The promise of "internet everywhere" is rapidly becoming reality with the proliferation of cellular broadband networks. Spurred by the popularity of smartphones and web access on the go, both cellular networks and smartphones have evolved symbiotically — each pushing the other ahead.
Today, all the major cellular carriers feature widespread 3G deployment and are talking a big game about 4G, which is poised to permeate the U.S. throughout 2011. Meanwhile, although only 21 percent of Americans owned smartphones in late 2009, that number jumped to over 35 percent in late 2010 and is expected to top 50 percent by the end of 2011. With both mobile access and smartphone use increasing rapidly, the market for mobile apps for both work and leisure is likewise ballooning. There are now more than 400,000 mobile apps available. Clearly, when it comes to the direction of software development, mobile apps are where it's at.
But there are potential challenges to consider. Cellular broadband networks face more constraints than operators of cable and fiber networks do. Today, most smartphone users access 3G networks. In the real world, many users see speeds ranging from 500kbit/s to 1Mbit/s on 3G networks, although on paper the technology is capable of higher speeds. A major bottleneck with cellular networks is that users within a certain area must share a single broadcast tower, and each tower has a finite amount of bandwidth available to it. 3G networks in particularly can be seriously hampered by this problem, as was notoriously demonstrated when the iPhone launched and brought AT&T's network to a crawl in many larger cities.
The term "4G" does not actually represent a single technology. In U.S., several 4G-branded networks are being launched by different carriers, using several technologies, including WiMax, LTE and HSPA+. There is some controversy over whether any or all of these actually qualify to be called 4G, but in practice the carriers are doing so anyway. Semantics aside, real-world tests suggest that 4G users will typically see speeds about double their 3G counterparts, although once again the theoretical speeds marketed for each 4G technology are substantially higher than users will experience.
Carriers are also implementing more aggressive bandwidth caps, perhaps in an attempt to limit bottleneck problems. Ironically, users of 4G networks face limits on how much data they can transmit, but because of the increased network speed, they can and often will hit these limits even more quickly than 3G users.
What all of this means for mobile app developers is that your software faces many unknowns: you don't really know what generation of cellular broadband network your user is on, nor do you know what bandwidth caps may be in place (because these vary among carriers and service plans).
In general then, mobile development should conform to three, safe-bet assumptions. The first is that speeds will be erratic. Whether your user is on a 3G or 4G network, actual speeds can vary considerably based on signal strength and tower load, so you can't rely on any predictable performance minimum.
In addition, latency (delay) will be high. On an average, users typically see about 100ms and higher latency on cellular networks; we may see some 4G networks get this down to about 50ms in best case scenarios. Compared to latencies as low as 10 to 30ms on many terrestrial broadband networks, 4G response times may be somewhat slow. Applications that rely on instant response, such as voice over IP (VoIP), will perform more erratically on 3G/4G networks than on terrestrial networks.
Finally, bandwidth will be metered. Because of aggressive carrier caps, mobile app users will increasingly be concerned with data consumption. Mobile apps will need to become more efficient in transmitting data, and those that are deemed "data hogs" may not last for long in the commercial marketplace.
For more information, see:
Is Mobile Security Worth Worrying About?
Employee Web Usage Policies: Pros and Cons
Make "Bring Your Own Technology" Policies Work for Your Enterprise
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