In the study of the joint estimation of time-frequency signature and direction of arrival (DOA) for multicomponent chirp signals, an estimation method based on spatial time-frequency distributions (STFDs) is proposed in this paper. Firstly, array signal model for multicomponent chirp signals is presented and then array processing is applied in time-frequency analysis to mitigate cross-terms. Ac...

This paper presents a novel channel estimation and compensation technique, combining fading estimation and frequency offset estimation, for preamble-assisted differentially encoded amplitudeand phase-shift keying (DAPSK) transmission in the digital mobile radio system. The received preamble symbols are used to estimate the combined distortions caused by multipath fading and frequency offset. Th...

Abstract Coherent rake reception of direct sequence code division multiple access (DS-CDMA) signals requires accurate channel estimation in a frequency-selective fading channel. In this paper, we study the channel estimation method using FFT/IFFT for coherent DS-CDMA mobile radio using the code-multiplexed pilot structure. This channel estimation method can provide a good tracking capability ag...

~~~. ~~~~~~ ~ . . ~ ~ ~ ~ ~ ~ ~ . ~ ~ ~ ~ ~ ~ . . near the Cram&-Rao bound in the variance of estimation errors: Simulations of several estimation algorithms in a estimation. Also the complex data of the pilot subcarriers, instead of their phases, are averaged. However, these multipath fading channel show'that this algorithm provides the most accurate estimation in both the carrier frequency of...

This paper addresses the problem of the contradiction between estimation accuracy and estimation range of the frequency estimation in OFDM. According to the packet structure of IEEE Standard 802.11a and the characters of short training symbols, a new frequency offset estimation algorithm is presented. A two stages strategy based on auto-correlation algorithm is used to solve the contradiction b...

In this paper, we firstly construct a wide-band undersampling array, then present a novel frequency and direction of arrival (DOA) estimation method for a very wide frequency band (2-18GHz). Choosing a set of appropriate sampling frequencies and antenna spacing, the method can provide unambiguous frequency and DOA estimation under the sub-Nyquist spatio-temporal sampling. The proposed method ca...

Direct conversion receivers in orthogonal frequency division multiplexing (OFDM) systems suffer from direct current (DC) offset, frequency offset, and IQ imbalance. We have proposed an IQ imbalance estimation scheme in the presence of DC offset and frequency offset, which uses preamble signals in the time domain. In this scheme, the DC offset is eliminated by a differential filter. However, the...

In this paper, average frequency correlation and rootmean-squared (rms) delay spread estimation for wireless communication systems are described. A practical algorithm for averaged channel frequency correlation estimation, which can be used for measuring frequency selectivity, is given. Average rms delay spread of the channel is obtained directly from the channel frequency correlation estimate ...

Carrier Frequency Offset Estimation for Orthogonal FrequencyDivision Multiplexing Systems Xiang Nian Zeng, Ph.D. Concordia University, 2008 Orthogonal frequency division multiplexing (OFDM) is an attractive modulation scheme used in wideband communications because it essentially transforms the frequency selective channel into a flat fading channel. Furthermore, the combination of multiple-input...