Patent Description:
As a long term evolution-advanced (Long Term Evolution-Advanced, LTE-A) requirement is proposed, people pay increasing attention to cell average spectral efficiency and cell edge spectral efficiency. In both an upstream and a downstream of an LTE-A system, there are frequency division systems that use orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) as a basic multiple access multiplexing mode. There is almost no interference problem inside a cell because of complete orthogonal frequency division, but interference processing at an edge of the cell is relatively difficult.

To improve cell edge spectral efficiency, a non-coherent joint transmission (Non Coherent Joint Transmission, NCJT) transmission mode is proposed. NCJT means that a plurality of transmission nodes serve one terminal device at a same time, that is, the terminal device may receive data from the plurality of transmission nodes at the same time. Transmission between two transmission points (Transmission Point, TP) is used as an example. In a schematic diagram of coordinated multipoint transmission/reception shown in <FIG>, a first code word (Code Word <NUM>, CW <NUM>), or referred to as a transport block, is transmitted to a terminal device through a TP <NUM>, and a second code word CW <NUM> is transmitted to the terminal device through a TP <NUM>. Since strict synchronization among a plurality of transmission nodes is not required, and user experience can be improved through joint transmission performed by the plurality of transmission nodes, this transmission technology as a main transmission mode of further enhancements to coordinated multipoint operation (Further Enhancements to Coordinated Multi-Point Operation, Fe-CoMP) has drawn extensive attention and has been widely discussed.

However, in prior-art LTE and LTE-A technologies, one terminal device receives only one or more code words from one transmission node at a same time.

Therefore, a problem that a terminal device cannot correctly demodulate data in a multi-codeword transmission scenario needs to be resolved urgently.

In <NPL>, the contribution has studied the specification impacts of the NC-JT, and made the following observation on the specification impacts of the NC-JT. For <NUM>-DCI based control signaling enhancements, the specification impacts include DMRS group portioning, DMRS indication table, TM definition, etc. For <NUM>-DCI based control signaling enhancements, the specification impacts include either a new DMRS mapping table or a new method to dynamiccaly indicate which DMRS port subset is QCL with which CSI-RS.

<CIT> relates to a wireless communication system. A method by which a terminal cancels interference and receives data in a wireless communication system, according to one embodiment of the present invention, comprises the steps of receiving first downlink control information (DCI) including scheduling information for receiving a physical downlink shared channel (PDSCH) from a base station, receiving second DCI including scheduling information on an interference channel from a second base station, and canceling the interference from the second base station on the basis of the first DCI and the second DCI, and receiving the PDSCH.

In <NPL>, CW-to-layer mapping can be configured for joint transmission of MIMO layers from multiple TPs. Potential specification enhancements may include one or more of the following two approaches: Approach <NUM>: Single DCI approach - Configuration of CW-to-layer mapping for each CW and Approach <NUM>: Multiple DCI approach - Support of single codeword for initial transmission with multiple MIMO layers.

Embodiments and examples not covered by the claims are meant to illustrate, and facilitate the understanding of, the claimed invention.

This application provides a multi-codeword transmission method and an apparatus, to resolve a problem that a terminal device cannot correctly demodulate data in a multi-codeword transmission scenario.

According to an aspect, a multi-codeword transmission method is provided, according to claim <NUM>. The network device generates the downlink control information corresponding to each of the plurality of code words to be sent to the terminal device, and the terminal device may demodulate data based on the downlink control information corresponding to the plurality of code words. This ensures that the terminal device correctly demodulates data in a multi-codeword transmission scenario.

According to another aspect, a multi-codeword transmission method is provided, according to claim <NUM>. The terminal device receives the downlink control information that is corresponding to each of the plurality of code words and that is generated by the network device, and may demodulate the data based on the downlink control information corresponding to the plurality of code words. This ensures correct data demodulation.

According to still another aspect, a network device is provided according to claim <NUM>.

Based on an inventive concept the same as that of the foregoing method, for a principle for resolving a problem by the apparatus and a beneficial effect brought by the apparatus, refer to the foregoing possible implementations of the method performed by the network device and beneficial effects brought by the implementations. Therefore, for implementation of the apparatus, refer to the implementation of the method, and repeated content is not described again.

