Automatic Test Bench for Selected Transmission Parameters of Power Line Conductors

This paper presents automatic test bench used for measurement of selected high frequency parameters of a power copper line. The aim is fast estimation of line behavior in context of Power Line Communication (PLC). The hardware interface uses sinusoidal waveform generator, digital oscilloscope and a PC-class computer. The software interface created in LabView environment performs signal processing and data presentation

Statistical analysis of indoor RSSI read-outs for 433 MHz, 868 MHz, 2.4 GHz and 5 GHz ISM bands

This paper presents statistical analysis of RSSI read-outs recorded in indoor environment. Many papers concerning indoor location, based on RSSI measurement, assume its normal probability density function (PDF). This is partially excused by relation to PDF of radio-receiver's noise and/or together with influence of AWGN (average white Gaussian noise) radio-channel – generally modelled by normal PDF. Unfortunately, commercial (usually unknown) methods of RSSI calculations, typically as "side-effect" function of receiver's AGC (automatic gain control), results in PDF being far different from Gaussian PDF. This paper presents results of RSSI measurements in selected ISM bands: 433/868 MHz and 2.4/5 GHz. The measurements have been recorded using low-cost integrated RF modules (at 433/868 MHz and 2.4 GHz) and 802.11 WLAN access points (at 2.4/5 GHz). Then estimated PDF of collected data is shown and compared to normal (Gaussian) PDF

Comparison of indoor/outdoor, RSSI-based positioning using 433, 868 or 2400 MHz ISM bands

This paper compares accuracy of indoor positioning systems using one of three selected ISM bands: 433, 868 or 2400 MHz. Positioning is based on Received Signal Strength Indication (RSSI), received by majority of ISM RF modules, including low-cost ones. Investigated environment is single, indoor space (e.g. office, hall) and personal use, thus 2-dimensional (2D) coordinate system is used. Obtained results, i.a. average positioning error, are compared with similar measurements taken at outdoor, open space environment. The system is local, i.e. its operational area is limited by range of used RF modules – typical a few tens of meters. The main focus is research of how much accuracy (and usefulness) can be expected from standard RF modules working at typical ISM frequencies

Analysis of Object Location Accuracy for iBeacon Technology based on the RSSI Path Loss Model and Fingerprint Map

This paper presents analysis of object location accuracy of a mobile device on the basis of the iBeacon technology. The research starts with radio signal strength indicator analysis along the corridor in order to create a path loss model for iBeacon. Two cases are taken into account: line of sight and non-line of sight for model creation. For both cases two tests: Chi-square, Shapiro-Wilk have been performed. It has also been checked if the HCI (Host Controller Interface) is a source with a memory. Acquired data have been filtered with different type of filters, e.g. median, moving average and then compared. Next, the authors evaluated the indoor positioning trilateration algorithms with the use of created model for exemplary hall. The RSSI map (radiomap) was created and the logarithm propagation model was designed. The logarithmic model estimated distance with average error 1.09m for 1 – 9m and 1.75m for 1-20m and after trilateration, the positions with average error 2.45m was achieved. A statistical analysis for acquiring data led to the final conclusion which enhanced knowledge about positioning based on the popular iBeacon technology

Comparison of 2.4 and 5 GHz WLAN network for purpose of indoor and outdoor location

This paper presents comparison of prototype location system built with standard components of 2.4 and 5 GHz WLAN network infrastructure. The system can be used for personal or other objects’ positioning, both for indoor and outdoor environments. The system is local, i.e. its operational area is limited to WLAN network operating range. The system is based on standard and widely available WLAN components (access points, network adapters). The goal is to avoid any hardware and software modifications. Also position calculation should not be power hungry operation. Method of location is based in Received Signal Strength Indication (RSSI) returned by most of RF ICs (including WLAN). The main focus is research of how much accuracy (and usefulness) can be expected from standard WLAN hardware. Both static and dynamic scenarios have been tested and compared