Letter to the Editor Evaluation of Implant Communication with Polarisation and Unslotted CSMA/CA Protocol inWireless Body Area Networks

In [1], authors show that the implant’s effective radiated power (ERP) and receive signal strength indication (RSSI) are affected by the depth inside a human body. Neither the polarisation of the implant nor the effect(s) of the implant’s distance (from the base station) and the power settings (at the base station) on the RSSI is considered. With regards to the MAC part, the authors of [1] discourage the use of the CSMA/CA protocol for WBAN due to unreliable clear channel assessment (CCA) in the medical implant communication service (MICS) band. There is no discussion on the MAC performance of the CSMA/CA protocol for WBAN. In this letter, we extend the results of [1] by considering the effects of the implant’s polarisation, distance, and the power settings (at the base station) on the ERP and RSSI. We further analyze the behavior of the CSMA/CA protocol for WBAN. For the performance analysis of the CSMA/CA protocol, we consider the unslotted CSMA/CA protocol used in a nonbeacon IEEE 802.15.4 mode [2].