scholarly journals Study on the Signal Transmission Characteristics of 2.4GHz Wireless Network in Dorms

2016 ◽  
Vol 12 (10) ◽  
pp. 58 ◽  
Author(s):  
Guoqiang Hu
Keyword(s):  
Radio Frequency ◽  
Wireless Network ◽  
Signal Transmission ◽  
Signal Strength ◽  
Received Signal Strength ◽  
Relational Model ◽  
Transmission Characteristics ◽  
Cubic Polynomial ◽  
Communication Distance

<p><span style="font-size: small;"><span style="font-family: Times New Roman;">In accordance with the deployment requirements of WLAN node in college student dorms and its features of application environment, this paper studies the relevance among factors like radio-frequency signal transmission characteristics, communication distance, AP height and transmission path, etc., with a case study of AP radio frequency 2.4GHz. Experiments show that the attenuation of wireless network signal in student dorms conforms to Keenan-Motley model. When AP is fixed, the signal strength received by laptop generally reduces with the increase of communication distance, yet just opposite with packet loss rate. When deploying AP, 1.25-1.75 height is ideal, and one-side coverage of 3 dorm rooms optimal. Based on the above researches, a relational model of AP height, communication distance and received signal strength is established. In it, model parameter  and AP height display a cubic polynomial relationship, and attenuation coefficient  and AP height show a quadratic polynomial relationship. Experiment results demonstrate that this model can satisfactorily predict the received signal strength of different AP heights and communication distances, providing technical support for wireless network deployment in student dorms. </span></span></p>

scholarly journals COMPARISON OF WIRELESS ADAPTERS INTERFERENCE BASED ON DIFFERENCES OF FLOOR POSITION

2021 ◽  
Vol 83 (4) ◽  
pp. 151-157
Author(s):  
Sasa Ani Arnomo ◽  
Yulia Yulia ◽  
Noraini Ibrahim
Keyword(s):  
Wireless Network ◽  
Signal Strength ◽  
Access Point ◽  
Received Signal Strength ◽  
Weak Signal ◽  
Received Signal Strength Indicator ◽  
Average Value ◽  
Internet Users ◽  
Wireless Signal

The wireless network adapter has now been widely developed. The wireless adapter receives signal strength has several levels. It depends on the signal strength of the device with respect to the wireless signal and access point. The external adapter is used by computers that are not equipped with a wireless network adapter. Usually, internet users use a USB wireless adapter. An external adapter can also amplify signal reception from hotspots. The problem is how users consider using an external wireless adapter or just an onboard wireless adapter when there are many networks interfering with the weak signal strength of the access point. The method is implemented by measuring the value of the Received Signal Strength Indicator (RSSI). The purpose of this study is to compare the received signal strength in conditions where the signal before interference and after experiencing interference (interference). Meanwhile, the measured RSSI value is divided into four floors and with different distances for each floor. Each floor is measured by five distances. The average value of signal strength at a distance of 10 meters is -74 dBm using the onboard wireless adapter and -69 dBm using a USB wireless adapter. The value obtained after the interference is -75 dBm and the USB wireless adapter gets -61 dBm. The reduction of the RSSI value between interference and non-interference is 3%. The onboard wireless adapter is affected by interference while the external wireless adapter is not affected. 

scholarly journals Design and Implementation of Directional Sensors for Privacy-Ensured Device-Free Target Localization in Indoor Environment

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Ata ur Rehman ◽  
Zeeshan Ellahi ◽  
Asif Iqbal ◽  
Farman Ullah ◽  
Ahmed Ali ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Indoor Environment ◽  
Signal Strength ◽  
Received Signal Strength ◽  
Target Localization ◽  
Ism Band ◽  
Design And Implementation ◽  
Directional Sensors ◽  
Device Free ◽  
Improved Accuracy

