Wireless Sensor Networks (WSNs) have diverse application domains such as smart home, smart care, industrial, etc. We present a WSN system based on the ZigBee technology (IEEE 802.15.4) in Smart Home. In our paper we interest to ZigBee protocol is often used in medical Rehabilitation, which is a relatively new concept involving wireless transmission of data from the sensors attached to a patient to a distant monitoring station. There is no standardized topology managing the current networks, therefore, we will compare and evaluate the performance the mobility of nodes for star topologies in different scenarios to determine which is the most suitable in a typical hospital environment. The study of performance is based on measurements of the Received Signal Strength Indicator (RSSI) in different position in the Room of test using STM32F04 board. The analysis will be performed in OPNET comparing characteristics such as transmission efficiency and network delay.