Patent Description:
In a <NUM> New Radio (NR) system, Hybrid Automatic Repeat reQuest Acknowledgment (HARQ-ACK) may be adopted to feed back to a transmitter. In HARQ-ACK technology, a receiver usually checks whether a received data packet is correct. If there is no error, the receiver may transmit an ACK to the transmitter. After receiving the ACK, the transmitter may continue to transmit a next data packet. If there is an error, the receiver may transmit a Negative Acknowledgment (NACK) to the transmitter, and the transmitter may retransmit the same data packet after receiving the NACK. However, when performing HARQ-ACK feedback to the transmitter, it often occurs that multiple consecutive Downlink Control Information (DCI) are missed for detection, which leads to a feedback error during HARQ-ACK feedback.

In the current NR system, a base station can use Downlink Assignment Indicator (DAI) to indicate to a User Equipment (UE) a number of Physical Downlink Shared Channels (PDSCHs) transmitted by the base station at a current Physical Downlink Control Channel (PDCCH) monitoring occasion. Afterward, the UE determines the number of PDSCHs scheduled by the base station according to the DAI, and generates a corresponding HARQ codebook to report to the base station. Specifically, the HARQ codebook includes ACK/NACK information for each PDSCH.

The DAI is divided into Counter DAI (C-DAI) and Total DAI (T-DAI). The C-DAI indicates a cumulative number of {serving cell, PDCCH monitoring occasion} groups up to a current serving cell and a current PDCCH monitoring occasion. The T-DAI indicates a total number of {serving cell, PDCCH monitoring occasion} groups until the current PDCCH monitoring occasion.

However, the above solution is merely applicable to a case where single DCI schedules a single PDSCH. When single DCI schedules multiple PDSCHs, it is difficult for the UE to correctly determine a size of the HARQ codebook according to the received DAI, and thus cannot report a correct HARQ codebook.

A method for determining a downlink assignment indicator is required, to enable a UE to correctly determine a number of missed detections for PDSCHs, thereby facilitate the UE to correctly report a HARQ codebook.

<CIT> discloses a method for determining feedback information. The method includes: obtaining, by a receive end device, time unit aggregation information and DAI indication information that are sent by a transmit end device; determining feedback information for at least one transport block based on the time unit aggregation information and the DAI indication information; and finally sending the feedback information for the at least one transport block to the transmit end device.

<CIT> discloses a method for codebook transmission. The method includes receiving at least one downlink transmission and indication information corresponding to the at least one downlink transmission and generating a codebook including at least one piece of feedback information corresponding to the at least one downlink transmission. The at least one downlink transmission includes a target downlink transmission corresponding to an actual occasion and a pair of a target frequency domain resource and a reference occasion. A location of feedback information corresponding to the target downlink transmission in the codebook corresponds to indication information corresponding to the target downlink transmission. The actual occasion includes a PDCCH monitoring occasion at which DCI for scheduling or carrying the target downlink transmission is located or a PDSCH reception occasion at which the target downlink transmission is located.

<CIT> discloses a PUCCH sending method and a PUCCH receiving method. The PUCCH sending method comprises the steps: receiving at least two downlink transmissions, HARQ-ACKs of the at least two downlink transmissions being transmitted in the same time unit; determining PUCCH resources for transmitting HARQ-ACKs of the at least two downlink transmissions according to the PUCCH resources indicated by the PRI in the downlink control information DCI used by the PDCCHs corresponding to the at least two downlink transmissions respectively; and sending the corresponding HARQ-ACK of the downlink transmission on the determined PUCCH resource.

The invention is defined by the subject-matter of the appended set of claims.

The present disclosure provides a method and device for determining a downlink assignment indicator, a method and device for configuring a downlink assignment indicator, a storage medium, a terminal, and a base station, which enables a UE to discover a number of missed detections of PDSCH in time, and improves accuracy of HARQ codebooks.

