Low Aggregate

On our two 900 MHz systems, our aggregate, even with a good signal, is only about 1.9Mbits. Any idea what’s going on?

Please take screen shots of the AP Configuration pages, put them on a server and post a link to them here.


Here you go Jerry…

How many sites
How many AP’s per site
How far apart are the AP sites?
How many subs per AP
What is your BW to the internet
How is the AP connected to the Internet

Posted: Tue Feb 13, 2007 11:09 pm Post subject:


How many sites
How many AP’s per site
1-900 at each; plus one 5.7 at one; 2 5.7’s at the other
How far apart are the AP sites?
8 miles
How many subs per AP
Just one or 2 on each of the 900 AP’s; several dozen on the 5.7’s
What is your BW to the internet
Not sure. 5.7 BH from one sight to the other, then a BH into town
How is the AP connected to the Internet
BH to town, then out on DS3

I see the 900AP is generating sync. What are you doing for sync?

Each Tower should have a CMM or SyncPipe to sync all the radios. The 900’s especially need to be in sync as they can hear each other for a very long way

Your configuration should look like this:
Internet+BHS-A ----->BHM-A+GPSSync+AP’s+BHM-B ------>BHS-B+GPSSync+AP’s

I would start with BHM-A set to 25% downlink, and BHM-B set to 75% downlink. This will allow 75% of the two BH links to flow from the Internet to the Subscribers.

All AP’s in each band should be configured with the same downlink, max distance, and control slots (i.e. all 900’s the same, all 5.7’s the same)

The BH’s should be at opposite ends of the spectrum and physically as far apart as possible. The 5.7 AP’s should also have as much distance from the BH’s as possible and be set in the middle of the spectrum

This is our 5.7 layout and it works very well:
5735.0 BH-B (Tower 1 to Tower 2)
5765.0 AP East (Tower 2)
5775.0 AP North Northwest (Tower 1)
5795.0 AP West, AP North East (Tower 1)
5805.0 another company’s link
5820.0 another company’s link
5840.0 BH-A (Head end to Tower 1)

In order to get BH’s to CoLocate with AP’s you need separation.

What kind of speeds are you getting with the 5.7’s?

I did some checking with the guy who set our system up. Our backhauls and 5.7 AP’s are working great…great speed, throughput, etc.
The 2 900 AP’s are at separate sights, about 8 miles apart. He says they don’t need to be synced.
What kind of aggregate numbers are you getting?

Shut down one AP and turn it into an SM and put it on the same color code as the other AP. If it registers to the other AP then they definately need to be sync’d.

We see anywhere from
1.5M x 600k @ 10+ miles
3M x 700k under 10 miles.

Performance will vary depending on antenna’s and distance.

HW scheduling provides better performance. 2X rate requires 10dB above the noise floor for a consistent link.

I have said it many times and will again One of the if not the most important part of the system is.


8 miles is nothing to the 900. In one area I have 11 900 AP’s in a 15 mile radius all sites sync’d no proble. I have customers 20 miles away from the AP who are running in 2X at about 2.8M down and 1.2M up set at 65% down -72.

Attitude0330…I couldnt have said it better! SYNC, SYNC, SYNC.

Even if you are using omni AP’s I would suggest sync because two 900 MHz AP’s mounted on a tower can see a long way and they may interfere with one another. This may be your issue. Another, make sure you are using hardware scheduling with 2X enabled.