Network Mobility Management in the ITS Context: Protocols for Managing Vehicle-to-Infrastructure Communications

Introduction

The provision of internet services while traveling is a flourishing market that should be covered by means of emerging mobile computing and communication techniques. This scenario presents specific challenges that current communication architectures do not cover. Indeed, Intelligent Transportation System (ITS) standardization bodies are currently defining a dedicated communication architecture that satisfies the scenario necessities and the increasing demands.

ITS communication standards are being designed to support multiple classes of applications including those that assist in vehicle operation and internet-based applications (European Telecommunications Standardization Institute [ETSI], 2010). In fact, internet-based applications are considered to be beneficial for safety, and fundamental for non-safety purposes (Baldessari, Festag, & Lenardi, 2007b). Furthermore, the ITS communication architecture should not only focus on the vehicle communication needs, but also in the demands of users onboard. On the other hand, it is assumed that an ITS-compliant vehicle is a moving network, where a set of nodes should obtain anytime-anywhere connectivity to the internet through one or more Mobile Routers (MR). Figure 1 shows the network mobility scenario.

Figure 1.

Network mobility management scenario

With the aim of obtaining anytime-anywhere connectivity to the internet, the mobility of the vehicle has to be managed. Two approaches for managing the mobility in this context can be distinguished:

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  Individual management or host mobility management. The mobility of each node located in the vehicle is managed individually. Therefore, this approach requires managing one by one the handovers of each node located inside the mobile network in order to be them reachable from the internet. In this approach the Mobile Routers has basically routing functions. The most outstanding protocol to manage host mobility are MIPv6 (Johnson, Perkins, & Arkko, 2004) and its improvements, HMIPv6 (Soliman, Castellucia, ElMalki, & Bellier, 2008), FMIPv6 (Koodli, 2009) or PMIPv6 (Gundavelli, Devarapalli, Chowdhury, & Patial, 2008).

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  Management as a whole or network mobility management. The mobility of the entire moving network is managed jointly through a single entity, the MR. This approach has the advantage of reducing the signaling overhead in the wireless access link and consequently, less power is consumed. In addition, when the MR performs a handover all the nodes inside the mobile network can access the outside network immediately. NEtwork MObility (NEMO) Basic Support (Devarapalli, Wakikawa, Petrescu, & Thubert, 2005) which is an extension of MIPv6 is the de facto protocol for managing network mobility.

Figure 2 shows both network mobility management approaches.

Figure 2.

Approach for managing the mobility of entire networks: Individually or as a whole

The key difference between the aforementioned approaches is the manageability, which is tightly related to the signaling exchange required by the mobility management solution. In addition, it is worth pointing that signaling is one of the major design considerations for mobility management protocols, as it is directly related to the useful throughput for user data communications and consequently the performance of the services.