An achievable rate per unit energy for multiple relay networks

In this paper, an achievable rate per unit energy is obtained for a multiple relay Gaussian network, where transmissions are over orthogonal channels. A single source transmits to a single destination helped by multiple-hop relay transmissions. A regenerative relaying function is employed at the relays that, instead of trying to decode the source transmitted message, facilitates the transmission between a previous relay and the destination. For this scenario, the energy allocation and routing solution are shown to be suitable for a distributed implementation.