Is the wifi dual band or single band?


#18

Why replace the card itself?
I would only remove the signal splitter/combiner and use the 2 open holes.


#19

The WLE200N2 just has 16dBm output power - this seems to be not that much unfortunately.


#20

It may be the WLE200N2-23 with 23 dbm per chain (26dbm total). The link to the WLE200N2 above is the half-size one.

And even the WLE200N2 half-size has 16 dbm per chain so 19 dbm total. More than enough (allowed) even with 3 dbi antennas for most parts of the world.


#21

Please forgive my understanding regarding the combiners, but does this all mean that replacing both cards with a single card such as: http://www.compexshop.com/product_info.php/products_id/460
"is not" or “maybe not” possible due to the mother board or other design aspects?


#22

The WLE200N2-23 would be great. 16/19dbm ist not that much. I really would like to avoid building up meshes / bridges etc. But so long we are able to replace it should be fine.


#23

Removing the combiners is possible. Replacing the cards is also possible.

But why replace the WLE900VX with a WLE600VX?
Remove the combiners and the WLE200N2 and keep the WLE900VX.

The WLE600VX is based on QCA9882 and has 2 streams.
The WLE900VX is based on QCA9880 and has 3 streams.
Both chipsets are the same hardware generation.


#24

according to http://www.compexshop.com/product_info.php/products_id/452 the WLE900VX-7A (not sure if 7A or industrial version is used here) is “Simultaneous Dual Band 802.11ac” which should mean the WLE200N2 is not needed at all, no?


#25

i got confused by that website, too… no, they aren’t “Simultaneous Dual Band”, they can only transmit on either 2.4 OR 5 GHz at the same time.

i’m not sure, if simultaneous dual band mcpi-e cards even exist (although i read it somewhere)


Turris 1.x wi-fi upgrade balíček
#26

compexshop is not operated by compex and sometimes they have errors in their descriptions. http://www.compex.com.sg/ is the homepage of compex.

I have not seen any and i doubt any real ones may exists.
Two single sided half-sIze miniPCIe cards plus a PCIe bridge may fit on one full-size double sided miniPCIe card. So 2 cards on one may work and count as simultaneous dual band but in the end they are 2 cards and a bridge chip.

They don’t make sense either. A multi radio single interface card would mean you lose usable bandwidth because it is one interface. A multi radio multi interface card would work like the bluetooth + wifi or umts combo cards. 2 devices in one case with 2 external interfaces (miniPCIe for WiFi and USB for bluetooth or umts) possibly routed through a bridge. This may exhaust the bandwidth on the PCIe side and limit there. This is no problem for NGFF/M.2 cards with 2 or 4 PCIe Lanes but miniPCIe has only one lane.


Turris 1.x wi-fi upgrade balíček
#27

Thanks very much for sorting me out on that error. I got sucked in by that statement on the compexshop site, just shows that if one is not up to speed on a particular tech aspect it is easy to be caught out by advertising!!!


#28

In order to improve the 2.4GHz signal reach/strength, I plan to replace the pre-installed WLE200N2 (16dBm) half-size module with the more powerful full-size WLE200N2-23 (23dBm) module.

Will it just be a matter of replacing the module in oder to achieve the better performance? Or are there limitations within the OS which prevent the utilization of the more powerful card?


#29

you might need to patch the regulatory database in the ath9k driver, but that’s illegal, of course :wink:


#30

:cold_sweat: Here come the newbie questions:

I am struggling here to figure out what that means on a functional level. So…

So: 3 transmit and 3 receive radio chains (no antennae amount mentioned); does that actually mean that the radio can communicate with 3 devices (full duplex) at the same time? Or does it mean it uses all three antennae to tripple the bandwith for a single signal (or either varying on use-cases)?

Could someone enlighten me (preferably with functional examples (I have googled watched vids, but most are fairly fundamental and/or MIMO seems to be used in various ways)?

Also; what is the use of having 2 radios (of which one is even dual band)? Can it be considered to be “tripple-band”-like (when considering them combined)?

(I did google, watched videos and read a lot of articles, but - although I kind of understand better it also confused me further).


#31

Basics

First: Wifi is always half-duplex. The expensive backhaul wifi devices use 2 wifi links (think of 2 cards per device) to get full duplex.

Transmit and Receive chains means there are multiple independent streams of data.

A radio chain connects the wifi chipset to an antenna. Take the greater number of chains and you have the count of anntennas. Anything up to 11g was basically 1x1:1 (1 antenna), 1x2:1 (Main antenna transmits always, second antenna is receive only) or 2x2:1 (transmit antenna switchable).

