This article originally appeared in the November 2010 issue of NGN.

Despite investment from mobile operators to shore up their broadband networks against the increasing tide of data, the experience of their subscribers suggests that the effort has only been partly successful.

Popular devices such as the Android smartphones, the BlackBerry (News - Alert), iPhone and iPad have driven a dramatic increase in the number of data sessions in mobile networks, with greater than 10 times the normal number of session attempts relative to voice-only handsets.

Some operators have reported an annual doubling of data traffic, leading to usage caps and other schemes designed to protect their networks, but which reduce the subscriber experience during activity peaks.

This is most apparent at the radio access network, where the cost of upgrading the mobile backhaul network is often the most expensive. The RAN and the attendant backhaul access require significant opex and capex to accommodate the rising bandwidth needs to the base stations over leased lines (E1/T1), microwave, metro Ethernet or fiber connections. In many operators the backhaul represents more than 20 percent of opex and a significant portion of the annual capex.

 Operators have many other demands placed on their network upgrade budgets with the advent of femtocells, LTE (News - Alert) and other technologies, further amplifying the challenge. But our research shows that as mobile video traffic grows, we are reaching a tipping point at which the network fails to handle effectively traffic peaks in the RAN, and subscribers receive pixilated or jerky video, at best.

This is because peaks are difficult to predict and can be generated by any number of different network events, including mobile videos that go viral and receive a huge surge in interest and corresponding requests for the network to serve up thousands of video streams in parallel. Or, subscribers could be using the network to upgrade to the latest device software version, thereby causing a bottleneck as they all seek to do so simultaneously. Such flash events can be four or five times the regular baseline of traffic, which makes it a very difficult job of dimensioning the network to perform optimally. In economic terms, dimensioning the network to a capacity level where all peaks can be handled is prohibitive, but unfortunately, it only takes a few poor experiences to persuade subscribers to try a new network provider.

This dilemma has had operators scratching their heads. On the one hand, the influx in data traffic - if properly monetized – is welcome and also deserving of network upgrades so that subscribers can continue to get more from their service; on the other, it’s an expensive and sophisticated task to upgrade the RAN at a time when so many other areas of the network are suffering too.

Currently, they have three options, none of which are ideal:

-Add capacity to the existing backhaul network through additional leased lines or TDM microwave capacity to the cell site<bold>

This is often the quickest and easiest to accomplish operationally, but it can also be the most expensive, as it does not fundamentally change the economics.

-Upgrade to packet-based backhaul<bold>

This approach needs significant planning, time, and capital investment in the areas of major network equipment, rights-of-way agreements, spectrum leasing, and operational upgrades that can also incur significant time.

-Offload and divert certain backhaul traffic<bold>

This approach can be effective but has economic, operational, spectrum planning, policy and service level agreement implications.

We believe the most cost-effective and rapid method for dealing with the data explosion in the backhaul network will not come from conventional solutions; it will come from innovation and a fresh approach to the problem.

Based on our deep experience with mobile data networks, a new method for optimizing the content that traverses the RAN has been developed. Unlike other content optimization techniques such as encoding or compression, the new solution delivers a lossless experience to subscribers, which helps operators deliver superb quality video and application performance while reducing traffic by up to 90 percent during peak congestion periods.

Adaptive content optimization provides operators with three ways to optimize their investments while easing the transition to the next generation of infrastructure that comes with LTE. First, It reduces congestion and improves user experience across a full range of mobile broadband content and applications including IP video and Internet content. Secondly, it is architected for HSPA radio networks – the largest deployed technology for mobile broadband. Finally, the technology is scalable to support LTE, so existing HSPA sites can be combined efficiently with LTE radio deployments as they are rolled out.

ACO acts as a shock absorber in the network that cushions existing assets against the influx of data traffic while allowing the network to scale to continue to meet future demands. It applies patent-pending, advanced data optimization techniques and adaptive learning algorithms in real-time, providing operators with a way to re-balance their service delivery economics in line with revenue growth – not traffic growth.

Scott Hilton (News - Alert) is vice president and general manager of broadband optimization solutions at Sycamore Networks.