Multiple amplifier separation structure for OFDM modulation

In recent years, the OFDM (Orthogonal Frequency Division Multiplexing) modulation method is widely used in high-speed communication systems such as terrestrial digital broadcasting systems and high-speed wireless communication systems. However, the amplitude of the OFDM signal shows large fluctuation. Then an OFDM system requires high linearity, especially in its high power amplifier (HPA). As a result of HPA back-off operation, its efficiency deteriorates, and then its power consumption increases. In this paper, we propose a spatially superposed OFDM transmission system with multiple amplifiers and a spatial power combining technology. We carried out the simulation of the total power consumption and transmission characteristics. From this investigation, it is expected that the proposed system can reduce the power consumption by about 44%, compared with a conventional system with one HPA.