[Discuss-gnuradio] How can I get colliding packets?

Dear All,

does someone know how to get colliding packets? I know there is an example in gnuradio under gr-digital which is benchmark_rx.py that can capture the number of received packets. But I cannot see how to get the colliding packets. Does anyone has any idea how to get it?

Many thanks in advance.

BR,
Kirianto