Interference channel with intermittent feedback

In this paper, we first study a two-user interference channel with generalized feedback. We establish an inner bound on its capacity region. The coding scheme that we employ for the inner bound is based on an appropriate combination of Han-Kobayash rate splitting and compress-and-forward at the senders. Each sender compresses the channel output that is observes using a compression scheme that is \`a-la Lim et al. noisy network coding and Avestimeher et al. quantize-map-and-forward. Next, we study an injective deterministic model in which the senders obtain output feedback only intermittently. Specializing the coding scheme of the model with generalized feedback to this scenario, we obtain useful insights onto effective ways of combining noisy network coding with interference alignment techniques. We also apply our results to linear deterministic interference channels with intermittent feedback.

In this paper, we have combined a game‐theoretic and an information‐theoretic notions to describe the selfish behavior of each user in a two‐user linear deterministic cognitive interference channel (LD‐CIC). The two‐user LD‐CIC is the simple case of the cognitive radio technology in the high SNR regime. This model is a solution to improve the spectral efficiency in software defined network (SDN) concept in 5G. In the two‐user LD‐CIC, the information bits of the primary/licensed transmitter is a‐priori provided at the cognitive/secondary/unlicensed transmitter. So that, the cognitive transmitter can cooperate and utilize the frequency spectrum to send the information bits of the both transmitters. In information‐theoretic approaches, full cooperation is assumed between transmitters for codebook and rate selection in this channel. This may not be a realistic assumption if transmitters are selfish and are willing to maximize their own benefit. In particular, we have defined the Stackelberg equilibrium (SE) region on the capacity region of the two‐user LD‐CIC to capture the behavior of each transmitter when they compete even though one of them is informed of the other transmitter information bits. We have implemented a two‐phase Stackelberg game with the primary and cognitive transmitters acting as the leader in the first phase, and the follower in the second phase, respectively. In this implementation, both transmitters are assumed to be selfish and only interested in optimizing their own pay‐offs. The SE region is characterized as a subset of capacity region in which the transmitters cannot gain more transmission rate by individually deviating from the SE strategy. The achievability of the resultant region has been configured using a randomized Han‐Kobayashi scheme for all the channel gains. Also, we have compared the obtained SE region with the previous equilibrium regions such as Nash equilibrium (NE) region of the linear deterministic interference channel (LD‐IC). The results have shown that the SE points on the sum‐rate of the LD‐CIC capacity region are more than the NE points on the sum rate of the capacity region of LD‐IC, so the SE region of the LD‐CIC is Pareto superior to the NE region of LD‐IC.

This work presents novel achievable schemes for the 2-user symmetric linear deterministic interference channel with limited-rate transmitter cooperation and perfect secrecy constraints at the receivers. The proposed achievable scheme consists of a combination of interference cancelation, relaying of the other user's data bits, time sharing, and transmission of random bits, depending on the rate of the cooperative link and the relative strengths of the signal and the interference. The results show, for example, that the proposed scheme achieves the same rate as the capacity without the secrecy constraints, in the initial part of the weak interference regime. Also, sharing random bits through the cooperative link can achieve a higher secrecy rate compared to sharing data bits, in the very high interference regime. The results highlight the importance of limited transmitter cooperation in facilitating secure communications over 2-user interference channels.

In this paper, we give an achievable scheme for a symmetric K-user linear deterministic interference channel with a rate-limited feedback from each receiver to its respective transmitter. For this model, the proposed scheme achieves a symmetric rate which is the minimum of symmetric capacity with infinite feedback, and the sum of the symmetric capacity without feedback and the symmetric amount of feedback.

The N +1 user, 1 ×N single-input multiple-output (SIMO) Gaussian interference channel where each transmitter has a single antenna and each receiver has N antennas is studied. The sum capacity within O(1) is characterized for the symmetric case where all direct links have the same signal-to-noise ratio (SNR) and all undesired links have the same interference-to-noise ratio (INR). The gap to the exact capacity is a constant which is independent of SNR and INR. To get this result, we first generalize the deterministic interference channel introduced by El Gamal and Costa to model interference channels with multiple antennas. We derive the capacity region of this deterministic interference channel. Based on the insights provided by the deterministic channel, we characterize the generalized degrees of freedom (GDOF) of Gaussian case, which directly leads to the O(1) capacity approximation. On the achievability side, an interesting conclusion is that the GDOF regime where treating interference as noise is found to be optimal in the two-user interference channel, does not appear in the N + 1 user, 1 × N SIMO case. On the converse side, new multiuser outer bounds emerge out of this work that do not follow directly from the two-user case. In addition to the GDOF region, the outer bounds identify a strong interference regime where the capacity region is established.

We consider a K-user interference channel in which the channel gains from transmitter i to receiver j > i are 0, resulting in a type of Z interference channel which we term the Complete K-user Z Interference Channel which has not been explicitly studied. We first consider the symmetric linear high SNR deterministic approximation of the Gaussian noise channel. For this model, we provide an outer bound which may be achieved, thereby obtaining the sum-capacity. The outer bound is obtained by providing two types of side-information: the first reduces the channel model to one in which each receiver sees a sum of the direct and interference terms, the second is reminiscent of the Etkin-Tse-Wang side-information for the interference channel. It is noted that the sum-capacity is a function of the number of users K and is larger than the “W” curve for the fully connected K-user interference channel, but reduces to it as K → ∞.

