A novel cross-layer adaptation and QoS optimization in LTE-A and beyond networks Among the major challenges in 3GPP LTE-A (3rd Generation Partnership Project Long Term Evaluation) and beyond networks are the convergence of services towards IP technology, the quality of service (QoS) and the maintenance of multimedia flows transmitted on wireless networking for mobile and heterogeneous users. In this environment, multimedia services must face various disadvantages generated by the unreliability of the wireless channel shared by several users. These new characteristics impose new requirements when designing wireless protocol, such as in LTE-A networks, where protocols must be dynamically adapted with the continuous changes of the radio operator state channel and seek at the same time to meet the QoS requirements with the supported applications. In this context, we will propose a new cross layer and performances optimization of the 3GPP LTE-A system. Our major contribution consists to set up coordinated interactions between high layers applications representing for example video streaming and those of low layers, such as network, MAC (Medium Access Control) and physical layer. The information exchange between these layers will lead to optimize the application operation according to the changes observed on the radio operator channel. Thus, this solution would reduce the probabilities of the application dysfunction or interruption, while respecting the QoS constraints (time, throughput, PLR (Packet Loss Ratio) and maintain a constant flow for the user.