The introduction of Device-to-Device（D2D）technology into the LTE systems in a non-orthogonal way of reusing resources may bring about interferences

i.e.mutual interferences between the cellular users and the D2Dusers.In the D2Dsystems

cross-layer resource optimization can cope with instantaneous channel worsening arising from the interferences for the cellular users

thus improving their average spectral efficiency and increasing the system capacity.This thesis studies a link-adaptive cross-layer optimization scheme for the D2Dsystem

which combines the adaptive modulation and coding technology in the physical layer with the auto repeat request technology in the data link layer

aiming at lowering the interferences arising from the introduction of the D2Dtechnology.Simulation results indicate that in a single cell scenario with 4cellular users and 4 pair of D2Dusers

the total capacity of the D2Dcommunication system is increased by about 5% when the link-adaptive crosslayer optimization scheme is adopted.