All existing training signal designs for channel estimation in OFDM systems assume no frequency offsets. In practice, frequency offset is unavoidable and seriously degrades the performance of OFDM systems. In this paper, we address the problem of designing optimal training signals for SISO OFDM channel estimation in the presence of frequency offsets. First, we present optimal training signals f...

Wireless communication system is prone to distortions and noise. The system utilizes many techniques to minimize the distortions and noise effects. The use of channel estimators is one of the many techniques and has decent success. The channel estimation is important process in modern wireless communication as it provides the channel state information. Thus it is important to get correct channe...

Least mean square (LMS)-based adaptive algorithms have attracted much attention due to their low computational complexity and reliable recovery capability. To exploit the channel sparsity, LMS-based adaptive sparse channel estimation methods have been proposed based on different sparse penalties, such as l1-norm LMS or zeroattracting LMS (ZA-LMS), reweighted ZA-LMS, and lp-norm LMS. However, th...

We consider a blind estimation of the vector channel for systems with receive diversity. The objective of this paper is to reduce the complexity of the conventional subspace-based method in vector channel estimation. A reduced-complexity estimation scheme is proposed, which is based on selecting a column of the covariance matrix of the received signal vectors. The complexity and performance of ...

Orthogonal frequency-division-multiplexing (OFDM) has been actively pursued in underwater acoustic communications. However, OFDM is extremely sensitive to carrier frequency offset (CFO) which cause significant problems. The utilization and performance of traditional channel estimation are poor. Although underwater acoustic communication was recently the focus of research, literatures on joint i...

Pilot-aided adaptive prediction channel estimation is proposed for coherent detection in a frequencynonselective fading channel. It is an extension of the conventional weighted multi-slot averaging (WMSA) channel estimation and consists of 3 steps. A block of Np pilot symbols is periodically transmitted, each pilot block being followed by Nd data symbols to form a data slot. In the first step, ...

In current common channel estimation schemes for MIMO OFDM systems, channel state information is usually achieved by estimating channels according to frequency domain pilot sequences. However, when the length of MIMO OFDM symbols is larger than that of wireless channel delay, there are two intractable issues in the case of cellular fast fading channel scenarios with large numbers of users, i.e....

In these days Wireless Broadband Technologies allow simultaneous delivery of voice, data and video over fixed or mobile platforms. WiMax 4G, Orthogonal Frequency Division Multiplexing (OFDM), Interleave Orthogonal Frequency Division Multiplexing (IOFDM) are some of the emerging broadband technologies. The paper is divided into two parts channel estimation and channel response. In the channel es...

Orthogonal frequency division multiplexing (OFDM) is a technique which are used in the next-generation wireless communication. Channel estimation in the OFDM technique is one of the big challenges, ever since high-resolution channel estimation can significantly improve the equalization at the receiver and consequently enhance the communication performances. Channel computation using superimpose...

We present space-time methods for channel estimation in the downlink of a UMTS/TDD system. The channels associated to all base stations near the mobile receiver are estimated by a multiuser, multi-antenna technique. We develop a minimum mean-square error (MMSE) channel estimator that incorporates midamble detection/estimation and least-squares channel estimation as preparatory stages. Combinati...