Integrated Time Synchronization and Multiple Access Protocol for Underwater Acoustic Sensor Networks

Zhigang Jin,Mengge Ding,Yongmei Luo,Shuo Li

doi:10.1109/access.2019.2931117

Zhigang Jin, Mengge Ding + Show 2 more

Open Access

https://doi.org/10.1109/access.2019.2931117

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Abstract

Due to the limited energy and mobility of the traditional sensor nodes, autonomous underwater glider (AUG) is widely used in underwater acoustic sensor networks to achieve long-term and large-scale marine environmental monitoring. In the communication between AUGs, time synchronization (TS) and multiple access control process (MACP) both need control frames to guarantee the data transmission. However, the independent execution of these two processes causes the control frames to be sent repeatedly, resulting in more transmission delay and energy cost. In order to communicate between AUGs more efficiently, an integrated TS with multiple access (TSMA) protocol is proposed in this paper. Within the AUG group, an AUG is selected as the beacon node to provide a standard clock to complete the intra-group TS process, while inter-group TS adopts the non-beacon synchronization method. In the TS process, the effect of the relative movement between AUGs is considered to improve the accuracy of synchronization. Besides, we create a new control frame that can fuse the message exchange of TS and MACP. Simulation results show that TSMA has a better performance in terms of the packet delivery fraction, synchronization errors, and energy efficiency.

Highlights

In the past few years, the application of underwater acoustic sensor networks (UASNs) in environmental monitoring, marine resource exploration, and national defense security has been highly valued by academic and industrial circles [1], [2].the communication environment in UASNs is more complicated than terrestrial wireless sensor networks (TWSNs)
SIMULATION RESULTS we evaluate the performance on packet delivery fraction (PDF) of the TS with multiple access (TSMA) protocol and compare it with MU-Sync [9] and the G-media access control (MAC) protocol with nonsynchronization (No-Sync) [11] in the underwater acoustic simulation software Aqua-Sim which developed with C++ and OTCL scripting language
In UASNs, it is a key challenge to establish efficient time synchronization (TS) and multiple access control for Autonomous underwater glider (AUG), while separating TS and multiple-access data transmission (MADT) processes both need exchange the control frames to guarantee the data transmission, which increases the number of unnecessary exchanges of control frames and causes the waste of time and energy resources

Summary

INTRODUCTION

In the past few years, the application of underwater acoustic sensor networks (UASNs) in environmental monitoring, marine resource exploration, and national defense security has been highly valued by academic and industrial circles [1], [2]. At the same time, separating TS and data transmission increases the number of messages exchanged, resulting in greater time consumption and energy consumption and lower energy efficiency To solve this problem, this paper proposes a TSMA protocol which combines TS process and MACP. Doppler factor estimation is used to calculate the relative speed between members, the clock skew and the clock offset based on the time stamp obtained considering the mobility of the AUG and the time error caused by the synchronization. By this way, the accuracy of IGTS is increased. Spread in the same way until the entire communication link remains synchronized

MULTIPLE-ACCESS DATA TRANSMISSION PROCESS

SIMULATION RESULTS

CONCLUSION