Wireless Access

Dear community,

I'm doing my project in which I try to estimate the distance between two APs using their RSSI. 

I use the simplified log-distance path loss distance model:

RSS(d)=RSS0(d0)−10nlog10(d/d0)

Which, the parameters I need to collect/verify are:

• $RSS(d{)}^{}$ is the power received at distance d.
• $\mathrm{RSS0(d0)}$ is the reference power at distance d0 = 1m.
• n: Path-loss exponent in the indoor building.

Assume that my system is using all APs with the same Aruba AP interface.
So in this case, do you think I need to consider the Tx power of each AP, as it might affect RSS0 value? And how do I get and change the tx power of an AP using the command-line in showcommand API? 

Also, if someone have any comment related to the other parameters (n for example), please give me advice. Thanks a lot!

Other than distance, RSSI will depend on AP power setting, channel, antenna gain (in that particular 3D direction), physical environment, etc.
There will be significant (calibration) variations from AP to AP as well, and the value of "n" may not be constant in the coverage area.
Unless you accurately measure the reference RSSI(d0) level, this all becomes quite inaccurate and variable.
Original Message:
Sent: Jan 09, 2023 06:39 AM
From: Nam Nguyen
Subject: Estimate the distance between AP and AP using RSSI values

Dear community,

I'm doing my project in which I try to estimate the distance between two APs using their RSSI.

I use the simplified log-distance path loss distance model:

RSS(d)=RSS0(d0)−10nlog10(d/d0)

Which, the parameters I need to collect/verify are:

• $RSS(d{)}^{}$ is the power received at distance d.
• $\mathrm{RSS0(d0)}$ is the reference power at distance d0 = 1m.
• n: Path-loss exponent in the indoor building.

Assume that my system is using all APs with the same Aruba AP interface.
So in this case, do you think I need to consider the Tx power of each AP, as it might affect RSS0 value? And how do I get and change the tx power of an AP using the command-line in showcommand API?

Also, if someone have any comment related to the other parameters (n for example), please give me advice. Thanks a lot!

Thank you for the reply. 

That's true, RSSI depends on several factors (as you mentioned above), also the AP interface itself. Therefore it is very challenging to measure a reference RSSI(d0) as well.

In this case, maybe I will just take the RSSI value measured from an Aruba AP at the distance = 1m as a reference.

Do you or anyone possibly know some helpful command lines to check the tx power setting or any RSSI-related parameters from an AP?

Thank you very much!





Original Message:
Sent: Jan 09, 2023 12:59 PM
From: Onno Harms
Subject: Estimate the distance between AP and AP using RSSI values

Other than distance, RSSI will depend on AP power setting, channel, antenna gain (in that particular 3D direction), physical environment, etc.
There will be significant (calibration) variations from AP to AP as well, and the value of "n" may not be constant in the coverage area.
Unless you accurately measure the reference RSSI(d0) level, this all becomes quite inaccurate and variable.
Original Message:
Sent: Jan 09, 2023 06:39 AM
From: Nam Nguyen
Subject: Estimate the distance between AP and AP using RSSI values

Dear community,

I'm doing my project in which I try to estimate the distance between two APs using their RSSI.

I use the simplified log-distance path loss distance model:

RSS(d)=RSS0(d0)−10nlog10(d/d0)

Which, the parameters I need to collect/verify are:

• $RSS(d{)}^{}$ is the power received at distance d.
• $\mathrm{RSS0(d0)}$ is the reference power at distance d0 = 1m.
• n: Path-loss exponent in the indoor building.

Assume that my system is using all APs with the same Aruba AP interface.
So in this case, do you think I need to consider the Tx power of each AP, as it might affect RSS0 value? And how do I get and change the tx power of an AP using the command-line in showcommand API?

Also, if someone have any comment related to the other parameters (n for example), please give me advice. Thanks a lot!

You can use the "show ap active" command to see Effective Isotropic Radiated Power (EIRP) of each AP.
Here's a couple blog posts explaining EIRP and why Aruba chose that:
What is EIRP and how is it calculated
Let's Talk Transmit Power. Let's Talk EIRP

Original Message:
Sent: Jan 10, 2023 05:28 AM
From: Nam Nguyen
Subject: Estimate the distance between AP and AP using RSSI values

Thank you for the reply.

