# Routing Algorithm for Sensor Network Monitoring the Condition of Mining Equipment
## 2 Characteristics of Sensory Network Design in Hazardous Areas  
Sensors mounted on the powered roof support include inclinometers, oil pressure sensors in the hydraulic legs and a wall face distance measurement module [17; 18]. It is necessary to develop a routing algorithm (to manage data transmission in a network of sensors operating on a powered roof support), regarding the entire sensor network design process.  
The first element to be considered when designing a sensor network is the characteristics of the environment in which the network will operate. Deployment of nodes of the network as sensors on a powered roof support operating in a longwall complex requires radio visibility of the access point. Deployment of the sensors does not secure radio visibility of the access point by each sensor, so a mesh topology is suggested for the network (in this topology, one sensor can transmit data to its neighbour). The sensor closest to the access point collects data from the grid and transmits them by a flameproof computer to the surface.  
The design of the sensors (grid nodes) installed on the longwall complex must comply with the requirements of the ATEX directive [19], in the area of group I, category M1 equipment with intrinsic safety protection 'ia'. The requirements for the design of the equipment enclosure mainly concern the surface resistance and mechanical strength. The electrical systems must be protected with regard to limiting the radiated energy of the radio beam and the battery power supply in the hazardous area. The designed routing algorithm should ensure adaptation to the design of a specific sensory network. The following criteria were adopted in evaluation of the algorithm:  
* Packet arrival time to destination--selecting the route for the data packet that will be the shortest path to the access point. By optimising according to this criterion, it will be possible to increase the sampling time of such a network without having to buffer the data. It is assumed that simple microcontrollers (with small internal memory capacity) are installed in the nodes, due to the need for low power consumption. However, it is necessary to increase the sampling rate due to the need to record phenomena such as sinkholes and collapses so that they can be predicted and thus counteracted later.
* Network throughput, data transmission speed--we also want the network to be able to transmit as much data as possible at any one time, using the maximum available throughput of the radio modules.
* Energy consumption--minimising energy consumption to compensate the energy losses by electrical protection devices that increase energy consumption (using additional resistance to reduce the current causes the battery energy to dissipate as heat); minimising energy consumption also affects the use of smaller-sized batteries, which again reduces the size of the enclosure, reducing the surface where static charge can build up.
* Packet deliver ratio--reliability of operation; confirmation that the measured data reaches the recipient and is not lost. The lack of data buffering, due to limited internal memory, forces the algorithm to be more reliable in delivering data to the destination--protocols do not have mechanisms for confirming transmission.