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.

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.

Abstract: 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.

Abstract: A method and apparatus for achieving reliable transmission of signalling messages in a cellular system in which the frequency plan, frequency/time slot allocation plan, code channel allocation plan, or dynamic/adaptive channel allocation rule of the system is violated by allowing adjacent base stations to reuse particular frequencies/time slots/channels for signalling a particular mobile station. In situations where signalling messages, such as handoff commands, which are communicated between a base station and a mobile station are not properly received by the mobile station, an alternate communications channel will be established to ensure the reception of these messages. The alternate channel is provided by repeating the message through a channel associated with a base station which has better radio characteristics. The channel selected for transmission of the message by the new base station will be on the same frequency/time slot/code as used by the established connection.

Abstract: A method and apparatus are disclosed for supervising a communication link in a cellular mobile radio system between a base station and a mobile station on a digital voice channel by utilizing digital voice color codes. The base station transmits bursts of communication data, which have an associated digital voice color code, to the mobile station. The mobile station, upon receiving the bursts and decoding the digital voice color code, compares the digital voice color code with a reference digital voice color code received during a call setup or handoff operation. A timer is initiated to time out the communication link after a predetermined period of time in response to the reference digital voice color code not being equivalent to a first predetermined number of the digital voice color codes received with the bursts.

Abstract: A method of supervising the subscribers in a mobile telephone system to detect audulent use of a mobile telephone. A fraudulent subscriber (MS2) can have the same identification number (12) as that (11) of a legitimate subscriber (MS1) and the operator of the system cannot discover the fraudulent use. According to the proposed method, a predetermined sequence of numbers (00, 01, . . .20) is assigned to each mobile telephone in the system. When a call is made by a subscriber across a control channel it is followed by a particular number in the sequence across the allotted voice channel and this order number is recorded in the toll-ticketing records in the mobile switching centre (MSC). When the next call is made from the same subscriber, the next order number is sent and recorded. Thus all the calls from a legitimate subscriber are recorded in a determined sequence.

Abstract: An arrangement for protection of circuits in a telephone exchange against overvoltages like for example lightning transients or so called longitudinal disturbances appearing on the lines connected to the exchange. The arrangement having at least two non-linear electronic circuit elements (T2, T3) which selectively shunt the overvoltages to ground, the junction between the conduction states, conducting-non-conducting, for at least one of the circuit elements being controllable.

Abstract: A device for providing phase synchronism of a transit station in a digital telecommunication network, comprising within a phase-locked loop a voltage-controlled oscillator that has an output arranged to supply a station clock signal and a control input actuated by line clock signals pertaining to a plurality of incoming lines from other transit stations in the telecommunication network and a phase comparator that is arranged to compare the phase of the station clock signal with the phases of the line clock signals and has an output connected to the control input of the voltage-controlled oscillator via a loop filter.

Abstract: A digital data switch of the time-space-time (TST) type for switching pulse code modulated (PCM) data is disclosed. The switch combines a parity bit with each PCM word being switched in a conventional way to supervise the internal operation of the switch. The invention consists of a method of using such a switch for checking that a correct or intended connection is made through the switch by inserting incorrect parity with PCM words to the input in question immediately after the connection is established and checking the outlets of the switch to determine the output/s having incorrect parity. The check is made by the central control of the switch which compares the output/s having incorrect parity with the intended output/s. A simple circuit arrangement for distinguishing deliberately introduced wrong parity from through connection faults is also disclosed.

Abstract: A method and apparatus for switching PCM data in a telephone exchange wherein the switch is of the time-space-time (TST) type comprising a plurality of identical inter-connected groups, each group having two separate planes in which connections may be established. A plane select bit of data is added to each speech sample before switching through the space switching stage. The plane select bit influences a logic circuit at the switch output to determine which plane provides the outgoing data. For reliability connections are duplicated, that is, made in both planes until congestion occurs and when congestion occurs a new call is made in a path of one of the planes previously used for duplication. Information relevant to unduplicated connections is stored in a memory external to the switch to enable unduplicated connections to be re-established if they should be lost due to a fault.