The Universal Mobile Telecommunications System (UMTS) has been developed in order to create a unified telecommunications system with multimedia capabilities. UMTS uses the Code Division Multiple Access (CDMA) technique. In this type of system, all users share the same frequency at the same time. Interference then plays a major role in the behaviour of a CDMA network and causes the coverage to vary according to the load. Furthermore many parameters have an impact on the coverage (spreading factor, user rate, transmission power etc...). So motivating students to learn CDMA concepts is often difficult because they find it very difficult to understand the physical phenomena. To overcome this problem, students need to practise several laboratory exercises. Then they need a suitable simulation tool. In this paper a simple cellular model is introduced and a CDMA software based on that model is described. Its effectiveness as a teaching method is explained. This simulator can help students to understand the CDMA network behaviour more accurately.