We propose the "Two-Step Search scheme with Linear search based Second step (TSS-LS)" by improving the conventional "Two-Step Search scheme with Bit reversal search based Second step (TSS-BS)" for reliable as well as rapid acquisition of Ultra Wide Band (UWB) signals in multipath channels. The proposed TSS-LS utilizes two different thresholds and search windows to achieve fast acquisition. Furthermore, unlike the TSS-BS in which the bit reversal algorithm is applied in both steps, the linear search is adopted for the second step in the proposed TSS-LS to correctly find the starting point in the range of effective delay spread of the multipath channels, and to obtain reliable bit error rate performance of the UWB systems.

TR-UWB (Transmitted Reference-Ultra Wide Band) systems have low system complexity since they transmit data with the corresponding reference signals and demodulate the data through correlation using these received signals. However, the BER (Bit Error Rate) performance in the conventional TR-UWB systems is sensitive to the SNR (Signal-to-Noise Ratio) of the reference templates used in the correlator. We propose an improved recursive transceiver structure that effectively minimizes the BER for TR-UWB systems by increasing the SNR of reference templates.

In order to effectively improve the BER (Bit Error Rate) performance of noncoherent IR-UWB (Impulse Radio Ultra Wide Band) systems utilizing 2PPM (Binary Pulse Position Modulation), we propose a selective signal combining scheme which performs selective combination of received signals by estimating the SNR (Signal-to-Noise Ratio) of the energies during the pulse width interval.

We propose a selective detection scheme based on pulse repetition considering both BER (Bit Error Rate) performance and complexity in coherent UWB (Ultra Wide Band) systems. To take system complexity into account, the proposed scheme transmits the UWB signals by pulse repetition at the transmitter, like conventional PRC (Pulse Repetition Coding). However, to effectively improve BER performance of the system, the proposed scheme performs selective detection by estimating the SNR (Signal-to-Noise Ratio) of the received pulse-repeated signal at the UWB receiver.

We propose an improved TDoA (Time Difference of Arrival) localization scheme based on PSO (Particle Swarm Optimization) in UWB (Ultra Wide Band) systems. The proposed scheme is composed of two steps: the re-estimation of TDoA parameters and the re-localization of tag position. In both steps, the PSO algorithm is employed to improve the performance. In the first step, the proposed scheme re-estimates the TDoA parameters obtained by traditional TDoA localization to reduce the TDoA estimation error. In the second step, the proposed scheme with the TDoA parameters estimated in the first step, re-localizes the tag to minimize the location error. Simulation results show that the proposed scheme achieves better location performance than the traditional TDoA localization in various channel environments.