The invention claimed is:1. A method of a communication terminal, the method comprising:receiving a rate control parameter sent from a core network node via an Access and Mobility Management Function (AMF) node and an Access Network (AN); andusing the rate control parameter as a limit of uplink user data that is sent on a control plane.2. The method according to claim 1, wherein the rate control parameter indicates limiting the number of messages that the communication terminal sends during a predetermined period.3. The method according to claim 1, wherein the communication terminal limits the number of messages that the communication terminal sends during a predetermined period by using the rate control parameter.4. The method according to claim 1, wherein the communication terminal limits a rate of the uplink user data by using the rate control parameter.5. The method according to claim 1, wherein the communication terminal comprises an Internet of Things (IoT) terminal.6. A communication terminal comprising:a receiver configured to receive a rate control parameter sent from a core network node via an Access and Mobility Management Function (AMF) node and an Access Network (AN); anda processor configured to use the rate control parameter as a limit of uplink user data that is sent on a control plane.7. The communication terminal according to claim 6, wherein the rate control parameter indicates limiting the number of messages that are sent during a predetermined period.8. The communication terminal according to claim 6, wherein the processor limits the number of messages that are sent during a predetermined period by using the rate control parameter.9. The communication terminal according to claim 6, wherein the processor limits a rate of the uplink user data by using the rate control parameter.10. The communication terminal according to claim 6, wherein the communication terminal comprises an Internet of Things (IoT) terminal.