Impacts Of Angle-Dependent Waveform Distortion On The Performance Of UWB Communication Systems

UWB (Ultra-wideband) communication is a new competitive technology in short distance and wireless communication. The performance of UWB communication is impacted by many factors. Waveform distorts inevitably while radiated by antennas. So it is without fail a factor influencing the performance of systems. Impacts of angle-dependant distortion are mainly studied in this paper. Certain reference can be provided for designs of UWB communication systems and UWB antennas.On the foundation of studying principle of UWB communication systems and the radiating characteristic of UWB antennas, we take the caliber antenna for example to study the angle-dependent waveforme distortion and impacts to the performance of DS-UWB. Then the optimal receiving template was chosen through comparing the bit error rate using different templates. At the end, impacts of angle-dependent waveforme distortion to three UWB communication systems:IR-UWB(Impulse Radio-UWB), DS-UWB (Direct sequence -UWB) and MB-OFDM (multiband- orthogonal frequency division multipexed) are compared.Analysis and simulation results indicate, in the channel of certain signal- noise ratio, the radiating waveform just against the caliber is the optimal template for DS-UWB. At this time, systems can realize credible transmission. In the channel of certain noise power density, the bit error rate is the lowest when the radiating waveform whose angle between observation point and caliber center is thirty-five is used as template for IR-UWB. But for DS-UWB, the bit error rate is also low when the radiating waveform whose angle between observation point and caliber center is larger than zero degree is used as template. For MB-OFDM, we use the transmitter and receiver as OFDM systems with radio frequency modem instead of correlation and imulation indicates the performance is almost not influenced by the angel-dependent waveform distortion.