System loss analysis in body area networks with space diversity scheme

This paper presents an analysis of the system loss in dynamic off-body communications, based on measurements performed at 2.45 GHz in an office environment. The localization and number of the antennas on a human body influence on the power of received signal. The configuration of two antennas mounted on the different part on human body ensure the higher probability to receive signal with good quality independently to the position of the antennas. The measurement equipment and measurement procedures are described. The mean system loss is in the range of 54.42 dB and 64.28 dB. The difference coefficient between mean values of system loss corresponding to two wearable antennas is in the range of 0.69 dB and 8.76 dB. The standard deviation of the mean system loss is in the range of 6.46 dB and 7.39 dB. Measured correlation coefficient between signal received by two wearable antennas for each scenario is in the range [−1.25.10−3, −1.01· 0−1]. The statistical analysis showed that using space diversity scheme can ensure better quality of the received signal.