Hello,
This is a known limitation of the zigbee standard that state, (for some lost reasons) that the link quality has to be “very good�? to succeed on the Zigbee commissioning. But the standard, on STM32WB, can be bypassed, to remove the condition “link quality�? altogether. Saying it differently: without modifying the TX_POWER level, adding the 3 lines bellow, only at ZR side) will remove the “link quality > 3�? condition and the commissioning distance will then be of 50 meters (with free line of sight between ZC and ZR). To bypass the link quality, this code example is provided (file : Zigbee\Zigbee_OnOff_Client_Router\STM32_WPAN\App\app_zigbee.c)
….
/* Attempt to join a zigbee network */
ZbStartupConfigGetProDefaults(&config);
// printf("Solution, related to ZbNwkIfSetTxPower, no huge differences between join and application with val8 equal 1\r\n");
uint8_t val8;
val8 = 1;
status = ZbBdbSet(zigbee_app_info.zb, ZB_BDB_JoinIgnoreLqi, &val8, sizeof(val8));
// printf("val8 equal 1, and M0_AND_M4_0db : value of 50 meter for Join plus or minus 10m, then 70 meters for On OR Off\r\n");
// printf("val8 equal 1, and M0_AND_M4_minus20db : value of 6 meter for Join plus or minus 2m, then 8 meters for On of Off\r\n");
/* Set the centralized network */
APP_DBG("Network config : APP_STARTUP_CENTRALIZED_ROUTER ");
config.startupControl = zigbee_app_info.startupControl;
/* Using the default HA preconfigured Link Key */
memcpy(config.security.preconfiguredLinkKey, sec_key_ha, ZB_SEC_KEYSIZE);
config.channelList.count = 1;
config.channelList.list[0].page = 0;
config.channelList.list[0].channelMask = 1 << CHANNEL; /*Channel in use */
….
For legal reasons, the ST legal department is asking me to add this sentence:
In relation to the bypass solution written above, since not in line with the Zigbee standard, ST decline any responsibility in case using it.
NOTE: Zigbee specification paragraph for the link quality
In Zigbee specification document zigbee-specification_2017.pdf the question of LQI-“link cost�? above/bellow a certain threshold is listed. Copy paste of the main sentence here:
3.6.1.4.1 Joining a Network Through Association
For a device that is not already joined to a network, the NLME-JOIN.request primitive shall cause the NWK layer to search its neighbor table for a suitable parent device, i.e. a device for which following conditions are true:
…
• The link quality for frames received from this device is such that a link cost of at most 3 ((See NOTE2: link cost 3 code details)) is produced when calculated as described in section 3.6.3.1.
…
After this good news, I am sorry to say that we discovered a second issue related to TX_power. TX_power can be switch to 6db on a nucleo board but it doesn’t have, exactly the expected behavior.
We are working on this second issue and we hope that this second TX_power issue is not needed in your case.
This second issue related to TX_power will be solved with the M0 bin of FW 1.14.
Best Regards
