Introduction
UWB signals is short for ultra wideband signals, which define as those whose 10dB bandwidth is larger than 500MHz and locate within 3.1-10.6GHz. It gains much attention because of its potential of transmitting large volume of data. The waveform of a UWB signal is under heated discussion. The spectrum of an ideal UWB waveform should be nowhere exceed the FCC spectral mask. However, due to the physical restriction of generating UWB waveforms, some parts of the spectrum no longer follow the mask requirement when the power of the signal is fully used and thus cause interferences for other signals. Therefore, the amount of interferences out of the FCC mask should be carefully measured. These interferences directly give the amount of impact for other signals when the UWB signal’s power gets maximum and also illustrate how good a waveform is if the FCC mask is chosen as a benchmark.
Contents
In the patent ,we give two parameters to describe interferences. The sum of frequency bandwidth for parts out of the FCC mask and the sum of power for parts out of the FCC mask. For instance, the shaded zones in the below figure represents the interferences when the power of the signal reaches maximum.
For any series of UWB pulses, by saying that the power reaches maximum, it means the maximum power density hits the ceiling of the FCC mask. This physically corresponds to the situation of the shortest time interval between two pulses. The area in the linear coordinate represents the power that exceeds the FCC mask. Consider the equity of different frequency components, it’s reasonable to sum power in every exceeding part to describe how much power causes impact to other signals.
Moreover, the sum of bandwidth that exceed the FCC mask is also used to describe the waveform. One situation is that for two waveforms, one has narrower exceeding bandwidth than the other while they have the same amount of exceeding power, which is better? The answer should be the latter one. As wilder exceeding bandwidth signal releases the burden for a specific frequency component when power gets maximum, less power should decrease to satisfy the FCC mask. Considering that power determines the transmission distance, it should be as large as possible without other techniques support.
Patent Current Status and Information
The patent is now open to the public and is waiting for authorization by China National Intellectual Property Administration, and typically this will take one year and a half. However, the contents can be found on WANFANG DATA, one of the largest academic database in China. Below is the link.