This document discloses a solution for performing anti-jamming procedures. According to an aspect, a method for a terminal device comprises: receiving a first reference signal allocation from an access node, wherein the first reference signal is unique to the terminal device in a cell managed by the access node; receiving a second reference signal allocation from the access node, wherein the second reference signal is shared with at least one other terminal device in the cell; causing transmission of payload data together with the first reference signal according to a regular transmission pattern; and breaking the regular transmission pattern by transmitting dummy data together with the second reference signal in a time-frequency resource shared with the at least one other terminal device.