“…7 The first type is hybrid transmission, such as Wang and colleagues, 8,9 in which sensor nodes have two data transmitting modes: (1) single-hop (SH) transmission, in which every node sends data to the sink by an one-hop way and does not need any relay node; and (2) multiple-hop (MH) transmission, in which most packets are sent to the destination by a relay way, that is, at least two hops of data delivery. The second type is power control, such as Zhang et al, 10 Kavitha et al, 11 and Lai et al, 12 in which sensor nodes with less data delivery tasks use shorter communication range while the reverse is performed for those with more data delivery tasks. The third type is multifactor routing, such as Liu et al, 13 Peng et al, 14 and Qin et al, 15 in which data delivery paths are determined according to some key factors, for example, the remaining energy of nodes, the distance between two nodes, and the density distribution of nodes.…”