A method for simulation of behavior and/or performance of an internet-of-things system uses an internet-of-things simulation environment. The simulated internet-of-things system includes at least a plurality of simulated internet-of-things communication devices in a communication network providing radio coverage in a predetermined geographical area. Via transmission of internet-of-things payload data between the simulated internet-of-things communication devices and the communication network, the simulated internet-of-things system provides a simulated internet-of-things service.