A method for deriving pathloss estimation values within a cellular communication network. The method comprises receiving pathloss data obtained from a plurality of wireless communication units located within the cellular communication network, receiving location information corresponding to the plurality of wireless communications units, associating received pathloss data with individual sectors within a coverage area of the cellular communication network based at least partly on the location information for the respective wireless communications unit, and deriving pathloss estimation values for individual sectors within the cellular communication network based at least partly on the received pathloss data.