TECHNICAL FIELD

The present invention relates to the field of wireless communications technologies, and in particular, to a data transmission method, an apparatus, and a system.

BACKGROUND

In a Long Term Evolution (LTE) system, data transmission between a base station and a terminal device is performed based on scheduling of the base station. Before receiving downlink data or sending uplink data, the terminal device receives scheduling information sent by the base station. The scheduling information may include a physical resource allocated to UE, for example, at least one of information about a time-frequency resource or information about a modulation and coding scheme configured for the UE. In addition, the base station may further add, to the scheduling information, information about a power control command related to uplink transmission of the UE. The scheduling information and the information about the power control command are collectively referred to as downlink control information (DCI).

In the LTE system, a transmission time interval (TTI) is a length of one subframe, that is, 1 ms. The base station only needs to send one piece of DCI in one subframe, to instruct the terminal device to receive or send one data packet (Packet data) with a TTI of 1 ms.

In the LTE system, a latency is one of important factors affecting user experience. Constantly emerging new services, such as a service related to the Internet of Vehicles, impose higher requirements on a latency. An existing transmission mechanism based on a TTI of one subframe or an existing transmission mechanism based on a TTI of 1 ms cannot satisfy a service latency requirement of a user.

SUMMARY

In view of this, embodiments of the present invention provide a data transmission method, an apparatus, and a system, to resolve a problem that a transmission mechanism based on a TTI of one subframe or a transmission mechanism based on a TTI of 1 ms cannot satisfy a service latency requirement of a user.

According to a first aspect, an embodiment of the present invention provides a base station, including:

a processing module, configured to determine a data transmission resource, where the data transmission resource is a short-TTI data transmission resource, and the short-TTI data transmission resource is less than a length of one subframe or is less than 1 ms in time domain; and

a transceiver module, configured to: send DCI to a terminal device, where the DCI is used to indicate the data transmission resource; and perform data transmission with the terminal device on the data transmission resource.

With reference to the first aspect, in a first possible implementation, the data transmission resource includes a time-domain transmission resource, and the processing module is specifically configured to:

determine a time-domain pattern, and select, from multiple time-domain elements included in the determined time-domain pattern, one time-domain element as the time-domain transmission resource; or

determine an starting symbol and a quantity of symbols of the time-domain transmission resource.

With reference to the first possible implementation of the first aspect, in a second possible implementation, the processing module is specifically configured to:

determine the time-domain pattern according to a system bandwidth, where a higher system bandwidth indicates a smaller quantity of symbols included in the selected time-domain element included in the time-domain pattern; or

determine the time-domain pattern according to an available short-TTI data transmission bandwidth, where a higher available short-TTI data transmission bandwidth indicates a smaller quantity of symbols included in the selected time-domain element included in the time-domain pattern, and the available short-TTI data transmission bandwidth is a bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to the first or the second possible implementation of the first aspect, in a third possible implementation, in the time-domain pattern:

each subframe includes two time-domain elements, a first time-domain element is located in the first slot, a second time-domain element is located in the second slot, and the time-domain elements do not include a symbol occupied by a legacy PDCCH; or

each subframe includes four time-domain elements; for a normal cyclic prefix CP, a first time-domain element is a set of symbols whose sequence numbers are {#0, #1, #2, #3}, a second time-domain element includes a set of symbols whose sequence numbers are {#4, #5, #6}, a third time-domain element is a set of symbols whose sequence numbers are {#7, #8, #9, #10}, and a fourth time-domain element is a set of symbols whose sequence numbers are {#11, #12, #13}; for an extended CP, every three consecutive symbols form one time-domain element, a first time-domain element is a set of symbols whose sequence numbers are {#0, #1, #2}, a second time-domain element is a set of symbols whose sequence numbers are {#3, #4, #5}, a third time-domain element is a set of symbols whose sequence numbers are {#6, #7, #8}, and a fourth time-domain element is a set of symbols whose sequence numbers are {#9, #10, #11}; and the time-domain elements do not include a symbol occupied for transmitting a PDCCH; or

for a normal CP, each subframe includes seven time-domain elements, and every two consecutive symbols form one time-domain element; for an extended CP, each subframe includes six time-domain elements, and every two consecutive symbols form one time-domain element; and the time-domain elements do not include a symbol occupied by a legacy PDCCH.

With reference to the first possible implementation of the first aspect, in a fourth possible implementation, the processing module is specifically configured to:

use a reference symbol as the starting symbol of the time-domain transmission resource, where the reference symbol is the first symbol occupied by the DCI, the last symbol occupied by the DCI, the kthsymbol following the first symbol occupied by the DCI, or the kthsymbol following the last symbol occupied by the DCI, and k is a positive integer; and

determine, according to a system bandwidth, the quantity of symbols of the time-domain transmission resource, where a higher system bandwidth indicates a smaller quantity of occupied symbols; or

determine, according to an available short-TTI data transmission bandwidth, the quantity of symbols of the time-domain transmission resource, where a higher available short-TTI data transmission bandwidth indicates a smaller quantity of occupied symbols, and the available short-TTI data transmission bandwidth is a bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the first to the fourth possible implementations of the first aspect, in a fifth possible implementation, an information bit that is used to indicate the time-domain transmission resource and that is in the DCI is null.

