Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ELC-WSN Application on Mine Coalface Monitoring] Date Submitted: [2 May, 2011] Source: [Pingping Xu, Shen Zhang, Xiaohu Zhao, Hao Liu] Company [Southeast University, China University of Mining and Technology， Beelinker Technology Co., Ltd] Address [2 Si Pai Lou,Nanjing,210096,China；IoT Center, CUMT, Xuzhou 221008,China，339 Linquan Road, Suzhou Industrial Park, 215123,.China] Voice: [86 25 83794525，86 516 83899702 ], Email: [xpp@seu.edu.cn, xzzhsh@pub.xz.jsinfo.net,] Re: [Application Spaces] Abstract: [Application on Mine Coalface Monitoring] Purpose: [This document is a response to Application Spaces.] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.4k

2. Background • Chinese Output of Coal Mine up to 320 Billion in 2010, Ranking First around the World. • Over 7 Million miners in Chinese Mine but mine Disasters happen Frequently. High-reliable safety monitoring is urgent for Chinese Mine. • Most of disasters happened in coalface area. • Coalface monitoring are difficult and expended nationally. Underground Coalface Environment

3. WSN may promote mine safety Sensor node Sensor nodes hang under the supporters • WSNs monitoring system applied to coalface is especially suitable to follow the advance of working face when nodes are hang under hydraulic supports. • Concentration of coal dust, gas, temperature, mine pressure, the status of equipments, water level, etc., should be monitored properly all the time to evaluate the safety of coalface, and hence the safety of the miners. • Instead of installing many cables, which is not practical in mine tunnels, the collected data from local sensors can be transmitted to the management station through multiple hops in the wireless channel.

4. Two rows of hydraulic props divide the coalface into three communication spaces: communication space 1, communication space 2 and waste area Direction transmission Network Waste area Hydraulic props Multi-hop transmission network Communication space 2 Base Station Hydraulic props Multi-hop transmission network Communication space 1 Coal Wall Optical Fiber Cable To Backbone Underground The distance of coalface is about 150m ~300m long Slide 4

5. The usage of the three heterogenous networks 1. The WSN in waste area is a direction network, all nodes should transmit data towards communication space 2. The nodes in waste area are disposable nodes, and can not be retrieved. Objective: Real-time monitoring of collapse of top roof and temperature rising due to the oxidation of coal in waste area where people do not permitted to enter. 2. The WSNs in communication space 1 and space 2 are multi-hop network. The nodes in these two spaces are moving with hydraulic supports. Objective: Rea-time monitoring of coal dust, gas, mine pressure, the status of equipments, water level, etc. 3. Even though the same WSN nodes can be used to construct the three networks, but the structure and routing are different, the network for coalface is actually a heterogenous network.

6. Expected on tech requirements for ELC-WSN • Energy consumption - all the WSN devices in coalface should be powered by battery and the consumption current is better at several µAs. • Adjustable Duty Cycle - In emergent case, WSN must work in real-time stage • Transmission power - to ensure the safety in mine environment, wireless transmit power should less than 10mW • Transmission distance - one hop distance may >30m in coalface and with good diffraction performance in tough environment and in collapsed waste area. • Networking - networking in waste area is disposable,but in communication space 1 and space 2, the networking must be easy to re-deploy by self due to the frequent-advance of coalface and less tech supporting. - networking size should be scalable and topology should be adapt to variation. - network routing should be adaptive to the heterogenous network.

7. IEEE802.15.4 is one Possible Mine coalface Application • Data rate - text and small pictures (< 300kb per picture) transmitted within one minute as the user passing the coverage of information node. • Transmission distance - one hop distance ~ 30m • Energy consumption - The applications requires device work last long without battery replacement. • Network - The network must be easy to re-deploy due to the frequent-advance of coalface. • Transmit power - Transmit power should less than 10mW • 802.15.4 • Low data rate (20 to 250 kb/s) • Short distances (10 to 30m) • Multi-year battery life • Little or no infrastructure • < 1mW