Energy-Efficient Relay Assignment and Power Control in Multi-User and Multi-Relay Networks

We consider a multiuser multirelay network where each source communicates with its destination via an assigned relay. To ensure fairness among the users, the minimum of the users’ energy efficiencies (in bit-per-Joule) is jointly maximized with respect to the relay assignment and transmit power of both source and relay nodes. The resulting algorithm is provably convergent, requires limited complexity, and significantly outperforms the baseline scenario in which no joint optimization of transmit powers and relay assignment is performed.