| BSN(Body Sensor Network) is composed of a number of sensor nodes placed in human body, on body surface or around body, which can collect real-time human physiological data and carry on the analysis computation and transmission. In some scenes, such as medical care, sports area, etc., the sensor nodes of each user form a BSN, while multiple users form a bigger BSN. In order to make the communication between each node in BSN effectively, the channel assignment protocol should be studied, which mainly concerns the communication efficiency, the fairness of communication, and the power control problem. In addition, gesture recognition technology has been widely used in medical and sports areas, while the development of Micro-Electro-Mechanical system has improved the accuracy of gesture recognition based on BSN, as well as reduced the requirements to environment. Taking BSN as research objects, this dissertation studies on the protocol of channel assignment, involving the efficiency problem, the fairness problem, and the power control problem. Besides, the method of gesture recognition based on BSN is designed by using Micro-Electro-Mechanical system. The main work is shown as follows:The efficiency problem of channel assignment of nodes communication in multi-channel environment is studied. A new protocol named DGPCI-DCA (Dynamic Game with Perfect and Complete Information based Dynamic Channel Assignment) is proposed, since game theory is an effective tool to solve problems of distributed resource. When all the nodes are rational and greedy, each node selects channel dynamically by backward induction according to strategies of other nodes, thus to calculate the optimization selection strategy of current node itself. Ultimately, dynamic channel assignment is reached, with improving of network throughput and reduces packet loss rate and transmission delay.The fairness problem of channel acquisition of nodes is investigated in BSN. An adaptive fairness algorithm of channel assignment in BSN is proposed based on channel occupancy rate. The current network correspondence is classified into four types according to the history of correspondence and the relationship between the current channel occupancy rate and the ideal occupancy rate. In each type, the collision window value of node is set dynamically based on the current network load. Experiments show that the algorithm performs well under various load conditions, improving throughput significantly as well as fairness among nodes with no hungry nodes appearing.The power control problem is addressed for nodes to transmit packets in BSN. A power control based MAC layer channel assignment method is proposed, assigning different power values to different channels. Transmit power and corresponding channel are selected according to the distance between communication nodes. Simulation results show that the method can effectively reduce the collision domain range and communication conflict caused by asymmetrical links, and improves network throughput at the same time. Furthermore, it reduces the node energy consumption and heating, which avoid the possible damages to human body.The gesture recognition problem in BSN is discussed with the design of gesture recognition node based on Adaptive Extended Kalman Filter. The angular velocity output of gyroscope is compensated by accelerometer and electronic compass of node by means of iterative calculation, which reduces the system error effectively. Experiments show that the method significantly improves the accuracy of gesture recognition. |
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