With the popularity of smart phones and tablets, people make intensive use of these devices on public transport. It is thus interesting to deploy mobile relays in public transportation with the aim of offering high-quality services. In LTE Rel 10 fixed relays are specified. Although mobile relays have been considered by 3GPP, no protocol stack is specified yet. In this paper, we propose to keep the same protocol stack as for fixed relays but introduce the concept of global tunnel, which gathers several tunnels. We analyze the main signaling procedures and show that the proposed solution dramatically reduces the number of messages that each network node should process.