According to still another aspect, a terminal device is provided according to claim <NUM>.

Based on an inventive concept the same as that of the foregoing method, for a principle for resolving a problem by the apparatus and a beneficial effect brought by the apparatus, refer to the foregoing possible implementations of the method performed by the terminal device and beneficial effects brought by the implementations. Therefore, for implementation of the apparatus, refer to the implementation of the method, and repeated content is not described again.

Yet another aspect of this application provides a computer program product according to claim <NUM> and a computer program product according to claim <NUM>.

To describe the technical solutions in embodiments of the present invention or in the background more clearly, the following describes the accompanying drawings required for describing the embodiments of the present invention or the background.

The following describes the embodiments of the present invention with reference to accompanying drawings in the embodiments of the present invention.

A communications system in the embodiments of the present invention includes a network device and a terminal device. The network device controls multi-codeword transmission of a transmission node. The communications system may be a global system for mobile communications (Global System for Mobile Communication, GSM) system, a code division multiple access (Code Division Multiple Access, CDMA) system, a wideband code division multiple access (Wideband Code Division Multiple Access, WCDMA) system, a worldwide interoperability for microwave access (Worldwide Interoperability for Microwave Access, WiMAX) system, a long term evolution (long term evolution, LTE) system, a <NUM> communications system (for example, a new radio (new radio, NR) system), a communications system that integrates various communications technologies (for example, a communications system that integrates an LTE technology and an NR technology), or a subsequent evolved communications system.

The terminal device in this application is a device having a wireless communication function. The terminal device may be a handheld device, an in-vehicle device, a wearable device, or a computing device that has the wireless communication function, another processing device connected to a wireless modem, or the like. In different networks, the terminal device may have different names such as user equipment (User Equipment, UE), an access terminal, a subscriber unit, a subscriber station, a mobile station, a mobile console, a remote station, a remote terminal, a mobile device, a subscriber terminal, a terminal, a wireless communications device, a user agent or a user apparatus, a cellular phone, a cordless telephone set, a session initiation protocol (Session Initiation Protocol, SIP) phone, a wireless local loop (Wireless Local Loop, WLL) station, a personal digital assistant (Personal Digital Assistant, PDA), or a terminal device in a <NUM> network or a future evolved network.

The network device in this application is a device that is deployed in a radio access network to provide a wireless communication function. The network device includes but is not limited to: a base station (for example, a BTS (Base Transceiver Station, BTS), a NodeB (NodeB, NB), an evolved NodeB (Evolutional Node B, eNB or eNodeB), a transmission node (for example, a transmission/reception point (transmission reception point, TRP) or a transmission point (Transmission Point, TP) in an NR system, or a next-generation NodeB (generation nodeB, gNB), a base station or a network device in a future communications network, a relay node, an access point, an in-vehicle device, a wearable device, a wireless fidelity (Wireless-Fidelity, Wi-Fi) site, a wireless backhaul node, a small cell, a micro cell, and the like. In existing LTE and LTE-A protocols, a downlink control channel corresponds to one or two code words during coordinated multipoint transmission/reception (Coordinated Multiple Points Transmission, CoMP). When a downlink control channel carries scheduling information of a plurality of code words, by default in a system, a plurality of code words carried on a physical downlink shared channel (Physical Downlink Shared Channel, PDSCH) are from one transmission node or from a plurality of transmission nodes synchronized with each other in time/frequency domain. In other words, the plurality of code words have a same large-scale channel experience. The large-scale channel experience includes the following features: delay spread (delay spread), Doppler spread (Doppler spread), Doppler shift (Doppler shift), an average gain (average gain), an average delay (average delay), a receive beam number of a terminal device, a transmit/receive channel correlation, a received angle of arrival (Angle-of-Arrival, AoA), a spatial correlation of a receiver antenna, a primary angle of arrival, an average angle of arrival, AoA spread, and the like. However, in downlink control information, only one set of the following parameters is included: a physical downlink shared channel resource element mapping and quasi-co-location indicator (PDSCH RE Mapping and Quasi-Co-Location Indicator), and an antenna port(s), scrambling identity and number of layers (Antenna Port(s), Scrambling identity and number of layers).

