Experimental Evaluation Of Transmission Link Characteristics In Body Area Networks

Recent advances in digital electronics, embedded systems, and wireless communications have led the way to a new class of distributed Wireless Sensor Networks (WSNs). A Body Area Network (BAN) is a WSN consisting of miniaturized, low-power, autonomous, wireless biosensors, which are seamlessly placed or implanted in the human body to provide an adaptable and smart health care system. The possible applications of BAN are in health care services and medicine, assisting persons with disabilities, and entertainment and sports. The nodes in a BAN generally use IEEE 802.15.4 radios which have low- power consumption and are relatively immune to interference. In this thesis, we present the results obtained by performing multiple experiments by placing these sensor nodes on the human body. The focus of our work is to observe how the values for Packet Reception Rate (PRR), Received Signal Strength Indicator (RSSI), changes in distances, and transmission power levels, vary when the experiments are performed off and on the human body. We observe and analyze how these values vary when a single sender node transmits to a single receiver node, and when multiple senders transmit to a single receiver. The results show that the human body possesses challenges with respect to the communication of sensor nodes. The human body seems to adversely affect the radio propagation and communication such that nodes on some parts of the body may have limited connectivity to nodes on other parts. We notice that the human body itself, not only affected radio propagation but also led to attenuations in signal levels received by on-body sensors, as a result of which the nodes had varied connectivity between them