BER Performance of a TH-PPM UWB System in Different Scenarios using Fast Simulator

Time Hopping-Ultra Wideband (TH-UWB) is a relatively new technology that might has a big effect on improving wireless communication. This technology uses short pulses in order to transmit large amounts of digital data over a wide spectrum of frequency bands with a very low power. Unfortunately, in order to process ultra-wideband signals, an extremely large sampling rate is mandatory. In a straightforward approach, with the constant sampling rate, the length of the array that contains the bit samples can be very large, depending on the relationship between the duty cycle and the bit rate. Since this array should pass through the chain of blocks that model the channel and receiver responses, it is obvious that a large number of convolutions should be done. Thus, even in very fast workstations, the total computing time in order to estimate BER can be very high.
In this work, a complete Pulse Position Modulation (PPM) TH-UWB system is simulated using the high-speed system simulator. Comparing to previous simulators, sampling frequency can be as high as needed, since the simulation run-time does not depend on it. Transmitted signal is stored in the Transmitted Distorted Received (TDR) waveform vector, thus it is not necessary to operate with the signal samples in every simulation. The algorithm complexity is linear with the number of users, frames, multipath components, and rake fingers.
Therefore, algorithm used in this work can deal with channels with a large number of paths that are difficult to estimate using the existing algorithms. Thanks to this approach, low complexity for real time implementation and the good performance in terms of BER versus Signal to Noise Ratio (SNR) are achieved.
With this accurate flexible simulation model, the performance of the TH-UWB system and the impact of different factors of TH-UWB systems (the number of users, waveform design, time-hopping codes, channel models, receivers…) is analysed and a low BER in a real time application even in the presence of reach multipath environment is presented.