Pulse Shaping Designing & The Performance Analysis Of The IR-UWB System

The impulse radio ultra wideband (IR-UWB) technology adopts ultra-short pulses to transmit information, and has a huge capacity to serve for high data rate. The pulse shaping technology and the system performance in IR-UWB are studied in this thesis. The primary contents of the thesis are as following:Gaussian pulse, Modified Hermite pulse, and Prolate Sphere Wave Functions pulse are introduced. Two different approaches, such as random coefficient combination and the coefficient combination based on LSE, are employed to choose the combination coefficients and then, the best combination coefficient is made certain according to the FCC UWB indoor spectral mask. The pulses derived from Gaussian pulse are used as basis functions to form the combination pulses through two coefficient combination ways. The simulation results show that the power spectrum density of the combined pulses approachs to the indoor spectral mask. The spectrum utilization rate of the combined pulses achieves more than ninety precent, and is much higher than that of the second Gaussian derivative pulse.For the Time Hopping UWB with Binary Pulse Position Modulation (2PPM-TH-UWB) system is compared with, the Direct Spread UWB with Binary Pulse Amplitude Modulation (2PAM-DS-UWB) system, and the Time Hopping UWB with Binary Pulse Shape Modulation (2PAM-TH-UWB) system, the comparison of their Bit Error Rate(BER) is carried out over the additive white Gaussian noise (AWGN) channels. The performance of the former two systems, which respectively employ the second Gaussian derivative pulse, the random coefficient combination pulse, and the coefficient combination pulse based on LSE as UWB signals, is given. By using the second Gaussian derivative pulse, the random coefficient combination pulse, and the coefficient combination pulse based on LSE, the performance of 2PPM-TH-UWB systems with Rake receiver over muitipath channels is analyzed. Over AWGN channels and multipath channels, the simulation of the Time Hopping UWB with Binary Pulse Shape Modulation (2PSM-TH-UWB) systems is made through ultilizing the Gaussian orthogonal pulses and the orthogonal eigenvalue pulses. The result shows that the latter has better performance.Based on the Standard Gaussian Approximation (SGA), the formula of Bit Error Rate (BER) in the 2PSM-THMA UWB system is deduced. Under ideal power control, the 2PSM-THMA UWB systems with different numbers of interference users and different kinds of bit rate are discussed. The simulation result reveals that the system performance can be improved through increasing the energy or power of every transmitted pulse, and reducing the bit rate. Futhermore, the performance of UWB receiver in the multiuser interference circumstance is simulated. The results show that the BER performance of the system is consistent with the theoretic result. Moreover, their approach effect is better when the number of interference users increases.