That's true, RSSI depends on several factors (as you mentioned above), also the AP interface itself. Therefore it is very challenging to measure a reference RSSI(d0) as well.

In this case, maybe I will just take the RSSI value measured from an Aruba AP at the distance = 1m as a reference.

Do you or anyone possibly know some helpful command lines to check the tx power setting or any RSSI-related parameters from an AP?

Thank you very much!





Original Message:
Sent: Jan 09, 2023 12:59 PM
From: Onno Harms
Subject: Estimate the distance between AP and AP using RSSI values

Other than distance, RSSI will depend on AP power setting, channel, antenna gain (in that particular 3D direction), physical environment, etc.
There will be significant (calibration) variations from AP to AP as well, and the value of "n" may not be constant in the coverage area.
Unless you accurately measure the reference RSSI(d0) level, this all becomes quite inaccurate and variable.
Original Message:
Sent: Jan 09, 2023 06:39 AM
From: Nam Nguyen
Subject: Estimate the distance between AP and AP using RSSI values

Dear community,

I'm doing my project in which I try to estimate the distance between two APs using their RSSI.

I use the simplified log-distance path loss distance model:

RSS(d)=RSS0(d0)−10nlog10(d/d0)

Which, the parameters I need to collect/verify are:

• $RSS(d{)}^{}$ is the power received at distance d.
• $\mathrm{RSS0(d0)}$ is the reference power at distance d0 = 1m.
• n: Path-loss exponent in the indoor building.

Assume that my system is using all APs with the same Aruba AP interface.
So in this case, do you think I need to consider the Tx power of each AP, as it might affect RSS0 value? And how do I get and change the tx power of an AP using the command-line in showcommand API?

Also, if someone have any comment related to the other parameters (n for example), please give me advice. Thanks a lot!

Thank you for your reply! It is helpful.

I will try to read the materials and come up with the appropriate solutions

Original Message:
Sent: Jan 11, 2023 11:21 AM
From: dbaldonado
Subject: Estimate the distance between AP and AP using RSSI values

You can use the "show ap active" command to see Effective Isotropic Radiated Power (EIRP) of each AP.
Here's a couple blog posts explaining EIRP and why Aruba chose that:
What is EIRP and how is it calculated
Let's Talk Transmit Power. Let's Talk EIRP

Original Message:
Sent: Jan 10, 2023 05:28 AM
From: Nam Nguyen
Subject: Estimate the distance between AP and AP using RSSI values

Thank you for the reply.

That's true, RSSI depends on several factors (as you mentioned above), also the AP interface itself. Therefore it is very challenging to measure a reference RSSI(d0) as well.

In this case, maybe I will just take the RSSI value measured from an Aruba AP at the distance = 1m as a reference.

Do you or anyone possibly know some helpful command lines to check the tx power setting or any RSSI-related parameters from an AP?

Thank you very much!





Original Message:
Sent: Jan 09, 2023 12:59 PM
From: Onno Harms
Subject: Estimate the distance between AP and AP using RSSI values

Other than distance, RSSI will depend on AP power setting, channel, antenna gain (in that particular 3D direction), physical environment, etc.
There will be significant (calibration) variations from AP to AP as well, and the value of "n" may not be constant in the coverage area.
Unless you accurately measure the reference RSSI(d0) level, this all becomes quite inaccurate and variable.
Original Message:
Sent: Jan 09, 2023 06:39 AM
From: Nam Nguyen
Subject: Estimate the distance between AP and AP using RSSI values

Dear community,

I'm doing my project in which I try to estimate the distance between two APs using their RSSI.

I use the simplified log-distance path loss distance model:

RSS(d)=RSS0(d0)−10nlog10(d/d0)

Which, the parameters I need to collect/verify are:

• $RSS(d{)}^{}$ is the power received at distance d.
• $\mathrm{RSS0(d0)}$ is the reference power at distance d0 = 1m.
• n: Path-loss exponent in the indoor building.

Assume that my system is using all APs with the same Aruba AP interface.
So in this case, do you think I need to consider the Tx power of each AP, as it might affect RSS0 value? And how do I get and change the tx power of an AP using the command-line in showcommand API?

Also, if someone have any comment related to the other parameters (n for example), please give me advice. Thanks a lot!