Research On Impulse Generation In UWB Systems

The technology of UWB (Ultra Wide Band) provides a new scheme for people to solve the problem about scarcity of frequency resource. This technology can make a large throughput for its wide band, also, it has powerful noise-resistance and low radiated power. Along with the exploitation of Cognitive Radio, UWB has a new development, CUWB (Cognitive UWB). Comparing the traditional UWB, CUWB makes a considering improvement: it can match a variable emission mask and suppress a narrow band interference in any frequency. Correspondingly, it puts forward higher requirement for performance of UWB impulse.The article emphasized on research and improvement of algorithm of impulse generation based PSWF(Prolate Spheroidal Wave Function). At first, we educed a conclusion that the impulse based PSWF fits CUWB best through simulations, and then, in order to suppress a narrow band interference , we make out two algorithm of impulse generation,"Different steps searching"and"Multi-band impulses composing".After many simulations in different situations, it seems that"Different steps searching"can solve the problem that the notch of spectrum can't be controlled precisely and the result of spectrum suppressing isn't stable in formal algorithm. Not only the notch of spectrum can be controlled precisely, but also the PSD in such notch is as low as -75dBm. Even though the result of spectrum suppressing by"Multi-band impulses composing"is not as good as"Different steps searching","Multi-band impulses composing"can acquire a higher utilization per cent in spectrum.