There was no way Apple could release the LTE iPhone 5 because the currently shipping chips won't fit on the iPhone PCB, reports AnandTech.
The iPhone 4 PCB is already incredibly small, not leaving any room for an extra chip to enable LTE without shrinking the size of the battery (or increasing the thickness of the phone to accomodate both a larger PCB and a big battery). Today, Qualcomm is a leading provider of LTE baseband silicon and unfortunately they don't ship any baseband hardware that supports both LTE and voice (over 1x/WCDMA) without extra silicon. In order to support both you need to be using something Qualcomm calls SoC Fusion. By leveraging a Qualcomm Snapdragon SoC in combination with Qualcomm's MDM9600 LTE modem you can deliver both voice and LTE data. Otherwise the MDM9600 is only good for data, which is admittedly useful in things like USB modems or MiFis. Apple obviously doesn't use Qualcomm Snapdragon SoCs so enabling LTE on the iPhone isn't possible using Qualcomm baseband unless you make the phone's PCB larger (which Apple obviously wasn't going to do).
Anand notes that while the MDM9600 is a 45nm process, the MDM9615 which is expected in 2012 is built on a 28nm process. This chip is 10x10nm, is voice enabled, and would likely fit. Qualcomm's roadmap shows the MDM9615 arriving in Q2 2012.
Also, there have reportedly been problems at TSMC and Global Foundries in making the switch from 45nm to 28nm and Anand suggests these setbacks affected the smartphone's release schedule.
"I suspect that an aggressive 28nm roadmap that didn't pan out probably caught a lot of SoC and smartphone vendors in a position where they couldn't ship what they wanted to in 2011."
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The iPhone 4 PCB is already incredibly small, not leaving any room for an extra chip to enable LTE without shrinking the size of the battery (or increasing the thickness of the phone to accomodate both a larger PCB and a big battery). Today, Qualcomm is a leading provider of LTE baseband silicon and unfortunately they don't ship any baseband hardware that supports both LTE and voice (over 1x/WCDMA) without extra silicon. In order to support both you need to be using something Qualcomm calls SoC Fusion. By leveraging a Qualcomm Snapdragon SoC in combination with Qualcomm's MDM9600 LTE modem you can deliver both voice and LTE data. Otherwise the MDM9600 is only good for data, which is admittedly useful in things like USB modems or MiFis. Apple obviously doesn't use Qualcomm Snapdragon SoCs so enabling LTE on the iPhone isn't possible using Qualcomm baseband unless you make the phone's PCB larger (which Apple obviously wasn't going to do).
Anand notes that while the MDM9600 is a 45nm process, the MDM9615 which is expected in 2012 is built on a 28nm process. This chip is 10x10nm, is voice enabled, and would likely fit. Qualcomm's roadmap shows the MDM9615 arriving in Q2 2012.
Also, there have reportedly been problems at TSMC and Global Foundries in making the switch from 45nm to 28nm and Anand suggests these setbacks affected the smartphone's release schedule.
"I suspect that an aggressive 28nm roadmap that didn't pan out probably caught a lot of SoC and smartphone vendors in a position where they couldn't ship what they wanted to in 2011."
Read More