The present disclosure relates to signalling of reference signals for Multi Input Multi Output (MIMO) transmission schemes. A method embodiment for generating reference signals for use between a mobile terminal 10 and an access node 20 in a cellular communication network 100 comprises receiving, by the mobile terminal 10, a cyclic shift set indicator; selecting, from a group of cyclic shift sets, a cyclic shift set based on the received cyclic shift set indicator, each cyclic shift set comprising at least two parameters each indicating a cyclic shift; and generating, based on at least two parameters of the selected cyclic shift set, at least two orthogonal reference signals for at least two layers of a Single User Spatial Multiplexing transmission scheme to be simultaneously transmitted. A further method embodiment comprises selecting, from a plurality of groups of cyclic shift sets, a group of cyclic shift sets based on at least one of a transmission rank, being the number of layers to be simultaneously transmitted, and a number of configured antennas of the mobile terminal 10.