WL1807MOD: WL1807MOD about Antenna Diversity for AP connection

Yasumika

Intellectual 550 points

Part Number: WL1807MOD

My customer is considering to use the WL1807MOD and they have a question about Antenna Diversity for AP connection

as follows:

---

I would like to confirm the following specifications for the WL1807MOD.

According to the specifications of WL18xx 5GHZ Antenna Diversity (file name: swaa161.pdf), antenna diversity works during scanning and connection.

Does it work when connecting to an AccessPoint (authentication, Association)?

If Yes, how do I enable it when connecting to an Access Point?

We have changed the parameters of wl18xx-conf.bin and connected the antenna to RF_ANT1 and RF_ANT2 of WL1807MOD to use the diversity function.

wl18xx.phy.high_band_component_type = 0x0a

wl18xx.phy.number_of_assembled_ant5 = 0x02

If the RF_ANT1 antenna and Access Point communicate, the connection was successful.

If the RF_ANT2 antenna communicates with the Access Point, the connection will fail.

When I checked the operation when the connection with AccessPoint failed, it recognized the Beacon packet from AccessPoint and sent the authentication packet.

However, the Access Point side did not receive the authentication packet.

After connecting to Access Point with RF_ANT1 once, data communication was possible even if I switched to the antenna of RF_ANT2.

Therefore, I thought that the diversity function was enabled during scanning and after connecting to the Access Point, and disabled while connecting to the Access Point.

The TI_SDK and wlconf F / W used are as follows.

　TI_SDK　　　　：　4.2.0.9

　wlcore F/W　：　Rev 8.9.0.1.79

AccessPoint uses hostapd and Station uses wpa_supplicant. The version is as follows.

　AccessPoint　：　 hostapd v2.5-devel

　Station　　　　　：　 wpa_supplicant v2.5-devel

----

Someone tell me, please.

Best Regards,

Y M

over 4 years ago

0 S over 4 years ago

TI__Mastermind 35795 points

Hi,

Antenna diversity on 5 GHz band is supported on WiLink8 .

Seems like you have already set diversity related parameters in the configuration file .

Can you pls test with the latest firmware and let us know the results : https://git.ti.com/cgit/wilink8-wlan/wl18xx_fw/

Can you pls provide details of how you are testing this scenario ? Are you actually disconnecting the antenna from respective antenna ports or attenuating the signal ?

Best
Saurabh

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

Thank you for your replay.

I have reported your comment and received new their comment below;

---

I replaced it with the latest F / W, but the problem was not solved.

[ 36.882152] wlcore: PHY firmware version: Rev 8.2.0.0.245

[ 37.050080] wlcore: firmware booted (Rev 8.9.0.0.86)

In our environment, the Access Point and attenuator are placed in an anechoic chamber and connected to the Station by wire.

The Attenuator of the Access Point is adjusted so that the received signal becomes -74 dBm on the Station side.

The antenna that is not connected to the AP on the Station side is terminated with 50Ω.

The Access Point is always running hostapd, waiting for a connection from the station.

The station is checking by switching the wired connection between RF_ANT1 and RF_ANT2.

We have confirmed the following contents.

(1) When RF_ANT1 of the station and AP are connected by wire and the power of the station is turned on, the connection with the Access Point is successful.

[ 118.638483] wlanA: authenticate with 88:3f:4a:db:a9:01

[ 118.650025] wlanA: send auth to 88:3f:4a:db:a9:01 (try 1/3)

[ 118.718448] wlanA: authenticated

[ 118.728860] wlanA: associate with 88:3f:4a:db:a9:01 (try 1/3)

[ 118.833483] wlanA: RX AssocResp from 88:3f:4a:db:a9:01 (capab=0x11 status=0 aid=1)

[ 118.865516] wlanA: associated

[ 118.897497] wlcore: Association completed.

(2) If you connect RF_ANT2 of station and AP by wire and turn on the power of station, the connection with Access Point will fail.

No log output.

(3) After executing (2), if you change the wired connection of the Access Point from RF_ANT2 to RF_ANT1 of the station, the connection with the Access Point will be successful.

[ 189.844807] wlanA: authenticate with 88:3f:4a:db:a9:01

[ 189.855510] wlanA: send auth to 88:3f:4a:db:a9:01 (try 1/3)

[ 189.922432] wlanA: authenticated

[ 189.936430] wlanA: associate with 88:3f:4a:db:a9:01 (try 1/3)

[ 189.950594] wlanA: RX AssocResp from 88:3f:4a:db:a9:01 (capab=0x11 status=0 aid=1)

[ 189.992966] wlanA: associated

[ 190.185458] wlcore: Association completed.

(4) After executing (3), if you change the wired connection of the Access Point from RF_ANT1 to RF_ANT2 of the station before detecting beacon lost, the connection with the Access Point will be maintained.

The connection with the Access Point was confirmed with the ping command.

