Dissertation (MSc Telecommunications Engineering)Recently, in most of the developing countries like Tanzania, life expectancy and the inherent costs of caring for an aging population are increasing. These have put an enormous demand on the health care systems and have driven the advancement of technology-based sensor devices that can remotely monitor key vital life signs. These advancements enabled proliferation of wireless sensor networks. These sensor networks are capable of monitoring and controlling environments remotely, thereby reducing the workload of medical care. Body area networks (BAN) have revolutionized the remote patient monitoring system. Sensors implanted in the body collect the vital life sign data and report any anomaly to a physician via wireless technology. In this dissertation, a performance study of zigBee/IEEE 802.15.4 standard for BAN was done through simulation using OPNET Modeler based on three zigBee network topology formations (cluster, mesh and star). Analysis of these topologies in various scenarios was done to compare them based on different performance metrics including throughput, data traffic sent, data traffic received, load and end-to-end. Simulation results show that the zigBee/IEEE 802.15.4 has better throughput and network usage when cluster topology is used compared to star and mesh topologies. Similarly its traffic sent, traffic received, load and end –to-end delay were better than other two topologies. Hence cluster topology can be used with efficiency in WBAN for patient vital signs monitoring.