# 450m slot grouping help!!

ok when running a link tst with multiple VCs at the bottom i have slot grouping. is this telling me that those  99 sm's are mainly connected to the 2 of the 7 groupings in my 450m?? if so how is that possible when those customers are spread throughout the 90 degree sector?  that doesn't make any kind of sense.

thanks for any help in advance!!

The way the data is presented often causes some confusion... let me try to explain.

What the table shows is actually like a "histogram" of how many SMs are grouped together, not which group the SMs are in.  In your case, about 2/3 of the time there are 5 SMs, and 1/3 of the time 4 SMs are grouped together.  Occassionally, you get 6 together.

There's a good thread discussing this here.

Hope this makes more sense.

is there a way to see the actual grouping being done by the 450m?

here is my linkplanner plotting as well

It's not quite that simple. In the link test to multiple VCs the Medusa tries to send data to ALL VCs in a fair and equal manner. It will be forming a new group every TDD. This group will have 4, 5 or 6 members in the case you have shown but the VCs making that group will be different every TDD. The number of permutations of 4 out of 99 is

P(n,r)=n!/(n-r)!, where n=99 and r=4. This works out to  90345024 possible sets. Now, of course, not all these sets will be valid because medusa needs at least 12 degrees of angular separation between each member of the set. Even so there will be a large number of possible combinations that will be valid. When passing user traffic, medusa calculates which VCs have data waiting to be sent and which of these can be best combined in groups to maximise the throughput of the system as a whole.

We are working on a new set of MUMIMO statistics data which will help users better visualise how it is performing on a live system.

With your 99 VCs being able to be grouped so that medusa can transmit to 4-6 VCs in the same slot you should get a good increase in traffic throughput compared to a non-medusa 450.

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