A system is provided for optimisation processing in a cellular communications network having a central element (30) and a number of distributed network elements (40, 42, 44, 46, 48, 50). Each network element (40 50) is coupled to the central element, and each is arranged to obtain optimisation data and has a pre-processing arrangement (120) for pre-processing the optimisation data. The central element (30) then receives and processes this pre-processed optimisation data to produce optimisation code for optimising the performance of the network. In this way less data needs to be backhauled to the central element (30), and less processing is required at the central element (30), thereby improving the scalability of the network.