Chamchoy, Monchai
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Item type:Publication, Empirically based path loss and penetration loss models for UWB communication in residential environment(2005-12-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A body-shadowing model for indoor UWB communication environments(2008-10-06); Radio channel characteristic is a very important factor for designing indoor UWB communication network. As we know, the indoor communication channel is limited by geometry of room and some obstruction in that room such as furniture, human operator, etc. These obstructions directly affect to quality of received signal, especially human who usually obstruct receiving signal. To efficient the network designing, the influence of human body shadowing on radio propagation in building UWB communication is investigated by involving propagation prediction model. This model will predict characteristics of the received signal affected from body shadowing by considering many wave propagation phenomenons such as reflection, refraction, absorption, etc. based on ray-tracing technique. The predicted results are shown in various forms such as power loss of received signal, mean excess delay and power delay profile. To verify the validation of the model, these results will be compared with the measured results. It is found that the measurement and prediction results are closely related. ©2008 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Characterization of in-home UWB channel with different antenna directivity(2004-12-01); ; - 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 QoS routing for pulse based UWB ad-hoc network(2006-12-01); Ultra wideband (UWB) is a prospective radio technology for wireless ad-hoc networks. In this paper we propose the Quality of Service (QoS) routing for pulse based UWB ad-hoc network. The performance of TH-UWB on the AWGN channel is studied. The PPM scheme with data rate of 110 Mbps is considered. As the simulation results, the information sent by single-hop transmission has error more than that sent by multihop communication. For the data transmission, TCP is useful for this system. The notion of QoS is a quarantee by network to the best satisfy. © 2006 IEEE. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The impact of path loss on cooperative MIMO transmission scheme for intelligent transport system(2006-12-01); Intelligence transport system (ITS) is the system which needs an effective cooperate between local base stations, vehicles and other communication networks in order to create an efficient communication and high-speed data transfer. The cooperative MIMO transmission scheme for ITS is proposed to solve the correlated fading channel. The impact of path losses in inter-vehicle communication and road to vehicle communication are investigated and discussed in the text. As the result, the path loss and correlated fading channel have become the cause of distorting the efficient communication. © 2006 IEEE. - 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, Rayleigh performance of transmitter preceding based-multiuser detection for DS-CDMA over Rayleigh fading environments(2004-09-27); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Characteristics of UWB propagation through building materials(2005-12-01); UWB system is the one type of several wireless communication that can be used in home networking, which have any probably obstruct by building material. Then the influences of the obstructions are considered. In this paper, the time dispersion and penetration loss are studied. The glass, gypsum, dry wood and partition board are considered the obstruction materials. The channels with these materials are measured in a fully anechoic chamber by using the vector network analyzer. The measurement frequency range is set to be 3-11 GHz, which covered the full band of UWB specified by FCC. The biconical antennas are used for both transmitter and receiver. The time dispersion and penetration loss for each material are evaluated based on the measurement channels. The data of theses results is useful for considering the UWB link budget.