Comparison of time domain and frequency domain equalization for HSDPA channel

Abstract

In this paper we compare the time domain equalization (TDE) and frequency domain equalization (FDE) for high speed downlink packet access HSDPA channel profiles [1]. Linear minimum mean squared error (LMMSE) equalizers for FDE [2] and TDE [3–4] are implemented. We use the overlap and save technique for frequency domain filtering operation to alleviate the problem of circular convolution. The simulation results show that FDE based on a 256 point complex Fast Fourier Transform/Inverse Fast Fourier Transform (FFT/IFFT) is well suited for HSDPA receiver. For TDE, 40 taps equalizer is selected as in terms of gate count the complexity of a 40 taps TDE implementation and the proposed 256 point FFT FDE implementation is estimated to be comparable. Our results show that HSDPA receivers with FDE are more efficient with lesser complexity as compare to receivers with TDE.