What do you check when you are buying new smartphone? Do you check only memory, CPU and camera parameters? Or maybe you check also network capability parameters? Statistics show that people want to buy new fancy 4G (LTE), even if they are not in LTE coverage area.
Let’s assume that you are in range of LTE basestation. Do you know that different LTE equipment offers different throughput level? 3GGP organization defines UE (User Equipment) categories of LTE devices. The most popular categories are 3, 4 and 6. What does it mean? Shortly, UE category 3 provides 100 Mbps peak throughput in downlink direction. In case of category 4 you are able to achieve up to 150 Mbps and in case of category 6 it is 300 Mbps!
The newest iPhone and Samsung Galaxy smartphones are category 6, so you can buy mobile device which is able to download data with 300 Mbps speed! Where is the catch? Unfortunately in this case, the bottleneck is the carrier network 🙁
In order o achieve the full potential of UE we have to be connected to 20 MHz cell. In case of category 6 we need total 40 MHz spectrum (e.g. 2×20 MHz) and carrier aggregation technology (it is possible in LTE-A (Advance) networks).
How does look the situation in India? Most of cells is 5 MHz and in most cases you are not able to work with the 64QAM modulation and you use 16QAM. Throughput for 16QAM is 1.5 times worse than in case of 64QAM. Ofcourse in case of 5 MHz cell the peak throughput is 4 times lower than for 20 MHz. The math is simple: 150 Mbps/4/1.5 = 25 Mbps. This is the reason why most people in India achieve approx 20 Mbps throughput in LTE networks. We also loose couple Mbps because of TD-LTE (Time Division), because operators do not want to discriminate uplink direction completely.