公开(公告)号：US20180323904A1

公开(公告)日：2018-11-08

申请号：US15773035

申请日：2016-11-01

Applicant: NEC CORPORATION

Inventor： Kohei HOSOKAWA ,  Toshiharu ITO ,  Manabu ARIKAWA ,  Seigo TAKAHASHI ,  Takashi ISHIKAWA ,  Yoshimasa ONO

IPC: H04L1/00 ,  H04L27/22 ,  H04B10/61 ,  H04B10/118 ,  H04L27/00

CPC classification number: H04L1/0057 ,  H04B10/118 ,  H04B10/61 ,  H04L27/0014 ,  H04L27/22 ,  H04L2027/0057

Abstract: An appropriate synthesized signal cannot be obtained by only correcting relative phase errors of a plurality of received signals; therefore, a received signal processor according to an exemplary aspect of the present invention includes a plurality of signal-to-noise ratio estimation means for estimating respective signal-to-noise ratios of a plurality of digital signal sequences in which relative phase errors of a plurality of received signal sequences having been corrected; a plurality of temporary decision means for performing symbol decisions of the plurality of digital signal sequences and outputting symbol signal sequences; symbol-map-rotation determination means for determining respective phase rotation amounts of the plurality of digital signal sequences from the plurality of symbol signal sequences and the respective signal-to-noise ratios of the plurality of digital signal sequences; and a plurality of phase rotation means for rotating phases of the plurality of digital signal sequences respectively based on the phase rotation amounts.

公开(公告)号：US20200304213A1

公开(公告)日：2020-09-24

申请号：US16088328

申请日：2017-03-17

Applicant: NEC Corporation

Inventor： Kohei HOSOKAWA ,  Toshiharu ITO ,  Seigo TAKAHASHI ,  Manabu ARIKAWA ,  Takashi ISHIKAWA ,  Yoshimasa ONO

IPC: H04B10/69 ,  H04B10/11 ,  H04B17/336

Abstract: The objective of the present invention is to reduce the size of a receiving device circuit in an optical space communication system while maintaining communication stability. A data receiving device which decodes one item of data from a plurality of input signals includes: two or more digital signal processing means for subjecting the plurality of input signals to signal processing; a first recording means for temporarily recording the plurality of input signals; a SN ratio estimating means for estimating S/N ratios of each of the plurality of input signals and determining the number of the plurality of input signals to be combined, and the signals to be combined; and a scheduling means for carrying out overall control on the basis of the results from the SN ratio estimating means.

公开(公告)号：US20180234180A1

公开(公告)日：2018-08-16

申请号：US15751369

申请日：2016-08-17

Applicant: NEC CORPORATION

Inventor： Seigo TAKAHASHI ,  Toshiharu ITO ,  Kohei HOSOKAWA ,  Manabu ARIKAWA ,  Yoshimasa ONO ,  Takashi ISHIKAWA

IPC: H04B10/116 ,  H04B10/50 ,  H04B10/61

CPC classification number: H04B10/116 ,  H04B10/1121 ,  H04B10/118 ,  H04B10/50 ,  H04B10/61

Abstract: It is difficult in a free space optical transmitter to transmit a beacon beam stably at low cost, and that it is impossible to maintain stable tracking; therefore, a free space optical transmitter according to an exemplary aspect of the present invention includes a laser beam transmitting means for transmitting a plurality of laser beams capable of interfering with each other and differing in one of an optical frequency and a time variation in a phase difference; and a wavefront control beam transmitting means for transmitting, to a free space, a plurality of wavefront control beams obtained by making each of the plurality of laser beams have a different wavefront.