New approaches and algorithms for the analysis of vertical refractivity profile below 1 KM in a subtropical region

YesIn this paper, 17 years of high resolution surface and radiosonde meteorological data from 1997-2013 for the subtropical Gulf region are analysed. Relationships between the upper air refractivity, Nh, and vertical refractivity gradient, ΔN, in the low troposphere and the commonly available data of surface refractivity, Ns are investigated. A new approach is discussed to estimate Nh and ΔN from the analysis of the dry and wet components of Ns, which gives better results for certain cases. Results are compared with those obtained from existing linear and exponential models in the literature. The investigation focusses on three layer heights at 65 m, 100 m and 1 km above ground level. Correlation between the components of Ns with both Nh and ΔN are studied for each atmospheric layer. Where high correlations were found, empirical models are derived from best-fitting curves

Coupling Measurements of an Antenna System Suitable for Relay-Aided WiMAX Network

YesIn this paper two novel antennas, suitable for access and backhaul links, are designed, fabricated and tested for a Relay Station in a WiMAX wireless network. A single modi¯ed E-shaped patch antenna is described, presenting 10 dB gain over 12.4% bandwidth. This antenna element is used for the design of a 4 £ 4 planar array which provides experimental gain of 21.2 dB. The antenna system on the Relay Station operates at 3.4 GHz and includes one single antenna element for access link realization and an antenna array for the backhaul link realization. These antennas are installed in two con¯guration arrangements and tested in terms of their radiation performances and coupling e®ects. The simulated and measured results are quite satisfactory and in good agreement at which the maximum coupling between the access and backhaul antennas is found below ¡25 dB for all tested cases

New methodology for predicting vertical atmospheric profile and propagation parameters in sub-tropical Arabian Gulf region

YesA new simplified approach is proposed to evaluate the vertical refractivity profile within the lowest 1 km of atmosphere from the analysis of surface refractivity, Ns, in areas where upper air data are not available. Upper-air measurements from the nearest available radiosonde location with similar surface profile to these sites are utilized. The profiles of Ns and refractivity extrapolated to sea level, No, obtained from surface meteorological data using both fixed stations and radiosonde are investigated and compared. Vertical refractivity gradient, ΔN, is evaluated at three atmospheric layer heights within the first kilometer above the ground in addition to propagation parameters relevant to each atmospheric layer. At six sites, different approaches are compared for the analysis of three important parameters; namely effective earth radius factor, k, anomalous propagation probability parameter, β0, and point refractivity gradient at 65 m not exceeded for 1% of time, dN1. The k-factor parameter is investigated using a new weighted average approach of ΔN at 65 m, 100 m and 1 km layers above the ground. The results are compared with the latest ITU maps and tables for the same area

A Simplified Improvement on the Design of QO-STBC Based on Hadamard Matrices

yesIn this paper, a simplified approach for implementing QO-STBC is presented. It is based on the Hadamard matrix, in which the scheme exploits the Hadamard property to attain full diversity. Hadamard matrix has the characteristic that diagonalizes a quasi-cyclic matrix and decoding matrix that are diagonal matrix permit linear decoding. Using quasi-cyclic matrices in designing QO-STBC systems require that the codes should be rotated to reasonably separate one code from another such that error floor in the design can be minimized. It will be shown that, orthogonalizing the secondary codes and then imposing the Hadamard criteria that the scheme can be well diagonalized. The results of this simplified approach demonstrate full diversity and better performance than the interference-free QO-STBC. Results show about 4 dB gain with respect to the traditional QO-STBC scheme and performs alike with the earlier Hadamard based QO-STBC designed with rotation. These results achieve the consequent mathematical proposition of the Hadamard matrix and its property also shown in this study

Towards a Seamless Future Generation Network for High Speed Wireless Communications

YesThe MIMO technology towards achieving future generation broadband networks design criteria is presented. Typical next generation scenarios are investigated. The MIMO technology is integrated with the OFDM technology for effective space, time and frequency diversity exploitations for high speed outdoor environment. Two different OFDM design kernels (fast Fourier transform (FFT) and wavelet packet transform (WPT)) are used at the baseband for OFDM system travelling at terrestrial high speed for 800MHz and 2.6GHz operating frequencies. Results show that the wavelet kernel for designing OFDM systems can withstand doubly selective channel fading for mobiles speeds up to 280Km/hr at the expense of the traditional OFDM design kernel, the fast Fourier transform

