Setting TXANT / ANTDIV antenna always returns success

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Anonymous
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Hi,

We are using Broadcom 43362 module. We have only one Internal Antenna on module and no Auxiliary antenna is connected to module.

We are initializing the Wi-Fi 43362 module successfully, then we are setting Antenna to Antenna_1, Antenna_2 and Antenna_Auto using wwd_wifi_select_antenna() API. But in case of setting Antenna_2, even though there is no auxiliary antenna connected to module wwd_wifi_select_antenna() API returns success and Wi-Fi module successfully get provisioned as STATION mode and also received IP address to Wi-Fi module.

We have following question on this:

1. Our expectation is that, if there is no Auxiliary Antenna, then setting Antenna_2 should failed, shouldn't it?

2. We are setting Antenna after initilization of Wi-Fi module using wwd_wifi_select_antenna(), do we have to any configuration before setting Antenna value?

Please point us any test application or Document if any.

Thanks & Regards,

Santosh Itkare

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Anonymous
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Any inputs on this?

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Anonymous
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Hi Santosh,

The command to select the antenna controls an external switch (if fitted), there is no feedback path to confirm the switch setting so issuing the command will always succeed.

Can you advise which module you are using here.

Regards

Dave

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Anonymous
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Hi Dave,

Thanks for reply.

We are using Murata 43362 and Murata 4343W module.

Setting Antenna will always success, no issue but when Antenna_2(Auxiliary antenna) is set and that antenna is actually not connected to Wi-Fi Module, then all TX/RX operation should failed and Wi-Fi module should not able to Scan the available Access Point(when configured in Station mode) OR

When configured as AP, other device should not be able to scan this AP, correct?

In our case, Wi-Fi module able to scan the available Access point(in Station mode) OR

When configured as AP, other device able to scan this AP without auxiliary antenna.

In short, when there is no Auxiliary Antenna and if we set Antenna value to Antenna_2 then all TX/RX operation should failed which is not happening in our case.

Please correct me if my understanding is wrong.

Thanks & Regards,

Santosh Itkare

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Anonymous
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Hi Santosh,

Have you checked RF power (RSSI on peer device) when Antenna_2 is selected?

Even if antenna is not connected, (weak) RF is transmitted.

Anonymous
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Hello Santosh,

This is not always the case due to the very high sensitivity of the wlan radio.   If for example, you configure the radio to use the auxilliary antenna but do not physically fit the aux antenna, then the radio may still be able to connect to the AP, but the signal strength will be much reduced, say 20-30dB lower.    If the radio and the AP are relatively close then it will still be able to connect.

please check the rssi signal levels to confirm.

Regards

Dave

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Anonymous
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Hi david_armour

We collected the RSSI value when Wi-Fi module is configured in STATION mode, but we did not find any difference in RSSI value with Main antenna(physically present on module) and Auxiliary Antenna(physically not connected). Those are almost same.

We also tried configuring the Wi-Fi module as Access Point and check the RSSI on peer device, here also we found almost same signal strength.

We are using Murata 43362-SN8000UFL and Murata 4343W-Type 1DX module.

As per SN8000UFL schematic it shows, there are two antennas present on module, one is Internal and second we need to connect it using UFL connector(TRF-1002/W1049B050/W3525B100 as recommended by Murata), which we have not connected, still we are getting almost same RSSI value, why?

Also as per Murata 4343W-Type 1DX schematic, there is only one antenna present. If I set Antenna_2 in this Wi-Fi module, looks like it is using Antenna_1 only?

Thanks & Regards,

Santosh Itkare

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See attached. Posted per request from david_armour

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Anonymous
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Hi santosh@k2-inc.com

There will be no difference whether you set the radio into AP mode or STA mode, it comes down to the control of the antenna port only.

For the 1DX module, what you report is correct.  There is a single rf path and therefore no antenna switch to control.   On the SN8000ULF there is a SPDT switch in the rf path which should respond to the commands you are sending.

I don't have a muRata module readily to hand here so have run through the exercise using a Cypress eval board and using the mfg_test application.   The instructions are attached so please run through this process using your hardware to confirm you are able to control the antennas as expected here and understand the process.

Regards

Dave

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Anonymous
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Hi Dave,

It seems that command is also doing IOCTL to set the antenna, we are also doing IOCTL by calling wwd_wifi_select_antenna(). I don’t think it will make any difference but I will try your solution and let you know my observation.

