Energy Efficiency Scaling Law for MIMO Broadcasting Channels

This letter investigates the energy efficiency (EE) scaling law for the broadcasting channels (BC) with many users, in which the non-ideal transmit independent power consumption is taken into account. We first consider the single antenna case with K users, and derive that the EE scales as log2 lnK α when α > 0 and log2 K when α = 0, where α is the normalized transmit independent power. After that, we extend it to the general MIMO BC case with a M -antenna transmitter and K users each with N antennas. The scaling law becomes M log2 lnNK α when α > 0 and log2 NK when α = 0. Index Terms Energy efficiency, MIMO broadcasting channels, scaling law.