Embodiments of the present disclosure relate to methods and devices for reference signal (RS) transmission. In example embodiments, a method implemented in a network device is provided. According to the method, a first set of RS resources are determined for RS transmission by the network device. The first set of RS resources are associated with a first number of RS ports to be used for RS transmission and correspond to a first set of resource elements (REs) interpolated with unused REs infrequency domain. A first RS configuration for RS transmission is generated based on the first set of RS resources. Information on the first RS configuration is transmitted to a terminal device served by the network device.