What is "Point to Point" or "Line of Sight" WiFi?
Line of sight WiFi is exactly what it sounds like: long-range wireless bridging that requires a clear line of sign (no obstructions) to operate. Line of sight systems are significantly cheaper when compared to solutions like TVWS, but operate at shorter distances, and require flat terrain with as few obstructions as possible between locations.
How does "Point to Point" or "Line of Sight" WiFi work?
Bridge devices are placed at each location and lined up to point directly at each other. This may require a tall pole or roof-mount solution to ensure there are no obstructions, and the devices must be angled to point directly at each other for best speeds. A benefit of line of sight WiFi is that throughput can be extremely high, in excess of 1 Gbps.
Frequency of P2P/LoS equipment:
P2P/LoS equipment operates on a wide range of frequencies requiring different mounting heights or licensing requirements, and providing different speeds and maximum distances. Generally:
2.4 GHz allows a longer distance link (~15km max), with the slowest speeds (~175 Mbps max). 2.4 GHz is very congested so may only be an option in rural areas.
5 GHz provides a slightly shorter distance (~12km max), with close to gigabit speeds (~750 Mbps). 5 GHz is less congested but may be an issue in high density areas.
60 GHz has a much shorter range (~1.5km max), but manages incredible speeds (~5 Gbps). 60 GHz may require licensing for use.
How does this work with E-Rate?
E-Rate allows for wireless within the borders of your library property. When you share your connection "beyond the walls" of you library, E-Rate cannot be used to cover that portion of your internet. To resolve this issue, we recommend dedicating a percentage of your internet connection to solutions outside of your library, and requesting e-rate reimbursement for only the percentage that stays within your library. For example: Library A has 100 Mbps of internet speed at their branch. The library sets up external WiFi and dedicates 20 Mbps of that connection (20%) to support their new WiFi infrastructure. They then change their E-rate reimbursement request to only ask for 80% of their total internet bill -- the portion that stays at their library -- and pay out of pocket for the 20% that is dedicated to supporting the external connection. See example here.
Examples of "Point to Point" or "Line of Sight" hardware:
Planning your setup:
Planning an Outdoor Wireless Link (Ubiquity)
Which Product Should I Use? (Ubiquity)