Nokia Mobile Phones Limited

Eero Sakari Makikallio

Mika Jari Tuutijarvi

Raimo Tapio Klemetti

Jorma Antero Savolainen

Hannu Pakonen

The invention is related to a method for improving handover in reception and transmission in a digital cellular mobile communication system including base stations and mobile stations, in which mobile station receives from a base station a handover command in the middle of speech reception or transmission on a first reception or transmission channel, whereby in the handover, the reception/transmission is changed to a second reception or transmission channel. Particularly the invention is related to mobile communication systems based on time division multiple access, in which transmission and reception occur in bursts in separate time slots. In the method according to the invention, speech is sampled, or, in transmission, it is A/D converted (32), and in reception, it is D/A converted (22) during the handover and stored in memory, e.g. in buffers, and taken into use in reception during the handover by D/A converting (24) it for a loudspeaker, and in transmission, by transmitting (34) it immediately after the handover. This method shortens the silent period in the handover.

Method for improving handover

The strength of the signal or carrier in one or more transfer channels near the receiving channel of a radio device operating in a radio telephone system is measured, for example, with a MAHO measurement. The measurement result is used to calculate the disturbance caused by the transfer channel to the receiving channel, and, based on the acquired result, the frequency response of a filter included by the receiver is adjusted, for example, by changing the width or slope of the passband.

Method and circuit for filtering disturbances in a radio receiver

In the method of this invention, a mobile station is constructed to receive predetermined signals from neighboring base stations as an indication of received signal strength. These signals are compared to the current traffic signal strength indicator and a resultant signal is calculated proportional to the differential signal strength. Only the current received signal strength indicator is transmitted to the base station in absolute value. All other indicators are reported as relative values.

Simplified mobile assisted handoff of signal between cells

A power control loop for a radio frequency transmitter includes a power control amplifier, an output and a detector that is coupled to the output for providing an output power signal indicative of output power from the power control loop. A controller generates at least first and second reference signals. A differential amplifier provides a control output that is indicative of a difference between the output power signal and a reference signal. A dual rate filter couples the control output to the power control amplifier so as to vary its gain. The dual rate filter exhibits a fast-reacting filter mode when the controller changes the reference signals to the differential amplifier and a slow-reacting filter mode when the controller applies the first reference signal to the differential amplifier. The fast filter mode enables rapid feedback of the control output to the power control amplifier.

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Oulu, Finland

Eero Sakari Makikallio