Mitigating NLD for Wireless Networks: Effect of Nonlinear Power Amplifiers on Future Wireless Communication Networks

Efficient utilization of limited bandwidth with high-data-rate transmission while serving a large number of users is a prime requirement for present and future wireless communication systems. To meet this rising demand, orthogonal frequency-division multiplexing (OFDM) and cooperative communication have emerged as promising solutions due to their robustness in severely degraded channel conditions, link reliability, and spectral efficiency. Both OFDM and cooperative systems have challenged RF front-end specifications such as bandwidth and power-efficiency requirements for end users as well as for the base station due to the high peak-to-average power ratio (PAPR). In present and future communication systems, the power amplifier (PA) is a key component at the transmitter. To obtain maximum power efficiency, the PA is operated near its saturation point, which leads to nonlinear distortion (NLD), which is further exaggerated due to the high PAPR of the input signal. This NLD is expected to increase in future fifth-generation (5G) communication networks, due to the use of large bandwidth at millimeter-wave (mmW) frequencies.