For multi-codeword transmission performed in an NCJT scenario, different code words are transmitted by different transmission nodes; and each transmission node separately performs self-adaptive precoding, that is, a plurality of code words correspond to different large-scale channel experiences, and time/frequency domain resources carried by the plurality of code words may be different. If demodulation of the plurality of code words is implemented according to an existing protocol by using one set of parameters of the PDSCH resource element mapping and quasi-co-location indicator, a high bit error rate of data transmission is caused. Therefore, in actual transmission, downlink control information matching a PDSCH for each transmission node should be considered. In addition, fixed information about an antenna port(s), scrambling identity and number of layers does not match a decoding requirement of all transmission nodes either. A PDSCH resource element mapping is used as an example. As shown in <FIG>, actual PDSCH resource element mapping information carried in different code words may be exactly the same (as shown in <FIG>), partially the same (as shown in <FIG>), or even completely different (as shown in <FIG>). Therefore, existing configuration information cannot ensure that downlink control information such as a PDSCH resource element mapping and quasi-co-location indicator, and an antenna port(s), scrambling identity and number of layers matches that of all transmission nodes in a case of multi-codeword transmission performed in the NCJT scenario.

The embodiments of the present invention provide a multi-codeword transmission method and an apparatus. A network device generates downlink control information corresponding to each of a plurality of code words to be sent to a terminal device, and the terminal device may demodulate data based on the downlink control information corresponding to the plurality of code words. This ensures that the terminal device correctly demodulates data in a multi-codeword transmission scenario.

Multi-codeword transmission scenarios in the embodiments of the present invention include: coordinated multipoint transmission/reception, for example, NCJT; multi-codeword transmission performed by using a plurality of beam groups used for one transmission node, for example, high frequency communication based on a plurality of simulated narrow beams; and multi-codeword transmission performed by using different antenna panels used for one transmission node, for example, high frequency communication based on a plurality of panels (multiple panels).

<FIG> is a schematic interaction diagram of a multi-codeword transmission method according to an embodiment of the present invention. The method includes the following steps:
S101. A network device generates downlink control information corresponding to each of a plurality of code words to be sent to a terminal device.

In this embodiment, the plurality of code words from a plurality of beam groups used for one transmission node, for example, a plurality of code words used in high frequency communication that is based on a plurality of simulated narrow beams; or is from different antenna panels used for one transmission node, for example, a plurality of code words in high frequency communication based on multiple panels. Optionally, the terminal device may be one terminal device or different terminal devices. In this embodiment, before the plurality of transmission nodes, the plurality of beam groups used for one transmission node, or the different antenna panels used for one transmission node send code words, the network device generates the downlink control information (Downlink Control Information, DCI) corresponding to each of the plurality of code words to be sent to the terminal device. The downlink control information corresponding to each code word includes at least a PDSCH resource element mapping and quasi-co-location indicator, and at least one of the following: an antenna port(s), scrambling identity and number of layers. The downlink control information corresponding to each code word includes the PDSCH resource element mapping and quasi-co-location indicator, and the antenna port(s), scrambling identity and number of layers.

The PDSCH mapping and quasi-co-location indicator is used to indicate a quasi-co-location relationship between antenna ports, and corresponds to a quasi-co-location relationship between reference signals of different types. Specifically, the PDSCH resource element mapping and quasi-co-location indicator includes at least one of the following parameters: a PDSCH start point, a multicast-broadcast single-frequency network (Multicast-Broadcast Single Frequency Network, MBSFN) subframe configuration, a beam management reference signal configuration, and a channel state information-reference signal (Channel State Information Reference Signal, CSI-RS) configuration. Herein, the reference signals of different types include a beam management reference signal, a CSI-RS, and a demodulation reference signal (Demodulation Reference Signal, DMRS). The beam management reference signal is used to measure a simulated beam, the CSI-RS is used to measure channel state information, and the DMRS is used to demodulate data. The beam management reference signal, the CSI-RS, and the DMRS have a quasi-co-location relationship. This means that one transmission node, one beam group of the same transmission node, or a group of antenna ports of one antenna panel of the transmission node have a same large-scale channel feature. Different transmission points, different beam groups, or different antenna panels that send a plurality of code words correspond to at least two groups of antenna ports. Large-scale channel features may include delay spread, an average delay, Doppler spread, Doppler shift, an average gain, a receive beam number of a terminal device, a transmit/receive channel correlation, a received angle of arrival, a spatial correlation of a receiver antenna, a primary angle of arrival, an average angle of arrival, AoA spread, and the like. Specifically, a quasi-co-location indicator is used to indicate whether at least two groups of antenna ports have a quasi-co-location relationship as follows: The quasi-co-location indicator is used to indicate whether reference signals sent by the at least two groups of antenna ports are from one transmission point; the quasi-co-location indicator is used to indicate whether reference signals sent by the at least two groups of antenna ports are from one beam group; or the quasi-co-location indicator is used to indicate whether reference signals sent by the at least two groups of antenna ports are from one antenna panel.

