Modeling and Analysis of Energy Consumption for MIMO Systems

In this paper, we provide a comprehensive study and comparison of the energy consumption and bit-rate of multiple-input multiple-output (MIMO) wireless devices using multilevel quadrature amplitude modulation (MQAM). Both spatial diversity and spatial multiplexing (SM) are examined and compared under the assumption of perfect channel state information (CSI) at the transmitter. The transmit energy is derived under a target probability of error p(eb) at the receiver. The transmit energy and transceiver circuit energy are then utilized to study energy tradeoffs for MIMO diversity and SM. We observe that the amount of energy savings for diversity orders two and three is steeper than that of higher diversity orders. On the other hand, SM provides a linear increase in the overall bit rate along with receiver diversity due to maximum likelihood detection. Using these results, we create a diversity-SM tradeoff for energy consumption vs. bit-rate. Using these results our proposed scheme can save around 4 dB in energy consumption while achieving the highest bit rate after full SM at p(eb) = 10(-3)