| The current popular wireless network air interface technology adopts MAC protocol based on CSMA/CA strategy.The prominent problem is that when the network scale is large,the channel access conflict rises rapidly,the network performance drops sharply,and even timely communication cannot be guaranteed.Therefore,the Ad hoc networks of MAC layer protocol based on TDMA will have wider application prospects in military communications and disaster relief emergency communications.In order to support the information transmission of large-scale nodes,the transmission delay of the traditional TDMA protocol cannot meet the needs of emergency information transmission.This paper designs a dynamic TDMA slot allocation protocol RA-SOTDMA,which completes the slot occupation through channel monitoring,slot reservation and reservation confirmation,and constructs single-hop and two-hop slot tables ensure conflict-free communication of channels within the multi-hop range.And adopt a perfect slot release mechanism to ensure the flexibility of channel occupation and overcome the impact of network topology changes.Time synchronization is the core technology for Ad hoc network to implement TDMA mechanism.The technical difficulty lies in how to support dynamic network topology,multi-hop communication and high synchronization accuracy.In this regard,this paper also designed a fast level synchronization algorithm FLS.In response to the dynamic topology of Ad hoc networks,FLS has formulated network access synchronization and periodic synchronization mechanisms to provide guarantees for synchronization accuracy.The node-level strategy is adopted to optimize the network structure and ensure the complete network time synchronization under the condition of low network overhead.Finally,on the wireless platform based on CSMA commercial network card,the wireless network card with TDMA mechanism was developed and the TDMA performance was evaluated and the time synchronization accuracy was tested. |
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