Operating 4G network in 915 MHz unlicensed ISM band

[kozuch]

This is not an issue but rather a question. Since it has been said that it is legal to operate 4G network in 915 ISM band in the US (and most likely also in other parts of the world with similar regulatios) I wonder how this could technically be done. The idea is to use srsRAN eNodeB+EPC to serve rural population which would access it with affordable COTS UEs.

I have 2 main conserns:

1. Interference

Is LTE able to handle radio interference that may be present from other ISM equipment (probably various fixed access WISP equipment + some IoT). If so, in what technical way (modulation downgrade?) and to a what degree can it be handled (% of channel utilization)? I saw there is a standard for LTE in unlicensed spectrum but dont know how this is relevant here.

2. Spectrum usage

The ISM band is 902-928 MHz so the overlap with LTE band 8 is 902-915 (uplink) and 925-928 (downlink) where DL is only 3 MHz. I am new to LTE and dont really know in detail how the LTE channels works - is there a way to use more bandwidth for downlink (using lower than 925 MHz or carrier aggregation etc.?) Is there any chance the 915-925 MHz part could be used somehow with COTS UEs? I guess for srsRAN UEs there would be a way with possible custom code but SDR UEs are rather expensive for intented use case.

Thanks for any comments on the topic.