Two important high bandwidth wireless certifications in our days are Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Fidelity (WiFi). They can interoperate to form a wide geographical network in which Mobile Client (MC) can move. We suppose a combination of two WiFi Access Points (AP) and a WiMAX Base Station (BS) that interoperate putting a WiMAX Wireless Network Interface Card (WNIC) in the WiFi AP. The BS can request real time video or Video on Demand (VoD) from a server allocated in the fixed network (to which the BS is connected.) In order to model the movement of the MC, we build a diagram state to represent the areas in which MC can stay, and from what area to which one the MC could pass. Classifying the areas in connected and disconnected ones, we can discover the different actions that are achieved by different entities of a simple protocol, that are allocated in the BS and the AP. These entities are in charge to control the buffers to efficiently support disconnections due to handover and out of coverage situations (disconnected states). Our algorithm is based on Received Signal Strength Indicator (RSSI) measurements. These RSSI values are used to change the state in the diagram state. But to predict the next state of MC, we use a new prediction technique that we call RSSI Gradient Predictor. We test our predictor using some synthetic proposed RSSI values for different MC movement shapes, these movements include Regular and Irregular movements. The results show a good behaviour of our algorithm.