Thanks & Regards,

Santosh Itkare

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Anonymous
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Hi Dave,

Sorry but previously we were using SN8000 module and we do not have connector to connect Antenna_2 to SN8000. As mentioned earlier, we collected the RSSI value with selecting Antenna_2 but did not connect it physically. In this case we got RSSI value same as we have selected Antenna_1(looks like Wi-Fi module is using Antenna_1 as Antenna_2 is not present or having very low signal strength).

Now we tried another SN8000UFL module on which Main Antenna is not present. We collected the RSSI value with and without auxiliary antenna as shown in below table:

Antenna Selected

Antenna_2 is not Connected

Antenna_2 is Connected

Access Point

WICED_ANTENNA_1

AP1

-67

-56

-51

-18

-28

-28

AP2

Not Visible

Not Visible

Not Visible

-65

-73

-62

WICED_ANTENNA_2

AP1

-58

-59

-55

-21

-29

-7

AP2

Not Visible

Not Visible

Not Visible

-63

-63

-65

Based on result, it looks like when we physically connected Antenna_2 but selected Antenna_1(marked in Red), we are getting almost same RSSI values as we have connected and selected the Antenna_2(marked in Green). Here is looks like Wi-Fi module is using Antenna_2 even if we have selected Antenna_1 for RX/TX operation(due to Antenna_1 unavailability), Will you please confirm the functional behavior of Wi-Fi firmware, how does it work when selected antenna is not present, does it uses Antenna with high signal strength(I means to say Does is apply Auto selection method explicitly when selected antenna not present/connected).

Thanks & Regards,

Santosh Itkare

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Anonymous
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Hi david_armour

CC: ghouse

Here is details of testing using SN8000 module where Main Antenna is present but we do not have any connector to connect the Auxiliary antenna so could not connect any Auxiliary Antenna.

Following table shows the RSSI values we collected for APs(AP1 is 4 feet away and AP2 is 15 feet away from SN8000 module) with Main and Auxiliary antenna selection.

Antenna Selected

Auxiliary Antenna not connected

Iteration-1     Iteration-2    Iteration-3

Access Point

Main Antenna

AP1

-33

-25

-25

AP2

-63

-62

-63

Auxiliary Antenna

AP1

-23

-23

-22

AP2

-63

-60

-58

AUTO

AP1

-21

-11

-23

AP2

-65

-59

-62

As shown in table, collected RSSI values using Main Antenna OR Auxiliary Antenna are same as result of Auto selection,  looks like it is always doing Auto selection, no effect of selecting Antenna. Again the same question, really like to know the behavior of Wi-Fi firmware, how does it work when selected antenna is not present, does it uses Antenna with high signal strength(i.e. is it doing Auto selection?)

Please let us know if we are missing anything or doing testing in wrong way.

As mentioned earlier, we do not have Wi-Fi module with Both Antenna(or provision to connect both the Antennas), its a kind request to you to please suggest proper test procedure for Antenna Diversity testing specifically for SN8000 and SN8000UFL modules(as you shared pdf for cypress eval board ) so that we can try that out here.

Thanks & Regards,

Santosh Itkare

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Anonymous
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Hi,

Any updates on this. Its kind request to at least share Test procedure for Antenna Diversity testing specifically for SN8000 and SN8000UFL modules.

Thanks & Regards,

Santosh Itkare

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Anonymous
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Hi david_armour

Will you go through the updates I posted on this thread and help me to resolve the issue.

I would like to get at least Test procedure doc for Antenna Diversity testing specifically for SN8000 and SN8000UFL modules.

Thanks & Regards,

Santosh Itkare

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Anonymous
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Hi Santosh,

I have discussed this with the muRata team and they have agreed to run through the process using a sn8000 module and to update you on the steps.

Regards

Dave

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Anonymous
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Hi Dave,

Thanks for response. Just for your information we are using Wiced 3.5.2.

Thanks & Regards,

Santosh Itkare

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Anonymous
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Hi Dave,

Any updates on this?

Thanks & Regards,

Santosh Itkare

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Anonymous
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Hi Santosh,

This is currently with muRata to replicate but I will contact them to check for an update.

Regards

Dave

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Anonymous
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Hi Santosh,

I've received feedback from muRata engineering that they followed the same process I outlined in my document and confirm they see the control pins on the module switching as expected to control the antenna port on a SN8000 module.

Regards

Dave

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