Article

# Spectrally Efficient UWB Pulse Shaping With Application in Orthogonal PSM

COPPE, Fed. Univ. of Rio de Janeiro

IEEE Transactions on Communications (Impact Factor: 1.98). 03/2007; DOI: 10.1109/TCOMM.2006.887493 Source: IEEE Xplore

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**ABSTRACT:**Choice of ultra wideband (UWB) pulse shapes has become an interesting challenge such that the spectral limits of the frequency band approved by the Federal Communications Commission (FCC) can be utilised efficiently. In this paper, we compare the efficiency of various UWB pulse shapes based upon their power spectral density (PSD) and autocorrelation functions (ACF). We propose a set of prolate spheroidal wave functions (PSWF) for a typical M-ary pulse shape modulation (PSM) scheme. In the process, we show closed form expressions for the ACF of PSWF-based UWB pulse shapes of different orders.Int. J. of Ultra Wideband Communications and Systems. 01/2014; 3(1):19 - 30. -
##### Article: Photonic Fractional-Order Differentiator Using an SOI Microring Resonator With an MMI Coupler

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**ABSTRACT:**An optically tunable fractional order temporal differentiator implemented using a silicon-on-isolator microring resonator with a multimode interference (MMI) coupler is proposed and experimentally demonstrated. Through changing the input polarization state, the self coupling coefficient and the loss factor of the designed ring resonator with the MM! coupler are changed. Correspondingly, the coupling regime is changed. Through changing the coupling regime from over-coupled to under-coupled regime, the phase shift in the resonance wavelength is changed from <;π to >π. This tunable phase shift is used to implement a tunable fractional order photonic differentiator with an order tunable from <;1 to 1. The proposed fractional order differentiator is demonstrated experimentally. A Gaussian pulse with a bandwidth of 45 GHz is temporally differentiated with a tunable order of 0.37, 0.67, 1, 1.2, and 1.3.IEEE Photonics Technology Letters 08/2013; 25(15):1408-1411. · 2.18 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**In this paper, we propose a novel orthogonal bi-pulse ultra-wideband (UWB) system, which uses an even pulse and an odd pulse to convey information symbols in an alternating manner. Due to the orthogonality of these pulses, their corresponding received waveforms remain orthogonal after propagating through multipath channels. Then we consider two major challenges in the realization of our proposed UWB system: timing synchronization and symbol demodulation. In particular, the idea of timing with dirty template (TDT) in [L. Yang, G.B. Giannakis, Timing Ultra-Wideband signals with dirty templates, IEEE Trans. on Commun. 53 (11) (2005) 1952-1963] is employed for timing synchronization and the noncoherent scheme in [L. Yang, G.B. Giannakis, A. Swami, Noncoherent Ultra-Wideband (de)modulation, IEEE Trans. Commun. 55 (4) (2007) 810-819] is used to bypass channel estimation. Both of these techniques are characterized by correlating adjacent waveform segments. In the implementation of these techniques, we will gradually reveal the advantages of our proposed system. The correlation of adjacent waveform segments only contains the information of a single symbol. This enables a significant enhancement of the synchronization speed of TDT when no training sequence is transmitted. For the same reason, our demodulation approach completely mitigates the inter-symbol interference (ISI) in the second paper referred to, above, and entails a simple demodulator even in the presence of unknown timing errors. Simulations are also carried out to corroborate our analysis.Physical Communication 12/2008; 1(4):237-247.

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