بحوث سكوبس — اسامة جابر غايب القاضي

In this paper, we investigate blind channel estimation in cyclic, prefixed orthogonal frequency division multiplexing (OFDM) systems using precoding matrices. Many studies show how the performance of bit error rate (BER) and mean square error of channel estimation are impacted by using a circulant matrix as a precoding matrix. We investigate a new structure for the precoding matrix in which the first row is generated by an exponentially decreasing equation along with the Toeplitz function and deploying singular value decomposition (SVD) to generate the final precoder matrix. This type of SVD-based precoding matrix has been presented and simulated under various circumstances. The resulting precoding matrix is employed in two different OFDM systems to estimate the channel frequency response vector up to scalar ambiguity. The proof of the precoding matrix full rank property is presented, along with other criteria that help with the development of various precoding matrices. © 2024, Innovative Information Science and Technology Research Group. All rights reserved.

Using a new precoding matrix, a new method for blind channel estimation of OFDM systems with zero padding has been investigated. A single vector of the correlation matrix is employed to obtain the normalized estimated channel vector, and one pilot signal is used to resolve the scalar ambiguity. Two models of OFDM systems have been investigated, and their NMSE and BER results have been compared in various scenarios. In particular conditions, the new precoding matrix offers an advantage over the conventional circulant. To aid in the creation of novel precoding matrices, a proof of the full rank property is stated under some conditions. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (https://creativecommons.org/licenses/by/4.0/).

Using different precoding matrices, a new blind channel estimation in OFDM systems with cyclic prefix is presented in this paper. The proposed method employs one column of the correlation matrix directly, unlike the traditional precoding techniques where the elements of precoding matrix is been removed. Results show the impact of this method specially when using the type of precoding matrices which include the circulant property in its design. Since channel order estimation is an important task in blind methods, a new and simple algorithm is also investigated with no additional complexity been added to the system. A proof of diagonalizability property is mentioned which can be implemented for other investigations concerning this type of matrices. © WFCES 2023