A coding theorem for the discrete memoryless broadcast channel

A coding theorem for the discrete memoryless broadcast channel is proved for the case where no common message is to he transmitted. The theorem is a generalization of the results of Cover and van der Meulen on this problem. The result is tight for broadcast channels having one deterministic component     

Capacity per unit cost of a discrete memoryless channel

A necessary and sufficient condition for an input probability distribution to achieve the capacity per unit cost of a discrete memoryless channel is derived. This condition can be used to compute the capacity per unit cost as illustrated by examples.<>     

The discrete memoryless multiple-access channel with cribbing encoders

The capacity regions are determined for various communication situations in which one or both encoders for a multiple access channel crib from the other encoder and learn the channel input(s) (to be) emitted by this encoder. Most of the achievability proofs in this paper hinge upon the new concept of backward decoding. Also, the notion of Shannon strategies seems to be of crucial importance. It is demonstrated that in some situations parts of the total cooperation line are achievable. Moreover, it is proved that if the encoders and the decoder are allowed to be nondeterministic, the capacity regions are not increased.     

Accurate computation of the performance of M-ary orthogonal signaling on a discrete memoryless channel

A formula for the error rate of maximum-likelihood detection of M-ary orthogonal signaling on a discrete memoryless channel is manipulated into a form that avoids numerical imprecision when it is used to calculate low error rates.     

Random coding theorems for the general discrete memoryless broadcast channel

Three different communication situations are considered for the general nondegraded discrete memoryless broadcast channel with two components. In the most general situation, common and separate information is sent to both receivers. In another situation, only separate information is sent, and in a third, one Common and one separate message is sent. For each communication situation a random coding inner bound on the capacity region is derived. An example is presented which Shows that in the most general situation the inner bound strictly dominates the family of rates obtained by time-sharing. The capacity region for the general situation is characterized by a limiting expression. The relationship with the degraded broadcast channel and the connection with other multiway channels, such as the channel with two senders and two receivers, is shown.     

Information rates achievable with algebraic codes on quantum discrete memoryless channels

The highest information rate at which quantum error-correction schemes work reliably on a channel is called the quantum capacity. Here this is proven to be lower-bounded by the limit of coherent information maximized over the set of input density operators which are proportional to the projections onto the code spaces of symplectic stabilizer codes. The quantum channels to be considered are those subject to independent errors and modeled as tensor products of copies of a completely positive linear map on a Hilbert space of finite dimension. The codes that are proven to have the desired performance are symplectic stabilizer codes. On the depolarizing channel, the bound proven here is actually the highest possible rate at which symplectic stabilizer codes work reliably     

A proof of Marton's coding theorem for the discrete memoryless broadcast channel (Corresp.)

A simple proof using random partitions and typicality is given for Marton's coding theorem for broadcast channels.     

Partial feedback for the discrete memoryless multiple access channel (Corresp.)

The region Cover and Leung found for the discrete memoryless multiple access channel with feedback to both encoders is proved achievable also with feedback to only one encoder. The novel ideas of nonrandom partitions and restricted decoding are used to avoid list coding techniques.     

A low-rate improvement on the Elias bound (Corresp.)

An upper bound on the minimum distance of binary blocks codes, which is superior to Elias' bound forR < 0.0509^+, is obtained. The new hound has the same derivative(-infty)atR = 0as Gilbert's lower bound. (Elias' bound has derivative-ln 2atR = 0).     

Reliability function of a discrete memoryless channel at rates above capacity (Corresp.)

Asymptotically coincident upper and lower bounds on the exponent of the largest possible probability of the correct decoding of block codes are given for all rates above capacity. The lower bound sharpens Omura's bound. The upper bound is proved by a new and simple combinatorial argument.     

Achievable rate for three-node discrete memoryless relay channel with generalized feedbacks

This paper studies the achievable rate for three-node discrete memoryless relay channel.Specifically in this mode,we explore two generalized feedbacks simultaneously:the source node actively collects feedback signals from the channel;and at the same time,the destination node actively transmits feedback signals to the relay node.These two feedback signals,which are called generalized feedback overheard from the channel that is likely to be noisy,induce that all the three nodes are in full duplex mode.The basic coding strategies of Cover and El Gamal are applied to the relay-source feedback transmission by the source forwarding the compressions of the channel output sequences at the relay node to the destination,and are also applied to the destination-relay feedback transmission to improve the decoding ability at the relay.Based on Cover and El Gamal coding,a new coding scheme adopting rate splitting and four-block Markov superposition encoding is proposed and the corresponding achievable rate is achieved.The proposed scheme is able to exploit two feedbacks simultaneously which can effectively eliminate underlying transmission bottlenecks for the channels.The derived achievable rate result generalizes several previously known results by including them as special cases.     

