UWB Pulse Design Based On Electromagnetic Spectrum Engineering

Ultra-wideband (UWB) technique is considered as a revolutionary breakthrough of wireless communication. It has high transmission rate, low power consumption and anti-multipath and so on, which makes that it has been applied in military affairs and civil fields. Radio communication management complies with two rules: new wireless technique can not bring baleful interference to known wireless systems, and the interfered system can bear all interferences from radios. Taking up very wide frequency bandwidth, UWB system interferes with other narrow communication systems each other. The main method to make them compatible is design pulse for UWB system to satisfy the emission mask that Federal Communication Committee (FCC) constituted. This paper will optimize combinational Gaussian pulses with genetic algorithm (GA).Modern frequency spectrum resource of wireless communication systems is confirmed by radio management organization in static manner that makes frequency spectrum scarce. FCC pointed out that the root is not short of frequency spectrum, but the actual frequency distributing manner made low utilization rate of frequency. Cognitive radio (CR) is an intelligent dynamic frequency distributing method, it can sense frequency spectrum and enhance utilization rate of frequency, and improve frequency share. So introduced CR into UWB, that was called CUWB, and designed pulse for CUWB system. The main contents and contributions of this dissertation are as follows:1. considering different order Gaussian derivatives as functions, combined them into a new pulse, and optimized its pulse shaping vector, weight vector, pulse shaping vector and weight vector. Combined with single Gaussian derivative pulse, the optimized pulse can take much more energy, and approach to FCC emission mask further.2. Approximate prolate spheroidal wave functions (APSWF) were used to design pulse for CUWB system. APSWF was finite in tome domain and frequency domain. If APSWF pulse got across an ideal band-pass filter, it would be modulated to arbitrary frequency. Firstly CR apperceived free band and being occupied frequency by other narrow band communication systems, secondly partitioned the free band into several sub-band, thirdly chose proper time width and bandwidth of APSWF pulse, then ascertained the low frequency and high frequency of ideal band-pass filter, finally added the modulated pulses to attain expected pulse. The pulse frequency spectrum had a flute in narrow band frequency, the depth of the flute can be adjusted by changing time width and bandwidth of APSWF pulse.