Just about every major mobile operator is moving towards LTE, but they aren’t walking in lockstep. Even the LTE pioneers, such as TeliaSonera, Verizon Wireless and NTT DOCOMO, are each marching to a slightly different tune.

One of the key differences in the early LTE deployments will be the spectrum bands they use. Whereas TeliaSonera has launched networks in Stockholm and Oslo using 20MHz radio channels in the 2.6GHz band, Verizon is planning to use 10MHz channels in the 700MHz band. NTT DOCOMO is deploying LTE at 2GHz initially, but later plans to also use the 1.5GHz spectrum band.

That means LTE dongle and handset manufacturers will either have to make different products for different markets or will have to go to the additional expense and hassle of producing devices that can support all these bands. More importantly, the choice of spectrum bands, which have different propagation characteristics, also has implications for an operator’s LTE strategy, which will influence the kinds of devices, services and apps they want to deploy.

The 700MHz band, for example, is ideal for providing coverage over a broad geographic area using relatively few base stations, but is less suitable for providing lots of capacity in a congested hotspot. Radio waves travel much shorter distances at 2.6GHz, so this band doesn’t lend itself to rural or suburban coverage, but is well-placed to handle the heavy demand in city centers, airports or rail stations.

How wide is your channel?

Another complicating factor is the actual size of the channels each of the operators has to use. To provide mobile broadband services that are significantly quicker than those enabled by HSPA+ networks, LTE operators will probably need 20MHz channels.

Verizon’s narrower radio channels and lower frequency spectrum explains why the U.S. operator talks about average throughput speeds of 5-12Mbps in the downlink and 2-5Mbps in the uplink for its forthcoming LTE network, whereas TeliaSonera is positioning its LTE network as providing throughput speeds of up to 100Mbps.

In an ideal world, all LTE operators would have 20MHz channels in both the 700MHz-800MHz and 2.6GHz bands, which look like they will be the most commonly-used bands for LTE. But this is far from an ideal world – some LTE operators will have to make do with smaller channels in bands between 1GHz and 2GHz. Moreover, spectrum can come with regulatory strings attached. Some operators, notably China Mobile, will have to deploy LTE in TDD (time division duplex) spectrum rather than the more commonly use FDD (frequency division duplex) spectrum.

Spectrum realpolitik means the LTE community will have to be a broad church tolerant of many different approaches to deploying this advanced mobile broadband technology. This diversity will obviously make it tougher for device makers targeting the fledgling LTE market to get the economies of scale they need.

But LTE diversity also has more subtle implications for application and service developers. Verizon and other operators with low-frequency spectrum are likely to place much greater emphasis on machine-to-machine applications, such as remote meter reading and environmental sensors, than operators with high-frequency spectrum, which are likely to focus initially on providing high bandwidth services to high-spending customers, such as business travelers. The channel-width available to LTE operators is also going to be a major factor in determining the success of the most demanding applications, such as high-definition video-on-demand or video conferencing.

When it comes to LTE, not all networks will be created equal.