I'm sure the big operators are more than happy to limit possible competition, but that's not the primary reason why LTE-LAA is assisted.
First, LTE-U with its fixed pattern is a quick n' dirty non standard proposal. It's not even acceptable everywhere, as some countries (Europe for example) do require LBT in the 5 GHz band, which LTE-U does not do. So I'll skip that part.
For the 3GPP standard LTE-LAA, a fundamental reason that it requires a primary channel in licensed bands is that the way LTE works does require an always-on, reserved channel. This is the way LTE do works in licensed bands: the channel is fully reserved for LTE, under full eNB control. Changing this fundamental assumption would be a major breakage, and much much more effort. The result would be very different. Whereas using LTE carrier aggregation, with a primary channel in a licensed band and using the unlicensed 5 GHz band for downlink only (UL has some added challenges that makes it unpractical) secondary channel(s) with LBT is not too difficult. It's an incremental changes, but does not require breaking a fundamental assumption.
And in this case, LTE-LAA could perform like other technologies (to be checked, but possible on principle).
So even if it fits with the operator wishes, the assisted part is also the sane way to add 5 GHz support to LTE from a pure technological point of view.
>> Changing this fundamental assumption would be a major breakage, and much much more effort.
That's non of the concern of the unlicensed spectrum.The LTE-LAA guys should do their work and come prepared for what is common in the unlicensed world. Not the other way around.
And open competitiveness is key in the unlicensed band.
Unfortunately, this is not set in law. And really, that's the level where this should be enforced. You can count on firms to pursue their own self interest to the extent allowed by the law. I'm not saying that's good, I'm saying that's what happens BTW (don't shoot the messenger ;).
Here, cellular operators are seeing all this "free" spectrum, and cellular equipment makers are building a path to enable them to use it in a practical way for them, and sell their wares in the process. All legally, as the law is today.
BTW, there are precedents. In the IoT/M2M space Sigfox uses an unlicensed band around 900 MHz (from memory), and you can't buy their base stations: they make them for their own use, as their business is to be an operator. If you want to compete with them, you need to develop your own equipment based on a different scheme. WiFi and BT are the best known techs working in unlicensed bands, but there are proprietary systems too.
The legal constraints on the unlicensed bands are varying depending on country. But as far as I know the strictest constraints are:
- limited transmission power (LTE-LAA won't be allowed to shout above others at 5 GHz, at least where this constraint exists);
- requirements to do listen-before-talk (LBT), at least in Europe (but not in the US);
- limit on the amount of consecutive time a given device can hold the medium (5 ms max.).
LTE-LAA (not LTE-U) will be able to comply with all of this. In this sense, strictly limited to legal constraints, it will behave as is common in the 5 GHz band. To put more restrictions would need to happen at a legal level. And not surprisingly, there's intense lobbying on this topic happening right now from all parties (Google paper is part of this). To be followed...
First, LTE-U with its fixed pattern is a quick n' dirty non standard proposal. It's not even acceptable everywhere, as some countries (Europe for example) do require LBT in the 5 GHz band, which LTE-U does not do. So I'll skip that part.
For the 3GPP standard LTE-LAA, a fundamental reason that it requires a primary channel in licensed bands is that the way LTE works does require an always-on, reserved channel. This is the way LTE do works in licensed bands: the channel is fully reserved for LTE, under full eNB control. Changing this fundamental assumption would be a major breakage, and much much more effort. The result would be very different. Whereas using LTE carrier aggregation, with a primary channel in a licensed band and using the unlicensed 5 GHz band for downlink only (UL has some added challenges that makes it unpractical) secondary channel(s) with LBT is not too difficult. It's an incremental changes, but does not require breaking a fundamental assumption. And in this case, LTE-LAA could perform like other technologies (to be checked, but possible on principle).
So even if it fits with the operator wishes, the assisted part is also the sane way to add 5 GHz support to LTE from a pure technological point of view.