摘要：Due to the recent saturation of the traditional telecom markets, the vendors are shifting their focus on to the vertical markets, including but not limited to oil and mine industries. This paper is offering a solution for one of the key issues the mine industry is facing. When the accident happen under the mine, the first thing to do is to locate the workers, there are many methods been proposed; however, each has pros and cons. For example, we can use RFID to locate the people, the problem is when there are too many miners at the same spot, the method doesn’t work well; we can use CDMA indoor GPS system to locate the person, however, the base station is not cheap; we can use IEEE802.15 Zigbee system to locate people, but we need huge amount of nodes to cover reasonable size of mine; for these reasons, we propose to use low cost WiFi system to fulfill the task. We introduce IEEE1588 Precision Timing Protocol into the existing WiFi or similar mesh networks, to increase the Time of Arrival ranging accuracy. This way, with limited increasing of the system cost, we satisfy the customer requirements. To prove the concept, Matlab is used to work out the theoretical bit-flow vacation model and the simple linear-ranging algorithms.
关键词：wireless packet network;precise time synchronization;emergency miner locating
