Out-Degree Based Clock Synchronization In Wireless Networks Using Precision Time Protocol

Improving Energy Efficiency and Quality of Service in Wireless Body Area Sensor Network using Versatile Synchronization Guard Band Protocol

Abstract: In the last few years there has been a growing interest in Wireless Body Area Network (WBAN) due to its latency and enhance the health care features by continuously monitoring the condition of the patient and early identification of problems. A major difficulty has been occurring to design network such as Medium Access Control (MAC) protocol that primarily part of the WBANs for functioning in a well-organized way. Therefore, it limits the sensor node energy for Quality of Service (QOS) and life cycle of the network. Accordingly, this work introduces a Versatile Synchronization Guard Band Protocol (VSGP) namely VSGP, which deals with guard band (GB) in each time slot it reduces the interference of the transmitting signal and increase the efficiency of QOS and its energy. WBAN performed with more number of sensor nodes are connected to the coordinator. VSGP protocol is compared with two existing methods called Self Adaptive Guard Band (SAGB) and Traditional Guard Band protocol. Comparisons are made with time and packet flow of each transmission and energy per packet flow.

Tunable synchronization in duty-cycled wireless sensor networks

Abstract: In this work, we consider a duty-cycled wireless sensor network with the assumption that the on/off schedules are uncoordinated. In such networks, as all nodes may not be awake during the transmission of time synchronization messages, nodes will require to re-transmit the synchronization messages. Ideally a node should re-transmit for the maximum sleep duration to ensure that all nodes are synchronized. However, such a proposition will immensely increase the energy consumption of the nodes. Such a situation demands that there is an upper bound of the number of retransmissions. We refer to the time a node spends in re-transmission of the control message as broadcast duration. We ask the question, what should be the broadcast duration to ensure that a certain percentage of the available nodes are synchronized. The problem to estimate the broadcast duration is formulated so as to capture the probability threshold of the nodes being synchronized. Results show the proposed analytical model can predict the broadcast duration with a given lower error margin under real world conditions, thus demonstrating the efficiency of our solution.

Simulation of the IEEE 1588 Precision Time Protocol in OMNeT

Abstract: Real-time systems rely on a distributed global time base. As any physical clock device suffers from noise, it is necessary to provide some kind of clock synchronization to establish such a global time base. Different clock synchronization methods have been invented for individual application domains. The Precision Time Protocol (PTP), which is specified in IEEE 1588, is another interesting option. It targets local networks, where it is acceptable to assume small amounts of hardware support, and promises sub-microsecond precision. PTP provides many different implementation and configuration options, and thus the Design Space Exploration (DSE) is challenging. In this paper we discuss the implementation of realistic clock noise and its synchronization via PTP in OMNeT++. The components presented in this paper are intended to assist engineers with the configuration of PTP networks.

An Oscillator Model for High-Precision Synchronization Protocol Discrete Event Simulation

Abstract: : It is well known that a common notion of time in distributed systems can be used to ensure additional properties such as real-time behavior or the identification of the order of events As large-scale hardware testbeds for such systems are neither efficient nor easy to manage, discrete event simulations (DES) can be used to model such networks However, to ensure an exact behavior of such simulations, high precise models of the local clocks are also needed: the driving oscillators have to be modeled in a way that a DES simulation of a free-running node clock shows the same Allan deviation as the simulated counterpart This paper shows an approach to find a corresponding model for a simulator using white noise and a filter with the same power density spectrum as real-world oscillators

Self-Correcting Time Synchronization Support for Wireless Sensor Networks Targeting Applications on Internet of Things

Abstract: The Internet of Things is a collection of devices that communicate by exchanging a variety of data among them, in which time synchronization is needed for meaningful information creation and transmission. The robustness of the data transmissions becomes an issue, since most of these devices use wireless communication. This paper focuses in proposing and implementing a time synchronization service for low-power wireless sensor networks using low frequency real-time clocks in each node. This work presents the design, implementation and test of an adaptive algorithm, making the timing of the clocks converge as quickly as possible and after this convergence, keeping them most similar as possible. The goal is to achieve the best method that ensures right timing and still having low energy consumption. Experimental results provide evidence of the success in meeting this goal.