Reader Forum: High traffic networks need a congestion solution, not a congestion charge

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Wireless carriers are introducing tiered mobile data pricing as a way to ease network congestion. Although not popular with consumers, this approach is seen as a necessary response to the exploding demand for mobile data services. However, encouraging subscribers to use less data is not the only answer. Femtocells provide one attractive alternative for both operators and consumers.
A surge in the use of iPhones and other smartphones has led to congestion and customer dissatisfaction on a number of city and urban networks. When city planners look at road traffic congestion issues, they often turn to a “pay-per-use” congestion charge to discourage motorists from bringing their vehicle into over-crowded areas. The same principles can be applied to mobile data, with today’s flat-rate plans and fair usage policies likely to be superseded by strict overage charges and usage based pricing schemes.
AT&T’s head of consumer services, Ralph de la Vega, provoked a media backlash last December when he talked about giving high-bandwidth mobile data subscribers “incentives to reduce or modify their usage.” Despite the unpopularity of the concept with consumers, AT&T has followed through and announced that it will stop selling unlimited mobile data plans to new smartphone customers and instead will offer a choice of 200 megabyte or 2 gigabyte capped plans. Vodafone made similar announcements in the U.K. recently, and is already offering subscribers in Spain the chance to have their traffic prioritized when the network is congested – for an extra €49 per month.
But premium pricing isn’t the only way for operators to control congestion. Many are considering femtocells as an alternative which can offer premium services to consumers while at the same time providing a congestion solution that works for everyone.
For example, AT&T is in the process of rolling out its femtocell (the 3G MicroCell) across the United States, while Verizon and Sprint are both planning to upgrade their current 2G femtocells to handle 3G data as well as voice services.
Wider deployment of 3G femtocells will not only improve cellphone coverage in homes, it will also help ease congestion problems faced by many operators on dense city centre 3G networks.
Femtocells help solve radio network performance issues caused by interference from a dense population of smartphones. A cellphone communicating with a nearby femtocell transmits at a much lower power than if it were signaling to a cell tower, thereby reducing the uplink interference it creates. Reducing interference in this way improves service quality and data speeds – not only for the femtocell user, but also for all other cellphone users in the area. According to Gordon Mansfield, AT&T’s Executive Director of RAN Delivery, “The more femtocells you deploy, the more uplink interference is reduced.”
Furthermore, indoor users consume more than their fair share of the cell’s resources because the radio waves must pass through signal-absorbing walls to reach them. If these users are served via femtocells instead, outdoor users also benefit from improved quality of service – in fact, the capacity of the macro network improves out of all proportion to the number of users who have been removed from the cell. Considering that the majority of mobile data is consumed indoors, even a relatively sparse population of femtocells can make a difference.
Congestion issues are compounded by smartphone applications which cause a heavy signaling load on the Radio Network Controllers that manage radio resources on the mobile network. The problem is that “always-on” applications are constantly making brief connections to the network to retrieve updates (e-mail, weather, stock quotes, etc). As a result, the RNCs become a bottleneck and slow down network performance for all users.
With a home femtocell, the RNC is incorporated within the unit itself, and the traffic is routed away from the bottleneck. This means that not only do femtocell customers get a reliable, fast 3G service in their home, but the load on the network RNCs is reduced, improving service for other cellphone users.
Public reaction to femtocells in the United States has been enthusiastic, but some have criticized the carriers for asking their customers to pay for the devices. The argument goes that carriers are effectively asking their customers to subsidize network improvements by paying twice for the same service – especially since femtocells backhaul traffic over the customer’s broadband Internet connection, thereby reducing the cost to the wireless carrier of delivering its services.However, femtocells benefit their owners (and their friends and family) more than other network users. Because the femtocell is a personal cell, not shared with other network users, it delivers premium quality voice and faster data rates. Back to the traffic analogy, expecting a free femtocell is rather like expecting the city planners to provide extra lanes on the highway for personal use. While it’s reasonable to expect the planners to invest in widening the highway to cope with extra traffic demand (and indeed the carriers do continue to invest in improving their 3G macro networks), a personal lane is not something you’d expect to get for free, even if it does help ease congestion in the shared lanes.
Moreover, many operators (including AT&T, Vodafone in the U.K. and SoftBank Mobile in Japan) are offering incentives for subscribers to adopt femtocells, including free femtocells as part of service bundles.
Finally, in many cases there is no real alternative to femtocells for improving service quality inside homes and offices. The other option is for carriers to invest in more cell towers and radio masts, ever closer to people’s homes. Not only would that be more expensive in the long run for the consumers, it is also environmentally unworkable.
Dr. Andy Tiller is VP Marketing at ip.access and a board member of the Femto Forum. ip.access provides the core femtocell technology to Cisco for AT&T’s 3G MicroCell, currently being launched city by city across the USA.