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MAC for Geographic Routing
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Since Geographic_routing can provide stateless routing service and dynamically adapt to the changing network topology, it has drawn a lot of attentions. However, because the explicit next hop is unknown when forwarding a data packet, usually geographic routing protocols can only work with broadcast MAC, which cannot effectively prevent collisions. As a result, geographic routing protocols cannot guarantee the packet delivery to the next hop. To this end, a cross-layer design solution is proposed
. Basically, a forwarder broadcasts a REQ packet, and then the qualified next hop selected by the integrated geographic routing protocol replies the REP packet. During the handshaking, the next hop is decided and the slot for data packet transmission is reserved. Different from the conventional handshaking, the reserved time slot could be after the reception of REP packet. With this technique, both hidden terminal problem and exposed terminal problems can be handled.
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