Example methods and systems for adapting fourth generation (4G) and/or fifth generation (5G) cellular downlink channels in the presence of non-stationary interference are disclosed. An example method, implemented by one or more processors of a cellular base station, includes: receiving, from a user equipment (UE) radio, channel state information (CSI) for a cellular downlink channel between the cellular base station and the UE; determining a signal to interference and noise ratio (SINR) offset based upon the CSI, and a target block error rate (BLER); determining a variance of the SINR offset that represents one or more characteristics of the non-stationary interference; and determining the target BLER based upon the variance of the SINR offset such that the cellular downlink channel adapts to the presence of the non-stationary interference.