Table 2 Operation states of a gateway node with corresponding current consumptions and daily activity time

Radio transmitting

197

5/3600 x (60/T2 × 24–24/T1)

Data collecting

197

N_event × 15/3600

Data uploading

310

N_event × 15/3600

Network synchronization

331

10/3600 × 24/T1

Sleep

0.3

24 - t_{Radio transmitting} – t_{Data collecting} – t_{Data uploading} – t_{Network sync.}