Time Synchronization for Underwater Cellular Networks

Underwater wireless communication is greatly attractive to explore and develop because there is a vast unexploited area under the sea. Therefore, the effect of skew is not negligible when we use sound waves in water for wireless communication. For underwater sensor or cellular networks, some time synchronization protocols which consider the skew such as Time Synchronization for High Latency (TSHL) have been proposed to overcome the environmental limitation. TSHL has two phases. The first one is a skew estimation step with time stamps and linear regression. We propose a new skew estimation with a time interval of beacon messages and Root Mean Square which is simpler than linear regression of TSHL. Our Time Synchronization for Underwater Cellular Networks (TSUC) confirms really comparable accuracy with TSHL but much simpler in skew estimation. Additionally, we think of resynchronization too. Our second idea is using sliding window to reuse the former estimated skew data. Therefore, TSUC can reduce latency in re-synchronization. This is important since it makes TSUC appropriate for cellular networks.