With the explosive growth of mobile communication and the rapid development of mobile data traffic

many countries around the world began the commercial LTE process.With the further development of LTE

part of the spectrum used by the existing 2G network will be assigned to LTE.It will bring the coexistence interference between LTE and GSM systems

in order to ensure that LTE and GSM systems can both be normally operated

the development of the adjacent channel coexistence protection program is one of the key issues that need to be addressed by refarming technology.In this paper

we deeply study the adjacent channel interference between LTE and GSM systems

put forward the guard-band between the coexistence of different standard of LTE and GSM systems and lay a solid foundation of refarming technology.