Issue link: https://read.uberflip.com/i/1428395
LoRaWAN ® L2 1.0.4 Specification © 2020 LoRa Alliance ® Page 83 of 90 The authors reserve the right to change specifications without notice. If a Class A end-device receives a frame where FPending is set, it is recommended that the 2487 end-device transmit an uplink data frame as soon as reasonably possible, which would allow 2488 the end-device to receive more information from the Network. However, the precise timing of 2489 the uplink transmission is not specified and is application-dependent. 2490 Note: The FPending bit is independent of the frame-acknowledgment 2491 mechanism. 2492 2493 2494 2495 Figure 11: Downlink timing diagram for frame-pending frames, example 1 2496 2497 In this example, the Network Server has two data frames to transmit to the end-device. The 2498 frame exchange is initiated by the end-device via a normal unconfirmed uplink data frame. 2499 The Network Server uses the first receive window to transmit the Data0 downlink data frame 2500 with the bit FPending set, as an unconfirmed downlink data frame. The end-device, in 2501 response to the FPending indication, transmits quickly an empty unconfirmed data frame. 2502 Exactly RECEIVE_DELAY1 seconds later, the Network Server transmits the second downlink 2503 data frame Data1, using a confirmed downlink data frame but with the FPending bit 2504 cleared. The end-device transmits an uplink data frame with the ACK bit set to acknowledge 2505 the confirmed downlink data frame Data1. 2506 2507 2508 Figure 12: Downlink timing diagram for frame-pending frames, example 2 2509 2510