Service Aware Traffic Distribution in Heterogeneous A2G Networks

Sammanfattning: Airplanes have different ways to connect to the ground, including satellite air-to-ground communication (SA2GC) and direct air-to-ground communication (DA2GC). Each connection/link offers a different varying amount of transmission capacity over flight time. The traffic generated in the airplane must be forwarded/sent to ground over the available links. It is however not clear how the traffic should be forwarded so that traffic quality of service (QoS) requirements are met. The thesis at hand considers this question, and implements an algorithm handling the forwarding decision with three different forwarding schemes. Those consider traffic parameters in calculating a value assigned to each traffic flow, over a combination of priority, delay requirement and the number of times a traffic flow is dropped. The forwarding algorithm relies on proposed in-flight broadband connectivity (IFBC) network traffic and air-to-ground (A2G) link models, which aim at approximating the network environment of future IFBC networks. It is shown that QoS requirements of traffic flows in terms of packet loss and delay cannot be satisfied with capacities offered by current DA2GC and SA2GC technology. For a future scenario, with higher assumed link capacities, the QoS requirements are met to a higher extent. This is shown in lower packet loss and delay experienced by the respective traffic flows. Further, it is shown that the performance can be improved with specific forwarding schemes used by the forwarding algorithm. It is also investigated how a web cache can be used as a fallback technology. For this a required web cache hit rate is found, which should be high enough to offload the network with content served from the cache. Overall, the thesis aims at proposing an efficient traffic forwarding technique, and at giving insight into an alternative if this technique fails.