With reference to any one of the first aspect or the first to the fifth possible implementations of the first aspect, in a sixth possible implementation, the data transmission resource includes a frequency-domain transmission resource, and the processing module is specifically configured to:

determine that the frequency-domain transmission resource is the system bandwidth or the available short-TTI data transmission bandwidth, where the available short-TTI data transmission bandwidth is the bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the first aspect or the first to the fifth possible implementations of the first aspect, in a seventh possible implementation, the data transmission resource includes a frequency-domain transmission resource:

the processing module is further configured to: before determining the data transmission resource, determine a frequency-domain resource scheduling granularity, where the frequency-domain resource scheduling granularity is a minimum frequency-domain resource allocation unit used when the base station schedules the terminal device to perform the data transmission, and includes at least one resource block RB; and

the processing module is specifically configured to determine the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity.

With reference to the seventh possible implementation of the first aspect, in an eighth possible implementation, the processing module is specifically configured to:

determine the frequency-domain resource scheduling granularity according to the system bandwidth, where

the frequency-domain resource scheduling granularity satisfies at least one of the following rules:

when the system bandwidth is less than or equal to 10 RBs, the frequency-domain resource scheduling granularity is NRBRBs; when the system bandwidth is 11 to 26 RBs, the frequency-domain resource scheduling granularity is

NRB⁢⁢or⁢⁢⌊NRB2⌋⁢RBs;
when the system bandwidth is 27 to 63 RBs, the frequency-domain resource scheduling granularity is

⌊NRB2⌋⁢⁢or⁢⁢⌊NRB3⌋⁢⁢or⁢⁢⌊NRB4⌋⁢RBs;
or when the system bandwidth is 64 to 110 RBs, the frequency-domain resource scheduling granularity is

⌊NRB4⌋⁢⁢or⁢⁢⌊NRB5⌋⁢RBs;
where NR is a quantity of RBs included in the system bandwidth.

With reference to the seventh possible implementation of the first aspect, in a ninth possible implementation, the processing module is specifically configured to:

determine the frequency-domain resource scheduling granularity according to the available short-TTI data transmission bandwidth, where the available short-TTI data transmission bandwidth is the bandwidth that can be occupied by the short-TTI data transmission resource, and

the frequency-domain resource scheduling granularity satisfies at least one of the following rules:

when the available short-TTI data transmission bandwidth is less than or equal to 10 RBs, the frequency-domain resource scheduling granularity is NRBRBs; when the available short-TTI data transmission bandwidth is 11 to 26 RBs, the frequency-domain resource scheduling granularity is

NRB⁢⁢or⁢⁢⌊NRB2⌋⁢RBs;
when the available short-TTI data transmission bandwidth is 27 to 63 RBs, the frequency-domain resource scheduling granularity is

⌊NRB2⌋⁢⁢or⁢⁢⌊NRB3⌋⁢⁢or⁢⁢⌊NRB4⌋⁢RBs;
or when the available short-TTI data transmission bandwidth is 64 to 110 RBs, the frequency-domain resource scheduling granularity is

⌊NRB4⌋⁢⁢or⁢⁢⌊NRB5⌋⁢⁢RBs,
where NRBis a quantity of RBs included in the available short-TTI data transmission bandwidth.

With reference to any one of the seventh to the ninth possible implementations of the first aspect, in a tenth possible implementation, the processing module is specifically configured to:

use a size of the frequency-domain resource scheduling granularity as a size of the frequency-domain transmission resource; and

use a reference RB as an starting resource block RB of the frequency-domain transmission resource, where

the reference RB is the mthRB following the first RB occupied by the DCI or the mthRB following the last RB occupied by the DCI, and m is an integer greater than or equal to 0.

With reference to the sixth or the tenth possible implementation of the first aspect, in an eleventh possible implementation, an information bit that is used to indicate the frequency-domain transmission resource and that is in the DCI is null.

With reference to any one of the seventh to the ninth possible implementations of the first aspect, in a twelfth possible implementation,

the processing module is specifically configured to use a size of the frequency-domain resource scheduling granularity as a size of the frequency-domain transmission resource, where

the DCI includes information used to indicate a location of the frequency-domain transmission resource.

With reference to any one of the seventh to the ninth possible implementations of the first aspect, in a thirteenth possible implementation,

the processing module is specifically configured to use a reference RB as an starting RB of the frequency-domain transmission resource, where

the reference RB is the mthRB following the first RB occupied by the DCI or the mthRB following the last RB occupied by the DCI, and m is an integer greater than or equal to 0; and

the DCI includes information used to indicate a size of a bandwidth occupied by the frequency-domain transmission resource.

With reference to any one of the first aspect or the first to the thirteenth possible implementations of the first aspect, in a fourteenth possible implementation, the processing module is further configured to: before determining the data transmission resource, when at least one of the following conditions is satisfied, determine that the data transmission resource used to perform the data transmission with the terminal device is the short-TTI data transmission resource:

a latency requirement of a service currently used by the terminal device is less than a specified latency threshold; or

the system bandwidth is greater than a specified bandwidth threshold.

With reference to the fourteenth possible implementation of the first aspect, in a fifteenth possible implementation, the transceiver module is further configured to:

after the processing module determines that the data transmission resource used to perform the data transmission with the terminal device is the short-TTI data transmission resource, and before the processing module determines the data transmission resource, send higher layer signaling or physical layer signaling to the terminal device, to indicate to the terminal device that:

the data transmission resource used to perform the data transmission between the base station and the terminal device is the short-TTI data transmission resource.

