Call for consensus on small cell base stations

October 04, 2012 // By Rick Merritt
Wireless carriers know they need a new tier of small cell base stations to keep pace with the explosive growth in mobile data. But they are still working toward a clear consensus on issues such as how they will be deployed and interact with the rest of the cellular network.

That’s the view of Gordon Mansfield, the new chairman of the Small Cell Forum. Mansfield has a keen view of what carriers need because he is one as executive director of small cell solutions and radio access network delivery at AT&T Mobility.

"We have to get consensus in the operator community about what we need [in small cells], and we are very close--then we need to get the full [vendor] ecosystem behind it," said Mansfield.

Small cells consist of at least three classes of new systems emerging beneath the traditional boxes now dubbed macro base stations. Mansfield splits small cells into three buckets:

  1. Femto cells consume roughly 250 milliwatts and serve about four residential users.
  2. Pico cells consume 1W, serve 16-64 users and are typically placed indoors.
  3. Micro cells consume about 5W, serve hundreds of users and are generally placed outdoors.

Carriers have conducted separate trials of 3G and LTE small cells with generally favorable results. Next year they start hybrid trials that mix 3G, LTE and Wi-Fi systems.

"That’s when we will start to assess if its manageable to put these systems together given we have largely solved the LTE and 3G issues separately. I personally think the answer to that question is yes," he said.

The trials seek optimal ways to reduce interference and link the small cells to the macro base station networks.

The Forum also aims to help provide clarity about how the small cells will link to core networks. A wide variety of so-called backhaul options are currently in use including fibre optic links, dedicated and best-efforts Ethernet, multiple classes of microwave connections and even Wi-Fi.

Carriers also face regulatory issues as they seek approvals to place them from everyone from corner café owners to federal governments. Issues are sometimes as basic "as powering boxes in locations where you want them," Mansfield said.

The creation of the Small Cell Forum mirrors the growing awareness of