For wireless transmission, the channel estimation is necessary to improve the performance of receiver. In the ultra-wideband (UWB) wireless systems, there are two practicable modulation schemes: orthogonal frequency-division multiplexing (OFDM) and single-carrier direct-sequence UWB (DS-UWB). The OFDM based scheme is an attractive mode because it can capture the multipath energy more efficientl...

Ultra Wideband (UWB) system is overlapped with various wireless systems, such as WLAN, WiMax and UMTS, which limits the use of UWB. Cognitive Radio (CR) enables UWB systems to efficiently use the overlapped spectrum without causing interference to other wireless systems. In this paper, we focuses on the low-complexity joint optimization algorithm design with respect to transmit power allocation...

Ultra wideband (UWB) radio communication is capable of a high data rate with low radiated power. A key issue for UWB design is LNA input/output matching over a wide bandwidth: 3 to 5GHz for the lower band and 3 to 10GHz for the entire band. Several UWB LNAs have been proposed in recent years. The UWB CMOS LNA presented in [1] employs a Chebyshev filter for input matching and a source follower f...

Ultra-wideband (UWB)system communicates with a base-band signal composed of sub-nanosecond pulses (referred to as monocycle). A new monocycle shape based on wavelet is presented whose spectrum meets the Federal Communication Commission (FCC) spectral mask. In many literatures, it is usually assumed that the synchronization has been achieved between the receiver and the transmitter, actually it ...

In this paper, a range difference estimation technique with NLOS error mitigation by using biased Kalman filter for ultra-wideband (UWB) environments is presented. NLOS error is considered one of the major error sources in wireless location systems. To improve TDOA location accuracy in UWB location systems, NLOS identification and mitigation techniques suitable for UWB systems are derived. Kalm...

This paper presents a low-cost Ultra Wideband (UWB) pulse generator that can vary the pulse duration digitally by using a Step Recovery Diode (SRD), microstrip transmission lines and PIN diodes. First, a sharp edge is generated by using a SRD circuitry. Then a pulse is formed from the sharp edge through the use of transmission lines and the PIN diodes. Based on the number of transmission lines ...

The ultra wideband (UWB) radio has been a promising technology for the short range wireless systems. The frequencydependent behavior of the antennas are not negligible in UWB systems, especially in the impulse radio (IR). This letter presents the extension of the Friis’ transmission formula for the link budget estimation of UWB radio, considering the transmit signal waveform and the imperfect a...

The capacity of time-hopping pulse position modulation (PPM) and pulse amplitude modulation (PAM) for an ultra-wideband (UWB) communication system is investigated based on the multipath fading statistics of UWB indoor wireless channels. A frequency-selective fading channel is considered for both single-user and multiple-user UWB wireless systems. A Gaussian approximation based on the single-use...

© 2013 Jung-Nam Lee et al. 1075 http://dx.doi.org/10.4218/etrij.13.0113.0472 This paper describes an ultra-wideband (UWB) antenna that uses a ring resonator concept. The proposed antenna can operate in the entire UWB, and the IEEE 802.11a frequency band can be rejected by inserting a notch stub into the ring resonator. The experiment results indicate that the measured impedance bandwidth of the...

In this paper we study the information theoretic capacity of Pulse Position Modulation (PPM) Ultra Wideband (UWB) communications for single user channels. The capacity is studied with a link impulse response with delay spread and Inter Pulse Interference (IPI). The objective is to consider the effect of IPI on capacity and quantify the capacity with IPI. An expression for the signal-tonoise rat...