scholarly journals An MBS-Assisted Femtocell Transmit Power Control Scheme with Mobile User QoS Guarantee in 2-Tier Heterogeneous Femtocell Networks

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Jenhui Chen ◽  
Chih-Cheng Yang ◽  
Shiann-Tsong Sheu
Keyword(s):  
Technical Problem ◽  
Mobile User ◽  
Base Station ◽  
Femtocell Networks ◽  
Transmit Power ◽  
Downlink Transmission ◽  
Power Adjustment ◽  
Control Scheme ◽  
Major Trend ◽  
Simulation Results

This study investigates how to adjust the transmit power of femto base station (FBS) to mitigate interference problems between the FBSs and mobile users (MUs) in the 2-tier heterogeneous femtocell networks. A common baseline of deploying the FBS to increase the indoor access bandwidth requires that the FBS operation will not affect outdoor MUs operation with their quality-of-service (QoS) requirements. To tackle this technical problem, anFBS transmit power adjustment(FTPA) algorithm is proposed to adjust the FBS transmit power (FTP) to avoid unwanted cochannel interference (CCI) with the neighboring MUs in downlink transmission. FTPA reduces the FTP to serve its femto users (FUs) according to the QoS requirements of the nearest neighboring MUs to the FBS so that the MU QoS requirement is guaranteed. Simulation results demonstrate that FTPA can achieve a low MU outage probability as well as serve FUs without violating the MU QoS requirements. Simulation results also reveal that FTPA has better performance on voice and video services which are the major trend of future multimedia communication in the NGN.

scholarly journals A trade-off between Energy Efficiency and Spectral Efficiency in macro-femtocell networks

2021 ◽  
Author(s):  
Joydev Ghosh
Keyword(s):  
Energy Efficiency ◽  
Spectral Efficiency ◽  
Analytical Framework ◽  
Weighting Factor ◽  
Base Station ◽  
Fine Tuning ◽  
Pareto Optimal ◽  
Femtocell Networks ◽  
Transmit Power ◽  
Trade Off

<div>Obtaining large spectral efficiency (SE) and energy efficiency (EE) subject to quality of experience (QoE) is one of the prime concerns for the wireless next generation networks, however a major confrontation with its trade-off which is becoming apparent while optimizing both SE and EE parameters concurrently. In this work, an analytical framework for a cognitive-femtocell network is proposed to be dealt with and overcome the situations regarded as unwelcome. Here, the conflict of SE-EE trade-off in downlink (DL) transmission is expressed methodically by Pareto Optimal Set (POS) based on a multi-empirical most effective use of a resource scheme as a function of femto base station (FBS) and macro base station (MBS) transmit power and base station (BS) density, respectively. Then, SE and EE are formulated in a utility function by applying Cobb-Douglas production function to transform the multi- mpirical difficulty into the single-empirical optimization case. Besides, it is analytically shown that the SE-EE trade-off can be optimize through a distinctive universal optimum among the Pareto optimal by fine tuning the weighting metric other than BS transmit power and density, respectively. Simulation results validate that it is possible to obtain the EE-SE trade-off with SINR threshold at different weighting factor.</div>

A New SLNR-Based Precoding for Multiuser MIMO Downlinks

2014 ◽  
Vol 644-650 ◽  
pp. 4066-4071
Author(s):  
Xin Min Li
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Base Station ◽  
Semidefinite Relaxation ◽  
Constraint Condition ◽  
Multiuser Mimo ◽  
Power Constraint ◽  
Transmit Power ◽  
Simulation Results

A new SLNR-based precoding is proposed for multiuser MIMO downlinks, which pursues the goal that minimizes total transmit power under each user’s SLNR constraint. The goal problems can be successfully solved by using semidefinite relaxation (SDR) techniques, and power constraint condition added in goal problems can efficiently reduce total transmit power of the base station. Simulation results show that our proposed scheme is almost feasible for users with one antenna, and it has better bit error rate (BER) and lower total transmit power than the maximal-SLNR based precoding method, when it satisfies large SLNR thretholds.

scholarly journals A trade-off between Energy Efficiency and Spectral Efficiency in macro-femtocell networks

