scholarly journals Underground Coal Mine Fingerprint Positioning Based on the MA-VAP Method

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5401
Author(s):  
Mingzhi Song ◽  
Jiansheng Qian

The access points (APs) in a coal mine wireless local area network (WLAN) are generally sparsely distributed. It can, with difficulty, satisfy the basic requirements of the fingerprint positioning based on Wi-Fi. Currently, the effectiveness of positioning is ensured by deploying more APs in an underground tunnel, which significantly increases system cost. This problem can be solved by using the Virtual Access Point (VAP) method that introduces virtual access points (VAPs), which can be virtually arranged in any part of the positioning area without installing actual access points. The drawback of the VAP method is that the generated received signal strength (RSS) value of a VAP is calculated based on the mapping of RSS value from only one corresponding access point (AP). This drawback does not consider the correlation between different AP signals and the generated RSS value of a VAP, which makes the modeling of fingerprint samples and real-time RSS collection incomplete. This study proposed a Multi-Association Virtual Access Point (MA-VAP) method takes into account the influence of multi-association. The multi-association coefficient is calculated based on the correlation between the RSS values of a VAP and multiple access points (APs). Then, the RSS value generated by a VAP is calculated using the multi-association function. The real-time collected RSS values from multiple APs related to this VAP are the input of the multi-association function. The influence of the number of VAPs and their arrangement on positioning accuracy is also analyzed. The experimental positioning results show that the proposed MA-VAP method achieves better positioning performance than the VAP method for the same VAP arrangement. Combined with the Weight K-Nearest Neighbors (WKNN) algorithm and Kernel Principal Component Analysis (KPCA) algorithm, the positioning error of the MA-VAP method of the error distance cumulative distribution function (CDF) at 90% is 4.5 m (with WKNN) and 3.5 m (with KPCA) in the environment with non-line-of-sight (NLOS) interference, and the positioning accuracy is improved by 10% (with WKNN) and 22.2% (with KPCA) compared with the VAP method. The MA-VAP method not only effectively solves the fingerprint positioning problem when APs are sparse deployed, but also improves the positioning accuracy.

Author(s):  
Guohua Hu ◽  
Pascal Feldhaus ◽  
Yuwu Feng ◽  
Shengjie Wang ◽  
Juan Zheng ◽  
...  

Collecting data like location information is an essential part of concepts like the “IoT” or “Industry 4.0”. In the case of the development of a precise localization system and an integrated navigation system, indoor location technology receives more and more attention and has become a hot research topic. Common indoor location techniques are mainly based on wireless local area network, radio frequency tag, ZigBee technology, Bluetooth technology, infrared technology and ultra-wideband (UWB). However, these techniques are vulnerable to various noise signals and indoor environments, and also the positioning accuracy is easily affected by the complicated indoor environment. We studied the problem of real-time location tracking based on UWB in an indoor environment in this paper. We have proposed a combinational filtering algorithm and an improved Two-Way Ranging (ITWR) method for indoor real-time location tracking. The simulation results prove that the real-time performance and high accuracy of the presented algorithm can improve location accuracy. The experiment shows that the combinational algorithm and ITWR method which are applied to the positioning and navigation of the smart supermarket, have achieved quiet good results in positioning accuracy. The average positioning error is less than 10[Formula: see text]cm, some of the improvements can elevate the positioning accuracy by 17.5%. UWB is a suitable method for indoor real-time location tracking and has important theoretic value and practical significance.


2019 ◽  
Vol 6 (2) ◽  
pp. 94
Author(s):  
PUTU FEBY PRADIPTA ◽  
GEDE SUKADARMIKA ◽  
I Gst A. KOMANG DIAFARI DJUNI H

The development of information technology in the field of education has developed very rapidly, e-learning is one example of the development of information technology of education. To optimize the e-learning system in an area, adequate network infrastructure is needed. This research aims to improve the WLAN (Wireless Local Area Network) network infrastructure in the campus area of the Electrical Engineering Study Program, Faculty of Engineering, Udayana University, Bukit Jimbaran. This research was conducted in 3 stages, namely measuring the capacity and range of access points directly, calculating the access point signal level, and using simulations to calculate the number and range of access points using the Atoll Rf Planning software. Based on the results of measurements and calculations obtained, the results of the 3 stages of the research carried out found the farthest range of indoor and outdoor access points each 12 meters and 22.6 meters. The total number of access points needed for indoor and outdoor positions as a whole in accordance with the simulation results requires as many as 22 access points.


