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.

Coexistence Studies between Mobile Communication Systems and Broadcasting Systems

2013 ◽  
Vol 303-306 ◽  
pp. 2022-2026
Author(s):  
Zheng Rong Xiao ◽  
Li Yun Zhang ◽  
Jun Liao ◽  
Bin Feng Yan
Keyword(s):  
Mobile Communication ◽  
Communication Systems ◽  
Rapid Development ◽  
Base Station ◽  
Mobile Internet ◽  
Mobile System ◽  
High Data ◽  
Mobile Base Station ◽  
Simulation Results ◽  
Mobile Base

With the rapid development of mobile internet, more and more frequency band will be needed to meet the requirement of high data speed. The system coexistence between mobile system and broadcast system is studied, including the scenarios, models, simulation results, related analysis, and finally the solution to resolve the coexistence is given. In urban, an additional 37dB isolation between broadcast system and mobile base station should been satisfied. And an additional 15.7dB is needed between mobile base station and broadcast receiver.

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.

Supplemental material: Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer

2020 ◽  
Author(s):  
Timothy D. Scheibe ◽  
Yilin Fang ◽  
Christopher J. Murray ◽  
Eric E. Roden ◽  
Jinsong Chen ◽  
...  
Keyword(s):  
File Size ◽  
Material Transport ◽  
Heterogeneous Aquifer ◽  
Simulation Results

Geosphere, June 2006, v. 2, p. 220-235, doi: 10.1130/GES00029.1. Animation 1 - Animation of simulation results for U(VI) contamination period (22 yr) for the Geophys2 case. Upper panel—sorbed U(VI); lower panel—aqueous U(VI). All concentrations are in molar units (M). The file size is 1.4 MB.

Supplemental material: Transport and biogeochemical reaction of metals in a physically and chemically heterogeneous aquifer

2020 ◽  
Author(s):  
Timothy D. Scheibe ◽  
Yilin Fang ◽  
Christopher J. Murray ◽  
Eric E. Roden ◽  
Jinsong Chen ◽  
...  
Keyword(s):  
File Size ◽  
Material Transport ◽  
Heterogeneous Aquifer ◽  
Simulation Results

Geosphere, June 2006, v. 2, p. 220-235, doi: 10.1130/GES00029.1. Animation 1 - Animation of simulation results for U(VI) contamination period (22 yr) for the Geophys2 case. Upper panel—sorbed U(VI); lower panel—aqueous U(VI). All concentrations are in molar units (M). The file size is 1.4 MB.

scholarly journals Evasion guidance for air-breathing hypersonic vehicles against unknown pursuer dynamics

2021 ◽  
Author(s):  
Tian Yan ◽  
Yuanli Cai ◽  
Bin Xu
Keyword(s):  
Parameter Estimation ◽  
Gradient Descent ◽  
Rapid Development ◽  
Energy Optimization ◽  
Hypersonic Vehicles ◽  
Air Breathing ◽  
Related Research ◽  
Practical Guidance ◽  
Simulation Results ◽  
Guidance Algorithm

AbstractThe rapid development of hypersonic vehicles has motivated the related research dramatically while the evasion of the hypersonic vehicles becomes one of the challenging issues. Different from the work based on the premise that the pursuers’ information is fully known, in this paper the evasion guidance for air-breathing hypersonic vehicles (AHVs) against unknown pursuer dynamics is studied. The gradient descent is employed for parameter estimation of the unknown dynamics of the pursuer. The energy-optimized evasion guidance algorithm is further developed by taking the acceleration constraint and energy optimization into consideration. Under the proposed algorithm, the system can deal with the unknown pursuer dynamics effectively and provide more practical guidance for the evasion process. The simulation results show that the proposed method can enable the AHV to achieve successful evasion.

scholarly journals Massive MIMO: Achievable Energy Efficiency for 5G systems with Multi-user Environment

2019 ◽  
Vol 8 (2) ◽  
pp. 6527-6534
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Path Loss ◽  
Antenna System ◽  
Base Station ◽  
Small Cells ◽  
Limiting Factors ◽  
Improve Energy Efficiency ◽  
User Terminal ◽  
Simulation Results

Massive Multi-Input and Multi-Output (MIMO) antenna system potentially provides a promising solution to improve energy efficiency (EE) for 5G wireless systems. The aim of this paper is to enhance EE and its limiting factors are explored. The maximum EE of 48 Mbit/Joule was achieved with 15 user terminal (UT)s. This problem is related to the uplink spectral efficiency with upper bound for future wireless networks. The maximal EE is obtained by optimizing a number of base station (BS) antennas, pilot reuse factor, and BSs density. We presented a power consumption model by deriving Shannon capacity calculations with closed-form expressions. The simulation result highlights the EE maximization with optimizing variables of circuit power consumption, hardware impairments, and path-loss exponent. Small cells achieve high EE and saturate to a constant value with BSs density. The MRC scheme achieves maximum EE of 36 Mbit/Joule with 12 UTs. The simulation results show that peak EE is obtained by deploying massive BS antennas, where the interference and pilot contamination are mitigated by coherent processing. The simulation results were implemented by using MATLAB 2018b.

