Maximum Cell Capacity Research Articles

LTE Capacity Estimation with Changing Different Planning Parameters

Capacity improvement is the essential advantages in 4th generation mobile systems which called Long-Term Evolution (LTE). The maximum data transmission rate of LTE cell is 100 Mb/s in downlink direction and 50Mb/s in uplink, and this rate can be enhanced with deploying different techniques like MIMO, carrier aggregation, and many others. Because of that 4G-LTE mobile network is considered pure packet switching, there are many parameters which affect the maximum cell capacity. This study will evaluate the result of changing many parameters on the maximum mobile cell capacity. The aim is to extract the best values of the different parameters to maximize LTE mobile cell capacity.

A low-complexity algorithm for the joint antenna selection and user scheduling in multi-cell multi-user downlink massive MIMO systems

The massive MIMO (multiple-input multiple-output) technology plays a key role in the next-generation (5G) wireless communication systems, which are equipped with a large number of antennas at the base station (BS) of a network to improve cell capacity for network communication systems. However, activating a large number of BS antennas needs a large number of radio-frequency (RF) chains that introduce the high cost of the hardware and high power consumption. Our objective is to achieve the optimal combination subset of BS antennas and users to approach the maximum cell capacity, simultaneously. However, the optimal solution to this problem can be achieved by using an exhaustive search (ES) algorithm by considering all possible combinations of BS antennas and users, which leads to the exponential growth of the combinatorial complexity with the increasing of the number of BS antennas and active users. Thus, the ES algorithm cannot be used in massive MIMO systems because of its high computational complexity. Hence, considering the trade-off between network performance and computational complexity, we proposed a low-complexity joint antenna selection and user scheduling (JASUS) method based on Adaptive Markov Chain Monte Carlo (AMCMC) algorithm for multi-cell multi-user massive MIMO downlink systems. AMCMC algorithm is helpful for selecting combination subset of antennas and users to approach the maximum cell capacity with consideration of the multi-cell interference. Performance analysis and simulation results show that AMCMC algorithm performs extremely closely to ES-based JASUS algorithm. Compared with other algorithms in our experiments, the higher cell capacity and near-optimal system performance can be obtained by using the AMCMC algorithm. At the same time, the computational complexity is reduced significantly by combining with AMCMC.

8-Hydroxyquinoline-5-sulfonic acid on reduced graphene oxide layers as a metal-free electrode material for supercapacitor applications

Quinone organic materials are promising candidates to construct supercapacitor electrodes as they are entirely nontoxic, nonflammable, and safe for use. However, their wide adoption in supercapacitor applications is restricted by the inadequate electrical conductivity, which results in low mass and electron transfer, thereby leading to poor electrochemical performance. Herein, redox active 8-hydroxyquinoline-5-sulfonic acid (HQSA) compositing with reduced graphene oxide (rGO) through wet-chemistry method, as a high-performance electrode material is reported. Non-covalently interacted HQSA with rGO results in low internal resistance and high reversibility of the redox reaction. The as-prepared metal- and binder-free electrode in three-electrode cell configuration exhibits the specific capacity of 220C/g (61.1mAh/g), demonstrating a 208% increase in capacity than bare rGO (105.5C/g or 29.3mAh/g) at the same specific current of 0.5 A/g in 1M H2SO4 electrolyte solution. This electrode material shows an excellent cyclic stability with 99% capacity retention after 10,000 consecutive voltammetry cycles at 100mV/s. Furthermore, a symmetrical two electrode cell was constructed, which endows maximum cell capacity of 45C/g (12.5mAh/g) that is equivalent to a specific energy of 6.25Wh/kg and a specific power of 522W/kg. This work not only provides a promising electrode for supercapacitor but more importantly demonstrates a unique strategy to design active and durable material for future energy storage technologies.

Large-scale immuno-magnetic cell sorting of T cells based on a self-designed high-throughput system for potential clinical application.

