Research On The TOA Estimation Algorithm Based On IR-UWB System

Impulse Radio Ultra-Wideband(IR-UWB) is an emerging wireless communication technology, which uses nanosecond pulse sequences with high temporal resolution and has the accurate ranging and positioning capability in low data rate, as well as good robustness in a dense environment. At the same time, its characteristic of low power consumption and cost makes Ultra-Wideband technology quickly become the focus of many countries and research organizations. There is no doubt that it has broad prospects in the field of wireless communication.Firstly, this paper gives an introduction of the background and significance of theresearch, and analyses the current Ultra-Wideband positioning technology at homeand abroad in detail. Secondly, the positioning methods of existing wirelesspositioning technologies are explained, among which The Time of Arrival(TOA) wayis attached great importance in comparison with other methods. It’s indicated that themultipath phenomena and non-light of light are the main reason of ranging error. Thenthe signal pulse shaping of IR-UWB system, modulation modes, receiver technology,and channel model are analyzed. In this paper, the Gaussian pulse in timehopping-pulse position modulation(TH-PPM) is transmitted by antennas through theIEEE802.15.4a channel to the receiver. The receiving mode includes the coherent oneand the non-coherent one. The former based on matching filtering generally requiresprecise local templates, but the latter is based on energy detection and has lowsampling rate and low complexity. Next, the main section of the paper discusses thecommon TOA estimation algorithms.TOA estimation tends to detect the direct path(DP) of the signal, which isgenerally the strongest path under the condition of visibility. However, in the midstenvironment with severe multipath phenomenon, the DP is no longer the strongest one,and it becomes more difficult to make the estimation. Meanwhile, the presence of NLOS increases the additional propagation delay of DP. The key point of rangingalgorithms is to set a reasonable and precise detection threshold. Given all this, thepaper proposes a detection algorithm based on the statistical parameters of thereceived signal. A joint param is created to reflect the changes of the optimalthreshold under different signal to noise radio(SNR). Simulation results show that theranging accuracy is superior to several classical TOA estimation algorithms in CM1and CM2channels for different sampling intervals.Finally, the paper comes to a conclusion and analyses the necessity of furtherresearch in the near future according to some weak points of this paper.