Linear Precoding and Equalization for Network MIMO with Partial Cooperation

A cellular multiple-input multiple-output (MIMO) downlink system is studied in which each base station (BS) transmits to some of the users, so that each user receives its intended signal from a subset of the BSs. This scenario is referred to as network MIMO with partial cooperation, since only a subset of the BSs are able to coordinate their transmission towards any user. The focus of this paper is on the optimization of linear beamforming strategies at the BSs and at the users for network MIMO with partial cooperation. Individual power constraints at the BSs are enforced, along with constraints on the number of streams per user. It is first shown that the system is equivalent to a MIMO interference channel with generalized linear constraints (MIMO-IFC-GC). The problems of maximizing the sum-rate(SR) and minimizing the weighted sum mean square error (WSMSE) of the data estimates are non-convex, and suboptimal solutions with reasonable complexity need to be devised. Based on this, suboptimal techniques that aim at maximizing the sum-rate for the MIMO-IFC-GC are reviewed from recent literature and extended to the MIMO-IFC-GC where necessary. Novel designs that aim at minimizing the WSMSE are then proposed. Extensive numerical simulations are provided to compare the performance of the considered schemes for realistic cellular systems.Comment: 13 pages, 5 figures, published in IEEE Transactions on Vehicular Technology, June 201

Carbon Nanotube-Based UV-Curable Nanocomposite Coatings

This chapter covers the preparation and properties of ultraviolet (UV)-curable nanocomposite containing carbon nanotubes as fillers. UV-curing technology is of particular interest due to its unique properties such as rapid curing process and solvent-free formulation. Alongside with the advantages of utilizing this curing method, carbon nanotubes undergo benefits including high aspect ratio, high transparency, and good mechanical properties. Carbon nanotubes (CNTs) are hollow cylindrical shaped configuration; consist of one, two, or more walls with an interlayer of non-covalent van der Waals force acting among the carbon atoms of various walls. Besides influencing the UV curing process, the CNTs loaded UV-curable nanocomposites sustain modified surface, thermal, mechanical, physical, and conductive properties which are discussed in this chapter. The health and safety concerns of using these classes of nanocomposite are further discussed

Robust Joint Precoder and Equalizer Design in MIMO Communication Systems

We address joint design of robust precoder and equalizer in a MIMO communication system using the minimization of weighted sum of mean square errors. In addition to imperfect knowledge of channel state information, we also account for inaccurate awareness of interference plus noise covariance matrix and power shaping matrix. We follow the worst-case model for imperfect knowledge of these matrices. First, we derive the worst-case values of these matrices. Then, we transform the joint precoder and equalizer optimization problem into a convex scalar optimization problem. Further, the solution to this problem will be simplified to a depressed quartic equation, the closed-form expressions for roots of which are known. Finally, we propose an iterative algorithm to obtain the worst-case robust transceivers.Comment: 2 figures, 5 pages, conferenc

Jashn-e Bahmangaan

This song celebrates the Jashn-e Bahmangaan festival in Iran. On the day Bahman and the month Bahman, a celebration is held to honor the first Amshaaspand (Holy Immortal), representing AhuraMazdaa’s attribute of Good Thoughts (اندیشه نیک). Bahman is also known as Vohooman (وهومن), or Vohoomana (وهومنه). It means Good (خوب و نیک), Thinking (اندیشیدن), Remembering (به یاد آوردن), and understanding (دریافتن). According to the Zoroastrian/Iranian literature, Bahman represents the first creation of AhuraMazdaa. It was Bahman that taught humans the skills of thinking and problem solving. The wisdom and knowledge that people have (both acquired and innate) are gifts of the Creator so that they can continue to learn and improve their lives. That is the reason why Zoroaster emphasized freedom of choice (آزادیِ گزینش در زندگی) in his teachings. Before making important decisions, individuals are encouraged to consult with other wise and knowledgeable people. They are also encouraged to avoid unnecessary conflicts and wars by negotiating with the opponents and seeking peace.https://digitalcommons.cwu.edu/kaviani/1005/thumbnail.jp

Sum rate maximization of MIMO broadcast channels with coordination of base stations

Abstract-We consider cooperative downlink transmission in multiuser, multi-cell and multiple-antenna cellular networks. Recently, it has been shown that multi-base coordinated transmission has significant spectral efficiency gains over that without coordination. The capacity limits can be achieved using a non-linear precoding technique known as dirty paper coding, which is still infeasible to implement in practice. This motivates investigation of a simpler linear precoding technique based on generalized zero-forcing known as block diagonalization (BD). In this paper, an enhanced form of BD is proposed for multiple-input multiple-output (MIMO) multi-base coordinated network. It involves optimizing the precoding over the entire null space of other users' transmissions. The performance limits of the multiple-antenna downlink with multi-base coordination are studied using duality of MIMO broadcast channels (BC) and MIMO multiple-access channels (MAC) under per-antenna power constraint, which has been established recently

