scholarly journals Deployment of Clustered-Based Small Cells in Interference-Limited Dense Scenarios: Analysis, Design, and Trade-Offs

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
David Alejandro Urquiza Villalonga ◽  
Felip Riera-Palou ◽  
M. Julia Fernández-Getino García ◽  
Guillem Femenias

Network densification is one of the most promising solutions to address the high data rate demands in 5G and beyond (B5G) wireless networks while ensuring an overall adequate quality of service. In this scenario, most users experience significant interference levels from neighbouring mobile stations (MSs) and access points (APs) making the use of advanced interference management techniques mandatory. Clustered interference alignment (IA) has been widely proposed to manage the interference in densely deployed scenarios with a large number of users. Nonetheless, the setups considered in previous works are still far from the densification levels envisaged for 5G/B5G networks that are considered in this paper. Moreover, prior designs of clustered-IA systems relied on oversimplified channel models and/or enforced single-stream transmission. In this paper, we explore an ultradense deployment of small cells (SCs) to provide coverage in 5G/B5G wireless networks. A novel cluster design based on a size-restricted k -means algorithm to divide the SCs into different clusters is proposed taking into account path loss and shadowing effects, thus providing a more realistic solution than those available in the current literature. Unlike previous works, this clustering method can also cater for spatial multiplexing scenarios. Also, several design parameters such as the number of transmit antennas, multiplexed data streams, and deployed APs are analyzed in order to identify trade-offs between performance and complexity. The relationship between density of network elements per area unit and performance is investigated, thus allowing to illustrate that there is an optimal coverage area value over which the network resources should be distributed. Moreover, it is shown that the spectral-efficiency degradation due to the intercluster interference in ultradense networks (UDNs) points to the need of designing an interference management algorithm that accounts for both intracluster and intercluster interferences. Simulation results provide key insights for the deployment of small cells in interference-limited dense scenarios.

2021 ◽  
Author(s):  
Mohamed Saeid Shalaby ◽  
Hussein Mohamed Hussein ◽  
Mona Mohamed Sabry Shokair ◽  
Ahmed Mohamed Benaya

Abstract 5G networks and beyond can provide high data rate for the served users. Small cells, massive multiple input multiple outputs (mMIMO) as well as working in millimeter wave bands are emerging tools toward empowering 5G and beyond networks. The cellular mMIMO networks can provide high data rate for users, however their performance is not satisfied for the cell-edge users and shadowed users. Fortunately, the cell-Free mMIMO network can provide a satisfied performance for all users even if they are in shadowed areas or at cell edges. The distributed access points (APs) through the coverage area can allow users to get benefit of the best serving AP. Furthermore, the users can have services anywhere due to the existence of one AP at least. The cell-Free mMIMO networks can provide a high throughput when they are operated in the millimeter wave bands due to the high available bandwidth. The operation in millimeter wave bands can let the 5G networks and beyond have a high data rate. Therefore, this paper gives a great attention to the millimeter wave bands. In this paper, the performance of the cell-Free mMIMO network, operating in the millimeter wave bands, is mathematically evaluated and simulated. The performance can include the spectral efficiency (SE), bit error rate (BER), and energy efficiency (EE). It is observed that the centralized cooperation among the APs, level 4, can provide a high SE and EE even if the maximal ratio combining (MRC) is applied. Moreover, the cell-Free four cooperation levels can perform better than cellular mMIMO when the millimeter wave non-line-of-sight (NLOS) models are applied.


2009 ◽  
Author(s):  
Kostas Stamatiou ◽  
John G. Proakis ◽  
James R. Zeidler

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Steve W. Y. Mung ◽  
Cheuk Yin Cheung ◽  
Ka Ming Wu ◽  
Joseph S. M. Yuen

This article presents a simple wideband rectangular antenna in foldable and non-foldable (printed circuit board (PCB)) structures for Internet of Things (IoT) applications. Both are simple structures with two similar rectangular metal planes which cover multiple frequency bands such as GPS, WCDMA/LTE, and 2.4 GHz industrial, scientific, and medical (ISM) bands. This wideband antenna is suitable to integrate into the short- and long-range wireless applications such as the short-range 2.4 GHz ISM band and standard cellular bands. This lowers the overall size of the product as well as the cost in the applications. In this article, the configuration and operation principle are presented as well as its trade-offs on the design parameters. Simulated and experimental results of foldable and non-foldable (PCB) structures show that the antenna is suited for IoT applications.


