## 2 Related Work  
Vehicular communications emerged as a promising area for the deployment of safety and infotainment applications. A detailed study of the vehicular networking requirements, standards and solutions can be found in [17]. State-of-the-art vehicular networking studies [14] consider V2I and V2V interactions as the main trend for vehicular-related use cases. Usual applications, such as eSafety, traffic efficiency and data dissemination (infotainment), may require infrastructure-based end-to-end access through V2I architectures [18]. In these environments, MIPv6/NEMO [19] is the _de facto_ solution to the network mobility problem in V2I. With this solution, mobile routers (MR) belong to the subnet advertised by the road side units (RSU). Figure 1 illustrates a set of enabling technologies that apply to the vehicular networking use cases, of which the coverage ranges from local area to cellular [20]. Due to higher market penetration and ubiquitous coverage with broadband throughput, some recent FP7 initiatives [21] propose to handle V2I machine-type communications through LTE. The main technical motivations involve the conservation of an IPv6 end-to-end multi-hop communication model among heterogeneous nodes for in-vehicle embedded networks. On the other hand, the eHealth protocol messages carry sensitive data and require integrity, confidentiality and availability. Privacy is one of these security issues and has been addressed by proposing the use of pseudonyms for the medical data [22]. Embedding eHealth systems in a vehicular network is the focus of the WEHealth architecture [23]. WEHealth provides eHealth service for medical needs on roads and enhances security and privacy by the use of the NOTICE framework (a secure and privacy-aware architecture for the notification of traffic incidents). This infrastructure includes short-range communication capable sensor belts placed along the  
Figure 1: Vehicular-related wireless technologies comparison (adapted from [20]). road. The infrastructure in NOTICE uses embedded sensor belts in the road at regular intervals (e.g., every mile or so). Each belt is composed of a collection of pressure sensors and a few small transceivers. The pressure sensors in each belt allow every message to be associated with a physical vehicle passing over the belt, eliminating the need to uniquely identify vehicles in order to interact with them. The sensor belts do not communicate with each other directly and rely on passing cars to carry and forward a message between adjacent belts. Check station belts are authentication centers and pseudonyming proxies. They are placed on the roadside and attached to base stations to access the personal health record (PHR) server on the Internet. Medical queries or accident alarms can be disseminated through the system to provide health records of the patients. In addition to wireless communications with external sensor nodes on the road, the WEHealth platform assumes an underlying IPv4 Internet, and the server side (PHR server) is accessible through base transceivers. The platform presented in this paper does not rely on external interactions with sensors to carry the health-related data to the server and use a cellular long-range interface to provide the PHR server with patient health-related information. eCall [24] is a recent European standard that brings the possibility of dialing the EU emergency number (112) in case of a serious road accident automatically without the vehicle occupants' intervention. The European Commission adopted measures to ensure eCall will be available in new car models from 2015, although some manufacturer-specific prototypes are already deployed as proof-of-concept. Due to stringent delay requirements, eCall is to operate only on radio networks (some deployments already use GPRS cellular networks). The platform described in this paper involves non-time-critical eHealth applications; therefore, recorded data can be transported over IP (packet-switched domain).