HPA nonlinearities mitigation by joint predistorter and constellation rotation using MIMO communication systems

Nonlinearities in wireless communication channels foil the performance of the communication systems either at the transmitter or receiver end. This paper explains the concept of the transmitter-side nonlinearities that are induced by the High Power Amplifiers (HPA), the final stage at the transmitter side of the communication system. HPA nonlinearities create in-band and out-of-band distortions in wireless communication systems. The in-band distortion results in the degradation of overall performance of Bit Error Rate (BER) and the capacity of the mobile operations. On the other hand, out-of-band distortion creates the spectral broadening effects that degrade the performance of other operators usually operate in the near bands. This paper presents a novel method for the mitigation of HPA nonlinearities by joint predistorter and constellation rotation in Multiple-Input Multiple-Output (MIMO) wireless communication systems. The results reveal that the joint nonlinearity compensation technique in MIMO communications system enhances the overall error rate performance of the system. Furthermore to exploit the benefits of proposed technique; Symbol Error Rate (SER) curves for the MIMO multiplexing and Alamouti Space Time Block Codes (STBC) are presented with improvements in their signal to noise ratio.