In 2016, there are still just a handful of services which are deemed crucial to a thriving community — running water, housing and electricity being amongst them. However, with the growing need and benefits of the Internet, our idea of what constitutes an ‘essential’ utility has had to expand.

In its National Development Plan 2030, the government of South Africa stated that it wants universally available Internet across the country in 14 years’ time.

We all understand the value of Internet connectivity especially in terms of educational benefits, improved healthcare services, better opportunities for economic development and of course, social cohesion. From that perspective, it is critical to connect the country sooner rather than later.

In 2013, a bid to connect every citizen was launched across the city of Tshwane. To date, 850 Free Internet Zones (FIZs) have been installed in the local area and almost two million unique users have been accessing the web since November of 2013. By 2018, Tshwane will have Wi-Fi within walking distance of every citizen.

In this article, we will take a look at the four proven techniques to successfully deploy Wi-Fi across community: 

1.THE WI-FI CANOPY

This technology applies when the coverage area is small (less than 2km in diameter). One approach is to deploy Wi-Fi Access Points (AP) throughout the community, but this implementation requires providing backhaul to these APs. A wired backhaul solution deployment can be expensive and time-consuming, and wireless backhaul consumes scarce wireless spectrum. Alternately, if an elevated, centrally located mounting site exists – a tower, high-rise building, or pole – Wi-Fi APs can be positioned about 20 feet higher than rest of the community, but a much more efficient solution is to install three dual-band Wi-Fi APs with 120º sector antennas in a central location.

The three APs should each use different, non-overlapping channels (recall that only three non-overlapping channels exist in 2.4 GHz). For this type of deployment, 21 dBm transmit power and a 15 dBi antenna gain would give optimum results (assuming that the EIRP limits are around 36 dBm, which is true of most regions). In general, always prioritize lower transmit power and higher gain antennas because the connecting devices have very low transmit power.

2. POINT TO MULTIPOINT (PMP) BACKHAUL

This strategy is applicable for a larger community (spanning around 3-10km). In this case, a tower, high rise building, or hill can be used to deploy Point to Multipoint APs. These PMP Access Points wirelessly connect to subscriber modules (SM) deployed at the installation site of the Wi-Fi hotspot. Each Wi-Fi AP is installed on or adjacent to the same pole as its paired PMP SM.

In these cases, network designers should ensure the following:

• One management system (controller) should manage both the PMP system and Wi-Fi APs.

• The PMP system should be based on Time Division Multiple Access (TDMA) technology rather than commercial Wi-Fi, to ensure reliable and deterministic backhaul.

• The PMP system should be capable of high throughput, possible with such techniques as Massive MU-MIMO when the deployment includes more than thirty Wi-Fi hotspots.

• The Wi-Fi AP should have a second Ethernet port that can supply power to a connected PMP SM.

Running two power cables per location for each of the Wi-Fi AP and the PMP SM streamlines deployment.

3. POINT TO POINT (PTP) BACKHAUL FOR A LONG SPAN

This technique is ideal for deploying long-distance Wi-Fi along a road, railway line, or beach.

In these cases, network designers should ensure that

• One management system (controller) should manage both the PTP system and Wi-Fi APs.

• The PTP system should be based on TDMA technology to provide reliable and deterministic backhaul.

• The PTP antenna should form a narrow beam to reduce interference and increase range.

• The PTP antennas should have good front to back ratio to avoid self-interference.

• Alternating links should use two different channels.

• As in the PMP case, the Wi-Fi access point should have a second Ethernet port that can supply power to a connected PMP SM. Running two power cables per location for each of the Wi-Fi AP and the PMP SM streamlines deployment.

4. WI-FI MESH

The appeal of a Wi-Fi Mesh configuration is the use of the same technology as Wi-Fi APs to talk to wireless clients. However, limitations of this implementation include vulnerability to external and self-interference when mesh APs use omnidirectional antennas. As backhaul and access share the same radio, each hop decreases available throughput and increases latency, limiting total system scalability to two hops. That being said, Wi-Fi mesh configurations can provide adequate performance conveniently in some cases. For instance, the mesh technique easily extends the primary coverage to other small areas without available wire, such as a restaurant patio.

An extended deployment requires combining the above techniques, which compounds the importance of a centralized management system that deploys, manages and troubleshoots the equipment used in all the above scenarios.