The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A novel noise whitening technique of blind subspace channel estimations is proposed for cyclic prefixing multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. A fast convergence subspace channel estimation for cyclic prefixed MIMO-OFDM systems was presented in [1] where the repetition index was used to increase the number of equivalent received signals. However,...
A base station (BS) in an LTE cellular network, transmits primary synchronization signal (PSS) in every frame to facilitate synchronization. PSS are derived from Zadoff-Chu (ZC) sequences. User equipment (UE) determines physical layer identity and frame timing of BS transmissions, by PSS acquisition. The techniques to detect PSS are typically based on cross-correlating the received signal with local...
In this paper, a novel narrowband interference (NBI) cancellation scheme based on structured compressive sensing (SCS) for dependable vehicular communications systems is proposed. The temporal joint correlation of the repeated training sequences in the preamble are exploited by SCS-based differential measuring (SCS-DM) to acquire the joint measurements matrix of the NBI. Using the proposed structured...
Orthogonal Frequency Division Multiplexing (OFDM) systems are very sensitive to symbol timing and frequency offsets. Therefore, it is very important to achieve a high precision time and frequency synchronization. With the absence of pilot symbols, blind synchronization algorithms using different metric functions or statistics of the received signal can be used. In this paper, a new blind symbol timing...
In free-viewpoint TV system considering hybrid transmission through heterogeneous networks, our proposed scheme using Zadoff-Chu sequence can improve synchronization performance of this system.
Most of the wireless systems such as the long term evolution (LTE) adopt a pilot symbol-aided channel estimation approach for data detection purposes. In this technique, some of the transmission resources are allocated to common pilot signals which constitute a significant overhead in current standards. This can be traced to the worst-case design approach adopted in these systems where the pilot spacing...
A new asymptotically optimal algorithm for OFDM-signal reception under AWGN and OFDM interference shifted in frequency is proposed. It outperforms the known algorithms in terms of complexity and has no limitations on the number of subcarriers in useful and interfering signals. The proposed optimal reception algorithm can be used for SEFDM signal reception when two components in it are present: the...
This paper proposes a computationally efficient, linear minimum mean square error (MMSE) channel estimation algorithm based on KL series expansion for OFDM systems. Based on such expansion, no matrix inversion is required in the proposed MMSE estimator. Moreover, truncation in the linear expansion of channel is achieved by exploiting the optimal truncation property of the KL expansion resulting in...
Spatial Multiplexing (SM) is an effective means for enhancing the transmission data rate in Multiple-Input Multiple-Output (MIMO) systems, particularly when used in combination with precoding. Precoding based on the knowledge of the slow-varying statistics of the channel exploits this information at the transmitter to combat the effect of fading in SM systems. Moreover, this technique requires little...
In this paper, we propose a robust timing and frequency synchronization algorithm for the orthogonal frequency division multiplexing (OFDM) systems. The algorithm we proposed can achieve accurate timing and frequency synchronization in time-domain by using the preamble consisting of only one training symbol based on constant amplitude zero autocorrelation (CAZAC) sequence and a new weighting factor...
Narrowband power line communications (NB-PLC) operating in the 3–500 kHz frequency band is proposed as a solution to support the emerging Smart Grid applications that aim to optimize the efficiency and reliability of the power grids. PLC is attractive for Smart Grid communications as it can be deployed over the existing power grids without any additional infrastructure. However, PLC suffers from impulsive...
We proposed a new method for accurate timing estimation in OFDM systems. A conventional timing estimation based on autocorrelation and crosscorrelation experience performance degradation due to multipath channel distortion. The proposed method is developed based on normalized 3rd-order central moment for symmetric correlator. Based on these 3rd-order central moment, a binary hypothesis testing problem...
In this paper a novel method for synchronization and cell search in 3GPP LTE downlink (DL) system has been proposed. This method performs the symbol timing and physical-layer cell identity estimation in frequency domain with less complexity, utilizing the frequency domain properties of the primary and secondary synchronization signals. The primary synchronization signals have good orthogonal and frequency...
In this paper, we propose a Double-Dwell (DD) Carrier Frequency Offset (CFO) estimation algorithm for Orthogonal Frequency Division Multiplexing (OFDM) signals. The proposed scheme is based on a two-stage correlation operation to provide an initial coarse estimate of the carrier offset followed by a much finer search to improve the accuracy. The search step size and search window are varied to optimize...
For orthogonal frequency division multiplexing (OFDM) receivers, the mutual orthogonality of the subcarriers is preserved only if the estimated symbol timing error lies in the lock-in region. Conventionally, a bias is added to the coarse symbol time offset (STO) estimate to move the symbol timing error into the lock-in region, thus increasing the lock-in probability. Upon review of the literature,...
A novel preamble structure is proposed for a timing estimation for orthogonal frequency division multiplexing (OFDM) systems such as the IEEE 802.11 and the IEEE 802.15.4g/4m. The boundary estimation becomes easy because of the outstanding correlation property between the short training sequence (STS) and the proposed long training sequence (LTS). The proposed method can be applied to OFDM systems...
Correlation difference timing scheme (CDTS) algorithm based on cross-correlation difference and correlation summation peak protection is proposed to address the critical issue of symbol timing synchronization for MB-OFDM based UWB systems. The two step synchronization scheme attempts to locate the start sample of the frame sequence (FS) by firstly calculating the cross correlation difference of received...
MIMO-OFDM systems have the ability to maintain high performance even in sophisticated channel conditions. But to ensure that the system remains robust to multipath channel conditions proper timing and frequency synchronization is essential. The multipath fading channels and noise in the signal makes timing synchronization difficult to implement. In this paper, a timing synchronization technique using...
This paper presents an intact scheme of timing synchronization for Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) Ultra Wide Band (UWB) systems. Frame detection and coarse timing are implemented with the Maximum Correlation (MC) method based on the first-band information of the preamble. Fine timing is achieved with the Minimum Energy Ratio (MER) method based on the information of...
This paper aims at contributing to find out the best pulse shaping technique to reduce peak to average power ratio (PAPR) for OFDM system efficiently. At first different narrowband pulses (Sine, Tukey window and Kaiser window) as well as broadband pulses (Raised cosine and Square root raised cosine pulse) have been employed in the transmitter section. In order to carry out the performance analysis,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.