In this contribution, we designed four types of immuno-magnetic nanoparticles for separation of different T cells (CD3+, CD4+, CD8+ and CD14+ T cells), and we established a new large-scale immuno-magnetic cell sorting procedure to achieve an enrichment of particular T cells using our designed auto-IMACS device. This device could achieve recyclable large-scale cell sorting, for which the throughput of the system reached ∼4000 mL and the maximum cell capacity was 4 × 1010. The collected cells were analyzed by flow cytometry and visual cytology data, and the effective selection rates of CD3+, CD4+, CD8+ and CD14+ T cells were 79.3%, 74.1%, 57.1% and 67.9%, respectively. The sorted CD8+ T cells still retained good cytotoxic activity against specific cells. In addition, the sorted T cells can also be further incubated in vitro and proliferated, and even could be infused back into patients for immunotherapy in the near future.

MF 기반 다중 사용자 Massive MIMO 시스템의 최적 기지국 안테나 수 및 사용자 수 분석

본 논문은 다중 사용자 (multiuser) 다중 안테나 (MIMO, multiple-input and multiple-output) 시스템을 기반으로 거대 안테나 시스템 (massive MIMO system)에 대한 성능 분석을 진행한다. 하향 링크 프레임 구조를 고려한 평균 셀 용량을 도출하고, 해당 평균 셀 용량을 기지국 안테나 수 및 사용자 수에 대하여 분석한다. 평균 셀 용량은 기지국 안테나 수 및 사용자 수에 대해 오목 함수 (concave function)이며 이러한 특징을 통해 최적의 기지국 안테나 수 및 사용자 수를 도출한다. 실험 결과를 통해 수식적으로 도출한 최적 안테나 수 및 사용자 수는 실험을 통한 최적 값과 일치함을 확인하였으며 도출한 최적 값을 통해 최대 값의 평균 셀 용량을 얻을 수 있음을 확인할 수 있다. In this paper, we analyze a performance of multiuser massive multiple-input and multiple-output (MIMO) system. We derive the ergodic cell capacity based on a downlink frame structure and analyze the ergodic cell capacity with respect to the number of base station (BS) antennas and the number of users. This paper shows that the ergodic cell capacity is a concave function with respect to the number of BS antennas and the number of users, and also derives the optimal numbers of BS antennas and users for the maximum cell capacity. The simulation results verify the derived analyses and show that the derived numbers of BS antennas and users provide the maximum cell capacity.

Impact of other-cell interferences on downlink capacity in WCDMA Network

Before the establishment of the UMTS network, operators are obliged to make the planning process to ensure a better quality of service (QOS) for mobile stations belonging to WCDMA cells. This process consists of estimating a set of parameters characterizing the radio cell in the downlink direction. Among them, we are interested in the Node B total required power PTot, and the maximum cell capacity, in the case of voice only and in the case of voice/video. To implement the effect of the other-cell interferences power, modeled as a fraction fDL of the own-cell received power, on various radio parameters described previously, we focused our study on two different scenarios: the first is based on an isolated cell and the second, on multiple cells. In addition, when the WCDMA cell reaches its maximum capacity, the introduction of admission control algorithms is essential to maintain the QOS of the ongoing mobile stations. For this purpose, we have proposed an admission control algorithm, based both on the Node B total required power and the cell loading factor. This algorithm gives rigorous results compared to the existing ones in the literature.

Influence of Cathode Active Materials Obtained by a Wet-type Jet Mill on Lithium Cell Performance

We prepared slurries by dispersing LiMn2O4 and LiCoO2 into toluene or NaPO3 aqueous solution. The slurries were then milled with a high-pressure wet-type jet mill to form fine particles. In estimating the performance of Li cells containing the materials, we found that the cell capacity improved with a decrease in the materials' particle size. Maximum cell capacity was obtained using materials produced by milling NaPO3 slurry to reduce the particle diameter to 2-3 μm. We also found that the cell cycle life tended to increase with a decrease in the mean diameter of the material particles.

