Monchai Chamchoy

Spatial correlation properties of multiantenna UWB systems for in-home scenarios

Ultra-wideband (UWB) communication has recently attracted great interest for short-range and high data rate wireless networks. Multi-antenna UWB transmissions, on the other hand, are considered as an effective technique to improve the link reliability and transmission rate. The benefit of such systems can be drawn from the correlation independently. In this paper, the spatial correlation properties of the transmitter/receiver for the multiantenna UWB systems under line-of-sight (LOS) and non-line-of-sight (NLOS) conditions are presented. The synthesized antenna arrays are used to represent the multiple antennas at both ends. The correlation results show that the correlation decreases as the antenna separation distance increases for the LOS scenario. In the case of the NLOS environment, the correlation does not depend on such separation distance.

Empirically Based Path Loss and Penetration Loss Models for UWB Communication in Residential Environment

This paper contains measured data and empirical models for 3.1~10.6-GHz radio propagation path loss and aggregate penetration loss (APL) in residential areas for UWB applications. A frequency domain based experiment is performed for line-of-sight (LOS) and obstruction propagation conditions. The double ridge horn antenna and the biconical antenna are used to investigate the dependence of the antenna directivity on the UWB path loss. While the penetration loss is modeled under the directional propagation scheme. The characterization of the path loss exponent, n, and the APL are investigated. Therefore, the propagation prediction models are developed to understand the phenomenon of the futuristic indoor residential communication systems for home wireless networking

Study on propagation path loss and BER performance for fixed broadband WiMax

Ground reflection (two-ray) model is one of the propagation that can be employed with various systems for wireless communication. Consequently, the WiMax system above ground reflection model is proposed in this paper to evaluate the path gain, received power and the performance of the system. Two twenty-five meter-high transmit antennas and two one point two meter-high receive antennas are used in this simulations. Moreover, a space time block code (STBC) in OFDM (Orthogonal frequency division multiplexing) is used as well. In this paper, the path gain and the received power are proposed for ground reflection model that depend on various parameters. For different frequency, the path gain of low frequency is higher than high frequency.The path gain of ground is different from dry concrete before Rb distance. The performance of the added gain of transmit antennas is very significant for the system for the limited distance that depend on the system.

Characteristics of UWB propagation through building materials

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 these results is useful for considering the UWB link budget.

Experimental evaluation scheme of UWB propagation channel with human body

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.

A body-shadowing model for indoor UWB communication environments

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.

Study on Qos Routing for Pulse Based UWB Ad-Hoc Network

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 multi-hop communication. For the data transmission, TCP is useful for this system. The notion of QoS is a guarantee by network to the best satisfy

The Impact of Path Loss on Cooperative MIMO Transmission Scheme for Intelligent Transport System

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

Evaluation of DVB-T2 transmission channel in Bangkok, Thailand

This paper describes the evaluation of DVB-T2 transmission channel in Bangkok Thailand. The DVB-T2 test signal is transmitted in Bangkok Thailand. Type of transmission channel were used including Gaussian, Rician for fix rooftop reception. The measurements are consisting of a several environments such as open area, urban area, high building area. The measurement result are include Power Output from transmitter after combiner, LBER, bBER, NsMAR (Noise Margin), MER (Modulation Error Ratio), SNR (Signal to Noise Ratio), CNR (Carrier to Noise Ratio), and Signal. The measurement result of this paper lead to the evaluation of DVB-T2 transmission channel for environment of Bangkok, Thailand and could be useful to improve and to design the digital television broadcasting network in Thailand especially in urban area like Bangkok.

Characteristics of UWB Radio Propagation With Building Materials

UWB technology is intended to be used in wireless personal area networks and home networking, which has any probably obstruct by building material. Then, the influences of the obstructions on UWB pulse are considered. In this paper, the power delay profile, the time dispersion and penetration loss are considered. The channels with these materials are measured using the vector network analyzer. The measurement frequency range is set to 3~11 GHz, which covered the full band of UWB specified by FCC. The biconical antennas are used for both transmitter and receiver. The power delay profile, the time dispersion and penetration loss for each material are evaluated based on the measurement channels. The experiment results are needed for considering the UWB link budget