Energy Efficient Massive MIMO IoT Network: A Power and MSE Constrained Approach

This paper considers massive multiple-input multiple-output (MIMO) Internet of Things (IoT) networks where each sensor is equipped with a single antenna, while the fusion center (FC) is equipped with a massive array of antennas. Each sensor takes the linear noisy observation of the underlying unknown random quantity, pre-processes it, and then transmits its precoded observation to the FC over a fading wireless channel for efficient post-processing. Since these sensors are battery-operated tiny devices, energy efficiency (EE) becomes such a critical factor to optimize, while individual mean square error (MSE)-based quality of service (QoS) constraints ensures an efficient estimation of the random quantities at the FC. Quadratic transform theory is used to solve the resulting non-convex EE maximization problem, and the first-order Taylor series approximation is used to linearize the non-convex quantities. Our numerical results corroborate the analytical findings of this work.