Estimating subscriber terminal speed, selecting cell, and radio system

A method for selecting a cell in a radio system comprising a plural number of microcells and at least one umbrella cell covering the microcells;

• the radio system comprising:
• actively operating at least one base station and a subscriber terminal either in a microcell or in the umbrella cell;
• and
• repeatedly measuring and storing at, at least one base station or subscriber terminal at different points in time, a power of a received signal, the transmission power of the signal being substantially constant or known, wherein using the measured powers of the received signal for producing a probability representing an interdependence between powers measured at least at two different points of time, the probability being used for estimating a movement of a subscriber terminal, and
• selecting, on the basis of the estimated movement of the subscriber terminal, either a microcell or an umbrella cell as a cell for the active operation of the subscriber terminal.

The radio system comprising:

• at least one base station and a subscriber terminal, which is arranged to function actively either in a microcell or an umbrella cell;
• at least one base station or subscriber terminal being arranged to repeatedly measure and store at different points of time a power of a received signal, the transmission power of the signal being substantially constant or known,
• wherein the radio system is arranged to use the measured powers of signals to produce a probability representing an interdependence between powers measured at least at two different points of time, the probability estimating a movement of a subscriber terminal, and
• the radio system is arranged to select, on the basis of the estimated movement of the subscriber terminal, either a microcell or an umbrella cell as a cell for the active operation of the subscriber terminal.