We provide a counterexample to Cover’s conjecture that the feedback capacity CFB of an additive Gaussian noise channel under power constraint P be no greater than the nonfeedback capacity C of the same channel under power constraint 2P , i.e., CFB(P ) C(2P ). Index Terms|Additive Gaussian noise channels, channel capacity, conjecture, counterexample, feedback.

Miriam H. Huntley1,∗, Arvind Murugan1,2,∗ and Michael P. Brenner Harvard John A. Paulson School of Engineering and Applied Sciences and the Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, Massachusetts 02138, USA 2 Physics and the James Franck Institute, University of Chicago, Chicago, IL 60637 and Department of Physics, Harvard University, 17 Oxford St. Cambr...

Arıkan’s polar coding, is by now a well studied technique that allows achieving the symmetric capacity of binary input memoryless channels with low complexity encoding and decoding, provided that the polar decoding architecture is used and the decoding metric is matched to the true channel. In this paper, we analyze communication rates that are achievable when the polar coding/decoding architec...

In this chapter we provide a brief introduction to multidimensional codes. In particular, we focus on product codes and other similar codes that use parity checks over multidimensional arrays. We present a brief introduction to product codes and their properties. We then focus on multidimensional codes based on single parity-check constituent codes. We provide two applications that illustrate t...

vi

Abstract—In this paper, the concept of composibility of the total channel capacity of the system of channels composed of two independent subsystems of channel is discussed. This system of channels is a function of entropies of the subsystems. Here, we show that the generalized entropies, the Tsalli’s entropy, the normalized Tsalli’s entropy and the Kapur’s entropy are compatible with the compos...

this paper proposes a new smart antenna beamforming scheme based on electronically steerable parasitic array radiator (espar). the proposed method is capable of providing better capacity compared to the conventional espar. the termination of each antenna element in this structure comprises a pin diode in addition to a varactor. using pin diode besides the varactor provides more degrees of freed...

The subject of this paper is to analyse the low voltage distribution lines inside the consumer premises, in order to attain a channel model useful to simulate its behaviour for high bit-rate digital communications. Measurements have also been performed both in the laboratory and in residential buildings, and results are presented and discussed. Finally, some estimations of the channel capacity ...

This paper is a tutorial review on important issues related to code-division multiple-access (CDMA) systems such as channel capacity, power control, and optimum codes; specifically, we consider optimum overloaded codes that achieve errorless transmission in the absence of noise for the binary and nonbinary cases. A survey of lower and upper bounds for the sum channel capacity of such systems is...

— This paper discusses the characteristics of a space-to-space multiple-input, multiple-output (MIMO) communication channel that distinguish it from more common terrestrial MIMO communication channels. These characteristics imply that the channel matrices for space communication channels have a particularly simple structure that leads to statistical characteristics that are both predictable and...