There has always been industry interest in somehow leveraging the distributed enterprise WLAN to remedy the problem of poor in-building cell coverage, but past attempts have never really gotten off the ground. Ruckus Wireless has introduced a new technology that leverages fresh spectrum, and this architecture looks promising.
Considering that most in-building mobile signal problems tend to happen in large buildings where WiFi networks are deployed, it’s natural to look at the distributed nature of the WLAN as a potential avenue for relief by bringing the outside carrier networks in. Cisco tried it with add-on mobile network radio modules for its higher end APs. But in Cisco’s case, the radios were single-carrier only, and the back end was fairly complicated and required Verizon or AT&T collaboration to work. The modules weren't a bad idea, but they were expensive and beyond the capabilities of most WLAN installers.
Ruckus addresses the problem by leveraging a new technology called Citizens Broadband Radio Service (CBRS) in the 3.5 GHz spectrum for its OpenG technology. A little background on CBRS: Most of us design our wireless LAN environments for excellent performance on 5 GHz. This generally means the lower 2.4 GHz side of dual-band access points will also be adequate because the lower frequency propagates farther. CBRS falls between both current WiFi bands, and will soon be available as part of multi-radio WLAN access points or stand-alone PoE-powered CBRS nodes.
Each Ruckus OpenG node will support between 32 and 64 mobile clients while covering up to 10,000 feet, and traffic will ride the same local Ethernet distribution network that the WLAN uses. The back-end used by OpenG to get each subscriber’s voice traffic to the right carrier will be hosted locally or in the cloud, and there’s not a lot to the technology that requires specialized expertise. OpenG is essentially a parallel offering to the WLAN, and is actually wireless vendor-agnostic so it can also be used in non-Ruckus environments. If it works as Ruckus hopes, CBRS will be a game changer.
While there are some early CBRS client devices out in the market periphery, Ruckus expects 3.5 GHz radios to become common in new devices later this year. There is 150 MHz of discreet spectrum allotted for CBRS channels, and each node will check in to an FCC-administered database where -- to oversimplify a bit -- channel coordination happens automatically and without installer intervention.
Ruckus expects some sort of visibility into the on premise OpenG environment by carriers, but I didn’t get details on what a CBRS management portal might amount to during my briefing. As with many legacy distributed antenna solutions, CBRS is considered a “neutral-host solution” for its ability to front end multiple carriers using the common 3.5 GHz spectrum.
With Qualcomm, Ruckus is demonstrating OpenG at the 2016 Mobile World Congress, and given the FCC’s backing of CBRS, it stands to reason that other enterprise WLAN vendors will announce similar technologies in the near future. Though it’s still a little murky how other carrier initiatives like LTE-U will ultimately impact WiFi, the advent of CBRS makes it clear that things are starting to move here. CBRS could play a huge role in alleviating in-building cellular issues as an easy all-carrier add-on to the WLAN, and that has been a long time in coming.