Comparative study of polynomial based predistorters for LTE-radio over fiber applications

In this paper, we are comparative study of performance analysis of polynomial based predistorter technique with three different architectures viz. memory polynomial, envelope memory polynomial and hybrid envelope memory polynomial models for high order of nonlinearity (K = 7) and large memory length (Q = 3). The nonlinear distortion is a critical issue for radio over fiber link. The predistorter is one of the most important approaches to overcome the nonlinear distortion. In this paper the performance analysis of the two most prevailing predistorters (memory polynomial and envelope memory polynomial) have been compared with the performance of the model (hybrid envelop memory polynomial) developed by the author. The performance of different predistorter model are analyzed for input laser power ranging from −4dBm to 4dBm, input frequency for ∼0.55 GHz to ∼3.00 GHz and for different type of input signal like m-QAM, orthogonal frequency division multiplex, WiMax and LTE (long term evolution). The performance metrics are adjacent power ratio, error vector magnitude and normalized mean square error. The model have been tested for fiber length up to ∼50 km. Whole of the simulation work to compare the performance analysis has been carried out on OptiSystem v13.0 and MATLAB R20013a.