Energy-Efficient Design of MIMO Processing for Two-Tier Wireless Sensor Networks

This letter studies the energy-efficient design of linear processing strategies for a wireless sensor network consisting of two-tier wireless links. In the system, a set of single-antenna sensor nodes sense the information of interest and report the sensed data to a fusion center (FC) through a set of relay nodes. It is assumed that the FC and relay nodes are equipped with multiple antennas and the sensors-to-relays and the relays-to-FC channels are separated in frequency or time domain. Motivated by the observation that remote sensors tend to be equipped with limited battery life, this letter tackles the problem of maximizing the minimum of the energy efficiency metrics of the sensors while satisfying the per-sensor and per-relay transmit power constraints under compress-and-forward relaying strategy at the relays. Numerical results validate the advantages of the proposed energy-efficient design as compared to the conventional spectrally efficient scheme.