With reference to any one of the first aspect or the first to the fifteenth possible implementations of the first aspect, in a sixteenth possible implementation,

the processing module is further configured to: before determining the data transmission resource, determine the available short-TTI data transmission resource; and

the transceiver module is further configured to: after the processing module determines the available short-TTI data transmission resource, and before the processing module determines the data transmission resource, send, to the terminal device, information indicating the available short-TTI data transmission resource.

According to a second aspect, an embodiment of the present invention provides a terminal device, including:

a transceiver module, configured to receive DCI sent by a base station, where the DCI is used to indicate a data transmission resource; and

a processing module, configured to determine the data transmission resource according to the DCI, where the data transmission resource is a short-TTI data transmission resource, and the short-TTI data transmission resource is less than a length of one subframe or is less than 1 ms in time domain, where

the transceiver module is further configured to perform data transmission with the base station on the data transmission resource.

With reference to the second aspect, in a first possible implementation, the data transmission resource includes a time-domain transmission resource, and the processing module is specifically configured to:

determine a time-domain pattern, and determine, according to the DCI and in multiple time-domain elements included in the determined time-domain pattern, one time-domain element as the time-domain transmission resource; or

determine, according to the DCI, an starting symbol and a quantity of symbols of the time-domain transmission resource.

With reference to the first possible implementation of the second aspect, in a second possible implementation, the processing module is specifically configured to:

if the data transmission is downlink data transmission, determine that a time-domain element occupied by the DCI is the time-domain transmission resource; or

if the data transmission is uplink data transmission, determine that a time-domain element in which the kthsymbol following the first symbol occupied by the DCI or the kthsymbol following the last symbol occupied by the DCI is located is the time-domain transmission resource.

With reference to the first or the second possible implementation of the second aspect, in a third possible implementation, the processing module is specifically configured to:

determine the time-domain pattern according to a system bandwidth, where a higher system bandwidth indicates a smaller quantity of symbols included in the time-domain element included in the determined time-domain pattern; or

determine the time-domain pattern according to an available short-TTI data transmission bandwidth, where a higher available short-TTI data transmission bandwidth indicates a smaller quantity of symbols included in the time-domain element included in the determined time-domain pattern, and the available short-TTI data transmission bandwidth is a bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the first to the third possible implementations of the second aspect, in a fourth possible implementation, in the time-domain pattern:

each subframe includes two time-domain elements, a first time-domain element is located in the first slot, a second time-domain element is located in the second slot, and the time-domain elements do not include a symbol occupied by a legacy PDCCH; or

each subframe includes four time-domain elements; for a normal cyclic prefix CP, a first time-domain element includes a set of symbols whose sequence numbers are {#0, #1, #2, #3}, a second time-domain element includes a set of symbols whose sequence numbers are {#4, #5, #6}, a third time-domain element includes a set of symbols whose sequence numbers are {#7, #8, #9, #10}, and a fourth time-domain element includes a set of symbols whose sequence numbers are {#11, #12, #13}; for an extended CP, every three consecutive symbols form one time-domain element, a first time-domain element includes a set of symbols whose sequence numbers are {#0, #1, #2}, a second time-domain element includes a set of symbols whose sequence numbers are {#3, #4, #5}, a third time-domain element includes a set of symbols whose sequence numbers are {#6, #7, #8}, and a fourth time-domain element includes a set of symbols whose sequence numbers are {#9, #10, #11}; and the time-domain elements do not include a symbol occupied for transmitting a PDCCH; or

for a normal CP, each subframe includes seven time-domain elements, and every two consecutive symbols form one time-domain element; for an extended CP, each subframe includes six time-domain elements, and every two consecutive symbols form one time-domain element; and the time-domain elements do not include a symbol occupied by a legacy PDCCH.

With reference to the first possible implementation of the second aspect, in a fifth possible implementation, the processing module is specifically configured to:

determine that the starting symbol of the time-domain transmission resource is a reference symbol, where the reference symbol is the first symbol occupied by the DCI, the last symbol occupied by the DCI, the kthsymbol following the first symbol occupied by the DCI, or the kthsymbol following the last symbol occupied by the DCI, and k is a positive integer; and

determine, according to a system bandwidth, the quantity of symbols of the time-domain transmission resource, where a higher system bandwidth indicates a smaller quantity of occupied symbols; or determine, by the terminal device according to an available short-TTI data transmission bandwidth, the quantity of symbols of the time-domain transmission resource, where a higher available short-TTI data transmission bandwidth indicates a smaller quantity of occupied symbols, and the available short-TTI data transmission bandwidth is a bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the first to the fifth possible implementations of the second aspect, in a sixth possible implementation, an information bit that is used to indicate the time-domain transmission resource and that is in the DCI is null.

With reference to any one of the second aspect or the first to the sixth possible implementations of the second aspect, in a seventh possible implementation, the data transmission resource includes a frequency-domain transmission resource, and the processing module is specifically configured to:

determine that the frequency-domain transmission resource is the system bandwidth or the available short-TTI data transmission bandwidth, where

the available short-TTI data transmission bandwidth is the bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the second aspect or the first to the sixth possible implementations of the second aspect, in an eighth possible implementation, the data transmission resource includes a frequency-domain transmission resource:

the processing module is further configured to: before determining the data transmission resource, determine a frequency-domain resource scheduling granularity, where the frequency-domain resource scheduling granularity is a minimum frequency-domain resource allocation unit used when the base station schedules the terminal device to perform the data transmission, and includes at least one resource block RB; and

the processing module is specifically configured to determine the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity and the DCI.

