Investigating on the Interferences on Human Body Communication System Induced by Other Wearable Devices

Human body communication (HBC) has become one of the most energy-efficient candidates for wireless body area network (WBAN) as it uses higher conductivity of human body as transmission media to reduce transmission loss. The use of medical electrodes instead of bulky antennas makes it suitable for biomedical sensors. The IEEE 802.15.6 standard has reserved only one communication channel for HBC centering at 21 MHz with 5.25 MHz bandwidth, which enlarges the probability of the collision and interference when multiple wearable devices locate on the human body. As a result, the error vector magnitude (EVM) of HBC will be affected by the various states of the interference sources. However, none of the previous works has studied the effects of interferences in HBC. In this paper, the interference factors in HBC WBAN systems assisted by actual measurement on human body are investigated. The HBC signal EVM under different interference states are studied, including frequency, power, modulation scheme, symbol rate, and apart distance between interference source and receiver of HBC. Based on the result and analysis, we propose a possible communication scheme for other body nodes to avoid the collision with HBC.