by Ian Littman
Sprint 4G Rollout Updates
Friday, September 14, 2012 - 9:35 AM MDT

In the past, Apple’s iPhone wasn’t quite the ideal Sprint phone from a network perspective; it lacked 4G of any sort and didn’t include support for Sprint’s nascent SMR-800 1x CDMA network (in place of Nextel iDEN). The situation could be worse (for example, CricKet iPhones can’t get native service in many of the company’s newer, AWS-only markets), but as a flagship phone it was odd to see the iPhone lacking one core piece of Network Vision support that every other Sprint phone released in the past year has had.

That issue has now been solved...sort of. I’m Ian Littman, standing in for AJ (aka WiWavelength) with an analysis of the non-AT&T edition (A1429) of the iPhone. I’ll focus on the pieces that Sprint subscribers will use, as the phone supports a cornucopia of bands and technologies (quad-band GSM/EDGE, quad-band HSPA+ including dual-carrier, EvDO Rev. B with up to 3 carriers in the cellular band) in addition to CDMA 1x, EvDO and LTE (in 2100MHz and 1800MHz, which Sprint won’t use).

So, without further ado, the rundown:

Quote

• CDMA 1xRTT, 1xAdvanced, EvDO rev. A in band classes 0 (Cellular 850), 1 (PCS 1900) and 10 (SMR 800)
• LTE in a variety of bands, including the US-compatible...
  • Band 5 - Cellular 850 (1.4, 3, 5, 10MHz)
  • Band 13 - Verizon upper-C 700MHz (5, 10MHz)
  • Band 25 - PCS 1900, including G Block (1.4, 3, 5, 10, 15, 20MHz)

  [*]No VoLTE or SMR LTE support (as expected)

  [*]Three antennas: two for cellular, one for WiFi/Bluetooth (so WiFi is still 1x1 SISO)

  • 2.4GHz WiFi and Bluetooth can’t co-transmit; 5GHz WiFi and Bluetooth can
  • Wireless tethering only available in 2.4GHz
  • Only one cellular antenna can be used to transmit at a time
  • Only one cellular technology can be used to transmit at a time (so no SVLTE, and very likely no SVDO)
  • Either cellular antenna can be used to transmit, but the antenna-switching process includes a period where no transmission is made
  • EIRP of 22.00 dBm on CDMA in SMR, 22.81 in Cellular, 28.40 in PCS for the primary (bottom) antenna, 17.00/18.57/24.61 for the secondary (top) antenna
  • EIRP of 22.12/22.57/27.36 dBm in 700/Cellular/PCS for LTE on the lower antenna, 21.54/17.32/23.96 on the upper antenna
  • Antenna gain of -1.73/-0.86/1.04 dBi for the lower antenna on SMR, Cellular and PCS, respectively, and -5.47/-4.33/-2.9 for the upper antenna*

* 16QAM modulation, 5MHz channels on Cellular/PCS, 10MHz channels on 700MHz; QPSK adds another 1-1.5 dB of output power, as does switching to 5MHz channels on 700MHz

On the surface it looks like the iPhone is a very capable device; it can realistically hit 100 Mbps on LTE, using both its antennas to receive (but not send) the signal on a 20MHz channel (which a number of Sprint phones don’t support, my Galaxy SIII included). It supports a ton of bands (my bet is that even the “GSM version” of the A1429 has CDMA built in, but it is not certified/disabled in non-CDMA countries) and technologies. However the good news ends there.

For example, several Sprint phones now have SVDO and/or SVLTE support; you can make a call on 1x while maintaining a data connection. The Sprint/Verizon versions of the iPhone, to our knowledge, can’t do that. The best it can do is VoIP over LTE or EvDO...garden-variety VoIP, not the more robust VoLTE variety. Being able to transmit LTE on only one antenna isn’t terribly surprising...most current phones are 1x2 MISO (Multiple In Single Out), however Apple’s attention is obviously directed at carriers with HSPA networks when it comes to delivering a high-quality wireless experience. Another example of this is Apple’s HD Voice ability; Sprint will be the first US carrier to support the technology, but not on the iPhone, which can only use HD Voice over WCDMA.

Apple’s ability to pack a ton of bands into a single, super-slim phone is definitely a technological marvel, particularly in conjunction with a wide-channel LTE network (since the iPhone’s WiFi is SISO, it may be able to pull down data more quickly on LTE than on 802.11n, given ideal conditions on both). However a tailor-made Sprint phone it most definitely is not, though the inclusion of SMR CDMA softens the blow a bit.

As an aside, the AT&T edition of the iPhone supports LTE in the PCS (without G), AWS and Cellular bands, in addition to AT&T’s current 700MHz lower-B/lower-C network (band classes 2, 4, 5 and 7, respectively). So the AT&T edition of the phone is actually a better fit for providers like CricKet, MetroPCS and US Cellular...if not for the glaring omission of those carriers’ 3G network technologies (and VoLTE).