Telefonaktiebolaget Lm Ericsson (publ)

Jan E Dahlin

Paul W Dent

Alex K Raith

Walter Ghisler

Harald Kallin

Bengt Y Persson

Anders C Hoff

Georg William Chambert

Jan E Uddenfeldt

Ake L Ramstedt

Krister A Raith

Walter G Mueller

Hans J Roxbergh

Lars R Waerme

John R Bohaychuk

Monica B Madebrink

Bo G Svensson

Nils P Taylor

Gunilla A Bergling

Sven G Nordstrom

Method and arrangement for increasing the range for a telecommunication

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 carded out. In one embodiment, only the bi-directional authentication check is carried out.

Method of carrying out an authentication check between a base station

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.

Reconfiguration in a cellular communications network

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. In this way, analog and dual-mode mobile stations may benefit from the advantages of monitoring digital control channels and digital paging channels including multiple pages per channel and battery-saving capabilities.

Cellular telephone for monitoring analog and digital control channels

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.

A synchronizing method in a mobile radio system which operates with Time Division Multiple Access (TDMA) but which lacks global time reference for all base stations and mobiles in the system. The inventive method is intended for ciphered transmission of data and speech in accordance with a given ciphering key (E2). When handing-over a call, the ciphering synchronism is lost. In accordance with the method, subsequent to hand-off (the time t.sub.2), the take-over base station (BS2) signals non-ciphered information (S1) to the mobile (MS) disclosing the number of frames (R1-R13) which shall pass until ciphering can again be commenced, calculated from a given frame (R1). Call information is transmit the following frame (R2), this information now being ciphered with the aid of a ciphering key (E1) different to the original key. This other ciphering key consists of a periodic bit sequence having a period which is equal to one frame interval.

Synchronizing method in a mobile radio system

The invention relates to a method in a mobile radio system having both digital and analog radio channels. An object of the invention is that a connection established on a digital radio channel often shall be possible to maintain even when the time dispersion on available digital radio channels exceeds the designed maximum time dispersion of equalizers in receiving stations. According the invention equalizers in the receivers of the system may be designed for a smaller maximum time dispersion than the total time dispersion the whole system shall be capable to handle. Instead handoff is made to an other channel when the time dispersion of a used digital channel tends to become too big. When an other digital radio channel with low time dispersion is available handoff is preferably done to this channel. Alternatively or in the absence of such a digital radio channel handoff is performed to an analog radio channel.

Method of maintaining an established connection in a mobile radio system

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.

Mobile assisted handoff

A method and system in which the control channels of an associated base station directly correspond to certain time slots of a radio channel frame, which also includes time slots being utilized for traffic channels. The time slots being utilized as control channels are marked with uniquely defined control channel indicators which include unique Sync Words and unique control channel identification words. The mobile station recognizes the uniquely defined control channel indicators and identifies those particular time slots as control channels so as to distinguish from the time slots which are not being used as control channels.

Method and system for uniquely identifying control channel time slots

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.

Method of transmitting signaling messages in a mobile radio

A method in a mobile radiotelephone system in which an address is added to a symbol message in a control channel in order to exclude interfering connections operating on the same radio frequency as the actual connection between a base station and a mobile station. According to the proposed method, the address (A1) to the intended receiver is added to the message (M) and an error check word (E) is calculated based on both the address (A1) and the message (M). Before transmitting to the receiver, the added address is removed and the transmitted control signal includes only the symbol message (M) and the error check code (E). In the receiver, the specific address for the receiver is added to the received control signal and the same calculation is carried out as in the transmitter in order to get an accept/reject signal.

Method of processing a radio signal message

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.

Handoff procedure that minimizes disturbances to DTMF signalling in a

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.

Combined analog and digital cellular telephone system having a secondary

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.

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Jarfalla, Sweden

Jan E Dahlin