Research And Simulation Of High Dynamic High-altitude Platforms Network Access And Handoff Technologies

In recent years, with the special strategic position of high-altitude platforms, the military strategic value of high-altitude platforms network has drawn more and more attention, and many countries have invested a lot of money and talents for its in-depth research. Infusing high-altitude platforms in the integrated information networks of land, sea, air, and space will play an important role in the construction of the new China’s aerospace and oceanography capacity expansion system. For our country, strengthening the research of high-altitude platforms is both an opportunity and a challenge. The particularity of high-altitude platforms environment puts forward a new technical challenge for high-altitude platforms network.Firstly, the reasonable high dynamic high-altitude platforms network model was designed. On this basis, the in-depth study of high dynamic high-altitude platforms network access and handoff technologies was carried out:1) For high dynamic high-altitude platforms network access technology, the thesis has proposed the on-demand allocated dynamic TDMA protocol based on traffics priority. On the basis of inheriting the timeslot concept of the fixed TDMA, the proposed access technology has avoided the waste of timeslot resources by allocating the timeslot resources on-demand for the traffics of the mobile terminals, thereby improving the performance of the entire network. To provide the priority support for different traffics of the terminals in the high-altitude platforms network, the proposed access protocol has reserved some timeslots for the high-priority traffics of the terminals in the access request phase, and only provided a contend timeslot for the low-priority traffics, realizing to guarantee the QoS of the high-priority traffics. In addition, the proposed access protocol has improved the utilization of dynamic TDMA timeslots by dynamically adjusting guard time.2) For high dynamic high-altitude platforms network handoff technology, considering the handoff trigger lag caused by high dynamic of the terminals, the thesis has proposed the handoff trigger criteria based on the dynamic hysteresis margin, which has comprehensively considered the received signal strength and the speed of the terminals in the handoff trigger phase. Considering the load imbalance caused by the concurrent handoff of multiple access terminals, the thesis has proposed a load balancing handoff criterion based on RSSI and energy-aware, which has comprehensively considered the residual energy of the high-altitude platforms and the received signal strength of the mobile terminal when selecting the target high-altitude platform.Finally, both the proposed access technology and handoff technology have been simulated on OPNET platform. By comparing with the traditional access technology and handoff technology respectively, the results have verified that the proposed access technology and handoff technology could better meet the requirements of the high dynamic high-altitude platforms network. The research of the thesis can provide the theoretical guidance for the Aero & Space networks and near space research in our country, and has some reference value.