Much of the functionality of
pre-cog has been ported to gr-mac, which works with "core" features of
gnuradio like the new message passing API.
We've also added a burst_tagger block that converts length tags to tx_sob/tx_eob tags as Martin suggests.Of
course, for real TDMA you will need to add tx_time tags, in addition to
adding the tx_sob (doesn't actually do much
IIRC) and tx_eob flags (makes the Tx switch off quickly after tx).
tx_time tells the USRP exactly when to start streaming and the value you
assigned here would take into consideration slots, guard intervals,
interface latency, processing jitter, etc. The block that adds these
tags will also have to track time
and schedule when these tags are added and samples go out.
If you plan to make a TDMA
block, perhaps you can contribute that back to community through
gr-mac. Balint and I were also planning to develop one, but I can't
make any specific promises on out timeline. We certainly welcome and
encourage more contributions! You can see my GRCon13 presentation for more
information on how tx_eob/time tags work, and how the FHSS/TDMA designs
worked (could be vastly improved):
http://gnuradio.squarespace.com/storage/grcon13_presentations/grcon13_malsbury_phy_mac_primer.pdf
https://github.com/jmalsbury/gr-machttps://github.com/balint256/gr-mac