• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.139-147
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• 2003

In this paper we proposed system parameter values of M-ary PPM/TH(Pulse Position Modulation/Time Hopping) ultra-wideband systems having data rate of 100 Mbps for the frequency band, which is allocated by Federal Communications Commission(FCC). We also analyzed performance of the proposed system in the AWGN channels. According to the results of performance analysis, It is observed that available pulse duration is very limitative for this system. In case of constant data rate, if M and the pulse repetition numbers are increased, then the system performance is improved and the user number is decreased.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.221-224
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• 2005

In this paper, We have designed, fabricated and measured a stacked planar antenna for Ultra-Wideband communication. Radiation parts of the antenna have exponential curve and fed by strip feeding network. We have used the HFSS of Ansoft to simulate the antenna. It was designed to work on a substrate Teflon of thickness 1.575mm and relative permittivity 3.2. The proposed antenna covered the entire UWB band( 3.1GHz $\sim$ 10.6GHz ) for S11$\leq$l0dB. Also the proposed antenna show a good characteristics, linear phase, omni -directional pattern lot UWB applications. Besides the measured results have a reasonable agreement with the simulated results.

• ETRI Journal
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• v.36 no.2
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• pp.309-312
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• 2014

A novel compact pattern diversity slot antenna for ultra-wideband (UWB) and Bluetooth applications is presented. This antenna consists of two modified coplanar waveguides that feed staircase-shaped radiating elements, wherein two different fork-like stubs are placed at the $45{\circ}$ axis. The measured results show that this proposed antenna operates from 2.3 GHz to 12.5 GHz, covering Bluetooth, WLAN, WiMAX, and UWB. The performance of radiation patterns and the corresponding envelope correlation coefficient prove this antenna is suitable for MIMO/diversity systems. Also, the antenna's compact size makes it a good candidate for portable devices.

• ETRI Journal
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• v.36 no.3
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• pp.460-468
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• 2014

This paper addresses the problem of joint time of arrival (TOA) and direction of arrival (DOA) estimation in impulse radio ultra-wideband systems with a two-antenna receiver and links the joint estimation of TOA and DOA to the sparse representation framework. Exploiting this link, an orthogonal matching pursuit algorithm is used for TOA estimation in the two antennas, and then the DOA parameters are estimated via the difference in the TOAs between the two antennas. The proposed algorithm can work well with a single measurement vector and can pair TOA and DOA parameters. Furthermore, it has better parameter-estimation performance than traditional propagator methods, such as, estimation of signal parameters via rotational invariance techniques algorithms matrix pencil algorithms, and other new joint-estimation schemes, with one single snapshot. The simulation results verify the usefulness of the proposed algorithm.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.1
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• pp.33-37
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• 2009

In this paper, a printed small Ultra-Wideband (UWB) antenna with directive radiation characteristics based on combination of electric-magnetic radiators is presented. The combinations of the electric and magnetic type antennas result in the directive radiation patterns for all observed UWB frequency band. Simple combination of dipole antenna and loop antenna is also presented to show that proper configuration of electric radiator and magnetic radiator can produces directive radiation characteristics. The target frequency is from 3.1 GHz to 10.6 GHz with size of $15\;mm{\times}31\;mm$. A proto-type of the combined antenna is simulated, fabricated and measured. Simulation and experimental results of input impedance and gain characteristics of the proposed antenna are presented. There are good agreements between the simulated and measured VSWR curves. Also, the results show the directive radiation characteristics with small antenna form factor over the target frequency range.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.47-52
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• 2010

The low power of ultra-wideband (UWB) signal makes the acquisition of UWB signal be a more challenging task. In this paper, we propose the method of high order template signal technique that reduces the synchronization time. Experimental results are presented to show the improvements of performance in the mean acquisition time (MAT) and the probability of detection. The performance compared with the serial search, the truly random search and the random permutation search. It is shown that over typical UWB multipath channels, a random permutation search scheme may yield lower MAT than serial search.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3557-3571
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• 2014

We develop a secret key generation scheme using phase estimation in ultra-wideband (UWB) wireless fading channels. Based on the reciprocity theorem, two terminals extract the phase of the channel as a common random source to generate secret bits. Moreover, we study the secret key rate by a pair of nodes observing correlated sources and communicating to achieve secret key agreement over public communication channels. As our main results, we establish a more practical upper bound from Cramer-Rao bound (CRB) and compare it with a universally theoretical upper bound on the shared maximum key rate from mutual information of correlated random sources. Derivation and numerical examples are presented to demonstrate the bound. Simulation studies are also provided to validate feasibility and efficiency of the proposed scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.1-7
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• 2006

Based on the new detection criterion proposed in Part 1 for the detecton of weak M-ary signals, a detection scheme for ultra wideband multiple access systems is investigated in the presence of impulsive interference. Simulation results show that the proposed detector, requiring less complexity, possesses almost the same performance as the maximum likelihood detector. In impulsive interference, the proposed detector also offers performance improvement over the detector optimized for Gaussian environment.

• Journal of Communications and Networks
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• v.8 no.2
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• pp.194-204
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• 2006

This contribution focuses on the maximum likelihood (ML) noncoherent synchronization of multi-antenna transceivers working in faded environments and employing ultra-wideband impulse radio (UWB-IR) transmit technology. In particular, the Cramer-Rao bound (CRB) is derived for the general case of multiple input multiple output (MIMO) UWB-IR systems and used to compare the ultimate performance of three basic transmit schemes, thereinafter referred to as single input multiple output (SIMO), MIMO equal signaling (MIMO-ES), and MIMO orthogonal signaling (MIMO-OS) ones. Thus, the noncoherent ML synchronizer is developed for the better performing transmit scheme (i.e., the SIMO one) and its performance is evaluated under both signal acquisition and tracking operating conditions. The performance gain in the synchronization of UWB- IR signals arising by the utilization of the multi-antenna technology is also evaluated.

• Journal of Communications and Networks
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• v.10 no.3
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• pp.297-300
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• 2008

The capacity of ultra-wideband (UWB) systems in presence of narrowband interference (NBI) is studied. By appropriately modifying the Shannon capacity formula, an analytical expression for the capacity of M-ary pulse position modulation (PPM) signals in the presence of NBI is obtained. Performance evaluation results for the capacity of such signals as a function of the NBI carrier frequency and power are also presented.