Due to the high-power consumption and complexity of fully digital baseband precoding, its implementation in massive millimeter-wave multiple-input multiple-output (MIMO) systems is not cost-efficient and practical; for this reason, Hybrid precoding has attracted a lot of attention in recent years.  Most Hybrid precoding techniques concentrate on the fully-connected structure, although they require lots of phase shifters, which is high energy-consuming. On the contrary, the partially-connected structure has low power consumption, nevertheless, suffers from a severe decrease in spectral efficiency (SE). To enhance SE, this paper proposed a dynamic Hybrid precoding structure where a switch network is able to provide dynamic connections from phase shifters to radio frequency (RF) chains. To determine the digital precoder and the states of switch, a novel alternating minimization algorithm is proposed, which leverages closed-form solutions at each iteration to efficiently converge to an optimal solution. Furthermore, the phase shifter matrix is optimized through an iterative solution. The simulation results show that in terms of SE, the proposed algorithm with a dynamic structure achieves higher performance than the partial structure. Also, since the proposed structure reduces the number of phase shifters, it can guarantee better energy efficiency (EE) than the fully connected structure.

Millimeter wave (mmWave) communication, which utilizes massive multiple input multiple output (MIMO) techniques, is one of the key enabling technologies for high capacity 5G cellular networks.However, the hardware complexity and the high power consumption in massive-MIMO array hinder its integration.Hybrid precoding technique, which combines large-dimensional analog preprocessing with low-dimensional digital processing can be used to reduce both hardware costs and power consumption in massive MIMO systems, as a potential method. In this paper, we introduce a Hybrid precoding structure design in both narrowband and wideband massive MIMO inspired by the effective alternating minimization (AltMin) algorithm with the Least Squares Amendment (LSA). To be specific, in the proposed design, the analog Radio Frequency (RF) precoder structure employs the Discrete Fourier Transform (DFT) processing which in turn affects the performance of the system. In addition, the proposed design relies on Space-Time Block Coding (STBC) to attain diversity and further enhances the system reliability. We evaluate bit error rate (BER) performance of proposed massive MIMO system using various Hybrid precoding techniques. Numerical simulations (Monte Carlo) are performed to check the precision of proposed BER analytical expression. Our simulation results demonstrate significant performance gains of the proposed STBC-based Hybrid precoding with DFT processing over existing Hybrid precoding algorithms.

Orthogonal frequency division multiplexing (OFDM) is an attractive approach for multi-channel transmission. Due to some advantages such as high spectral efficiency, simplicity in channel equalization, and robustness to the fading channel, the OFDM technique has been generally used in many wireless communication devices. Besides these advantages, the OFDM systems usually experience a high peak-to-average power ratio (PAPR). As a result of the high PAPR, the OFDM signal is clipped during the passing via a non-linear power amplifier. The precoding techniques decrease the autocorrelation of the input data symbols to mitigate the high PAPR. In this paper, we compare WHMT, VLMT, DCMT, DHMT, DFMT, ZCMT, and CVMT precoding approaches in terms of autocorrelation and PAPR reduction performance. We demonstrate that the serial combinations of both ZCMT and CVMT precoding matrices with the IFFT matrix cancel the impact of each other when their dimensions are the same. In this case, a sparse matrix is produced and hence the PAPR of the OFDM signal is remarkably reduced. This issue is proved by the mathematical calculations and verified by the simulation results. It is also presented that DFMT, ZCMT, and CVMT precoding schemes have almost the same PAPR reduction performance and they are the best among their counterparts.

Rosa Hybrida is a perennial plant that after cut off head of the stem, lateral buds become free from apical dominance and begin to growth. In each new period of growth, new and young leaves can be formed. The four leaf samples were numbered from apex to base, showing young to mature leaf stages and some biochemical pigment markers changes were studied. The results suggest that during maturation, in addition to morphological differences, some physiological and biochemical markers are change. Data showed age dependent increase in the amount of pigments such as chlorophylls and carotenoids to reach the stage of leaf maturity to improve the leaf photosynthetic system efficiency. Gradually reducing in content of phenolic compounds, anthocyanins and flavonoids suggest reduction on oxidative damage.

