Samsung Galaxy S4-GT I9507- how does it support LTE?
So I have been using ‘Optus Samsung Galaxy S4 GT I9507’ Smartphone for LTE UE Validation testing. Questions is-how do we choose the Smartphone for LTE Pre-Post Network Launch Validation?
Let's start with the kind of LTE Band support required. Assumingly we need to test LTE for Band 2300 or Band 40, we need to check whether the Optus S4 supports this LTE band or not.
The best way to do this is to visit Manufacturer’s webpage. Although, I thought the phone is TDD LTE, the story is quite different.
How do we check, if a particular Smartphone supports particular LTE Bands? There's no easy way to do this, but there's a Google Play Store App- 'CPU Z', which tells you more detail about underlying SoC (Read: System on Chip) hardware. Based on the information you need to investigate further.
Other way is to visit the manufacturer’s webpage which enlists devices specs, as we did earlier, and check, if there's any country specific LTE Band support for device model is available. If you don't find such information (specific to your country’s LTE band support or model launched), I guess then you need to wait till that particular model is launched with country specific LTE support.
Samsung S4 smartphone, which I'm using, is 'Optus LTE' device. So naturally, the starting point is to see, if Optus has launched LTE and if yes, which are the smartphones available in Australian market, which supports Optus LTE bands. After researching some information, I could find out that Optus has launched LTE on both FDD and TDD modes and Samsung Galaxy S4 is one of the devices available, which supports both LTE modes.
So now, I could find out that the Smartphone Galaxy S4, which I’m using for UE validation testing, supports both LTE TDD and FDD modes ('Band 3' and '40') of operations.
Now let's dig down little dipper.
My 'CPU Z' mobile App, which we talked earlier, shows that Galaxy S4 GT I9507 has Qualcomm's Snapdragon 600 series SoC inside. Interestingly this brought one more question to my mind- how does S4 supports LTE/HSPA/3G/GSM Cellular connectivity, as SD 600 series SoC doesn't have Cellular Chipset for connectivity (as part of SoC).
Why this is relevant to find out?
Just because, as per Optus data on phone, S4 does support LTE Band 3 and Band 40 both, but as per our investigation of SoC, there's no cellular connectivity chipset available, as a part of 600 SoC Architecture.
Now, we need to dig down dipper for this. I decided to take help of AnandTech, the best source on Smartphone SoC and hardware testing.
As per AnandTech, Samsung Galaxy S4 is a Cat 3 LTE device, which supports upto 100 Mbps data speeds on downlink (e-NodeB to UE) and 50 Mbps on Uplink (UE to e-NodeB). The device's LTE band support varies from market to market. But we already know that the device, which we have, is Optus S4 and supports LTE Band 3 and Band 40, both.
But we haven't got the answer yet. How does S4 GT I9507 support cellular connectivity?
I looked at data available from 'CPU Z' Android App. In the system tab of app's interface, I observed that S4 has 'System board' of Qualcomm's MSM8960 chipset. Qualcomm has launched MSM (Mobile Station Modem) 8960 Chipset in year 2010, which not only support CDMA-EVDO bands, but also multi-carrier HSPA+ and LTE networks. A little dig down dipper shows how Qualcomm support LTE inside S4 GT I9507.
Why do we need separate chipset (MSM8960) for Cellular Connectivity? If you see this page, you would find that Snapdragon 600 SoC, which Optus Galaxy S4 is using, doesn't have modem support available. So to provide cellular connectivity (via modem), 600 SoC is using MSM8960 chipset, which provides complete integrated cellular connectivity solution.