[mdasen]

I would say that cell signals mostly can't use the same frequencies for sending and receiving. The newer TDD allocations at 2.5GHz and above that carriers in the US are rolling out today do use the same for transmit and receive, but most of the old frequency ranges are exclusively up or down.

The difference is that cellular licenses generally offered equal bandwidth to up and down (ex. 10MHz down and 10MHz up). That's because they were originally designed for somewhat symmetrical communication: phone conversations where you assume each party is talking (sending) and listening (receiving) reasonably equally. With DOCSIS, it was designed assuming (correctly) that there'd be a lot more download traffic than upload traffic (which still holds true even in the era of remote work).