Stefan A. Fechtel

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Orthogonal frequency-division multiplexing (OFDM) is the technique of choice in digital broad-band applications that must cope with highly dispersive transmission media at low receiver implementation cost. In this paper, we focus on the inner OFDM receiver and its functions necessary to demodulate the received signal and deliver soft information to the(More)
This paper details on the design of OFDM receivers. Special attention is paid to the OFDM-specific receiver functions necessary to demodulate the received signal and deliver soft information to the outer receiver for decoding. In Part I of the paper, the effects of nonideal transmission conditions have been thoroughly analyzed. To show the impact of the(More)
In the presented paper a new method of estimating and correcting transmitter-caused I/Q imbalance in a transmission system based on the WLAN standard IEEE802.11a is proposed. The estimation process consists of an initial estimation followed by an iterative tracking of the I/Q imbalance parameters. Additionally, with the modified preamble structure presented(More)
In the presented paper, the principle of frequency domain channel estimation for wireless OFDM systems will be shown. A well known noise reduction technique will be adapted to HIPERLAN/2 and IEEE802.11a standards, and its positive effects will be demonstrated by simulation results. Channel tracking has not been considered by the WLAN standards named above,(More)
Orthogonal Frequency-Division Multiplexing (OFDM) is essentially identical to coded OFDM (COFDM) and discrete multi-tone modulation (DMT). It is a frequency-division multiplexing (FDM) scheme, which is used as a digital multicarrier modulation method. The paper is aimed at analyzing the BER performance of the MIMO (Multi-Input MultiOutput) OFDM system for(More)