| China has a vast territory.For the total amount of fresh water,it ranks the fourth in the world,but the distribution is uneven.The water amount occupied per capita in China is only 1/4 of the world average level.Therefore,enhanced monitoring of water resources has a profound impact on national production.At present,the wireless sensor network has gradually become the mainstream method for water resource monitoring.The most commonly used method is water surface monitoring technology,and it has matured day by day.But this monitoring method can only collect the data near the water surface,which has some limitations.In order to monitor the date related to ecology,topography,earth crust and so on in the underwater environment,the underwater wireless sensor network has become the research hotspot.The underwater wireless sensor network collects data from the underwater environment and transfers the data to the base station on the water surface,and the data collected by the base station is then sent to the monitoring center for processing.Underwater is a three-dimensional dynamic environment.The influence of water flow,wave,vortex and other factors will give rise to the difficulty of underwater data transmission.At present,the underwater sound transmission method is the most recognized for the underwater transmission.Acoustic channel transmission is characterized by low bandwidth,short transmission distance,and no way to receive the data when the terminal node is far from the collecting node.It has high bit error rate,and the phenomenon of not receiving signals often occurs.For example,the ship,which is the mobile target,may block the communication between the two parts of the network;the propagation delay is longer than the water surface wireless channel;and the noise underwater will also affect the throughput of the communication channel.Therefore,the underwater wireless sensor network adopts the data collection of multi-hop routing,and the routing algorithm and node deployment for the underwater sensor network must be reconsidered.In China,the research on underwater wireless sensor networks is still in its infancy,and there are many technical difficulties to overcome.In order to realize underwater wireless networking,this article researches the key technologies of underwater wireless sensor network,and focuses on the in-depth theoretical analysis and research for the routing algorithm,the coverage algorithm,the underwater acoustic modem and so on.The specific work is as follows:?1?In view of the high error rate of underwater wireless sensor network,a new algorithm based on water sound channel is proposed to avoid the invalid routing,so as to increase the throughput and reliability in the sparse and lossy underwater environment,and the opportunistic routing only depends on the information provided by the neighbor node of one hop.Each transmission node selects the transmission group and uses distributed beacon mechanism to initiate information from the Sink node.In order to improve the efficiency of underwater communication and avoid the void area,the location awareness routing algorithm based on autonomous underwater glider is proposed.This algorithm includes the location awareness mobile mode and synergic location perception model.The autonomous underwater glider can stay at the set place in the predetermined time,estimate the autonomous confidence of energy consumption and adjacent confidence regions,and then adjusts the launching power of the autonomous underwater glider according to the confidence region.?2?For the unpredictability of underwater mobile nodes,an autonomous underwater glider location algorithm based on mobility prediction is proposed.The autonomous underwater glider equipped with global positioning system is deployed and used as the reference node.These reference nodes are used to locate all non-localized common sensor nodes,so as to reduce the location error and increase the coverage rate,and the maximum ratio combination is used as a diversity technique and combine the source node and the relay node signal from the destination to improve the network throughput.In view of the high energy consumption caused by water,wave,vortex and other factors,the improved K coverage degree sensor network deployment algorithm based on probabilistic perception is proposed,and the maximum weight matching to realize the centralized allocation strategy is introduced to reduce energy consumption in the process of network node movement,thus achieving a better energy saving effect.?3?In view of the serious influence of the changeable underwater environment on the synchronization of underwater glider,the multi-hop underwater wireless sensor network with the intermittent connection of the weinuo region is proposed.The proposed algorithm uses the agent node to locally share the state information of the underwater autonomous glider,so as to omit the requirements for global transmitting of this information to maintain the data forwarding routing and reduce data collection latency in large-scale hierarchical type of underwater wireless sensor network.?4?In order to realize the conversion between sound signals and electrical signals,a high speed and low power Underwater acoustic modem based on field-programmable gate array is designed.The performance of full duplex point-to-point communication of this modem is validated with a 1MHz signal carrier and On-Off Keying?OOK?modulation.The results indicate that this modem achieve1Mbps data-rate and.3 2×103-Bit Error Rate?BER?with 160uW/bit power consumption.The data-rate is improved significant while ensure the communication quality.Design of water resources monitoring system based on wireless sensor network.The system adopts the three-dimensional monitoring means.Underwater sound wireless sensor network is used to collect water environment parameters.After the modem which converges the node converting the data into the water surface transmission signal,use the General Packet Radio Service?GPRS?module of water surface gateway to upload the data from the entire network monitoring points to the remote monitoring processor,and achieve the purpose of remote monitoring of water resources. |
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