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.
An experiment was carried out on the fields of the college of Agriculture - Abu Ghraib, of a silty clay loam soil that has moisture of 15-16%, to study the effect of plowing and pulverization systems on some plant indicators of onion. The experiment included plowing systems with three levels (plowing with a moldboard plow, plowing by chisel plow and zero tillage plowing) as a primary factor. The second factor was that pulverization for only one time and repeating the pulverization twice through the use of the rotary tiller. The plant indicators of onion that are studied: plant length, onion diameter, onion weight and onion neck diameter. The experiment has carried out according to SPLIT PLOT design according to RCBD design by three replicat
... Show MoreBackground: Adjustment of any premature occlusal contact of any zirconia restoration requires its polishing or glazing in order to restore the smoothness of the restoration. The objective of this in vitro study was to evaluate the effects of different polishing systems and glazing on the surface roughness of full-contour zirconia. Material and methods: Forty disks (diameter: 8 mm, thickness: 6.4 mm) were prepared from pre-sintered full-contoured zirconia block; they were colored and sintered in a high-temperature furnace at 1500ËšC for 8 hours. The specimens were then leveled and finished using grinding and polishing machine and adjusted using diamond disk. The specimens were then randomly divided into four groups (n=10), group I involves
... Show MoreThe great progress in information and communication technology has led to a huge increase in data available. Traditional systems can't keep up with this growth and can't handle this huge amount of data. Recommendation systems are one of the most important areas of research right now because they help people make decisions and find what they want among all this data. This study looked at the research trends published in Google Scholar within the period 2018-2022 related to recommending, reviewing, analysing, and comparing ebooks research papers. At first, the research papers were collected and classified based on the recommendation model used, the year of publication, and then they were compared in terms of techniques, datasets u
... Show MorePerhaps going to watch movies in cinemas today has become different from what it was before. The cinematic film, the clarity of the image and the luster of its colors pulled the rug out from under the most important change that occurred in the structure of the contemporary cinematography, which is the sound. The surround sound environment that immerses viewers in the realism of sound that reaches them from all directions, and for this the researcher found it necessary to shed light on this topic because of its importance, so the research problem was represented in the following question: (How are modern sound systems used in the structure of contemporary feature films?) The theoretical framework included two topics: the first: the dialec
... Show MoreThis study aims to investigate the academic leaders’ perceptions towards the degree of availability of the dimensions of organizational immunity systems at the University of Tabuk, as well as to reveal the statistically significant differences between the average responses of the study sample members about the degree of availability of these dimensions at their university due to the variables of (gender, leadership position, and college specialization). To achieve the objectives of the study, a descriptive survey method was used. The study population consisted of (200) male and female leaders who were academic leaders at the University of Tabuk. A questionnaire was used as a tool for collecting data, which its validity and reliability
... Show MoreThe search (floors and transparent role in the design studios satellite channels) and presented as a study-oriented, and the research aims to identify the role of flooring transparent spaces studios satellite channels and side performative and aesthetic, and formulas design to highlight the role floors transparent spaces studios satellite channels. And highlight the importance of research, particularly in its contribution to the clarification of the concept of the relationship between transparency and performing aesthetic treatments for floors by clarifying its role in the designs of the internal spaces of the studios, as well as his contribution to the founding of the theory of looking at the base of such concepts. To achieve the object
... Show MoreAdvertising design is one of the arts of communication of various levels and one of the aspects of the fields of design arts, and that the construction of the design environment in the advertising is one of the important entry points in making the recipient feel this environment and feel as if being one of its elements. It is an entrance worthy of study and research and is a problem worth raising according to the following question: - What is the effectiveness achieved in the virtual design environment for digital advertising? The two researchers dealt with the research in three frameworks, the methodological framework which identified (the problem of research, its importance, purpose, limits, and the definition of ter
... Show MoreThe research dealt with the design of the cost accounting system for the transport service and its Role in improving the efficiency of pricing decisions through the application of the cost system based on ABC activities. The main activities were defined and cost guides were to measure the cost of each service and to determine the cost of each service for the purpose of providing management with appropriate information and pricing decisions The problem of research in the lack of adoption by some public companies in the service sector on the cost accounting system to calculate the cost of service as well as the lack of identification of productive activities and service activities and therefore cannot make the appropriate decision t
... Show MoreThe research is to identify the legend of the seven eyes amulet of Babylonian origin and the representations it carried of the link between the Babylonian past and the Islamic present presented in the design works of the promoted products, preserving its impact in the souls as a way to avoid the act of envy, and from this was the research problem that I want to get answers to, which That is (How was the legend of the seven-eyes amulet represented in the design of industrial products?), making its goal to identify how that legend was represented within the design work of marketed industrial products, and in order to reach the answer, the research presented many concepts starting with the legend in its various forms in industrial products.
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