Effect of smooth non-linear distortion on OFDM BER

Abstract

Non-linear distortion of OFDM signals can signifcantly increase the receiver BER. Currently, distortion analyses rely on simulation, not yielding insight into the problem, or apply to specifc non-linearities only. In this paper, general analytic results are presented on the erron resulting from distortion. The results are applicable to smooth non-linear distortion of an OFDM signal, which is the most common distortion. Simple analytical expressions are derived which allows a designer to determine the BER before performing simulations. Further, it is shown that the error on each OFDM subcarrier is approximately equally large.

Low cost characterization of RF transceivers through IQ data analysis

“…Each sub-carrier can carry independent data, increasing the robustness of the system. OFDM systems suffer from non-linearity of RF devices and quadrature imbalances [20] [19]. In order to ensure the fitness of the RF device, determination of these performance parameters is essential.…”

“…The details of this operation provides some insights about the quadrature imbalance calculation method that we propose. (20) ω k = 2πk∆ f (21) where IF F T {.} is the inverse FFT operation, N ST is the number of sub-carriers, C is the frequency domain complex coefficients that are coded with the input digital bit stream, C k is the k th frequency domain complex coefficient, and ∆ f is the frequency spacing of the sub-carriers, which is 312.5kHz in the IEEE 802.11a standard.…”