Extended Generalized DoF Optimality Regime of Treating Interference as Noise in the X Channel

The simple scheme of treating interference as noise (TIN) is studied in this paper for the 3 x 2 X channel. A new sum-capacity upper bound is derived. This upper bound is transformed into a generalized degrees-of-freedom (GDoF) upper bound, and is shown to coincide with the achievable GDoF of scheme that combines TDMA and TIN for some conditions on the channel parameters. These conditions specify a noisy interference regime which extends noisy interference regimes available in literature. As a by-product, the sum-capacity of the 3 x 2 X channel is characterized within a constant gap in the given noisy interference regime.Comment: 5 pages, 2 figure

Fundamental Limits on Latency in Transceiver Cache-Aided HetNets

Stringent mobile usage characteristics force wire- less networks to undergo a paradigm shift from conventional connection-centric to content-centric deployment. With respect to 5G, caching and heterogeneous networks (HetNet) are key technologies that will facilitate the evolution of highly content- centric networks by facilitating unified quality of service in terms of low-latency communication. In this paper, we study the impact of transceiver caching on the latency for a HetNet consisting of a single user, a receiver and one cache-assisted transceiver. We define an information-theoretic metric, the delivery time per bit (DTB), that captures the delivery latency. We establish coinciding lower and upper bounds on the DTB as a function of cache size and wireless channel parameters; thus, enabling a complete characterization of the DTB optimality of the network under study. As a result, we identify cache beneficial and non-beneficial channel regimes.Comment: 5 pages, ISIT 201

Resolving Entanglements in Topological Interference Management with Alternating Connectivity

The sum-capacity of a three user interference wired network for time-varying channels is considered. Due to the channel variations, it is assumed that the transmitters are only able to track the connectivity between the individual nodes, thus only the (alternating) state of the network is known. By considering a special subset of all possible states, we show that state splitting combined with joint encoding over the alternating states is required to achieve the sum-capacity. Regarding upper bounds, we use a genie aided approach to show the optimality of this scheme. This highlights that more involved transmit strategies are required for characterizing the degrees of freedom even if the transmitters have heavily restricted channel state information

On the approximative optimality of treating interference as noise in multi-user networks

Trotz der generellen Effizienz der Interferenzdecodierung wird sie kaum in den praktischen Realisierungen angewandt. Stattdessen wird die auf der Behandlung von Interferenz als Rauschen (engl.: Treating Interference as Noise, TIN) basierende Herangehensweise angewandt. Vergleicht man dies mit den Anforderungen an eine Kommunikation über einen Punkt-zu-Punkt Kanal, setzt diese Vorgehensweise (TIN) keine weiteren Anforderungen voraus. All dies motivierte die Forschung, sich mit der Optimalität von TIN in unterschiedlichen Kanälen auseinander zu setzen. In dieser Arbeit wird die Optimalität von TIN in einem sehr fundamentalen Netzwerk untersucht. In diesem Netzwerk operieren ein Mehrfachzugriffskanal und ein Punkt-zu-Punkt Kanal über die gleichen Kommunikationsressourcen. Die daraus gewonnenen Erkenntnisse helfen uns, die Optimalität von TIN in größeren Netzwerken zu untersuchen. Um das zu zeigen wird als nächstes die Optimalität von TIN vollständig im M x 2 X-Kanal untersucht.Despite of the theoretical efficiency of decoding the interference in many channel, treating interference as noise (TIN) is the most common way of dealing with interference in the practice. This is mainly due to the fact that, compared to the point-to-point (P2P) channel, no additional computation is required by TIN; neither at the transmitters nor at the receivers in networks. Knowing the optimality of TIN might have significant impact on the complexity and performance of networks. All these facts motivated the researchers to study the optimality of TIN in different channels. In this work, we study first the optimality of TIN in a fundamental network in which a multiple access channel and a P2P channel share the same communication resources. The obtained insights can be extended to more general network. To show this, we characterize next the necessary and sufficient conditions on optimality of TIN in the so-called Mx2 X-channel in which M transmitters communicate with two receivers