Abstract
Wireless body area networks (WBANs) are yet another milestone achieved in automating the human environment for pervasive applications. The small, miniaturized design of these sensors is giving way to many applications, including e-health, lifestyle, gaming, and disaster recovery. WBANs are expected to increase life expectancy by performing preventive tasks on time. The patient could be treated in time due to continuously being in touch with the medical health service. This can also lead to decreasing the cost of medical expenses by avoiding extreme conditions. However, the point to ponder about these networks is the transfer of information, which is dealt with by the routing strategies. In order to combat and maintain a trade-off between the reliability and energy efficiency, a number of routing algorithms have been designed that work in conjunction with a prescribed topology. This chapter aims to provide a survey on the existing routing protocols for WBANs in terms of intra-WBAN and inter-WBAN communication. We classify intra-WBANs as thermal aware, cluster, cross-layer, delay tolerant, location based, and quality of service (QoS) based. For inter-WBAN communication, a list of available techniques on the physical, data link, and network layers is discussed.