CRANE Project Wireless Networking Demonstration

a) Single-hop transmissionb) Multi-hop transmission

with a mobile relay node

Direct transmission requires high power to maintain the connectivity of a wireless link. Power increases at least quadratically with the increase of transmission distance.

4dB

Signal spectrum at receiver

Mobile relay enhances the connectivity of the sensor network with the same power consumption1, or alternatively, keeps the connectivity of the network with less resource consumption.

Signal spectrum at receiver

12.5dB

1 For fair comparison, the power consumed in direct transmission is twice of the power consumed in each hop of a two-hop link.

Received signal spectrums with different relay locations (distance of two locations around λ/2) of the mobile relay.Multipath fading in wireless

channels

The mobile relay further takes the advantage of spatial diversity of multipath fading in wireless channels. Compared to the relay at fixed location, transmission reliability can further be increased with slight movement of a relay mote.