On The Performance Analysis Of USB System With Permutated Time-Hopping Sequences

Ultra Wide Band (UWB) is a new technology for wireless communication developed in recent years. It is very different from other wireless communication technology. It has the following features, such as large communication capacity, low radiation power density, good ability against Multi-path interference, simple structure and excellent security performance. UWB technology is a new exploration of the use of radio spectrum resource and it inaugurate a new field of time domain application of electromagnetic wave. In UWB wireless communication system, the users share the time domain resource, and the time slot which can be used to transmit the user's message is controlled by the time-hopping sequences. The good time-hopping sequences will decrease the multi-access-interference caused by sharing the channel and enhance the system performance, so time-hopping sequences plays an important role in UWB communication system.In this thesis, time-hopping sequences based on permutation-sequences are firstly studied and their fundamental of math theory and generation method are introduced. Correlation property of timing-hopping sequences based on permutation-sequences relied on fractional linear transformation and the number of sequences of sequences families generated from them are analyzed. Secondly, the performance of time-hopping sequences based on permutation-sequences, quadratic congruence sequences, cubic congruence sequences and hyperbolic congruence sequences are compared. In addition, an equivalent expressing method of correlation function of time-hopping sequences is introduced and by studying the characteristic of it, an upper bound of correlation function of time-hopping sequences is presented. Then, the channel model of time-hopping UWB communication system is established and the decision method of signal in the receiver is selected. Besides, math model of correlation receiving is established and antinoise performance of correlation receiving is analyzed. Finally, simulation of UWB system performance of some sequences, such as time-hopping sequences based onpermutation-sequences, quadratic congruence sequences, cubic congruence sequences and hyperbolic congruence sequences is done separately in PPM modulation mode and BPSK modulation mode. The result shows that time-hopping sequences based on permutation-sequences have excellent correlation property and plentiful sequence number. They can be applied to time-hopping UWB communication system.