11 ways around using more spectrum for mobile data

Demand for mobile data capacity is growing faster than new spectrum can be cleared, but there are alternatives

8. Compression

No matter what frequencies are used to carry mobile data, less traffic means less spectrum is needed. Data compression is a time-honored way of cutting files down, but it has its limits as a solution to the wireless crunch, according to Rajat Roy, a senior product line manager at Broadcom. To start with, the biggest files, such as video, audio and images, are already compressed using standard protocols such as JPEG and MPEG. For other types of files, the industry is still trying to settle on a common standard so mobile devices will have the software to decompress what's been compressed in the network.

However, Broadcom has targeted one type of traffic that doesn't make for huge files but is often inefficient. The company builds technology into its wireless base-station chips that can compress the header fields of VOIP (voice over Internet Protocol) packets. Though voice doesn't take up much bandwidth, the packet headers containing routing and other information are sometimes twice the size of the payload itself, Roy said. Compressing the headers reduces the load on the network.

9. Caching

There are at least two ways in which caching could help reduce the need for spectrum. One is time-shifting traffic to reduce peak demand. The growing amount of storage capacity on devices and in removable flash cards could allow users to download large files such as video automatically during off hours, said Tolaga Research analyst Phil Marshall. Users who signed up to have that content sent could then watch it later on the device. Security and digital rights management are possible barriers to adopting this technique, Marshall said.

Broadcom has another caching idea: The company equips its cellular base station processors to identify and cache multimedia content while sending it out to client devices. The idea is to keep filling the "time slots" on a wireless pipe that the network allocates for the file transfer. Letting those slots go unfilled wastes network capacity. Broadcom's chips can store enough packets of a file or a multimedia stream in memory so that the base station can pack as much data as possible into every time slot devoted to that application, Roy said.

10. Reducing signaling traffic

In some cases, it isn't mobile video or big email attachments that are consuming an operator's spectrum, but small signals sent between devices and networks. With busy applications such as push email, social networking and even Web browsers, these small signals can add up.

"We've seen cases where carriers had lots of data capacity ... available in their network and congestion being defined by signaling capacity limits," said Peter Carson, a senior director of marketing at Qualcomm. He expects the problem to get worse.

In its mobile modem chips, Qualcomm is implementing several technologies that reduce signaling. One is a more efficient way for applications to request network resources and switch between communication modes. Another helps the modem to combine network requests and data traffic from a device's application processor in batches. These techniques also tend to slash power consumption, extending battery life. They should be available soon in devices equipped with Qualcomm modems, Carson said.

11. Pricing and data caps

Finally, technical and regulatory solutions are only part of the picture. The most powerful tool to prevent spectrum becoming overloaded may be regulating mobile traffic through service plans.

Most carriers are well along in phasing out unlimited data plans, if they ever had them. Now that monthly usage caps are in place, the service providers can modify them as needed to discourage subscribers from using too much network capacity. They can also fine-tune subscriber behavior by encouraging time-shifting or charging more for plans where the subscriber's packets get priority over other traffic.

"If I have a flat-rate plan on my iPad, and I can jump onto LTE whenever I like, that's what I'll do. But if it's a plan that doesn't allow me to do that, and I'll pay a premium to use that LTE network, chances are, I'm going to jump on to Wi-Fi," Marshall of Tolaga Research said.

If one carrier can make its spectrum support a plan that satisfies consumers, others will use whatever tools they need to try to match it, Marshall said. "It's market competition that will define how many cell sites, how much spectrum, and what techniques are used to deliver the service, as opposed to pure demand," Marshall said.

Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is stephen_lawson@idg.com

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