With reference to the eighth possible implementation of the second aspect, in a ninth possible implementation, the processing module is specifically configured to:

determine the frequency-domain resource scheduling granularity according to the system bandwidth, where the frequency-domain resource scheduling granularity satisfies at least one of the following rules:

when the system bandwidth is less than or equal to 10 RBs, the frequency-domain resource scheduling granularity is NRBRBs; when the system bandwidth is 11 to 26 RBs, the frequency-domain resource scheduling granularity is

NRB⁢⁢or⁢⁢⌊NRB2⌋⁢⁢RBs;
when the system bandwidth is 27 to 63 RBs, the frequency-domain resource scheduling granularity is

⌊NRB2⌋⁢⁢or⁢⁢⌊NRB3⌋⁢⁢or⁢⁢⌊NRB4⌋⁢⁢RBs;
or when the system bandwidth is 64 to 110 RBs, the frequency-domain resource scheduling granularity is

⌊NRB4⌋⁢⁢or⁢⁢⌊NRB5⌋⁢⁢RBs,
where NRBis a quantity of RBs included in the system bandwidth.

With reference to the eighth possible implementation of the second aspect, in a tenth possible implementation, the processing module is specifically configured to determine the frequency-domain resource scheduling granularity according to the available short-TTI data transmission bandwidth, where

the available short-TTI data transmission bandwidth is the bandwidth that can be occupied by the short-TTI data transmission resource; and

the frequency-domain resource scheduling granularity satisfies at least one of the following rules:

when the available short-TTI data transmission bandwidth is less than or equal to 10 RBs, the frequency-domain resource scheduling granularity is NRBRBs; when the available short-TTI data transmission bandwidth is 11 to 26 RBs, the frequency-domain resource scheduling granularity is

NRB⁢⁢or⁢⁢⌊NRB2⌋⁢⁢RBs;
when the available short-TTI data transmission bandwidth is 27 to 63 RBs, the frequency-domain resource scheduling granularity is

⌊NRB2⌋⁢⁢or⁢⁢⌊NRB3⌋⁢⁢or⁢⁢⌊NRB4⌋⁢⁢RBs;
or when the available short-TTI data transmission bandwidth is 64 to 110 RBs, the frequency-domain resource scheduling granularity is

⌊NRB4⌋⁢⁢or⁢⁢⌊NRB5⌋⁢⁢RBs,
where NRBis a quantity of RBs included in the available short-TTI data transmission bandwidth.

With reference to any one of the eighth to the tenth possible implementations of the second aspect, in an eleventh possible implementation, the processing module is specifically configured to:

determine that a size of the frequency-domain transmission resource is the same as a size of the frequency-domain resource scheduling granularity; and

determine that an starting resource block RB of the frequency-domain transmission resource is a reference RB, where

the reference RB is the mthRB following the first RB occupied by the DCI or the mthRB following the last RB occupied by the DCI, and m is an integer greater than or equal to 0.

With reference to the seventh or the eleventh possible implementation of the second aspect, in a twelfth possible implementation,

an information bit that is used to indicate the frequency-domain transmission resource and that is in the DCI is null.

With reference to any one of the eighth to the tenth possible implementations of the second aspect, in a thirteenth possible implementation, the processing module is specifically configured to:

determine that a size of the frequency-domain transmission resource is the same as a size of the frequency-domain resource scheduling granularity; and

determine, according to information that is used to indicate a location of the frequency-domain transmission resource and that is included in the DCI, the location of the frequency-domain transmission resource.

With reference to any one of the eighth to the tenth possible implementations of the second aspect, in a fourteenth possible implementation, the processing module is specifically configured to:

determine that an starting RB of the frequency-domain transmission resource is a reference RB, where the reference RB is the mthRB following the first RB occupied by the DCI or the mthRB following the last RB occupied by the DCI, and m is an integer greater than or equal to 0; and

determine, according to information that is used to indicate a size of a bandwidth occupied by the frequency-domain transmission resource and that is included in the DCI, the size of the bandwidth occupied by the frequency-domain transmission resource.

With reference to any one of the second aspect or the first to the fourteenth possible implementations of the second aspect, in a fifteenth possible implementation,

the transceiver module is further configured to: before the processing module determines the data transmission resource, receive higher layer signaling or physical layer signaling that is sent by the base station, where the signaling indicates to the terminal device that the data transmission resource used to perform the data transmission with the base station is the short-TTI data transmission resource; and

the processing module is further configured to determine, according to the higher layer signaling or the physical layer signaling, that the data transmission resource used to perform the data transmission with the base station is the short-TTI data transmission resource.

With reference to any one of the second aspect or the first to the fifteenth possible implementations of the second aspect, in a sixteenth possible implementation,

the transceiver module is further configured to: before the processing module determines the data transmission resource, receive information that is about the available short-TTI data transmission resource and that is sent by the base station; and

the processing module is further configured to determine the available short-TTI data transmission resource according to the information.

According to a third aspect, an embodiment of the present invention provides a data transmission method, including:

determining, by a base station, a data transmission resource, where the data transmission resource is a short-TTI data transmission resource, and the short-TTI data transmission resource is less than a length of one subframe or is less than 1 ms in time domain:

sending, by the base station, DCI to a terminal device, where the DCI is used to indicate the data transmission resource; and

performing, by the base station, data transmission with the terminal device on the data transmission resource.

