5G Wireless: Don't Get Your Hopes Up

I'm giving a talk this evening for the Boston Chapter of the IEEE Communications Society on the subject of 4G and Beyond. My intent here is an analyst's-eye-view of 3G, why we need to move to 4G (or do we?), and what 5G might look like - if it materializes at all. In doing the research for this talk, I came to a number of interesting conclusions, not the least of which is that 5G might not be necessary or even possible.

3G is well-established, even if buildouts are far from complete even here in the US. The idea is to augment good old TDM voice with broadband data. The carriers recognized a long time ago that data would need to be the engine of growth once the voice market saturated, and we're certainly now there - the CTIA estimates that we're above 80% penetration - of the entire population of the US - in terms of cellular subscribers today. And demand for data services continues to build, requiring both rationing via higher prices and service caps as well as the need for massive new spending on backhaul capacity in order to really offer broadband data.

4G brings voice and data together under the IP umbrella, essentially extending the contemporary thinking around wireline to wireless - make it all-IP. And it now appears that LTE is going to be the 4G technology of choice, distantly followed by mobile WiMAX. And while I think the deployment of LTE will in fact be required not just to augment capacity and throughput, but also to smooth operations overall and in the bargain improve spectral efficiency, future upgrades to HSPA (really a 3.5G technology) may moderate demand for LTE, or eliminate it altogether in some markets. There are plans to extend HSPA to 40+ Mbps on the downlink, and possibly much more than that.

But there's regardless so much momentum behind LTE that it really can't lose, and we're potentially looking at up to 300 Mbps here. So why even talk about 5G? Loosely defined (and that's all the definition we can have at present), 5G is throughput of 100 Mbps or more, all the way up to 1 Gbps. Yes, we're talking about wireless WANs here, not Wi-Fi. Have a look at LTE Advanced and 802.16m for an idea of the technology now under development to address this opportunity. It's real.

But it's the economics of 5G, not any technological risk, that may hold it back. What, more base stations? Huge new chunks of expensive spectrum required? More handsets, buildout expense, support costs, and on and on? I think many carriers may just say no, thanks, or at the least postpone any plans for testing, let alone deployment of 5G, to 2015 or even later - much later. In short, we've got or will get the technology, but the money likely won't be there, and 3.5G and 4G deployments (with technical upgrades) will be able to carry us for some time. It's all in the hands of the carriers - and they're in it for the money, not to advance the state of the art.

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