# US 8,542,835 B2 · Method and system for mobile communications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,835 B2 - Document ID: US8542835B2 - Status: Granted - Kind: B2 - Application number: 12/366,384 - Filed: 2009-02-05 - Published: 2009-06-18 - Granted: 2013-09-24 - Earliest claimed: 1997-04-24 - Assignees: Ntt Docomo, Inc. - Applicants: Motoshi Tamura; Mutsumaru Miki; Akiko Okamoto; Kenya Kusunose; Akihiro Uchikoshi; Daisuke Igarashi; Katsuhiko Yamagata; Takaaki Sato; Junichiro Hagiwara; Yasuyuki Watanabe; Takuya Hamajima; Masafumi Hata; Nobutaka Ishikawa; Yoshiyuki Yasuda; Kazufumi Yunoki; Nobuhide Uchiyama - Inventors: Motoshi Tamura; Mutsumaru Miki; Akiko Okamoto; Kenya Kusunose; Akihiro Uchikoshi; Daisuke Igarashi; Katsuhiko Yamagata; Takaaki Sato; Junichiro Hagiwara; Yasuyuki Watanabe; Takuya Hamajima; Masafumi Hata; Nobutaka Ishikawa; Yoshiyuki Yasuda; Kazufumi Yunoki; Nobuhide Uchiyama - Web page: https://patentgrep.com/patent/US8542835B2 ## CPC - H04B 7/022: Site diversity; Macro-diversity (using two or more spaced independent antennas H04B7/04) - H04W 12/03: Protecting confidentiality, e.g. by encryption - H04W 36/302: {due to low signal strength} - H04W 52/04: Transmission power control [TPC] - H04W 84/042: {Public Land Mobile systems, e.g. cellular systems} - H04W 88/12: Access point controller devices - H04W 12/06: Authentication - H04W 36/08: Reselecting an access point - H04W 36/18: for allowing seamless reselection, e.g. soft reselection - H04W 52/12: Outer and inner loops - H04W 80/04: Network layer protocols, e.g. mobile IP [Internet Protocol] - H04W 88/06: adapted for operation in multiple networks {or having at least two operational modes}, e.g. multi-mode terminals - 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 When a network pages the temporary user mobile identifier of a mobile station, the mobile station sends a response to the network. Next, the network checks the authenticity of the user using a ciphering key, corresponding to the temporary user mobile identifier and a random number. If the temporary user mobile identifier is authenticated, a normal incoming call acceptance procedure is executed. If the mobile station is authenticated although the temporary user mobile identifier is wrong, the network reassigns a new temporary user mobile identifier to the mobile station and stops the current communication. In communication, the network and the mobile station mutually notify encipherment-onset time and negotiate about encipherment manner with each other. In addition, diversity handover is commenced upon a call attempt. Furthermore, if a branch replacement is necessary, the current branch is replaced by new branches capable of executing the diversity handover. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, the mobile station uses the same branch structure and the same communication frequency band for all of calls. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, a branch structure and a communication frequency band, which can continue all of the calls, are selected and used. Therefore, the mobile communications system is suitable for transmission of various sorts of data in accordance with the development of multimedia. ## Claims ### Claim 1 A mobile station wirelessly communicating with a network, comprising: a processor of a computer system and a storage which stores a computer program executable by the processor to implement: a decipherer responsive to reception of an enciphering start request from the network to become set, before the mobile station sends the network an acknowledgement of the enciphering start request, to decipher a downlink signal from the network; and an encipherer that becomes set to encipher an uplink signal to the network only after the mobile station sends to the network the acknowledgement of the enciphering start request. ### Claim 2 A wireless communication method performed by a mobile station to wirelessly communicate with a network, comprising: computer executable steps performed by a processor of the mobile station to implement: responsive to reception of an enciphering start request from the network, becoming set, before the mobile station sends the network an acknowledgement of the enciphering start request, to decipher a downlink signal from the network; and becoming set to encipher an uplink signal to the network only after the mobile station sends to the network the acknowledgement of the enciphering start request. ### Claim 3 A mobile station wirelessly communicating with a network, comprising: a processor of a computer system and a storage which stores a computer program executable by the processor to implement: an encipherer responsive to sending of an enciphering start request to the network to become set, before the mobile station receives an acknowledgement of the enciphering start request from the network, to encipher an uplink signal to the network; and a decipherer that becomes set to decipher a downlink signal from the network only after the mobile station receives the acknowledgement of the enciphering start request from the network. ### Claim 4 A wireless communication method performed by a mobile station to wirelessly communicate with a network, comprising: computer executable steps performed by a processor of the mobile station to implement: responsive to sending of an enciphering start request to the network, becoming set, before the mobile station receives an acknowledgement of the enciphering start request from the network, to encipher an uplink signal to the network; and becoming set to decipher a downlink signal to the mobile station only after the mobile station receives the acknowledgement of the enciphering start request from the network. ### Claim 5 A base station controller situated in a network wirelessly communicating with a mobile station, comprising a processor of a computer system and a storage which stores a computer program executable by the processor to implement: a decipherer responsive to receipt of an enciphering start request from the mobile station to become set, before the network sends an acknowledgement of the enciphering start request to the mobile station, to decipher an uplink signal from the mobile station; and an encipherer that becomes set to encipher a downlink signal to the mobile station only after the network sends the acknowledgement of the enciphering start request to the mobile station. ### Claim 6 A method performed by a base station controller situated in a network wirelessly communicating with a mobile station, the method comprising: computer executable steps performed by a processor of the base station controller to implement: responsive to receipt of an enciphering start request from the mobile station, becoming set, before the network sends an acknowledgement of the enciphering start request to the mobile station, to decipher an uplink signal from the mobile station; and becoming set to encipher a downlink signal to the mobile station only after the network sends the acknowledgement of the enciphering start request to the mobile station.