Differential Code-Shifted Reference Impulse-Radio Ultra-Wideband Receiver: Signal Strength Adjustment and Implementation

Abstract

IR-UWB is a wireless system, which sends information data with pulses that have rapid rising and falling time and very short duration of nanosecond or less. However, due to varying communication channel conditions, amplitude of the received signal is not at a constant level. Therefore, automatic signal strength adjustment is required to equalize the impact of variations of the channel conditions. In this thesis, two approaches based on automatic gain control technique are proposed. The first design is a feed-forward automatic gain control system working at baseband. The second design is a feedback automatic gain control system operating at radio or microwave frequency. The corresponding simulation and implementation results are provided to validate the designs. The proposed designs present signal strength controls for impulse-based transceiver systems which are not often addressed in the literature. It is found that the first design does not work well in reality due to the fact that it essentially operates in the baseband and has no impact on the strong or weak signals right after the receiver antenna. The second design functions quite well and presents a dynamic range of 179mV to 1.062V. As a result, it is the choice of this thesis work.