Abstract: A method of CSI resource allocation in a subband full duplex (SBFD) system is disclosed. The method can include receiving a channel state information (CSI) resource configuration from a base station in a subband full duplex (SBFD) system, the CSI resource configuration being associated with one or more CSI reference signal (CSI-RS) resource set including at least one CSI-RS resource, the CSI resource configuration indicating a first CSI-RS resource distribution and a second CSI-RS resource distribution, each CSI-RS resource distribution indicates one or more frequency domain starting position and one or more total number of resource blocks of one or more partition of the respective CSI-RS resource set in CSI transmission slots, performing a channel measurement based on the one or more CSI-RS resource set and the CSI resource configuration, and transmitting a CSI report to the base station based on the channel measurement.