197 research outputs found
On the Reduced Complexity Interleaving Method for OFDM PAPR Reduction
Many methods for OFDM Peak to Average Power Ratio reduction have been proposed during approximately last ten years. There are nowadays many research efforts on PAPR reduction methods with reduced computational complexity. The method presented in this paper is based on adaptive symbol selection principle, with several replicas of signal created using set of interleavers incorporated inside an IFFT block at OFDM transmitter. This paper also discusses some practical aspects of this method - influence of zero padding and pilot positions
Chip Interleaving and its Optimization for PAPR Reduction in MC-CDMA
This paper analyzes the usability of peak to average power ratio (PAPR) reduction in multicarrier code division multiple access (MC-CDMA) by the chip interleaving optimization. This means chip position formatting to PAPR minimization. One chip interleaving pattern is used for all users in system (all spreading sequences). Dependency on number of subcarriers and spreading sequence length is simulated. The impact on amplitude histogram is presented and relation to random interleaving pattern is shown
The Interplay of Structure and Dynamics in the Raman Spectrum of Liquid Water over the Full Frequency and Temperature Range
While many vibrational Raman spectroscopy studies of liquid water have
investigated the temperature dependence of the high-frequency O-H stretching
region, few have analyzed the changes in the Raman spectrum as a function of
temperature over the entire spectral range. Here, we obtain the Raman spectra
of water from its melting to boiling point, both experimentally and from
simulations using an ab initio-trained machine learning potential. We use these
to assign the Raman bands and show that the entire spectrum can be well
described as a combination of two temperature-independent spectra. We then
assess which spectral regions exhibit strong dependence on the local
tetrahedral order in the liquid. Further, this work demonstrates that changes
in this structural parameter can be used to elucidate the temperature
dependence of the Raman spectrum of liquid water and provides a guide to the
Raman features that signal water ordering in more complex aqueous systems
Communication Subsystems for Emerging Wireless Technologies
The paper describes a multi-disciplinary design of modern communication systems. The design starts with the analysis of a system in order to define requirements on its individual components. The design exploits proper models of communication channels to adapt the systems to expected transmission conditions. Input filtering of signals both in the frequency domain and in the spatial domain is ensured by a properly designed antenna. Further signal processing (amplification and further filtering) is done by electronics circuits. Finally, signal processing techniques are applied to yield information about current properties of frequency spectrum and to distribute the transmission over free subcarrier channels
Dynamic inundation simulation of storm water interaction between sewer system and overland flows
Copyright © 2002 Taylor & FrancisThis is the Author's Accepted Manuscript of an article published in the Journal of the Chinese Institute of Engineers (2002), available online at: http://www.tandfonline.com/10.1080/02533839.2002.9670691An improved urban inundation model, coupling a 2D non‐inertia overland flow model with a storm water management model, is adopted to simulate inundation in urban areas. The model computes, not only the overland runoff and the water overflow through manholes where surface runoff exceeds the capacity of storm sewers, but also the bidirectional flow interactions between sewers and overland runoff. The model was verified by a typhoon event in Nov. 2000, which resulted in serious inundation in the Mucha area of Taipei City. The result shows that the present model indeed improves simulation accuracy over the earlier model, and can be used to provide a more reliable flood mitigation design
Water Quality Monitoring: A comparative case study of municipal and Curtin Sarawak’s lake samples
In this study, particle size distribution and zeta potential of the suspended particles in municipal water and lake surface water of Curtin Sarawak's lake were compared and the samples were analysed using dynamic light scattering method. High concentration of suspended particles affects the water quality as well as suppresses the aquatic photosynthetic systems. A new approach has been carried out in the current work to determine the particle size distribution and zeta potential of the suspended particles present in the water samples. The results for the lake samples showed that the particle size ranges from 180nm to 1345nm and the zeta potential values ranges from -8.58 mV to -26.1 mV. High zeta potential value was observed in the surface water samples of Curtin Sarawak's lake compared to the municipal water. The zeta potential values represent that the suspended particles are stable and chances of agglomeration is lower in lake water samples. Moreover, the effects of physico-chemical parameters on zeta potential of the water samples were also discussed
Two Dimensional Signal Spreading in UMTS LTE: Exploiting Time-Frequency Diversity to Increase Throughput
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