Multipoint System Research Articles

Base Station Selection for Per-cell Precoding with Limited Feedback in Cooperative Multi-point Systems

Though per-cell precoding is an efficient coordinated multipoint transmission/reception transmission mode for frequency-division duplex systems, it has the problems of channel feedback and computational complexity. Especially, when base station has large antennas, these problems are worsened. To overcome these drawbacks, we propose a base station selection precoding that searches an optimal combination of cooperative base stations. By selecting transmission mode at each base station, the feedback overhead and complexity can be relieved and user can acquire additional throughput gains. Also, the analytical approximation of proposed scheme is derived. Simulation results show that the base station precoding has a higher throughput gains in the large antennas environment than conventional schemes and the analytical results approximate the numerical results well.

Hardware-software and algorithmic provision of multipoint systems for long-term monitoring of dynamic processes

An example of information-measuring systems for climate monitoring and operational control of energy resources consumption of the university campus that is functioning in the Altai State Technical University since 2009. The advantages of using such systems for studying various physical processes are discussed. General principles of construction of similar systems, their software, hardware and algorithmic support are considered. It is shown that their fundamental difference from traditional SCADA - systems is the use of databases for storing the results of the observation with a specialized data structure, and by preprocessing of the input signal for its compression. Another difference is the absence of clear criteria for detecting the anomalies in the time series of the observed process. The examples of algorithms that solve this problem are given.

Active magnetic levitation guide based on magnetic damping control

With the application of active magnetic levitation technology, flutter is a problem in the planar multi-point support system, which reduces the bearing capacity and the control precision, and it is difficult to apply advanced control strategies. Therefore, a new method called magnetic damping control is proposed to solve the flutter problem, which can make active magnetic levitation guide to run smoothly.

Multipoint NIR spectroscopy for simultaneous analyses of dairy products – Part B: Quantification

This article constitutes the second part of the study multipoint NIR spectroscopy for simultaneous analyses of dairy products. The overall purpose was to assess the suitability of a multipoint NIR approach as an on/in-line tool for simultaneous monitoring of various quality control parameters. In this part, a multipoint NIR system capable of recording 4 spectra concurrently was tested for simultaneous casein determinations of casein-lactose blends. To this end, spectral acquisition was performed so that two sample blends were scanned at a time. Evaluation of the concurrently-recorded spectra together with the partial least squares (PLS) results demonstrated that the system holds potential for simultaneous compositional analysis of dairy powders.

Cooperative Channel Estimation for Coordinated Transmission With Limited Backhaul

Obtaining accurate global channel state information (CSI) at multiple transmitter devices is critical to the performance of many coordinated transmission schemes. Practical CSI local feedback often leads to noisy and partial CSI estimates at each transmitter. With rate-limited bi-directional backhaul, transmitters have the opportunity to exchange few CSI-related bits to establish global channel state information at transmitter (CSIT). This paper investigates possible strategies toward this goal. We propose a novel decentralized algorithm that produces minimum mean square error-optimal global channel estimates at each device from combining local feedback and information exchanged through backhauls. The method adapts to arbitrary initial information topologies and feedback noise statistics and can do that with a combination of closed-form and convex approaches. Simulations for coordinated multi-point transmission systems with two or three transmitters exhibit the advantage of the proposed algorithm over conventional CSI exchange mechanisms when the coordination backhauls are limited.

Design and Application of Wireless Sensor Network Monitoring Software Based on LABVIEW

Wireless multi-point real-time environmental monitoring system based on LabVIEW is composed of three parts: wireless environment information collection node, communication gateway, and host computer monitoring system. The purpose of this study is to explore the application of wireless monitoring technology in industry. Since that it is at the stage of research feasibility, various sensors used for the applications select the level limited to the ordinary teaching using sensor. AGV uses vehicle manipulator developed by Wuhan Depushi Technology Company and some sensors are simulated. The results of simple basic experiments showed that the wireless module can achieve point to multipoint communication. It is concluded that the monitoring interface can simultaneously process the data of a simulated pipeline terminal node with a simulated AGV data and make them work in a closed loop state.