2021 ◽  
Vol 11 (13) ◽  
pp. 5934
Author(s):  
Georgios Papaioannou ◽  
Jenny Jerrelind ◽  
Lars Drugge

Effective emission control technologies and novel propulsion systems have been developed for road vehicles, decreasing exhaust particle emissions. However, work has to be done on non-exhaust traffic related sources such as tyre–road interaction and tyre wear. Given that both are inevitable in road vehicles, efforts for assessing and minimising tyre wear should be considered. The amount of tyre wear is because of internal (tyre structure, manufacturing, etc.) and external (suspension configuration, speed, road surface, etc.) factors. In this work, the emphasis is on the optimisation of such parameters for minimising tyre wear, but also enhancing occupant’s comfort and improving vehicle handling. In addition to the search for the optimum parameters, the optimisation is also used as a tool to identify and highlight potential trade-offs between the objectives and the various design parameters. Hence, initially, the tyre design (based on some chosen tyre parameters) is optimised with regards to the above-mentioned objectives, for a vehicle while cornering over both Class A and B road roughness profiles. Afterwards, an optimal solution is sought between the Pareto alternatives provided by the two road cases, in order for the tyre wear levels to be less affected under different road profiles. Therefore, it is required that the tyre parameters are as close possible and that they provide similar tyre wear in both road cases. Then, the identified tyre design is adopted and the optimum suspension design is sought for the two road cases for both passive and semi-active suspension types. From the results, significant conclusions regarding how tyre wear behaves with regards to passenger comfort and vehicle handling are extracted, while the results illustrate where the optimum suspension and tyre parameters have converged trying to compromise among the above objectives under different road types and how suspension types, passive and semi-active, could compromise among all of them more optimally.


2018 ◽  
Vol 6 (1) ◽  
pp. 62-66
Author(s):  
Andari Dyah Widowatie

The problem that often occurs in malls or supermarkets is the use of EDC as a non-cash payment tool for alternative customers. However, the use of EDC machines sometimes experiences problems, namely when customers enter data so that transactions take longer, so this study aims to analyze the optimization of EDC placement in shopping center buildings. This research method is to measure the parameters, namely the RSCP and the closest antenna coverage from the EDC. In this study, three samples were taken, namely Cassa 1, 2 and 3 at Matahari Department Store Malang Town Square. The results of this study were obtained that the Drive Test in the Matahari room showed that Cassa-1, Cassa-2 and Cassa-3 received RSCP with green color which means good. Two of the three tools, namely Drive Test and Mobile can display RSCP with a value that is not too much difference. Especially for EDC is only able to visually display the RSCP and the results of previous calculations, the value of ten antennas which is in the Matahari room has a coverage area below 10 m. And the UG-12 antenna, which is the closest antenna to Cassa-3,  that is outside the antenna coverage, while the UG-08 antenna can still reach the Cassa-3 area. This shows that the placement of EDC has met the requirements to get adequate signal quality and the position of the Cassa table can be moved according to the antenna coverage calculation on the Link budget and Path Loss calculations


2000 ◽  
Author(s):  
S. R. Habibi

Abstract This paper considers the design of a high performance hydrostatic actuation system referred to as the ElectroHydraulic Actuator (EHA). The expected performance of EHA and its dominant design parameters are identified by using mathematical modeling. The design parameters are classified into Direct and Indirect categories based on the measure of their accessibility to the designer. The Direct parameters are directly quantifiable and, can be linked to the performance of EHA through a set of mathematical functions. A prototype of EHA has been produced and described. The mathematical functions linking performance to design parameters are used to investigate design trade-offs. Design improvements to the prototype are suggested by using constrained quadratic programming.


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