An improved achievable region for the discrete memoryless two-user multiple-access channel with noiseless feedback

An achievable region for the two-user discrete memoryless multiple-access channel (DMMAC) with noiseless feedback is proposed. The proposed region includes the Cover-Leung region, with the inclusion being, for some channels, strict. This inner bound is demonstrated for the ideal two-user Poisson multiple-access channel with noiseless feedback, in which case it is shown to improve on the Cover-Leung rate-sum.     

The capacity region of a multiple-access discrete memoryless channel can increase with feedback (Corresp.)

The capacity of a single-input single-output discrete memoryless channel is not increased by the use of a noiseless feedback link. It is shown, by example, that this is not the case for a multiple-access discrete memoryless channel. That is, it is shown that the capacity region for such a channel is enlarged if a noiseless feedback link is utilized.     

The discrete memoryless multiple access channel with partially cooperating encoders (Corresp.)

We introduce the communication situation in which the encoders of a multiple access channel are partially cooperating. These encoders are connected by communication links with finite capacities, which permit both encoders to communicate with each other. First we give a general definition of such a communication process (conference). Then, by proving a converse and giving an achievability proof, we establish the capacity region of the multiple access channel with partially cooperating encoders. It turns out that the optimal conference is very simple.     

The capacity region of the discrete memoryless interference channel with strong interference (Corresp.)

The capacity region of the discrete memoryless interference channel with strong interference is established.     

An improved upper bound on the block coding error exponent for binary-input discrete memoryless channels (Corresp.)

The recent upper bounds on the minimum distance of binary codes given by McEliece, Rodemich, Rumsey, and Welch are shown to result in improved upper bounds on the block coding error exponent for binary-input memoryless channels.     

The lowest-possible BER and FER for any discrete memoryless channel with given capacity

We investigate properties of a channel coding scheme leading to the minimum-possible frame error ratio when transmitting over a memoryless channel with rate R > C. The results are compared to the well-known properties of a channel coding scheme leading to minimum bit error ratio. It is concluded that these two optimization requests are contradicting. A valuable application of the derived results is presented.     

Capacity results for the discrete memoryless network

A discrete memoryless network (DMN) is a memoryless multiterminal channel with discrete inputs and outputs. A sequence of inner bounds to the DMN capacity region is derived by using code trees. Capacity expressions are given for three classes of DMNs: (1) a single-letter expression for a class with a common output, (2) a two-letter expression for a binary-symmetric broadcast channel (BC) with partial feedback, and (3) a finite-letter expression for push-to-talk DMNs. The first result is a consequence of a new capacity outer bound for common output DMNs. The third result demonstrates that the common practice of using a time-sharing random variable does not include all time-sharing possibilities, namely, time sharing of channels. Several techniques for improving the bounds are developed: (1) causally conditioned entropy and directed information simplify the inner bounds, (2) code trellises serve as simple code trees, (3) superposition coding and binning with code trees improves rates. Numerical computations show that the last technique enlarges the best known rate regions for a multiple-access channel (MAC) and a BC, both with feedback. In addition to the rate bounds, a sequence of inner bounds to the DMN reliability function is derived. A numerical example for a two-way channel illustrates the behavior of the error exponents.     

Capacity of a continuous memoryless channel with feedback

Shannon showed that the capacity of a discrete memoryless channel can not be increased by noiseless feedback. It has been conjectured that this should be true for a continuous memoryless channel, provided such a channel is appropriately defined. We precisely define such a channel from two mathematically different points of view and rigorously prove that its capacity can not be increased by feedback.     

Zero-error list capacities of discrete memoryless channels

We define zero-error list capacities for discrete memoryless channels. We find lower bounds to, and a characterization of these capacities. As is usual for such zero-error problems in information theory, the characterization is not generally a single-letter one. Nonetheless, we exhibit a class of channels for which a single letter characterization exists. We also show how the computational cutoff rate relates to the capacities we have defined