Study On The Wireless Multimedia Sensor Networks For Underground Coal Mine Based On MB-OFDM-UWB

For the question of the increasingly complicated monitoring environment in the underground coal mine,the serious multipath fading of underground wireless channel and the limited energy of the sensor nodes,in order to ensure the safety of smooth production in coal mine,it is necessary to obtain more comprehensive and accurate information of underground environmental monitoring.In this paper,the wireless multimedia sensor transmission technique in the coal mine has been build based on MB-OFDM-UWB and some key technologies have been studied.The main research contents and achievements are as follows:(1)For the characteristics of banded confined space in coal mine tunnel and the demand of multimedia information gathering,a heterogeneous wireless multimedia sensor network system in the coal mine has been build based on MB-OFDM-UWB,the network topology and working mode have been designed so that the network can work effectively.(2)For the problem of the serious multipath fading of the wireless channel in narrow confined space,the channel condition of the nodes in some locations to the base station are poor,the MB-OFDM-UWB time-frequency coding cooperative transmission scheme for heterogeneous wireless multimedia sensor networks in the coal mine has been proposed.The scheme has realized the cooperation between the channel condition of the good and the poor nodes.The simulation results show that using the proposed MB-OFDM-UWB time-frequency coding cooperative transmission scheme in coal mine,the bit error rate performance of nodes with poor channel condition in the network has been greatly improved.(3)For the characteristics of long and narrow structure of mine roadway,a PREVG clustering algorithm for heterogeneous wireless multimedia sensor networks based on virtual grid has been proposed.Based on the communication radius of the nodes in the network,nodes have been divided into virtual grid for cluster management,the residual energy and the location information of the nodes have been taken into account in the process of selecting the upper cluster head nodes in this algorithm.The simulation results show that using the proposed PREVG clustering algorithm in the coal mine,the transmission efficiency of data in the network has been effectively improved,the energy consumption of the nodes in the network has been balanced and the life cycle of the network has been prolonged.(4)For the problem of the limited energy of sensor nodes in coal mine,generally far distance between the upper cluster head node and the sink node and the large energy consumption of the transmission to the sink node,combined with PREVG clustering algorithm,an EDACA routing algorithm based on ant colony for heterogeneous wireless multimedia sensor networks in coal mine has been proposed.The alternative cluster head node has been introduced to the upper cluster head,the residual energy and the distance information between the nodes of cluster heads have been taken into account in the routing process from the cluster head node to the sink node in this algorithm.The simulation results show that using the EDACA routing algorithm in the coal mine,the number of energy-exhausted nodes in the coal mine has been reduced,the long-term transmission of data has been guaranteed,the life cycle of the network has been prolonged and the performance of the network monitoring has been improved.The above results show that using the proposed MB-OFDM-UWB time-frequency coding cooperative transmission scheme in the data transmission of common nodes,using the proposed PREVG clustering algorithm in the cluster management of common nodes and using the proposed EDACA routing algorithm in the communication path selection between the cluster head node and the sink node,the reliability of data transmission and energy efficiency of nodes in heterogeneous wireless multimedia sensor networks have been effectively guaranteed.