Patents by Inventor Jan E. S. Dahlin

Jan E. S. Dahlin has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5434798
    Abstract: A method and apparatus for performing reconfiguration of a cellular network is provided. Cell parameters of affected mobile switching centers in the network are copied to a database, and the copied parameters are stored. A set of proposed changes to the stored parameters are prepared and the consistency of the prepared set of proposed changes is verified. Any necessary alterations to the set of proposed changes responsive to the verification are made and the verified set of proposed changes are copied to the affected mobile switching centers. The verified set of proposed changes are then introduced into the network. Additionally, at all times, an up-to-date image of all the cell parameters in all the mobile switching centers in the network is maintained in a system parameter database.
    Type: Grant
    Filed: May 23, 1991
    Date of Patent: July 18, 1995
    Assignee: Telefonaktiebolaget L M Ericcson
    Inventors: Monica B. K. Madebrink, Walter Ghisler, Ake L. Ramstedt, Anders C. E. Hoff, Sven G. Nordstrom, Gunilla A. Bergling, Nils P. Taylor, Bo G. Svensson, Lars R. Waerme, Hans J. Roxbergh, Jan E. A. S. Dahlin, Harald Kallin
  • Patent number: 5420911
    Abstract: The present invention is directed to a cellular mobile radio telephone system in which mobile stations may select either analog or digital control channels. Analog and dual-mode mobile stations are equipped to become multi-mode mobile stations which monitor both analog and digital control channels depending on the selected mode. Downlink multi-mode mobile stations, while required to use analog control channels for call access, may nonetheless scan digital control and paging channels to receive downlink control and paging communications from the land-based system. Bi-directional multi-mode mobile stations have the same capabilities as downlink mobiles but also are equipped to transmit control information to the land station over the uplink digital control channel. If no digital control channel is available, the multi-mode mobile stations scan primary and secondary sets of analog control channels.
    Type: Grant
    Filed: October 4, 1993
    Date of Patent: May 30, 1995
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventors: Jan E. A. S. Dahlin, Walter G. A. Mueller, Walter Ghisler
  • Patent number: 5390245
    Abstract: Methods for carrying out an authentication check in a mobile telephone system in which an authentic base station serves a plurality of mobile stations. A prior method carried out a unidirectional check from the base to a calling mobile, permitting a false base to carry out a false authentication check by collecting a number of so-called RAND-Response pairs. To avoid this problem, another unidirectional, base-to-mobile, authentication check and an authentication check from the mobile to the base are carried out. In one embodiment, only the bi-directional authentication check is carried out.
    Type: Grant
    Filed: April 7, 1993
    Date of Patent: February 14, 1995
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventors: Paul W. Dent, Alex K. Raith, Jan. E. A. S. Dahlin
  • Patent number: 5282250
    Abstract: Methods for carrying out an authentication check in a mobile telephone system in which an authentic base station serves a plurality of mobile stations. A prior method carried out a unidirectional check from the base to a calling mobile, permitting a false base to carry out a false authentication check by collecting a number of so-called RAND-Response pairs. To avoid this problem, another unidirectional, base-to-mobile, authentication check and an authentication check from the mobile to the base are carried out. In one embodiment, only the bi-directional authentication check is carried out.
    Type: Grant
    Filed: May 27, 1993
    Date of Patent: January 25, 1994
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventors: Paul W. Dent, Alex K. Raith, Jan E. S. Dahlin
  • Patent number: 5200957
    Abstract: The invention relates to a method for communication and handoff in a cellular mobile radio system and a base station and a mobile station for communication and handoff in such a system, in which time slot identifier codes are transmitted in bursts in times slots in frames of radio channels used for time division communication channels, the time slot identifier codes being indicative of burst time slot in a frame but not of transmitter or receiver entity or radio channel, the time slot identifier codes being used for burst synchronization and determining bursts the signal strength of which to be measured for the purpose of possible handoff.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: April 6, 1993
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventor: Jan E. A. S. Dahlin
  • Patent number: 5182753
    Abstract: In a mobile radio communications system, critical signaling messages, e.g., handoff messages, transmitted on a fast associated control channel and/or a slow associated control channel belonging to a digital traffic channel, are more heavily data protected than speech using convolutional coding and interburst interleaving. The coding and interburst interleaving are carried out so as to maintain compatibility with an exiting frame structure.
    Type: Grant
    Filed: June 15, 1992
    Date of Patent: January 26, 1993
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventors: Jan E. A. S. Dahlin, Krister A. Raith
  • Patent number: 5140627
    Abstract: Disturbances to DTMF signaling between mobile stations and the land-based system caused by handoff are minimized. DTMF signals are transmitted in real time between a mobile station and its associated base station. However, if during a DTMF transmission between a base station and the mobile switching center a handoff is requested, the handoff is delayed by a specified time in order to allow completion of the DTMF transmission. Alternatively, both base stations involved in the handoff transmit overlapping DTMF tones until the handoff is completed. If the handoff is requested before the start of the DTMF tone transmission, the DTMF transmission is delayed until the handoff is completed.
    Type: Grant
    Filed: October 9, 1990
    Date of Patent: August 18, 1992
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventor: Jan E. A. S. Dahlin
  • Patent number: 5119397
    Abstract: A method and apparatus for directing mobile stations in a cellular mobile radio system to different sets of control channels, depending on whether the land system and the mobile stations have digital capabilities. The mobile stations operate to initially scan the same primary set of control channels and to read one of them, and to make a determination, based on the value of certain bits transmitted over the control channel and also the digital capabilities of the type of mobile station involved, whether to continue operation on the primary set of control channels, or whether to scan and read any secondary set of control channels. If a mobile station with digital capabilities decides to scan the secondary set of control channels, but does not find such channels, the mobile station determines that there are no secondary sets of control channels. In this case, if the mobile has analog capabilities, the mobile station will return to scanning the primary set of control channels.
    Type: Grant
    Filed: April 26, 1990
    Date of Patent: June 2, 1992
    Assignee: Telefonaktiebolaget L M Ericsson
    Inventors: Jan E. A. S. Dahlin, John R. Bohaychuk
  • Patent number: 5042082
    Abstract: The invention relates to a method for communication and handoff in a cellular mobile radio system and a base station and a mobile station for communication and handoff in such a system, in which time slot identifier codes are transmitted in bursts in times slots in frames of radio channels used for time division communication channels, the time slot identified codes being indicative of burst time slot in a frame but not of transmitter or receiver entity or radio channel, the time slot identifier codes being used for burst synchronization and determining bursts the signal strength of which to be measured for the purpose of possible handoff.
    Type: Grant
    Filed: June 26, 1989
    Date of Patent: August 20, 1991
    Assignee: Telefonaktiebolaget L. M. Ericsson
    Inventor: Jan E. A. S. Dahlin