On The MAC Protocol Of TTNT

As the newest generation of tactical data link system of U.S. military, Tactical Targetting Network Technology(TTNT) System is capable of attacking the transient moving target, and realizes truely the ability of "Find and Kill". The claim of 2-millisecond of burst transmission delay in a hop distance of 185 kilometers is in accordance with the pursuit of the evolving 5G communication technology. And also, the high-speed broadband, IP-based Ad hoc networking scheme of TTNT can give full play to the distributed networked operational effectiveness. The research on TTNT is of great significance to both the development of communication technologies and the upgrading progress of our own data link system. This thesis is mainly an exploration of the Statistical Priority-based Multiple Access (SPMA) protocol of TTNT’s MAC layer.The main results obtained are as follows:1) An analysis is made combining the working scenarios and traffics of TTNT, then 8 types of services appear and are distinguished from that of wired network multimedia services. Considering the bandwidth guarantee of each user, we get the arrival rates, service rates and traffic strength ratios of different types of services. Thus, it is possible to make an assurance of the prioritization and the low queueing delay of the highest priority services.2) A method, Rapid On-Off-Division (RODD), is found from the literature that can be used to solve the contradiction between the low delay command and the packet error rate requirement of TTNT. The method sounds like the time-division multiplexing or the code-division multiplexing, but actually has produced a qualitative change. It can realize the virtual full duplex and multi packet reception (VFD-MPR) function, and further a VFD-MPR multiple access scheme. Then, it is possible to approach the extremely low latency.3) Startting from the perspective of the time-scale swiching, the author find that SPMA protocol can be seen as a combination of four multiple access schemes, exactly the VFD-MPR multiple access scheme, the multi-channel frequency-hopping rendezvous multi-access scheme, the priority-queueing multiple access scheme and the directional-antenna multiple access scheme from the viewpoint of time, frequency, services and space domain, respectively. There are some definite similarities among the four multiple access schemes. The thesis introduces the first three schemes in Chapter 5 since they can reduce effectively the access delay. The fourth one is mentioned in the Conclusion part.4) Assuming a certain similarity exists between the network services and the user services in traffic strength, we establish the relationship between two of the three key parameters of SPMA protocol so as to build a bridge between the external channel occupancies and the internal priority queues of one user. Referring to the traffic partition of TTNT aforementioned, we give the parameter settings of the priority thresholds. Thereby, the channel occupancies statistics can be compared directly with each priority threshold.