Models
Fiber
The fiber path model identifies the shortest and most cost-effective paths for connecting unconnected points of interest (POIs) to the existing optical fiber network using the road network. By minimizing the total length of fiber required, this model reduces overall deployment costs while efficiently extending connectivity.
To start with, the model connects POIs and fiber nodes to the existing road network using straight lines (unless they are already on the road network). Then, for each unconnected POI, it computes the shortest path to all fiber nodes. POIs that are already connected to the fiber network can also act as fiber nodes, from which the fiber network can be extended.
Figure: Graph initialization and fiber path algorithm
At each step of the algorithm, new connections are made between connected and unconnected points as long as the length of the new connection is below a specified threshold. For example, it can be specified that no single fiber line should be longer than 5 kilometers.
This approach enables economies of scale: POIs can act as relay points for neighboring POIs, enabling connectivity without each one needing to connect directly to a transmission node. This approach optimizes resource usage and simplifies network expansion.
In practice, this model is an application of Kruskal's algorithm to find a Minimum Spanning Tree (MST) in a network graph, where the edges are the road network and the vertices are POIs and fiber nodes. The MST ensures the minimal fiber path necessary to connect all relevant points while adhering to road network constraints related to distance.
Figure: Output of fiber path algorithm
Feasibility
Fiber is considered a feasible technology for a POI if the algorithm is able to connect that POI to the fiber network, given the algorithm constraints - particularly the maximum length of fiber allowed per connection. In practice, fiber will not be feasible for POIs that are very far away from transmission nodes or other POIs.
Required data inputs
- Points of interest
- Transmission nodes
The data on the road network is automatically fetched by the model from OpenStreetMap.
Model parameters
| Description | Example value |
|---|---|
| Maximum connection length (meters) | 50,000 |
| Annual hardware maintenance and replacement costs (USD per year, as a fraction of hardware CAPEX) | 0.1 |
| Access bandwidth cost (USD per Mbps per year) | 31.8 |
| Transit bandwidth cost (USD per Mbps per year) | 12 |
| Fiber cost (USD per km) | 8,000 |
| Hardware setup cost (USD per POI) | 500 |
| Hardware refresh after (Years) | 3 |
Cost model
The fiber cost model is summarized below. The CAPEX cost for each POI is dependent on the amount of fiber required to connect that school.
Figure: Fiber cost model
Cellular
The cellular model relies on cellular coverage analysis. If mobile coverage contours are provided, such as in the Figure below, then the coverage status is determined by overlaying the POIs over this layer.
Figure: Mobile coverage contours
If no mobile coverage contours are provided, then the locations of cell sites have to be provided and mobile coverage is determined by the distance from a cell site. Each site is assumed to provide coverage within a specified maximum radius, which is controlled by the model parameter Coverage radius around cell tower.
Feasibility
Cellular is considered a feasible technology for a POI if it is within the cellular coverage area.
Required data inputs
- Points of interest
- Cell sites or Mobile coverage contours
Model parameters
| Description | Example value |
|---|---|
| Coverage radius around cell tower (meters) | 1,000 |
| Reinvest into hardware after (USD per year, as a fraction of hardware CAPEX) | 0.1 |
| Access ISP fees (USD per Mbps per year) | 24 |
| Annual traffic fee (USD per Mbps per year) | 12 |
| Hardware setup cost (USD per POI) | 80 |
| Reinvest into hardware after (Years) | 3 |
Cost model
The cellular cost model is summarized below.
Figure: Cellular cost model
Point-to-point
The point-to-point model evaluates the feasibility of establishing radio links between points of interest (POIs) and cell sites using visibility analysis. This involves assessing whether the line of sight between a POI and a cell site is obstructed, ensuring that only feasible links are considered for deployment. The analysis uses open topography data from the Shuttle Radar Topography Mission (SRTM), which provides 30-meter resolution elevation data. The maximum visibility limit is set at 35 kilometers, meaning that cell sites beyond this distance are not considered visible or feasible for point-to-point connectivity.
Figure: Visible cell site
Figure: Obstructed cell site
Feasibility
Point-to-point microwave is considered a feasible technology for a POI if at least one cell site (or another POI) is visible from the POI.
Required data inputs
- Points of interest
- Cell sites
Model parameters
| Description | Example value |
|---|---|
| Bandwidth per access link (MHz) | 10 |
| Access link cost (USD per hop) | 831.59 |
| Annual hardware maintenance and replacement costs (USD per year, as a fraction of hardware CAPEX) | 0.004 |
| Access ISP fees (USD per Mbps per year) | 24 |
| Annual recurring license fee for 1MHz (USD per MHz per year) | 100 |
| Annual traffic fee (USD per Mbps per year) | 12 |
| Bandwidth per backhaul link (MHz) | 20 |
| Backhaul links (Links) | 0 |
| Backhaul links cost (USD per hop) | 2,825.07 |
| Hardware setup cost (USD per POI) | 500 |
| One time license fee for 1MHz (USD per MHz) | 500 |
| Reinvest into hardware after (Years) | 5 |
| Retransmission towers cost (USD per tower) | 13,000 |
| Retransmission towers (Towers) | 0 |
Cost model
The point-to-point cost model is summarized below. There are added complexities in this cost model due to the presence of additional physical infrastructure, such as retransmission towers and backhaul links - as well as additional one-time and annual license fees.
Figure: Point to point cost model
Satellite
There is no specific analysis used to assess the feasibility of satellite connections. They are considered always feasible in this version of the platform.
Feasibility
Satellite connections are always considered feasible.
Required data inputs
- Points of interest
Model parameters
| Description | Example value |
|---|---|
| Annual hardware maintenance and replacement costs (USD per year, as a fraction of hardware CAPEX) | 0.04 |
| Access ISP fees (USD per Mbps per year) | 24 |
| Annual traffic fee (USD per Mbps per year) | 12 |
| Hardware setup cost (USD per POI) | 3,000 |
| Reinvest into hardware after (Years) | 5 |
Cost model
The satellite cost model is summarized below.
Figure: Satellite cost model
