Mesh clients in hybrid wireless mesh networks can perform the routing functionality, as well as provide end-user applications that are more suitable for tunnels, to improve the connectivity of backbone networks. In this article, based on the diversity of data and limited power supply of mesh clients in hybrid wireless mesh networks in underground mines, we propose a multi-criteria routing metric to support data-differentiated service. This routing metric divides data into two types: urgent and non-urgent. End-to-end delay is calculated when transmitting urgent data, and hop count and link load are measured when transmitting non-urgent data. In order to optimize the utilization of mesh clients and to prolong the network lifetime, mesh clients and mesh routers are given different weights in the calculation of hop count. Based on the QualNet7.1 simulation platform, the performance of the proposed routing metric in transmitting urgent and nonurgent data is evaluated through numerous simulations. Simulation results indicate that the routes selected using the proposed routing metric can effectively reduce the average end-to-end delay when transmitting urgent data and reduce the utilization rate of mesh clients while simultaneously guaranteeing the capability of the network when transmitting non-urgent data. This finding satisfies the differentiated service requirements of data of different types for hybrid wireless mesh networks in coal mines.

Hybrid wireless mesh networks are more suitable to tunnels in underground mines because mesh clients can perform the routing functionality and provide end-user applications. Types of data transmitted among hybrid wireless mesh networks in underground mines are diverse and power supply of clients is limited. Using virtual potential field, a routing algorithm is proposed to support data-differentiated service in hybrid wireless mesh networks. Based on network parameters, the hybrid wireless mesh networks are abstracted as potential fields. The hop count is used to build the depth potential field. The residual energy of nodes is converted into penalty factor to symbolize the used buffer spaces of nodes, which is used to construct resource potential field to support different types of data. According to the different demands of data transmission, the proportion of these two potential fields is adjusted by a regulatory factor to form a hybrid potential field. The data packets are driven to move toward the gateway in the hybrid potential field at the same time to achieve high quality of service. Simulation results demonstrate that the proposed routing algorithm has shown better performance on end-to-end delay, delivery ratio, and network lifetime, compared with similar algorithms.

Hybrid wireless mesh networks are suitable to construct emergency communication networks after disasters in underground mines. The routing decision in emergency scene is more difficult to give an accurate mathematical description due to the constraints of various data types, different data transmission requirements, and multi-parameters. Based on the fuzzy decision theory, this article has proposed a fuzzy-logic-based data-differentiated service supported routing protocol. Through the use of the adaptive fuzzy decision system, fuzzy-logic-based data-differentiated service supported routing protocol can provide data-differentiated services and make optimized routing decisions to satisfy the transmission requirements of different data types. In addition, a path soft handoff strategy has been proposed to maintain continuous data transmission when the path quality deteriorates. Based on NS2, we set three transmission scenarios (transmitting emergency data, regular data, or mixed data) to test the performances of fuzzy-logic-based data-differentiated service supported routing protocol, ad hoc on-demand distance vector, FUZZY-ad hoc on-demand distance vector, and multi-criteria routing metric. The results show that the fuzzy-logic-based data-differentiated service supported routing protocol has a higher delivery ratio and lower end-to-end delay when transmitting emergency data. When transmitting regular data, fuzzy-logic-based data-differentiated service supported routing protocol has achieved higher throughput and longer network lifetime than that of similar algorithms.

Hybrid wireless mesh networks are suitable for complex environment communication in coal mine. Mesh clients with application service and routing function in hybrid wireless mesh networks can form a highly robust hybrid network with mesh routers. The processes of nutrient flux transfer and path choice in Physarum network are similar to data transmission and routing selection in hybrid wireless mesh networks. In this article, we use Physarum-inspired autonomic optimization model to design a Physarum-inspired multi-parameter adaptive routing protocol to improve the service quality of coal mine hybrid wireless mesh networks. Physarum-inspired multi-parameter adaptive routing protocol has achieved distributed routing decision by drawing the hybrid wireless mesh network parameters into Poisson's equation of Physarum-inspired autonomic optimization model to measure the quality of link and implements two adjustment strategies to make the protocol more adaptive. The resource-dependent adjustment, which considers the irreversible energy consumption and recoverable buffer occupation, makes the energy consumption problem prominent when there is a lack of energy. The position-dependent adjustment makes routing decision efficient according to the load of different positions, which is caused by many-to-one data transmission model in coal mine. Based on NS2, simulation experiments are performed to evaluate the performance of Physarum-inspired multi-parameter adaptive routing protocol, and the results are compared with those of ad hoc on-demand distance vector, HOPNET, ANT-DSR, and Physarum-inspired routing protocols. The experimental results show that the route path selected by Physarum-inspired multi-parameter adaptive routing protocol is better than those selected by the other four protocols in the performance of average endto-end delay and delivery ratio. The balance of energy consumption and network load is achieved and the network lifetime is effectively prolonged when using Physarum-inspired multi-parameter adaptive routing protocol.