D2D multi-hop routing : collision probability and routing strategy with limited location information

In this paper, we define a collision area in a heterogeneous cellular network for the purpose of interference management between Device-to-Device (D2D) and conventional cellular (CC) communications. Currently, most D2D routing algorithms assume synchronized accurate location knowledge among users and the base stations. In reality, this level of location accuracy is difficult and power consuming in Universal Mobile Telecommunications System (UMTS). In current LongTerm Evolution (LTE), there is no location information from the cell besides range information from time measurements. In the absence of accurate location information, we analyze the collision probability of the D2D multi-hop path hitting the defined collision area. Specifically, we consider the problem for three different routing scenarios: intra-cell, intra-cell to cell boundary, and cell boundary to boundary routing. As a result, we propose a dynamic switching strategy between D2D and CC communications in order to minimize mutual interference. The gradient-based switching strategy can avoid collision with the collision area and only requires knowledge of the current user and the final destination user’s distances to the serving base station

Double-tower Solutions for Higher Order Prescribed Curvature Problem

We consider the following higher order prescribed curvature problem on ${\mathbb{S}}^N :$ \begin{equation*} D^m \tilde u=\widetilde{K}(y) \tilde u^{m^{*}-1} \quad \mbox{on} \ {\mathbb {S}}^N, \qquad \tilde u >0 \quad \mbox{in} \ {\mathbb {S}}^N. \end{equation*} where $\widetilde{K}(y)>0$ is a radial function, $m^{*}=\frac{2N}{N-2m}$ and $D^m$ is $2m$ order differential operator given by \begin{equation*} D^m=\prod_{i=1}^m\left(-\Delta_g+\frac{1}{4}(N-2i)(N+2i-2)\right), \end{equation*} where $g=g_{{\mathbb{S}}^N}$is the Riemannian metric. We prove the existence of infinitely many double-tower type solutions, which are invariant under some non-trivial sub-groups of $O(3),$ and their energy can be made arbitrarily large.Comment: 34 pages, 0 figures. arXiv admin note: substantial text overlap with arXiv:2205.14482 by other author

Device-to-device communications in LTE-unlicensed heterogeneous Network

In this article, we look into how the LTE network can efficiently evolve to cater for new data services by utilizing direct communications between mobile devices and extending the direct transmissions to the unlicensed bands, that is, D2D communications in conjunction with LTE-Unlicensed. In doing so, it provides an opportunity to solve the main challenge of mutual interference between D2D and CC transmissions. In this context, we review three interconnected major technical areas of multihop D2D: transmission band selection, routing path selection, and resource management. Traditionally, D2D transmissions are limited to specific regions of a cell's coverage area in order to limit the interference to CC primary links. We show that by allowing D2D to operate in the unlicensed bands with protective fairness measures for WiFi transmissions, D2D is able to operate across the whole coverage area and, in doing so, efficiently scale the overall network capacity while minimizing cross-tier and cross-technology interference

1-{(1Z)-1-[3-(2,4-Dichloro­phen­oxy)prop­oxy]-1-(2,4-difluoro­phen­yl)prop-1-en-2-yl}-1H-1,2,4-triazole

In the title compound, C20H17Cl2F2N3O2, the triazole ring makes dihedral angles of 28.0 (3) and 72.5 (2)° with the 2,4-dichloro­pheny and 2,4-difluoro­phenyl rings, respectively, and the mol­ecule adopts a Z-conformation about the C=C double bond. In the crystal, C—H⋯O and C—H⋯N hydrogen bonds link the mol­ecules

Interference-aware multi-hop path selection for device-to-device communications in a cellular interference environment

Device-to-Device (D2D) communications is widely seen as an efficient network capacity scaling technology. The co-existence of D2D with conventional cellular (CC) transmissions causes unwanted interference. Existing techniques have focused on improving the throughput of D2D communications by optimising the radio resource management and power allocation. However, very little is understood about the impact of the route selection of the users and how optimal routing can reduce interference and improve the overall network capacity. In fact, traditional wisdom indicates that minimising the number of hops or the total path distance is preferable. Yet, when interference is considered, we show that this is not the case. In this paper, we show that by understanding the location of the user, an interference-aware routing algorithm can be devised. We propose an adaptive Interference-Aware-Routing (IAR) algorithm, that on average achieves a 30% increase in hop distance, but can improve the overall network capacity by 50% whilst only incurring a minor 2% degradation to the CC capacity. The analysis framework and the results open up new avenues of research in location-dependent optimization in wireless systems, which is particularly important for increasingly dense and semantic-aware deployments