Design and Implementation of Smart Multi-Channel MAC Protocol for Industrial Wireless Sensor Networks

Abstract

Nowadays, Industrial wireless sensor networks (IWSNs) play an important role in industrial applications due to their low cost, low power consumption and flexibility. They can be used in a wide range of applications on monitoring the environment, mobile robots, and mobile Supervisory Control and Data Acquisition (SCADA). With this type of application, IWSNs must meet the requirements of industrial network standards such as the reliability of data transmission, timeliness of the system that rapidly responds to real-time events with appropriate action, and low energy consumption. Unfortunately, the data delivery of IWSNs may be affected by the collision, multi-path fading since it is delivered via the wireless communication link. Therefore, we need to design protocols for IWSNs that are able to achieve reliability on data transmission, high throughput for a timely response for real-time system and low energy consumption. In this thesis, a new medium access control (MAC) and a cross-layer protocol for industrial wireless sensor networks are proposed to meet the requirements of the industrial network standards. In wireless networks, the collision occurs frequently since the packets are transmitted inherently. The collisions not only waste energy and decrease bandwidth, but also destabilize the system. Therefore, a MAC protocol with removing collision mechanism is proposed to guarantee the reliability of data transmission. The collision is removed based on assigning the different delay time to the nodes before performing CCA. To assign the different delay time to nodes, the Number Conflict Resolution NCR) algorithm and Blind Learning BL) are proposed. It is proven by simulation and analysis that the new MAC protocol improves throughput by 29.5% to 71.6%, and reduces energy consumption by 20.5% to 36.2%, compared to the recent best approach using MAC messages. Simulation data are also verified by experimental data. Based on the proposed MAC protocol, we develop a cross-layer protocol that is exploited by combining the MAC layer and Network layer to achieve outstanding performance. The nodes are divided into multiple levels: and the data is transmitted level by level from the highest level to the lowest level (a sink). Each level is assigned the active time for receiving and sending data. For data transmission in each level, the above removing collision is combined with a channel assignment mechanism for increasing parallel transmission. The channels are assigned to every node such that every two neighboring nodes use different channels. Furthermore, a dynamic routing scheme is proposed to support the sender in selecting an available node more easily to send data that robustness for the changing of topology in which each node will choose a parent node by itself, and the parent node can be changed in every DACT based on learning the node’s status. By simulation and analysis, it is proven that the proposed protocol can improve throughput by 127% to 167%, and save energy by 13% to $36%, compared to its ancestors.