Time-domain envelope measurement technique with application to wideband power amplifier modeling

Modelling and inverting complex-valued wiener systems

“…The operation of HPAs in wireless systems may introduce serious memory effects and nonlinear distortions [12], [23], [24], causing intersymbol interference and adjacent channel interference that degrade the system's achievable bit error rate (BER) performance. The problem becomes particularly acute for high bandwidth-efficiency quadrature amplitude modulation (QAM) systems [25].…”

An efficient compensation of TWTA's nonlinear distortion in wideband OFDM systems

“…illustrates the TWTA modeling in stages 1 and 2. Since TWTA's nonlinear distortion can be considered a Wiener structure in wideband systems [2], TWTA consists of MND preceded by memory effects in Fig. 1.…”

“…For this, only the input signal with small amplitude x small (n) is selected as depicted in Fig. 1(a) since the input signal with small amplitude usually operates in the linear region of TWTA [2], [4]. For the operation in the linear region, Fig.…”

“…Like most types of HPA's, TWTA exhibits memory effects as well as MND in wideband systems. Especially, TWTA's such characteristics can be modeled as Wiener structure (which has memoryless nonlinear subsystems preceded by linear subsystems) [2]. However, the Wiener structure modeling for TWTA exhibits extremely slow convergence in OFDM systems [3].…”

“…12, pp. 2531-2540, Dec. 1998 H. W. Kang, Y. S. Cho, and D. H. Youn, "On compensating nonlinear distortion of an OFDM system using an efficient adaptive predistorter," IEEE Trans. Commun., vol.…”