Injective edge-coloring of subcubic graphs

An injective edge-coloring [Formula: see text] of a graph [Formula: see text] is an edge-coloring such that if [Formula: see text], [Formula: see text], and [Formula: see text] are three consecutive edges in [Formula: see text] (they are consecutive if they form a path or a cycle of length three), then [Formula: see text] and [Formula: see text] receive different colors. The minimum integer [Formula: see text] such that, [Formula: see text] has an injective edge-coloring with [Formula: see text] colors, is called the injective chromatic index of [Formula: see text] ([Formula: see text]). This parameter was introduced by Cardoso et al. [Injective coloring of graphs, Filomat 33(19) (2019) 6411–6423, arXiv:1510.02626] motivated by the Packet Radio Network problem. They proved that computing [Formula: see text] of a graph [Formula: see text] is NP-hard. We give new upper bounds for this parameter and we present the relationships of the injective edge-coloring with other colorings of graphs. We study the injective edge-coloring of some classes of subcubic graphs. We prove that a subcubic bipartite graph has an injective chromatic index bounded by [Formula: see text]. We also prove that if [Formula: see text] is a subcubic graph with maximum average degree less than [Formula: see text] (respectively, [Formula: see text]), then [Formula: see text] admits an injective edge-coloring with at most 4 (respectively, [Formula: see text]) colors. Moreover, we establish a tight upper bound for subcubic outerplanar graphs.

Conceptual Model of HF-Band Packet Radio Network Control System

The author develop the conceptual control system model to ensure the sustainable projected promising packet radio network HF-band operating. It is proposed to implement the control functions at the Element Management System level on the basis of automated radio centers, and to implement the Network Management System level management functions on the basis of a dedicated server. Such a management approach allows you to build a hierarchical centralized radio network management system architecture. We can observe a simulation modeling for the developed algorithms of the selected radio network control functions. The paper presents the simulation results, namely probabilistic-temporal characteristics of the processes reliability, routing and functioning under attacks.

A Research to Ad-hoc and Wireless Sensor Network

In the current wireless network technology, the most important research is Ad-hoc, and the most promising is the WSN. Ad-hoc which develops on the basis of packet radio network is a wireless mobile network with self-organizing, peer to peer and multi-hop. WSN combines Ad-hoc and sensor technology to collaboratively perceive, collect and process the message of sensing objects in the coverage area of network, and send to the viewer.

Effective throughput of AX.25 protocol

AX.25 protocol belongs to the HDLC protocols family and is used, among others, as a data link layer in an amateur Packet Radio network. The paper presents a simple analytical model developed on the basis of protocol frame exchange rules. Then, we compare analytical results to the experimental ones achieved using various different types of TNC controllers that act as network interfaces for Packet Radio network. In the experimental part we focus on both hardware and software properties of TNC that have influence on the effective throughput of the network.