Study on a joint synchronization algorithm in timedomain for OFDM-UWB based indoor precision positioning system receiver

摘要

According to the basic principle of Orthogonal Frequency Division Multiplexing Ultra Wide Band (OFDM-UWB) based indoor precision positioning system, a Symbol Timing Synchronization (STS) algorithm with the high synchronization precision of only a few (1~3) sampling intervals is required to achieve indoor centimeter-level precision positioning. The performance of existing synchronization algorithms of OFDM-UWB system is so far to fit the rigorous needs of this indoor precision system. In this study, a new type of information frame format is designed, and based on which, a joint synchronization algorithm in time-domain for OFDM-UWB based indoor precision positioning system receiver is presented during the studying on STS. STS is the key technique of the joint synchronization algorithm, and at the same time, the joint algorithm comes into being by associating STS with Carrier Decimal Frequency Offset (CDFO), with Carrier Integer Frequency Offset (CIFO), and with Frame Timing Synchronization (FTS). The function verification and the performance analysis of the joint synchronization algorithm are made using MATLAB software in this study. The simulation results show that STS precision is only one sampling interval (1.89394ns) with a lower Signal Noise Ratio (SNR) of −15dB and carrier frequency offset disturb existing, which proves that the shortcomings of those existing STS algorithms that are easy to be disturbed by noise and frequency offset are overcame by the new joint synchronization algorithm, and proves that the joint synchronization algorithm meets the function requirements of the indoor positioning system fully. And at the same time, because these four synchronization technologies are integrated by the joint synchronization algorithm, the hardware resources can be saved effectively, the system costs can be reduced largely, and the anti-jamming performance and the stability of the receiver system can be enhanced hugely.