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Equatorial spread-F forecasting model with local factors using the long short-term memory network
(2023-12-01)
Thammavongsy, Phimmasone
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Supnithi, Pornchai
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Myint, Lin Min Min
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Hozumi, Kornyanat
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Lakanchanh, Donekeo
The predictability of the nighttime equatorial spread-F (ESF) occurrences is essential to the ionospheric disturbance warning system. In this work, we propose ESF forecasting models using two deep learning techniques: artificial neural network (ANN) and long short-term memory (LSTM). The ANN and LSTM models are trained with the ionogram data from equinoctial months in 2008 to 2018 at Chumphon station (CPN), Thailand near the magnetic equator, where the ESF onset typically occurs, and they are tested with the ionogram data from 2019. These models are trained especially with new local input parameters such as vertical drift velocity of the F-layer height (Vd) and atmospheric gravity waves (AGW) collected at CPN station together with global parameters of solar and geomagnetic activity. We analyze the ESF forecasting models in terms of monthly probability, daily probability and occurrence, and diurnal predictions. The proposed LSTM model can achieve the 85.4% accuracy when the local parameters: Vd and AGW are utilized. The LSTM model outperforms the ANN, particularly in February, March, April, and October. The results show that the AGW parameter plays a significant role in improvements of the LSTM model during post-midnight. When compared to the IRI-2016 model, the proposed LSTM model can provide lower discrepancies from observational data. Graphical Abstract: [Figure not available: see fulltext.].
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Measurement and Modeling of WUWB Impluse Radio Transmission with Indoor Environment
(2018-07-02)
Praseuth, Souphavady
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Lakanchanh, Donekeo
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Luangxaysana, Khanthanou
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Promwong, Sathaporn
Wireless ultra wideband (WUWB) technology is developed very fast in the past few years. It offers many competitive advantages. In communications, it can provide better performance for wireless network applications with high data rate and multimedia system. WUWB thus, communication systems have been subjected to extensive research and development projects. This paper focuses on the power delay profile in WUWB-IR system. This analysis emphasizes on power delay profile consideration between transmitter and receiver based on measurement data in an indoor environment. This research considers in an indoor environment for short range communication. The concept of model, we suppose the transmitter is a human body and receiver is general electric appliance for example television, camcorder, Laptop, Mobile phone and other appliances that can received signal from the human body.
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WLAN Localization Measurement and Analysis Using RSS and TOA Positioning Methods
(2018-07-02)
Lorvannger, Khounhack
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Lakanchanh, Donekeo
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Tiengthong, Thanadol
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Promwong, Sathaporn
Wireless local area network (WLAN) has been exclusively research due to its widely used applications. Its operate frequency spectrum is in the ISM band and regulated in IEEE 802.11 family. Localization is one of the application which able to used WLAN signal. Its can be used in various applications such as logistics, security, disaster rescue operation tracking, and military service. Since the various kind of its applications is work in indoor environment, the indoor localization requires high accuracy. The receive signal strength (RSS) and time of arrival (TOA) are a parameter that used in the comparison between min-max technique and trilateration technique in this paper. In the measurement of this research, the frequency bandwidth is ranging from 2.3 GHz to 2.5 GHz, an access point is used to represent both of transmit antenna and receive antenna. The cumulative distribution function (CDF) is used for study the most accuracy.
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Adaptive OFDM modulation techniques over fading channel for wireless communication systems with an 80 MHz bandwidth
(2010-05-05)
Lakanchanh, Donekeo
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Noppanakeepong, Suthichai
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Yoshizawa, Shingo
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Miyanaga, Yoshikazu
The orthogonal frequency division multiplexing (OFDM) is one of the promising technologies to improve the spectral efficiency, enhance system capacity and mitigate inter-symbol interference in the wireless communication system. In this paper, we aim at the study on adaptive modulation and coding technologies for wireless system over frequency selective fading channel. This adaptive allocation algorithm assigns the sub-carriers. We are applied adaptive modulation technique to each sub-carrier to keep required BER and PER performance. The system chooses modulation among BPSK, QPSK, 16QAM and 64QAM which the estimated SNR of the sub-carrier inhabits. Adaptive modulation can improve communication performance under small SNR. The computer simulation result shows the BER, PER and Throughput performance can be improved under 30 dB of SNR region. ©2010 IEEE.
