On enhancing the transmission efficiency of modulated UWB signals under different emission standards

The stringent power limitation on ultra-wide band (UWB) free-space signaling raises the demand for efficient radio transmission, which requires a fine-spectrum compliance of the designed waveforms with regulation masks. In this paper, we exploit the benefits of carrier-based pulse generation techniques to improve the UWB spectrum performance under different emission standards, namely the Federal Communication Commission (FCC), Electronic Communications Committee (ECC), and Japanese masks. A modulated Gaussian pulse has shown to be an efficient UWB solution, as by using a carrier we can independently control the bandwidth and central frequency. We analytically find the best values for the Gaussian parameters, in the sense of maximizing the power efficiency without violating the authorized limits. The Sinc function has also shown to be a feasible alternative to Gaussian pulses, which can cover a large spectral area under emission masks due to its semi-flat frequency response. However, the long symbol duration required to collect the Sinc energy negatively influences the data rate. Applying linear combinations of modulated Gaussian and Sinc waveforms has been a key step to further enhance the spectral compatibility with the FCC, ECC, and Japanese standards, where the parameters of the elementary pulses have been adjusted using the interior point optimization algorithm.