Data transmission method, device, and system

A data transmission method, comprising:

• obtaining, by a second device, grouping information, wherein the grouping information is used to indicate information of grouping N physical resource blocks (PRBs) into M PRB groups, wherein N is an integer greater than 110, and M is a positive integer;
• receiving, by the second device, data on a physical resource that corresponds to the N PRBs;
• and
• demodulating, by the second device, the data according to the grouping information.

A first device, comprising a processor, a memory, a bus,

• and a transceiver, wherein the processor, the memory, and the transceiver are connected to each other by using the bus, wherein
• the transceiver is configured to obtain grouping information, wherein the grouping information is used to indicate information of grouping N physical resource blocks (PRBs) into M PRB groups, wherein N is an integer greater than 110, and M is a positive integer;
• the processor is configured to perform modulation and coding by using a transport block size (TBS) that corresponds to each of the M PRB groups obtained by the transceiver, to generate modulation symbols;
• and
• the transceiver is further configured to transmit the modulation symbols generated by the processor to a second device by using a physical resource that corresponds to the N PRBs.