The Research Of Error Control Schemes In Wireless Sensor Networks

Wireless sensor networks which are equipped with tiny sensor nodes consisting of sensing, data processing, and communicating components have extended the solo sensor detection to self-organized intelligent detection networks that can be positioned far from the actual phenomenon. Sensor networks represent a significant improvement over traditional sensors and enlarge the application scope and philosophical category of them.Energy constraints are the driving factors in the design of wireless sensor networks, which require low power consumption and energy efficient communication protocols. Moreover, the broadcast nature of the wireless channel and the multi-hop structure of the wireless sensor networks necessitate error control protocols to achieve reliable data transportation. Accordingly, energy efficient error control schemes should be considered in designing of sensor networks. In this thesis, the optimum error control scheme is studied based on energy efficiency analysis. The main results of this thesis are as follows:Firstly, this thesis gives a comprehensive analysis of characteristics and applications of wireless sensor networks and indicates that the necessity and importance of error control schemes in wireless sensor networks. Furthermore, related research works are summarized in the thesis.Secondly, this thesis proves that energy efficiency of ARQ technique is independent of retransmission attempts and is unchangeable with the number of retransmission. Computer simulation is presented to verify the mathematical proof.Thirdly, energy efficiency analysis of FEC is presented in this thesis. Energy efficiency of BCH code outperforms any other channel codes due to its low encoding and decoding energy consumption. The mathematical analysis for energy efficiency of FEC is presented. The result of our analysis reveals that there is an optimum FEC scheme with the largest energy efficiency for a target communication distance and packet size.Fourthly, Chase combining Hybrid ARQ is proposed to achieve adaptive error control. Chase combining HARQ is compared with ARQ and FEC in terms of energy efficiency based on different communication distances and packet lengths. To the best of our knowledge this is the first work which proposes Chase combining HARQ for wireless sensor networks.