Abstract: A cellular radio system includes cells or cell groups complementing the network capacity locally. These cells or cell groups have not been presented as neighboring cells for the surrounding network. This means that a mobile station of the cellular radio network will not at any stage become aware of these compelementary separate radio coverage islands on the basis of the neighboring cell information received from a base station. The coverage of these separate cells and cell groups may topologically overlap the other cells of the cellular radio network. An access of the mobile station to the cells of a compelementary system is based on its a priori information of at which frequencies such a complementary radio coverage may be found (depending on the location of the mobile station). At least part of the mobile stations have then an automatic or user-operated facility of scanning these frequencies.

Abstract: A digital TDMA/FDMA (Time Division Multiple Access/Frequency division Multiple Access) cellular network system, suitable for a microcellular network and to maximize the advantage to be gained from interference diversity, including base stations forming radio cells, each having a determined static frequency of a channel of the cell and including a first transceiver continuously transmitting control data of the system concerning the cell at the control channel frequency, at least in one predetermined time slot of a TDMA frame. The TDMA frame of the first transceiver includes traffic channels at least in a part of the other time slots. Each base station further includes at least one second transceiver for the traffic channels. The system further includes mobile stations connected to the base stations via a radio path.