Research Of TDMA Protocol In Tactical Data Link Under QualNet Environment

The development of Tactical Data Link is one of the important signs in the modern warfare. The application of Data Link affects significantly the ability and the level of informationized warfare since the communication protocol determines tactical data link network performance to a great extent. TDMA is one of mainstream network protocol used in current tactical data link. Therefore, research of TDMA protocol in tactical data link is an important military communication subject. Therefore, this thesis mainly studies TDMA protocol in Tactical Data Link.TDMA protocol in Tactical Data Link adopts fixed time slot pre-assignment technology. In network cycle time each unit takes a time slot for data transmission. If one unit or several units have lots of messages to transmit, using the above technology, each unit can only transmit one time in each network cycle time. In each time slot, message number to send is limited, so these units' buffer will save large numbers of messages. If waiting overtime, some messages will be deleted. Therefore, a new time slot management scheme is proposed in this thesis, and implement dynamic TDMA. In dynamic TDMA protocol, each unit may apply for extra time slot according to traffic quantity, then network control unit makes decision on whether to assign a time slot. Large traffic units have more opportunities for transmission in a network cycle time. So message drop rate is reduced, and network thruput is increased. In dynamic TDMA, since time slot proportionality factor (δ) effects the network performance, it is very important to investigate the factorδ.The thesis is organized as follows, based on the analysis of TDMA in Tactical Data Link, a new time slot management scheme is firstly proposed; then, system modeling, simulation experimental results are described; followed by the dynamic TDMA network performance evaluation, and the comparative analysis of TDMA and dynamic TDMA performance; finally, the influence ofδon network performance is investigated and concluded.