Throughput and energy efficiency of sensor networks with multiuser receivers and spatial diversity

Linear multiuser detectors and receive antenna arrays enhance the received signal-to-noise ratio, thereby improving both the throughput and the energy efficiency of sensor networks. We assume Rayleigh flat-fading and no uplink channel state information, and derive analytically the throughput of large sensor networks with linear multiuser detectors and spatial diversity, for both deterministic scheduling and slotted ALOHA multiple access. We introduce the notion of effective energy, and show that it can be minimized by judiciously choosing the number of simultaneous transmissions and the transmission power.