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.
This research, involved a series of some new compounds containing different hetero cyclic new pentagonal and hexagonal rings, through the reaction of 2-mercapto-3-phenyl-4(3H)quinazolinone (1) with chloroacetylchloride in the presence of potassium hydroxide, and dry dimethylformamide (DMF) as a solvent to obtain the intermediate compound (2). This compound is reacted with different reagents to give four routes, the first route include direct reaction with substituted-2-aminobenzothiazole under certain conditions to give new compounds (3-9). The second route involved condensation compound (2) with 5-substituted-2-amino-1,3,4-oxadiazole in the presence of potassium carbonate anhydrous to give new compounds (10-13).while the third route inv
... Show MoreBackground: Venous thromboembolic disease (VTED) is a well known complication that occur following total knee arthroplasty (T.K.A). One of the (VTED) forms is asymptomatic deep venous thrombosis with an incidence has been estimated to be up to ³ 20% in patients undergone primary T.K.A , despite routine treatment with heparin postoperatively.
Objectives : is to assess the prevalence of post-operative asymptomatic D.V.T among patients receiving two different thromboprophylactic drugs after T.K.A.
Patients and methods: 68 patients who had T.K.A were randomly divided for the purpose of post-operative thromboprophylaxis into two groups , group [ A ] (control group) consisted
... Show MoreThe study aims to implement a serial security technology system to organize a comfortable work environment for users of computers in the General Directorate of Education in Baghdad Karkh3. The most important findings of the study are the application of a serial technology system. It is connected with scientific goals that show the scientific structure of computer learning and its applications. It considers global learning systems and take into account the ease and scientific flow of the class of elderly employees. In addition, employees of other categories, are the outputs of the sequential technological system. The aim is to create a purposeful technological system and keep pace with global developments, to gain experience, skills and
... Show MoreThis research was conducted to investigate the water quality of the lesser Zab
river, to evaluate the water suitability for agricultural usings and report the effect of
human activities on this water. Samples were collected along the river stream
starting from Dukan area till the convergence with Tigris River. All the tests were
conducted at the labs of Environmental sciences and Technology College /
University of Mosul and Erbil water project/Erbil city.
The results of using Piper diagram showed that the water is alkine, due to the effect of the origional rock's components of that area on the water quality. While the using of Stiff diagram elucidate that the water samples contain ions belong to the area of the lesser Z
The main goal of this paper is to introduce the higher derivatives multivalent harmonic function class, which is defined by the general linear operator. As a result, geometric properties such as coefficient estimation, convex combination, extreme point, distortion theorem and convolution property are obtained. Finally, we show that this class is invariant under the Bernandi-Libera-Livingston integral for harmonic functions.
In this work, we introduce Fibonacci– Halpern iterative scheme ( FH scheme) in partial ordered Banach space (POB space) for monotone total asymptotically non-expansive mapping (, MTAN mapping) that defined on weakly compact convex subset. We also discuss the results of weak and strong convergence for this scheme.
Throughout this work, compactness condition of m-th iterate of the mapping for some natural m is necessary to ensure strong convergence, while Opial's condition has been employed to show weak convergence. Stability of FH scheme is also studied. A numerical comparison is provided by an example to show that FH scheme is faster than Mann and Halpern iterative
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