Abstract: The presently claimed invention provides a method of channel estimation in a multi-user massive Multiple-Input Multiple-Output system. Candidate pilots are selected for each user equipment based on their spatial correlation matrices. Through determining the similarity of spatial correlation matrices among different user equipments, shared pilots among them can be found, and a base station can transmit a union set of pilots for channel estimation. The present invention is able to provide high channel estimation accuracy and reduce training signal resource.

Abstract: A plug connector being insertable into a corresponding socket connector is provided. The plug connector includes a first housing, a lock, and a first insertion device. The first housing includes a plurality of first connection terminal receiving passageways, while the lock is integrally connected with the first housing. The first insertion device formed on the lock.

Abstract: An integrated optical device and a method of fabricating the integrated optical device comprising at least one waveguide structure is provided. The waveguide structure is fabricated from a dielectric material selected from either (a) a dielectric matrix having quantum dots dispersed therein or (b) an electro-optical polymer. The fabrication method of the present invention incorporates the technique of nano-imprinting (or nano-embossing) a film of dielectric material to define the shape of the waveguide structure. The integrated optical device is operable as one of the following: a wavelength converter, a modulator, a switch, a router, a wavelength filter and a dispersion compensator.