Doubt about access point data sheets (rx sensitivity)

[mnkojima]

Hello

I have a doubt about access point data sheets, more specifically about rx sensitivity.

Using as example AP 1540 Series data sheet: for 802.11g and data rate 54 Mbps, the informed rx sensitivity is  -79 dBm. Does that mean that, at the floor level, where the AP delivers coverage of -79 dBm, the wireless client will be able to reach data rates of 54 Mbps?

thank you

Marcos

[patoberli · Accepted solution]

Based on my understanding it's exactly the opposite. The client sends the signal and the AP hears it with -79 dBm or stronger and reaches 54 Mbit/s. 

[mnkojima]

Thank you!

[Rasika Nayanajith · Accepted solution]

Hi Marcos,

Pls, see the below link about what is Rx Sensitivity. As it talks about min signal strength that it can detect WiFi signal for a given modulation. If 11g/54Mbps (OFDM, 64-QAM) require -79dBm means AP needs to hear the signal -79dBm in order to demodulate 64-QAM (or 54Mbps) modulated OFDM signal.

https://www.everythingrf.com/community/what-is-receiver-sensitivity 

Receiver sensitivity is a measure of the minimum signal strength that a receiver can detect. It tells us the weakest signal that a receiver will be able to identify and process. Receiver sensitivity is expressed in dBm. Since it represents how faint an input signal can be to be successfully received by the receiver, the lower the power level of the signal, the better. So for example a receiver sensitivity of -90 dBm is better than -80 dBm i.e this means that the -90 dBm receiver is more sensitive and can interpret lower power signals.

The typical range for receiver sensitivity of various RF modules is from -50 to -100 dBm. Different standards and technologies have different requirements for receiver sensitivity.Receiver Sensitivity Requirements for modules:

Bluetooth: -70 dBm to -100 dBm
Wi-Fi: -40 dBm to -80 dBm
Cellular: up to -120 dBm
LoRa: up to -130 dBm
GNSS: -140 to -165 dBm
ZigBee: -85 to -92 dBm

HTH

Rasika

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[mnkojima]

Thank you Rasika!