recent evolution and technological advancement in wireless communications and micro­ electronics have enabled enhanced research trends toward wireless body area networks (wbans). this emerging new field of research plays an important role in medical and healthcare services. an electronic health (ehealth) monitoring system is one of the major applications of wbans that in addition to saving lives can provide cost-effective healthcare services by replacing the need for costly in-hospital monitoring with wearable or implanted monitoring systems that help early detection and prevention of any abnormal physiolog­ical activities that could risk the patients' lives. such a system continuously monitors the patient 's vital signs and helps patients to involve in their routine activities of daily life without requiring intensive or specialized medical services all the time, thus creating significant enhancement in the standard of living. one of the key challenges that limit the widespread usage of ehealth solutions in practical healthcare facilities is the limited battery life of sensor nodes (sns) that are needed to be replaced/ recharged manually once the energy is depleted. in most scenarios, battery replacement is not preferable, and it becomes highly unsuitable and impractical, especially when the sns are implanted inside the human body. this limited battery capacity of sns not only causes a performance bottleneck but is also likely to disrupt the future operations of sns, which may cause a life hazard. therefore, in order to have seamless and efficient implementation of an ehealth monitoring wban, improving the sns' lifetime or energy efficiency (ee) is of paramount importance. [...]