| During emergencies, the availability of telecommunications is crucial and essential for network users of Public Safety Networks (PSN). Therefore, during such times, the need of information exchange increases dramatically. Therefore, access to the radio medium becomes congested quickly. Unfortunately, during these times, the resources dedicated for PSN does not seem to be sufficient to meet all new bearers' requests. LTE networks are therefore contributed to address this issue by providing access to Shared Commercial Radio for PSN. This access is done with some prioritization to improve PSN communications during emergencies. However, this access should not monopolize all the commercial network resources.;In addition, the LTE technologie allows the use of communications Device-to-Device which is the exchange of information directly between devices without having to go through the eNodeB. Hence, the D2D communications should be used to address the congestion issue, especially during disasters.;Moreover, improving the performance of PSN networks is not limited in the reliable management of radio resources. The allocation of bandwidth resources at the Backhaul network and the core network of LTE should also be improved.;In this thesis a new innovative model has been designed to improve the performance in Public Safety networks over LTE heterogeneous networks. This model has ten solutions. It operates in the three parts of the LTE network, namely the access network, the backhaul network and the core network of LTE.;Our various solutions have all been validated by simulations, and all have made an improvement compared to classical approaches or compared to other existing approaches in the literature. |
