1. Introduction
 We study the problem of energy utilization that resulted by data transmission in IoT devices that use capacitors to receive wireless energy. Different from existing studies, if the sensors use capacitors to receive wireless energy, the wireless energy receiving rate changes over time, and it gets slower and slower.
 If the IoT sensors do not have enough wireless energy receiving time, the minimum completion time problem, which transmits all the data, is studied. An online algorithm is provided and the competitive ratio is $\frac{n+3}{n+1}$.
 If the IoT sensors have enough wireless energy receiving time, the problem of transmitting the max amount of data is studied. Two cases for this situation where there is only one energy receiving period and there are multiple energy receiving periods are studied. Two competitive ratio online algorithms for both of these two cases are provided in this paper.
2. Preliminary and Problem Statement
3. The Sensor Can Receive Enough Wireless Energy
3.1. Only One Huge Block of Data
3.2. Data Arrives at Different Times
Algorithm 1: Minimize the total completion time. 
Input: One enough long wireless energy receiving period ${E}_{1}=[0,+\infty ]$, and n data blocks $\{{D}_{1},{D}_{2},\dots ,{D}_{n}\}$, each ${D}_{i}=\langle {a}_{i},{b}_{i}\rangle $ denotes an online block of data with size ${b}_{i}$ arrives at time ${a}_{i}$. Output: Find a solution to minimize the completion time of the data transmission.

4. Not Enough Wireless Energy Receiving Time
4.1. Receiving Only One Period of Wireless Energy
4.1.1. Only One Block of Data with an Extremely Large Size
4.1.2. Multiple Data Blocks Arrivng at Different Times
Algorithm 2: Transmission algorithm when data arrives over time. 
Input: One wireless energy receiving period ${E}_{1}=[0,T]$, and n data blocks $\{{D}_{1},{D}_{2},\dots ,{D}_{n}\}$, each ${D}_{i}=\langle {a}_{i},{b}_{i}\rangle $ denotes an online block of data with size ${b}_{i}$ arrives at time ${a}_{i}$, $1\le i\le n$. Output: Schedule the data transmission to maximize the amount of transmitted data.
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4.2. Receive Multiple Periods of Wireless Energy
Algorithm 3: Transmission algorithm when data and energy receiving time arrive over time. 
Input: m wireless energy receiving periods $\{{E}_{1},{E}_{2},\dots ,{E}_{m}\}$, and n blocks of data arriving over time, where ${E}_{j}=[{s}_{j},{e}_{j}]$ represents the jth period of energy receiving period, and ${D}_{i}=\langle {a}_{i},{b}_{i}\rangle $ indicates an online block of data with size ${b}_{i}$ arrives at time ${a}_{i}$. Output: Find a solution to maximize the amount of successfully transmitted data
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5. Evaluations
6. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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