Friday, May 02, 2008

Is LTE too LATE?

Mobile wireless standards seem to be a hodge podge of alphabet soup technologies. There's 1xRTT, EVDO Revs 0, A, B & C, GPRS, UMTS, HSDPA, EDGE, and LTE. Why so many? For the same reason that there was Pentium I, II, III and IV, just to mention a very few of the CPUs that came and went in the last quarter century. While PC designs have achieved a certain level of maturity, wireless broadband is still scrambling up the learning curve. The latest that has mobile content providers drooling is called LTE. But is LTE really the next big thing or is it too LITE or too LATE?

The acronym LTE stands for Long Term Evolution. But evolution of what? GSM data networks, that's what. Even beyond GSM networks. It's intended to be worldwide standard for mobile communications created by the the 3rd Generation Partnership Project (3GPP), a collaborative project among telecommunications organizations. In the long run, or should we say long term, LTE will supersede a potpourri of other standards including GPRS, EDGE, HSDPA, HSUPA & HSPA+. Some of these are familiar. Others you may have never heard of. If LTE evolves fast enough to kill off these lower species, you may never get familiar with them.

Perhaps the most familiar of this group is EDGE or Enhanced Data rates for GSM Evolution. This is the wireless broadband standard implemented in the Apple iPhone. AT&T is the largest GSM carrier in the United States. It's a well established technology, but just barely qualifies as broadband. Download speeds are up to 237 Kbps, typically half that. This is why iPhone users are screaming for 3G.

HSDPA or High Speed Downlink Packet Access would be the next upgrade. This standard picks up where EDGE leaves off and ramps broadband speeds up to a theoretical maximum of 14.4 Mbps. Quite an increase. In practical use, the download speed you'd experience is likely to be half that or less. Still, Mbps instead of Kbps. Who could ask for more?

At some point, you'll be the one asking for more. We're use to stifled bandwidth and especially stifled mobile bandwidth. That's why we've settled for "mobile" browsers, text messaging, and email. The nice thing about the iPhone is that if you run out of patience waiting for pages to load, you can always get a coffee or some lunch and use the restaurant's free WiFi to get some decent bandwidth. But then it's time to hit the road again and there goes your Internet experience.

Deploying HSDPA and its upgrades will support today's applications. You'll be able to get mobile performance that feels similar to WiFi hotspots. But carriers will still be playing catch-up as customers become enamored with new high bandwidth applications, such as HDTV, and wonder why they still feel stifled.

Carriers such as AT&T with plans to deploy LTE networks hope to get ahead of the curve. That's what the "long" in long term evolution implies. Imagine having 300 Mbps download speeds at your command. That's along with 75 Mbps upload. True, that's likely to be the performance you'd get right under the tower with nobody else on the channel and no breezes blowing. But still, it's 300 Mbps.

Interestingly, the real powerhouse wireless technology being touted for mobile applications has a maximum download speed of about the same 75 Mbps that LTE offers on the upload channel. That's WiMAX. WiMAX is on its way and we might see Sprint's network in operation this year. That is, if the money holds out.

LTE offers another intriguing characteristic. It has low delay times or latency. How low? How about 10 msec? You're lucky to get under 100 msec on wireline Internet services. The high speed link coupled with low latency characteristics makes LTE a good candidate for lots of new applications, especially real time applications. That suggests not only VoIP telephony but high resolution video conferencing as well. Also real time gaming, television and video on demand, medical imaging and engineering file transfers.

I think it's clear that LTE is certainly not LITE when it comes to performance. It's not too LATE either. WiMAX is taking its good old time rolling out and EVDO Rev C, which might also be a competitor, is also nowhere to be seen. That leaves a nice window of opportunity for LTE just as higher bandwidths are starting to become necessary for more demanding applications.

Follow Telexplainer on Twitter