An energy saving base station employing spatial modulation

In this paper, we evaluate the energy efficiency of a multi-antenna Base Station (BS) employing Spatial Modulation (SM). Taking advantage of the single Radio Frequency (RF) chain configuration of SM, we show that SM offers a significant total power reduction compared to other multi-RF chain Multiple-Input Multiple-Output (MIMO) architectures. For the same RF transmit power, we demonstrate that the total power saving of SM scales linearly with the number of RF chains required by other MIMO schemes. Furthermore, we clarify that for the same ergodic capacity, SM has a significant advantage in energy efficiency compared to the studied multi-RF chain MIMO configurations. In addition, for a number of transmit antennas larger than two, we establish that SM results in higher ergodic capacity than Space-Time Block-Coding (STBC), combined with significant power saving. For a BS with 8 transmit antenna, the achieved power saving of SM can reach up to almost 90%. Finally, based on simulation results, we demonstrate that the energy efficiency (bits/J) of the studied MIMO schemes exhibits a maximum as function of ergodic capacity, and it is further shown that this maximum is several times higher in SM compared to the studied state-of-the-art MIMO schemes.