Cambium Networks

Wireless That Just Works


Making Citywide WiFi a Reality

By    October 2, 2015

Citizens are demanding WiFi connectivity. Politicians garner support in elections based on the promise of city wide WiFi. Despite that, it is very rare, for these promises to be met effectively. There are mainly three reasons:

  • Cost of deployment
  • Delay in deployment
  • Keeping the infrastructure functional after the commissioning

Let’s dive into each and understand further.

A. Cost of Deployment:

Cost of deployment consists of the following:

  1. Cost of the Access Point (AP) equipment
  2. Cost of the cable and associated labor to install the backhaul
  3. Cost of providing a power source

While equipment costs attract the most attention, the WiFi AP equipment cost is usually less than a third of the cost of the project.  City deployment AP features are very different than those needed for enterprise or industrial applications.  Many products in the market designed for industrial communications are either substandard in throughput or highly ruggedized and expensive. For public WiFi applications, throughput speed is of prime importance. Ruggedization is needed and an IP55 rated device meets the need. 

There are multiple options for the backhaul: fiber optic cable, wireless mesh and TDD Point-to-Multipoint (PMP). Cost of installing fiber cable is not only the largest contributor to the cost of deployment, but is an annoyance to the local citizens due to traffic disruption while digging while digging up roads.  The mesh wireless systems used to overcome this are marred with the problem of inefficiency and poor use of spectrum.  The TDD systems used in products like Cambium ePMP™ and PMP 450 provide the optimal solution to achieve wire like throughput.  

Once installed, wireless is also less susceptible to the physical damage that hinders wired and fiber infrastructure. In addition to the obvious physical damage caused by storms, accidents, theft, and inadvertent cut cables, there may be other unforeseen elements that can bring down a network. Local animals can pose a problem.  According to Down to Earth, a publication of the Centre for Science and Environment,  monkeys have derailed Prime Minister Narendra Modi's plans of making Varanasi city WiFi enabled by regularly chewing optical fiber cables. In Australia, special cables are required to protect networks from overly eager parrots [commonly referred to as cocky proofing by the Aussies]. The benefits of wireless solutions become obvious. Cambium’s WiFi solution that integrates with its wireless infrastructure solves this issue effectively.

In most cases the power source is available at the point of installation.  For locations such as parks, where power is not readily available, an access point with features such a scheduled time of operation reduces total energy usage, and are most suitable. This feature allows for energy to be sourced from a less expensive solar panel and battery backup solution.

B. Delay in deployment:

The time consumed in deployment can be divided into two sections:

  1. Providing backhaul for Wi-Fi access points
  2. Putting together backend controller and management system

First, when there is a wired network serving to backhaul the system, there is significant time consumed to trench and install cables.  A quicker alternative would be wireless backhaul.  While some have tried to accomplish this with mesh technology, these systems are constrained by self and external interference issues. In many cases, network operators have found that mesh systems require several months to tune and even then only achieve sub-par performance. We propose a TDD-based system such as Cambium's PMP 450 or ePMP.

Second, putting together the management, controller, authentication system and billing system is also a significant contributor to deployment delay. Purchasing software and hardware, creating or renting a data center to host them are non-trivial tasks.  This can be avoided by using an end-to-end management controller and management system that runs in cloud such as cnMaestro™.

C. Keeping the infrastructure functional: 

Frequently when a WiFi system is installed, it functions properly at the beginning, but performance degrades over time.  The connectivity that had started as the delight to customer becomes the reason for dissatisfaction with the network operators. 

A few things need to be considered to avoid such situations:

  1. The access point and wireless backbone system needs to be of high quality hardware that does not breakdown under dust and rain and electric surge. 
  2. A management system should not only provide end to end troubleshooting, which is not only quick to identify the problem, but should also be easy enough that an RF and a security expert is not needed.  Cambium’s cnMaestro meets such needs very cost effectively.
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