# US 2018/0324592 A1 · Secure Connection Release and Network Redirection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324592 A1 - Document ID: US20180324592A1 - Status: Published application - Kind: A1 - Application number: 16/033,282 - Filed: 2018-07-12 - Published: 2018-11-08 - Earliest claimed: 2016-08-12 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Venkateswara Rao Manepalli; Srinivasan Nimmala; Farouk Belghoul - Web page: https://patentgrep.com/patent/US20180324592A1 ## CPC - H04W 12/08: Access security - H04W 12/06: Authentication - H04W 12/30: Security of mobile devices; Security of mobile applications - H04W 36/0061: {of neighbour cell information} - H04W 48/02: Access restriction performed under specific conditions - H04W 48/16: Discovering, processing access restriction or access information - H04W 76/10: Connection setup - H04W 76/18: Management of setup rejection or failure - H04W 76/30: Connection release - H04W 12/33: using wearable devices, e.g. using a smartwatch or smart-glasses - H04W 36/38: by fixed network equipment - H04W 88/06: adapted for operation in multiple networks {or having at least two operational modes}, e.g. multi-mode terminals - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract This disclosure relates to techniques for securely performing connection release and network redirection in a wireless communication system. A wireless device may establish a radio resource control (RRC) connection with a first cell. The wireless device may receive a RRC connection release message from the first cell. The RRC connection release message may include an indication to redirect the wireless device to a second cell. The RRC connection with the first cell may be released. It may be determined whether security has been established with the first cell when the indication to redirect the wireless device to the second cell is received. A new serving cell may be selected based at least in part on whether security has been established with the first cell when the indication to redirect the wireless device to the second cell is received. ## Claims ### Claim 1 An apparatus, comprising: a processing element configured to cause a wireless device to: establish a radio resource control (RRC) connection with a first cell; receive an RRC connection release message from the first cell, wherein the RRC connection release message comprises an indication to redirect the wireless device to a second cell; release the RRC connection with the first cell; determine whether security has been established with the first cell when the indication to redirect the wireless device to the second cell is received; determine whether a stored configuration indicates to ignore indications to redirect to an insecure cell that are received with an RRC connection release message prior to security establishment; in response to determining: the security has not been established with the first cell when the indication to redirect the wireless device to the second cell is received, and the stored configuration indicates to ignore indications to redirect to an insecure cell that are received with an RRC connection release message prior to security establishment, ignore the redirection indication and select a new serving cell. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the second cell operates according to a specific radio access technology (RAT) that is less secure than the RAT of the first cell. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the second cell is selected when security has been established with the first cell when the indication to redirect the wireless device to the second cell is received. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein selecting the new serving cell is further based at least in part on a radio access technology of the second cell. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein selecting the new serving cell is further based at least in part on security and authentication procedures associated with the second cell. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the processing element is further configured to cause the wireless device to: declare radio link failure for the first cell when security has not been established with the serving cell when the indication to redirect the wireless device to the second cell is received; and perform a tracking area update with the new serving cell after selecting the new serving cell based at least in part on declaring radio link failure for the first cell. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the processing element is further configured to cause the wireless device to: bar the first cell when the security has not been established with the first cell when the indication to redirect the wireless device to the second cell is received. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the processing element is further configured to cause the wireless device to: bar the second cell when the security has not been established with the first cell when the indication to redirect the wireless device to the second cell is received. ### Claim 9 A method, comprising: by a wireless device: establishing a radio resource control (RRC) connection with a first cell; receiving a RRC connection reject message from the first cell, wherein the RRC connection reject message comprises an indication to redirect the wireless device to a second cell; releasing the RRC connection with the first cell; determining whether security has been established with the first cell when the indication to redirect the wireless device to the second cell is received; determining whether a stored configuration indicates to ignore indications to redirect to cells of the specific RAT that are received with a RRC connection reject message prior security establishment; in response to determining: the security has not been established with the first cell when the indication to redirect the wireless device to the second cell is received, and the stored configuration indicates to ignore indications to redirect to cells of the specific radio access technology that are received with an RRC connection reject message prior security establishment, ignoring the redirection indication and selecting a new serving cell. ### Claim 10 (depends on 9) The method of claim 9, wherein the second cell operates according to a specific radio access technology (RAT) that is less secure than the RAT of the first cell. ### Claim 11 (depends on 10) The method of claim 10, wherein the wireless device is configured to select the second cell as the new serving cell when the second cell operates according to a second RAT different from the specific RAT. ### Claim 12 (depends on 10) The method of claim 10, wherein the specific RAT comprises GSM, wherein the second RAT comprises LTE or UMTS. ### Claim 13 (depends on 9) The method of claim 9, wherein selecting the new serving cell is further based at least in part on security and authentication procedures associated with the second cell. ### Claim 14 (depends on 9) The method of claim 9, wherein the method further comprises: barring the first cell or a frequency on which the first cell is deployed when the second cell operates according to a specific radio access technology. ### Claim 15 (depends on 9) The method of claim 9, wherein the method further comprises: barring the second cell or a frequency on which the second cell is deployed when the second cell operates according to a specific radio access technology. ### Claim 16 A non-transitory, computer accessible memory medium storing program instructions executable by a processor of a wireless device to cause the wireless device to: establish a radio resource control (RRC) connection with a first cell; receive an RRC connection release message from the first cell, wherein the RRC connection release message comprises an indication to redirect the wireless device to a second cell; release the RRC connection with the first cell; determine whether security has been established with the first cell when the indication to redirect the wireless device to the second cell is received; determine whether a stored configuration indicates to ignore indications to redirect to an insecure cell that are received with an RRC connection release message prior to security establishment; in response to determining: the security has not been established with the first cell when the indication to redirect the wireless device to the second cell is received, and the stored configuration indicates to ignore indications to redirect to an insecure cell that are received with an RRC connection release message prior to security establishment, ignore the redirection indication and select a new serving cell. ### Claim 17 (depends on 16) The non-transitory computer accessible memory medium of claim 16, wherein the second cell operates according to a specific radio access technology (RAT) that is less secure than a RAT of the first cell. ### Claim 18 (depends on 16) The non-transitory computer accessible memory medium of claim 16, wherein the second cell is selected when security has been established with the first cell when the indication to redirect the wireless device to the second cell is received. ### Claim 19 (depends on 16) The non-transitory computer accessible memory medium of claim 16, wherein selecting the new serving cell is further based at least in part on a RAT of the second cell. ### Claim 20 (depends on 16) The non-transitory computer accessible memory medium of claim 16, wherein the program instructions are further executable to cause the wireless device to: declare radio link failure for the first cell when security has not been established with the serving cell when the indication to redirect the wireless device to the second cell is received; and perform a tracking area update with the new serving cell after selecting the new serving cell based at least in part on declaring radio link failure for the first cell.