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I have designed a 5 point low power wireless network using 868 MHz modules and want to test the wireless connection performance indoor. The points are going to be fixed to the wall and placed above each other with each one located in a separate floor (so there are 5 floors). My questions are:

  1. The parameters that I care about are speed, signal strength and error rate. How do professional companies evaluate the performance of such a wireless network? How do they find the maximum limitations of a wireless network? Are there any other important parameters?

  2. Each PCB has a horizontal antenna and for the time being I have the PCBs without boxes so I can't mount the PCBs to the wall. I am thinking about just laying the PCBs on the ground. I don't like the fact that the antennas are going to be close and parallel to the ground to get the test done. Is this an acceptable close enough approach? What would professional companies do to test the wireless PCBs before manufacturing the boxes? Would they settle for doing the tests on a bench?

Thank you in advance.

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  • \$\begingroup\$ The question about antennas was clear, but what other part(s) of the whole system do you want to test? Do you want to re-characterize the modules to check manufacturer claims? Do you want to test a custom protocol you've developed? Do you want to check if what you've build around modules has an impact on performance? Do you want to characterize radio propagation and interference on a specific site? To understand "performance", you have to understand the influence and interaction of the different parts of the whole system and isolate their contributions. \$\endgroup\$ – Sylvain May 21 '17 at 14:16
  • \$\begingroup\$ @Sylvain The parameters I am interested in the most are speed, signal strength and error rate. For sure there is a protocol (to be tested) that allows the wireless points to talk with each other. My main goal is to test this wireless network under real circumstances. (BTW this is a multi-hop wireless network). \$\endgroup\$ – Macit May 21 '17 at 15:01
  • \$\begingroup\$ look for "wireless network testbed" and what academics are doing. Don't forget to measure power, for a low-power wireless network this is a key characteristics. \$\endgroup\$ – Sylvain May 21 '17 at 15:26
  • \$\begingroup\$ When you add boxes, expect a major drop in performance if the boxes happen to be electrically conductive (for example, metal). \$\endgroup\$ – user6030 May 26 '17 at 1:21
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I've seen a few wireless testbeds for 2.4 GHz (802.15.4) networks, including multi-hop links, deployed in both academic and industrial (though R&D) environments. None of these was for certification of link performance, but more to generally assess the feasibility of the given architecture with the to-be-tested hardware and protocol.

The networks were deployed trying to replicate a typical 'sound' installation therefore with a backbone running through central spaces (like corridors) and with line of sight between the nodes, and several other nodes scattered around in the rooms.

If you want to test the maximum reach of the nodes, then you're better served by going to an open space and putting the nodes within line of sight. Even better if you can raise them as much as possible over the ground, which may be a source of reflection and/or attenuation. If instead you want to experiment real-world performance in the indoor setting you describe, you can try the above approach, plus you can try using two (or more) nodes in two separate rooms with different degrees of separation, like drywall, stone wall, glass and whatever you can come up with.

Also note that with higher-level protocols, you may have some trouble checking for errors, as the protocol will try to auto-correct and you will just be able to measure the effective speed or a calculated metric of signal strength.

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