Multi-band Digital Predistortion in IoT System with Co-prime Sampling Technique

With the rapid development of Internet of Things(IoT), concurrent multi-band digital predistortion(DPD) forthe nonlinear power amplifier become an effective way to save spectrum and power resources. Traditional DPD method for multi-band increases the number of feedback loops to sample bands at different carrier frequencies, greatly increasing the hardware cost. To simplify the IoT system structure, a single feedbackpath with an under-sampling technique for multi-band digital predistortion has been proposed, but linear performance will deteriorate if too much peak power information is lost after under-sampling. To solve those problems, a novel architecture for tri-band digital predistortion is proposed. In the single feedback structure, twosampling signals are obtained by using two time synchronization ADCs with co-prime under-sampling factors. Theoriginal signals can be reconstructed with recover algorithm to calculate the tri-band predistortion coefficients. The proposed method performs well both in the aspect of hardware complexity and linearization capability. The experimental results show that the proposed method still achieves sufficient performance at a very small sampling rate.