Beamforming vector design for regenerative wired two‐way relay systems

A new structure for a regenerative two-way relay (TWR) system, called a wired TWR (WTWR) system is introduced. The WTWR consists of two relay nodes that are connected through an optical link, and it operates as a single conventional TWR node. For the WTWR system, beamforming vectors maximising the sum rate of two source/destination nodes (i.e. users) are designed. The WTWR exploiting the proposed beamforming is applicable to various systems that can employ a TWR protocol, such as heterogeneous networks, distributed antenna systems, and coordinated multipoint transmission systems.

Capacity Analysis of Joint Transmission CoMP With Adaptive Modulation

Joint transmission (JT)-based Coordinated Multipoint (CoMP) systems achieve high performance gains by allowing full coordination among multiple cells, transforming unwanted intercell interference into useful signal power. In this paper, we present an analytical model to perform adaptive modulation for a typical JT CoMP system, consisting of three transmission points, under a target bit error rate (BER) constraint. Probability density functions of the signal-to-interference-plus-noise ratio (SINR) are derived for different JT CoMP schemes, and based on them, closed-form expressions for the average spectral efficiency (ASE) are obtained when adopting continuous-rate adaptive modulation. The study of ASE is also extended for the case of discrete-rate modulations, where the performance comparison of different practical quantized modulation schemes is carried out.

Optimal base stations planning for Coordinated Multi-Point system

Through decreasing inter-cell interferences, CoMP (Coordinated Multi-Point) can enhance system capacity and spectral efficiency of cell-edge users significantly. BSs (Base stations) are the front-end accesses of CoMP and their planning influences the overall performance of the system directly. Different from the traditional cellular network, the coverage of BSs in CoMP always overlaps with each other to some degree. In order to investigate the BSs planning for CoMP, this paper builds two optimization models to obtain the location and the number of the BSs. A joint optimization algorithm is proposed to solve models, in which the methodologies of mesh adaptive direct search and successive elimination have been used. Numerical results show that the proposed models can effectively reduce the total transmission power and the number of BSs without losing the quality of service for users, which verifies the effectiveness of the proposed algorithms and the inherent advantage of CoMP.

Double Side Signal Splitting SWIPT for Downlink CoMP Transmissions With Capacity Limited Backhaul

This letter studies power allocation for simultaneous wireless information and power transfer in downlink coordinated multipoint (CoMP) systems. A central unit (CU) conveys data and channel information to multiple radio remote units (RRUs) via a capacity-limited backhaul. We provide a dual polarized (DP) antenna-based double side signal splitting method. Specifically, signals are split up into information decoding part [user equipment (UE) data transmitted from CU] and energy harvesting part (deterministic data created at RRUs), which are transmitted and received via vertical and horizontal polarizations of DP antennas, respectively. Normal beamformers (such as zero forcing and maximum ratio transmission) are used to reduce complexity. The problem is to maximize the sum rate satisfying per-UE received power, per-backhaul-link capacity, and per-RRU power transmission constraints. The results are provided to verify the effectiveness of the proposed scheme.

Knee Joint Proprioception and Quadriceps Muscle Strength among Diabetic and Non Diabetic Subjects

Background: Diabetes mellitus is a group of metabolic disorders characterized by increased blood sugar (glucose) levels (hyperglycemia) with absolute/relative deficiency in carbohydrate, protein and fat metabolism caused by defect in insulin secretion, action of insulin or both. Diabetes mellitus can be combined with problems/impairments which can lead to the decrease in muscles strength and proprioception specially, in the lower limbs. The purpose of the study is to investigate the knee joint repositioning accuracy as a measure of knee joint proprioception and peak torque of the quadriceps muscle as a measure of quadriceps strength between type II diabetic patients (in the first five years of the disease) and healthy subjects.Methods: Thirty male subjects aged between 35–55 years old were included in this study; they were assigned into two equal groups, the study group which included15 type II diabetic patients in early five years of the disease and the control group which included 15 healthy subjects. Active knee joint repositioning accuracy as a measure of knee joint proprioception and the isokinetic peak torque of the quadriceps muscle as a measure of quadriceps strength were measured for both groups by Biodex multipoint system, pro Isokinetic dynamometer.Results: The unpaired t test results between the two groups showed no significant differences in knee joint repositioning errors where P-value was (0.319) and also there was no significant difference in quadriceps muscle strength between the control and study groups where the P-value was (0.157).Conclusion: Knee joint repositioning accuracy and quadriceps muscle strength aren't affected in type II diabetes mellitus patients in early five years of the disease.

