Automation is a growing theme for many aspects of life today. Many of the manual and even highly skilled processes of the past are being superseded by alternative, innovative methods. Recently, I visited CommScope’s R&D lab at Chelmsford, near Boston, and saw for myself how they’ve pioneered using an autonomous robot to walk their building and conduct extensive wireless performance testing.
Robot applications growing in scope
The Sci-Fi vision of humanoid robots is thankfully still quite some time off, although I heard of “PiBots” being developed to fly aircraft. Uber has a vision of self-driving cars, replacing the need to buy your own.
Meanwhile, several simpler more mundane robot applications are already mainstream. Automated lawn mowers and domestic vacuum cleaners are good examples of repeatable, relatively mundane tasks for which robots are suitable.
Jay Weitzen, CommScope’s director of RAN performance and analytics for small cells, wanted to enhance their ongoing product testing by making large numbers of repeatable RF measurements throughout a real office building to assess and verify small cell performance.
For this mission, Jay’s team decided to enlist robotic help. They selected the TurtleBot open-source platform. It resembles a domestic vacuum cleaner robot with a similar footprint but larger height, to accommodate connected equipment and sensors, and a software development kit that supports extensive control and customisation. It is managed by an on-board laptop connected to a laser rangefinder, internal gyroscope and wheel odometry that together track its position accurately to within a foot at all times. This system navigates around the rooms, discovering and exploring according to how it has been pre-configured.
A second on-board laptop connects to one or more UEs (smartphone devices) that conduct extensive RF measurements and simulate specific scenarios during the tests.
A custom designed post-processing application analyses data from both and reports results.
The operational area includes any accessible floor space including underneath desks, inside meeting rooms, offices, cubes and open spaces. While it can’t open doors, it knows its limits and is smart enough not to fall down the stairs. The test area can be mapped against a floorplan diagram for reporting purposes.
Weitzen explained: “Unlike manual walk testing, the procedure is extremely thorough and includes every accessible area. It’s repeatable, so subsequent software releases can be thoroughly regression-tested against previous results. SON and handover testing can be methodical and repeatedly tested with different configurations.” He added that “Robots don’t get tired, bored or sick and are very good at otherwise monotonous, repeated activities.”
The level of detail from such extensive in-building testing is impressive. What CommScope engineers look for are not just signal strength levels, but signal quality, especially at cell edge boundaries covered by adjacent radio nodes.
Although there are three radio nodes covering the floor of their building, each smartphone only sees one common physical cell ID (hence the name OneCell). The chart below shows the continuity and thorough signal coverage, with the brown areas illustrating a separate signal emulating an outdoor macrocell for use when leaving/entering the building.
Signal quality is arguably even more important, and the chart below shows the extremely high signal/noise ratio: 20 dB or greater across 95% of test locations. This leads to extremely high throughput because very high modulation rates can be used. The system achieves high quality service throughout, with Channel Quality Index of 11 or greater (out of a possible 15) in 95% of test locations. This provides all users with the maximum throughput rates that LTE offers – and even more with cell virtualisation. [See sidebar on right hand side: Cell Virtualisation in Action]
Innovation comes in many shapes and forms.
CommScope has pioneered an effective method of thoroughly walk-testing their in-building small cell system. While not required for use in every real-world commercial deployment, it serves an important purpose to validate and verify technical performance.
While I don’t believe that on-site installers have too much to worry about with robots replacing their job roles, it does indirectly improve the sophistication of in-building solutions and ensures the system is robust and resilient.