Bus-type network has only single channel, if frequency division multiplexing technology is used in bus-type network, could it be changed into star-type network? It seems that the architecture and protocol of star-type network is more simple than bus-type one. For example, star-type network need not CSMA.
If you use a hub, then your topology will be physically star but logically bus.
So If you use a switch your topology will be logically start and it will not need CSMA/CD as you said. So if you use FDM on a bus topology, it can be considered as logically star as it is impossible for collisions to occur and you will not need CSMA/CD.
The used protocol in case of bus is token bus IEEE 802.5