2021 ◽  
Author(s):  
Joydev Ghosh
Keyword(s):  
Energy Efficiency ◽  
Spectral Efficiency ◽  
Analytical Framework ◽  
Weighting Factor ◽  
Base Station ◽  
Fine Tuning ◽  
Pareto Optimal ◽  
Femtocell Networks ◽  
Transmit Power ◽  
Trade Off

<div>Obtaining large spectral efficiency (SE) and energy efficiency (EE) subject to quality of experience (QoE) is one of the prime concerns for the wireless next generation networks, however a major confrontation with its trade-off which is becoming apparent while optimizing both SE and EE parameters concurrently. In this work, an analytical framework for a cognitive-femtocell network is proposed to be dealt with and overcome the situations regarded as unwelcome. Here, the conflict of SE-EE trade-off in downlink (DL) transmission is expressed methodically by Pareto Optimal Set (POS) based on a multi-empirical most effective use of a resource scheme as a function of femto base station (FBS) and macro base station (MBS) transmit power and base station (BS) density, respectively. Then, SE and EE are formulated in a utility function by applying Cobb-Douglas production function to transform the multi- mpirical difficulty into the single-empirical optimization case. Besides, it is analytically shown that the SE-EE trade-off can be optimize through a distinctive universal optimum among the Pareto optimal by fine tuning the weighting metric other than BS transmit power and density, respectively. Simulation results validate that it is possible to obtain the EE-SE trade-off with SINR threshold at different weighting factor.</div>

scholarly journals Analysis of an SDN-Based Cooperative Caching Network with Heterogeneous Contents

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1491
Author(s):  
Qi Li ◽  
Xiaoxiang Wang ◽  
Dongyu Wang ◽  
Yibo Zhang ◽  
Yanwen Lan ◽  
...  
Keyword(s):  
Rapid Development ◽  
Mobile User ◽  
Base Station ◽  
Cooperative Caching ◽  
Software Defined Network ◽  
File Size ◽  
Caching Strategy ◽  
Content Caching ◽  
Data Coverage ◽  
Simulation Results

The ubiquity of data-enabled mobile devices and wireless-enabled data applications has fostered the rapid development of wireless content caching, which is an efficient approach to mitigating cellular traffic pressure. Considering the content characteristics and real caching circumstances, a software-defined network (SDN)-based cooperative caching system is presented. First, we define a new file block library with heterogeneous content attributes [file popularity, mobile user (MU) preference, file size]. An SDN-based three-tier caching network is presented in which the base station supplies control coverage for the entire macrocell and cache helpers (CHs), MUs with cache capacities offer data coverage. Using the ‘most popular content’ and ‘largest diversity content’, a distributed cooperative caching strategy is proposed in which the caches of the MUs store the most popular contents of the file block library to mitigate the effect of MU mobility, and those of the CHs store the remaining contents in a probabilistic caching manner to enrich the content diversity and reduce the MU caching pressure. The request meet probability (RMPro) is subsequently proposed, and the optimal caching distribution of the contents in the probabilistic caching strategy is obtained via optimization. Finally, using the result of RMPro optimization, we also analyze the content retrieval delays that occur when a typical MU requests a file block or a whole file. Simulation results demonstrate that the proposed caching system can achieve quasi-optimal revenue performance compared with other contrasting schemes.

Model development and control of an auto-refrigerated polystyrene polymerization reactor

2021 ◽  
pp. 014233122110251
Author(s):  
Reyhane Mokhtarname ◽  
Ali Akbar Safavi ◽  
Leonhard Urbas ◽  
Fabienne Salimi ◽  
Mohammad M Zerafat ◽  
...  
Keyword(s):  
Temperature Control ◽  
Model Development ◽  
Heat Removal ◽  
Superior Performance ◽  
Polymerization Process ◽  
Vacuum System ◽  
Control Scheme ◽  
Simulation Results ◽  
And Control ◽  
Operating Plant

