HE MU-RTS and CTS deep-dive

The second powerpoint series in my deep dive into the HE/802.11ax protocol is about the Multi User Request to Send (MU-RTS) and Clear to Send (CTS) process.

MU-RTS is one of the new Trigger Frames in the HE process and will be used instead of the legacy RTS.

I’ve have rewritten the slides some times while I have discovered new items during my interpreting of the IEEE802.11ax draft, so the coherence of the slides could have been better.
If I have interpreted it wrong, please tell it to me

My lab is consisting of Cisco equipment and Cisco have not implemented this functionality yet, so nothing is tested in real life.

I hope it useful



2 thoughts on “HE MU-RTS and CTS deep-dive

  1. Thanks for a detailed presentation on the MU-RTS . My comment is on the simultaneous CTS sent from the users called out in the MU-RTS type of trigger (slide 18). You have mentioned that the CTS from the different users will be separated by a MIMO receiver capability by the AP. In my opinion, this is not correct. The reason is that for the MIMO like capability to work (in fact this would be UL MU-MIMO like operation), there are specific LTFs (HE-LTFs, preambles) which have to be sent by the different STAs who are sending the CTS in response to the MU-RTS. Moreover, this would also limit MU-RTS to a UL MU-MIMO handling capability at the AP which is also not mandatory for MU-RTS support. The AP can handle multiple CTS coming on the air because of the exact same bits being sent by the parallel CTS sent by the different users, this will be received by the AP like multipath transmissions sent by a single transmitter. Thus the AP can decode the same CTS being sent by the different STAs without knowing which of the STAs has sent the CTS. Hope this is clear. Look forward to your comments.


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