Non-NCO Periodical-Pilot-Assisted Tracking Method for Practical High-Rate DS-UWB Systems

Traditional Delay-Locked-Loop (DLL) method can be hardly used in high-rate Direct-Sequence Ultra-Wideband (DS-UWB) systems due to dense multipath environment, low spreading factor and high-frequency clock. Most of the existing researches on tracking in UWB scenario focus on low-rate Impulse-Radio UWB (IR-UWB). In this paper, a non-Numerical Controlled Oscillator (NCO) periodical-pilot-assisted tracking method is proposed for practical high-rate DS-UWB systems. Analytical expressions of Equivalent Probability Density Function (EPDF) of timing error in locked state, Mean Square Error (MSE, or termed timing jitter) and Mean Time to Lose Lock (MTLL) are derived. Numerical results are presented, and then confirmed by means of extensive computer simulation results. These results corroborate our theoretical analysis, and show performance superiority of the proposed method over traditional DLL. Additionally, this proposed method has been used and justified in our practical DS-UWB system.