AT&T to Deploy 40,000 Small Cells as Part of Move to "Heterogeneous Network"

As part of Project VIP, AT&T’s network upgrade program, AT&T also plans to deploy more than 40,000 small cells by the end of 2015, creating a denser mobile network better able to handle data traffic demand in dense or urban areas.

Project Velocity IP (or Project VIP) is a three year, $14 billion investment plan to enhance AT&T’s mobile and fixed network IP broadband networks.

Between 2007 and 2012, mobile data traffic on AT&T’s network has increased more than 30,000 percent, AT&T says.

AT&T furthermore is working on the next generation of small cell technology, such as multi-standard “metrocells” that will support 3G, 4G LTE and Wi-Fi air interfaces.

Most observers would agree that end user demand for mobile network capacity is going to grow exponentially over the next decade, while even Long Term Evolution provides only incremental bandwidth gains.

Many would suggest several simultaneous solutions must be embraced, ranging from new spectrum to better coding, more efficient air interfaces, new spectrum, shared spectrum, small cell and virtualized architectures and use of unlicensed spectrum and Wi-Fi. In all likelihood, all will play a part in creating new networks.

Mobile analyst Monica Paolini, Senza Fili Consulting principal, argues for an “all of the above” definition of “heterogeneous networks.” Paolini says all air interfaces (GSM, CDMA, UMTS, HSPA, HSPA+, 4G: LTE, LTE-Advanced and Wi-Fi will be parts of the heterogeneous network, though not all will be used by every network.

Radio architectures will include macrocells as well as small cells (pico, femto, Wi-Fi or personal area), as well as distributed antenna systems.

Heterogeneous networks will span Indoor and outdoor locations; public, enterprise and residential locations.

All of that explains why many observers now say a future “fifth generation network” will not be distinguished from 4G strictly by air interface, bandwidth or frequency, but by the integration of many different architectures, protocols, networks, air interfaces and network ownership patterns.

In essence, network access for end user devices will be assembled dynamically, which explains the interest in “self organizing networks” able to provide access to any available network, in real time, often using the best available network.

Paolini says most of the adaptation will be an overlay of sorts, with mobile service providers incorporating new small cells, carrier Wi-Fi or other techniques first in dense urban areas where data demand is greatest.

By definition, frequency planning and interference control issues will grow as smaller cells are activated. Also, by definition, call control, data access and handoff chores will become more complex as users move into and out of small cell coverage areas and across access networks.

“Different radio technologies manage interference differently, and so the same small-cell

location may work for an LTE-Advanced small cell with sophisticated interference

mitigation techniques and not for a 3G small cell,” says Paolini.

In fact, the limited ability to manage interference in 3G environments is often cited as a cause for mobile operators’ hesitance to deploy 3G small cells.

Also, for the first time, frequency planning and interference avoidance will have to account for cells that are separately vertically, not just horizontally. So floor location within a single building now matters.

Use of Wi-Fi networks owned by third parties is the best example of how mobile networks are becoming heterogeneous. But small cells represent a next step, as well. Radio sites supporting multiple air interfaces are another example.