# Communication Infrastructure Design for Reliable UAV Operations in Air Mobility Corridors
## 2 Materials and Methods  
### Radio Network Architectures for Corridor Coverage  
This study examines four distinct strategies for deploying radio repeater stations along UAV air corridors to ensure continuous and reliable communication between UAVs and ground control systems. The analysis focuses on the spatial arrangement of repeaters, the extent of coverage overlap, and the resulting level of communication redundancy. Each strategy is represented graphically and conceptually, using a simplified model of a straight corridor between two points, A and B, with a total length, \(D\). The coverage radius of each radio repeater is denoted as \(R\). The deployment strategies are defined as follows. Strategy 1. Non-overlapping coverage (single coverage). In the first deployment strategy, radio repeater stations are arranged along the UAV flight corridor at regular intervals such that their coverage zones, each with a radius, \(R\), are adjacent but do not intersect (Figure 2). Figure 2: Configuration of deployment strategy 1. The distance between two neighboring repeaters is exactly \(2R\), which ensures that the entire corridor is covered without any gaps but also without any redundancy. At any given point along the corridor, a UAV is within a communication range of only one radio station. The total number of repeaters \(N_{1}\) for the first strategy is  
\[N_{1}=\left\lceil\frac{D}{2R}\right\rceil \tag{1}\]  
This configuration is the most efficient in terms of the number of repeaters required to span the full corridor length, making it cost-effective and simple to implement. However, it lacks resilience: if any single repeater fails, communication is completely lost within its segment, potentially compromising UAV safety and control. As a result, this strategy is suitable only for low-risk environments where the likelihood and consequence of communication loss are minimal. Strategy 2. Fully overlapping coverage (dual coverage). The second strategy improves reliability by positioning the radio repeater stations closer together so that each coverage zone overlaps fully with the next (Figure 3). In this case, the spacing between adjacent stations is reduced to \(R\), meaning that the edge of one station's coverage area reaches the center of the next. This design ensures that every point along the UAV corridor is simultaneously covered by two radio stations. If one repeater fails, the other can continue to maintain communication with any UAV in the affected zone. This overlapping configuration significantly enhances redundancy and fault tolerance, making it highly reliable for urban environments or critical operations where communication must always be preserved. The trade-off is an increased number of repeater stations required to cover the same corridor length, resulting in higher installation and maintenance costs. Nevertheless, this strategy is often justified in scenarios where safety and uninterrupted data exchange are top priorities. The total number of repeaters \(N_{2}\) for the first strategy is  
\[N_{2}=\left\lceil\frac{D}{R}\right\rceil \tag{2}\]  
Since the distance between stations is \(R\), twice as many repeaters are needed compared to Strategy 1 for the same corridor length, ensuring each point is within range of two stations. Strategy 3. Alternating redundant coverage (mixed redundancy). The third strategy introduces a balanced approach that provides enhanced communication reliability while optimizing resource use. In this configuration, repeater stations are spaced at intervals of \(R\), like Strategy 2, but redundancy is added selectively. Every second station along the corridor is duplicated, forming alternating patterns of single stations and paired stations (Figure 4). Figure 3: Configuration of deployment strategy 2. This creates a \"single-pair-single-pair\" arrangement that results in overlap by three stations of coverage zones across the corridor. The design ensures that even if two adjacent stations fail, communication can still be maintained by a functioning repeater within range.