How Cradlepoint problem solvers built a new generation of ruggedized, mobile routers from the ground up
On the surface, it may seem like the simplest things are the easiest to understand. But upon closer examination, it becomes apparent that these seemingly uncomplicated things are actually quite complex. Whether it’s the workings of our own bodies, the mechanics of an engine, or the intricacies of an ecosystem, there is often much more than meets the eye.
The R2100 Series 5G Ruggedized Router is no different. What began as a basic concept led to a development process that was anything but simple. Let’s dive into the journey that resulted in Cradlepoint’s first-ever router on the roof.
Cutting the cables: A new approach to vehicle routers
The making of the R2100 Series rooftop router was born from real-life installation pain points, including a problem that every vehicle router faces: too many cables and not enough room.
Police cars, ambulances, buses, and more, use radio frequencies (RF) to receive and transmit messages, broadcast alarms, and coordinate activities. Each RF interface requires a coaxial cable to transmit the signal from the router — likely located under a seat or in the trunk — through a conduit, to a rooftop antenna where it can gain a clear line of sight to the sky. For some routers, this bundle can include 10 or more cables routed through the vehicle, with even more accompanying the adoption of 5G.
Seeing the trouble this caused first responders and public service agencies, Cradlepoint engineers began to workshop how to effectively combine the router and antenna into a single unit that could be mounted to the top of a vehicle, ultimately reducing the number of cables to just one power or power over Ethernet (PoE) cable.
Building a router with enclosed antennas was an unprecedented challenge. The team began by designing an antenna array, which grouped multiple antennas together to form a single, larger antenna to transmit and receive radio waves. This eliminated the need for coaxial cables and allowed the unit to be powered over Ethernet.
The engineers then needed a way to house not only the cellular, Wi-Fi, and GPS/GNSS antennas, but also the active, radio-emitting electronics. The solution had to optimize space while successfully balancing aerodynamics, aesthetics, and functionality. The final result was far from the traditional pizza-box-shaped electronic casing. Instead, it resembled something more like a shark fin.
Adding another layer of innovation to the R2100
The “fin” set the stage for captive Wi-Fi — a first-of-its-kind feature in which certain R2100 Series routers can be connected to a qualified in-vehicle router such as the R1900 to share key configurations on a single NetCloud Manager license, while boosting Wi-Fi reach from the roof. Perfecting captive Wi-Fi came with its own set of challenges, however.
With an R1900 acting as a controller inside the vehicle and the R2100 in close proximity on the roof, there was a risk of Wi-Fi channels overlapping, which can create a poor user experience. Engineers were tasked with creating a unique set of code to ensure the router on the roof occupied a unique Wi-Fi channel even when sharing configurations with the controller. This creative problem solving was also put to use when coding synchronization solutions for regulatory regions and security certificates.
Things begin to heat up for the router on the roof
After finalizing the easy-to-install physical design, space-saving circuitry, and internal configurations, it was time to address environmental challenges, beginning with thermal obstacles.
Cradlepoint routers are passively cooled, meaning they dissipate heat via natural convection and conductive heat transfer rather than using fans to reduce internal operating temperatures. In a small space, passive cooling is difficult. When attached to the roof of a vehicle, cooling the router becomes increasingly complicated due to the increase in temperature caused by the absorption of heat on a dark surface, also known as solar loading.
“Putting the device on the vehicle opened us up to the elements and the team went so far as to research extreme high and low temperature regions across the globe to make sure the device would work, even in the harshest environments,” said Jake Smith, lead product manager at Cradlepoint.
Through careful material selection and meticulous testing, the final R2100 form factor could withstand a broad operating temperature range of -30 ºC to 70 ºC (-22 ºF to 158 ºF).
Earning the title of ruggedized router
Outsmarting the sun was one hurdle cleared, but what about the other ways a rooftop router might encounter harm? From rainstorms to car washes to miscellaneous impacts, the R2100 Series had to withstand more than a pleasant spring day to be an effective solution for its target audience. That’s where the IK Code comes in.
The IK Code is an international impact rating that signifies how well an enclosure protects its internal parts against external impacts. The more force the enclosure can withstand, the higher its rating. Following a series of tests, the R2100 achieved an IK 10 — the highest rating — on nearly all of its surfaces. The only exception was the top of the router, which was rated IK 9, making the router remarkably strong overall.
In one test of strength, Cradlepoint partners rode piggyback on one another to simulate the weight of an average American firefighter in full gear. Then, they kicked, jumped, and stomped on the router to mimic the potential impacts an R2100 mounted to the roof of a fire engine might encounter. Spoiler alert: it held up.
This tough-as-nails router has also achieved an ingress protection (IP) rating of IP67, meaning it is sufficiently protected against vibrations, dust, airborne particles, water, and other liquids, including immersion in up to 1 meter of water.
“Our lead product manager volunteered his vehicle at one point,” said Steve Howarth, vice president of engineering at Cradlepoint. “We cut a hole in it, mounted a prototype to the top and took it through the car wash a handful of times. It was a great way to test the installation integrity.”
Putting it all together
While thermal considerations and an industrial design are key to a successful router concept, minimizing noise while maximizing signal transmission is vital. Housing the antenna array in a tight space with active noise-emitting electronics is a fine balance, as too much noise at the router level will interfere with the ability to transmit and receive signals from the cellular network. The R2100 Series checks that box and more.
Surpassing industry standards for durability, reliability, and enterprise-class security, this highly differentiated router on the roof delivers the performance and simplicity organizations need to spearhead the digital transformation of fleet vehicles.