Browsing by Author "Telatar, E."

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Open Access
On the rate of channel polarization
(IEEE, 2009-06-07) Arıkan, Erdal; Telatar, E.
A bound is given on the rate of channel polarization. As a corollary, an earlier bound on the probability of error for polar coding is improved. Specifically, it is shown that, for any binary-input discrete memoryless channel W with symmetric capacity I(W) and any rate R < I(W), the polar-coding blockerror probability under successive cancellation decoding satisfies Pe(N;R) ≥ 2-Nβ for any β > 1/2 when the block-length N is large enough. © 2009 IEEE.
Open Access
Polarization for arbitrary discrete memoryless channels
(IEEE, 2009) Şaşoǧlu, E.; Telatar, E.; Arıkan, Erdal
Channel polarization, originally proposed for binary-input channels, is generalized to arbitrary discrete memoryless channels. Specifically, it is shown that when the input alphabet size is a prime number, a similar construction to that for the binary case leads to polarization. This method can be extended to channels of composite input alphabet sizes by decomposing such channels into a set of channels with prime input alphabet sizes. It is also shown that all discrete memoryless channels can be polarized by randomized constructions. The introduction of randomness does not change the order of complexity of polar code construction, encoding, and decoding. A previous result on the error probability behavior of polar codes is also extended to the case of arbitrary discrete memoryless channels. The generalization of polarization to channels with arbitrary finite input alphabet sizes leads to polar-coding methods for approaching the true (as opposed to symmetric) channel capacity of arbitrary channels with discrete or continuous input alphabets.
Open Access
Reflection coefficient null of acoustic waves at a liquid–anisotropic‐solid interface
(Acoustical Society of America, 1989-01) Ankan, O.; Telatar, E.; Atalar, Abdullah
he reflection coefficient of acoustic waves incident on a liquid–solid interface from the liquid side is numerically calculated for a general anisotropic solid oriented in any arbitrary direction. The reflection coefficient depends, in general, on polar and azimuthal angles of incidence. Results are presented for various crystalline materials of different symmetry classes. A null in the reflection coefficient amplitude is detected at a particular incidence angle for every anisotropic material that supports pseudosurface waves. The null in the reflection corresponds to the excitation of the pseudosurface wave on the interface surface, and it has typically a very narrow angular aperture. The angular position of the null is very critical and highly dependent on the elastic parameters of the anisotropic solid.