This paper presents two radio frequency (RF) sensors with different directivities designed and tested for device-free localization (DFL) in an indoor environment. Mostly, in smart homes and smart offices, peoples may be irritated by wearing the device on them all the time. As compared with device-based localization, the proposed sensors can localize both cooperative and non-cooperative targets (intruders and guests etc.) without privacy leakages. Both sensors are tested to detect the change in received signal strength (ΔRSS) due to the presence of an obstacle. RF sensors, i.e., antennas are designed to operate in the ISM band of 2.4–2.5 GHz. Experimental results show that the sensor with higher directivity provides better ΔRSS that helps in improved accuracy to detect a device-free target.

scholarly journals Modelling and Analysis of Emitter Geolocation using Satellite Tool Kit

2020 ◽  
Vol 70 (4) ◽  
pp. 440-447
Author(s):  
Suman Agrawal ◽  
Anupam Sharma ◽  
Charul Bhatnagar ◽  
D.S. Chauhan
Keyword(s):  
Radio Frequency ◽  
Multiple Antennas ◽  
Signal Strength ◽  
Received Signal Strength ◽  
Geostationary Satellite ◽  
Space Environment ◽  
The Earth ◽  
The Difference ◽  
Geolocation Accuracy

This paper considers geolocation of a stationary radio frequency emitter which is being steered by multiple antennas installed on a geostationary satellite using received signal strength metric. The difference in the signal strengths is measured by the antennas and subsequently plotted as lines of position on the surface of the earth. Intersection of these two or more lines of position indicates the location of the terrestrial radio frequency transmitters. This problem is appropriately modelled using a satellite tool kit that simulates the space environment involving satellites, antennas, emitters, etc in a realistic and integrated manner. Accuracy and size of the geolocation area depend on the distance between emitters and the receiver and also on the contour widths geometry. Results of geolocation accuracy are compared by installing the radio frequency emitter at increasing latitudes and at varying contour widths. It is observed that the emitters placed at lower latitudes and having smaller contour widths provided higher accuracy in geolocation that validates the proposed formulation.

scholarly journals Inertial measurement unit–aided dual-frequency radio frequency identification localization in line-of-sight and non-line-of-sight hybrid environment

2018 ◽  
Vol 14 (3) ◽  
pp. 155014771876203
Author(s):  
Jie Wu ◽  
Minghua Zhu ◽  
Bo Xiao ◽  
Wei He
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Identification ◽  
Inertial Measurement Unit ◽  
Signal Strength ◽  
Received Signal Strength ◽  
Measurement Unit ◽  
Line Of Sight ◽  
Inertial Measurement ◽  
Frequency Identification ◽  
Non Line Of Sight

The mitigation of non-line-of-sight propagation conditions is one of main challenges in wireless signal–based indoor localization. When radio frequency identification localization technology is applied in applications, the received signal strength fluctuates frequently due to the shade and multipath effect of radio frequency signal, which could result in localization inaccuracy. In particular, when tag carriers are walking in line-of-sight and non-line-of-sight hybrid environment, great attenuation of received signal strength will happen, which would result in great positioning deviation. The article puts forward a dual-frequency radio frequency identification–based indoor localization approach in line-of-sight–non-line-of-sight hybrid environment with the help of inertial measurement unit. Dual-frequency radio frequency identification includes passive radio frequency identification and active radio frequency identification. Passive radio frequency identification is used to assist in determining the tag initial location with passive reader. Active radio frequency identification is used to locate the tag and send the sensor information to active radio frequency identification readers. The proposed method includes three improvements over previous received signal strength–based positioning methods: inertial measurement unit–aided received signal strength filtering, inertial measurement unit–aided line-of-sight/non-line-of-sight distinguishing, and inertial measurement unit–aided line-of-sight/non-line-of-sight environment switching. Also, Cramér–Rao low bound is calculated to prove theoretically that indoor positioning accuracy for the proposed method in line-of-sight and non-line-of-sight mixed environment is higher than position precision using only received signal strength information. Experiments are conducted to show that the proposed method can reduce the mean positioning error to around 3 m without site survey.

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