In this paper, we present a low-complexity joint estimation algorithm of the direction of arrival (DOA) and time of arrival (TOA) for mobile location system, which is based on a multiple signal classification (MUSIC) algorithm. To reduce the computational overhead of conventional joint DOA/TOA estimation algorithms, the proposed approach em- ploys two complexity reduction schemes: separation of the signal vector for individually extracting DOA/TOA and pseudo- spectrum computation with discrete Fourier transform (DFT). In addition, the loss of accuracy caused by the separation process is compensated by summing multiple pseudo-spectrums. Compared with the conventional two-dimensional (2-D) MUSIC algorithm, the proposed low-complexity algorithm not only substantially reduces the computational complexity but also provides better performance, especially in a low signal-to-noise ratio (SNR). The effectiveness of the proposed algorithm is verified by simulation results.
[Show abstract][Hide abstract] ABSTRACT: ABSTRACT: In these days, the development of positioning technology for realizing ubiquitous environments has become one of the most important issues. The Global Positioning System (GPS) is a well-known positioning scheme, but it is not suitable for positioning in in-door/building environments because it is difficult to maintain line-of-sight condition between satellites and a GPS receiver. To such problem, various positioning methods such as RFID, WLAN, ZigBee, and Bluetooth have been developed for indoor positioning scheme. However, the majority of positioning schemes are focused on the two-dimension positioning even though three-dimension (3D) positioning information is more useful especially in indoor applications, such as smart space, U-health service, context aware service, etc. In this paper, a 3D positioning system based on mutually orthogonal nano-scale impulse radio ultra-wideband (IR-UWB) signals and cross array antenna is proposed. The proposed scheme uses nano-scale IR-UWB signals providing fine time resolution and high-resolution multiple signal specification algorithm for the time-of-arrival and the angle-of-arrival estimation. The performance is evaluated over various IEEE 802.15.4a channel models, and simulation results show the effectiveness of proposed scheme.
Nanoscale Research Letters 10/2011; 6(1):544. DOI:10.1186/1556-276X-6-544 · 2.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this paper, a new positioning scheme with impulse postfix OFDM (IP-OFDM) systems is proposed for estimating the positional information of a user within a wireless local area network. In the proposed scheme, the channel information is estimated by the IP of the IP-OFDM symbol in the time domain, and then the round-trip time and the angle of signal arrival from a wireless terminal to an access point equipped with a uniform linear antenna array are investigated for time-of-arrival (TOA) and angle-of-arrival (AOA) estimation for a user. The position of the wireless terminal is finally estimated by combining the estimated TOA and AOA information. The performance of the proposed scheme is evaluated with computer simulations, and the error characteristics are analyzed with respect to the TOA error, and the AOA error influence on the positioning error. According to the simulation results, the positioning error of the proposed scheme can be reduced to some centimeters for high signal-to-noise ratio (SNR). The major influence on the positioning error comes from the TOA error in low SNR, while the AOA error has more influence on the positioning error in high SNR.
Wireless Personal Communications 03/2014; 75(1):261-271. DOI:10.1007/s11277-013-1361-z · 0.65 Impact Factor
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