[AlotOfReading]

The point is that Bluetooth descends from an independent intellectual heritage. No one was aware of her patent. The original experiments with Frequency hopping happened in the early 1900s with Marconi and Tesla. FSK was used for military radio in the 1930s and by the 40s had trickled out into widespread knowledge. Here's an example of a trade magazine from 1948 describing FSK [0] citing military work in the late 1930s, which also says

    It may appear to the reader that this recent advance in telegraph technique is a rather obvious one

Going on to say that it's little studied because there simply isn't a good method to synchronize the transmissions yet. That's what Hedy and others were trying to solve, but the widespread solution would come from the independent invention of Barker codes in 1953. Many decades later when the people at Ericsson were designing what became Bluetooth, they looked at the FCC requirements that had been written to accept FSK radioteletypes in widespread use after the war and common best practices for radio system design.

[0] https://worldradiohistory.com/UK/Wireless-World/40s/Wireless...