Heard on the net recently: AT&T might label the iPhone 4S as a 4G phone? Really? The purists cringe.
I find this amusing in a technology vs. marketing sort of way. AT&T is competing hard with Verizon on 4G coverage. Verizon is winning in terms of deployments and AT&T’s Mobility Leadership admitted it. AT&T claims to have faster speeds in 4G tests vs. Verizon; this is very regionalized and subject to many network conditions – channel bandwidth, encoding schemes and antenna usage.
The question is what does 4G actually mean and when did 3G end and 4G begin? It’s all a little gray… and was made worse when the ITU reversed a decision in December 2010 and stated that HSPA+ was a 4G technology even though it preceded LTE by years.
The iPhone 4S does have an HSPA+ enabled radio on the AT&T network. HSPA+ was defined in the 3GPP Rev 7 spec in the 2006-2007 timeframe. LTE was defined in the 3GPP Rev 8 spec in the 2008-2009 time frame. Many believed that the Rev 8 spec was where the 3G and 4G boundary was. That is, until the ITU changed its mind.
Some in the technical community suspect that the iPhone 4S lacks a few current technical enhancements to make it real 4G (e.g. 64QAM encoding in both the uplink and downlink). We will soon find out as the phones are shipping now and no doubt detailed test results will appear on the net.
The bottom line: this is way too complex for consumers to understand.
As for coverage maps, see for yourself:
AT&T HSPA + map
Verizon LTE map
This is one reason why AT&T is pursuing T-Mobile – to expand their HSPA+ network.
Today’s carrier networks are evolving and the features required for the highest throughput are not available everywhere creating a situation where marketing hype will thrive – let the carrier 4G battles continue.
A 4G label on the iPhone 4S is a stretch in that it’s not real 4G based on what networking purists believe. However, given the ITU’s reversed decision in Dec 2010, it is sort of true…and clearly gray.
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Geek Speak:
AT&T 5MHz/channel HSPA+ and Verizon’s 10MHz/channel LTE can be roughly equivalent throughput-wise IF (the proverbial big “IF”) favorable radio conditions exist and IF AT&T uses certain networking techniques (e.g. channel doubling, 64QAM and 2×2 MIMO). One wonders what 64QAM and 2x MIMO are. 64QAM = 64-bit quadrature amplitude modulation – basically how analog and digital signals are converted to symbols for transmission. MIMO is Multiple input, multiple output. Contrasted with MISO – multiple input single output, not the soup! and SIMO – single input multiple output. 2×2 MIMO is 2 transmitting antennas and 2 receiving antennas effectively doubling the throughput on a point-to-point link. You may recall Apple talking about using two antennas in the iPhone 4S. Is this MIMO on the device side? We will soon find out.
Tags: AT&T, Dan Zeck, iPhone 4S, Mobile Mastery