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Histogram compensation to improve blind modulation detection in adaptive OFDM
(2009-12-01)
Lakanchanh, Donekeo
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Yoshizawa, Shingo
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Noppanakeepong, Suthichai
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Miyanaga, Yoshikazu
This paper proposes a blind modulation detection technique for adaptive orthogonal frequency division multiplexing (Adaptive OFDM) communications. Adaptive modulations are applied to improve communication performance in OFDM over complicated multi-path fading channels. This paper proposes a new method which reduces detection errors in blind modulation and improves communication throughput in adaptive OFDM systems. The new proposed is based on statistical methods using a combination of distance histogram and phase histogram methods. It can improve communication performance and increases a data rate by not sending side information about modulation modes. The proposed method has showed better blind detection performance at lower SNR regions than the previous method. ©2009 IEEE.
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Rainfall rate and rain attenuation model in Bangkok, Thailand
(2008-12-01)
Chankeaw, Natthapong
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Udomariyasap, Pongputhai
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Lakanchanh, Donekeo
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Noppanakeepong, Suthichai
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Leelaruji, Nipha
This paper describes the measurement of rainfall rate at King Mongkut's Institute of Technology Ladkrabang (KMITL), Bangkok, Thailand, by using satellite signal from Thaicom5. Three years measurement of rainfall rate are presented. The experimental results indicate that the measured rainfall rate are 90mm/hr in 2005, 94 mm/hr in 2006 and 102 mm/hr in 2007. Moreover, we have developed new modify prediction model of rain attenuation by ITU-R rain attenuation model. The model provides for prediction of annual and for expected year to year variations. This model applied to collecte data compared with ITU-R model. From the results of prediction model at KMITL, we found that the highest rainfall rate 102 mm/hr in 2007 cause to signal attenuate 14.34 dB. © 2008 IEEE.
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Rainfall rate and rain attenuation in Ku-Band satellite signal in Thailand and Laos
(2006-12-01)
Lakanchanh, Donekeo
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Datsong, Attasit
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Leelaruji, Nipha
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Hemmakorn, Narong
This paper describes the experiment of rainfall rate and rain attenuation. One year measurement of rainfall rate and rain attenuation of satellite signal on Ku Band, downlink of Thaicom 3 at King Mongkut's Institute of Technology Ladkrabang (KMITL) in Bangkok using 0.5 meter antenna with horizontal polarized and measurement of rainfall rate at National University of Laos (NUOL) in Vientiane and at Paksong in the southern of Laos are investigated, The relation of rainfall rate and rain attenuation on three ground stations are presented. Correlation between rainfall rate and cumulative time are described in monthly and yearly include the comparison of yearly cumulative rainfall rate between measurement and ITU-R model are presented. © 2006 ICASE.
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Propagation effect by rain in Ku and Ka band satellite communication system
(2006-12-01)
Lakanchanh, Donekeo
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Udomareyasap, Pongputhai
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Leelaruji, Nipha
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Hemmakorn, Narong
This paper present the contribute of rainfall rate and rain attenuation in Ku band measurement and prediction rain attenuation in Ka band by using ITU-R model at King Mongkut's Institute of Technology Ladkrabang (KMITL), Bangkok, Thailand. One year measurement of rainfall rate and rain attenuation of Ku band satellite signal of 59 degree elevation angle is presented. The experimental results, we found that on the rainfall rate R<inf>0.01</inf> is 90 mm/hr, the measured Ku band rain attenuation A<inf>0.01</inf> is about 11 dB while predicted Ka band rain attenuation is 20 dB, The effect of rain attenuation characteristics of Ka band and Ku band satellite signals are compared. © 2006 IEEE.

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