The swift advancement of 5G networks has resulted in the incorporation of heterogeneous network architectures that combine diverse communication technologies. One of the emerging paradigms in the field is Device-to-Device (D2D) communication, which shows promise in facilitating direct communication between devices and improving overall network efficiency. Nevertheless, the task of enhancing throughput in 5G heterogeneous networks that incorporate device-to-device (D2D) communication presents notable obstacles. This research article introduces a new algorithm that focuses on D2D communication mode selection and resource optimization in order to attain maximum throughput. The algorithm under consideration integrates various strategies including channel quality assessment, mode selection, resource allocation, interference management, and mobility management. The decision-making process for mode selection and resource allocation takes into account important factors including channel conditions, interference, and Quality of Service (QoS) requirements. The performance of the proposed algorithm is assessed through a series of comprehensive simulations, wherein it is compared to existing approaches. The findings indicate that the algorithm successfully enhances throughput, efficiently handles interference, and fulfills QoS (Quality of Service) demands. The present study makes a valuable contribution to the domain of device-to-device (D2D) communication within the context of 5G networks. It offers a comprehensive solution aimed at optimizing throughput and improving overall network performance.