What is Licensed Shared Access (LSA) concept
LSA concept aims at allowing new licensed users on spectrum bands that already encompass incumbent spectrum users with spectrum sharing that provides a certain quality of service for both the entrants and the incumbents.
* Incumbent defines the part of the spectrum, license duration and area that is available.
* License sharing agreement is set between incumbent and LSA Licensee.
* Spectrum regulator issues the license to LSA Licensee.
* Incumbent can reclaim the spectrum back on demand for own business -> “dynamic” behavior
So in short LSA is a concept by which two operator can share the supply of spectrum based on need and maximize the use of spectrum.
Now coming to the point,
As far as I know LSA is more legal restriction by law then a technological challenge and I think only Europe has some policy around it called "shared use of Europe's radio spectrum" but does not seems that there is any installation.