Issue link: https://read.uberflip.com/i/1507762
Enabling CSMA for LoRaWAN TR013-1.0.0 ©2023 LoRa Alliance ® Page 17 of 18 The authors reserve the right to change specifications without notice. APPENDIX 2: CAD ENERGY OVERHEAD 433 434 CSMA introduces additional energy overhead for each transmission effort. In this section, a 435 comparison between the CSMA energy footprint against that required for average 436 transmission is made for three different SFs under three different transmission power levels. 437 The results indicate that the addition of CSMA adds energy overhead of less than 1.5% for a 438 30-byte frame. 439 440 The CSMA energy footprint originates from two key phases, the DIFS phase and the BO 441 phase. For the sake of simplicity, the overhead computation assumes that the end- 442 device performs six CADs during both phases per frame, which is approximate and may 443 vary based on network contention and the type of CSMA used. In order to compute the 444 energy overhead, key choices related to radio type, transmission power, SF, and CAD 445 configuration need to be made. These choices are summarized below and in Table 3. 446 447 Frame size: 30 bytes (payload + LoRaWAN headers) 448 LoRa Radio: SX1262 449 Band: 868/915 MHz 450 451 SX1262 CAD Configuration: 452 453 SF CAD Setting Energy(nAh) cadDetMin cadDetPeak cadSymbolNum SF7 10 22 2 symbols 2.84 SF9 10 23 2 symbols 11.7 SF12 10 28 2 symbols 64.59 Table 3: SX1262 CAD energy consumption 454 Table 4 presents the transmission characteristics of the SX1262 radio under three different 455 power levels where Table 5 summarizes the CAD energy overhead for those power levels 456 for SF7, SF9, and SF12 from [SX1261/2]. 457 458 SX1262 Setting Tx Current (mA) Tx Current @14 dBm 45 mA Tx Current @17 dBm 58 mA Tx Current @22 dBm 84 mA Table 4: Transmission characteristics of SX1262 under (868/915 MHz) band 459 460