Different Methylation Patterns of RUNX2, OSX, DLX5 and BSP in Osteoblastic Differentiation of Mesenchymal Stem Cells

Objective: Runt-related transcription factor 2 (RUNX2) and osterix (OSX) as two specific osteoblast transcription factors and distal-less homeobox 5 (DLX5) as a non-specific one are of paramount importance in regulating osteoblast related genes including osteocalcin, bone sialoprotein (BSP), osteopontin and collagen type Iα1. The present study sets out to investigate whether epigenetic regulation of these genes is important in osteoblastic differentiation of mesenchymal stem cells (MSCs). Materials and Methods: In this experimental study, MSCs were differentiated to osteoblasts under the influence of the osteogenic differentiation medium. DNA and RNA were extracted at days 0, 7, 14 and 21 from MSCs differentiating to osteoblasts. Promoter regions of RUNX2, OSX, DLX5 and BSP were analyzed by methylation-specific PCR (MSP). Gene expression was analyzed during osteoblastic differentiation by quantitative real-time polymerase chain reaction (PCR). Results: MSP analysis revealed that promoter methylation status did not change in RUNX2, DLX5 and BSP during MSC osteoblastic differentiation. In contrast, OSX promoter showed a dynamic change in methylation pattern. Moreover, RUNX2, OSX, DLX5 and BSP promoter regions showed three different methylation patterns during MSC differentiation. Gene expression analyses confirmed these results. Conclusion: The results show that in differentiation of MSCs to osteoblasts, epigenetic regulation of OSX may play a leading role

Jashn-e Khordaadgaan

Jashn-e Khordaadgaan or Khordadgan (جشن خردادگان) is about celebrating and honoring water. Khordaad or Khordad is the third month in the Iranian calendar and the name of the fifth Holy Immortal. Holy Immortals are more powerful than the Guardians. They all have different strengths and qualities. Khordaad Amshaaspand (خرداد امشاسپند) has three helpers (Farvardeen فروردین = The Energy of Progress and movement of lifeنیروی پیشرفت و نیرویی که هستی را به جنبش آورد ; Teshtar تشتر = Rain Starستاره باران ; Baad باد = Wind and its various manifestations that include (1) the loud inspiring voices that give the brave the courage to move forward and continue the fight, (2) the loud shouts given out when in need, (3) the loud voices that indicate the arrival of the much needed help, (4) breathing, (5) the wind that brings the rain clouds over to deposit their water on land, etc.) that ensure the water gets to all corners of the earth to quench the thirst of all living creatures. This festival shows the importance of water in our world and the perennial nature of the struggle between drought and rain. As the competition for this scarce resource heats up, we all need to do our part to honor, preserve, and protect this valuable resource.https://digitalcommons.cwu.edu/kaviani/1004/thumbnail.jp

DNA methylation is involved in the microRNA-886-3p gene expression and plays a potential role in hematopoietic stem and progenitor cell mobilization through affecting SDF-1

103-110The role of the sympathetic nervous system (SNS) in hematopoietic stem and progenitor cell (HSPC) mobilization has been largely investigated. However, there is a critical need for the identification of the underlying contributing factors to improve HSPC yield for transplantation. It has been demonstrated that miR-886-3p targets stromal-derived factor-1 (SDF-1), the central mediator of mobilization, and therefore may play a part in this process. Besides, miR-886-3p expression can be epigenetically regulated through DNA methylation modifications inits gene promoter. Here, to assess the contribution of miR-886-3p and other epigenetic factors in HSPC mobilization, human bone marrow-derived mesenchymal stem cells (MSCs) were treated with the β-adrenergic agonist of isoprenaline. The expression of miR-886-3p and SDF-1and the gene promoter methylation status of this miRNA were then respectively evaluated through the appropriate PCR techniques. As expected, despite a transient initial increase in SDF-1mRNA level, its expression reduced, and miR-886-3plevel remarkably increased 48 h following treatment. The gene promoter methylation pattern of miR-886-3p also changed from a full methylated state to a partially methylated one. Together, our findings suggest that miR-886-3p can be epigenetically regulated and through suppressing the expression of SDF-1 play an active role in the SNS-mediated HSPC mobilization

Optimal Multiuser Zero Forcing with Per-Antenna Power Constraints for Network MIMO Coordination

<p/> <p>We consider a multicell multiple-input multiple-output (MIMO) coordinated downlink transmission, also known as network MIMO, under per-antenna power constraints. We investigate a simple multiuser zero-forcing (ZF) linear precoding technique known as block diagonalization (BD) for network MIMO. The optimal form of BD with per-antenna power constraints is proposed. It involves a novel approach of optimizing the precoding matrices over the entire null space of other users' transmissions. An iterative gradient descent method is derived by solving the dual of the throughput maximization problem, which finds the optimal precoding matrices globally and efficiently. The comprehensive simulations illustrate several network MIMO coordination advantages when the optimal BD scheme is used. Its achievable throughput is compared with the capacity region obtained through the recently established duality concept under per-antenna power constraints.</p