5G has significant advantages in emergency communications. If it is directly deployed in the disaster area, there are still some disadvantages such as large data traffic and long service delays. This paper analyzes the needs of public safety network (PSA), and studies the application of dynamic messaging delivery, network slicing, C-RAN, and D2D in 5G PSA. Then, this paper puts forward two 5G emergency rescue solutions, one is the portable 5G private network and 5G public network collaboration, and the other is the public network UPF sinking. Finally, we compare these two solutions according to the needs of the emergency management department. The conclusion is that the portable 5G private network and 5G public network collaboration solution can be independently deployed locally. It does not have the limitations of the 5G public network UPF sinking solution but has the same network functions, which is more in line with the requirements of the emergency management department.KeywordsEmergency communicationsPublic safety network (PSA)Lightweight 5GC5G private networkUPF sinking