Patent Description:
Embodiments of the present invention relate to the field of communications technologies, and in particular, to a downlink transmission method and an apparatus.

As mobile terminals increase and user service types are diversified, mobile data traffic is going to explode, and a total quantity of devices that are connected to mobile communications network is expected to hit <NUM> billion in the world in the future. It is predicted that a quantity of mobile terminals (excluding devices of the Internet of Things) will exceed <NUM> billion by <NUM> in the world and exceed <NUM> billion in China. A quantity of devices that are connected to the Internet of Things in the world will also increase rapidly. The quantity of devices that are connected to the Internet of Things will be nearly <NUM> billion in the world and will exceed <NUM> billion in China. Varied service types have greatly different network requirements, for example, an Internet of vehicles service requires an end-to-end latency of <NUM>. In a multi-connection scenario of the Internet of Things, transmission data volume of a single sensor is very low. However, there is a very high requirement on an overall quantity of connections. For another example, three dimensional (three dimensional, 3D) holographic imaging requires a bandwidth of x Gbps (<NUM> megabytes per second). General requirements include reliable and latency-insensitive transmission; or low-latency and high-reliable transmission.

A service with reliable and latency-insensitive transmission can be relatively easily processed. However, for a type of service with low-latency and high-reliable transmission, for example, a vehicle-to-vehicle (Vehicle to Vehicle, V2V) service, a transmission latency and reliability are required. If transmission is unreliable, retransmission is caused, and this brings a very high transmission latency, and therefore, a requirement cannot be met. Because there are a large quantity of connections, a future radio communications system is greatly different from a current communications system. The large quantity of connections means that more resources need to be consumed for access of the terminal device and that more resources need to be consumed for transmitting scheduling signaling related to data transmission of the terminal device.

To resolve the foregoing problem, a grant-free transmission (grant-free) solution is proposed in the prior art to reduce transmission latency. A specific implementation solution is: A network device pre-allocates a plurality of transmission resources for a terminal device, and notifies the terminal device of the plurality of transmission resources. When needing to transmit uplink data, the terminal device selects at least one transmission resource from the plurality of transmission resources that are pre-allocated by the network device, and the terminal device does not need to request an uplink transmission resource by using signaling each time, thereby reducing signaling overheads and reducing transmission latency.

In grant-free transmission, there are a plurality of reliable uplink transmission solutions, including duplicate (duplicate) transmission in time domain, frequency domain, and space domain. The main purpose is to ensure reliable transmission over an air interface. However, for grant-free downlink transmission, when downlink data arrives, a user is generally notified through paging (paging), and then the user receives data at a specified location. However, for connected mode transmission, downlink data is mainly scheduled by using a physical downlink control channel (Physical Downlink Control Channel, PDCCH). However, currently, scheduling is generally performed once, and retransmission is performed if an error occurs. Therefore, for ultra-reliable and low-latency communications (Ultra-reliable and Low-latency Communications, URLLC) transmission, a latency requirement cannot be met.

<CIT> discloses a data transmission method. The method includes: generating a configuration message, where the configuration message is used to configure, for user equipment UE, a function of receiving downlink bundled data, and the downlink bundled data is downlink data that is repeatedly transmitted at least twice; and sending the configuration message to the UE and sending the downlink bundled data to the UE. According to the data transmission method, downlink data is sent to user equipment in a downlink bundling manner, thereby shortening a delay of the downlink data transmission. If the downlink data is PDCCH control signaling, timeliness of an operation indicated by the PDCCH control signaling may also be improved. Further, a function of receiving downlink bundled data is flexibly configured and enabled for the UE, thereby preventing the UE from receiving, in all scenarios, the downlink data in a manner of receiving the downlink bundled data. Further, <CIT> (<NUM>-<NUM>-<NUM>) discloses transmitting resource allocation information in a low latency system.

Specific embodiments are defined by the dependent claims.

Embodiments of the present invention provide a downlink transmission method and an apparatus, so as to resolve a problem that a downlink transmission manner in the prior art cannot meet a latency requirement of ultra-reliable and low-latency communications.

