A method for cell reselection comprising: determining, by an apparatus for cell reselection from a source cell side, whether a User Equipment, UE, camping on the source cell side meets an initial reselection condition for reselecting to camp on a target cell side; when determining that the UE camping on the source cell side meets the initial reselection condition for reselecting to camp on the target cell side, searching, by the apparatus for cell reselection from the source cell side, a list of reselection parameter thresholds maintained at the source cell side for a target-to-source, T-to-S, reselection parameter threshold for the UE camping on the target cell side to reselect to camp on the source cell side; when there is no such threshold, allowing the UE camping on the source cell side to reselect to camp on the target cell side; and when there is such a threshold, further determining whether a source cell side reselection parameter corresponding to the T-to-S reselection parameter threshold measured for the source cell side by the UE is less than or no greater than the T-to-S reselection parameter threshold; when the source cell side reselection parameter is less than or no greater than the T-to-S reselection parameter threshold, allowing the UE camping on the source cell side to reselect to camp on the target cell side; otherwise when the source cell side reselection parameter is greater than the T-to-S reselection parameter threshold, suppressing the reselection to the target cell side; and upon allowing the UE camping on the source cell side to reselect to camp on the target cell side, notifying, by the apparatus for cell reselection from the source cell side, the target cell side of a source-to-target, S-to-T, reselection parameter threshold for the UE camping on the source cell side to reselect to camp on the target cell side, wherein the source cell side and the target cell side belong respectively to different communication systems. determining, by an apparatus for cell reselection from a source cell side, whether a User Equipment, UE, camping on the source cell side meets an initial reselection condition for reselecting to camp on a target cell side; when determining that the UE camping on the source cell side meets the initial reselection condition for reselecting to camp on the target cell side, searching, by the apparatus for cell reselection from the source cell side, a list of reselection parameter thresholds maintained at the source cell side for a target-to-source, T-to-S, reselection parameter threshold for the UE camping on the target cell side to reselect to camp on the source cell side; when there is no such threshold, allowing the UE camping on the source cell side to reselect to camp on the target cell side; and when there is such a threshold, further determining whether a source cell side reselection parameter corresponding to the T-to-S reselection parameter threshold measured for the source cell side by the UE is less than or no greater than the T-to-S reselection parameter threshold; when the source cell side reselection parameter is less than or no greater than the T-to-S reselection parameter threshold, allowing the UE camping on the source cell side to reselect to camp on the target cell side; otherwise when the source cell side reselection parameter is greater than the T-to-S reselection parameter threshold, suppressing the reselection to the target cell side; and when the source cell side reselection parameter is less than or no greater than the T-to-S reselection parameter threshold, allowing the UE camping on the source cell side to reselect to camp on the target cell side; otherwise when the source cell side reselection parameter is greater than the T-to-S reselection parameter threshold, suppressing the reselection to the target cell side; and upon allowing the UE camping on the source cell side to reselect to camp on the target cell side, notifying, by the apparatus for cell reselection from the source cell side, the target cell side of a source-to-target, S-to-T, reselection parameter threshold for the UE camping on the source cell side to reselect to camp on the target cell side, wherein the source cell side and the target cell side belong respectively to different communication systems.