The code for IEEE 802.15.6: Wireless Body Area Network (WBAN) is available on the ns3 App Store: https://apps.nsnam.org/app/wban/
This module describes the implementation of the WBAN PHY layer in accordance with the standard specifications.
It also includes the BodyPropagationLossModel, which calculates path
loss and evaluates the interference caused by the presence of a human
body within the network. Please refer to the documentation for installation and implementation details of the WBAN PHY and propagation loss model.