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The feedback capacity of the stationary Gaussian additive noise channel has been open, except for the case where the noise is white. Here we obtain the closed-form feedback capacity of the first-order moving average additive Gaussian noise channel. Specifically, the channel is given by Yi = Xi + Zi, i = 1,2,..., where the input {Xi} satisfies average power constraint and the noise {Zi} is a first-order...
In this paper, we study the effect of memory order on the capacity of finite-state Markov channels (FSMC). We analytically compare the capacity of an originally high-order FSMC model with the capacity of its reduced memory order version. We show that the capacity difference is caused by two factors: 1) the channel entropy difference, and 2) the channel observability difference between the two models...
The cutoff rate R0(W) of a discrete memoryless channel (DMC) W is often used as a figure of merit, alongside the channel capacity C(W). Given a channel W consisting of two possibly correlated subchannels W1, W2, the capacity function always satisfies C(W1) + C(W2) les C(W), while there are examples for which R0(W1) + R0(W 2) > R0(W). This fact that the cutoff rate can be "created" by...
We consider the broadcast-relay channel: a broadcast channel where receivers are permitted to assist in the distribution of data to other receivers by relaying. We extend the previous results and demonstrate that effective transmission strategies can be derived by combining well-known techniques for broadcast and relay channels. Additionally, we derive new outer bounds to capacity regions
A relay-without-delay channel in which each transmitted relay symbol can depend on all its past as well as present received symbols is investigated. A general upper bound on the capacity of the channel is established. A lower bound on the capacity for the additive white Gaussian noise relay-without-delay channel is introduced and is shown to coincide with the upper bound for a certain range of parameter...
A new simulation-based method to evaluate the information rates of multidimensional front-ends applied to digital storage channels with transition noise is presented. First, we propose an algorithm which extends recent work on the information rates of magnetic recording channels affected by colored Gaussian thermal noise, intersymbol interference and signal-dependent transition noise, by using linear...
An ensemble of LDPC convolutional codes with parity-check matrices composed of permutation matrices is considered. The convergence of the iterative belief propagation based decoder for terminated convolutional codes in the ensemble is analyzed for binary-input output-symmetric memoryless channels using density evolution techniques. We observe that the structured irregularity in the Tanner graph of...
We consider communication over a time invariant discrete memoryless channel with noiseless and instantaneous feedback. We assume that the communicating parties are not aware of the underlying channel, however they know that it belongs to some specific family of discrete memoryless channels. Recent results (A. Tchamkerten and I.E. Telatar) show that for certain families (e.g., binary symmetric channels...
We introduce a preorder on the line-of-sight (LOS) matrices in coherent multiple-input multiple-output (MIMO) Rician fading channels. We demonstrate that under this preorder, the information rate and the rate-R outage probability corresponding to zero-mean multivariate circularly symmetric Gaussian inputs of arbitrary but fixed covariance matrices are monotonic in the LOS matrix. This result extends...
We investigate the use of capacity and near-capacity achieving LDPC codes on the wire tap channel, where the dual conditions of reliable communications and security are required. We show that good codes for conventional channels (like BSC and BEC) also have interesting and useful security properties. In this paper we show the connection between the decoding threshold of the code and its security against...
We consider both channel coding and source coding, with perfect past feedback/feedforward, in the presence of side information. It is first observed that feedback does not increase the capacity of the Gelfand-Pinsker channel, nor does feedforward improve the achievable rate-distortion performance in the Wyner-Ziv problem. We then focus on the Gaussian case showing that, as in the absence of side information,...
Following the pioneering work of Zheng and Tse, this paper derives the diversity and spatial multiplexing gain tradeoff for MIMO systems employing a multiple beamforming scheme. This result is obtained looking at the channel performance limits when both the SNR and the transmission rate tend to infinity, such that the relation between the rate and the capacity is constant. Assuming a uniform power...
We evaluate the symmetric capacity of the OCDMA/OCDMA (O/O) signature sets that maximize the sum capacity in quasi-scalable CDMA systems. It is found that the symmetric capacity is equal to the sum capacity for randomly scrambled O/O
We present a family of space-time codes for the noncoherent MIMO channel. The codes are constructed via functions that can be considered as a generalization of boolean functions to commuting projection operators which arise in the theory of quantum stabilizer codes. These space-time codes are strongly related to standard binary Reed-Muller codes. In particular, they can be decoded by adapting a decoding...
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