Topology optimisation of airborne communication networks
Global mobile data traffic continues to double every year according to communication industry’s forecasts. For data services to be available in the aircraft cabin at the future scale of demand, high-bandwidth internet connectivity far beyond today’s capabilities is needed.
Therefore, Bauhaus Luftfahrt analyses airborne communication networks based on laser communication. Here, aircraft not just send and receive, but also combine, relay and route data traffic, with various modes of ground connection of aggregated data streams. While this concept promises step-change improvements in connectivity, bandwidth and cost, the network topology optimisation remains a major challenge, especially with respect to resilience and terrestrial internet access.
Design and optimisation of such networks require a profound understanding of the performance potentials of technologies and architectures. Within the boundaries set by the air traffic system, the network must be optimised with regard to connectivity and throughput, considering link dynamics and data volumes. As the node distribution changes continuously and links may break due to range limitations and weather influence, network resilience is a crucial requisite for the concept, and by careful arrangement of network access stations, this requirement can be achieved. The evaluation of bitrate-distance statistics (i. e. air-to-X links) shows that the relocation of access stations along a flight corridor optimises connectivity and requirements on individual links. This result provides guidance towards optimised technology and architecture decisions for future implementations.
- Reduction of bandwidth requirement with gateway redistribution: Probability distribution of bitrate-distance requirement on links for two topologies with gateways at the boundaries of a corridor (left) and at the centre (right). Access point relocation to the centre lowers bitrate demand and improves connectivity (see below).
- (Network) Connecticity statistics for all aircraft: In scenario 1, only 25 % of aircraft connect at all times, and 100 % connectivity is never achieved. In scenario 2, 50 % of aircraft connect at all times, doubling the number, compared to the first scenario.