Path B modulation

Products PMP
1

It seems like after we rolled out  13.2 software that we see some of our 7-9 mile links not modulate as high on path B when they are realatively inactive.  Is this normal?  

I know the epmp gear will do something similar to this during periods of inactivity when SM isn't asking for data but I never noticed this with PMP 450 13.1.3 software.  Path A pretty much stays at 256 QAM but path B will shows a pretty consistant  16QAM modulation until the SM starts pushing some data.   SNR and signal rate look good.  Spectrum looks clean (3695.00).  I will say that the link tests push the expected bandwidth we want to see but I just want to know if this behavior is normal for an SM?  I'm using a KP Performace feedhorn/reflector and link is registered at 8X/6X.

Nate

2

Well, after much testing I can confirm that Path B does "sleep" when not in use and then lights up when you run data through it.  Didn't notice this happening on previous firmware but this is probably a  more efficient way to do things.  Just wanted to follow up on my post.  

3

Thanks Nathan. Let us know if there is anything else you need.

4

Nathan,

Both paths are always included in the modulation rate.

1X MIMO-B is QPSK on one path

2X MIMO-B is QPSK on both paths

4X MIMO-B is 16-QAM on both paths

6X MIMO-B is 64-QAM on both paths

8X MIMO-B is 256-QAM on both paths

13.2 added new MIMO-A modulation levels:

1X MIMO-A is QPSK duplicated on both paths

2X MIMO-A is 16-QAM duplicated on both paths

3X MIMO-A is 64-QAM duplicated on both paths

4X MIMO-A is 256-QAM duplicated on both paths

The radio tries to get the best throughput for the radio conditions.

When in-active what modulation rates do you see when idle and then after a link test?

-Charlie

5

Whoops. Copy/Paste error. My post is now updated with the right MIMO-A rate adapts.

6

The SM is always at full modulation on Path A.  Path B modulation "kicks up" to full modulation only after I see some traffic flowing and it will get full 256 QAM and pretty much stay there until traffic starts winding down.  I never noticed this happening before prior to 3.2 Firmware so I was just wondering if it was normal.  The link tests and speed tests give me the bandwidth I want to see but I just wanted to make sure it wasn't something going wrong.  So far, so good.  These 450's ROCK!