Clustered system switching method based on clustering multicasting

The invention discloses a clustered system switching method based on clustering multicasting. A relay is provided for collective switching of cluster users by using a way of clustering and D2D multicasting, business continuity of the cluster users during a switching process is ensured, and a transmission speed is improved. According to the method provided by the invention, a cluster head selection and clustering algorithm based on a analytic hierarchy process is adopted, mobility and remaining capacity of the cluster users are included into decision-making relevant factors; D2D coverage, a relative speed value and the remaining capacity are comprehensively measured, a terminal with the highest comprehensive evaluation index is acquired to serve as a cluster head, so that the quantity of the cluster heads can be effectively reduced, D2D communication time can be prolonged, and thus a network clustering structure is more stable, and the business continuity and transmission rates of the cluster users during a sw