A signal transmission method, comprising: determining, by a device, a target channel access mechanism from at least two channel access mechanisms, wherein the at least two channel access mechanisms are candidate channel access mechanisms for the device to transmit a signal on an unlicensed carrier; and performing, by the device, a channel sensing on the unlicensed carrier according to the target channel access mechanism, to determine an availability of a time frequency resource to be used by the device for performing the signal transmission, wherein the signal comprises at least two reference signals, the at least two reference signals comprise a first reference signal and a second reference signal, and the first reference signal is located before the second reference signal on a time domain, wherein a duration of a time domain resource occupied by the signal is used for determining, by the device, the target channel access mechanism from the at least two channel access mechanisms, wherein a first type of channel access mechanism is channel sensing with a deterministic sensing duration; wherein a second type of channel access mechanism is channel sensing based on a contention window; wherein determining, by the device, the target channel access mechanism from the at least two channel access mechanisms, comprises: determining, by the device, that the target channel access mechanism is the first type of channel access mechanism, when the duration of the time domain resource occupied by the signal is less than or equal to a first time duration; and determining, by the device, that the target channel access mechanism is the second type of channel access mechanism, when the duration of the time domain resource occupied by the signal is larger than the first time duration, and wherein the first time duration is 1 millisecond. determining, by a device, a target channel access mechanism from at least two channel access mechanisms, wherein the at least two channel access mechanisms are candidate channel access mechanisms for the device to transmit a signal on an unlicensed carrier; and performing, by the device, a channel sensing on the unlicensed carrier according to the target channel access mechanism, to determine an availability of a time frequency resource to be used by the device for performing the signal transmission, wherein the signal comprises at least two reference signals, the at least two reference signals comprise a first reference signal and a second reference signal, and the first reference signal is located before the second reference signal on a time domain, wherein a duration of a time domain resource occupied by the signal is used for determining, by the device, the target channel access mechanism from the at least two channel access mechanisms, wherein a first type of channel access mechanism is channel sensing with a deterministic sensing duration; wherein a second type of channel access mechanism is channel sensing based on a contention window; wherein determining, by the device, the target channel access mechanism from the at least two channel access mechanisms, comprises: determining, by the device, that the target channel access mechanism is the first type of channel access mechanism, when the duration of the time domain resource occupied by the signal is less than or equal to a first time duration; and determining, by the device, that the target channel access mechanism is the second type of channel access mechanism, when the duration of the time domain resource occupied by the signal is larger than the first time duration, and wherein the first time duration is 1 millisecond. determining, by the device, that the target channel access mechanism is the first type of channel access mechanism, when the duration of the time domain resource occupied by the signal is less than or equal to a first time duration; and determining, by the device, that the target channel access mechanism is the second type of channel access mechanism, when the duration of the time domain resource occupied by the signal is larger than the first time duration, and wherein the first time duration is 1 millisecond.