title: Free-space optical channel estimation for physical layer security.
abstract: We present experimental data on message transmission in a free-space optical (FSO) link at an eye-safe wavelength, using a testbed consisting of one sender and two receiver terminals, where the latter two are a legitimate receiver and an eavesdropper. The testbed allows us to emulate a typical scenario of physical-layer (PHY) security such as satellite-to-ground laser communications. We estimate information-theoretic metrics including secrecy rate, secrecy outage probability, and expected code lengths for given secrecy criteria based on observed channel statistics. We then discuss operation principles of secure message transmission under realistic fading conditions, and provide a guideline on a multi-layer security architecture by combining PHY security and upper-layer (algorithmic) security.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Endo
authors.forename: Mikio
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kitamura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ito
authors.forename: Morio
authors.initials: M
authors.lastname: Toyoshima
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Takayama
authors.forename: Hideki
authors.initials: H
authors.lastname: Takenaka
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Shimizu
authors.forename: Nicola
authors.initials: N
authors.lastname: Laurenti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vallone
authors.forename: Paolo
authors.initials: P
authors.lastname: Villoresi
authors.forename: Takao
authors.initials: T
authors.lastname: Aoki
authors.forename: Masahide
authors.initials: M
authors.lastname: Sasaki