Dear Chai,
please make sure that all parameters are set accordingly. If you want to simulate with three cells, you also need to define nodes within the topology correspondingly. For a three cell simulation you should have something like this
scStr.topology.nodes = ['BS1,BS2,BS3,UE1,UE2,UE3'];
In order to solve this issue, please post your scenario file such that I can check it.
best
Stefan