With reference to the third aspect, in a first possible implementation, the data transmission resource includes a time-domain transmission resource; and

the determining, by a base station, the data transmission resource includes:

determining, by the base station, a time-domain pattern, and selecting, from multiple time-domain elements included in the determined time-domain pattern, one time-domain element as the time-domain transmission resource; or

determining, by the base station, an starting symbol and a quantity of symbols of the time-domain transmission resource.

With reference to the first possible implementation of the third aspect, in a second possible implementation, the determining, by the base station, the time-domain pattern includes:

determining, by the base station, the time-domain pattern according to a system bandwidth, where a higher system bandwidth indicates a smaller quantity of symbols included in the selected time-domain element included in the time-domain pattern; or

determining, by the base station, the time-domain pattern according to an available short-TTI data transmission bandwidth, where a higher available short-TTI data transmission bandwidth indicates a smaller quantity of symbols included in the selected time-domain element included in the time-domain pattern, and the available short-TTI data transmission bandwidth is a bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to the first or the second possible implementation of the third aspect, in a third possible implementation, in the time-domain pattern:

each subframe includes two time-domain elements, a first time-domain element is located in the first slot, a second time-domain element is located in the second slot, and the time-domain elements do not include a symbol occupied by a legacy PDCCH; or

each subframe includes four time-domain elements; for a normal cyclic prefix CP, a first time-domain element is a set of symbols whose sequence numbers are {#0, #1, #2, #3}, a second time-domain element includes a set of symbols whose sequence numbers are {#4, #5, #6}, a third time-domain element is a set of symbols whose sequence numbers are {#7, #8. #9, #10}, and a fourth time-domain element is a set of symbols whose sequence numbers are {#11, #12, #13}; for an extended CP, every three consecutive symbols form one time-domain element, a first time-domain element is a set of symbols whose sequence numbers are {#0. #1, #2}, a second time-domain element is a set of symbols whose sequence numbers are {#3, #4, #5}, a third time-domain element is a set of symbols whose sequence numbers are {#6. #7, #8}, and a fourth time-domain element is a set of symbols whose sequence numbers are {#9, #10, #11}; and the time-domain elements do not include a symbol occupied for transmitting a PDCCH; or

for a normal CP, each subframe includes seven time-domain elements, and every two consecutive symbols form one time-domain element; for an extended CP, each subframe includes six time-domain elements, and every two consecutive symbols form one time-domain element; and the time-domain elements do not include a symbol occupied by a legacy PDCCH.

With reference to the first possible implementation of the third aspect, in a fourth possible implementation, the determining, by the base station, an starting symbol and a quantity of symbols of the time-domain transmission resource includes:

using, by the base station, a reference symbol as the starting symbol of the time-domain transmission resource, where the reference symbol is the first symbol occupied by the DCI, the last symbol occupied by the DCI, the kthsymbol following the first symbol occupied by the DCI, or the kthsymbol following the last symbol occupied by the DCI, and k is a positive integer; and

determining, by the base station according to a system bandwidth, the quantity of symbols of the time-domain transmission resource, where a higher system bandwidth indicates a smaller quantity of occupied symbols, or

determining, by the base station according to an available short-TTI data transmission bandwidth, the quantity of symbols of the time-domain transmission resource, where a higher available short-TTI data transmission bandwidth indicates a smaller quantity of occupied symbols, and the available short-TTI data transmission bandwidth is a bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the first to the fourth possible implementations of the third aspect, in a fifth possible implementation, an information bit that is used to indicate the time-domain transmission resource and that is in the DCI is null.

With reference to any one of the third aspect or the first to the fifth possible implementations of the third aspect, in a sixth possible implementation, the data transmission resource includes a frequency-domain transmission resource; and

the determining, by a base station, the data transmission resource includes:

determining, by the base station, that the frequency-domain transmission resource is the system bandwidth or the available short-TTI data transmission bandwidth, where the available short-TTI data transmission bandwidth is the bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the third aspect or the first to the fifth possible implementations of the third aspect, in a seventh possible implementation, the data transmission resource includes a frequency-domain transmission resource:

before the determining, by a base station, the data transmission resource, the method further includes:

determining, by the base station, a frequency-domain resource scheduling granularity, where the frequency-domain resource scheduling granularity is a minimum frequency-domain resource allocation unit used when the base station schedules the terminal device to perform the data transmission, and includes at least one resource block RB; and

the determining, by a base station, the data transmission resource includes:

determining, by the base station, the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity.

With reference to the seventh possible implementation of the third aspect, in an eighth possible implementation, the determining, by the base station, the frequency-domain resource scheduling granularity includes:

determining, by the base station, the frequency-domain resource scheduling granularity according to the system bandwidth, where

the frequency-domain resource scheduling granularity satisfies at least one of the following rules:

when the system bandwidth is less than or equal to 10 RBs, the frequency-domain resource scheduling granularity is NRBRBs; when the system bandwidth is 11 to 26 RBs, the frequency-domain resource scheduling granularity is

NRB⁢⁢or⁢⁢⌊NRB2⌋⁢⁢RBs;
when the system bandwidth is 27 to 63 RBs, the frequency-domain resource scheduling granularity is

⌊NRB2⌋⁢⁢or⁢⁢⌊NRB3⌋⁢⁢or⁢⁢⌊NRB4⌋⁢⁢RBs;
or when the system bandwidth is 64 to 110 RBs, the frequency-domain resource scheduling granularity is

⌊NRB4⌋⁢⁢or⁢⁢⌊NRB5⌋⁢⁢RBs,
where NRBis a quantity of RBs included in the system bandwidth.

