AT&T on their LTE Backhaul Architecture

Backhaul is a topic that may be giving some operators nightmare. Picked up this slightly old article from Light reading via WirelessMoves.

AT&T network architect Yiannis Argyropoulos addressed the Backhaul Strategies and Core Convergence for Mobile Operators event in New York City and had the following to say:

The lines between wireless and wireline networks are blurring, as are the boundaries between access and core networks, driven by the need to carry the flood of wireless data traffic more efficiently. AT&T is aggressively deploying fiber to its mobile cell sites and migrating from Sonet to Ethernet, but more changes will be needed. AT&T started its fiber push in 2008, and it will take at least seven years to complete, said Argyropoulos.

For the short term, today's metro Ethernet architecture will support LTE, but longer term, the network architecture needs to have less operational complexity, noted the AT&T man. The carrier is in the process of testing new approaches, based in part on work being done by 3rd Generation Partnership Project (3GPP) and the Broadband Forum .

AT&T also is looking for coordination of policy control between its wireline and wireless networks, so that the core network services are the same for end-users, regardless of how they connect to the network. It is no longer adequate for quality-of-service to be delivered piecemeal, within different segments of the network, Argyropoulos stated: "There is a lot of work going on right now to harmonize these."

The early 3GPP scheme for QoS on 3G UMTS networks was too complicated to be implemented, but newer LTE QoS plans from the 3GPP, with nine QoS classes and a smaller number of individual class attributes, look more practical.




The growing volume of data traffic is having an impact on other areas of the carrier's operations, too. The widespread use of bandwidth-hungry smartphone devices is creating new traffic patterns that, among other things, eliminate traditional maintenance windows traditionally scheduled in the early hours of weekend mornings, Argyropoulos pointed out.

"Data traffic peaks at the same time as voice, but it has multiple peaks, and it doesn't ever really subside," he said. That, in turn, is putting pressure on wireless network operators and their vendors to do hitless network upgrades and to build more resiliency into their networks.

AT&T is looking to other means of offloading traffic, including routing optimization that will use gateways strategically placed in the network to direct traffic onto the Internet, and not carry it through the metro and core networks first.

"Most of the mobile data traffic is coming from the Internet and going to the Internet."

It will also be important to offload subscriber traffic generated in the home onto a domestic Internet connection, he added.

To get an Idea of the mobile backhaul load, see my earlier post here.

Along with Fiber, Microwave is also an option and you can read more about it in Daily Wireless blog.

Also came across this blod dedicated to mobile backhaul, that is available here.