Novel Fractional Wavelet Transform with Closed-Form Expression

yesA new wavelet transform (WT) is introduced based on the fractional properties of the traditional Fourier transform. The new wavelet follows from the fractional Fourier order which uniquely identifies the representation of an input function in a fractional domain. It exploits the combined advantages of WT and fractional Fourier transform (FrFT). The transform permits the identification of a transformed function based on the fractional rotation in time-frequency plane. The fractional rotation is then used to identify individual fractional daughter wavelets. This study is, for convenience, limited to one-dimension. Approach for discussing two or more dimensions is shown

On the application of raised-cosine wavelets for multicarrier systems design

YesNew orthogonal wavelet transforms can be designed by changing the wavelet basis functions or by constructing new low-pass filters (LPF). One family of wavelet may appeal, in use, to a particular application than another. In this study, the wavelet transform based on raisedcosine spectrum is used as an independent orthogonal wavelet to study multicarrier modulation behaviour over multipath channel environment. Then, the raised-cosine wavelet is compared with other well-known orthogonal wavelets that are used, also, to build multicarrier modulation systems. Traditional orthogonal wavelets do not have side-lobes, while the raised-cosine wavelets have lots of side-lobes; these characteristics influence the wavelet behaviour. It will be shown that the raised-cosine wavelet transform, as an orthogonal wavelet, does not support the design of multicarrier application well like the existing well-known orthogonal wavelets

Full-Diversity QO-STBC Technique for Large-Antenna MIMO Systems

YesThe need to achieve high data rates in modern telecommunication systems, such as 5G standard, motivates the study and development of large antenna and multiple-input multiple-output (MIMO) systems. This study introduces a large antenna-order design of MIMO quasi-orthogonal space-time block code (QO-STBC) system that achieves better signal-to-noise ratio (SNR) and bit-error ratio (BER) performances than the conventional QO-STBCs with the potential for massive MIMO (mMIMO) configurations. Although some earlier MIMO standards were built on orthogonal space-time block codes (O-STBCs), which are limited to two transmit antennas and data rates, the need for higher data rates motivates the exploration of higher antenna configurations using different QO-STBC schemes. The standard QO-STBC offers a higher number of antennas than the O-STBC with the full spatial rate. Unfortunately, also, the standard QO-STBCs are not able to achieve full diversity due to self-interference within their detection matrices; this diminishes the BER performance of the QO-STBC scheme. The detection also involves nonlinear processing, which further complicates the system. To solve these problems, we propose a linear processing design technique (which eliminates the system complexity) for constructing interference-free QO-STBCs and that also achieves full diversity using Hadamard modal matrices with the potential for mMIMO design. Since the modal matrices that orthogonalize QO-STBC are not sparse, our proposal also supports O-STBCs with a well-behaved peak-to-average power ratio (PAPR) and better BER. The results of the proposed QO-STBC outperform other full diversity techniques including Givens-rotation and the eigenvalue decomposition (EVD) techniques by 15 dB for both MIMO and multiple-input single-output (MISO) antenna configurations at 10−3 BER. The proposed interference-free QO-STBC is also implemented for 16×NR and 32×NR MIMO systems, where NR≤2. We demonstrate 8 x 16 and 32 transmit antenna-enabled MIMO systems with the potential for mMIMO design applications with attractive BER and PAPR performance characteristics

Horn Antennas Loaded with Metamaterial for UWB Applications

YesIn this paper, a conical horn antenna has been designed for Ultra-Wideband ap-plications by loading its section with a metamaterial. The work aims first to compare results obtained by the wavelet-moment method to a simulation performed using HFSS. Secondly the conical horn is loaded with a very thin layer of metamaterial to enhance the radiation pattern and the bandwidth performance of the conical horn antenna and reduce the size of the antenna. The operating bandwidth of the proposed antenna is in the range of 10{13 GHz. The results obtained from HFSS and moment method are in good agreement.Electronics and Telecommunication

Performance Evaluation of Spatial Modulation and QOSTBC for MIMO Systems

YesMultiple-input multiple-output (MIMO) systems require simplified architectures that can maximize design parameters without sacrificing system performance. Such architectures may be used in a transmitter or a receiver. The most recent example with possible low cost architecture in the transmitter is spatial modulation (SM). In this study, we evaluate the SM and quasi-orthogonal space time block codes (QOSTBC) schemes for MIMO systems over a Rayleigh fading channel. QOSTBC enables STBC to be used in a four antenna design, for example. Standard QO-STBC techniques are limited in performance due to self-interference terms; here a QOSTBC scheme that eliminates these terms in its decoding matrix is explored. In addition, while most QOSTBC studies mainly explore performance improvements with different code structures, here we have implemented receiver diversity using maximal ratio combining (MRC). Results show that QOSTBC delivers better performance, at spectral efficiency comparable with SM