Implementation of wrap around mechanism for system level simulation of LTE cellular networks in NS3

NS3 is a widely used open source dynamic event driven simulator to test new ideas, algorithms and protocols for networks including LTE cellular systems as guided by 3GPP specifications. This paper presents an addition to the LTE module of NS3 by implementing a wrap around mechanism for the standard 19-site cluster. In the wrap around mechanism, the network is extended to include six additional copies of the original hexagonal cluster, such that all cells have symmetric behavior. This will help obtain a more realistic interference environment. The wrap around mechanism is also extended to smaller 3-site and 7-site clusters which can be used for quick verification before simulating larger network. We also implement a wrap around mechanism for UEs, which allows cells in the simulation to have flexible boundary defined by radio conditions rather than fixed simulation boundary. The simulation results show that the wrap around mechanism, as implemented, provides statistically equivalent interference for all cells in the simulation area. This allows use of the entire simulation data providing statistically valid results in much reduced time.