Improved Lower Bounds on Mutual Information Accounting for Nonlinear Signal--Noise Interaction

• In fiber-optic communications, evaluation of mutual information (MI) is still an open issue due to the unavailability of an exact and mathematically tractable channel model. Traditionally, lower bounds on MI are computed by approximating the (original) channel with an auxiliary forward channel. In this paper, lower bounds are computed using an auxiliary backward channel, which has not been previously considered in the context of fiber-optic communications. Distributions obtained through two variations of the stochastic digital backpropagation (SDBP) algorithm are used as auxiliary backward channels and these bounds are compared with bounds obtained through the conventional digital backpropagation (DBP). Through simulations, higher information rates were achieved with SDBP, which can be explained by the ability of SDBP to account for nonlinear signal--noise interactions

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Kommunikationssystem (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Communication Systems (hsv//eng)

Keyword

Achievable information rate

auxiliary channel

fiber-optical communications

mismatched decoding

nonlinear compensation

stochastic digital backpropagation

Backpropagation algorithms

Fiber optics

Nonlinear optics

Signal noise measurement

Stochastic systems

Digital backpropagation

Fiber optical communications

Non-linear compensations

Optical fiber communication

Publication and Content Type

ref (subject category)

art (subject category)