| The study and use of underground mine locomotive unmanned system hastremendous economic and social benefits. It could reduce transportation accidentprobability caused by scheduling and operation error.By building underground mine broadband mobile communication networklocomotive could transfer high-definition video stream, environment data and acceptcommand while moving. Underground mine broadband mobile communication networkis constructed based on802.11Wireless Local Area Network(WLAN), in WLAN whena mobile node leaves an access point’s coverage area, it has to handoff and reassociationwith another one, this procedure would lead to communication delay.To solve this problem two kinds of handoff mechanism are proposed: Fast handoffmechanism based on smooth selective scanning and dynamic caching algorithm(FHM)and QoS Guarantee Seamless Handoff Mechanism(QGSHM).FHM has no requirement on the topology of the network, satisfying thetransmission requirements of most wireless multimedia services. Through smoothselective scanning algorithm FHM reduces the number of channels to be scanned andskips the scan phase when cache hits, as a result the delay of the whole handoff phase isreduced.QGSHM is proposed based on the network layout characteristics of UndergroundMine Broadband Mobile Communication Network, including QoS Guarantee APSelective Algorithm(QGAS) and Dual-interface Seamless Handoff Procedure(DSHP).QGAS takes the load capacity, the received signal strength indicator value and thehandoff time limitation into consideration to select an access point meeting the QoSrequirements of the system. DSHP exploits the characteristic of the underground minebroadband mobile communication network, through the cooperation of thedual-interface in the mine locomotive to ensure the continuity of communication andrealize seamless handoff.The simulation results show that the handoff mechanisms proposed cansignificantly reduce the handoff delay, satisfying the QoS requirements of theapplication. |
PDF Full Text Request