Position assignment in digital cellular mobile radio networks (eg GSM) derived from measurements at the protocol interface

Measurements are carried out at the protocol interface between base transceiver station and base station controller unit for optimization of the base station subsystem in an existing digital mobile network. At this interface it is possible - in contrast to measurements at the air interface - to gain mass data (e.g. received power, BER, signaling information) with low expenditure. The collected data allow however, only for a very rough estimation of the terminals' positions. In this paper a method is presented to assign measurement data from protocol interface to the related location of the mobile with the aid of field strength prediction. The application of the position assignment method is demonstrated within the GSM network. To validate this approach measurements were taken from the German GSM D1 net and were compared with exact position assignments by means of GPS. On the base of location assignment methods there are new experimental possibilities available, e.g. identification of traffic hot spots or areas of bad interference conditions.