Search results for "Plexin"
showing 10 items of 191 documents
Channel Estimation and Interference Cancellation for MIMO-OFDM Systems
2007
This paper proposes a new channel estimation method and a new interference cancellation scheme for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems in the presence of intersymbol interference (IS1). The proposed channel estimation method uses special training sequences (TSs) to have a desirable crest-factor of the transmitted training signal, and to prevent the influence of ISI on the channel estimation performance. By using the recommended training sequences, the ill-conditioned problem of the least square (LS) filter integrated in the proposed channel estimator can be avoided. The proposed interference cancellation scheme uses the estimated cha…
Performance Analysis of STBC-OFDM Systems in Temporally or Spatially Correlated Fading Channels
2010
This paper analyzes the performance of space-time block coded orthogonal frequency division multiplexing (OFDM) systems. In our analysis, we abandon the usually made assumption of quasi-static channel conditions. Instead of this, we consider the more general and realistic case that the channel envelope changes during two consecutive transmission time slots. In addition, we take the spatial correlation between sub-channels into account. We first present a general formal expression for the bit error probability (BEP), from which we find analytical solutions for the BEP not only for temporally fading channels but also for spatially correlated channels. The knowledge of the obtained analytical …
Mice lacking Plexin-B3 display normal CNS morphology and behaviour
2009
Semaphorins and their receptors, plexins, have emerged as important regulators of a multitude of biological processes. Plexin-B3 has been shown to be selectively expressed in postnatal oligodendrocytes. In contrast to the well-characterized Plexin-A family and the Plexin-B family members Plexin-B1 and -B2, no data are available on the functional role of Plexin-B3 in the central nervous system in vivo. Here we have elucidated the functional significance of Plexin-B3 by generating and analyzing constitutive knock-out mice. Plexin-B3-deficient mice were found to be viable and fertile. A systematic histological analysis revealed no morphological defects in the brain or spinal cord of mutant ani…
Channel aggregation with guard-band in D-OFDM based CRNs: Modeling and performance evaluation
2016
Channel aggregation (CA) techniques can offer flexible channel allocation and improve overall system performance in multi-channel cognitive radio networks (CRNs). Although many CA techniques have been proposed and studied, the impact of guard-band on CA for channel access has not been addressed in-depth. In this paper, we study the guard-band allocation mechanisms in discontinuous-orthogonal frequency division multiplexing (D-OFDM) based CRNs, and investigate the impact of guard-band sharing on SU flows when CA is enabled. Continuous time Markov chain (CTMC) based models have been developed in order to investigate the stochastic behavior of PU and SU flows. Based on our mathematical analysi…
Solution Processed Micro- and Nano-Bioarrays for Multiplexed Biosensing
2012
This Feature article reports on solution dispensing methodologies which enable the realization of multiplexed arrays at the micro- and nanoscale for relevant biosensing applications such as drug screening or cellular chips.
Spatial information transmission using orthogonal mutual coherence coding.
2005
We use the coherence of a light beam to encode spatial information. We apply this principle to obtain spatial superresolution in a limited aperture system. The method is based on shaping the mutual intensity function of the illumination beam in a set of orthogonal distributions, each one carrying the information for a different frequency bandpass or spatial region of the input object. The coherence coding is analogous to time multiplexing but with multiplexing time slots that are given by the coherence time of the illumination beam. Most images are static during times much longer than this coherence time, and thus the increase of resolution in our system is obtained without any noticeable c…
A simple method to fabricate high-performance nanostructured WO3 photocatalysts with adjusted morphology in the presence of complexing agents
2017
[EN] The rich and complex chemistry of tungsten was employed to synthesize innovative WO3 nanoplatelets/nanosheets by simple anodization in acidic electrolytes containing different concentrations of complexing agents or ligands, namely F- and H2O2. The morphological and photoelectrochemical properties of these nanostructures were characterized. The best of these nanostructures generated stable photocurrent densities of ca. 1.8 mA cm(-2) at relatively low bias potentials (for WO3) of 0.7 V-Ag/AgCl under simulated solar irradiation, which can be attributed to a very high active surface area. This work demonstrates that the morphology and dimensions of these nanostructures, as well as their ph…
An Improved Detection Technique for Cyclic-Prefixed OFDM
2010
A novel Orthogonal Frequency Division Multiplexing detection technique compatible to standard (e.g. Wireless LAN) transmitters is proposed. It features enhanced error-rate performance with flexible computational complexity and robustness to imperfect channel estimation. It is based on exploitation of the redundancy available in the cyclic prefix after cancellation of interference from the preceding block. In order to show the effectiveness of our proposal, an analysis of computational complexity and a number of comparisons to the standard per-subcarrier receiver and a previously existing method in terms of error rates are reported.
Resource allocation for clustered network MIMO OFDMA systems
2012
In this article, we address the resource allocation problem for the downlink of a large network multiple input multiple output orthogonal frequency division multiplexing system with 3-sector base stations. The system is statically divided into a number of disjoint clusters of sectors. A two-step resource allocation scheme is proposed involving the inter-cluster and the intra-cluster levels. As a first step or inter-cluster level, two cooperative frequency reuse approaches are designed to mitigate the inter-cluster interference. A user partition method is proposed to divide the users of each cluster into cluster-edge and cluster-center users. To balance the cell-edge and the cell-average per…
Energy-Efficient and Secure Resource Allocation for Multiple-Antenna NOMA with Wireless Power Transfer
2018
Non-orthogonal multiple access (NOMA) is considered as one of the promising techniques for providing high data rates in the fifth generation mobile communication. By applying successive interference cancellation schemes and superposition coding at the NOMA receiver, multiple users can be multiplexed on the same subchannel. In this paper, we investigate resource allocation algorithm design for an OFDM-based NOMA system empowered by wireless power transfer. In the considered system, users who need to transmit data can only be powered by the wireless power transfer. With the consideration of an existing eavesdropper, the objective is to obtain secure and energy efficient transmission among mul…