Energy Efficiency Improvement of Coded OFDM Systems Based on PAPR Reduction

For long-distance wireless communications, a power amplifier (PA) is one of the most power-hungry devices at a transmitter. In many recent wireless standards that pursue higher spectral efficiency, signaling techniques with a high peak-to-average power ratio (PAPR) such as orthogonal frequency-division multiplexing (OFDM) have been adopted, but they typically end up with poor PA efficiency. A variety of PAPR reduction approaches have been thus proposed in literature to improve the power efficiency from the physical-layer perspective. In this paper, we investigate how much improvement in terms of the power efficiency can be achieved by such PAPR reduction techniques for OFDM signaling, and we evaluate the achievable coded frame error rate (FER) from a viewpoint of system-level design. It reveals that, in addition to the improvement of the PA efficiency, carefully designed PAPR reduction techniques in fact have a potential of reducing the required signal-to-noise power ratio at a receiver for achieving a given target FER and reducing the duty cycle of a transmitter circuit for a given target information rate. This in turn helps in reducing the total energy consumed at the transmitter of mobile terminals and thus leads to greener communication systems.