Efficient timing acquisition in dense multipath for UWB communications

In dense multipath environments, timing acquisition for UWB communications faces major challenges due to the stringent requirements to resolve and capture ultra-short transmitted pulses. This paper develops efficient maximum-likelihood (ML) acquisition methods that offer explicit design options to trade off acquisition accuracy and complexity. The proposed ML approach performs computationally affordable channel estimation based on a tapped delay line model, where the tap spacing is set at a low frame-level rate. By avoiding sub-pulse sampling, the proposed timing recovery scheme attains low complexity and fast acquisition speed, and at the same time enhances the estimation accuracy via the ML principle. Both the data-aided and non-data-aided schemes are derived.