Abstract
Frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion can replace the conventional rake combining to significantly improve the bit error rate (BER) performance in a frequency-selective fading channel. MMSE-FDE requires an accurate estimate of the channel transfer function and the signal-to-noise power ratio (SNR). Direct application of pilot-assisted channel estimation (CE) degrades the BER performance, since the frequency spectrum of the pilot chip sequence is not constant over the spreading bandwidth. In this paper, we propose a pilot-assisted decision feedback frequency-domain MMSE-CE. The BER performance with the proposed pilot-assisted MMSE-CE in a frequency-selective Rayleigh fading channel is evaluated by computer simulation. It is shown that MMSE-CE always gives a good BER performance irrespective of the choice of the pilot chip sequence and shows a high tracking ability against fading. For a spreading factor SF of 16, the Eb/N0 degradation for BER=10-4 with MMSE-CE from the ideal CE case is as small as 0.9 dB (including an Eb/N 0 loss of 0.28 dB due to the pilot insertion).
Original language | English |
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Pages (from-to) | 1746-1753 |
Number of pages | 8 |
Journal | IEICE Transactions on Communications |
Volume | E90-B |
Issue number | 7 |
DOIs | |
Publication status | Published - 2007 Jul |
Keywords
- Channel estimation
- DS-CDMA
- Frequency-domain equalization
- MMSE criterion
ASJC Scopus subject areas
- Software
- Computer Networks and Communications
- Electrical and Electronic Engineering