With reference to the seventh possible implementation of the third aspect, in a ninth possible implementation, the determining, by the base station, a frequency-domain resource scheduling granularity includes:

determining, by the base station, the frequency-domain resource scheduling granularity according to the available short-TTI data transmission bandwidth, where the available short-TTI data transmission bandwidth is the bandwidth that can be occupied by the short-TTI data transmission resource, where

the frequency-domain resource scheduling granularity satisfies at least one of the following rules:

when the available short-TTI data transmission bandwidth is less than or equal to 10 RBs, the frequency-domain resource scheduling granularity is NRBRBs; when the available short-TTI data transmission bandwidth is 11 to 26 RBs, the frequency-domain resource scheduling granularity is

NRB⁢⁢or⁢⁢⌊NRB2⌋⁢⁢RBs;
when the available short-TTI data transmission bandwidth is 27 to 63 RBs, the frequency-domain resource scheduling granularity is

⌊NRB2⌋⁢⁢or⁢⁢⌊NRB3⌋⁢⁢or⁢⁢⌊NRB4⌋⁢⁢RBs;
or when the available short-TTI data transmission bandwidth is 64 to 110 RBs, the frequency-domain resource scheduling granularity is

⌊NRB4⌋⁢⁢or⁢⁢⌊NRB5⌋⁢⁢RBs,
where NRBis a quantity of RBs included in the available short-TTI data transmission bandwidth.

With reference to any one of the seventh to the ninth possible implementations of the third aspect, in a tenth possible implementation, the determining, by the base station, the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity includes: using, by the base station, a size of the frequency-domain resource scheduling granularity as a size of the frequency-domain transmission resource; and

using, by the base station, a reference RB as an starting resource block RB of the frequency-domain transmission resource, where

the reference RB is the mthRB following the first RB occupied by the DCI or the mthRB following the last RB occupied by the DCI, and m is an integer greater than or equal to 0.

With reference to the sixth or the tenth possible implementation of the third aspect, in an eleventh possible implementation, an information bit that is used to indicate the frequency-domain transmission resource and that is in the DCI is null.

With reference to any one of the seventh to the ninth possible implementations of the third aspect, in a twelfth possible implementation,

the determining, by the base station, the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity includes: using, by the base station, a size of the frequency-domain resource scheduling granularity as a size of the frequency-domain transmission resource, where

the DCI includes information used to indicate a location of the frequency-domain transmission resource.

With reference to any one of the seventh to the ninth possible implementations of the third aspect, in a thirteenth possible implementation, the determining, by the base station, the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity includes:

using, by the base station, a reference RB as an starting RB of the frequency-domain transmission resource, where

the reference RB is the mthRB following the first RB occupied by the DCI or the mthRB following the last RB occupied by the DCI, and m is an integer greater than or equal to 0; and

the DCI includes information used to indicate a size of a bandwidth occupied by the frequency-domain transmission resource.

With reference to any one of the third aspect or the first to the thirteenth possible implementations of the third aspect, in a fourteenth possible implementation, before the determining, by a base station, the data transmission resource, the method further includes:

when at least one of the following conditions is satisfied, determining, by the base station, that the data transmission resource used to perform the data transmission with the terminal device is the short-TTI data transmission resource:

a latency requirement of a service currently used by the terminal device is less than a specified latency threshold; or

the system bandwidth is greater than a specified bandwidth threshold.

With reference to the fourteenth possible implementation of the third aspect, in a fifteenth possible implementation, after the determining, by the base station, that the data transmission resource used to perform the data transmission with the terminal device is the short-TTI data transmission resource, and before the determining the data transmission resource, the method further includes:

sending, by the base station, higher layer signaling or physical layer signaling to the terminal device, to indicate to the terminal device that the data transmission resource used to perform the data transmission between the base station and the terminal device is the short-TTI data transmission resource.

With reference to any one of the third aspect or the first to the fifteenth possible implementations of the third aspect, in a sixteenth possible implementation,

before the determining, by a base station, the data transmission resource, the method further includes:

determining, by the base station, the available short-TTI data transmission resource; and

sending, by the base station to the terminal device, information indicating the available short-TTI data transmission resource.

According to a fourth aspect, an embodiment of the present invention provides a data transmission method, including:

receiving, by a terminal device, DCI sent by a base station, where the DCI is used to indicate a data transmission resource;

determining, by the terminal device, the data transmission resource according to the DCI, where the data transmission resource is a short-TTI data transmission resource, and the short-TTI data transmission resource is less than a length of one subframe or is less than 1 ms in time domain; and

performing, by the terminal device, data transmission with the base station on the data transmission resource.

With reference to the fourth aspect, in a first possible implementation, the data transmission resource includes a time-domain transmission resource; and

the determining, by the terminal device, the data transmission resource according to the DCI includes:

determining, by the terminal device, a time-domain pattern, and determining, according to the DCI and in multiple time-domain elements included in the determined time-domain pattern, one time-domain element as the time-domain transmission resource; or

determining, by the terminal device according to the DCI, an starting symbol and a quantity of symbols of the time-domain transmission resource.

