The aim of the study was to evaluate the impact of defoliation intensity, defoliation frequency, and interactions with N supply on N uptake, N mobilization from and N allocation to roots, adult leaves, and growing leaves. Plants of Lolium perenne were grown under two contrasted N regimes. Defoliation intensity treatments consisted of a range of percentage leaf area removal (0, 25, 50, 75, or 10...

In the paper “Finite-SNR Diversity-Multiplexing Tradeoff for Network Coded Cooperative OFDMA Systems”, the authors adopt a recently proposed subcarrier allocation algorithm aiming at providing optimal frequency diversity to an OFDMA-based network with network-coded cooperation (NCC), where P source nodes transmit independent information to a common destination with the help of M relay nodes, in...

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 ...

This paper studies multiuser orthogonal frequency division multiplexing (OFDM) system using adaptive subchannel and power allocation with partial channel information. Previous research on multiuser OFDM includes margin adaptive (MA) optimization and rate adaptive (RA) optimization. The capacity gain using adaptive resource allocation over fixed resource allocation such as time division multiple...

One perspective in communication systems is to increase the spectrum utilization using cognitive radios. A cognitive radio is a network of intelligent co-existing radios which senses the environment to find the available frequency slots, white spaces, or the spectrum holes as noted in Akyildiz et al. (2008); Haykin (2005). Then, it modifies its transmission characteristics to use that particula...

In this paper, we present and analyze a Tabu Search (TS) algorithm for Dynamic Spectrum Allocation (DSA) in cellular networks. We study a case where an operator is providing packet services to the endusers. The objective of the cellular operator is to maximize its reward while taking into account the trade-off between the spectrum cost and the revenues obtained from end-users. These revenues ar...

Consider the link bandwidth allocation for transport of correlated traac on a single link with nite buuer capacity under a maximum allowable delay constraint d max. In our measurement architecture, traac is decomposed into three frequency regions: low-frequency (LF) traac in 0 < j!j ! L , high-frequency (HF) traac in j!j ! H and mid-frequency (MF) traac in ! L < j!j < ! H. The zero-frequency co...

Single carrier frequency division multiple access (SCFDMA) is one well-known scheme, which has recently become a preferred choice for uplink channels. Due to the usage of single carrier, the performance of SC-FDMA systems degrades in deep frequency selective fading channels. In this paper, we propose a structure of equalizer based on frequency domain decision feedback which could be used for mu...

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Scarcity and the value of spectrum resource for wireless communications challenged the traditional static spectrum allocation policy. Recent measurements [1] show that in spite of the fact that available frequency spectrum have been almost occupied by the existing carriers, most of the time we can find spectrum bandwidths that are free of signal. Thus, the efficient usage of limited spectrum ha...