Reader Forum: Cell awareness an effective alternative to costly mobile backhaul

Editor’s Ntoe: Welcome to our weekly Reader Forum section. In an attempt to broaden our interaction with our readers we have created this forum for those with something meaningful to say to the wireless industry. We want to keep this as open as possible, but maintain some editorial control so as to keep it free of commercials or attacks. Please send along submissions for this section to our editors at: [email protected] [email protected].
I recently heard a comment by a veteran mobile engineer who said, “In the old days our understanding was that the more traffic we had on our network the more money we were making. Nowadays with the impact of the Internet and over-the-top applications, this no longer holds true. It’s a different ball game. Our network is transporting more and more data traffic, but we’re not earning any more money for it.”
Mobile networks that were built primarily for voice traffic are now feeling the strain from data traffic. Data inherently requires significantly more resources (both radio spectrum and backhaul capacity) than voice. Moreover, the variety of applications and content has changed dramatically even over the last couple of years – in terms of volume, richness and diversity. Some applications are bandwidth hogs, some are highly sensitive to jitter and delay, and some are simple and can perform pretty well under most conditions. Whatever the technical requirements, mobile subscribers expect their Internet applications and services to be accessible and to perform on demand. The massive move toward personalization of content and applications will only magnify these expectations.
This rising wave of mobile data traffic is a major source of concern for mobile operators. First, because they haven’t quite figured out how to turn increasing volumes of mobile data traffic into revenue. Second, because all that traffic is clogging up the network and affecting service reliability and performance. Part of the problem is that current 3/3.5G mobile network topologies have inherent bottlenecks within their architecture. The cell and its backhaul are particularly problematic. Numerous mobile broadband providers cite cell congestion as one of their biggest headaches that needs a solution right now! The urgency is real as new devices and applications, such as Apple’s iPad, ratchet mobile data demand up another notch. Just think — in 28 days, Apple sold 1 million iPads and users downloaded more than 12 million apps from the App Store.
Cells can become congested not only in the radio network (signaling overhead congestion) but also on the backhaul link (data). In today’s 3/3.5G mobile networks, cell backhaul is still based primarily on E1/T1 technology. Backhaul infrastructure that could once support over 100 simultaneous voices calls with ease can now be overloaded by a couple of iPhones and netbook users. If mobile operators are going to maximize their infrastructure investments and maintain some sort of control on capex, they need to deal with this issue sooner rather than later.
A number of solutions have been proposed by the industry to alleviate backhaul congestion—things like Wi-Fi offload, femtocells and backhaul bonding spring to mind. These options are workarounds rather than solutions because essentially, they move the problem somewhere else in the network or to someone else’s network. While some of these “band-aid” measures may provide temporary relief, they’re being implemented blindly today. The operator still doesn’t really know what’s causing the congestion. Moreover, the band-aids come with a price tag that eventually will have to be passed on to the consumer. Better to solve the problem at its source by managing data traffic so it doesn’t overwhelm the available bandwidth.
Even so, many operators are thinking about implementing these short-term solutions to tide them over until LTE is ready and they won’t need to worry about the cell backhaul anymore. While LTE promises to solve issues in the last mile, it will inevitably also move the bottleneck to somewhere else in the network. Operators will still have infrastructure limitations and they will still need to understand what’s causing the congestion. Better to solve today’s congestion problems with a solution that will be viable in the operator’s LTE network as well.
Just as their fixed-line counterparts have discovered, the key to managing the utilization of mobile data bandwidth is first and foremost to get a clear picture of what is happening on the network. Operators need to begin with a complete understanding of the type, volume, and behavior of traffic going over their backhaul. And since congestion “moves around” in the mobile network, it is essential for operators to have complete and real-time visibility down to the individual cell level, or in other words, “cell awareness.”
Cell awareness enables operators to understand the who, what and where of mobile data consumption, so they can make informed commercial decisions on how to handle traffic problems based on accurate usage statistics. With cell awareness, mobile operators can monitor and manage the bandwidth utilization of cell and cell backhaul resources with pinpoint accuracy. For example, cell awareness means that the operator will be able to find out that the recurring congestion on a particular cell backhaul is being caused by a voracious BitTorrent subscriber whose laptop is downloading large files all day. Or that a momentary service outage was caused by a stadium of football fans who were viewing the instant replay of a controversial call on their mobile phones. The need for cell-aware traffic management was reinforced by a major American infrastructure provider that recently voiced concerns that this kind of activity, left unmanaged, could potentially wipe out cell service in whole neighborhoods.
With cell-aware monitoring and traffic management capabilities, mobile operators know precisely where the network is congested, and which subscribers and applications are generating the traffic. Armed with that valuable knowledge, they can take more effective and long-lasting steps to control congestion, ensure fair use and deliver quality of experience to mobile data users.
But that’s not all.
Once mobile operators get cell congestion under control, they can focus on revenue opportunities. The same granular traffic statistics that provide a “cell-aware” view of utilization can also be used to better understand and fulfill market demands. As the old adage goes, “knowledge is power.” If you can zero in on an overloaded cell and see that two P2P downloaders and three streaming video sessions are eating up the bandwidth and causing quality of service issues for 20 other subscribers in that cell, what would you do?
While mobile operators in different regions around the world may have different answers to that question, having a complete understanding of what is going on their network empowers them with a choice about which approach to take. Some operators are implementing a fair-use approach to backhaul bandwidth — meaning that everyone in the cell at any given moment gets an equal share of the available bandwidth. Other operators are taking a more sophisticated “tiering” approach based on subscriber profiles (business, professional, youth, etc) or the needs of the application (i.e., delay-sensitive video or VoIP versus large-file downloads that aren’t affected by jitter or delay). While the tiering approach is effective at providing fair access and preventing congestion on the network, it also can lead to a win/win for both subscribers and operators. For example, consider a premium-tier video service that enforces the maximum quality of service through the operator’s network and guarantees the best possible video viewing experience at all times. Many mobile subscribers would be more than willing to pay a monthly premium for a service like this.
The bottom line is that when you add cell awareness to your traffic management toolkit, you get an accurate picture of th
e who, what, and where of da
ta traffic as well as the ability to manage it dynamically and efficiently to the benefit of all.
Jonathon Gordon is director of marketing at Allot Communications.