Research on UWB OFDM signal conversion

This paper presents a multi-bit discrete time sigma-delta converter for orthogonal frequency division multiplexing ultra wide band systems adopted by IEEE 802.15.3a and ECMA368 standard. An intact scheme of timing synchronization algorithm is also proposed for the receiver. The overall sigma-delta converter consists of two modulators. The low and high subbands of signal are operated by using third-order low pass and fourth-order band pass modulator respectively. The synchronization scheme is determined by algorithm improvement and simulation that frame detection and coarse timing are implemented by the maximum correlation method based on the first-band information of the preamble and fine timing is achieved by the minimum energy ratio method based on the information of all the three bands. The simulation results show that the proposed sigma-delta converter and synchronization algorithm are well suited for orthogonal frequency division multiplexing ultra wide band system and the system has better noise shaping and BER performance.