The antenna port(s), scrambling identity and number of layers is used to indicate a DMRS port, a DMRS scrambling identity, and a quantity of DMRS layers that correspond to a current code word. In an LTE protocol, a relationship between a DMRS port number and a quantity of DMRS transport layers is: a UE-specific reference signal related to a PDSCH is transmitted from the following antenna ports: p=<NUM>, p=<NUM>, p=<NUM>, p=<NUM>, p=<NUM>, p={<NUM>, <NUM>}, or p=<NUM>, <NUM>,. , v+<NUM>, where v is the quantity of transport layers used for a PDSCH. The DMRS scrambling identity is used to determine a DMRS sending sequence. For detailed definition and application of this parameter, refer to the LTE protocol, and details are not described herein again one by one.

The two parameters, the PDSCH resource element mapping and quasi-co-location indicator and the antenna port(s), scrambling identity and number of layers, are closely related to a code word. If a plurality of code words are transmitted, and the plurality of code words are from different transmission nodes, different beam groups, or different antenna panels, and when a set of the two parameters is used for the plurality of code words, data demodulation fails.

Further, the downlink control information corresponding to each code word further includes at least one of the following: a modulation and coding scheme (Modulation and Coding Scheme, MCS), a new data indicator (New Data Indicator, NDI), and a redundancy version (Redundancy Version, RV). The MCS is used to provide information related to a modulation mode, an encoding rate, and a transport block size to the terminal device. The NDI is used to empty a soft buffer for initial transmission. For detailed definition and application of these parameters, refer to the LTE protocol, and details are not described herein again one by one.

In addition to the downlink control information corresponding to each code word, downlink control information may further include more parameters. The following parameters may be transmitted in a DCI 2D format according to the existing LTE protocol. The downlink control information is used by the terminal device to demodulate data. An example in which two TPs transmit two codes words for one UE at a same time is provided, and a case in which more than two code words are transmitted is excluded. The DCI sent by the two TPs includes:.

In an implementation, the PDSCH resource element mapping and quasi-co-location indicator, and the antenna port(s), scrambling identity and number of layers may be included in one parameter set, or included in different parameter sets. Specifically, in an optional manner, the two parameters, the PDSCH resource element mapping and quasi-co-location indicator, and the antenna port(s), scrambling identity and number of layers, are included in different parameter sets, that is, the two parameters are represented by using parameter sets of two domains. For example, in the foregoing DCI parameter that is used as an example, the two parameters are separately represented. In another optional manner, the two parameters, the PDSCH resource element mapping and quasi-co-location indicator, and the antenna port(s), scrambling identity and number of layers, are included in one parameter set, that is, the two parameters are represented by using a parameter set of one domain. In other words, the PDSCH resource element mapping and quasi-co-location indicator carries an antenna port, a scrambling identity, and a quantity of layers. Specifically, the PDSCH resource element mapping and quasi-co-location indicator includes at least one of the following parameters: a PDSCH start point, a multicast-broadcast single-frequency network subframe configuration, a beam management reference signal configuration, and a channel state information-reference signal configuration, a DMRS port, a DMRS scrambling information, and a quantity of DMRS layers.

The network device sends downlink control information corresponding to the plurality of code words to the terminal device.

