Dear Naser,
the corresponding functions are called in +network_generation/add_RRHS:
network_generation.RRH.on_arch_distribution(RRH_config,eNodeBs);
network_generation.RRH.predefined_distribution(RRH_config,eNodeBs);
You can modify them according to your convenience.
For the predefined setting, you will need to specify a vector of positions: [x1, y1; x2, y2; ….] in the config.
Best regards,
Martin.