# ping 172.31.22.10

PING 172.31.22.10 (172.31.22.10): 56 data bytes

64 bytes from 172.31.22.10: seq=0 ttl=64 time=2.888 ms

64 bytes from 172.31.22.10: seq=1 ttl=64 time=2.758 ms

(5) After executing (4), if you disconnect the access point from RF_ANT2, make it beacon lost, and then connect to RF_ANT2 again, the connection with the access point will fail.

[ 4655.401517] wlcore: Beacon loss detected. roles:0x1

[ 4658.486356] wlcore: Connection loss work (role_id: ).

[ 4658.494316] wlanA: Connection to AP 88:3f:4a:db:a9:01 lost

[ 4664.748638] wlanA: authenticate with 88:3f:4a:db:a9:01

[ 4664.760147] wlanA: send auth to 88:3f:4a:db:a9:01 (try 1/3)

[ 4664.946355] wlanA: send auth to 88:3f:4a:db:a9:01 (try 2/3)

[ 4665.106308] wlanA: send auth to 88:3f:4a:db:a9:01 (try 3/3)

[ 4665.256414] wlanA: authentication with 88:3f:4a:db:a9:01 timed out

From the above, I think that only RF_ANT1 can be used when connecting to AccessPoint.

----

Please advice for me.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Hi Y M,

Thank you for the details .

To clarify , in step 4 , DUT is already connected to AP , and user switches antenna to RF_ANT2 port. DUT maintains connection to AP , and is able to respond to ping requests etc ? What is the RSSI value reported by DUT ? ( command like "iw wlan0 link" can help here ). Is DUT able to communicate over RF_ANT2 port successfully in this case ?

Best

Saurabh

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

Thank you for your advice.

I have received their confirming below;

---

＞DUT is already connected to AP , and user switches antenna to RF_ANT2 port. DUT maintains connection to AP , and is able to respond to ping requests etc ?

Yes.

＞What is the RSSI value reported by DUT ? ( command like "iw wlan0 link" can help here ).

It is about -72dBm.

＞Is DUT able to communicate over RF_ANT2 port successfully in this case ?

Yes.

When RF_ANT1 of Access Point and RF_ANT1 of station are connected by wire and wpa_supplicat is executed, authentication with Access Point is successful.

When RF_ANT1 of Access Point and RF_ANT2 of station are connected by wire and wpa_supplicat is executed, authentication with Access Point fails.

Can you find out why authentication fails when you connect RF_ANT1 on the Access Point and RF_ANT2 on the station by wire?

----　

Please advice for me.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Hi,

Is -72dbm expected RSSI value ? I am asking to confirm if DUT is receiving/transmitting on RF_ANT2 port for case 4.

Do we believe antenna diversity is working ok after DUT associates with AP?

Best

Saurabh

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

Thank you for your advice.

I have received their confirming below;

---

＞Is -72dbm expected RSSI value ?

Yes.

＞ I am asking to confirm if DUT is receiving/transmitting on RF_ANT2 port for case 4.

I confirmed if DUT is receiving/transmitting on RF_ANT2 port for case 4 by checking power with RF_power_meter

＞Do we believe antenna diversity is working ok after DUT associates with AP?

Yes.

However, antenna diversity does not work before DUT associate.

---

Please advice for me.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Hi Y M,

To make sure i understand correctly , RF_ANT2 is receiving signal at -72dBm for case 4 . That's weak signal strength and I believe in this case RF_ANT2 port should receiver stronger signal compared to RF_ANT1. What is the signal strength at RF_ANT1. ?

Best,

Saurabh

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

Thank you for your advice.

I have received their confirming below;

---

>What is the signal strength at RF_ANT1. ?

In case 4, RF_ANT1 of Station has a dummy load (50Ω) connected, so RF_ANT1 has a sufficiently weak reception strength compared to RF_ANT2.

We have prepared block diagrams for case 3 to case 5 (Block_Diagram.txt).

In case 5, if you try to disconnect and reconnect to the Access Point, it will fail. However, Station is receiving beacom.

[ 4655.401517] wlcore: Beacon loss detected. roles:0x1

[ 4658.486356] wlcore: Connection loss work (role_id: ).

[ 4658.494316] wlanA: Connection to AP 88:3f:4a:db:a9:01 lost

[ 4664.748638] wlanA: authenticate with 88:3f:4a:db:a9:01

[ 4664.760147] wlanA: send auth to 88:3f:4a:db:a9:01 (try 1/3)

[ 4664.946355] wlanA: send auth to 88:3f:4a:db:a9:01 (try 2/3)

[ 4665.106308] wlanA: send auth to 88:3f:4a:db:a9:01 (try 3/3)

[ 4665.256414] wlanA: authentication with 88:3f:4a:db:a9:01 timed out

Can the Station authenticate to the Access Point with a wired connection between the Access Point's RF_ANT1 and the Station's RF_ANT2?