With reference to the first possible implementation of the fourth aspect, in a second possible implementation, the determining, by the terminal device according to the DCI and in multiple time-domain elements included in the determined time-domain pattern, one time-domain element as the time-domain transmission resource includes:

if the data transmission is downlink data transmission, determining, by the terminal device, that a time-domain element occupied by the DCI is the time-domain transmission resource; or

if the data transmission is uplink data transmission, determining, by the terminal device, that a time-domain element in which the kthsymbol following the first symbol occupied by the DCI or the kthsymbol following the last symbol occupied by the DCI is located is the time-domain transmission resource.

With reference to the first or the second possible implementation of the fourth aspect, in a third possible implementation, the determining, by the terminal device, the time-domain pattern includes:

determining, by the terminal device, the time-domain pattern according to a system bandwidth, where a higher system bandwidth indicates a smaller quantity of symbols included in the time-domain element included in the determined time-domain pattern; or

determining, by the terminal device, the time-domain pattern according to an available short-TTI data transmission bandwidth, where a higher available short-TTI data transmission bandwidth indicates a smaller quantity of symbols included in the time-domain element included in the determined time-domain pattern, and the available short-TTI data transmission bandwidth is a bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the first to the third possible implementations of the fourth aspect, in a fourth possible implementation, in the time-domain pattern:

each subframe includes two time-domain elements, a first time-domain element is located in the first slot, a second time-domain element is located in the second slot, and the time-domain elements do not include a symbol occupied by a legacy PDCCH; or

each subframe includes four time-domain elements; for a normal cyclic prefix CP, a first time-domain element includes a set of symbols whose sequence numbers are {#0, #1. #2, #3}, a second time-domain element includes a set of symbols whose sequence numbers are {#4. #5, #6}, a third time-domain element includes a set of symbols whose sequence numbers are {#7, #8, #9, #10}, and a fourth time-domain element includes a set of symbols whose sequence numbers are {#11, #12, #13}; for an extended CP, every three consecutive symbols form one time-domain element, a first time-domain element includes a set of symbols whose sequence numbers are {#0, #1, #2}, a second time-domain element includes a set of symbols whose sequence numbers are {#3, #4, #5}, a third time-domain element includes a set of symbols whose sequence numbers are {#6, #7, #8}, and a fourth time-domain element includes a set of symbols whose sequence numbers are {#9, #10, #11}; and the time-domain elements do not include a symbol occupied for transmitting a PDCCH; or

for a normal CP, each subframe includes seven time-domain elements, and every two consecutive symbols form one time-domain element; for an extended CP, each subframe includes six time-domain elements, and every two consecutive symbols form one time-domain element; and the time-domain elements do not include a symbol occupied by a legacy PDCCH.

With reference to the first possible implementation of the fourth aspect, in a fifth possible implementation, the determining, by the terminal device according to the DCI, an starting symbol and a quantity of symbols of the time-domain transmission resource includes:

determining, by the terminal device, that the starting symbol of the time-domain transmission resource is a reference symbol, where the reference symbol is the first symbol occupied by the DCI, the last symbol occupied by the DCI, the kthsymbol following the first symbol occupied by the DCI, or the kthsymbol following the last symbol occupied by the DCI, and k is a positive integer; and

determining, by the terminal device according to a system bandwidth, the quantity of symbols of the time-domain transmission resource, where a higher system bandwidth indicates a smaller quantity of occupied symbols; or determining, by the terminal device according to an available short-TTI data transmission bandwidth, the quantity of symbols of the time-domain transmission resource, where a higher available short-TTI data transmission bandwidth indicates a smaller quantity of occupied symbols, and the available short-TTI data transmission bandwidth is a bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the first to the fifth possible implementations of the fourth aspect, in a sixth possible implementation, an information bit that is used to indicate the time-domain transmission resource and that is in the DCI is null.

With reference to any one of the fourth aspect or the first to the sixth possible implementations of the fourth aspect, in a seventh possible implementation, the data transmission resource includes a frequency-domain transmission resource; and

the determining, by the terminal device, the data transmission resource includes:

determining, by the terminal device, that the frequency-domain transmission resource is the system bandwidth or the available short-TTI data transmission bandwidth, where

the available short-TTI data transmission bandwidth is the bandwidth that can be occupied by the short-TTI data transmission resource.

With reference to any one of the fourth aspect or the first to the sixth possible implementations of the fourth aspect, in an eighth possible implementation, the data transmission resource includes a frequency-domain transmission resource;

before the determining, by the terminal device, the data transmission resource, the method further includes:

determining, by the terminal device, a frequency-domain resource scheduling granularity, where the frequency-domain resource scheduling granularity is a minimum frequency-domain resource allocation unit used when the base station schedules the terminal device to perform the data transmission, and includes at least one resource block RB; and

the determining, by the terminal device, the data transmission resource includes:

determining, by the terminal device, the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity and the DCI.

With reference to the eighth possible implementation of the fourth aspect, in a ninth possible implementation, the determining, by the terminal device, the frequency-domain resource scheduling granularity includes:

determining, by the terminal device, the frequency-domain resource scheduling granularity according to the system bandwidth, where

the frequency-domain resource scheduling granularity satisfies at least one of the following rules:

when the system bandwidth is less than or equal to 10 RBs, the frequency-domain resource scheduling granularity is NRBRBs; when the system bandwidth is 11 to 26 RBs, the frequency-domain resource scheduling granularity is

NRB⁢⁢or⁢⁢⌊NRB2⌋⁢⁢RBs;
when the system bandwidth is 27 to 63 RBs, the frequency-domain resource scheduling granularity is

⌊NRB2⌋⁢⁢or⁢⁢⌊NRB3⌋⁢⁢or⁢⁢⌊NRB4⌋⁢⁢RBs;
or when the system bandwidth is 64 to 110 RBs, the frequency-domain resource scheduling granularity is

⌊NRB4⌋⁢⁢or⁢⁢⌊NRB5⌋⁢⁢RBs,
where NRBis a quantity of RBs included in the system bandwidth.

