Research On The Synchronization For Ultra-wideband Communication In Body Area Network Employing Nonlinear Signal Processing Technology

The rapid growth in wireless communication,physiological sensors and low-power integrated circuits has enabled a new generation of human-centered wireless sensor networks,which attracts more and more attention and has been gradually used in many fields such as medical monitoring,consumer electronics,military,aviation and so on.For these applications,the IEEE 802.15 TG6 task group proposed the concept of "Wireless body area network(WBAN)" and has developed a new standard for the WBAN aimed at short-range,low power and highly reliable wireless communication,named IEEE 802.15.6.In the IEEE 802.15.6 standard,the Impulse Radio Ultra-wideband(IR-UWB)technology has been adopted as the implementation scheme for the physical layer(PHY)due to its low complexity and low power consumption.Accordingly,the IR-UWB based WBAN has been extensively investigated,and the synchronization for the IR-UWB based WBAN receiver been one of the most active research problems.In this dissertation,we focus on the research of synchronization for IR-UWB receivers applied to the IEEE 802.15.6 WBAN standard and commit to design synchronization schemes with low-complexity and narrowband interference mitigation.The main contributions of our work are as follows.Firstly,the simulation modeling for UWB-based WBAN communication system is set up by analyzing the IEEE 802.15.6 standard.Based on the parameters definition of UWB signal in PHY,such as frame format,modulation,pulse waveform,the model of IR-UWB transceiver based on energy detection for WBAN was built.Secondly,according to the particular structure of the specified synchronization head in the IEEE 802.15.6 standard,a novel energy correlation based synchronization technique for ED receiver with the OOK modulation targeting IEEE 802.15.6 WBAN is presented.The receiver correlates the samples of accumulated energy of received signal and a locally generated template signal.If the correlation peaks appear in the same interval for several times,the coarse timing acquisition is accomplished.During fining timing acquisition,we perform a modified "jump back and search forward(JBSF)" algorithm.Simulation results show that the performance of this method is related with length of template and accord with the time-based-threshold method.The hardware complexity is efficiently reduced.Finally,a new robust synchronization method based on the nonlinear TKO and SL technology is proposed for mitigating the NBI.In the proposed architecture,additional preprocessing blocks which enable to suppress NBI are added to the conventional ED receiver.The additional preprocessing blocks are the combination of the Teager-Kaiser energy operator and a high-pass filter or the Square-law device and a band-pass filter respectively.Based on the simulation results,it is discovered that the nonlinear technologies not only can mitigate destructive effects of NBI but also can improve synchronization success rate performance of energy detection based impulse radio UWB transceivers when no narrowband interference presents.