Sathaporn Promwong

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.

Comprehensive characterization of a novel UWB elliptical planar monopole antenna

The rise of research in ultra wideband (UWB) antenna design must be followed by a proper method of antenna characterization. The emerging concept of UWB impulse radio (UWB-IR) compels the performance evaluation of UWB antenna should be assessed in different ways from narrowband antennas. In this paper, a comprehensive characterization of UWB antenna will be discussed. Based on the theory of antenna transfer function in frequency domain, some UWB transmission parameters in time domain are derived, i.e. waveform correlation, waveform width stretch ratio, and waveform relative gain. For practical testing, we propose a novel UWB elliptical planar monopole antenna as the characterized antenna. The results show that the overall performance and characteristic of the proposed antenna is very good, especially at the antenna boresight. The derived parameters can quantitatively characterize the UWB antenna for all the measured directions so that the detail of transmission performance of the UWB antenna could be known. Hopefully, the characterization scheme with the proposed antenna presented in this paper provide useful insight either for UWB antenna design or for evaluating UWB antenna performance.

Improvement of RFID based location fingerprint technique for indoor environment

In this paper, the improvement of an indoor localization using a fingerprint technique is proposed. The Radio Frequency Identification (RFID) system is utilized. In general, the RFID localization can be categorized into two main types: one is the reader localization in which the reader locations will be estimated and one is the tag localization in which the tag locations will be estimation. The selection of these two types depends on the applications. In this paper, the reader localization is considered because of the lower system cost. For the reader localization, although a large number of tags is used, the tag cost is much cheaper than the reader cost. The passive tags are employed as references attached to the ceiling at known locations and the reader carrying on the vehicle of interest is the target to be localized. The basic principle of the fingerprint technique is to find the location of the target by comparing its signal (or information) pattern with a previously recoded database of known signal (or information)-location data. Therefore, there are two main steps to estimate the target location: (i) construction of database containing the signals (or information) and their corresponding locations, and (ii) estimation of the target location. In this paper, firstly, the detected tags found by the reader at each location of interest are collected and from now on the detected tags are called a fingerprint. Secondly, the location of the reader can be estimated using three proposed methods using the intersection between the detected tags and fingerprints. The effectiveness of each method is verified by experiment data. The best result of location estimation error among three proposed methods is less than 35 cm.

Improvement of fingerprinting technique for UWB indoor localization

The indoor localization is highly desired for elevation in the industrial, public safety and medical technology. Its significant requirement is a high accuracy in dense multipath fading environments. This paper improves the main problem of indoor localization by using fingerprinting technique based on ultra wideband (UWB) channel measurement. In addition, the neural network algorithm is used to find the location that has 3 dimensions, x plane, y plane and z plane. The first path loss, the delay times of the first part, the average path loss and the average of delay time were applied to create the ultra wideband radio propagation parameters for fingerprinting technique. the results are shown in terms of histogram of distance errors between update and non-update the databases and countour graph of each of distance errors on the coordinates. According to the results, the fingerprinting technique with update database can identify the location more correctly than the fingerprinting technique with non-update database. It had accuracy at 1 meter as 88.57%. while the fingerprinting technique with non-update database was affected from the environment and the accuracy at 1 meter was lower than the fingerprinting technique with update database all the times of experiment.

Indoor measurement and modeling of RFID transmission loss at 5.8 GHz with human body

The radio frequency identification technology in frequency band at 5.8 GHz is becoming the important part of a high-speed data rate in the fields of narrow band application radio wave and in short range wireless communication system. According, the best performance of effects with human body in an indoor environment for the wireless body area networks are necessary to study. This paper, an experimental study and analyze of effects in the radio frequency identification performance of transmission signal with human body. Furthermore, we considers the characteristics of human body in each distances by using the vector network analyzer, and the microstrip antenna for both transmitter and receiver antennas. Therefore, this experiment will be benefit for researching and developing communications system of RFID propagation channel with wireless body area networks.

Measurement and Modeling of RFID Propagation Channel with in an Indoor Environment

The radio frequency identification (RFID) technology was automatic identify becomes was essential in the service an indoor environment such as contactless smart card and libraries at high frequency in free space transfer function in wireless communication usually consider used Frisss formula for analysis. This paper the RFID propagation channel at 2.45 GHz with indoor environment. The measurement result are evaluation by using Friiss transmission formula to find the magnitude and phase channel transfer function, path loss, and power delay profile. This technique is very useful for analyzed the signal strength and radio propagation loss of RFID transmission signal.

Indoor measurement results of UWB impulse radio for shot-range wireless systems with RMS delay spread and path loss

In this paper, we describe a simple method for measurement of the ultra-wideband (UWB) frequency response for evaluation of the path loss and RMS delay spread which are the important parameters for the wireless communications, probability and cumulative density of rms delay spread and path loss are evaluated based on the measurement of UWB indoor environment. For the measurement, the frequency responses of the UWB channel are acquired by using a vector network analyzer (VNA) over the frequency bandwidth of 3/spl sim/11 GHz. The biconical antennas are used for both the transmitter (Tx) and receiver (Rx) antennas. The probability density function and cumulative distribution function of the rms delay spread and path loss are shown. The results are discussed in this paper.

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.

Performance study of dynamic framed slotted ALOHA for RFID systems

When more than two tags respond to a reader request at same time slot, the tag collision occurs. This is one of disadvantages in radio frequency identification (RFID) system. The performance of anti-collision algorithms is important to overcome this problem. In this paper, the performance of dynamic framed slotted ALOHA (DFSA) is studied. The DFSA with mute tags is considered and compared with framed slotted ALOHA (FSA) with mute tags. The average used time slot, probabilities of ideal time slot, collision time slot and successful time slot are shown. The results are discussed in the conclusion.