Effect of cathode active materials produced by a wet-type jet mill on lithium cell performance

Abstract We prepared slurries by dispersing LiMn 2 O 4 and LiCoO 2 into toluene or NaPO 3 aqueous solution. The slurries were then milled with a high-pressure wet-type jet mill to form fine particles. In estimating the performance of Li cells containing the materials, we found that the cell capacity improved with a decrease in the materials’ particle size. Maximum cell capacity was obtained using materials produced by milling NaPO 3 slurry to reduce the particle diameter to 2–3 μm. Such the maximum value was disappeared by treating the materials with toluene. The treatment, however, did not provide remarkable increase in the cell capacity. We found that the cell cycle life tended to increase with a decrease in the mean diameter of the material particles.

Performance analysis of WCDMA wireless access standard

Based on the transmitting power of a mobile station and the maximum cell capacity, the analysis of a wide-band code-division multiple access (WCDMA) standard and the comparison of the corresponding parameters with CDMA2000 or evolution-data only (EV-DO) are given in this paper. The result proves that the mobile station of WCDMA cannot provide the required transmitting power on the specified frequency band and data rate, and the symmetrical capacity in an up-downlink cannot meet the requirement of a mobile Internet. It is questionable for the International Telecommunication Union (ITU) to select the frequency band of 2 GHz for vehicular mobile telecommunication and unreasonable to distribute it over the downlink and uplink channels symmetrically. Only CDMA2000 1X EV-DO or enhanced data rate for GSM evolution (EDGE), which adopts the Time Division Multiple Access (TDMA) mode, can provide the high-speed data rate for a wireless access.

Materials balance in primary batteries. IV. Lithium batteries with organic electrolytes

Part IV of the study of the materials balance in primary batteries concerns the application of the optimization procedure, developed for lithium inorganic batteries, to systems using organic electrolytes. The stoichiometric characteristics of discharge reactions (k1 andk3) were defined for six different lithium battery systems and the cathode discharge characteristics (k2) were determined on the basis of the experimental data reported by various authors. These characteristics were then applied in the optimization procedure developed earlier to predict the maximum cell capacity obtainable at low discharge rates. The values predicted were compared with those reported by various authors; this suggests the magnitude of improvement possible with each of the systems if the present optimization procedure were applied. A good agreement was found between the predicted and the previously reported values for some systems (e.g. Li/CuO), while some other systems showed room for improvement. The optimization procedure was found inapplicable without modifications to one of the systems studied (Li/SO2) due to the limitations in the volume available for the electrolyte.

Materials balance in primary batteries. III. Computer aided design for standard size lithium — thionyl chloride high power cells

The study was continued of the design characteristics of high power type batteries made with the lithium/thionyl chloride system. A computer programme flow chart is presented for solving the system of equations correlating all the dimensions of cell components for any selected cell size. Various cell designs are presented for the three standard cell sizes, AA, C and D showing the effect of the geometry of the cell components on the resultant cell capacity. An optimized cell design is suggested for each particular discharge rate required. As a result of the optimization of the electrode structure, a substantial improvement in the maximum cell capacity was obtained with all three cell sizes.

Materials balance in primary batteries. II. Lithium inorganic batteries at high discharge rates

A study was continued of the design characteristics and optimization procedures leading to an improvement of the maximum cell capacity obtainable with the high power type lithium inorganic batteries. The general relations derived for the low power type cells have been modified for use in the design of the high power type cells. A materials balance was established for the interior components of cylindrical cells made for high discharge rates.

Materials balance in primary batteries. I. Lithium inorganic cells at low discharge rates

A study has been made of the design characteristics and optimization procedures leading to an improvement in the maximum cell capacity obtainable with standard size lithium cells at low discharge rates. General relations have been derived between the cell capacity and the porosity of carbon cathode structures at various stages of cell discharge, based on a cell reaction mechanism proposed earlier. A total materials balance relation has been established for the components involved in the cell reaction in cylindrical cells made for a long range application.