| With the rapid development of wireless sensor networks and the growing importance of maritime rights and interests, as well as the emergence of the development of marine economic boom, underwater sensor networks has become a hot research topic in the sensor networks.Underwater sensor networks and terrestrial wireless sensor networks are very different, and the most important one is the means of communication. Even though they all belong to wireless communications domain, the terrestrial wireless sensor networks use radio for communication, meanwhile the underwater wireless sensor networks using underwater acoustic communication. Although the wireless channel is not good than wired channel at the communication rate, channel quality, it has a very high data transmission rate and communication quality compared to the underwater channel. The underwater channel is regarded as the worst of the wireless communication channel. In addition, the underwater channel also has a high-delay in communication. Its propagation speed is only 1500m/s, compared with terrestrial radio signal propagation speed of a full lower five orders of magnitude.The channel characteristics of underwater sensor networks have brought challenges to researchers, and another important issue associated with it is the underwater sensor networks testing and validation issues. Underwater sensor networks research, whether in hardware or software aspects, whether it is a simple point to point communication experiments, or multi-node networking test, test and verification can not be separated from the researchers. Testing and validation can be divided into software simulation and hardware simulation and actual test of the marine environment. In the laboratory the use of software simulation, the cost is very low. But not all of the tests are suitable for software simulation, because the software simulation will be affected by the simulation environment and the accuracy of the model itself, the software simulation is only applied to those tests depending less on hardware and environments acquirements. For those tests which rely heavily on hardware, it is best combining with hardware platform which can be configurable to different environment, for example, such as those tests which directly related to modifying the underlying parameters of the hardware. Another group of tests are more demanding communications environment, and many protocols verification, need to go to the actual testing and validation of the marine environment. This is because the nature of underwater sensor networks which eventually be applied to the underwater environment, and because of the complexity of the underwater physical environment, taking advantage of a practical underwater test platform can be configured to achieve this goal is clearly the most ideal. However, the tests for underwater sensor networks are expensive, and will need a lot of manpower and material resources. How to design and implement a physical testing platform at sea to meet the testing needs of the underwater underwater sensor networsk is an important research topic.The subject of this paper is to study the underwater sensor network test-bed system at sea according to the main characteristics of underwater sensor networks, and the main research contents of this paper include:1. According to the needs of the underwater experiment, we designed and produced a double-headed hardware node. The hardware node includes two parts:the node above the water and the node underwater. The node above water using TelosB, and the underwater node is desgined by us. The hardware nodes are the basis for our underwater test platform.2. Network performance testing is targeted for network performance testing. The network performance testings include underwater channel bit error rate testing, data link layer testing, network layer testing, and application layer testing.3. Protocol for remote software update is considering the disadvantages of the traditional method of software updates, we produce a method which uses the network to remotely update the protocol of the nodes. We can remotely control the ocean test platform to finish the remote testing process and can acquire the test data for analysis or even re-start test.4. Mobile network performance tests can achieve test for mobile networks. The tests include a single-hop test, and the reliability of transmission test.5. Test platform deployment part describes the deployment of an experimental platform, which mainly includes the database design, remote access and display design.The purpose of this paper is to develop a low cost, high reliable test platform for underwater sensor netowrks, and we believe that our work will play an important role for the study of underwater sensor networks.
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