A friend of mine pointed me to this document which gives an overview of which portions of frequencies have been allocated to which mobile operators in Europe. I've been looking for such a document for quite a while now as it can give interesting insights into which options mobile operators in Europe have when it comes to frequency bands in Europe. Here's what I think:
The 900 MHz band
In total, there are 35 MHz available in this band, which are typically shared for GSM today by two to four operators. Even if only two operators use this band, each operator has typically less than 10 MHz of consecutive bandwidth available here. For LTE that means that the best that an operator can do in this band is to deploy a 5 MHz LTE carrier. For most operators, that's unlikely though as the remaining 900 MHz chunks they already own are probably not enough to ensure GSM in-house coverage with enough capacity. So, most operators could only deploy a 1.25 MHz LTE carrier in this band. I wonder if that's attractive as the achievable bandwidth is severely limited. But maybe for deep in-house coverage, it's better than nothing!? Also, there's no possibility to buy additional chunks in this "prime" band, it's all allocated.
The 1800 MHz band
This game is a bit different as in total, 75 MHz were assigned to GSM here and many "second wave" GSM operators in Europe got assigned chunks of more than 10 MHz. Also, in many countries, not all of the 75 MHz have been sold so some operators might be thinking of acquiring some of the so far unused chunks to start with a 5 MHz or 10 MHz LTE carrier here.
The 2100 MHz band
This is the 3G UMTS band in Europe with a total of 60 MHz. In most countries, each operator has a 10 MHz chunk and probably only uses 5 MHz of that for a single 3G carrier. Also, there is some of that bandwidth still available, e.g. due to alternative 3G carriers having given up after they paid a bit too much for the licenses back in the year 2000. So scenarios for this band could be that some operators will start with a 5 MHz carrier in this band or try to by additional spectrum to be able to operate a 10 MHz carrier. Since there is not enough bandwidth left for all, let's see if a price fight breaks out again like in the early 3G days. Doubtful but I see more interested parties then available chunks.
The 2600 MHz band
In most countries, this part of the spectrum is still up for grabs. The issue here is that in-house coverage would be even more difficult to achieve than with the 2100 MHz band. Lots of space for 10 MHz+ carriers.
Do 5 MHz carriers make sense?
This is the big question. With MIMO, the performance of LTE with a 5 MHz carrier is similar as HSPA+ with MIMO. Even if operators do not choose to upgrade their HSPA networks to MIMO, I wonder if the speed difference is big enough to justify the expense to go to LTE compared to upgrading their already existing HSPA base station with a second carrier.
So there are four frequency options for LTE in Europe: 900, 1800, 2100 and 2600, each with benefits and drawbacks. Different operators will surely have different strategies, including using several bands at once, so it's likely that single band LTE devices are likely not to be a winner. Supporting all four frequency bands with MIMO, which requires at least two antennas per band in a single device, however, is going to be difficult to achieve. And on top of that we haven't even talked yet about the 700, 850, 1900 MHz band in the US.
I guess both first movers and followers in this space will have difficult choices to make when it comes to frequency bands. As always, comments are welcome.