Can LTE Really Do It All?

LTE is most certainly the most robust cellular technology developed to date. But is it the One Radio to Rule Them All? It could indeed be - but it won't.

If radio were invented today, it would most certainly and fundamentally be broadband. Actually, when radio was invented, it was indeed broadband in the sense of consuming a lot of spectrum; Marconi's first spark-gap radios were practically ultra-wideband! But they were pretty narrowband WRT information content, with throughput basically limited to the speed at which a Morse-code key could be toggled. And, of course, may apps, like voice, are fundamentally narrowband (if time-bounded) in nature. But narrowband apps can be easily mapped onto broadband channels, and the reverse certainly not being true, the strategy of moving these apps to broadband is obvious - and being applied even in the case of that most established of wireless apps, push-to-talk (PTT or P2T).

I spent some time wandering through the exhibit hall at the recent IWCE (International Wireless Communications Expo) conference in Las Vegas. IWCE positions itself as a general-purpose kind of show, but the focus is clearly on vertical applications related to PTT technologies, like public safety and utilities. There's actually been a bit of excitement in this otherwise staid area as a push to digitalization has been underway for some time, with the primary goals of improved spectrum utilization (a key benefit of digital radio in the first place) and to a lesser degree improved access to data.

The most important activity here is known as Project25, also known at P25 or APCO-25. P25 is of course digital, and is thus way more spectrally efficient than analog PTT radios. It specifies channels as small as a very-efficient-indeed 6.25 KHz., and also includes encryption. Most importantly, P25 brings a degree of interoperability that's been such an obvious need for years, and especially after 9/11. First responders that can't communicate with other public-safety entities can't be a good thing.

But here's the problem - if LTE can handle PTT, and it can (and with gateways now appearing to integrate P25 as well as older PTT systems and technologies), then why do Project25 at all? Why not just move entirely to LTE? Indeed, I asked (and was asked) this question several times during the IWCE show. If LTE had been just a little faster through its development process, it might have indeed become everyone's PTT solution. And you long-suffering Nextel users also have a dog in this fight (harmless pun intended; please, no Michael-Vick-esque hate mail). Nextel as we know it has been doomed for years, as Sprint continues to struggle with both iDEN and QChat as well as its own business issues. But should this service be moving to LTE (of course it won't in Sprint's case, as they're a WiMAX shop via ClearWire) regardless? Why not?

Alas, history often works against us in wireless. Existing frequency allocations, spectrum auctions, huge installed bases, the very diversity of an industry where some key players just don't talk to one another, and individual corporate objectives usually work against one another in the production of optimal (from the perspective of us mere users, anyway) results. Here we have yet another missed opportunity to optimize spectrum allocations (as I've previously written, do we really need to reserve bandwidth for certain users or applications? No, we don't.) and provide broadband to everyone in the event an application requires it now - or in the future. So I'm afraid that that the answer to my question above is going to be no - and, again, yet another lost opportunity.

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