Analysis and Implementation of a Gaussian Addition IR-UWB Transmitter for Increased Spectral Efficiency

Abstract

This paper describes a technique to improve the spectral efficiency and increase the energy in the transmitted pulse of an impulse-radio, ultra-wideband (IR-UWB) transmitter utilizing bi-phase shift keying (BPSK) modulation and working in the frequency range of 3.1–10.6 GHz. Two Gaussian bi-phase pulses are produced and form the base-band signal. These two signals are delayed with respect to each other and are independently up-converted to a different region of the UWB spectrum. The two up-converted signals are then combined to form the final IR-UWB BPSK output signal. The IR-UWB output signal is analyzed in both the time domain and frequency domain to determine time-bandwidth product and spectral efficiency ( $$\eta $$ ). By combining the two up-converted gaussian signals, the spectral efficiency is increased to 77% and the time-bandwidth product of the output signal is 1.7. For a transmitter operating at a data rate of 250 Mbps, the energy per pulse of the output signal can be increased to 4.33 pJ while staying within the FCC spectral and power limits. This technique can also be used to produce a −30 dB notch at 5.9 GHz to further reduce any interference from an IEEE 802.11p Wifi signal.