The network device may send, through a physical downlink control channel (Physical Downlink Control Channel, PDCCH), the downlink control information corresponding to the plurality of code words to the terminal device. Alternatively, the network device may send, through a plurality of PDCCHs, the downlink control information corresponding to the plurality of code words to the terminal device. The terminal device receives the downlink control information that is corresponding to the plurality of code words and that is from the network device.

The terminal device demodulates data based on the downlink control information corresponding to the plurality of code words.

As the terminal device receives the downlink control information corresponding to each code word, the downlink control information corresponding to the plurality of code words may be used to demodulate the data for the plurality of code words that are from different transmission nodes, different beam groups of one transmission node, or different antenna panels of one transmission node. For a specific data demodulation process, refer to an existing LTE protocol, and details are not described herein again.

According to the multi-codeword transmission method provided in this embodiment of the present invention, the network device generates the downlink control information corresponding to each of the plurality of code words to be sent to the terminal device, and the terminal device may demodulate data for the plurality of code words based on the downlink control information corresponding to the plurality of code words. This ensures that the terminal device correctly demodulates data in a multi-codeword transmission scenario.

The foregoing describes in detail the method in the embodiments of the present invention, and the following provides the apparatuses in the embodiments of the present invention.

<FIG> is a schematic module diagram of a network device according to an embodiment of the present invention. The network device <NUM> may include a processing unit <NUM> and a sending unit <NUM>. The processing unit <NUM> may be configured to control an operation of the network device, for example, perform S101 of generating downlink control information corresponding to each of a plurality of code words to be sent to a terminal device. The sending unit <NUM> may be configured to communicate with the terminal device, for example, perform S102 of sending the downlink control information corresponding to the plurality of code words to the terminal device. For details, refer to the description in the method embodiment, and details are not described herein again.

According to the network device provided in this embodiment of the present invention, the network device generates the downlink control information corresponding to each of the plurality of code words to be sent to the terminal device, and the terminal device may perform demodulation, based on the downlink control information corresponding to each code word, for the plurality of code words that are from different transmission nodes. This ensures correct demodulation.

<FIG> is a schematic module diagram of a terminal device according to an embodiment of the present invention. The terminal device <NUM> may include a receiving unit <NUM> and a demodulation unit <NUM>. The receiving unit <NUM> may be configured to communicate with a network device, for example, receive, after S102 is performed, the downlink control information that is corresponding to the plurality of code words and that is from the network device. The demodulation unit <NUM> may be configured to control an operation of the terminal device, for example, perform S103 of demodulating data based on the downlink control information corresponding to the plurality of code words. For details, refer to the description in the method embodiment, and details are not described herein again.

According to the terminal device provided in this embodiment of the present invention, the terminal device receives the downlink control information that is corresponding to each of the plurality of code words and that is generated by the network device, and may demodulate the data for the plurality of code words based on the downlink control information corresponding to the plurality of code words. This ensures that the terminal device correctly demodulates data in a multi-codeword transmission scenario.

<FIG> is an architectural diagram of hardware of a network device according to an embodiment of the present invention. The network device <NUM> may include a transceiver <NUM>, a processor <NUM>, and a memory <NUM>. The transceiver <NUM>, the processor <NUM>, and the memory <NUM> are connected to each other by using a bus <NUM>. A related function implemented by the processing unit <NUM> in <FIG> may be implemented by one or more processors <NUM>, and a related function implemented by the sending unit <NUM> in <FIG> may be implemented by the transceiver <NUM>.

The memory <NUM> includes but is not limited to a random access memory (Random Access Memory, RAM), a read-only memory (Read-Only Memory, ROM), an erasable programmable read only memory (Erasable Programmable Read Only Memory, EPROM), or a compact disc read-only memory (Compact Disc Read-Only Memory, CD-ROM). The memory <NUM> is configured to store a related instruction and data.

The transceiver <NUM> is configured to send data and/or a signal and receive data and/or a signal. The transmitter and the receiver perform a sending operation and a receiving operation, respectively. The transmitter and the receiver may be independent components, or may be an integral component.

The processor <NUM> may include one or more processors, for example, include one or more central processing units (Central Processing Unit, CPU). When the processor <NUM> is one CPU, the CPU may be a single-core CPU, or may be a multi-core CPU.

