IW612 reconnectable distance

[MKobayashi]

I would like to solve the problem that there is a huge difference between the communication distance and the connection distance with IW612's classic communication (SPP).

I measured the connection and communication distance using classic communication.
It was possible to reconnection up to about 480m. This assumes that a connection can be established within 40 seconds, including retries.

SPP transmission and reception was possible over 900m. This number is the limit of the measurement location.

This question is a continuation of

https://community.nxp.com/t5/Wireless-Connectivity/IW612-long-distance-connection/td-p/1846576

FW version:IW612---18.99.2.p66.20-MM6X18437.p10-(FP92)
Kernel version:5.15.60

Best regards,

[Christine_Li]

Hi, @MKobayashi 

Thanks for creating a new thread to post your question.

May I ask where do you get this information: SPP transmission and reception was possible over 900m?

I checked the SPP specification V1.2 (Serial Port Profile 1.2), it doesn't mention this information.

Best regards,

Christine.

[MKobayashi]

Hello. @Christine_Li 

I get the following response with HCI_CMD_READ_BT_CAL_DATA command.

hcitool -i hci0 cmd 0x3f 0x0062 0x37
< HCI Command: ogf 0x3f, ocf 0x0062, plen 1
37
> HCI Event: 0x0e plen 33
01 62 FC 00 01 37 13 1C 00 00 00 00 00 01 75 04 03 28 00 00
00 C0 C6 2D 00 68 C8 9F EB 1D 6C F0 00

Initial TX Power (dBm) seems to be 4dBm.
I think this value may be used for connection processing.
Is there a way to change Initial TX Power?

Best regards,

[MKobayashi]

Hello. @Christine_Li 

I am conducting a communication test between the IW612 and an old 15dBm tx power bluetooth to test the range.
Connection and communication can be performed normally at 900m between Bluetooth devices with a 15dBm output.

The communication distance of class 1 Bluetooth is said to be 100m, but if the conditions are good, it is actually possible to communicate over 1km.
The reach distance is determined by S/N. Therefore, the distance of 900m is just a guideline.
The short connection distance means that the tx power when connected to IW612 is low. There needs to be a way to improve this.

Best regards,

[Christine_Li]

Hi, @MKobayashi 

Thanks for your reply.

Yes, we have HCI commands to change the default TX power value when BT is in RF test mode.

Please refer to our https://www.nxp.com/docs/en/application-note/AN14114.pdf 

Part: 3.1.4 Set the transmit test parameters on page 28.

We also give an example as below:

Example of command to the transmit test with the following parameters:
• TX Frequency: 2403 MHz
• Test Scenario: 0-pattern
• Hopping Mode: Fixed Frequency
• Packet Type: DM1
• TX power: 4 dBm

hcitool -i hci0 cmd 0x3F 0x0019 0x80 0x80 0x80 0x80 0x01 0x00 0x01 0x01 0x0D 0x03 0x0F 0x00 0x00 0x00 0x00 0x00 0x00 0x04

Command output example:

< HCI Command: ogf 0x3f, ocf 0x0019, plen 18
80 80 80 80 01 00 01 01 0D 03 0F 00 00 00 00 00 00 04
> HCI Event: 0x0e plen 4 01 19 FC 00

Please have a try on your side whether it is useful for you.

And also, May I know you are using a BT module or your own designed board with our IW612 chipset?

If still have problem, can you please help to provide your test results and related logs(dmesg log + snoop log)?

How to capture snoop log:

btmon -w failed_snoop.log &

Best regards,

Christine.

[Christine_Li]

Hi, @MKobayashi 

I checked your previous post and found that you are using a u-blox module: M2-MAYA-W2(IW612).

So for your information, my previous comment is used for RF test mode. When you test it with RF test equipment you can change TX power in this way. If you do not use RF test equipment, the TX power changed result will not valid. So if you want to change the TX power in calibration data, you need to use labtool to change. But for different class we have different maximum TX power, below info is for your reference:

Bluetooth TX power class	Configuration parameter
Class 1 (up to 20 dBm)	ForceClass2Op=0 Class1OpSupport=1
Class 1.5 (up to 13 dBm)	ForceClass2Op=0 Class1OpSupport=0
Class 2 (up to 4 dBm)	ForceClass2Op=1 Class1OpSupport=0

Please firstly to confirm which Class are you using.

And about how to change tx power for calibration data, you can refer to:Calibration Structure for AW611, IW611, and IW612 - Application note (confidential)

Best regards,

Christine.

[Christine_Li]

Hi, @MKobayashi 

Anything else I can do for you on this case?

Best regards,

Christine.