These stages are realised extensions based on the Proof of Concept and Evaluation studies. Following preliminary site-survey studies of applicable sites, small scale pilots are used to demonstrate the feasibility of in-situ (scalable) solutions. These may or may not be integrated into the customer’s network and instead operate on a segregated network for test and evaluation purposes. System performance at this stage is indicative of actual performance on full deployment and therefore a lot of optimisation work is usually carried out to achieve maximum performance.