Among various indoor positioning technologies, impulse-radio UWB is a promising technique to provide indoor positioning and tracking services with high precision. Because UWB regulations turned to imposing restrictions on UWB low band, UWB high band becomes attractive for enabling simple and low cost implementation. However, UWB high band endures much larger propagation loss than UWB low band. In this paper, we propose two separated methods to compensate the deficiency of high band in propagation. With the first method, we bundle several IR-UWB modules to increase the average transmission power, while an adaptive detection threshold is introduced at the receiver to raise receiving sensitivity with the second method. We respectively implement each of these two proposed methods and evaluate their performance through measurements in laboratory. The results show that each of them achieves about 7dB gains in signal power. Furthermore, positioning performance of these two proposed methods are evaluated and compared through field measurements in an indoor sports land.

The paper presents capability of signal detection for realizing coexistence between broadband wireless access (BWA) systems and ultra wideband (UWB) devices. The capability is experimentally evaluated for baseband signals of downlink (DL) in both mobile WiMAX and 3GPP LTE. An UWB receiver based on fast Fourier transform (FFT) compliant with MB-OFDM standard is implemented as a detector of the BWA signals. The capability is evaluated in terms of elapsed time required to achieve signal detection with probability of 99% by the implemented FFT-based UWB receiver at different conditions of the receiver. Decisions on the signal detection are made by the simplest method which is by setting a threshold which is determined by noise floor of the receiver as reference. The experiments have been conducted though baseband signals for both AWGN and multipath fading channels without any synchronization between the DL signals and UWB receiver. In AWGN environment, results show that the elapsed time depends on the duty ratio of the DL signal to be detected, however, the correlation between the required time and duty ratio is not linear since their envelopes of the DL signals are not constant. In multipath fading environments based on channel models commonly employed as mobile radio environments, the required time for the signal detection becomes as 17 times longer than that in AWGN due to its signal attenuation. For robust signal detection in multipath fading environments, it has been revealed that the number of quantization bits at ADC is crucial through the experiments.