Conference Paper

The multiple coding gain with two criteria in an attenuated quantum channel

Postgrad. Course in Sci. & Technol., Meijo Univ., Nagoya
DOI: 10.1109/ISITA.2008.4895459 Conference: Information Theory and Its Applications, 2008. ISITA 2008. International Symposium on
Source: IEEE Xplore


Recently, the capacity of an attenuated quantum channel which is a model of a long distance optical fiber channel was derived. This capacity is in principle achieved by a continuous modulation and a random coding. However, a continuous modulation and a random coding are not practical. Therefore, we need discussion about capacity used for more practical modulation and coding. In this paper, we show characteristics of both information and error probability criteria for an attenuated channel using M-ary PSK modulation and pseudo-cyclic codes.

Full-text preview

Available from:
  • Source
    • "In the previous work, we showed that the narrowband channel capacity is achieved by digital modulations [3]. We have also studied encoding and decoding to approach the capacity [4], [5], [6]. In present paper, as a method to approach the ultimate limit, we study to approach the broadband channel capacity using the wavelength division multiplexing. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Recently, the exact solution of the capacity of an attenuated quantum channel which is a model of a long distance optical fiber channel was derived [V. Giovannetti, et al., Phys. Rev. Lett. 90, 027902, (2004)]. In particular, the capacity of a broadband quantum channel, which is the ultimate limit of quantum communications, was shown. In this paper, we consider wavelength division multiplexing in order to attain the capacity of a broadband quantum channel.
    Preview · Conference Paper · Nov 2010
  • [Show abstract] [Hide abstract]
    ABSTRACT: A formula of channel matrix for linear codes over Zm is presented. m-ary PSK coherent-states are used as letter states and the square-root measurement (SRM) is used as a decoding. First, arbitrary linear codes over Zm are shown to group covariant. Then the formula of channel matrix is derived by generalizing [T.S. Usuda, S. Usami, I. Takumi, and M. Hata, Phys. Lett. A305, pp.125-134, (2002)]. Furthermore, the usefulness of the formula is considered.
    No preview · Conference Paper · Oct 2010
  • [Show abstract] [Hide abstract]
    ABSTRACT: In 2004, Giovannetti and others gave both the broadband and narrowband channel capacities of an attenuated quantum channel [1]. However, the derived broadband channel capacity is impossible to realize. Therefore, we treat the broadband channel capacity as an upper bound and it is necessary to derive an achievable limit. In a previous work, to show the true capacity, the capacity by wavelength division multiplexing (WDM) was defined and compared with the broadband channel capacity when there is no attenuation [7]. We consider more detailed properties of this WDM capacity and attenuated channels with frequency-dependent loss.
    No preview · Conference Paper · Jan 2012