A Software-Defined Surveillance System With Energy Harvesting: Design and Performance Optimization

Energy Efficient Cooperative Computation Algorithm in Energy Harvesting Internet of Things

“…To obtain the optimal offloading strategy, we formulate a CMDP model with five elements. (Since the CMDP model that is a mathematical framework to model decision-making when outcomes need to be constrained, and they are partially random and under the control of the decision maker [27], it is suitable to construct the optimal offloading decision table. ): (1) decision epoch; (2) state; (3) action; (4) transition probability; and (5) cost and constraint functions.…”

“…Therefore, for the chosen action A, the transition probability from the current state of IoT device i, (10) We assume that the inter-task occurrence time of IoT device i follows an exponential distribution with mean 1/λ i . Then, the probability that the task occurs in IoT device i during a decision epoch can be calculated as λ i τ [27,31]. Therefore,…”

“…We assume that the processing time of IoT device i for its own task follows an exponential distribution with mean 1/µ F,S i when it processes all of its own task and any task of IoT device j is not offloaded to IoT device i (i.e., T M i = 2 and T O j = 0). In this case, the probability that the task is completed during a decision epoch is µ F,S i τ [27,31]. Then, the probability that a task is not completed during a decision epoch is 1 − µ F,S i τ.…”

“…On the other hand, if some portion of the task of IoT device j is offloaded to IoT device i (i.e., T O j = 0), the processing speed of IoT device i for its own task decreases, and thus it is assumed that the processing time of IoT device i for its own task follows an exponential distribution with mean 1/µ F,D i (> 1/µ F,S i ). In this case, the probability that the task is completed (or not completed) during a decision epoch is µ F,D i τ (or 1 − µ F,D i τ) [27,31]. Therefore,…”

“…Meanwhile, when offloading half of the task to IoT device j (i.e., T M i = 3), the remained task can be completed with shorter time. It is assumed that the processing time of the remained task follows an exponential distribution with mean 1/µ H,S i when any task of IoT device j is not offloaded to IoT device i (i.e., T O j = 0), and then the probability that the remained task is completed during a decision epoch is µ H,S i τ [27,31]. On the other hand, when IoT device i offloads the half of its task to IoT device j and processes the offloaded task from IoT device j (i.e., T M i = 3 and T O j = 0), the processing time of the remained task of IoT device i follows an exponential distribution with mean 1/µ H,D i .…”