Chamchoy, Monchai
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Item type:Publication, Accuracy Analysis of Indoor Positioning Using Min-Max Method(2025-01-01); ; In this paper, the accuracy analysis of indoor positioning using min-max method is proposed. The distance error model is applied to estimate the distance between the transmitter and user's position with different path loss exponent and fading amount of indoor channel. The total $\mathbf{1 0 0}$ coordinates of user's positions are estimated using min-max method. The distance error at each position, probability density function (PDF) and cumulative distribution function (CDF) of distance errors are illustrated. The mean of analysis distance error corresponds with the mean of measurement distance error with same path loss exponent and fading amount of indoor channel. The results show that it is possible to use this accuracy analysis to estimate the distance error in an indoor environment. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Optimum Weight Parameter of Weight Centroid Method for Indoor Positioning in Environment with Different Path Loss Exponent and Multipath Fading Effect(2024-04-01); This paper proposes optimum weight parameter of weight centroid method for indoor positioning in environment with different path loss exponent and multipath fading effect. The indoor environment is defined as square with each side 10 m long. There is a transmitter installed in the center of each side. The distance error model is applied to calculate the distances between the location coordinates of user and the location coordinates of transmitters in environment with different path loss exponent and multipath fading. The total 100 location coordinates of user are estimated by using weight centroid method, varying weight parameter in the range of 1 to 10. The optimum weight parameter is defined as the case where mean of distance error of all positions is the least. The optimum weight parameter for environment with different path loss exponent and multipath fading effect is illustrated. The results show that the optimum weight parameter changes slightly with the path loss exponent and tends to change with the standard deviation of the multipath fading effect divided into 3 periods. The first period tends to increase slowly, the second period tends to increase rapidly, and the third period tends to fluctuate up and down. Moreover, the size of the indoor environment has very little impact on the optimum weight parameter. These results make it possible to select optimum weight parameter for case with path loss exponent and standard deviation of multipath fading effect that match or are close to the channel of indoor environment. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Accuracy Study of Indoor Positioning with Bluetooth Low Energy Beacons(2020-03-01); Currently, Bluetooth low energy (BLE) beacons are widely used for positioning, especially an indoor environment. However, there is still high error due to dense multipath fading that often occurs in the indoor environment. This paper presents the accuracy study of indoor positioning with BLE beacons. The indoor environment is the room of 91.8 m<sup>2</sup> with 3 BLE beacons. The user equipment (UE), iPhone XS Max, with Beacon Analyzer application is used to measure the received signal strength (RSS) of each BLE beacon. Fingerprinting technique with least root mean square (RMS) error matching is used to estimate the position of UE. The accuracy that obtained from single measurement and average five measurements is studied. The RSS fingerprint of each BLE beacon is shown. The cumulative distribution function (CDF) of distance error is evaluated and illustrated. From the results, the average five measurements can reduce the average distance error about 0.86 m. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Experimental evaluation scheme of UWB radio propagation channel with human body(2005-12-01); ; This paper presents the evaluation scheme to investigate the pulse distortion, propagation loss due to human body shadowing. The matched filter is employed at the UWB receiver to maximize the SNR. The propagation loss and matched filter gain of the passband rectangular pulse are simulated for comparing with the experiment results. The experimental channels are taken for several T-R separation distances in an indoor environment. The frequency responses of the radio channels are acquired by using a vector network analyzer (VNA) over the frequency bandwidth of 3 GHz to 11 GHz. From the results, the distortion and the propagation loss of the UWB pulse increase as the T-R separation distance increases, especially when the fully shadowing is occurred. © 2005 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study on RSRP of LTE Mobile Phone on Thailand's National Highway(2018-07-02); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study on Accuracy of Min-Max Method Using Distance Error Model for Indoor Positioning(2022-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Investigation of ultra-wideband pulse distortion due to the body shadowing(2005-12-01); ; In this paper, the distortion of ultra-wideband (UWB) pulse due to the human body shadowing is investigated. The frequency responses of the radio channels are acquired by using a vector network analyzer (VNA) over the frequency bandwidth of 3 GHz to 11 GHz. The experimental channels are taken for several T-R separation distances in the indoor environment. Consequently, the characteristics of the UWB pulse distortion including the effect of transmitter/receiver antennas and human body are examined. The pulse distortion is considered by using the percentage of the correlation coefficient between the transmitted signal and the received signal. As the results, the distortion of UWB pulse increases as the T-R separation distance increases, especially when the fully shadowing is observed. © 2005 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Ground reflection model in rough surface forUWB impulse radio(2005-12-01); ; ; Keawmechai, SompophUltra-wideband (UWB) is currently wide interesting technology of wireless communication technology in building and home entertainment. In order to be the most effective wireless communications, we have to consider the parameters which are vital signal transmission factors of UWB. As a consequent, imitation of UWB signal transmission in two-part model so as to notice reflected signal from several rough types of ground such as Brick and Limestone is demonstrated in this abstracts. Friis' transmission formula and Rayleigh equation are used to calculate in this model for searching any effects happened by reflection of rough ground and analyzed in path loss, path gain and time dispersion as RMS delay spread. © 2005 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study on accuracy of trilateration method for indoor positioning with BLE beacons(2020-07-01); Nowadays, indoor positioning services of mobile phone with Bluetooth low energy (BLE) beacons are increasingly used. However, due to the indoor environment has dense multipath fading, the positioning system has low accuracy. In this paper, the accuracy study of trilateration method for indoor positioning with BLE beacons is presented. The indoor environment room with 9.0 m width, 10.2 m length and 3 BLE beacons is studied. The received signal strength (RSS) of each BLE beacon is measured by using mobile phone. The distance between each BLE beacon and mobile phone is evaluated using channel model. After that, the trilateration method is used to approximate the position of mobile phone. The accuracies, which are obtained from one, average five and average ten measurements, are studied. The distance errors of all positions and the cumulative distribution function (CDF) of the distance error are calculated and shown. The results show that the average multiple measurements tend to decrease the distance error.