In his keynote address here, Argyropoulos, a member of AT&T's Architecture & Planning team, said he expects to see significant innovations in small cell installation, power and cost issues, and major decisions regarding backhaul methods and network architectures, all potentially in the next year to 18 months.
Other basic issues, including the business model for small cells and even who will build out these networks, must still be resolved, says Patrick Donegan, Heavy Reading senior analyst. In some instances, he says, vendors are "tearing their hair out" trying to get a clear lead from their service provider customers as to what they want.
"They want a lot of everything, but they are not putting forth a lot of large orders on anything," Donegan noted. It's not even clear if service providers want to build out small cells themselves and maintain their own separate facilities, or look to wholesale operators to build these facilities for them.
Other challenges include:
- Backhaul for the final 100 yards: Microwave is one of multiple radio technology options, but choices include line of sight and non-line of sight, and there are advantages and disadvantages to each that may require field deployment and testing to resolve.
- Management of a large volume of small cells: Small cells have been around for a long time, but weren't widely used because managing users moving from the macro network to the small cell network generated massive signaling and handover issues. LTE promises to automate this process, and 3GPP has developed APIs to enable that, but none of that has happened yet at scale, noted Argyropoulos, and until it does, uncertainty remains.
- Small cell architecture: The 3GPP specs require using IPSec for security over an unmanaged Internet access link, but that will drive up costs and eat into latency budgets for small cells, Donegan points out. AT&T is looking at using Metro Ethernet connections so that IPSec isn't required and a lower-level security protocol will suffice.
- Cookie-cutter installation requirements: For small cells to enable greater coverage density cost-effectively, they must be easily installed in massive quantities without having to tailor each installation for a wide variety of field conditions. AT&T is looking to its vendors for innovation to make that happen, stated Argyropoulos.
"A lot of strategy will be dependent on field realities, he says. "There is a lot of room for innovation for the next year or more -- maybe longer -- for small cells, regarding installation, backhaul services and power. All of this is still being discussed and decided -- there haven't been major decisions made but you will see a lot of activity over the next year or so."
— Carol Wilson, Chief Editor, Events, Light Reading