scholarly journals Low-to-Zero-Overhead IRS Reconfiguration: Decoupling Illumination and Channel Estimation

2021 ◽  
Author(s):  
Vahid Jamali
Keyword(s):  
Phase Shift ◽  
Channel Estimation ◽  
Wireless Systems ◽  
Mobile User ◽  
Base Station ◽  
Channel State ◽  
Major Bottleneck ◽  
Reconfiguration Overhead ◽  
Reflecting Surfaces ◽  
Special Case

Most algorithms developed so far for the optimization of Intelligent Reflecting Surfaces (IRSs) require knowledge of full Channel State Information (CSI). However, the resulting acquisition overhead constitutes a major bottleneck for the realization of IRS-assisted wireless systems in practice. In contrast, in this paper, focusing on downlink transmissions from a Base Station (BS) to a Mobile User (MU) that is located in a blockage region, we propose to optimize the IRS for illumination of the area centered around the MU. Hence, the proposed design requires the estimation of the MU’s position and not the full CSI. For a given IRS phase-shift configuration, the end-to-end BS-IRS-MU channel can then be estimated using conventional channel estimation techniques. The IRS reconfiguration overhead for the proposed scheme depends on the MU mobility as well as how wide the coverage of the IRS illumination is. Therefore, we develop a general IRS phase-shift design, which is valid for both the near- and far-field regimes and features a parameter for tuning the size of the illumination area. Moreover, we study a special case where the IRS illuminates the entire blockage area, which implies that the IRS phase shifts do not change over time leading to zero overhead for IRS reconfiguration.

scholarly journals Game-based cache allocation strategy for ICN slicing

2021 ◽  
Vol 336 ◽  
pp. 05030
Author(s):  
Liping Ge ◽  
Jinhe Zhou
Keyword(s):  
Equilibrium Solution ◽  
Base Station ◽  
Virtual Network ◽  
Game Model ◽  
Allocation Strategy ◽  
Newton Iterative Method ◽  
Content Acquisition ◽  
Simulation Results ◽  
Cache Allocation ◽  
Cooperative Game Model

To reduce the delay of content acquisition, this paper proposes a game-based cache allocation strategy in the Information-Centric Network (ICN) slice. The cache resource allocation of different mobile virtual network operators (MVNOs) is modeled as a non-cooperative game model. The Newton iterative method is used to solve this problem, and the cache space allocated by the base station for each MVNO is obtained. Finally, the Nash equilibrium solution is obtained. Simulation results show that the proposed algorithm can reduce the delay.

scholarly journals About estimation of base station output power in GSM like systems under real conditions

2020 ◽  
Vol 30 (1) ◽  
pp. 109-119
Author(s):  
Aleksandar Lebl ◽  
Dragan Mitic ◽  
Zarko Markov ◽  
Verica Vasiljevic
Keyword(s):  
Computer Simulation ◽  
Output Power ◽  
Mobile User ◽  
Base Station ◽  
Cumulative Distribution ◽  
Real Case ◽  
The Real ◽  
The Mean

The output power of traffic channels in one cell of GSM like systems is estimated in this paper. We consider the real case: the number of users is much higher than the number of channels, the output power of one channel depends on the cube of the distance between a mobile user and the base station, and the distribution of users in the cell is uniform. We derive the expressions for cumulative distribution of output power of one channel and for the mean output power of the whole base station. Results of the calculation are confirmed by computer simulation.

scholarly journals SoftPSN: Software-Defined Resource Slicing for Low-Latency Reliable Public Safety Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Anteneh A. Gebremariam ◽  
Muhammad Usman ◽  
Riccardo Bassoli ◽  
Fabrizio Granelli
Keyword(s):  
Public Safety ◽  
First Responders ◽  
Base Station ◽  
Low Latency ◽  
Radio Resource ◽  
Life Saving ◽  
Before And After ◽  
Simulation Results ◽  
Emergency Scenarios ◽  
Safety Applications

Achieving the low-latency constraints of public safety applications during disaster could be life-saving. In the context of public safety scenarios, in this paper, we propose an efficient radio resource slicing algorithm that enables first responders to deliver their life-saving activities effectively. We used the tool of stochastic geometry to model the base station distribution before and after a disaster. In addition, under this umbrella, we also proposed an example of public safety scenario, ultrareliable low-latency file sharing, via in-band device-to-device (D2D) communication. The example scenario is implemented in NS-3. The simulation results show that radio resource slicing and prioritization of first responders resources can ensure ultrareliable low-latency communication (URLLC) in emergency scenarios.

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