Adaptive Filter Predistorter for Memory Saleh Model

In a Broadband System, a High-Power Amplifier (HPA) is widely used for coverage expansion and availability due to its high efficiency. However, distortion has appeared on the input signal when the operation point exists almost in the saturation zone, which generates unwanted frequencies in adjacent channels and Inter-symbol interference (ISI). This channel interference is tightly controlled by the communications standard being used, and it must be reduced as much as possible. For this reason, several development techniques have been presented to enhance the broadband system performance one of them is Digital Pre-distorter (DPD). In this paper, a DPD has been investigated and evaluated to mitigate the Amplitude/Amplitude converter (AM/AM), Amplitude/Phase converter (AM/PM) and Memory using an adaptive filter with Least Mean Square (LMS) algorithm. This DPD is investigated on the Orthogonal Frequency Division Multiplexing (OFDM) signal with 16-QAM and 64-QAM to evaluate the performance using Matlab. The result shows high elimination to ISI effect. In addition, the AM/AM and the AM/PM effects have been eliminated worthy.