A communication method in a 5G communications system supporting a grant-free transmission manner of uplink data, comprising: detecting, by a network device in a first time unit, a reference signal and/or data that are/is sent by a terminal device to the network device in a second time unit; and sending, by the network device, first indication information in a third time unit after the first time unit, wherein the first indication information is used to indicate a resource for sending the data by the terminal device; wherein the reference signal carries first information, the first information is used to indicate that the reference signal is a reference signal sent by the terminal device to the network device for an N th time, and N is a positive integer greater than or equal to 1; and if the second time unit is less than a time unit in which the terminal device sends the reference signal to the network device for an L th time, the third time unit is the time unit in which the terminal device sends the reference signal to the network device for the L th time, or the third time unit is an X th time unit after the time unit in which the terminal device sends the reference signal to the network device for the L th time; or if the second time unit is greater than or equal to a time unit in which the terminal device sends the reference signal to the network device for an L th time, the third time unit is an X th time unit after the first time unit, and both L and X are positive integers greater than or equal to 1; or wherein the reference signal carries second information, and the second information is used to indicate whether the reference signal is a reference signal sent by the terminal device to the network device for a first time; and if the reference signal is a reference signal sent by the terminal device to the network device for the first time, the third time unit is a time unit in which the terminal device sends the reference signal to the network device for an L th time, or the third time unit is an X th time unit after the time unit in which the terminal device sends the reference signal to the network device for the L th time, and both L and X are positive integers greater than or equal to 1; or if the reference signal is not a reference signal sent by the terminal device to the network device for the first time, the third time unit is an M th time unit after the first time unit, M is a positive integer greater than or equal to 1, and a value of M is the same as a value of L, or a value of M is a difference between L and 1. detecting, by a network device in a first time unit, a reference signal and/or data that are/is sent by a terminal device to the network device in a second time unit; and sending, by the network device, first indication information in a third time unit after the first time unit, wherein the first indication information is used to indicate a resource for sending the data by the terminal device; wherein the reference signal carries first information, the first information is used to indicate that the reference signal is a reference signal sent by the terminal device to the network device for an N th time, and N is a positive integer greater than or equal to 1; and if the second time unit is less than a time unit in which the terminal device sends the reference signal to the network device for an L th time, the third time unit is the time unit in which the terminal device sends the reference signal to the network device for the L th time, or the third time unit is an X th time unit after the time unit in which the terminal device sends the reference signal to the network device for the L th time; or if the second time unit is greater than or equal to a time unit in which the terminal device sends the reference signal to the network device for an L th time, the third time unit is an X th time unit after the first time unit, and both L and X are positive integers greater than or equal to 1; or wherein the reference signal carries second information, and the second information is used to indicate whether the reference signal is a reference signal sent by the terminal device to the network device for a first time; and if the reference signal is a reference signal sent by the terminal device to the network device for the first time, the third time unit is a time unit in which the terminal device sends the reference signal to the network device for an L th time, or the third time unit is an X th time unit after the time unit in which the terminal device sends the reference signal to the network device for the L th time, and both L and X are positive integers greater than or equal to 1; or if the reference signal is not a reference signal sent by the terminal device to the network device for the first time, the third time unit is an M th time unit after the first time unit, M is a positive integer greater than or equal to 1, and a value of M is the same as a value of L, or a value of M is a difference between L and 1.