3G capacity shrinks as users migrate from GSM networks

In his wireless blog, Mark Heath, of Unwired Insight, explains how available 3G capacity per device is falling.

As mobile users increasingly migrate from 2/2.5G to 3G networks, the available 3G network capacity is being shared among a greater number of users. By 2014, a typical incumbent mobile network operator would see its 3G capacity per device shrink to a quarter of its 2008 level if it made no technology upgrades. Just to stand still and maintain current levels of network capacity per device, mobile network operators would have to upgrade from HSPA to HSPA+ and/orLTE.

Following the launch of 3G services by operators, the total available 3G network capacity had to be shared among a relatively small number of users, resulting in a relatively large capacity per user. This is why 3G operators were initially unconcerned about the take-up of mobile broadband services, even though they can consume large amounts of network capacity (in excess of 1GB per user).

However, the continued migration of customers from 2/2.5G to 3G services, together with the ongoing increase in overall cellular device penetration, will cause network capacity per 3G device to shrink dramatically for a given technology.

To demonstrate this effect, let’s take a typical incumbent 3G operator in Western Europe with 20 million customers (split between 2G and 3G networks), 15 000 3G base station sectors and 2 x 10MHz of 3G spectrum. With a relatively small number of 3G devices initially, this operator’s network could support an average traffic level of 352MB per month per device if it used HSPA technology in 2008. However, as users migrate from 2/2.5G to 3G services, this figure falls below 80MB per month per device by 2014 (less than a quarter of its level in 2008).

What makes this fall in capacity per device even more problematic for mobile operators is that the usage per device is increasing strongly, and will continue to do so as smartphones and broadband dongles become a larger proportion of the 3G devices in use.