Optimal Time Slot Allocation for Communicating Things Using Local Clocks

In the Internet of Things (IoT) scheme, networks of things can be massive in terms of size and scale. Indeed, in this new era of the Internet, networks can be made up of thousands or even millions of objects, thus constituting a dense network. Communicating objects in IoT are heterogeneous in terms of computing power, storage capacity and energy capacity. They are generally deployed in open environments and are exposed to malicious attacks and failures due to collisions and conflicts at the level of communication channels. All these problems lead to an increased energy consumption and thus, decrease the lifetime of the network. Resources must be managed and allocated efficiently to increase node longevity. To address the problems of collision and conflict, many research works have been conducted on distance-2 coloring for time slots allocation and it has been proved in many papers that this method is interesting for resource allocation. However with these solutions, there is a drawback with the use of a global clock and the need to exchange messages for time synchronization. In this paper, we propose a new optimal fully distributed algorithm for distance-2 tree networks coloring using local clocks. Our solution uses a local clock and no collisions nor conflicts are present. Thus, the solution we propose is more practical and more fault tolerant. We have simulated our solution using Omnet++ and compared it to existing works regarding time duration and the number of exchanged messages.