Energy-efficient cooperative beamforming using timer based relay subset selection

Energy efficiency has become a crucial performance metric in wireless communications due to the increasing energy consumption resulting from increasingly widely deployed wireless communication systems and devices. We propose a timer based relay selection scheme that selects a subset of available relays to perform cooperative beamforming for data transmission in an energy-efficient way. We analyse the resulting energy efficiency taking into account the additional energy consumed by the overhead required to obtain channel state information, to select relay subset and to perform cooperative beamforming. We also study the impact of the number of cooperating relays, their location and different data packet length on energy efficiency. The simulation results show that for relays located close to the source the proposed scheme is more energy efficient than direct communication, conventional best relay selection, all relay selection and an existing cooperative relaying scheme. Moreover, through simulation it is revealed that increasing data packet length leads to significant energy savings.