TDD Mode
ePMP links operate using TDD. The links employ a TDD cycle in which the AP determines which
Subscriber Modules may transmit and when based on the configured downlink/uplink ratio (duty cycle).
TDD Variable Ratio is available from day one.
The feature allows to configure TDD ratio values in the range 75/25 - 30/70 with a step 5.
Flexible mode is available for the configuration as well.
Defects Fixed
Tracking ID
Products
Description
AXG-7765
All
SMs were not able to associate with an AP with the âERROR PROP DELAY CALCULATIONâ error message.
AXG-8068
All
SMs were not able to connect with âINVALID SECURITY KEYâ the disconnect error message.
AXG-8207
All
General stability improvements for devices operating in the TDD mode.
AXG-8258
All
Spectrum Analyzer stability improvements
AXG-8380
All
Combined SNR/RSSI were calculated incorreclty in rare occasion
AXG-8381
All
RSSI values became lower if the device was under noise injection.
AXG-8414
Force4625
GPS page was missing on UI
AXG-8468
Force4525, Force4625
Stability Improvements for Force4625 and Force4525 operating in TDD mode.
AXG-8467
All
SMs association takes long time in TDD mode.
AXG-8450
All
Incorrect Uplink RSSI calculationâŚ
AXG-7319
All
SMs disconnect when operating in TDD mode.
Limitations
Itâs not recommended to use Force4xxx SMs in NAT mode. Some configuration changes in NAT mode may require SMâs reboot to be applied.
I noticed in the 5.6 beta the cautionary limitation to not use SM in NAT mode and understood that to be because it was still in beta. Now I see 5.6 with TDD is in general release but still has the NAT mode limitation. What is the timeline to correct that issue? We are currently using SMs in NAT mode and intend to continue to do so moving forward. Can the issue regarding SM in NAT mode be better explained?
We are working on the issue.
Actually we are testing the fix right now.
And 5.6.1 Beta will be released shortly(7-10days).
If you are enabling Separate Wireless interface it doesnât come up until the reboot of the SM.
That can happen with any other networking parameter configuration in NAT mode.
Rebooting the SM solves the issue.
TCP performance seems to have improved since the TDD alpha/beta we were running in December.
Wondering how much SNR before we should expect to see modulations higher than MCS7 on a 40Mhz channel?
On ePMP3000 Iâve got subs showing MCS8 as low as 28 SNR and MCS9 as low as 30 SNR, yet Iâve got a sub connected to 4500 not getting more than MCS7, despite 31 SNR.
Hi guys, there is a future plan to add âAccess Point TDDâ function in the 4600C and 4625?
We have some F300-25 in âAP TDDâ in our main tower doing small sectors connecting other towers or special clients with a limited 12 SM whith excellent results.
Thanks!
So far there havenât been any plans to add lite PtMP AP support for the F4525/4625/F400c/425 radios. If enough people ask though, they might relent like how they did with the low end e3k radios and eventually add in support for it.
I want it all and I want it now! LOL Seems strange not to add that functionality to the ePMP4000 line after all the whining on the ePMP3000 for the feature. The need has not gone away. We would definitely use it in small deployment scenarios.
Just again proves that Cambium doesnât see us as âvalued partnersâ. Weâre not âpartnersâ if itâs not Cambium and us, working together to capture our clients. Instead Cambium sees US as the prey to be preyed upon.
It demonstrates they would literally remove every single feature out of these radios, and sell each and every one of them back to us with a separate license fee if they could.
NOTE: I STAND CORRECTED⌠Cambium DOES say below that this feature has not been âremovedâ and that itâs is coming, and just not mature currently. I was wrong.
ninedd, I think thatâs a bit extreme. We appreciate the business of all partners who purchase Cambium. Iâm not on the product team, but I can say that the team has to prioritize development efforts based on impact and demand and right now there are higher priorities than AP TDD functionality in SMâs. An example is interoperability with prior generations of ePMP. Understandably, the AP TDD for SMâs is a use case that would benefit certain scenarios and will likely be committed to the roadmap in the future.
OK - so youâre saying that this hasnât been âdecided to be removed by choiceâ again? That itâs simply ânot available yetâ? If thatâs the case, then I stand corrected.
Hi ninedd, yes that is correct. I just confirmed with PLM that they will commit to the development effort to add this feature into the e4k platform so e4k SMâs can operate in AP TDD mode.
Is the e4k in TDD or WLR mode? Iâve generally had better latency/jitter in WLR mode for lower numbers of clients. TDD mode seems to have higher overall latency, especially for those clients with poor modulation/RSSI. That being said, TDD scales better and at higher client counts, average latency is better for everyone in our experience. Thereâs def room for TDD optimization and Iâm sure that theyâre working on this. ePTP mode for e4k works very well and latency/jitter is comparable to e3k.
Since updating to 5.6.0 when doing a spectrum analysis when I select a specific range it doesnât show the area that I have selected. Had to downgrade to 5.4.2 just to do specâs when we just put up some 4500âs Anyone else seeing this issue?
