Dancing with the Small Cell Stars
Integrating these different radio access technologies into a single platform or node provides big value, such as greater densification and a broader set of services then either technology could provide on its own.
- exactly how do these two functions converge into a single unit?
- what about site aquisition?
- what does that access points actually look like?
While mobile operators are rushing Wi-Fi to address their capacity needs in very high-density (primarily) indoor locations, small cells are also viewed as a good way to boost cellular densification in high traffic outdoors areas. But is it really that black and white?
Deploying a multi-RAN access points outdoors is typically much more challenging than deploying Wi-Fi indoors. Why? Because power and backhaul (fiber, microwave or spectrum) is scarce, costly and cumbersome to provision - needlessly stretching out deployment schedules. And in both cases, there is a requirement to get permission to install equipment from the entity that controls the site.
Some of the very best places to mount small cells are on street furniture, specifically traffic lights and light poles (see picture below). These are highly desirable locations because they are almost everywhere and come with AC power. However, they almost never have Ethernet or some fiber connection for backhauling traffic.
This introduces the potential for Wi-Fi APs to backhaul small cell traffic to a "wired" aggression point in close proximity. That addresses the first challenge with many outdoor small cell deployments, but certainly not the last.
- It usually starts with a neutral host solution where a single operator is allowed onto their light poles and they must provide services for everyone. Municipalities don't want a lot of clutter on their light poles. Wi-Fi excels at providing a neutral host solution. Services can be "free" to all users, operators can wholesale services to other operators, or Hotspot 2.0 can be used to enable roaming on that infrastructure.
- It usually ends with aesthetics. How these devices look in the environment is a huge concern for many cities, stadiums and public venues. This is driven by the desire to, again, limit clutter. Consequently there is a premium on putting "everything" into one box. Everything means the small cell radio, the Wi-Fi radio for neutral host, and the wireless backhaul solution.
This suggests an approach that allows the mobile operator to lead with a Wi-Fi on the street furniture, as it is just easier to get that approved by the various municipalities that control access to these poles, and then add small cells where and when needed to further increase cellular densification.
Another even more intriguing options is to have a 3rd party deploy the Wi-Fi APs and then lease space on the back of these APs to different mobile operators - effectively segregating and wholesaling wireless capacity. Small cells have much greater range than Wi-Fi APs, and could thus support an interleaving of small cell services from different MNOs on the same Wi-Fi footprint.
Most mobile operators are moving to a model that gives them the most flexibility such as deploying devices that provide mechanical separation of the Wi-Fi APs and small cells. This ensures "flexible deployment options" as these units can effectively evolve at their own pace. And as faster 802.11ac radios emerge, they can be easily integrated into a multi-RAN node with virtually no impact to the small cell. And the converse is true. As small cells are enhanced they don't impact the Wi-Fi AP. It also makes it very easy for a 3rd party to deploy the Wi-Fi footprint and lease space on the back of these AP's to different MNOs that might use small cells from different RAN vendors. The small cell bolts onto the back of the Wi-Fi AP and gets power and backhaul from the unit. The Ruckus SmartCell 8800 (above) is just one example of this new category of the multi-access RAN nodes.
Ultimately the convergence of Wi-Fi and small cells is a very compelling idea with lots of industry momentum, but it is probably best if Wi-Fi leads in this dance.