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In this paper, a new approach of blind estimation of subcarrier number based on multiple signal classification (MUSIC) algorithm is proposed for MB-OFDM ultra-wide band (UWB) communications system. The proposed eigenvalue-construct method only using signal autocorrelation of orthogonal frequency-division multiplexing (OFDM) symbols estimates the number of subcarriers. The computer simulations show...
This paper proposes a new I/Q imbalance estimation algorithm for multiband orthogonal frequency division multiplexing (MB-OFDM) based ultra-wideband (UWB) systems. The proposed algorithm is highly effective for the UWB channels with strong frequency selectivity in the presence of carrier frequency offset (CFO). In order to estimate I/Q imbalance, the 2nd-order moments of received signal are analyzed,...
In WLAN receivers, a direct conversion architecture has been implemented in recent years. Though this architecture reduces cost and power consumption, it may suffer from direct current (DC) offset and frequency offset. To reduce the effect of DC offset, a frequency offset estimation scheme with a differential filter for orthogonal frequency division multiplexing (OFDM) direct conversion receivers...
In the paper, we propose a conditionally biased linear estimator to estimate a deterministic vector h subjected to a linear transformation M and corrupted by zero-mean additive white Gaussian noise, w. We begin by drawing inspiration from the rank shaping idea of the Rank Shaped Least Squares (RSLS) estimator. We then incorporate the estimator into the Covariance Shaping Least Squares (CSLS) framework,...
A fine time tracking system is presented for orthogonal frequency division multiplexing (OFDM) systems working in multipath fading channels. Due to the channel variability, coarse timing is the most common sampling synchronization level performed in these environments. However, in case of slow time variant channels, fine time tracking can help in some way to the channel equalization, improving the...
Considering orthogonal frequency division multiplexing (OFDM) transmissions, we derive analytical expressions for the Cramer-Rao bounds for the subcarrier signal-to-noise ratio (SNR) estimates. The channel coefficients of the different subcarriers are assumed to be constant over the observation interval and the received signal is assumed to be corrupted by additive white Gaussian noise (AWGN). We...
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