In this paper, the performance of a system in terms of the energy efficiency (EE) is studied. To check the EE performance, an appropriate power is allocated to each user. The system in question in this paper is a multiple-input multiple-output (MIMO) system with non-orthogonal multiple access (NOMA) method. precoding in this system is considered to be the zero forcing (ZF). It is also assumed that the channel state information (CSI) mode is perfect. First, all the parameters that affect the channel, such as path loss and beam forming are investigated, and then the channel matrix is obtained. To improve system performance, better conditions are provided for users with poor channel conditions. These conditions are created by allocating more appropriate power to these users, or in other words, the total transmission power is divided according to the distance of users from the base station (BS) and the channel conditions of each user. The problem of maximizing the EE is formulated with two constraints of the minimum user rate and the maximum transmission power. This is a non-convex problem that becomes a convex problem using optimization properties, and because the problem is constrained it becomes an unconstrained problem using the Lagrange dual function. Numerical and simulation results are presented to prove the mathematical relationships which show that the performance of the proposed scheme is improved compared to the existing methods. The simulation results are related to two different algorithms with a same objective function. Furthermore, to comparison with performance of other methods, output of these two algorithms are also compared with each other.

Presently, due to emergence of new generation of wireless telecommunication networks, some appropriate capacity and coverage have been provided for end-users by new Hybrid terrestrial-satellite networks, consisting of two or more satellites in different orbits and terrestrial equipment. Today, due to the lack of spectral resources, a method, such as cognitive radio is used to allow for coexistence of spectrum between different nodes. Therefore, in this paper, spectral coexistence method between two satellites was applied over a common region based on cognition link to manage energy efficiency. Also, for mitigating interferences between satellites in downlink channel, the Stackelberg game was exploited. According to simulation results, the proposed algorithm for a primary satellite system with a main node had more energy efficiency compared to the other algorithms, such as sequential convex approximation (SCA)-based precoding, multi-beam interference mitigation (MBIM), and zero-forcing (ZF)-based precoding.

Rose is considered as one of the most popular and important ornamental plants in the world. During the last decade, tissue culture, micropropagation as well as genetic engineering have prevailed in rose production industry. Gene transfer to embryogenic callus, derived from different types of explants is currently one of the most popular methods of improvement of rose cultivars, presented in particular as cut flower with such novel characteristics as blue color. An efficient tissue culture procedure covering high frequency embryogenic callus induction and plant regeneration is pre-requisite for every successful genetic engineering program. An efficient method for embryogenic callus induction from growing nodal stem segments on MS medium followed by a selection of appropriate young leaflets is hereby reported. MS medium complemented with 2 mg/L 2, 4-D, and 0.5 mg/L NAA as wekk as medium B5 complemented with 0.5 mg/L 2, 4-D and 2.5 mg/L NAA plus 0.5mg/L kinetin were used for callus induction. Cali were then subcultured in MS medium with higher levels of hormone (3 mg/L 2, 4-D and 0.5 mg/LNAA) to develop suitable size and shape embryos. This was followed by transferring the calli onto an MS medium complemented with 8 hormonal treatments. MS medium along with 1 mg/L of TDZ resulted in a highest number of embryos. High frequency of shoot development from mature somatic embryo and subsequent plant regeneration were obtained on a medium containing 3 mg/L of BAP. Shoots were rooted on MS medium supplemented with three various hormonal treatments, and there were no significant differences observed between treatments.

Calcium crystals are evident in many parts of anther. There is little literature about differentiation of crystal-containing cells and crystal formation during anther development. Petunia Hybrid grandiflora Flower buds collected at different developmental stages were fixed and studied. The results revealed that young anthers are tetrasporangiate and in each of the four corners, the primary parietal layer externally and primary sporogenous cells internally, arise from periclinal divisions of the archeosporial cells. In the young anther, septum and connective cells contain calcium crystals as druse. At stomium, there is an arrangement of a band of 8-14 cells just beneath the epidermis which densely stain and lack visible vacuoles. During the division of sporogenous cells and the formation of crescent shaped tissue, no crystals are seen in hypodermal cells. In this stage, druse crystals become larger in connective tissue. While meiosis is occurring, the hypodermal cells of stomium are elongated, yet crystals are not observable. During pollen development, hypodermal cells degenerate and sand crystals appear. It seems that these crystals result from druse crystal.