----

Fullscreen Block_Diagram.txt Download

case(3)

After executing (2), if you change the wired connection of the Access Point from RF_ANT2 to RF_ANT1 of the station, the connection with the Access Point will be successful. 

|         < Access Point >        |                             < Station >
 
+------  <anechoic chamber > -----+
|                                 |                              WL1807MOD
|  WL1807MOD                      |              /-------------- (RF_ANT1)
|  (RF_ANT1) ---  attenuator  --- + --- <wire> -+ 
|   (20dBm)         (-90dB)       |                dummy load -- (RF_ANT2)
+---------------------------------+                   (50��)


case(4)

After executing (3), if you change the wired connection of the Access Point from RF_ANT1 to RF_ANT2 of the station before detecting beacon lost, the connection with the Access Point will be maintained. 

|         < Access Point >        |                            < Station >
 
+------  <anechoic chamber > -----+
|                                 |                             WL1807MOD
|  WL1807MOD                      |               dummy load -- (RF_ANT1)
|  (RF_ANT1) ---  attenuator  --- + --- <wire> -+   (50��)
|   (20dBm)        (-90dB)        |              \------------- (RF_ANT2)
+---------------------------------+


case(5)

After executing (4), if you disconnect the access point from RF_ANT2, make it beacon lost, and then connect to RF_ANT2 again, the connection with the access point will fail. 


|         < Access Point >        |                            < Station >
 
+------  <anechoic chamber > -----+
|                                 |                             WL1807MOD
|  WL1807MOD                      |               dummy load -- (RF_ANT1)
|  (RF_ANT1) ---  attenuator  --- + --- <wire> -+   (50��)
|   (20dBm)        (-90dB)        |              \------------- (RF_ANT2)
+---------------------------------+

Please advice for me.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Hi,

Thanks for providing the details.

Assuming AP is transmitting at 15 dBm , 90 dBm attenuation will reduce signal strength to -75 dBm. In this case , both antennas have weak signal - weaker than 70 dBm ( which is used for antenna diversity ). Are the results different if you reduce the attenuation to -65 dBm ?

Best

Saurabh

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

Thank you for your advice.

I have received their confirming below;

---

>Are the results different if you reduce the attenuation to -65 dBm ?

No.

I checked "iw wlanA link" that the signal was -60 dBm and performed case4, but the result was the same (cannot authenticate with Access Point)

Therefore, I think the strength of RSSI is not relevant.

---

Please advice for me.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Hi Y M,

I will check with the team and get back to you .

Best

Saurabh

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

Thank you for your some confirming.

I am waiting for you checking result.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Hi Y M

Pls expect a reply in next few days.

Best

Saurabh

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

Thank you for your comment.

I am waiting for your reply.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

How about the your checking?

Please tell me your status.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Hi Y M,

We do not have an update yet.

We will keep you posted.

Best

Saurabh

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh,

Thank you for your reply.

I am waiting for your update.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Hi ,

Will keep you updated

Thank you

Saurabh

0 Vincent Rodriguez over 4 years ago in reply to S

TI__Mastermind 28285 points

Hi Y M,

can you do the following:

provide full log of commands you are using to connect to an access point.
1. I’d like to make sure you're using a standard connection procedure
run a scan before attempting to connect.
1. Diversity is done both in scans and in AP connections, so perhaps by running the scan it makes the diversity algo update to the correct antenna.
enable more debug prints from the supplicant to ensure we aren’t missing something
1. https://www.ti.com/lit/ug/swru575/swru575.pdf?ts=1623700703282&ref_url=https%253A%252F%252Fwww.google.com%252F

Thanks!

Vince

0 Yasumika over 4 years ago in reply to Vincent Rodriguez

Intellectual 550 points

Hello Vince,

Thank you for your advice.

I have forwarded advice to my customer.

Please wait their reply.

Best regards,

Y M

0 S over 4 years ago in reply to Yasumika

TI__Mastermind 35795 points

Thank you for the update

0 Yasumika over 4 years ago in reply to S

Intellectual 550 points

Hello Saurabh and Vince,

I have received their confirming below;

---

We tried running STA with active scan enabled.

Specifically, We set [passive_scan=1] in wpa_supplicant.conf

I have confirmed that anntena diversity work well with this setting.

On the other hand, anntena diversity dosen't work with setting [passive_scan=0].

From the above, anntena diversity only work well with setting [passive_scan=1], right?

We are getting the full log.

Just a moment, please.

---

Please wait their more update and advice for me.

Best regards,

Y M

0 Yasumika over 4 years ago in reply to Yasumika

Intellectual 550 points

Hello Saurabh and Vince,

I have reported comment for about their the full log.

They could not provide the full log, because of they are customizing the WiLink driver for the 11j (4.9GHz).

So, could you have some advice for their current status?

Tell me please

Best regards,

Y M

0 Vincent Rodriguez over 4 years ago in reply to Yasumika

TI__Mastermind 28285 points

Hi Yasumika,

I believe it makes sense to require the passive scan to ensure the antenna diversity functions properly. Is this solution okay with the customer?

BR,

Vince

0 Yasumika over 4 years ago in reply to Vincent Rodriguez

Intellectual 550 points

Hello Vince,

When I have reported your comment to the customer, they was convinced.

So this post has been resolved.

Saurabh and Vince,

Thank you so much for your many advice.

Regards,

Y M

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WL1807MOD: WL1807MOD about Antenna Diversity for AP connection