Telefonaktiebolaget Lm Ericsson (publ)

Jan-Erik Uddenfeldt

Bengt Y Persson

Alex K Raith

Olov H Eriksson

The invention relates to a method in mobile radio systems in which the responsibility for transmitting message information to a mobile station (MS.sub.1, MS.sub.2) is handed over from at least a first base station transmitter (B.sub.ma, B.sub.mb) to at least a second base station transmitter (B.sub.na, B.sub.nb). In accordance with the invention, the same radio channel is used, if possible, before and after the handover for transmitting message information to the mobile station. If the same radio channel can be utilized, the handover takes place without the mobile station being informed beforehand of the handover by a special signal or order or the like. In digital mobile radio systems with digital transmission of message information by digital modulation of the radio signals, the transmission is preferably started from a second base station transmitter before the transmission is terminated from a first base station transmitter. During a transmission time substantially the same message information is transmitted to the mobile station from both at least one first and one second base station transmitter.

Handover method for mobile radio system

The invention relates to a method in mobile radio systems in which the responsibility for transmitting message information to a mobile station is handed over from a first base station transmitter to a second base station transmitter. In this method, the same radio channel is used, if possible, before and after the handover for transmitting message information to the mobile station. If the same radio channel can be utilized, the handover takes place without the mobile station being informed beforehand of the handover by a special signal or order or the like. In digital mobile ratio systems with digital transmission of message information by digital modulation of the radio signals, the transmission is preferably started from a second base station transmitter before the transmission is terminated from a first base station transmitter. During a certain transmission time substantially the same message information is transmitted to the mobile station from both the first and second base station transmitters.

A method of reducing blockages and call interruption in handling over calls in a cellular mobile radio system. When the signal strength from a base station to a mobile and vice versa falls below a given value the handover shall take place to another base station. In order that the call will not be interrupted, a smaller number of channels are reserved, so-called rescue channels, from the ordinary channels in the system. The rescue channels can be fixed or dynamic for a given base station.

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Vallingby, Sweden

Jan-Erik Uddenfeldt