Dynamic model development and control of an existing operating industrial continuous bulk free radical styrene polymerization process are carried out to evaluate the performance of auto-refrigerated CSTRs (continuous stirred tank reactors). One of the most difficult tasks in polymerization processes is to control the high viscosity reactor contents and heat removal. In this study, temperature control of an auto-refrigerated CSTR is carried out using an alternative control scheme which makes use of a vacuum system connected to the condenser and has not been addressed in the literature (i.e. to the best of our knowledge). The developed model is then verified using some experimental data of the real operating plant. To show the heat removal potential of this control scheme, a common control strategy used in some previous studies is also simulated. Simulation results show a faster dynamics and superior performance of the first control scheme which is already implemented in our operating plant. Besides, a nonlinear model predictive control (NMPC) is developed for the polymerization process under study to provide a better temperature control while satisfying the input/output and the heat exchanger capacity constraints on the heat removal. Then, a comparison has been also made with the conventional proportional-integral (PI) controller utilizing some common tuning rules. Some robustness and stability analyses of the control schemes investigated are also provided through some simulations. Simulation results clearly show the superiority of the NMPC strategy from all aspects.

CONTROLLING THE UNCERTAIN MULTI-SCROLL CRITICAL CHAOTIC SYSTEM WITH INPUT NONLINEAR USING SLIDING MODE CONTROL

2009 ◽  
Vol 23 (16) ◽  
pp. 2021-2034 ◽  
Author(s):  
XINGYUAN WANG ◽  
DA LIN ◽  
ZHANJIE WANG
Keyword(s):  
Chaotic System ◽  
Sliding Mode ◽  
Equilibrium Points ◽  
Dead Zone ◽  
Variable Structure ◽  
Sliding Mode Controller ◽  
Global Stabilization ◽  
Structure Control ◽  
Control Scheme ◽  
Simulation Results

In this paper, control of the uncertain multi-scroll critical chaotic system is studied. According to variable structure control theory, we design the sliding mode controller of the uncertain multi-scroll critical chaotic system, which contains sector nonlinearity and dead zone inputs. For an arbitrarily given equilibrium point of the uncertain multi-scroll chaotic system, we achieve global stabilization for the equilibrium points. Particularly, a class of proportional integral (PI) switching surface is introduced for determining the convergence rate. Furthermore, the proposed control scheme can be extended to complex multi-scroll networks. Finally, simulation results are presented to demonstrate the effectiveness of the proposed control scheme.

scholarly journals Prediction-based association control scheme in dense femtocell networks

PLoS ONE ◽  
2017 ◽  
Vol 12 (3) ◽  
pp. e0174220 ◽  
Author(s):  
Nak Woon Sung ◽  
Ngoc-Thai Pham ◽  
Thong Huynh ◽  
Won-Joo Hwang ◽  
Ilsun You ◽  
...  
Keyword(s):  
Femtocell Networks ◽  
Control Scheme

A Robust Trajectory Tracking Control Scheme of Two-Link Flexible Manipulator

2011 ◽  
Vol 328-330 ◽  
pp. 2108-2112
Author(s):  
Jing Shuang Lu ◽  
Chun Mei Du ◽  
Rui Zhou ◽  
Na Li
Keyword(s):  
Trajectory Tracking ◽  
Tracking Control ◽  
Vertical Plane ◽  
Flexible Manipulator ◽  
System Model ◽  
Error Signal ◽  
Dynamics Model ◽  
Trajectory Tracking Control ◽  
Control Scheme ◽  
Simulation Results

A simple dynamics model is established based on the two-link flexible manipulator moving within the vertical plane, and a robust simple control scheme is put forward. The advantages of this scheme are simple and good robustness. Only the error signal is needed when designing the control scheme and the acquirement of control signal does not depend on the system model. The simulation results show that this method has a good robustness and stability.

Iterative learning algorithm with a quadratic criterion for linear time-varying systems

2002 ◽  
Vol 216 (3) ◽  
pp. 309-316 ◽  
Author(s):  
S N Huang ◽  
K K Tan ◽  
T H Lee
Keyword(s):  
Learning Algorithm ◽  
Linear Time ◽  
Tracking Error ◽  
Iterative Learning ◽  
Tracking Performance ◽  
Time Varying ◽  
Control Scheme ◽  
Time Varying Systems ◽  
Simulation Results ◽  
Learning Law

A novel iterative learning controller for linear time-varying systems is developed. The learning law is derived on the basis of a quadratic criterion. This control scheme does not include package information. The advantage of the proposed learning law is that the convergence is guaranteed without the need for empirical choice of parameters. Furthermore, the tracking error on the final iteration will be a class K function of the bounds on the uncertainties. Finally, simulation results reveal that the proposed control has a good setpoint tracking performance.

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