topic Re: Measurement for Voice Design (BPDG Voice) in Wireless Questions and Best Practices

Measurement for Voice Design (BPDG Voice)

rsc_at — Wed, 14 Nov 2018 20:18:14 GMT

Hi,

i have to plan a small "Voice Design" with Ruckus and Ascom i62.
Because of the weaker Signal Strength on the phone, i have to consider the difference to my measurement tool. The Vendor recommends -65dbm for the Phone and the offset to my Wifi-Dongle is about 8db. Whats the best practice?

- A Measurement with my tool (Airmagnet) to -65dbm (in view of my stick) or
- A Measurement to -57dbm to ensure, that the phone gets -65dbm in real?

Thank you for your answers!
Kindly Regards
Ralf

Re: Measurement for Voice Design (BPDG Voice)

alexey_isakov — Thu, 15 Nov 2018 06:35:29 GMT

So, first: there is a principial differense btw dB & dBm. dB is a relative admeasurement. dBm is an absolut value of energy(power) which is measuring also in, e.g., W (watt). U shouldnt mix these values.
On my opinion & practice (in other radio PDAs but similar) there is no big difference btw levels -57&-65 dBm. There are a lot of another factors strongly affected on the radiolink, such us, e.g., sensitiveness of radioreceiver of AP in these channel, or quantity of clients & many others.

Re: Measurement for Voice Design (BPDG Voice)

rsc_at — Thu, 15 Nov 2018 07:27:28 GMT

for sure, it was a mistake. The difference between my Wifi-Dongle and the Phone is about 8dbm. In the first option, if i take a measurement with my survey tool and point to -65dbm, the Phone will get maybe -73dbm. Ruckus recommends in the "Best Practices Design Guide for Voice" -65dbm and also a Measurement with the Phone/Handheld (Chapter Signal Strength).

Re: Measurement for Voice Design (BPDG Voice)

alexey_isakov — Thu, 15 Nov 2018 07:53:03 GMT

As I understand it doesnt matter what kind of traffic you transmitting in wi-fi. Radio lelel here is like a Layers 1 and 2 of OSI model and voice (UDP) traffic or video or other use this level as a transport. So I want to say that if radiolink is UP & sufficient any your traffic will be transmitted whithout losses.
Now it s hard to say will your pairs works good or not. As I sad there are many others factors fluence on it.
E.g. in 2Gh (802.11 b/g/n) such a level may be not enough but in 5Gh(802.11 a/n/ac) it is rather sufficient.
As an example in 4G cellular networks -95...-85 dBm is a limit of working levels, links are working but in -105...-95 dBm are not warranted working levels (it works but unstable). So
the frequencies of such a cellular networks are approximately the same with WiFi and those physical characteristics of radoilinks will be approximately the same too.