2016 ◽  
Vol 3 (1) ◽  
pp. 31-39
Author(s):  
F Ammar ◽  
Hanafi Hanafi

WiFi bekerja pada band 2,4 GHz dan 5 GHz. Standar WiFi yang bekerja pada frekuensi ini antara lain IEEE802.11g dan IEEE802.11a. Pada penelitian ini dilakukan pengukuran terhadap transfer rate download dan upload data dengan standar IEEE802.11g dan IEEE802.11a. Pengukuran dilakukan pada kanal Line of Sight (LOS), menggunakan dua buah laptop yang dihubungkan dengan Access Point (AP) standar IEEE802.11g dan IEEE802.11a.  Hasil penelitian diperoleh, pada standar IEEE802.11g, transfer rate download dan upload data tertinggi 2.662,54.KB/s dan 2.549,60 KB/s, dan terendah 484,50.KB/s dan 477,40 KB/s, sedangkan pada standar IEEE802.11a, transfer rate download dan upload data tertinggi 8.104,68 KB/s dan 5.744,24 KB/s, dan terendah 872,24 KB/s dan 465,38.KB/s. Pada standar IEEE802.11g, transfer rate download dan upload data pada sinyal terendah hingga di bawah 35% dan 30%, dari transfer rate download dan upload data tertinggi. Pada standar IEEE802.11a, transfer rate download dan upload data pada kualitas sinyal terendah hingga di bawah 20% dan 30%, dari transfer rate download dan upload data tertinggi. Kemampuan transfer rate download data Standar IEEE802.11a, 2–3 kali lebih baik pada kondisi kualitas sinyal tertinggi, dan tidak lebih dari 2 kali pada kondisi kualitas sinyal terendah, dibandingkan kemampuan transfer rate download data standar IEEE802.11g. Kemampuan transfer rate upload data Standar IEEE802.11a, 1,4–3 kali lebih baik pada kondisi kualitas sinyal tertinggi, dan 1-3 kali lebih baik pada kondisi kualitas sinyal terendah, dibandingkan kemampuan transfer rate upload data standar IEEE802.11g.


2021 ◽  
Vol 8 (2) ◽  
pp. 75-84
Author(s):  
Gusni Amini Siagian ◽  
Lindawati Lindawati ◽  
Sopian Soim

Wireless Local area Network  (WLAN) suatu jaringan area lokal tanpa kabel yang menggunakan frekuensi radio sebagai media transmisinya. Dalam penelitian ini merancang sebuah jaringan wifi di Perumahan Dosen Politeknik Negeri Sriwijaya, yang pancaran wifinya dari kampus Politeknik Negeri Sriwijaya, sehingga Perumahan Dosen dapat mengakses wifi tanpa perlu datang ke kampus. Sebagai receiver komunikasi wifi diperlukan peranan antena dalam sistem komunikasi tanpa kabel (wireless) dengan jarak jauh, antena yang digunakan adalah antena yagi yang bekerja pada frekuensi 2400 MHz. Antena yagi dipilih karena sifatnya yang directional atau pola pancarannya yang terarah. Dalam perancangan antena yagi untuk ukuran reflector, driven, director dan balun dibantu dengan software yagi calculator serta disimulasikan dan diuji  menggunakan MMANA-GAL untuk menghasilkan parameter antena yang lebih akurat. Antena yagi ini kemudian akan dihubungkan dengan access point yang disetup sebagai client untuk menerima sinyal dari transmitter dan router sebagai proses routing agar user di Perumahan Dosen dapat mengakses wifi tersebut. Berdasarkan hasil pengujian MMANA-GAL antena yagi dengan frekuensi 2400 MHz, diperoleh Standing Wave Ratio (SWR) sebesar 1.16 dan Penguatan (Gain) sebesar 14,59 dB.  


Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 475 ◽  
Author(s):  
Kwo-Ting Fang ◽  
Cheng-Tao Lee ◽  
Li-min Sun

The hierarchical-based structure is recognized as a favorable structure for wireless local area network (WLAN) positioning. It is comprised of two positioning phases: the coarse localization phase and the fine localization phase. In the coarse localization phase, the users’ positions are firstly narrowed down to smaller regions or clusters. Then, a fingerprint matching algorithm is adopted to estimate the users’ positions within the clusters during the fine localization phase. Currently the clustering strategies in the coarse localization phase can be divided into received signal strength (RSS) clustering and 3D clustering. And the commonly seen positioning algorithms in the fine localization phase include k nearest neighbors (kNN), kernel based and compressive sensing-based. This paper proposed an improved WLAN positioning method using the combination: 3D clustering for the coarse localization phase and the compressive sensing-based fine localization. The method have three favorable features: (1) By using the previously estimated positions to define the sub-reference fingerprinting map (RFM) in the first coarse localization phase, the method can adopt the prior information that the users’ positions are continuous during walking to improve positioning accuracy. (2) The compressive sensing theory is adopted in the fine localization phase, where the positioning problem is transformed to a signal reconstruction problem. This again can improve the positioning accuracy. (3) The second coarse localization phase is added to avoid the global fingerprint matching in traditional 3D clustering-based methods when the stuck-in-small-area problem is encountered, thus, sufficiently lowered the maximum positioning latency. The proposed improved hierarchical WLAN positioning method is compared with two traditional methods during the experiments section. The resulting positioning accuracy and positioning latency have shown that the performance of the proposed method has better performance in both aspects.


Author(s):  
Pradhumna Lal Shrestha ◽  
Michael Hempel ◽  
Sushanta Rakshit ◽  
Hamid Sharif ◽  
John Punwani ◽  
...  

Traditional Wireless Sensor Network (WSN) solutions have been deemed insufficient to address the requirements of freight railroad companies to implement real-time monitoring and control of their trains, tracks and wayside equipment. With only ZigBee-based elements, the transmission capabilities of WSN devices are limited in terms of coverage range and throughput. This leads to severe delay and congestion in the network, particularly in railroad scenarios that usually require the nodes to be arranged in linear chain-like topology. In such a multi-hop topology to communicate from one end of a train to the locomotive — and due to ZigBee’s limited communication range — data needs to be transmitted using a very high number of hops and thus generates long delays and congestion problems. To overcome this drawback, we have proposed a heterogeneous multi-hop networking approach called “Hybrid Technology Networking” (HTN). In HTN we combined Wireless Local Area Network (WLAN) technologies like WiFi, which provide improved communication range and higher data rates, with low-power communication technologies like ZigBee. This significantly reduces the number of hops required to deliver data across the network and hence solves the issues of delay and congestion, while also achieving superior enery efficiency and network lifetime. The sensor nodes are logically divided into clusters and each cluster has a WiFi “gateway”. All intra-cluster communication is achieved via IEEE 802.15.4 and ZigBee protocols, while all inter-cluster communication utilizes WiFi protocol standards. To implement our proposed technology in railroad networks, we are designing hardware prototypes and simulation models to evaluate the functionality and performance of our HTN solution, which is designed around a dual network stack design governed by the HTN protocol. This ensures full compliance with IEEE and industry communication protocols for interoperability. Since no simulation tools that seamlessly combine both WSN and WLAN technologies in a single module exist, we wrote our own simulation environment using OPNET. In this paper, we have provided information of implementing the HTN protocol in OPNET and the simulation results for different scenarios relevant to railroad operations. These results will demonstrate the efficacy of our proposed system as well as provide the baseline data for testing the hardware devices in live networks. Under simulated traffic and channel conditions and device configurations, we observed a decrease of 77.27% in end-to-end delay and an increase of 69.70% in received data volume when using HTN compared to ZigBee-only multi-hop networks, simulated over 14 railcars in railroad-relevant scenarios.


2014 ◽  
Vol 721 ◽  
pp. 728-731
Author(s):  
Da Wei Dong ◽  
Xiao Guo Liu ◽  
Tian Jing

To reduce the number of inter-disturb access points and the interference among access points in same channel, with research on interference issus and channel assignment algorithms of wireless local area network, a scheme suitable for centralized wireless local area network was proposed aiming to minimize the total interference among access points, which comprehensively considerate the number of neighbor and the received power. And then the algorithm with cases was simulated and analyzed, the result of NS2 simulation indicated that the algorithm was simple, effective and feasible, which could realize dynamic adjustment to the wireless LAN RF channel and had a better load balance effect among non-overlapping channels.


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