To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. The protection scope of the present invention is defined by the appended claims.

Embodiments of the present invention provide a downlink transmission method. When downlink data is transmitted, a plurality of transmission resources are specified to transmit data blocks at the same time, and the plurality of transmission resources may be in a relationship of time division, frequency division, or space division. The plurality of transmission resources are indicated to a terminal device by using a signaling indication; the terminal device receives the data blocks on the specified plurality of transmission resources based on the signaling indication; and after receiving the data blocks, the terminal device may combine signal gains, thereby improving transmission bit error performance. The following further describes the solutions provided in the embodiments of the present invention in detail with reference to specific implementations.

As shown in <FIG>, an embodiment of the present invention provides a downlink transmission method, and the method specifically includes the following steps.

Step <NUM>: A network side device sends a signaling indication to a terminal device (User Equipment, UE), where the signaling indication carries allocation information, and the allocation information is used to indicate a plurality of downlink transmission resources used to transmit data blocks.

In this embodiment, the plurality of downlink transmission resources are corresponding to a plurality of resource blocks that are formed through time division, frequency division, or space division. The data blocks that are transmitted on the plurality of resource blocks may be completely consistent, or may be different redundancy versions that are obtained after channel coding is performed on a same data block, and version numbers of these different versions may be notified in real time or may be predetermined. The different redundancy versions do not need to include completely same content; on the contrary, the different redundancy versions will be a set of different coded bits, and each set of coded bits represents information bits of a same data set. Because a redundancy version of the same data block may include an additional check bit that is not included in another redundancy version, in this embodiment, when the plurality of resource blocks are used to transmit different redundancy versions of the same data block, sizes of resource blocks in the plurality of resource blocks may be different. Correspondingly, different modulation and coding schemes (English full name: Modulation and Coding Scheme, MCS) are used in the plurality of transmission resource blocks.

Optionally, based on an MCS corresponding to the resource block, the signaling indication may further include one or more MCSs. In this embodiment, the UE and the network side device may predefine and number several dedicated MCSs of URLLC transmission by using a protocol. In the dedicated MCSs of the URLLC, a manner with a lower bit rate and lower-order modulation is used to ensure more reliable transmission.

Step <NUM>: The terminal device UE receives the signaling indication that is sent by the network side device, and receives the data blocks on the plurality of downlink transmission resources based on the allocation information.

In this embodiment of the present invention, the network side device determines, based on whether the terminal device supports the URLLC transmission, whether to send the signaling indication to the UE. A manner in which the network side device interacts with the terminal to determine whether the terminal supports the URLLC may be shown in <FIG>.

Step <NUM>: The UE sends transmission capability information of the UE to the network side device, where the transmission capability information is used to indicate whether the UE supports URLLC transmission.

When sending the transmission capability information, the UE may further send service information of the UE, channel state information of the UE, mobility of the UE, and the like.

Step <NUM>: The network side device obtains transmission capability information of the UE, and the network side device determines, based on the transmission capability information, whether to send the signaling indication to the UE.

The network side device determines, based on capability of the UE, a current service, and a current status of the UE, whether to use a downlink transmission manner of the URLLC, selects the one or more MCSs from the dedicated MCSs of URLLC, performs MCS reconfiguration on the UE, and sends a number of the MCS to the UE, so as to transmit the current service by using the MCS.

In this embodiment, the UE and the terminal device may exchange the transmission capability information in the following manner, which may be specifically:.

Optionally, allocation of the downlink transmission resources includes a time-frequency location or time-frequency locations of one or more scheduled resource blocks that are invoked, and allocation of the resource blocks may also be determined by using a correspondence between the resource blocks. For example, a relative time-frequency location between the resource blocks is specified, that is, a location error between the resource blocks in time domain and frequency domain, and a quantity of the scheduled resource blocks, and the resource location error and the quantity of resource blocks may be preset, for example, the RRC may be used to perform preconfiguration, and the network device and the UE maintain the configuration information consistent at the same time; or the configuration information may be notified to a user in real time through dynamic scheduling, or may be defined by default by using a protocol, or may be determined when the UE accesses the network device. Specifically, the signaling indication may be carried by using the following downlink signaling: a PDCCH used to carry scheduling information and other downlink control information (a transmission format, resource allocation, uplink scheduling permission, power control, uplink retransmission information, and the like), a paging signal, or the RRC signaling used to process third layer information of a control plane between the UE and the eNodeB. Here is merely an example. The method provided in this embodiment of the present invention is not limited to carrying the signaling indication only by using the foregoing signals.

