TDMA (time domain multiple access) is how digital cellular worked before CDMA (code domain multiple access) took over. TDMA is an inferior system because it is possible in practice to get much higher utilization of bandwidth using CDMA.
The article is talking about SDMA (spatial domain multiple access) which is a way of allowing two transceivers to share the same frequency (and code in the case of a CDMA, or timeslot if TDMA) with reduced interference by shaping and processing the signals using arrays of antennas. The cheap-ass technique mentioned is not new and sounds like masters thesis or even senior project material, so the fact that this is a news article would be quite mystifying if i did not know that the society that i grew up in is devolving more rapidly that I could have ever imagined even 5 years ago.
P.S. This talk of full-duplex, chopping, etc. that everyone seems to be bringing up are pretty antiquated terms of art. Sort of like mentioning how your car has rack and pinion steering or a rear differential.