# Communication Infrastructure Design for Reliable UAV Operations in Air Mobility Corridors
## 2 Materials and Methods
### Adapting Air Mobility Communication Design in Broken-Line UAV Corridor Topologies  
The preceding analysis has focused on idealized linear corridors. However, real-world UAV air corridors in urban environments frequently follow non-linear paths with multiple bends and segments, as illustrated in Figure 10. This section extends the deployment strategies and reliability analysis to these more complex corridor configurations. For non-linear corridors with multiple segments, the deployment strategy requires strategic adaptation of the principles established earlier. Radio stations must be positioned at each bend or node of the corridor (as shown with RS2 and RS4 in Figure 10), serving both as communication hubs and critical navigation reference points. These strategically located stations provide essential coverage at decision points where UAVs must change direction while establishing reliable reference points for navigation using radio direction finder techniques like those long employed in traditional aviation. Adjacent radio stations must operate on different frequencies to prevent interference while enabling UAVs to distinguish between signals from multiple sources. This frequency separation allows UAVs to determine their relative position through signal strength comparisons, navigate accurately along the intended path, and transition smoothly between corridor segments by homing in on the next node's frequency. Each straight segment between nodes is treated as an individual linear corridor where the previously analyzed deployment strategies can be applied, with the selection varying between segments based on length, criticality, environmental conditions, population density beneath the segment, and expected UAV traffic volume. The reliability analysis for non-linear corridors builds upon the Markov modeling approach established earlier, with particular attention to node criticality. Nodes represent potential single points of failure if not properly reinforced, as UAVs must receive clear signals to execute direction changes, and loss of node coverage could affect multiple corridor segments. To address this vulnerability, radio stations at nodes should implement Strategy 4 (complete duplication) regardless of which strategies are used for the connecting segments. From a reliability modeling perspective, the communication availability of each segment can be calculated independently using the formulas derived in Section 2.2. The overall corridor reliability then becomes the product of the availability values for all segments  
\[A_{corridor}=\prod_{i=1}^{z}A_{i} \tag{14}\]  
where \(A_{i}\) is the availability of segment \(i\), and \(z\) is the total number of segments in the corridor. Special consideration must be given to the transitional zones where UAVs move from one segment to another, as communication availability in these zones depends on the overlap of coverage from stations in both segments, the reliability of the node station, and the UAV's ability to successfully transition between frequencies. Based on these considerations, a hierarchical approach to deploying communication infrastructure for non-linear corridors is recommended. This begins with critical node reinforcement using Strategy 4 at all corridor nodes, followed by segment classification based on length relative to repeater coverage radius, proximity to sensitive urban areas, expected traffic density, and environmental challenges to signal propagation. The appropriate deployment strategy can then be applied to each segment: Strategy 4 for highest-risk segments, Strategy 3 for moderate-risk segments, Strategy 2 for lower-risk segments, and Strategy 1 only for experimental or temporary deployments in minimal-risk areas. A comprehensive deployment strategy is also provided in the next section. Figure 10: Repeater placement in a bent UAV flight corridor. sive frequency allocation plan ensures adjacent stations operate on different frequencies, minimizes potential interference, and accommodates future corridor expansions.