duration of the candidate target base station engaging in the control-plane signaling transaction, wherein the representative duration is based on an average of the past instances of the candidate target base station engaging in the control-plane signaling transaction; selecting by the source base station one of the identified candidate target base stations as a target base station for handover of the WCD, wherein the selecting is based on the selected candidate target base station having, among the plurality of candidate target base stations, a lowest determined representative duration of the candidate target base station engaging in the control-plane signaling transaction; and invoking by the source base station handover of the WCD from the source base station to the target base station. ### Claim 7 (depends on 6) The method of claim 6, wherein identifying the plurality of candidate target base stations for the WCD comprises determining that the WCD is within threshold strong coverage of each candidate target base station of the plurality. ### Claim 8 (depends on 7) The method of claim 7, wherein determining that the WCD is within threshold strong coverage of each candidate target base station of the plurality is based on one or more measurement reports from the WCD. ### Claim 9 (depends on 6) The method of claim 6, wherein determining respectively for each identified candidate target base station the representative duration of the identified candidate target base station engaging in control-plane signaling transaction comprises receiving from the identified candidate target base station a report of the representative duration of the candidate target base station engaging in the control-plane signaling transaction. ### Claim 10 (depends on 6) The method of claim 6, wherein the control-plane signaling transaction is an attach process, and wherein the representative duration of engaging in the attach process is a duration from an attach-request message to an attach-accept message. ### Claim 11 (depends on 6) The method of claim 6, wherein the control-plane signaling transaction is control-plane signaling ranging from transmitting an attach request to receiving an authentication request. ### Claim 12 (depends on 6) The method of claim 6, wherein selecting one of the identified candidate target base stations as the target base station for handover of the WCD based on the selected candidate target base station having, among the plurality of candidate target base stations, a lowest determined representative duration of engaging in the control-plane signaling transaction comprises: comparing the determined representative durations of the identified candidate target base stations, to determine which of the identified candidate target base stations has the lowest determined representative duration; and selecting the determined candidate target base station as the target base station for handover of the WCD. ### Claim 13 (depends on 6) The method of claim 6, wherein invoking handover of the WCD from the source base station to the target base station comprises: engaging in handover signaling with the target base station to prepare the handover; and directing the WCD to hand over to the target base station. ### Claim 14 A base station comprising: an antenna structure for engaging in air interface communication with wireless communication devices (WCDs); a backhaul communication interface for engaging in backhaul communication on a core access network; a controller configured to control handover of a WCD served by the base station, wherein the controller is configured to (i) select a target base station to which to hand over the WCD, wherein selecting of the target base station is based on the controller determining that, among a plurality of candidate target base stations that are each configured to engage in a particular control-plane signaling transaction on the core access network, the selected target base station's engaging in the particular control-plane signaling transaction on the core access network has historically been quickest compared with each other candidate target base station's engaging in the particular control-plane signaling transaction on the core access network, wherein determining that the selected target base station's engaging in the particular control-plane signaling transaction on the core access network has historically been quickest compared with each other candidate target base station's engaging in the particular control-plane signaling transaction on the core access network is based on an average of durations of past instances of the selected target base station's engaging in the particular control-plane signaling transaction, and (ii) invoke handover of the WCD to the selected target base station. ### Claim 15 (depends on 14) The base station of claim 14, wherein selecting of the target base station based on the controller determining that the target base station's engaging in the particular control-plane signaling transaction on the core access network has historically been quickest compared with each other candidate target base station's engaging in the particular control-plane signaling transaction on the core access network comprises: receiving via the backhaul communication interface from each candidate target base station a measure of how long it has taken the candidate target base station to engage in the particular control-plane transaction, and comparing the received measures, to determine which candidate target base station's engaging in the particular control-plane signaling transaction on the core access network has historically been quickest compared with each other candidate target base station's engaging in the particular control-plane signaling transaction on the core access network. ### Claim 16 (depends on 14) The base station of claim 14, wherein the particular control-plane signaling transaction is an attach process, from an attach-request message to an attach-accept message. ### Claim 17 (depends on 14) The base station of claim 14, wherein invoking handover of the WCD to the selected target base station comprises: engaging in handover signaling with the selected target base station to prepare the handover; and directing the WCD to hand over to the selected target base station.