The processor <NUM> is configured to support the network device in performing step S101, shown in <FIG>, of generating downlink control information corresponding to each of a plurality of code words to be sent to a terminal device. The memory <NUM> is configured to store program code and data of the network device.

The transceiver <NUM> is configured to communicate with the terminal device, and perform step S102, shown in <FIG>, of sending the downlink control information corresponding to the plurality of code words to the terminal device.

For details about steps performed by the processor <NUM> and the transceiver <NUM>, refer to descriptions of the embodiment shown in <FIG>, and details are not described herein again.

It may be understood that <FIG> shows only a simplified design of the network device. In an actual application, each network device may further include another necessary component that includes but is not limited to: any quantity of transceivers, any quantity of processors, any quantity of controllers, and any quantity of memories. In addition, all network devices that can implement the present invention fall in the protection scope of the present invention.

According to the network device provided in this embodiment of the present invention, the network device generates the downlink control information corresponding to each of the plurality of code words to be sent to the terminal device, and the terminal device may demodulate data for the plurality of code words based on the downlink control information corresponding to the plurality of code words. This ensures that the terminal device correctly demodulates data in a multi-codeword transmission scenario.

<FIG> is a schematic architectural diagram of hardware of a terminal device according to an embodiment of the present invention. The terminal device <NUM> may include a transceiver <NUM>, a processor <NUM>, and a memory <NUM>. The transceiver <NUM>, the processor <NUM>, and the memory <NUM> are connected to each other by using a bus <NUM>. A related function implemented by the demodulation unit <NUM> in <FIG> may be implemented by one or more processors <NUM>, and a related function implemented by the receiving unit <NUM> in <FIG> may be implemented by the transceiver <NUM>.

The memory <NUM> includes but is not limited to a random access memory, a read-only memory, an erasable programmable read only memory, or a compact disc read-only memory. The memory <NUM> is configured to store a related instruction and data.

The processor <NUM> may include one or more processors, for example, include one or more central processing units. When the processor <NUM> is one CPU, the CPU may be a single-core CPU, or may be a multi-core CPU.

The processor <NUM> is configured to support the terminal device in performing step S103, shown in <FIG>, of demodulating data based on the downlink control information corresponding to the plurality of code words. The memory <NUM> is configured to store program code and data of the terminal device.

The transceiver <NUM> is configured to: communicate with the terminal device, perform step S102 shown in <FIG>, and receive the downlink control information that is corresponding to the plurality of code words and that is from the network device.

It may be understood that <FIG> shows only a simplified design of the terminal device. In an actual application, each terminal device may further include another necessary component that includes but is not limited to: any quantity of transceivers, any quantity of processors, any quantity of controllers, and any quantity of memories. In addition, all terminal devices that can implement the present invention fall in the protection scope of the present invention.

According to the terminal device provided in this embodiment of the present invention, the terminal device receives the downlink control information that is corresponding to each of the plurality of code words and that is generated by the network device, and may demodulate data for the plurality of code words based on the downlink control information corresponding to the plurality of code words. This ensures that the terminal device correctly demodulates data in a multi-codeword transmission scenario.

A person of ordinary skill in the art may be aware that, the units and algorithm steps in the examples described with reference to the embodiments disclosed in this specification may be implemented by electronic hardware or a combination of computer software and electronic hardware.

It may be clearly understood by a person skilled in the art that, for the purpose of convenient and brief description, for a detailed working process of the system, apparatus, and unit, refer to a corresponding process in the method embodiments.

The indirect couplings or communication connections between the apparatuses or units may be implemented in electrical, mechanical, or other forms.

Claim 1:
A multi-codeword transmission method, comprising:
generating (S101), by a network device, downlink control information corresponding to each of a plurality of code words to be sent to a terminal device, wherein the plurality of code words are from different beam groups of one transmission node or different antenna panels of one transmission node, wherein the downlink control information corresponding to each code word comprises a physical downlink shared channel PDSCH resource element mapping and quasi-co-location indicator and at least one of the following: an antenna port(s), a scrambling identity and a number of layers; and
sending (S102), by the network device, downlink control information corresponding to each of the plurality of code words to the terminal device.