QPSK Modulation Scheme Based on Orthogonal Gaussian Pulses for IR-UWB Communication Systems

Abstract

A new impulse radio-ultra wideband (IR-UWB) communication system with quadrature phase shift keying (QPSK) modulation scheme was presented in this research. The system utilized orthogonal property of fourth- and fifth-order derivatives of Gaussian pulses for modulation and time hopping (TH) multiple-access scheme. This system was compared with conventional TH-PPM and TH-BPSK systems at the same condition. The simulation results in multipath channel showed that the proposed system can provide better bit rate performance compared with the conventional IR-UWB system. A very low power and low complexity circuit for generation of the fourth-order derivative of Gaussian pulse was also proposed. The circuits of fourth- and fifth-order derivatives of Gaussian pulses were simulated using a 0.18[Formula: see text][Formula: see text]m CMOS technology. The core chip size was only 0.015[Formula: see text]mm2. The output amplitude pulse yielded 135[Formula: see text]mV peak to peak under a supply voltage of 1.8[Formula: see text]V. The energy consumption of the fourth- and fifth-order derivatives of Gaussian pulses circuits were 8[Formula: see text]pJ/pulse for 200[Formula: see text]MHz pulse-repeating frequency (PRF).