Broadband Technology Research In Wireless Sensor Networks Transmitted Reference Ultra

Wireless sensor network (WSN) is an important part of the internet of thing, which uses a plenty of static or mobile sensor to constitute a wireless network by self-organization or jump. It perceives, collects, processes and transmits monitoring information of perception object from geographical area of covering network by cooperation, and reports the information to users. Transmitted reference ultra-wideband (TR-UWB) technology is a kind of the incoherent receiver technology of ultra-wideband, whose characteristics of low complexity and power consumption are very suitable for WSN application, etc. The key technology of TR-UWB is studied and the typical WSN application systems are designed in the paper. These following research results are completed:(1) Chaotic signals have broadband properties. Differential chaos shift keying (DCSK) and frequency modulation differential chaos shift keying (FM-DCSK) can be looked as a kind of TR-UWB. Based on the traditional DCSK and FM-DCSK system, the improved methods of these systems are proposed. The influences on the performance of the system parameters are analyzed, and how to choose parameters for balance between performance and complexity is discussed in the paper.(2) The reference and information part is divided as time division, frequency division, and code division in TR-UWB. They have the same decline characteristics through the channel. The performances of three different ways of TR-UWB system are analyzed and compared in the paper, and the uniform TR-UWB model is proposed in the end.(3) The power spectrum of the TR-UWB is very widely, so performance of other wireless systems in same band will be interfered with. The power spectrum characteristics of the time division, frequency division, code division TR-UWB signal are analyzed in the paper, and the concept of cognitive TR-UWB is proposed. The method to eliminate the discrete part of spectrum by randomization the reference part is proposed. The methods to generate notch power spectrum by using a jump code optimization design or delay Gaussian pulse synthesis are proposed. The interference with other wireless system is suppressed by using the notch signal.(4) The hard decisions and soft decisions of the simple transmitted reference (STR) and averaged transmitted reference (ATR) receiver are analyzed and compared to improve the receiving performance of TR-UWB. A suboptimal receiver of CM-TR-UWB is proposed which use method like ATR receiver. The method of optimal energy distribution between reference and information part is discussed. The method of using notch pulse of transmitter and notch filter of receiver to eliminate narrow band interference is proposed.(5) The design method of the bedroom environment monitoring WSN system, the health monitor WSN system based on Zigbee, and the positioning audio and video terminal based on the DM642DSP are discussed in the end.