Stairs Sequence based Analog to Information Conversion for spectrum sensing of multiband signals

A stairs-shaped sequence (Stairs sequence) is proposed as mixing sequence at the front end of modulated wideband converter (MWC) frame. Modulated Wideband Converter (MWC) system, which is based on the emerging theory of Compressed Sensing (CS), can sample multiband signals at a sub-Nyquist rate without carrier frequencies as a precondition. Frequency mixing of input signals with mixing sequence is the first step of MWC system. In the traditional structure, mixing sequences are random alternating sequences with values of +1 or -1, Stairs sequence is the result of the study on the randomness of the mixing sequence. The main part of the sequences have the value of 1, and the rest are short sequences with the value of -1, which form a similar shape of stairs between the channels. Compared with the traditional random alternating sequence, the new sequence greatly reduces the switching frequency and times of between +1 and -1 in a single cycle, and is more stable for white noise. Simulation results show that the reconstruction performance of Stairs sequences is better than that of random sequences in the face of white noise.