A Method for Estimating the Synchronization of a Mild Multipoint Synchronous Initiation Circuit

ABSTRACTMultipoint synchronous initiation has widespread applications in the aerospace and defense fields. However, dispersion is always present in the function time of multipoint synchronous initiation systems. This dispersion could significantly affect weapon efficiency or aerospace mission success; as a result, determining how to estimate and control the function time dispersion of multipoint initiation systems makes considerable sense. In this work, a method for estimating the synchronization of a mild multipoint synchronous initiation circuit was proposed. This method is based on the calculations of detonation velocity dispersion and interface propagating time dispersion from the dispersion relationship and the experimental results of “one input, two outputs” initiation circuits. The obtained estimation of the synchronization of a higher level multipoint initiation circuit coincides well with the experiment test result. The good coincidence shows that the method proposed in this work can be used to predict the synchronization of mild multipoint initiation circuits.

Optimal use of buffer volumes for the measurement of atmospheric gas concentration in multi-point systems

Abstract. Accurate multi-point monitoring systems are required to derive atmospheric measurements of greenhouse gas concentrations both for the calculation of surface fluxes with inversion transport models and for the estimation of non-turbulent components of the mass balance equation (i.e. advection and storage fluxes) at eddy covariance sites. When a single analyser is used to monitor multiple sampling points, the deployment of buffer volumes (BVs) along sampling lines can reduce the uncertainty due to the discrete temporal sampling of the signal. In order to optimize the use of buffer volumes we explored various set-ups by simulating their effect on time series of high-frequency CO2 concentration collected at three Fluxnet sites. Besides, we proposed a novel scheme to calculate half-hourly weighted arithmetic means from discrete point samples, accounting for the probabilistic fraction of the signal generated in the averaging period. Results show that the use of BVs with the new averaging scheme reduces the mean absolute error (MAE) up to 80 % compared to a set-up without BVs and up to 60 % compared to the case with BVs and a standard, non-weighted averaging scheme. The MAE of CO2 concentration measurements was observed to depend on the variability of the concentration field and on the size of BVs, which therefore have to be carefully dimensioned. The optimal volume size depends on two main features of the instrumental set-up: the number of measurement points and the time needed to sample at one point (i.e. line purging plus sampling time). A linear and consistent relationship was observed at all sites between the sampling frequency, which summarizes the two features mentioned above, and the renewal frequency associated with the volume. Ultimately, this empirical relationship can be applied to estimate the optimal volume size according to the technical specifications of the sampling system.

Development of a Multi-Point Injection System Operating on Superheated Alcohol Fuels and Evaluation of Toxicity of Their Combustion Products

This article is devoted to the development of a fuel injection system for internal combustion engines (ICEs or engines) with positive ignition, which operates on superheated fuels. Such systems allow engines securely starting and working on absolute (96%) alcohol, even in low temperature environments. This article describes the operation principle of a multi-point superheated fuels injection system; and the comparison analysis of thermal efficiency and heat balances of both the baseline gasoline engine and the engine with a developed superheated alcohol-based fuel injection system is provided. In experimental studies, the contents of CO, CH, and CO 2 in the combustion products of alcohols were determined. Based on the obtained results we can conclude that the application of the proposed multi-point injection system operating on superheated alcohol fuels reduces both greenhouse gas emissions and harmful substances in exhaust gas emissions.

An Improved Beamforming Schemes in Coordinated Multi-Point Systems

An Improved Beamforming Schemes in Coordinated Multi-Point Systems

On Fair Resource Sharing in Downlink Coordinated Multi-Point Systems

An opportunistic scheduling scheme is proposed for the downlink of a coordinated multi-point (CoMP) system, which exploits both spatial multiplexing and multiuser diversity gains while maintaining fair resource sharing among users. The proposed scheduling scheme consists of two steps in each time slot: selecting a base station (BS) at each user, and then selecting a user at each BS. Although the proposed scheme selects users in a distributed manner, the channels among the selected users are proved to be orthogonal when the number of users approaches infinity. Simulation results demonstrate that the proposed scheme yields a better throughput than the existing scheduling schemes designed for fair resource sharing in CoMP systems.

