FIXED-POINT REFINEMENT OF OFDM-BASED ADAPTIVE EQUALIZERS: AN HEURISTIC APPROACH (ThuAmPO2)

Author(s) : Gabriel Caffarena (Dep. Ingeniería Electrónica, Universidad Politécnica de Madrid, Spain) Angel Fernández (Dep. Ingeniería Electrónica, Universidad Politécnica de Madrid, Spain) Carlos Carreras (Dep. Ingeniería Electrónica, Universidad Politécnica de Madrid, Spain) Octavio Nieto-Taladriz (Dep. Ingeniería Electrónica, Universidad Politécnica de Madrid, Spain)

Abstract : In this paper we address the quantization of adaptive equalizers for OFDM-based WLAN. Traditional simulation-based approaches require extremely long times to quantize complex systems. We have tackled this issue threefold: i) generating a minimization wordlength procedure tuned for adaptive equalizers; ii) providing a quantization evaluation criterion that allows fast Monte-Carlo simulations with high relative errors; and iii) simulating only a subset of subcarriers to extract quantization information. One of the main results is that running several single-subcarrier simulations is possible to achieve acceptable results in simulation time and performance degradation compared to the simulation of complete OFDM symbols. We use as a practical example a 220 Mbps OFDM RLS equalizer combined with ABL pre-equalization.

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