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 multi-pair two-way relaying scenario with multi-antenna nodes is considered. The bidirectional communications between the nodes are supported by an intermediate non-regenerative multi-antenna relay station. It is assumed that the nodes can subtract the back-propagated self-interference. In such a scenario, the required data rates for each direction of transmission are typically different which is...
This paper deals with different techniques for linear equalization of multipath channels with imperfect channel estimation (CE). We develop a unified framework based on Krylov subspace expansion, which allows us to compare the performance of the conjugate gradient (CG) method, diagonal loading (DL), and a hybrid scheme. Our analysis shows that the DL method generally outperforms its alternatives,...
In this paper, we consider power-controlled wireless multiantenna sensor networks with interference and study the general trade-off between energy consumption and quality-of-service expressed in terms of the signal-to-interference ratio (SIR). First, we develop a model for the energy consumption of multiantenna nodes (i.e., energy consumption for transmission and hardware) and then study the trade-off...
A robust and reduced-complexity H-infinity (H-inf) channel estimator for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is addressed. The proposed estimator is realized by taking the following procedures: first, a simplified objective function is considered to guarantee the design simplicity of the H-inf channel estimator. Second, an expectation maximization...
In this paper, a method for multi-channel pitch estimation is proposed. The method is a maximum likelihood estimator and is based on a parametric model where the signals in the various channels share the same fundamental frequency but can have different amplitudes, phases, and noise characteristics. This essentially means that the model allows for different conditions in the various channels, like...
Vector quantization schemes are proposed to extract secret keys from correlated wireless fading channels. By assuming that the channel between two terminals are reciprocal, its estimates can be used as the common randomness for generating secret keys at the two terminals. Most schemes in the literature assume that channels are independent over time and utilize scalar quantization on each element of...
This paper deals with the estimation of a gramian-based interaction measure from logged process data, and thereby removing the need of creating parametric models prior to the selection of the significant input-output interconnections. Moreover, the resulting confidence regions of the estimates can be used to perform a robust control structure selection.
This paper presents a novel optimization method for blind multi-channel identification. The formulation of the optimal blind channel identification problem consists of three components: a least squares fitting term, and two regularization terms representing objective functions of the cross relation and the deterministic subspace methods, respectively. The proposed method is robust to noise since it...
In this paper, the Compressed Sensing (CS) based channel estimation scheme for the sparse multipath channel in OFDM system is considered. The CS based multipath delay channel model is investigated by using only a small amount of pilots to get the measurement matrix and the orthogonal matching pursuit (OMP) is adopted to reconstruct the channel impulse response. In order to overcome the drawback of...
This paper develops a detection scheme based on implicit pilot-symbol-assisted architecture for non-coherent amplify-and-forward (AF) relay networks. The networks use M-ary frequency-shift-keying (FSK) modulation and multiple relays to assist communication from a source to a destination. Built on the fact that every transmitted symbol from the source to the destination can be considered as a pilot...
Cognitive radio transmissions in the presence of channel uncertainty are considered. In practical scenarios, cognitive secondary users need to perform both channel sensing in order to identify whether the channel is being occupied by the primary users or not, and also channel estimation in order to learn the channel fading coefficients. Generally, errors occur in both channel sensing and estimation,...
This paper intends to analyze the performance of the widely used Enhanced Variable Rate Codec (EVRC) algorithm for suppressing background noise in speech Signals and propose a method for improving the current noise suppression capability of the algorithm. Firstly, the current EVRC algorithm is implemented on the TMS320C6713 based DSK in order to verify the algorithm and also to validate the real time...
A multi-user signal coordination scheme known as Vectoring will play a crucial role in next generation digital subscriber lines (DSL). Previous studies have demonstrated that vectoring increases the bitrate of DSL systems due to its ability to mitigate the interference. In this work we show how Vectoring improves the energy-efficiency of DSL over state-of-the-art spectrum balancing methods. In addition...
In this paper, power allocation between pilots and data symbols is investigated aiming at maximizing energy efficiency(EE) for downlink orthogonal frequency division multiple access (OFDMA) networks. We first derive an EE function when the channel estimation error is considered, which depends on the large-scale channel gains of multiple users, the allocated power to pilots and data symbols, and the...
The channel estimation is an important issue for safety and non safety applications of intelligent transportation systems (ITS). Communication would come to a standstill if there were no channel estimation. It is essential to know the channel characteristics before sending a signal so that we have a fair knowledge of how distorted our received signal could be. Hence proper estimation is a major requirement...
The proposed resource allocation scheme can boost the spectral efficiency of multi-user OFDMA wireless systems with heterogeneous delay requirements. The existing designs usually have two important assumptions that the users are delay insensitive and Channel State Information at the Transmitter (CSI) is perfect. In practice, users have heterogeneous delay requirements and CSI usually becomes outdated...
Vector Coding (VC) is a transmission scheme that can obtain path diversity gain while orthogonalizing multiple symbols. It has been shown that VC can provide good bit error rate (BER) performance compared to orthogonal frequency division multiplexing (OFDM). In addition VC has been proven to be the optimal partition of time domain channel. However, In VC, the eigenvectors of the channel matrix must...
We propose two novel algorithms based on compressive sensing theory to estimate and cancel narrow band interference (NBI) and estimate the channel in the presence of NBI for multiple-antenna orthogonal frequency division multiplexing systems. We also consider the case of multiple asynchronous NBI signals experiencing unknown independent frequency- selective fading channels. Simulation results demonstrate...
We propose a water-filling power allocation scheme for Turbo-BLAST system in the presence of channel state information imperfection. Subjected to the total transmit power constraint, the water-filling rule is used to allocate proper power for every sub-channel in order to improve channel capacity performance based on the imperfect channel state information. Simulation results show that the proposed...
The combination of orthogonal frequency division multiplexing (OFDM) and interleave division multiple access (IDMA), known as OFDM-IDMA, has been proposed as a promising multiple access scheme for wireless communications due to its low decoding complexity and potential of achieving high spectral efficiency. However, most of the work on OFDM-IDMA is in radio frequency (RF) communications scenarios...
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.