Manner <NUM>: If the resource block is configured by using the PDCCH, a specific scheduling solution may include the following cases:.

Case <NUM>: The allocation information that is sent by the PDCCH includes all information about determining the downlink transmission resource. A specific implementation may be:.

Case <NUM>: The allocation information includes a part of the information about determining the downlink transmission resource. An accurate location of the downlink transmission resource can be determined only by combining the allocation information and preset information. A manner of presetting the information may be: The terminal device and the network side device predefine the information by using a protocol; or the accurate location of the downlink transmission resource is determined when the terminal device accesses the network side device. The following further describes specific implementation in detail by using the protocol to predefine the formation, including:.

(<NUM>) The protocol predefines location errors of a plurality of resources and the quantity of resource blocks, and numbers the plurality of various configurations. For example, a table shown in Table <NUM> is defined:.

The allocation information includes the numbers of the configurations and the time-frequency location of the reference resource block in the resource blocks corresponding to the plurality of downlink transmission resources.

With reference to the specific value shown in Table <NUM>, Manner <NUM> in Table <NUM> is selected for description:
The downlink transmission resource is corresponding to three resource blocks. When a location of a reference resource block is determined, locations of the other two resource blocks in the three resource blocks are shown in <FIG>: The second resource block is offset by one resource block unit based on the time domain and frequency domain of the reference resource block, and the third resource block is offset by one resource block unit based on the time domain and frequency domain of the second resource block. Certainly, a resource configuration parameter table in another manner may also be defined, and is not limited to the implementation of Table <NUM>.

(<NUM>) The allocation information includes the time-frequency location of the reference resource block, and the protocol predefines the location error of the resource block and the quantity of resource blocks (that is, configures a fixed location error of the resource and the quantity of resource blocks).

(<NUM>) The allocation information includes the time-frequency location of the reference resource block and the quantity of resource blocks, and the protocol predefines the location error of the resource.

(<NUM>) The allocation information includes the time-frequency location of the reference resource block and the location error of the resource block, and the quantity of the resource blocks is predefined.

(<NUM>) The protocol predefines a number of each resource block and a number of each resource block group. For example, there are <NUM> available resource blocks as shown in <FIG> in a system bandwidth, and numbers of the <NUM> available resource blocks are <NUM>-<NUM>, a number of a {<NUM>, <NUM>} resource block group is <NUM>, a number of a {<NUM>, <NUM>} resource block group is <NUM>,. , a number of a {<NUM>, <NUM>, <NUM>}resource block group is n (n is a positive integer); and the corresponding allocation information includes the numbers of the resource block groups.

Manner <NUM>: A part of resource configuration information may also be preconfigured by the RRC signaling, which is described in detail as follows:.

When the terminal device is in an idle (idle) state, allocation information of the URLLC may be sent to the terminal device by using the paging.

In an existing downlink transmitted subframe, a downlink control channel configured in LTE generally occupies first three OFDM symbols in a subframe, and occupies the entire system bandwidth; and remaining OFDM symbols of the subframe are occupied by a physical downlink shared channel (Physical Downlink Shared Channel, PDSCH) that carries user data and a reference signal, and the PDSCH carries the downlink data transmission. A plurality of resource blocks used to transmit data may be in a relationship of frequency division in (a) in <FIG> on the PDSCH, or may be in a relationship of time division in (b) in <FIG>, or may be time-frequency resource blocks in (c) in <FIG>, or may be a plurality of resource blocks that are scheduled in different subframes in (d) in <FIG> or in (e) in <FIG>. In this embodiment of the present invention, scheduling signaling may be indicated in a first subframe, and no scheduling signaling needs to be indicated in a subsequent subframe. Another plurality of transmission resources may also be in a relationship of space division, in other words, different transmission antenna ports are used. The plurality of transmission resources may be indicated to the terminal by using signaling; and the terminal receives data on the specified plurality of resources based on the signaling indication and combines signal gains, thereby improving transmission bit error performance.

