Performance Evaluation of the Wireless Sensor with Renewable Energy, Impatience, and Heterogeneous Energy Requirements

• Main Authors: Mei-Jun Liao, 廖梅君
• Other Authors: Shun-Ping Chung
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/beruyx

碩士 === 國立臺灣科技大學 === 電機工程系 === 107 === Wireless sensors are extremely important in today's era of big data. Data collected in the environment needs to be transmitted through the wireless sensor network. On one hand, wireless sensors need energy to complete the transmission service. On the other hand, the energy capacity of a wireless sensor is limited by its small size. To extend the lifetime of each wireless sensor, the energy harvesting method can be utilized to collect renewable energy. Our research assumes that the solar energy is collected via the energy harvesting method to support the transmission needs of wireless sensors. In order to provide better bit error rate or data rate, the energy requirement of a packet may be more than one unit of energy. Furthermore, a packet may leave without finishing the service due to impatience if the patient interval is exceeded. In this work, we study three scenarios for wireless sensor networks: one class of impatient customers, two classes of impatient customers, and multiple classes of impatient customers. In the first scenario with one class of impatient customers, we focus on the cases where each customer waiting in the queue becomes impatient and requires only one energy unit to start the service. We use a two-dimensional Markov chain to describe the first system. In the second scenario with two classes of impatient customers, each customer has to consume one or two energy units to start the service. We use a three-dimensional Markov chain to describe the second system since we have to determine whether the customer becoming impatient is at the head of line in the queue or not. In the third scenario with multiple classes of impatient customers, each customer of different classes has to consume different energy units to start the service. We use a three-dimensional Markov chain to describe the third system. First, we derive the analytical models for the systems considered. An iterative algorithm is utilized to find the steady state probability distribution and performance measures of interest. Second, an approximation method is proposed to calculate the waiting time in the queue for the customers completing the service. Third, the impacts of different system parameters on the performance measures of interest are studied. Last but not least, the computer simulation program is written in C language. In most cases studied, the analytical results are shown to be in good agreement with the simulation results.