11n

11n came up with 3 things. First it added higher speed (72.2Mbps instead of 54 Mbps). Second it made the channels optionally larger (40MHz) and reached 150 Mbps this way. Third it added up to 4 spatial streams multiplying the basic bandwidth (72.2 or 150 Mbps) by the number of spatial streams. These are only an option if both ends support this. Yes, 802.11n allows for 600Mbps. The Compex WLE1200v2-22 is capable of this.

Example:

Channel width is 20MHz like most real 2.4GHz 11n networks are. There are 3 mobile phones with a 1x1:1 config and a notebook with a 2x2:2 config. The access point has a 3x3:3 config.

I assume all devices download data and get equal air time for receiving data (this is not reality but simpler for the sample).

How fast can they receive their data?

The notebooks gets a quarter of the 144Mbps. The mobile phones get a quarter of 72Mbps. So total rate is (3*72+144)/4 = 90 Mbps. Take away all overhead and your are far away from the advertised 450 Mbps of the access point.

Taking 40 MHz channel width and a 3x3:3 card in the notebook the total bandwidth would be (3*150+450)/4 = 225 Mbps. The half of the advertised bandwidth.

11ac

Then came 802.11ac and added even more bandwidth (93.3 Mbps instead of 72Mbps), even wider channels (up to 160MHz) and even more spatial streams (up to 8). This means up to nearly 7 Gbps for a 8x8:8 device. Interesting side-node: 3.4 Gbps are possible with a 2.4GHz 802.11ac wifi if you use all 13 channels as one big 80MHz channel.

MU-MIMO

802.11ac also added MU-MIMO.
The Compex WLE1216v5-23 is a sample for a 5GHz only card with MU-MIMO.

What does this change? It enables using the spatial streams in parallel for different devices.

Example continued

Taking the example above and making the access point MU-MIMO capable but remove one spatial stream and keeping everything else it gives the following:

2 spatial streams could be used at any time so the total bandwidth would be 144 Mbps.

If this were using 40 MHz channel width and the 3x3:3 card in the notebook it would go up from 225 to 300. Yes this is faster even with less spatial streams.

specific answers

This will have at least have 3 antennas.
This means it can support up to 3 spatial streams.
If this devices does not support MU-MIMO it will not support 3 devices in parallel.
Wifi is never full duplex.
Triple the bandwidth for one signal is a better analog.

There are different techniques for MIMO.
One is for spatial streams giving more bandwidth. This is used since 802.11n.
It may also be MU-MIMO giving the option to talk to different devices at the same time. This is available in a few 802.11ac cards and also used in most mobile networks that use code division like CDMA or UMTS.

The use is to support older and cheap devices that are unable to support 5GHz wifi like netbooks, IoT devices, your old mobile phone and many more. They don’t support 11ac so using it with 2.4GHz does not make sense.
The second card is dual-band because the chipsets are. They have this feature and restricting it would be useless.
Why use 2 cards? Because all ac-devices i have seen support 5GHz so you have higher speed and less polluted bandwidth available. Your older 5GHz 11n devices will slow this down but this won’t hurt so much.

Basically one for speed and one for compatibility and this is still dual band. Triple band could be another card supporting 802.11ad or 802.11y. But i think 11ad has not enough range and 11y is US-only and has no devices.


#32

Thanks you so much for your elaborate answer!

Much clearer now (ill look into it tomorrow again as it is kind of late now)!

Yet another reason to go for the Omnia; its awesome community!


#33

I must add my thanks for a very extensive and concise coverage of this topic. Most considerate and helpful!


#34

Here are two videos about MIMO.

Simple

More technical


#35

Jah; I watched those (and several others) about the concepts. Thanks!

Those explained the techniques in theory; can be applied in various ways tough. That’s where @adminX’s awesome explaining post came in! :slight_smile: What still confused me though was the following (about the rational to having two cards embedded in the Omnia):

as the WLE900VX is dualband; I thought it should be able to support both the 2.4Ghz and 5Gz frequency (tripple-chained / able to use 3 antennae). But I think that - despite it being dualband - still a second radio is needed because:

So in fact there are 2 cards: 1) to use the 2.4 Ghz freq. and 2) another to use the 5 Ghz dedicatedly / at the same time as the latter - the dual-band one - can not do both at the same time (if it were to be the only one). Am I right @adminX?


#36

Right! :+1:

Note: short posts are not allowed :frowning:


#38