Abstract: A method for allocating emergency speech items in a mobile communication system comprising a network infrastructure (BS), a first subscriber station (MS1) connected to it, and at least one other subscriber station (MS2, MS3), the method comprising maintaining a group call consisting of speech items between the first subscriber station (MS1) and at least one other subscriber station (MS2), transmitting an emergency speech item demand (101) from the first subscriber station (MS1), which is in an emergency, to the network infrastructure (BS), and transmitting an emergency speech item grant message (102) from the network infrastructure to the first subscriber station. The method further comprises transmitting, to the at least one other subscriber station (MS2, MS3), emergency speech item information (103) containing the identifier of the first subscriber station (MS1) and indicating that an emergency speech item has been allocated (102) to the first subscriber station.

Abstract: A method of synchronizing a telecommunications connection in a mobile communications system having at least one base station, and having a first and at least a second mobile station communicating on a direct mode channel, the first mobile station operating on the direct mode channel transmits a registration message to the base station of the mobile communications system on a system channel of the mobile communications system, the registration message indicating a wish of the first mobile station to operate in dual watch mode on the control channel of the mobile communications system. In response to the registration message, a specific control channel of the base station and the timing information related to the control channel are communicated to the first mobile station, the first mobile station switches to dual watch mode in order to communicate either on the direct mode channel or on the allocated control channel during the time indicated by the timing information.

Abstract: A method for allocating time slots in a mobile communication system including a base station and mobile stations, the base station communicating with the mobile stations on a radio frequency divided into TDMA frames, which are further divided into time slots, of which at least one can be allocated as a traffic channel of one or more of the mobile stations, including the steps of transmitting information from the base station to a mobile station on the allocation of a time slot other than a traffic time slot used by the mobile station as a signalling time slot common to the mobile stations communicating on the radio frequency, starting to use the respective time slot as a signalling time slot common to the mobile stations communicating on the radio frequency in the signalling traffic between the base station and the mobile stations in such a manner that the mobile stations can also communicate in one or more of the traffic time slots on the radio frequency.

Abstract: A method for controlling a subscriber station operating on a direct mode channel in a mobile radio system. The mobile radio system is one which includes a radio network with at least one base station and subscriber stations, and at least one subscriber database and further, at least one repeater station, which forwards traffic between the at least one base station and the subscriber stations operating on a direct mode channel. In the method, a subscriber station is registered in a radio network via a base station. The subscriber station transmits a detachment message to the base station, and indicates that it is switching to operate on a direct mode channel. In order that the radio network is able to control and communicate with the subscriber station switched to the direct mode channel, the identifier of the repeater station via which repeater station operating on the direct mode channel can be reached by the radio network, is transmitted to the radio network.

Abstract: A method for allocating control channels in a radio system having base stations and subscriber stations communicating with respective ones of the base stations on control and traffic channels. To make the control channel operation more efficient and to avoid interference, traffic channels are allocated for control channel use so as to distribute the control channel operation between a greater number of channels, the channels allocated for control channel use being indicated to the subscriber stations and control channel operation is performed on the control channels allocated in a distributed manner.

Abstract: A method for establishing a connection between a first communication device, connected to a communication network and having at least one identity, and one or several second communication devices, connected to the communication network and located in a limited location (i.e., paging) area, each of them having at least one identity. In order that the user of the system may define the location area dynamically, the first communication device sends to the communication network a message containing an identification of the location area and the identity of one or several second communication devices and the communication network calls at least one subscriber device provided with the identity only in the location area defined by the location area identification.

Abstract: A method and an arrangement for subscriber location management among a group of radio networks comprising at least two radio networks (101, PMR1, PMR2) in which at least some of the subscribers (SBR1, SBR2, SBR3) may roam away from the home network and register in another radio network over the radio path. To enable centralized subscriber location management, the subscriber database (HLR) of one radio network (101) is arranged to maintain in a centralized manner the location data of all subscribers (SBR1) that have roamed outside their home networks and registered in another radio network (PMR2) at least with an accuracy of a radio network.

Abstract: A method for realizing a group call in a digital radio network wherein a plurality of mobile subscribers participating in the group call roam within the area of at least one base station. Subscribers participating in the group call are guided one by one to talk on the same radio channel. To be able to handle the traffic in a controlled manner at all times without the subscribers congesting the radio channel by talking simultaneously, the base station is informed of the subscriber's desire to speak after the respective subscriber has indicated his or her desire to speak with predetermined signalling, the next speaker is selected at the base station on the basis of a predetermined algorithm, and the base station transmits an indication of a turn to speak to the subscriber which at the time is the next speaker.

Abstract: A random access method in a radio system having a plurality of radio stations and at least one base station serving the radio stations, in which the base station transmits an invoking message to the radio stations in a first time slot to grant the radio stations the right to send a random access message to the base station. One of the radio stations transmits a random access message containing a random identifier to the base station in a second time slot subsequent to the first time slot. The base station transmits a response message containing the random identifier to the radio station in a third time slot subsequent to the second time slot. In order to avoid allocating the same telecommunications resource for simultaneous use by more than one of the radio stations, the response message sent by the base station to the radio station in the third time slot contains the identifier of the second time slot.

Abstract: The invention relates to a quadrature modulator comprising a circuit for the compensation of a local oscillator leak signal in an output signal of the modulator, which circuit adds different compensation voltages to two modulation signals. To provide an automatic compensation of the local oscillator leak signal, the quadrature modulator of the invention comprises a regulating circuit for the regulation of the intensity of the compensation voltages irrespective of each other on the basis of the correlation between the amplitude variation in the output signal and the corresponding modulation signal.