Performance Of Delay Locked Loop Research Articles

An analytical model of code-tracking performance for next-generation GNSS modulations

Precorrelation bandlimiting, sampling, and quantization (BSQ) are three fundamental functions of receivers for global navigation satellite system (GNSS) signal processing. Analytical models have been developed to evaluate the implementation losses due to different combinations of these parameters for legacy modulations such as BPSK. However, the performance metric was losses of effective carrier-to-noise ratio in dB, instead of performance degradation of a delay-locked loop (DLL) used for code-tracking. This paper proposes an analytical model to predict the DLL performance with the loss of RMS tracking error in meters as the performance metrics. The signal model & assumptions and canonical form of DLL are first introduced. Then, analytical model is derived for DLL tracking accuracy and the performance metrics, tracking loss is defined. Finally, simulation results of two next-generation modulations for GPS and Galileo, namely CBOC and TMBOC, are presented.

Pseudonoise code tracking loop for a CDMA system with imperfect power control

AbstractIn this paper, performance of a pseudonoise (PN) code tracking loop is analysed and simulated for a direct‐sequence/code‐division‐multiple‐access (DS/CDMA) system with imperfect power control in a multipath fading channel. A non‐coherent first‐order delay‐locked loop (DLL) is considered as a PN code tracking loop. Power control error is modelled as a log‐normally distributed random variable. The multipath fading channel is modelled as a two‐ray Rayleigh fading model that is typically applied to land mobile communication environments. The tracking performance of DLL is evaluated in terms of tracking jitter and mean‐time‐to‐lose‐lock (MTLL). From the simulation results, it is shown that for smaller discriminator offset, tracking jitter performance is improved while MTLL performance is degraded. It is shown that large power control error and heavy shadowing substantially degrade the PN tracking performance. Therefore, an accurate power control scheme is very essential to compensate for fading and shadowing for a DS/CDMA system. The extension of analysis to higher‐order loop models is very straightforward. The analysis in this paper can be applied to design the PN code tracking loop for a DS/CDMA system. Copyright © 2001 John Wiley & Sons, Ltd.

Performance of delay-lock loop in multiplepseudo-noise signals

The extension of the concept of delay-lock loop (DLL) tracking of pseudonoise (PN) signals, is considered. Specifically, the performance of DLL in multiple PN signals is described. The application area of a mobile position determination system which uses multiple PN signals is briefly described.

Performance of dll for PN sequences with bit errors

AbstractTracking performance of DLL (Delay‐Lock Loop) for PN sequences with bit errors is discussed and the relationship between the average bit error rate and the normalized r.m.s. tracking error of one‐Δ DLL, is analyzed using the concept of “error sequence.” As a result, it is clarified that the tracking error is nearly proportional to the average bit error rate pe when the loop band width is narrow and is nearly proportional to Pe when the loop band width is wide. The performance of BPSKC (Binary Phase Shift Keyed Correlation) system is analyzed and compared with conventional noise residual systems. It is demonstrated that the BPSKC system is disadvantageous for the input SNR below a certain level but it has some advantage over other systems for the input SNR beyond this level.