Energy Efficiency of Transmit Diversity Systems Under a Realistic Power Consumption Model

Abstract

Abstract-We compare the downlink energy efficiency of spatial diversity multiple transmit antenna schemes. We determine the minimum required transmit power for a given outage probability. Our analysis shows that antenna selection is in general the most energy efficient option as it requires a single radiofrequency chain. We also investigate the limiting distances up to which the antenna selection technique outperforms the transmit beamforming scheme for different numbers of transmit antennas.

Energy Efficiency-Spectral Efficiency Trade-Off of Transmit Antenna Selection

“…From Fig. 1 it can be seen that the proposed approximation in (28) for the TAS/MRC capacity gets closer to (21) when the number of antennas increases (different antenna setups are considered: 1×1, 2×2, 3×3 and 5×5). We also show that the approximation in (21) agrees very well with the exact capacity obtained by Monte Carlo simulations.…”

“…In Fig. 2 the accuracy of the TAS/MRC capacity approximation made in (28) is evaluated in terms of the energy efficiency upper bound, by comparing it to the EE upper bound obtained by numerically inverting the capacity expression in (21). It can be seen that, as the number of antennas increases, the proposed approximation improves.…”

“…Such technique achieves the same diversity order as other MIMO techniques employing all antennas at the transmitter [20], while decreases the energy consumption. As shown in [21], which compares TAS and transmit beamforming in terms of EE in a quasi-static fading scenario, TAS is a suboptimal strategy under the SE point of view, however, this fact is compensated by a higher EE. TAS is outperformed by beamforming only at considerably large distances (when the required transmit power prevails over the circuitry consumption).…”

“…However, if the transmit power dominates the circuit power consumption, the EE increases monotonically with the number of selected antennas, so that all antennas should be employed. Nevertheless, the trade-off between SE and EE is not considered neither by [21], nor by [22].…”

Energy and cost analysis of cellular networks under co-channel interference

“…The authors also consider temporal variations and the spatial distribution of traffic demands over large regions. Later, in [5], we employed the power consumption models of [4] to investigate the energy efficiency of wireless scenarios with multiple antennas at the base station and a single antenna at the mobile station.…”