UWB data link implementation and analysis.

摘要

Ultra-wideband (UWB) is an upcoming wireless technology for short-range, high data rate communication. The huge UWB spectrum can be utilized with an impulse radio. Achieving a good compromise between performance improvement and receiver complexity for practical UWB transmission system is a major challenge. In this thesis, first it is shown that both differentiation and pulse width variations affect the power spectral density (PSD) of the Gaussian, hermite pulses, and can be used to shape the transmitted waveform.;The information theoretical capacity of the UWB system is studied in different PSD pulse modulation schemes. The objective is first to reduce the power spectral density (PSD) of discrete components. It is verified that time hopping (TH), coding period in any modulation scheme has the effect of decreasing the number of power peaks, since the same power is distributed over large number of spectral lines. It is also shown that UWB system performance will be improved by combining pulse position modulation (PPM) and pulse amplitude modulation (PAM) which is called (PPAM).;Finally, I will briefly describe the performance of a single user UWB communication system with time hopping pulse position, TH-PPM, modulation by applying filter bank through the combination of maximum ratio combining (MRC) and a general matched filter receiver,(GMF). These receivers have been evaluated in several scenarios, such as Non line of sight (NLOS) and extremely non line of sight(ENLOS) and have had their performances compared by taking into account the BER, capacity of the channel and signal to interference radio(SIR). In this case, the UWB IEEE indoor channel model is considered.;In addition, it is shown that by increasing the pulse width and decreasing differentiation order numbers, the power will be shifted to the lower frequencies. In the case of hermite pulses, the orthogonal pulses can be assigned to different users in order to decrease the co-channel interference, and bit error rate (BER). Secondly, UWB pulse modulation schemes in the, additive white Gaussian noise (AWGN), channel model are evaluated.