# A _uv_-Cellular Network: Design, Implementation and Experiments  
[PERSON]  
1 College of Computer Science and Technology, Jilin University, Changchun 130012, China 1  
[PERSON]  
1 College of Computer Science and Technology, Jilin University, Changchun 130012, China 1  
[PERSON]  
2 Shenzhen Institute for Advanced Study, UESTC, Shenzhen 518110, China 2  
[PERSON]  
1 College of Computer Science and Technology, Jilin University, Changchun 130012, China 1  
[PERSON]  
1 College of Computer Science and Technology, Jilin University, Changchun 130012, China 1  
[PERSON]  
1 College of Computer Science and Technology, Jilin University, Changchun 130012, China 1  
[PERSON]  
1 College of Computer Science and Technology, Jilin University, Changchun 130012, China 1  
[PERSON]  
1 College of Computer Science and Technology, Jilin University, Changchun 130012, China 12  
that communicate with each other using acoustic signals for some targeted tasks, are the key enabling technology of large-scale IoUT. However, the terrestrial networking protocols would not work well in the underwater environment. And the limitations of underwater acoustic communication, such as long propagation delays, limited bandwidth, signal fading, asymmetric links, high error probability and extended multipath propagation [8; 9], are always the key factors affecting the performance and application development of UWSNs. In addition, compared to the past, the most significant increase of current task is in the desire for operational flexibility and agility in large-scale underwater network application scenarios. This means that more network nodes, both fixed and mobile, are needed to cover a wide area. Remote Operated Vehicles (ROVs), Autonomous Underwater Vehicles (AUVs), and other smart unmanned underwater mobile devices meet this urgent need and have been adapted to a wide range of application scenarios. However, the movement of network nodes makes it hard to maintain a reliable communication link from the source node to the destination node. The frequent changes of the network topology and the Doppler effect caused by the movement of nodes make communication and networking more difficult. Most of the research questions, however, have focused on systems with fixed sensors and devices which are deployed in a particular location without any form of mobility. Due to these issues, how to spontaneously establish a network and quickly find a relatively reliable path to forward information is one of the key problems of the large-scale UWSNs including both static and dynamic network nodes. In this paper, we propose a large-scale UWSN based on the cellular network architecture called _uw_-Cellular network. It is designed specifically for application scenarios where a large number of both fixed and mobile network nodes exist in a wide area to monitor the underwater environment. In this network, several fixed network nodes act as the Gateway node and the Base Station (BS) nodes, which together form the cellular network. And other nodes, as terminal nodes of the network, are distributed within the coverage area of the BS nodes. In particular, it is difficult to establish or maintain a stable and reliable communication link between each mobile terminal nodes and the BS nodes. Meanwhile, the _uw_-Cellular network faces both the problems of communication channel conflict avoidance and reliable data transmission. In order to solve these problems, we proposed a MAC protocol for the hierarchy network called SDDA for effective and efficient channel resource allocation. In addition, we also proposed a method called Communication Link Awareness (CLA) to evaluate the quality of the communication link status between two nodes. The main idea of this method is to transmitting information successfully with better efficiency in terms of delay based on the information available to each node. Strategies to guarantee data transmission reliability are also applied to _uw_-Cellular networks.