Massive multiple-input multiple-output (MaMi) systems have attracted much research attention during the last few years. This is because MaMi systems are able to achieve a remarkable improvement in data rate and thus meet the immensely ongoing traffic demands required by the future wireless networks. To date, the downlink training sequence (DTS) for the frequency division duplex (FDD) MaMi communications systems have been designed based on the idealistic assumption of white noise environments. However, it is essential and more practical to consider the colored noise environments when designing an efficient DTS for channel estimation. To this end, this paper proposes a new DTS design by exploring the joint use of spatial channel and noise covariance matrices, when the channel is not reciprocal but the coherence block length remains limited. We derive an analytical solution for the mean square error (MSE) based on the proposed training design with colored noise. In addition, this paper exploits the method of random matrix theory to provide an analytical solution for the downlink (DL) achievable sum rate of the regularized zero forcing beamforming (RZFBF) precoder. Numerical results demonstrate that using the proposed DTS design, the MSE of the channel estimate is significantly reduced compared with the conventional training designs with white noise. Furthermore, the results show that the proposed pilot design markedly improves the DL achievable SR over the conventional training designs, especially at relatively low signal-to-noise-ratio (SNR) levels. This enables FDD MaMi systems to operate under more practical scenarios of colored noise and limited coherence time environments.
The global food supply heavily depends on utilizing fertilizers to meet production goals. The adverse impacts of traditional fertilization practices on the environment have necessitated the exploration of new alternatives in the form of smart fertilizer technologies (SFTs). This review seeks to categorize SFTs, which are slow and controlled-release Fertilizers (SCRFs), nano fertilizers, and biological fertilizers, and describes their operational principles. It examines the environmental implications of conventional fertilizers and outlines the attributes of SFTs that effectively address these concerns. The findings demonstrate a pronounced environmental advantage of SFTs, including enhanced crop yields, minimized nutrient loss, improved nut
... Show MoreThis study successfully synthesized high-performance photodetectors based on Ag-WO3 core–shell heterostructures using a simple and economical two-step pulsed laser ablation in water method and has investigated the electrical characteristics of the Ag@WO3 nanocomposite heterojunction. The Hall effect tests indicate that the synthesized Ag@WO3 exhibits n-type conduction with a Hall mobility of 1.25 × 103 cm2V-1S-1. Dark current–voltage properties indicated that the created heterojunctions displayed rectification capabilities, with the highest rectification factor of around 1.71 seen at a 5 V bias. A photodetector’s responsivity reveals the existence of two response peaks, which are situated in the ultraviolet and visible region. The ph
... Show MoreThis study aims to reach the right of governorates that are not organized in a region to impose local legislation, including tax legislation, and the extent of the constitutionality of this legislation and its consistency with constitutional texts and legal rules. The imposition of local taxes finds its constitutional and legal basis in the Iraqi constitution for the year 2005 and the law of governorates not organized in a region.The imposition of local taxes corresponds to the principle of tax legality, which is reflected in the necessity of issuing tax laws from a competent authority, whether this authority is federal, regional or local. Rather, it is sufficient that it be competent
This research deals with the most important grammatical views of the science of the media of the Arab and Andalusian grammar is: Abu Ali al-Shloubini, who filled his name the pages of important grammatical books such as: (singer Al-Labib) Ibn Ibn Hisham, and the book (like and analogues), and (Hama Alhwama) for Suyuti, and other books The task, I have divided my research into the topics: I talked in the first section on his life and his biography and his works, and the second topic: it included his independent opinions and the third section contained the most prominent views selected The fourth and final topic, was his responses to grammarians, and concluded my research with the most prominent findings Research to them, which was the mos
... Show MoreThe Symbolic Interaction of the Kindergarten
The costume is a language that has carved itself into a path that is transformed over time in line with the development of human thought. The child theater is a form of communication between the individual and his society. The costume in the child's theater is seen as a sign of personality and identity. It is a model of communication that uses many of the world systems to which it belongs. Directed to the child by invoking the creative and creative energies of the designer in the formation of the children's theater. The second topic was the communicative function of secondary signs of uniforms and patterns of their transformations. The theoretical framework of the indicators included the on the research community. And his tools in the an
... Show MoreThis research paper studies the use of an environmentally and not expensive method to degrade Orange G dye (OG) from the aqueous solution, where the extract of ficus leaves has been used to fabricate the green bimetallic iron/copper nanoparticles (G-Fe/Cu-NPs). The fabricated G‑Fe/Cu-NPs were characterized utilizing scanning electron microscopy, BET, atomic force microscopy, energy dispersive spectroscopy, Fourier-transform infrared spectroscopy and zeta potential. The rounded and shaped as like spherical nanoparticles were found for G-Fe/Cu‑NPs with the size ranged 32-59 nm and the surface area was 4.452 m2/g. Then the resultant nanoparticles were utilized as a Fenton-like oxidation catalyst. The degradation efficiency of
... Show MoreThis research aims to study the effect of different pH values on the growth of CdTe nanoparticles during specific times. The reflux method has been used as a method for preparing CdTe quantum dots. A difference in absorbance and intensities of peaks at pH 10.5 and 11.5 was observed during the reaction period. The growth rate of the NPs (nucleation) was irregular at low pH values. Optical examinations showed that the best growth rate of NPs was at pH value 12.