As shown in <FIG>, an embodiment of the present invention provides a network side device, including:.

Optionally, the processor <NUM> is further configured to: obtain transmission capability information of the UE; and determine, based on the transmission capability information, whether to send the signaling indication to the UE, where the transmission capability information is used to indicate whether the UE supports ultra-reliable and low-latency communications URLLC transmission.

Optionally, the processor <NUM> is specifically configured to: obtain the transmission capability information of the UE from a message that is sent by the UE in a random access process; or obtain the transmission capability information of the UE from RRC signaling.

Optionally, the processor <NUM> is configured to use a time division resource, a frequency division resource, or a space division resource as the downlink transmission resource.

Optionally, the transceiver <NUM> is configured to send the signaling indication to the UE by using one or a combination of a plurality of the following downlink signaling: a physical downlink control channel PDCCH, paging signaling, or the RRC signaling.

Optionally, the processor <NUM> is configured to add a time-frequency interval between the plurality of downlink transmission resources, a quantity of resource blocks corresponding to the plurality of downlink transmission resources, and a time-frequency location of a reference resource block in the resource blocks to the signaling indication as the allocation information.

Optionally, the processor <NUM> is configured to add time-frequency locations of the plurality of downlink transmission resources to the signaling indication as the allocation information.

Optionally, the processor <NUM> is configured to add the time-frequency location of the reference resource block in the resource blocks corresponding to the plurality of downlink transmission resources to the signaling indication as the allocation information; and the corresponding UE determines the downlink transmission resource based on the time-frequency location of the reference resource block, the preconfigured time-frequency interval between the downlink transmission resources, and the quantity of resource blocks.

Optionally, the processor <NUM> is further configured to: predefine, with the UE, the time-frequency interval between the downlink transmission resources and the quantity of resource blocks by using a protocol; or determine the time-frequency interval between the downlink transmission resources and the quantity of resource blocks when the terminal device accesses the network side device.

In this embodiment, the plurality of downlink transmission resources are corresponding to a plurality of resource blocks that are formed through time division, frequency division, or space division. The data blocks that are transmitted on the plurality of resource blocks may be completely consistent; or may be different redundancy versions after channel coding is performed on a same data block, and version numbers of these different versions may be notified in real time or may be predetermined. The different redundancy versions do not need to include completely same content; on the contrary, the different redundancy versions will be a set of different coded bits, and each set of coded bits represents information bits of a same set. Because a redundancy version of the same data block may include an additional check bit that is not included in another redundancy version, the transceiver <NUM> is further configured to use the plurality of resource blocks to send different redundancy versions of the same data block to the UE, where sizes of the plurality of resource blocks may be different, and MCSs corresponding to the plurality of resource blocks are different.

As shown in <FIG>, an embodiment of the present invention further provides a terminal device, including:.

Optionally, the terminal device further includes:
a transmitter, configured to send transmission capability information of the UE to the network side device, so that the network side device determines, based on the transmission capability information, whether to send the signaling indication to the UE, where the transmission capability information is used to indicate whether the UE supports ultra-reliable and low-latency communications URLLC transmission.

Optionally, the transmitter is specifically configured to: carry the transmission capability information in a message that is sent in a random access process; or carry the transmission capability information in RRC signaling.

Optionally, the receiver <NUM> receives the data blocks on the plurality of downlink transmission resources that include a time division resource, a frequency division resource, or a space division resource.

Optionally, the receiver <NUM> is specifically configured to receive the signaling indication from the following downlink signaling: a physical downlink control channel PDCCH, paging signaling, or the RRC signaling.

Optionally, the processor <NUM> is specifically configured to determine the plurality of downlink transmission resources based on a time-frequency interval between the plurality of downlink transmission resources, a quantity of resource blocks corresponding to the plurality of downlink transmission resources, and a time-frequency location of a reference resource block in the resource blocks that are in the allocation information.

