# A Survey on Mobility Support in Wireless Body Area Networks
## 1 Introduction  
Healthcare always remains the highest priority. In addition, recently several network technologies, such as wireless ad hoc and sensor networks, enable us to use their approaches for healthcare application. Small sized sensor nodes around the body are involved in gathering medical information and transmitting them toward the sink node, which is supposed to communicate with nodes in Internet. With the help of such technologies, both patients and doctors can be updated anytime and anywhere so they can handle emergency situations. Furthermore, a number of smart applications have emerged in several domains including telemedicine and data gathering for scientific research [1; 2; 3]. However, the existing network technologies such as pure ad hoc and Wireless Sensor Networks (WSNs) are not feasible to meet specific requirements; therefore, special Wireless Body Area Networks (WBANs) have been proposed and attracted interests of researchers in the community. Even though communication between sensor nodes is a big, common concern in both WBANs and WSNs, there are also fundamental differences between them in terms of network environments and requirements. For instance, (i) varying bandwidth of communications through body rather than space; (ii) energy dependent heterogeneous nodes; (iii) strict constraints for power consumption; and being (iii) harmless to the body tissues are unique characteristics of WBAN compared to WSN; therefore, new hardware and software are proposed to deploy various WBAN applications in the real world. Here, we review one of the software architectures. [PERSON] et al. [4] proposed efficient software framework and signal-processingapplication. Signal Processing In Node Environment (SPINE) provides Application Programming Interfaces (APIs). Therefore, it is reasonable to define SPINE as middleware running between coordinator (sink node) and sensor nodes. Furthermore, platform independent communication protocol layer in SPINE contains an abstract layer where IEEE 802.15.4 and Bluetooth are implemented. In more detail, SPINE consists of two main components: SPINE node and Coordinator. SPINE node is implemented by the embedded programming language and SPINE Coordinator by Java. SPINE node is composed of four interacting components, sensor node manager, communication block, sensing management and signal processing. They control all relevant functions to manage duty cycle, various timers and communications. SPINE Coordinator provides APIs for six main functions and four states. With the help of SPINE, each function is used to build rapid prototypes for WBAN nodes. As an extension of SPINE, Collaborative SPINE (C-SPINE) [5] was proposed to improve the SPINE by employing multiple coordinators called Base Station (BS) and information exchange with the help of Over-The-Air (OTA) protocol in inter-Body Sensor Networks (BSNs). C-SPINE operates in the same way as SPINE for non-collaboration applications. On the other hand, in the case of collaboration application, corresponding service is activated by following procedures, BSN service selection and activation, application-specific service, BSN proximity detection protocol and BSN service discovery protocol, which discovers neighbor BSs after exchanging lists of available services between them. Besides software frameworks, there are several good survey papers [6; 7; 8; 9] to address the key technologies as well as research challenges, such as security and low power computing, and these present further research trends. Especially, [PERSON] et al. [9] emphasized the communication technique for rapid development and deployment of WBAN systems that support remote monitoring systems in residential environments. Furthermore, multi-sensor fusion in BSN-based human activity recognition was addressed in [10; 11]. Sensor fusion strategies in BSNs were explained with domains of emotion recognition and general-health.