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This paper considers the novel problem of deriving a Time Division Multiple Access (TDMA) link schedule for rechargeable wireless sensor networks (rWSNs). Unlike past works, it considers: (i) the energy harvesting time of nodes, (ii) a battery cycle constraint that is used to overcome so called memory effects , and (iii) battery imperfections, i.e., leakage. This paper shows analytically that the battery cycle constraint and leaking batteries lead to unscheduled links. Further, it presents a greedy heuristic that schedules links according to when their corresponding nodes have sufficient energy. Our simulations show that enforcing the battery cycle constraint increases the link schedule by up to 1.71 (0.31) times for nodes equipped with a leaking (leak-free) battery. When nodes have a leaking battery, the derived schedules are on average 1.05 times longer than the case where nodes have a leak-free battery. Finally, the battery cycle constraint reduces the number of charge/discharge cycles by up to 47.41% (45.67)% when nodes have a leak (leak-free) battery. Between leak-free and leak battery scenarios, using the former produces up to 51.46% fewer cycles than the latter.

This paper considers the problem of generating the shortest time division multiple access (TDMA) schedule for use in rechargeable wireless sensor networks (rWSNs) with heterogeneous energy arrivals rates. This novel problem considers: 1) the time required by nodes to harvest sufficient energy to transmit/receive a packet; 2) harvest-use-store (HUS) energy harvesting and usage models, and; 3) battery imperfections, i.e., leakage, storage efficiency, and capacity. This paper shows the problem at hand, called link scheduling in harvest-use-store (LSHUS), is in general NP-Complete. Furthermore, it presents a greedy heuristic, called LS-rWSN, to solve LSHUS. Our experiments show that a longer energy harvesting time (leakage rate) from 1 to 20 (0% to 4%) increases the schedule length by up to 565.82 (44.54%) slots while reducing storage efficiency from 1.0 to 0.6 lengthens the schedule by up to 62.77%. In contrast, battery capacity has an insignificant effect, i.e., enlarging the capacity by 20 times decreases the schedule length by only 6.5%.