A habitat called the hoop was supposed to solve housing problems in a futuristic city. Something doesn't work and the hoop becomes a dumping ground for undesirables. There is a curfew for hoopers to be back in hab and out of city proper. A goth like cult called thumpers get brain implants that thumps in their head and they all silently bang heads in sequence. Not great but unique and I can't find any evidence it ever existed.
We first meet the eponymous heroine when she lives in a floating city called, as you say, "The Hoop". It is very much a ghetto with lots of cults. Some of them do indeed have a hypnotic beat implanted in their heads (but they are called "Different Drummers" not "Thumpers").
Halo eventually leaves the hoop and starts to travel. But although she keeps hoping to find somewhere better, she finds she has to keep moving on.
Tragically the story is unfinished.