Identification for the GaN amplifier in OFDM communication system

An adaptive identification method is proposed to estimate the characteristics of GaN power amplifiers (GaNPA) in orthogonal frequency division multiplexing (OFDM) communication systems. The memory polynomial model (MPM) is adopted to describe the input-output relationship of unknown GaNPA in base-band and the RLS algorithm is used to estimate the MPM parameters of GaNPA in on-line manner. The MPM with odd-even orders is considered in choosing models. Furthermore, the orders and memory length of MPM are decided by the final prediction error (FPE). Finally, the stable and validate GaNPA model is achieved through comprehensively surveying phase and gain characteristics, and convergence of parameter estimation by numerical simulation.