Design and Analysis of Multi-Point System for Forming Three Dimensional Free-Form Surfaces

Multi-point Sheet metal forming is a flexible technique in which a discrete punches are used to generate the continuous 3-D surface . The proposed die comprises a set of matrices of a closely stacked discrete punches arranged to form a cavity in which a free form surface can be formed .The working surface of the multi-point die are modeled by a uniform B-spline and constructed by adjusting the height of each punch manually. Finite element simulation for the process was performed to study the effect of punch number on the shape error and thickness variation. Experimental work include the building of multi-point die to form the aluminum sheets. The effect using rubber interpolators on dimpling defect were also studied . The results revealed that thickness variation error between the numerical and experimental results is equal to 5% .

Dynamic Energy Management for Smart-Grid-Powered Coordinated Multipoint Systems

Due to increasing threats of global warming and climate change concerns, green wireless communications have recently drawn intense attention toward reducing carbon emissions. Aligned with this goal, the present paper deals with dynamic energy management for smart-grid powered coordinated multipoint (CoMP) transmissions. To address the intrinsic variability of renewable energy sources, a novel energy transaction mechanism is introduced for grid-connected base stations that are also equipped with an energy storage unit. Aiming to minimize the expected energy transaction cost while guaranteeing the worst-case users’ quality of service, an infinite-horizon optimization problem is formulated to obtain the optimal downlink transmit beamformers that are robust to channel uncertainties. Capitalizing on the virtual-queue-based relaxation technique and the stochastic dual-subgradient method, an efficient online algorithm is developed yielding a feasible and asymptotically optimal solution. Numerical tests with synthetic and real data corroborate the analytical performance claims and highlight the merits of the novel approach.

Cooperative Energy Trading in CoMP Systems Powered by Smart Grids

This paper studies the energy management in coordinated multipoint (CoMP) systems powered by smart grids, where each base station (BS) with local renewable energy generation is allowed to implement two-way energy trading with the grid. Due to the uneven renewable energy supply and communication energy demand over distributed BSs, as well as the difference in the prices for their buying/selling energy from/to the grid, it is beneficial for the cooperative BSs to jointly manage their energy trading with the grid and energy consumption in CoMP-based communication for reducing the total energy cost. Specifically, we consider the downlink transmission in one CoMP cluster by jointly optimizing the BSs' purchased/sold energy units from/to the grid and their cooperative transmit precoding to minimize the total energy cost subject to the given quality-of-service (QoS) constraints for the users. First, we obtain the optimal solution to this problem by developing an algorithm based on techniques from convex optimization and uplink–downlink duality. Next, we propose a suboptimal solution of lower complexity than the optimal solution, where zero-forcing (ZF)-based precoding is implemented at the BSs. Finally, through extensive simulations, we show the performance gain achieved by our proposed joint energy trading and communication cooperation schemes in terms of energy cost reduction, as compared with conventional schemes that separately design communication cooperation and energy trading.

On the Performance of Opportunistic NOMA in Downlink CoMP Networks

In this letter, an opportunistic NOMA (ONOMA) scheme is proposed in a coordinated multipoint (CoMP) system. Compared with the conventional joint-transmission (JT) NOMA in CoMP, the main purpose of the ONOMA scheme is to advance the capability of the CoMP system and the effectiveness of the successive-interference-cancellation (SIC) decoding process. The relationship between the topology of the ONOMA cells and the sum-rate of CoMP network is analyzed. Meanwhile, the outage probability of ONOMA system is derived and evaluated in an ideal case and nonideal case, respectively. In the numerical results, the sum-rate and the outage performance of the proposed ONOMA CoMP are compared with the JT-NOMA CoMP and it is shown that the proposed ONOMA scheme outperforms the conventional JT-NOMA scheme in CoMP system.