Mobile data traffic
15 January 2011 |
Mobile backhaul is the means of delivering mobile traffic from the cell tower to the core network and back again.
Traditionally, this traffic consisted of voice and SMS data; but since 2007, with an explosion in mobile broadband traffic, mobile backhaul has come to the forefront and is now regarded as one of the most critical elements in a mobile network.
Why is mobile backhaul now critical?
Voice and SMS data traffic is predictable and consistent, meaning that until 2007 backhaul networks didn’t require high-speed connection with high throughput levels. Most operators used fixed-line bonded copper or point-to-point microwave radios to backhaul their networks. However, mobile broadband data is “bursty”, occurring at any point, anytime and anywhere, making it unpredictable and difficult to manage.
When operators in the UK began rolling out enhanced 3G protocol high-speed packet access (HSPA), which has a peak data rate of 14Mbps downlink and 5.8Mbps on the uplink, copper wires were no longer a valid and practical backhaul means for the high-speed data that gives HSPA its name. Operators needed an alternative and needed to find one fast.
What caused the explosion in mobile broadband traffic?
A number of disruptive events have contributed significantly to the explosion in mobile data. First was the introduction of the 3G dongle, allowing consumers to access the internet on their laptop without having to connect via an access point or router. Initial uptake was slow, but after being on sale for a year, unit sales in September 2008 in the UK hit over 18,000 a week. The advent of the 3G iPhone brought a new consumer demand for the internet, making access available whenever, wherever and in the palm of our hand. By the end of 2008, Apple had sold 6.89 million handsets worldwide, and manufacturers started designing and developing their own “copy-cat” devices.
The initial tidal wave of data over mobile networks had arrived and the effects were realised almost as quickly. Bottlenecks in the network meant that advertised HSPA speeds were never a reality. Voice and SMS data was also caught up in the backlog of mobile data, leading to dropped calls coupled with poor connectivity and slow data rates. The real tsunami is yet to come however, with the latest connected device being the tablet PC. Again, Apple justified the hype with the launch of the iPad and there are now over 20 different tablet PCs on the market.
Tablet PCs are ideal platforms for mobile web browsing, adding yet another considerable data load to the mobile networks. We now have a much wider base of data-equipped devices with the potential to consume much more data, yet mobile network operators have done little in the way of major network upgrades. The result is that all these devices are trying to use the same pipe they were 12 months ago. The pipe has finite capacity and because of the way radio access networks are configured, they will allocate as much capacity as is available to the devices requesting it - 10 simultaneous users on a single cell site may use the same capacity as 100 simultaneous users. The service for the 100 will be degraded relative to the 10, because it is physically impossible to squeeze more through the fixed capacity pipe.
How are mobile traffic patterns shifting?
We’re starting to witness a shift in mobile traffic patterns. Traditionally, the majority of 3G data traffic takes place in urban areas where network infrastructure is more prominent. However, the tablet is a valuable addition to the home, ideal for quick tasks, email or social networking in front of the TV. With over 1.5 million UK homes using mobile broadband as their primary means of internet access, tablet PC use in the home environment will squeeze the pipes even further.
This shift and the escalation of mobile data traffic in residential urban and suburban areas warrants the need to increase backhaul capacity. This is not without its own challenges. Fibre is considered an ideal solution for backhaul with its high capacity and efficiency; however, rolling out the amount of fibre-to-the-doorstep needed is expensive, and disruptive as roads are excavated.
Microwave technology is another solution to extend network capacity in these areas, but few residents would welcome a massive proliferation of point-to-point radio installations.
How do we stop the networks from failing?
Backhaul network upgrades are inevitable to tackle the data influx. Today’s legacy backhaul networks are voice-dominated, circuit-switched environments and almost universally based on point-to-point architecture, which has worked well for traffic that is consistent. But traffic in the backhaul network is “bursty” and uncorrelated. We need to look at the long-term evolution (LTE) of the network.
LTE technology in the radio access network (RAN) is particularly efficient; it handles and allocates available data capacity in what is essentially a “one-to-many” architecture. The only sensible way to address the issue in the backhaul network is with the same point-to-multipoint architecture. Backhaul capacity can be shared among cell sites according to demand in the same way that RAN capacity is shared amongst end users. The alternative is to provision all point-to-point connections for the peak load; nothing could be more inefficient. Furthermore, the one-to-many nature of point-to-multipoint microwave reduces the number of radios required to create networks by up to half, meaning that backhaul networks can be deployed in hours rather than days, and at half the cost of the alternatives.
Point-to-multipoint microwave backhaul technologies are available and have been enthusiastically adopted in developing markets. Emerging technologies also promise to deliver the same approach to fibre networks. The provision of mobile data access is a tough issue for operators but it’s not insurmountable. When properly addressed with appropriate and efficient technologies, it will allow growth and deliver the necessary margin to mobile operators.
Contact: Cambridge Broadband Networks
For further information, contact Lance Hiley, VP of market strategy at Cambridge
Broadband Networks at: firstname.lastname@example.org
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