A data transmission method performed by a terminal device, the method comprising: • receiving (S210, S230) indication information from a network device, wherein the indication information is used to determine resources occupied by N groups of cell-specific reference signals, CRSs, and N is a natural number greater than or equal to 2, wherein ∘ the indication information is an index of a physical downlink shared channel resource element mapping and a quasi-co-location indicator, PQI, and the PQI indicates information about quantities of antenna ports and frequency offsets of the N groups of CRSs, ▪ wherein each group of CRSs among the N groups of CRSs has a corresponding quantity of antenna ports and a corresponding frequency offset, ▪ wherein each frequency offset indicates a location of a resource element, RE, to which a CRS is mapped in a frequency domain resource, the CRS is one CRS in a CRS group among the N groups of CRSs, ▪ wherein any two groups of CRSs among the N groups of CRSs are different from each other in at least one of the quantity of antenna ports or the frequency offset,; • determining, based on the indication information, the resources that are occupied by the N groups of CRSs; • receiving data including codewords from the network device in a physical downlink shared channel, PDSCH, based on the resources that are occupied by the N groups of CRSs, wherein the data are not mapped on REs to which a part of the resources that are occupied by the N groups of CRSs are mapped. • receiving (S210, S230) indication information from a network device, wherein the indication information is used to determine resources occupied by N groups of cell-specific reference signals, CRSs, and N is a natural number greater than or equal to 2, wherein ∘ the indication information is an index of a physical downlink shared channel resource element mapping and a quasi-co-location indicator, PQI, and the PQI indicates information about quantities of antenna ports and frequency offsets of the N groups of CRSs, ▪ wherein each group of CRSs among the N groups of CRSs has a corresponding quantity of antenna ports and a corresponding frequency offset, ▪ wherein each frequency offset indicates a location of a resource element, RE, to which a CRS is mapped in a frequency domain resource, the CRS is one CRS in a CRS group among the N groups of CRSs, ▪ wherein any two groups of CRSs among the N groups of CRSs are different from each other in at least one of the quantity of antenna ports or the frequency offset,; ▪ wherein each group of CRSs among the N groups of CRSs has a corresponding quantity of antenna ports and a corresponding frequency offset, ▪ wherein each frequency offset indicates a location of a resource element, RE, to which a CRS is mapped in a frequency domain resource, the CRS is one CRS in a CRS group among the N groups of CRSs, ▪ wherein any two groups of CRSs among the N groups of CRSs are different from each other in at least one of the quantity of antenna ports or the frequency offset,; • determining, based on the indication information, the resources that are occupied by the N groups of CRSs; • receiving data including codewords from the network device in a physical downlink shared channel, PDSCH, based on the resources that are occupied by the N groups of CRSs, wherein the data are not mapped on REs to which a part of the resources that are occupied by the N groups of CRSs are mapped.