With reference to the eighth possible implementation of the fourth aspect, in a tenth possible implementation, the determining, by the terminal device, the frequency-domain resource scheduling granularity includes:

determining, by the terminal device, the frequency-domain resource scheduling granularity according to the available short-TTI data transmission bandwidth, where

the available short-TTI data transmission bandwidth is the bandwidth that can be occupied by the short-TTI data transmission resource; and

the frequency-domain resource scheduling granularity satisfies at least one of the following rules:

when the available short-TTI data transmission bandwidth is less than or equal to 10 RBs, the frequency-domain resource scheduling granularity is NRBRBs; when the available short-TTI data transmission bandwidth is 11 to 26 RBs, the frequency-domain resource scheduling granularity is

NRB⁢⁢or⁢⁢⌊NRB2⌋⁢⁢RBs;
when the available short-TTI data transmission bandwidth is 27 to 63 RBs, the frequency-domain resource scheduling granularity is or

⌊NRB2⌋⁢⁢or⁢⁢⌊NRB3⌋⁢⁢or⁢⁢⌊NRB4⌋⁢⁢RBs;
or when the available short-TTI data transmission bandwidth is 64 to 110 RBs, the frequency-domain resource scheduling granularity is

⌊NRB4⌋⁢⁢or⁢⁢⌊NRB5⌋⁢⁢RBs,
where is a quantity of RBs included in the available short-TTI data transmission bandwidth.

With reference to any one of the eighth to the tenth possible implementations of the fourth aspect, in an eleventh possible implementation, the determining, by the terminal device, the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity and the DCI includes:

determining, by the terminal device, that a size of the frequency-domain transmission resource is the same as a size of the frequency-domain resource scheduling granularity; and

determining, by the terminal device, that an starting resource block RB of the frequency-domain transmission resource is a reference RB, where

the reference RB is the mthRB following the first RB occupied by the DCI or the mthRB following the last RB occupied by the DCI, and m is an integer greater than or equal to 0.

With reference to the seventh or the eleventh possible implementation of the fourth aspect, in a twelfth possible implementation,

an information bit that is used to indicate the frequency-domain transmission resource and that is in the DCI is null.

With reference to any one of the eighth to the tenth possible implementations of the fourth aspect, in a thirteenth possible implementation, the determining, by the terminal device, the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity and the DCI includes:

determining, by the terminal device, that a size of the frequency-domain transmission resource is the same as a size of the frequency-domain resource scheduling granularity; and

determining, by the terminal device according to information that is used to indicate a location of the frequency-domain transmission resource and that is included in the DCI, the location of the frequency-domain transmission resource.

With reference to any one of the eighth to the tenth possible implementations of the fourth aspect, in a fourteenth possible implementation, the determining, by the terminal device, the frequency-domain transmission resource according to the frequency-domain resource scheduling granularity and the DCI includes:

determining, by the terminal device, that an starting RB of the frequency-domain transmission resource is a reference RB, where the reference RB is the mthRB following the first RB occupied by the DCI or the mthRB following the last RB occupied by the DCI, and m is an integer greater than or equal to 0; and

determining, by the terminal device according to information that is used to indicate a size of a bandwidth occupied by the frequency-domain transmission resource and that is included in the DCI, the size of the bandwidth occupied by the frequency-domain transmission resource.

With reference to any one of the fourth aspect or the first to the fourteenth possible implementations of the fourth aspect, in a fifteenth possible implementation.

before the determining, by the terminal device, the data transmission resource, the method further includes:

receiving, by the terminal device, higher layer signaling or physical layer signaling that is sent by the base station, where the signaling indicates to the terminal device that the data transmission resource used to perform the data transmission with the base station is the short-TTI data transmission resource; and

determining, by the terminal device according to the higher layer signaling or the physical layer signaling, that the data transmission resource used to perform the data transmission with the base station is the short-TTI data transmission resource.

With reference to any one of the fourth aspect or the first to the fifteenth possible implementations of the fourth aspect, in a sixteenth possible implementation,

before the determining, by the terminal device, the data transmission resource, the method further includes:

receiving, by the terminal device, information that is about the available short-TTI data transmission resource and that is sent by the base station, and determining the available short-TTI data transmission resource according to the information.

According to a fifth aspect, an embodiment of the present invention provides a wireless communications system, including a base station and a terminal device, where

the base station is configured to: determine a data transmission resource, where the data transmission resource is a short-TTI data transmission resource, and the short-TTI data transmission resource is less than a length of one subframe or is less than 1 ms in time domain; send DCI to the terminal device, where the DCI is used to indicate the data transmission resource; and perform data transmission with the terminal device on the data transmission resource; and

the terminal device is configured to: receive the DCI sent by the base station; determine the data transmission resource according to the DCI; and perform the data transmission with the base station on the data transmission resource.

In the embodiments of the present invention, because the data transmission resource is the short-TTI data transmission resource, a transmission time interval is shortened, a quantity of times of scheduling per unit time can be increased for one terminal device, and a data transmission latency can be effectively reduced.

