Survey On The Mobility Management Of The UAVs Communication Network

In this dissertation, we investigated the mobility management problem caused by high mobility of UAV (Unmanned Aerial Vehicle) nodes in UAVs communication network, which is based on the function layered structure of UAV. The main works can be summarized as follows:1. The transmission architecture of the UAVs' beyond line of sight communication is analyzed. Based on the function layered structure of UAV, we analyze the UAVs communications communication network, which includes backup layer, relay layer and mission layer.2. Aiming at solving the location management problem in the UAVs communication network, we proposed the location database based on the tree hierarchical structure in order to get the minimum cost of location management of mission UAV nodes, particularly showed the operation process of location update and location lookup, and made out the composite location update scheme based on the hierarchical call protocol (HCP).3. The key technologies handoff management in UAVs communication network is also studied. From the easy degree of implement and system reliability point of view, it should make use of the signal strength of relay received by mission UAV node as the measure parameter for handoff, and apply the relative signal strength with hysterics and threshold initiation criteria. In addition, considering the particularity of UAVs communication network, we put forward the emergent handoff decision scheme based on the self control of mission UAV nodes, as well as the guard channel with first-in-first-out queue(GCM-FIFO) channel allocation strategy. What is more, the signal mechanism of normal handoff was presented too.4. The application of GCM-FIFO channel allocation strategy is particularly discussed as well. It uses the Markov Chain and Queue theory to model the system, and discusses the handoff performance as a function of the capacity of queue and the number of guard channels for handoff calls. Results show that, in order to achieve the best handoff performance in UAVs communication network, we should properly chose the capacity of queue and the number of guard channels according to the simulation results, when we apply the GCM-FIFO channel allocation strategy.