Research On Residual Energy’s Usage Time Of Wireless Sensor Network Nodes

Wireless sensor networks(WSN) has been widely used in many fields, and become a part of daily life due to its distributed environment perception and the simple and flexible deployment of wireless communication technology.WSN consists of tiny sensor nodes, which has functions of acquiring information and the network relay. When transmit and process information, the sensor nodes must consume energy, even if the sensor node is stationary, its limited power supply source will change. The energy consumption and service time of nodes have great impact on the performance and availablity of WSN. Therefore, research on residual energy’s usage time calculation has become one of the most important topic of WSN field.In this thesis, problems related to the energy consumption and the usage time of WSN nodes were introduced, and the WSN’s energy consumption characteristics, models and theories are analyzed, its validity and practicality are proved by practical test and simulation. Main work is as follows:(1) WSN’s architecture, composition, characteristics, influence factors of nodes’ energy consumption and key technology of consumption on communication module are analyzed. A more overall energy consumption model is given, which includes a wireless transceiver model, electromagnetic radiation model, electronic circuits model, state transition model, retransmission statistics model and start energy model.(2) Based on the energy consumption model, the calculation method of residual energy usage time is given, and the validity of model and the calculation are verified by real experiment and simulation. Calibration experiment of power supply for WSN nodes and measurement of energy consumption for each working state are completed by building the energy consumption tests platform, and the energy for transmitting a bit without error consumption is calculated, then the residual energy usage time is calculated;the validity and reliability of algorithm was tested by configuring the different state and adding RM battery model to NS-2, then the simulation of energy consumption statistics and usage time of nodes on different scenarios are completed, and finally the calculation results was verified by comparison with experimental data.(3) Considering the energy consumption in complex scenarios of WSN nodes, this thesis analyzed the impact of retransmission mechanism on energy consumption in-depth.The main work focus on the differences of simple hybrid automatic repeat request(S-HARQ) and hybrid automatic repeat request chase combining(HARQ-CC) under fast fading and block fading channel, deriving the and expressions for the expected number of transmission trials. And the optimization scheme is proposed for the selection of bit rate and retransmission mechanism.