Since the signal transmission in WBANs takes place around or in the human body, the channel fading significantly affects the error performance of the networks. In this paper, the authors investigate MAC performance of an IEEE 802.15.6-based WBAN operating over a Rician-faded channel. They deploy Bit Error Rate (BER) as a function of channel quality, diversity order, and Signal to Noise Ratio (SNR) values for all User Priorities (UPs) in analytical and simulation models to evaluate the MAC performance. They study how varying Signal to Noise Ratio (SNR) of all UPs affects the MAC performance. Their results indicate that data frame sizes and channel quality between a node and the hub are the most effective parameters on PHY/MAC performance of a WBAN.