How is theTransmit EIRP calculated for IAPs post 6.5.2.x

Aruba Employee
Q:

How is the Transmit EIRP calculated for IAPs post 6.5.2.x?



A:

Article applicable for AP 2xx and 3xx series APs.

On the older version transmit EIRP was calculated = user configured EIRP+Antenna gain

Post 6.5.2.x Transmit EIRP is calculated = user configured EIRP + Antenna gain + MIMO Gain

power gain = 10*log (#txchains) --> ( TX chain is varied across different models of the APs).

 

Example: 

AP 103,207,205,203H203R,205H & 303H - 2 Tx Chains

AP 215,225 - 3 TX Chains 

AP 315 - 2 TX chains in 2.4Ghz and 3 TX chains in 5Ghz

AP 325,335 - 4 TX chains

 

 

In general, radio will not support per chain conducted power say <0 dBm (1 mW)

Example:

Pre 6.5.2. 

If a user configured EIRP is 5 dBm then the transmit EIRP will be displayed as 5 dBm.

However, actual EIRP calculated = 5 dBm-4dBi+10*log(4)+3dBi = 10 dBm

Post 6.5.2.

In post 6.5.2. the AP will display the actual Transmit EIRP which includes the MIMO gain.

 

Following command will help to check the min transmit EIRP,

# show ap debug power-table. --> can be specified with radio 0 &1 respectively.

 

Example:

00:0b:86:ed:c5:20# show ap debug power-table 


Home Channel:                   36

Channel Width:                  20MHz

User Configured:                6.0 dBm (EIRP) User Input

                                7.2 dBm (EIRP) Effective

                                0.0  dBm (Conducted)

Min Power:                      7.2 dBm (EIRP)

                                0.0  dBm (Conducted)

Max Power:                      22.7 dBm (EIRP)

Actual Power:                   7.2 dBm (EIRP)

Antenna Gain:                   4.3  dB

                                4.25 dB (Rounded to quarter-dB)

Antenna Polarization:           Co-Polarized

Number of Active Chains:        2

Muli-Chains Power Gain:         3.0 dBm

TXBF Max Correlation Gain:      3.0 dBm

Power Limit Under 802.3af:      No

OLPC:                           On


Regulatory Limits (Conducted, dBm):

20MHz:

             Nss Ntx

CCK/DSSS      1   1    *     *     *     *     

OFDM          1   1    15.5  15.5  15.5  15.5  15.5  15.5  15.5  15.5  

HT/VHT        1   1    15.5  15.5  15.5  15.5  15.5  15.5  15.5  15.5  15.5  15.5  

CCK/DSSS      1   2    *     *     *     *     

OFDM CDD      1   2    12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  

HT/VHT CDD    1   2    12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  

HT/VHT STBC   1   2    12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  

HT/VHT SDM    2   2    12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  

HT/VHT TXBF   1   2    12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  

HT/VHT TXBF   2   2    12.5  12.5  12.5  12.5  12.5  12.5  12.5  12.5  -0.25 -0.25 



Board Limits (Conducted, dBm):

20MHz:

             Nss Ntx

CCK/DSSS      1   1    *      0.0   0.0   0.0  

OFDM          1   1    16.0  16.0  16.0  16.0  16.0  15.5  15.0  14.5  

HT/VHT        1   1    16.0  16.0  16.0  16.0  15.5  15.0  14.5  14.0  14.0  14.0  

CCK/DSSS      1   2     0.0   0.0  *      0.0  

OFDM CDD      1   2    16.0  16.0  16.0  16.0  16.0  15.5  15.0  14.5  

HT/VHT CDD    1   2    16.0  16.0  16.0  16.0  15.5  15.0  14.5  14.0  14.0  14.0  

HT/VHT STBC   1   2    16.0  16.0  16.0  16.0  15.5  15.0  14.5  14.0  14.0  14.0  

HT/VHT SDM    2   2    16.0  16.0  16.0  16.0  15.5  15.0  14.5  14.0  14.0  14.0  

HT/VHT TXBF   1   2    16.0  16.0  16.0  16.0  15.5  15.0  14.5  14.0  14.0  14.0  

HT/VHT TXBF   2   2    16.0  16.0  16.0  16.0  15.5  15.0  14.5  14.0  *     *     



Combined Target Powers (Conducted, dBm):

20MHz:

             Nss Ntx

CCK/DSSS      1   1    *     *     *     *     

OFDM          1   1     0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0  

HT/VHT        1   1     0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0  

CCK/DSSS      1   2    *     *     *     *     

OFDM CDD      1   2     0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0  

HT/VHT CDD    1   2     0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0  

HT/VHT STBC   1   2     0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0  

HT/VHT SDM    2   2     0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0  

HT/VHT TXBF   1   2     0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0  

HT/VHT TXBF   2   2     0.0   0.0   0.0   0.0   0.0   0.0   0.0   0.0  *     *     



Actual Transmit Powers (EIRP, dBm):

20MHz:

             Nss Ntx

CCK/DSSS      1   1    *     *     *     *     

OFDM          1   1     4.25  4.25  4.25  4.25  4.25  4.25  4.25  4.25 

HT/VHT        1   1     4.25  4.25  4.25  4.25  4.25  4.25  4.25  4.25  4.25  4.25 

CCK/DSSS      1   2    *     *     *     *     

OFDM CDD      1   2     7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25 

HT/VHT CDD    1   2     7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25 

HT/VHT STBC   1   2     7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25 

HT/VHT SDM    2   2     7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25 

HT/VHT TXBF   1   2    10.25 10.25 10.25 10.25 10.25 10.25 10.25 10.25 10.25 10.25 

HT/VHT TXBF   2   2     7.25  7.25  7.25  7.25  7.25  7.25  7.25  7.25 *     *     



Note:

  Nss: Number of Spatial Streams

  Ntx: Number of Transmit Chains

  TXBF: Transmit Beamforming

  OLPC: Open Loop Power Control

  Effective User Configured (EIRP) = MAX(User Input (EIRP), Min Power (EIRP))

  User Configured (Conducted) Power is maxed at 31.75 dBm

  Board Limits = the original Board Limits - Transmit Power Back-off

  Combined Target Powers = MIN(Regulatory Limits, Board Limits, User Configured (Conducted),

                               Power Limit Under 802.3af)

  Actual Transmit Powers = Combined Target Powers + Muli-Chains Power Gain + Antenna Gain

                           + TXBF Correlation Gain

 

Version history
Revision #:
2 of 2
Last update:
a week ago
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