Upper Bounds on the Ergodic and Outage Capacities of Relay Networks Using UWB Links

We derive, evaluate, and discuss upper bounds on ergodic and outage capacities for a three-node relay network. The considered relay network has ultra-wideband (UWB) radio channels between the source, destination, and relay nodes. The derived bounds indicate that ergodic and outage capacities of the considered UWB-linked network increase up to 300% when a relay between the source and the destination is used. Furthermore, the bounds indicate that there is an optimum position for the relay node between the source and the destination, where ergodic capacity is maximized. Our numerical results shows that for the non-line-of-sight (NLOS) scenario, with the same signal to noise ratio on all links, the optimum position for the relay node is close to the center of source and destination.