Bandwidth-efficient pilot symbol aided technique for trellis-coded modulation in land mobile satellite fading channels

A bandwidth-efficient pilot-symbol-aided technique is proposed for use with trellis-coded modulation (TCM). Computer simulation has been used to assess the effects of the technique on the bit error rate (BER) performances of trellis-coded 16-ary quadrature amplitude modulation (TC-16QAM) in the flat Rician and shadowed Rician fading channels corrupted with additive white Gaussian noise. The results have shown that the proposed technique needs a very low bandwidth redundancy and can work effectively at low signal-to-noise ratios, so it is suitable for use with TCM.published_or_final_versionThe IEEE Conference on Wireless Communications and Networking (WCNC 1999), New Orleans, LA., 21-24 September 1999. In IEEE Wireless Communications and Networking Conference Proceedings, 1999, v. 1, p. 183-18

Combining PSA fading estimation techniques for TCM and diversity reception in Rician fading channels

In this paper, a novel pilot-symbol-aided (PSA) technique is proposed for fading estimation in the land mobile satellite fading channels. The proposed technique combines the fading estimates obtained from a bandwidth-efficient technique and a conventional technique according to the signal-to-noise ratios (SNRs) of the fading estimates. To enhance the transmission quality, trellis-coded modulation (TCM) and diversity reception are employed in the system, and the combined estimates are subsequently used to correct the channel fading effects, to weight the signals from different diversity branches, and to provide channel state information of the Viterbi decoder. Monte Carlo computer simulation has been used to study the bit-error-rate (BER) performance of the proposed technique on trellis-coded 16-ary quadrature amplitude modulation in the frequency non-selective Rician fading channels. Results have shown that the proposed PSA technique requires a very low bandwidth redundancy to provide satisfactory BER performance at low SNRs, and thus is suitable for use with TCM and diversity reception to achieve both bandwidth and power-efficient transmission.postprin

Data-aided fading estimation technique for shadowed mobile satellite fading channels

A novel data-aided fading estimation technique that employs both pilot and data symbols is proposed to significantly reduce the bandwidth redundancy of the pilot-symbol-aided (PSA) systems using receivers with low complexity and latency in the shadowed mobile satellite fading channels. The shadowed mobile satellite fading channels are modeled as the sum of a lognormally distributed direct component and a Rayleigh distributed multipath component, and the PSA system employs 16-ary quadrature-amplitude-modulation (16QAM) for transmission. Monte Carlo computer simulation has been used to assess the technique on the bit-error-rate (BER) performances of the system in the light shadowed, the average shadowed and the heavy shadowed Rician fading environments. The results have shown that the proposed technique requires a very low bandwidth redundancy to provide satisfactory BER performances, and can substantially lower the error floors of the PSA systems.postprin

Bandwidth-efficient pilot-symbol-aided technique for multipath-fading channels

Pilot-symbol-aided (PSA) transmission is one of the effective methods to combat multipath fading in digital mobile communications systems. In the PSA systems, redundant bandwidth and power are required to transmit the pilot symbols. In this paper, we propose a novel fading estimation technique that requires a very low bandwidth redundancy in the PSA systems. The proposed technique uses simple linear interpolation on the pilot symbols and the detected data symbols to obtain the estimates of the channel fading effects. Monte Carlo computer simulation has been carried out to study the effects of the technique on the bit error rate performance of 16-ary quadrature amplitude modulation in the flat and the frequency-selective Rayleigh-fading channels corrupted with cochannel interference and additive white Gaussian noise. Results have shown that the proposed technique can, at the expense of a little power efficiency, significantly improve the bandwidth efficiency of the PSA systems using receivers with low com plexity and latency.published_or_final_versio

Combining pilot-symbol-aided techniques for fading estimation and diversity reception in multipath fading channels

A novel pilot-symbol-aided (PSA) fading estimation technique that combines the estimates from a conventional PSA technique and a bandwidth-efficient PSA technique to achieve better performances is proposed for digital signals in multipath fading channels. The conventional technique has better performances at low signal-to-noise ratios (SNRs), while the bandwidth-efficient technique is superior at high SNRs. Monte Carlo computer simulation has been used to assess the effects of the proposed combining technique on the bit-error-rate (BER) performances of 16-ary quadrature-amplitude-modulation (16QAM), with and without two-branch diversity reception, in a flat Rayleigh fading channel. Results have shown that the combining technique has the advantages of both of the conventional technique and the bandwidth-efficient technique and is more preferred for use with diversity reception. © 2006 Springer Science + Business Media, Inc.postprin

S- and X-band SAR data fusion

This paper investigates the benefits deriving from introducing a wavelet-transform-based fusion framework for multi-frequency Synthetic Aperture Radar (SAR) data. A specific application is considered in the assessment of the fused classification map derived and this is the discrimination of different kinds of oil in sea. S-band and X-band datasets, concurrently acquired from the same airborne platform, have here been used. The findings suggest that fusing S-band and X-band SAR data does improve the oil type discrimination between crude oil and diesel oil used in the exercise, although a more quantitative analysis should be conducted in the future to measure the degree of improvement

Poly[dimethylammonium aquadi-μ-oxalato-europate(III) trihydrate]

In the crystal structure of the polymeric title compound, (C2H8N)[Eu(C2O4)2(H2O)]·3H2O, the independent oxalate that lies on a general position chelates to two Eu atoms, as do the other two oxalates that lie on different centres of inversion, the bridging mode of the oxalates giving rise to a three-dimensional anionic network. The water-coordinated Eu atom exists in a tricapped trigonal–prismatic geometry. The cations and solvent water mol­ecules occupy the cavities of the network and are involved in hydrogen bonding with each other and with the network.published_or_final_versio

Characterization of low-frequency noise in molecular beam epitaxy-grown GaN epilayers deposited on double buffer layers

Author name used in this publication: W. K. FongAuthor name used in this publication: S. W. NgAuthor name used in this publication: B. H. Leung2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Discovery of Mount Mazama cryptotephra in Lake Superior (North America): Implications and potential applications

Tephrochronology is a widely applied method recognized for its exceptional precision in geologic dating and stratigraphic correlation. Tephra from the ~7.6 kyr B.P. Mount Mazama caldera-forming (”climactic”) eruption have been widely identified and applied as stratigraphic isochrons sediments of northwestern North America, as well as in the Greenland ice core records. Recent findings of a microscopic tephra accumulation, or cryptotephra, from Mazama in Newfoundland indicated that this horizon should also be found in Lake Superior sediments. We present findings that confirm the presence of Mazama ash in two sediment cores from the Lake Superior basin, which indicates its likely presence in the rest of the Laurentian Great Lakes and in deposits throughout much of eastern North America and beyond. The ubiquity of this stratigraphic horizon should be applicable to a higher resolution evaluation of climatological, ecological, and archaeological events during the early- to mid-Holocene thermal maximum throughout much of North America.This research was supported by a Regents Professor grant by the University of Minnesota to Johnso

PCR amplification of alleles at locus D17S5: population genetic study in Hong Kong Chinese and detection of allelic loss in patients with hepatocellular carcinoma

Abstract no. 2184published_or_final_versio