Optionally, the processor <NUM> is specifically configured to determine the plurality of downlink transmission resources based on time-frequency locations of the plurality of downlink transmission resources in the allocation information.

Optionally, the processor <NUM> is specifically configured to determine the plurality of downlink transmission resources based on the time-frequency location of the reference resource block in the resource blocks corresponding to the plurality of downlink transmission resource, the preconfigured time-frequency interval between the downlink transmission resources, and the quantity of resource blocks that are in the allocation information.

Optionally, the processor <NUM> is further configured to: predefine, with the network side device, the time-frequency interval between the downlink transmission resources and the quantity of resource blocks by using a protocol; or determine the time-frequency interval between the downlink transmission resources and the quantity of resource blocks when the terminal device connects to the network side device.

Optionally, the receiver <NUM> is further configured to receive, in the plurality of resource blocks, different redundancy versions that are sent by the network side device and that is obtained after channel coding is performed on a same data block, and version numbers of these different versions may be notified in real time, or may be predetermined. Sizes of the plurality of resource blocks may be different, and MCSs corresponding to the plurality of resource blocks are different.

Technical solutions provided in the foregoing embodiments of this application include at least the following technical effects or advantages:
According to the downlink transmission method and an apparatus provided in the embodiments of the present invention, when downlink data is transmitted, a plurality of transmission resources are specified to transmit the data blocks at the same time, and the plurality of transmission resources may be in a relationship of time division, frequency division, or space division. The plurality of transmission resources are indicated to the terminal device by using the signaling indication; the terminal device receives the data blocks on the specified plurality of transmission resources based on the signaling indication; and after receiving the data blocks, the terminal device may combine signal gains, thereby improving transmission bit error performance.

In addition, this application may use a form of a computer program product that is implemented on one or more computer-usable storage media (including but not limited to a disk memory, a CD-ROM, an optical memory, and the like) that include computer usable program code.

This application is described with reference to the flowcharts and/or block diagrams of the method, the device (system), and the computer program product according to the embodiments of the present invention. It should be understood that computer program instructions may be used to implement each process and/or each block in the flowcharts and/or the block diagrams and a combination of a process and/or a block in the flowcharts and/or the block diagrams. These computer program instructions may be provided for a general-purpose computer, a dedicated computer, an embedded processor, or a processor of any other programmable data processing device to generate a machine, so that the instructions executed by a computer or a processor of any other programmable data processing device generate an apparatus for implementing a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

Specifically, a computer program instruction corresponding to the downlink transmission method in the embodiments of the present invention may be stored in a storage medium such as an optical disk, a hard disk, or a USB flash drive. When a computer program instruction corresponding to an information processing method in the storage medium is read or executed by an electronic device, the following step is performed:
The network side device sends the signaling indication to the terminal device UE, so that the UE receives data on the specified plurality of downlink transmission resources based on the signaling indication, where the signaling indication carries the allocation information, and the allocation information is used to indicate the plurality of downlink transmission resources used to transmit the data blocks.

Although some preferred embodiments of this application have been described, a person skilled in the art can make changes and modifications to these embodiments once they learn the basic inventive concept. Therefore, the following claims are intended to be construed as to cover the preferred embodiments and all changes and modifications falling within the scope of this application.

Claim 1:
A downlink transmission method, comprising:
sending (<NUM>), by a network side device, a signaling indication to a terminal device UE, wherein the signaling indication carries allocation information, and the allocation information is used to indicate a plurality of downlink transmission resources used to transmit data blocks,
wherein the allocation information comprises a time-frequency interval between the plurality of downlink transmission resources, a quantity of resource blocks corresponding to the plurality of downlink transmission resources, and a time-frequency location of a reference resource block in the resource blocks or the allocation information comprises
the time-frequency location of the reference resource block in the resource blocks corresponding to the plurality of downlink transmission resources,
characterized in that code modulation schemes of resource blocks in a plurality of resource blocks are different.