Interference alignment (IA) is a transmission strategy that attempts to exploit all degrees of freedom available at the transmitter or at the receiver in a multiuser channel. This paper proposes a new scheme named channel aided interference alignment. It makes use of the channel structure beside the linear interference alignment schemes to achieve the optimum degrees of freedom in a K user interference channel. In case the channel matrix does meet the specified structure, the proposed scheme achieves the optimum degrees of freedom at a finite signal to noise ratio and by using limited number of channel realizations; it turns to the usual linear vector interference alignment schemes otherwise. For the case of 3 user interference channel, it would be shown that if only one of interfering channel coeficients can be designed to a specific value, interferenfce would be aligned perfectly at all the receivers.

The paper in the first place reviews the information and the uncertainty measures of joint and marginal probability distributions of the sets and subsets of random events. Next it reminds on the relations of the unconditional and conditional entropy of joint and marginal distributions and their combinations. Then it elaborates the ways how these measures can be applied in the sea surface uncertainty evaluation, that is, how to gain the information from the wave properties visually observed and brought together in the global wave statistics. Furthermore, the examples offered demonstrate the computational procedures for the sea surface uncertainty evaluation and prospective usefulness of the information obtainable from the joint and marginal distributions of observed explicit and combined wave properties.

We provide a natural formulation of information theoretic games on interference channels. We analyze this game on a class of deterministic interference channels recently introduced to approximate Gaussian channels in the interference-limited regime. Our main result is a complete and simple characterization of the subset of the interference channel capacity region that can be achieved as Nash equilibria. We show that for all parameter values of the interference channel, there are always Nash equilibria which are efficient, i.e. on the boundary of the capacity region.

The capacity region of a class of discrete memoryless interference channels is established. The setup is similar to the class of deterministic interference channels studied by El Gamal and Costa. However, we relax certain conditions that were imposed by El Gamal and Costa. The capacity region of this class of interference channels also includes the capacity region of the discrete memoryless interference channels with strong interference. Finally, we extend the result to the case where both transmitters have a common message to transmit.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, the interference channel with common information (ICC), in which two senders need deliver not only private messages but also certain common messages to their <emphasis emphasistype="italic">corresponding</emphasis> receivers, is investigated. An achievable rate region for such a channel is obtained by applying a superposition coding scheme that consists of successive encoding and simultaneous decoding. It is shown that the derived achievable rate region includes or extends several existing results for the interference channels with or without common information. The rate region is then specialized to a class of ICCs in which one sender has no private information to transmit, and a class of deterministic interference channels with common information (DICCs). In particular, the derived rate region is found to be the capacity region for this class of DICCs. Last, the achievable rate region derived for the discrete memoryless ICC is extended to the Gaussian case, in which a numerical example is provided to illustrate the improvement of our rate region over an existing result. </para>

Magnetic recording channels are generally modeled as finite-state linear intersymbol interference (ISI) channels with additive white Gaussian noise and a binary input constraint. Lower bounds on the channel capacity have been computed by using this technique to estimate the information rates of optimized, order-r Markov input processes. RLL-constrained binary symmetric channel (BSC) and for two-dimensional finite-state ISI channels is proved in this paper

Deterministic channel models have recently proven to be powerful tools for obtaining capacity bounds for Gaussian multiuser networks that are tight in the high SNR regime. In this work we apply this technique to the Gaussian cognitive radio channel: a 2×2 interference channel in which one transmitter has non-causal knowledge of the message of the other, whose capacity region in general is unknown. We approximate the Gaussian cognitive radio channel at high SNR by an underlying binary linear deterministic channel model for which we determine the exact capacity region.

Digital communication systems offer high data rate and efficient transmission through the channel. Low bit error rates assess the quality of any communication system. Bit Errors occur as the result of Adjacent Channel Interference (ACI), Co¬Channel Interference (CCI) and Inter Symbol Interference (ISI) in the presence of Noise. These interferences are more prominent in mobile cellular systems owing to dispersive nature of the channel. Channel dispersion is attributable to multiple reflections in Mobile cellular systems. Equalizer technique is one of the important methods of countering the ill effects of channel. The response of the equaliser should be closely inverse of the channel response. Then the interferences are reduced to great extent by proper equalizers in the receiver end. It attempts to recover the original transmitted symbols at the receiver. In the absence of Channel knowledge, Adaptive equalizer offers superior performance. In this paper, Steepest Descent algorithm is discussed. This algorithm applied in Adaptive equaliser for time invariant and Mobile cellular channels. The efficiency of above algorithm in terms of Bit Error Rate versus SIR is analysed for both channels.

In a K-pair-user two-way Gaussian interference channel (IC), 2K messages and 2K transmitters/receivers form a Gaussian K-user IC in the forward direction (K messages) and another Gaussian K-user IC in the backward direction (K messages) which operate simultaneously in full-duplex mode. All nodes are permitted to interact, i.e. adapt current channel inputs to past received signals. We derive a new sum-rate outer bound for linear deterministic and Gaussian noise channels allowing for interaction, but show that for symmetric scenarios and certain interference regimes (moderately weak and strong), non-interactive schemes achieve to within a constant gap of this outer bound. That is, interaction for symmetric channels in certain interference regimes may only improve the sum-rate by a constant number of bits per channel use.