Improved Time Synchronization Algorithm Research Articles

Improved Time-Synchronization Algorithm Based on Direct Compensation of Disturbance Effects.

In this paper, an improved time-synchronization algorithm is proposed. The improvement of time synchronizing performance was achieved by introducing a stochastic model-based direct compensation of the disturbance effects appearing in the IEEE 1588 Precision Time Protocol (PTP)-based time synchronization system. A dynamic model of PTP clock system was obtained by reflecting the three major sources of disturbances, i.e., clock frequency drift, clock rate offset, and network noise. With the application of the dynamic model of the PTP clock system, the effects of the disturbances can be effectively eliminated in the PTP time synchronization control loop. Computer simulations are performed to verify the performance of the proposed time synchronization algorithm by applying the various types of disturbances, including network noise and clock drift. The simulation results are compared with those of other representative time synchronization algorithms, i.e., IEEE 1588 PTP algorithm and Kalman-filter-based algorithm. It is shown that the proposed algorithm improves time synchronizing performance up to 84% with respect to that of the Kalman-filter-based synchronization algorithm when simulated with colored noise type disturbances. The proposed time synchronization algorithm is expected to contribute for the realization of future Ethernet-based industry-plant monitoring and control including IEC 61850-based digital substation.

Photovoltaic Modules Monitoring Based on WSN With Improved Time Synchronization

In order to avoid clock skew in WSN (Wireless Sensor Networks) for large-scale photovoltaic modules monitoring, an improved time synchronization algorithm, TSP-GDM (Time Synchronization Protocol with Gaussian Delay Model) is proposed in this paper. Interdependence of local time stamps is established between network nodes according to a linear clock model. Local exchange and share of local time stamps in nodes are achieved by means of wireless transmission. An estimation method with the Gaussian Delay Model is designed to deal with the estimation problems of the node clock offset. The synchronization accuracy of the proposed method is verified with the MATLAB simulation. It is found that TSP-GDM can be applied to synchronous topology of large-scale photovoltaic modules monitoring with a higher synchronization accuracy. Compared to RBS (Reference Broadcast Synchronization), TPSN (Timing-synchronization Protocol for Sensor Networks) and RTSP (Recursive Time-Sync Protocol for WSN), its synchronization accuracy in an inner layer has been increased by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$22.57~\mu \text{s}$ </tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$15.7~\mu \text{s}$ </tex-math></inline-formula> and 4.26 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> respectively.

An Improved Time Synchronization Algorithm for Wireless Sensor Networks

Wireless sensor network (WSN) has been paid more and more attention to by the international academic and industrial fields. What’s more, it has become a hot research topic with great attention and expectations. There are a lot of technical problems involved in wireless sensor networks, among which, time synchronization technology is one of the supporting technologies in wireless sensor networks. And it is rather essential for the application of wireless sensor network. Two classical time synchronization algorithms are introduced and their advantages and disadvantages are compared. Based on the existing algorithms, an improved time synchronization algorithm is put forward. The improved algorithm was simulated by NS2. The results showed that the proposed algorithm had better time synchronization accuracy and lower network cost than RBS and TPSN algorithm. In summary, the improved time synchronization algorithm has a rather good performance.

Self-Correcting Time Synchronization Based on Cross Layer for Wireless Sensor Network

Due to energy restrictions, node distribution density and hardware computing power etc., the traditional time synchronization mechanism is not suitable for wireless sensor network. The paper discussed the main reason that caused asynchronization and proposed an improved time synchronization algorithm based on cross layer optimization for wireless sensor network. Considering the stability of crystal oscillation and the linearity of crystal deviation in the physical layer, the improved time synchronization mechanism implemented a self-correction by the cross-layer MAC protocol. Estimating the crystal oscillation drift, the crystal deviation had been self-corrected just by a few times data broadcast. The experiment on the MCU Si1000 physical layer platform has demonstrated the practicability of the algorithm. The synchronization algorithm is able to keep a stable network operation in the way of extending the synchronization period and reducing the synchronization cost. The synchronization mechanism is applicable to the active acquisition network, especially the realtime one.

An Improved OFDM Timing Synchronization Algorithm

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier communication system and the system is very sensitive to synchronization errors. The problem that synchronization is not accurate can reduce the system performance largely. Based on the research of Schmidl &amp; Cox and Minn algorithms, the paper proposed an improved timing synchronization algorithm by using the new training sequence in the frequency domain. The improved algorithm eliminates the peak platform problem and side lobe peak problem of the conventional synchronization algorithms in this article. The simulation at MATLAB shows that the improved algorithm overcomes the problems of the conventional algorithms and the timing judgment curve of the improved algorithm also has a very sharp peak at the timing synchronization position, compared with the conventional algorithm. So, the timing synchronization performance of the algorithm is better.

The Research of WSN Time Synchronization Algorithm Based on Clustering Network

In order to solve time synchronization problem of wireless sensor network, combined with the broadcast characteristics of wireless transmission and bi-directional message mechanism and the characteristics of clustering network, this paper presents an improved time synchronization algorithm HLTN based on clustering network and the simulation experiment by NS-2 simulation platform and analyzed the results.