In this contribution the family of generalized multicarrier DS-CDMA (MC DS-CDMA) schemes [1] is investigated, when considering time-domain half-sine and raised-cosine chip waveforms, in addition to the rectangular chip waveform. Our results show that for a given subcarrier spacing the particular choice of the chip waveform has a substantial influence on the system’s performance. However, in the...

In this paper the novel method of “weighted OFDM” is addressed. Different types of weighting factors (including Rectangular, Bartlett, Gaussian, Raised cosine, Half-sin and Shanon) are considered. The impact of weighting of OFDM on the peak-to-average power ratio (PAPR) is investigated by means of simulation and is compared for the above mentioned weighting factors. Results show that by weighti...

In order to achieve frame synchronization in packetbased communication systems, a known sequence (preamble) is sent at the beginning of each packet. This paper presents a low power scheme for preamble detection using dynamic precision configuration. The proposed scheme is based on the observation that signal processing algorithms at the front end (including mixer, Square root raised cosine (SRR...

This paper presents the implementation of an undersampled LC bandpass Σ∆ ADC with a raised-cosine feedback DAC. It directly converts after the LNA a signal centered in the ISM band at 2.442GHz with a sampling frequency of 3.256GHz. This circuit has been fabricated in a 130nm CMOS process, it occupies an area of 0.27mm and is operating at a supply voltage of 1.3V. The Signal to Noise and Distort...

In this work, we analyze the effect of different pulse shaping filters on the performance of the asynchronous DS-CDMA systems employing long spreading sequences over Rayleigh-fading channels. We numerically evaluated and compared the performance of rectangular pulse and square root raised cosine pulses with different rolloff factors for conventional receiver and multiuser detectors. Our work ju...

This paper introduces an extended Kalman filter (EKF) based algorithm for the estimation of closely-spaced path delays and complex coefficients in WCDMA environments. The EKF might be applied either at sample or at symbol level. The model parameters and the sensitivity to the initialization conditions are described for a practical downlink WCDMA scenario, employing root raised cosine pulse shap...

In this paper we consider the information rates of faster than Nyquist (FTN) signaling schemes. We consider binary, quaternary and octal schemes that use root raised cosine pulses. Lower and upper bounds to the information rates are given. The main result is that the lower bounds are often above the information rates for standard Nyquist signaling schemes. This implies that FTN must be superior...

In this paper, a novel digital modulation technique based on spiking neuron models is proposed. Thanks to the extremely simple and low-power spiking neuron circuits, this modulation scheme allows a less complex receiver at the cost of a more complicated transmitter. Accordingly, it is a good candidate for downlink transmission. Since the transmitted signal is generated based on Shannon’s interp...

We propose an easy and efficient way to analytically design densely dispersion-managed fiber systems for ultrafast optical communications. This analytical design is based on the exact solution of the variational equations derived from the nonlinear Schrödinger equation by use of either a Gaussian or a raised-cosine (RC) Ansatz. For the input pulses of dispersion-managed optical fiber transmissi...

Analytic approximations are presented for the response of buckling-mode electrothermal actuators with very slender beams a width-to-length ratio W/L≤0.001 type found in nanoelectromechanical systems (NEMS). The results as closed-form solutions to Euler beam bending theory rather than by an iterative numerical solution or time-consuming finite element analysis. Expressions transverse deflections...