Questions regarding Throughput vs Path Loss Tests for wireless APs

[dcamps]

Dear all,

I would like to know a bit more information about the wireless tests that you have performed in order to obtain the Throughput vs Path Loss graphs for the different 802.11n APs.

These are my questions:

1- I see you have used a channel emulator from Azimuth. Which TGn channel model were you using in your experiments ?

2- Could you give a bit some more details on the capabilities of the 802.11n STA acting as client in these experiments ? e.g. number of antennas ? any information on aggregation capabilities ?

3- Finally I am a bit surprised that the throughput saturates to these low values. Do you have any idea why ?
- Were you using the APs in 11n greenfield mode?
- Do you know if the APs were using aggregation capabilities?
- Did you observe the modulation and coding schemes that were being used by the APs? For instance at low path losses (50-60 dBs) if the AP and the client have 2 antennas, the APs should be using 2 spatial streams achieving PHY layer throughputs above 100Mbps in a 20Mhz channel.

Thanks!

Daniel

 

[thiggins]

1- I see you have used a channel emulator from Azimuth. Which TGn channel model were you using in your experiments ?

Butler

2- Could you give a bit some more details on the capabilities of the 802.11n STA acting as client in these experiments ? e.g. number of antennas ? any information on aggregation capabilities ?

The clients used are the "matching" adapters from the same product family as the router. Details are provided in the product review.

3- Finally I am a bit surprised that the throughput saturates to these low values. Do you have any idea why ?
- Were you using the APs in 11n greenfield mode?
- Do you know if the APs were using aggregation capabilities?
- Did you observe the modulation and coding schemes that were being used by the APs? For instance at low path losses (50-60 dBs) if the AP and the client have 2 antennas, the APs should be using 2 spatial streams achieving PHY layer throughputs above 100Mbps in a 20Mhz channel.

No idea whether APs were using greenfield mode, since that is not exposed in router Admin settings.

Most products, regardless of number of antennas use 2 spatial streams. Some products have 1T2R STAs.

Except for bidirectional tests, I run only one pair at a time. Some products may require multiple connections to achieve maximum throughput. Also I use TCP/IP, not UDP for testing.