Research On Data Transmission In Wireless Body Area Networks Based On Network Coding

Interest in Wireless Body Area Networks (WBANs) has increased significantly in recent years thanks to the advances in microelectronics and wireless communications. While general wireless sensor networks is almost a class of data-centric networks, WBANs is a human-centric network. Its network data, which is critical for the user and medical personnel, is of extreme sensitivity. That is, data transmission is one of its key processes and to design suitable data transmission strategies, by which the sensed data could transmit to the personal service effectively, is an important challenge for the practical deployment. In this thesis, the research object we takes is a WBANs with several wearable inertial sensors. The data transmission strategy, as the main concern of this thesis, is studied via the network coding, cooperative communication and elliptic curve cryptography from 3 different aspects, which contain reliable, secure and energy-efficient. The main contributions of the thesis are summarized below:1. Sensor cooperation techniques using network coding for transmitting physiological data from WBANs sensors to the personal service to achieve reliable data transmission have been proposed. For traditional point-to-point WBANs communication systems, sensors data is sent directly to the personal service. In the direct transmission, those sensors’signals are affected by fading because of reflection, diffraction, energy absorption, shadowing by body, etc. To combat fading effect effectively, this paper attempts to introduce energy efficient network coding into novel traditional multi sensor cooperation. Each sensor node will send both their own monitoring data and other sensor monitoring data to the personal service, and spatial diversity is achieved across two sensors via sensor cooperation. We analyze the outage performance of three transmission strategies that could be implemented in WBANs, i.e., direct transmission, traditional cooperation, and network coding-based sensor cooperation. Our simulation results indicate that:cooperative communication strategy based on network coding in WBANs channel provides superior performance compared to other two strategies.2. A secure data transmission strategy in WBANs based on network coding and elliptic curve cryptography algorithm is proposed. Security challenges in WBANs have been paid unprecedented attention for the vulnerable of patient’s personal sensitive data in recent years. In order to address prevalent security concerns, this paper attempts to design a security data transmission strategy. The strategy firstly introduces network coding to establish a multicast model in WBANs. The energy efficiency of the network increases as more volume of data will be transmitted to the sink with same number of transmissions. Signing the packets by utilizing elliptic curve cryptography (ECC) algorithm, secure communication of patient-related physiological data is possible in hostile environments. The proposed strategy divides into three phases i.e., setup, signature and verification. Data simulation proves that the strategy is secure. It simultaneously prevent pollution attacks and detects malicious nodes that intentionally corrupt content in the network. Based on all of this information, the proposed strategy can provides a well-designed network topology.3. An energy-efficient data transmission strategy for WBANs that utilizes multi-hop strategy to forward packets to the personal service is presented. Keeping low energy consumption by each sensor node during the data transmission process is of extreme significance in wireless body area networks. In case of single-hop communication, nodes which are at greater distance from the sink will die faster because of more energy utilization, whereas, multi-hop communication causes increase in the energy consumption of forwarder nodes which are closer to the sink. Therefore, this paper presents an energy-efficient strategy that maximizes the network lifetime and stability period by using the merits of both multi-hop and single-hop communication. It selects a forwarder node with the lowest cost function based on remaining energy and distance to the personal service for minimum energy consumption. Besides, the strategy includes a decision rule that ensures delivery of important packets during low energy conditions. Simulation results show that the proposed strategy performs better than other transmission strategies in terms of network lifetime, network stability, average residual energy and total number of packets transmitted in success. Comparing with the direct data transmission strategy and the transmission priority decision scheme, the proposed strategy prolongs the network lifetime about 50% and 10%.