Approximate Characterization of Capacity in Gaussian Relay Networks

The authors present an achievable rate for general Gaussian relay networks. They show that the achievable rate is within a constant number of bits from the information-theoretic cut-set upper bound on the capacity of these networks. This constant depends on the topology of the network, but not the values of the channel gains. Therefore, they uniformly characterize the capacity of Gaussian relay networks within a constant number of bits, for all channel parameters. Characterizing the capacity of wireless relay networks has been a challenging problem over the past couple of decades. Although, many communication schemes have been developed the capacity of even the simplest Gaussian relay network: single source, single destination, single relay, is still unknown.