Sub-Rayleigh ghost imaging via structured illumination

The structured illumination adopted widely in super-resolution microscopy imaging works for the ghost imaging scheme also. Here, we studied the ghost imaging scheme with sinusoidal-structured speckle illumination, whose spatial resolution can surpass the Rayleigh resolution limit by a factor of 2. In addition, even if the bucket intensity signal originated from the diffraction of the object plane with a certain distance, the improvement of spatial resolution is still effective. Our research shows that the structural illumination method, an independent super-resolution technology, is expected to be grafted with a variety of super-resolution ghost imaging schemes to further improve the resolution of imaging systems, such as the pseudo-inverse ghost imaging.

Low Peak-to-Average Power Ratio FBMC-OQAM System based on Data Mapping and DFT Precoding

Filter bank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) is an alternative to OFDM for enhanced spectrum flexible usage. To reduce the peak-to-average power ratio (PAPR), DFT spreading is usually adopted in OFDM systems. However, in FBMC-OQAM systems, because the OQAM pre-processing splits the spread data into the real and imaginary parts, the DFT spreading can result in only marginal PAPR reduction. This letter proposes a novel map-DFT-spread FBMC-OQAM scheme. In this scheme, the transmitting data symbols are first mapped with a conjugate symmetry rule and then coded by the DFT. According to this method, the OQAM pre-processing can be avoided. Compared with the simple DFT-spread scheme, the proposed scheme achieves a better PAPR reduction. In addition, the effect of the prototype filter on the PAPR is studied via numerical simulation and a trade-off exists between the PAPR and out-of-band performances.