As described in the background, in the current NR system, a base station can use DAI to indicate to a UE a number of PDSCHs transmitted by the base station at a current PDCCH monitoring occasion. Afterward, the UE determines the number of PDSCHs scheduled by the base station according to the DAI, and generates a corresponding HARQ codebook to report to the base station. However, the above solution is merely applicable to a case where single DCI schedules a single PDSCH. When single DCI schedules multiple PDSCHs, it is difficult for the UE to correctly determine a size of the HARQ codebook according to the received DAI, and thus cannot report a correct HARQ codebook.

Inventors of this invention found through research that in existing techniques, a UE can directly determine a number of PDCCHs according to a PDCCH monitoring occasion in DAI. If single DCI schedules a single PDSCH, a number of PDSCHs and the number of PDCCHs are equal, and the UE can determine missed detection of PDCCH when a hop occurs in the number of PDCCHs, determine the number of missed PDCCHs according to the number of hops of PDCCHs, and then report a HARQ codebook according to a correct codebook size. However, if single DCI schedules multiple PDSCHs, the number of PDSCHs is greater than the number of PDCCHs. Even if the UE determines a missed detection of PDCCH when a hop occurs in the number of PDCCHs and determines the number of hops of PDCCHs, the number of missed detections of PDSCHs cannot be determined, resulting in inability to determine the correct codebook size when reporting the HARQ codebook.

By configuring that C-DAI field indication information indicates a cumulative number of PDSCHs scheduled by a PDCCH up to a current serving cell and a current PDCCH monitoring occasion, a UE receiving DCI determines a total number of PDSCHs that should be received based on the C-DAI field indication information in the DCI, which is conducive to discovering a number of missed detections of PDSCH in time, and improves accuracy of HARQ codebooks.

Referring to <FIG> is a flow chart of a method for determining a downlink assignment indicator. The method is applied to a UE and includes S11 and S12.

In S11, the UE receives DCI which includes C-DAI field indication information, wherein the C-DAI field indication information indicates a cumulative number of PDSCHs scheduled by a PDCCH up to a current serving cell and a current PDCCH monitoring occasion.

In S12, the UE determines a HARQ codebook based on the DCI.

In some embodiments, the method may be implemented in a manner of software programs which are run on a processor integrated within a chip or a chip module.

In S11, a base station indicates the cumulative number of PDSCHs scheduled by the PDCCH up to the current serving cell and the current PDCCH monitoring occasion through one or more C-DAI field indication information in the DCI.

<FIG> is a diagram of C-DAI field indication information and T-DAI field indication information.

The embodiment as shown in <FIG> is applicable to two serving cells (Serving Cells), and the PDCCH schedules multiple PDSCHs at multiple PDCCH monitoring occasions.

Numbers marked in boxes (such as the number <NUM> or <NUM>) are the numbers of PDSCHs scheduled by the PDCCH in the corresponding serving cell, and two numbers in brackets (such as (<NUM>, <NUM>) or (<NUM>, <NUM>)) are the C-DAI field indication information and T-DAI field indication information, namely (C-DAI field indication information and T-DAI field indication information).

Specifically, at a first PDCCH monitoring occasion, the PDCCH schedules <NUM> PDSCHs in the first serving cell, and the C-DAI field indication information indicates the total number of PDSCHs scheduled by the PDCCH, which is <NUM>. At the same time, the PDCCH schedules two PDSCHs in the second serving cell, and the C-DAI field indication information indicates the total number of PDSCHs scheduled by the PDCCH, which is (<NUM>+<NUM>=<NUM>).

In some embodiments, if the UE fails to receive the PDCCH at the first PDCCH monitoring occasion of the first serving cell, after receiving all two PDSCHs of the second serving cell, the UE may discover that (<NUM>-<NUM>=<NUM>) PDSCHs were missed according to the C-DAI field indication information of <NUM> in time.

It could be understood that the T-DAI field indication information follows a representation method in the existing techniques, that is, as there are two {serving cell, PDCCH monitoring occasion} groups until the current PDCCH monitoring occasion, the T-DAI field indication information is <NUM>.

It should be noted that if the C-TAI field indication information follows a representation method in the existing techniques, that is, the C-DAI field indication information indicates a cumulative number of {serving cell, PDCCH monitoring occasion} groups up to a current serving cell and a current PDCCH monitoring occasion, the cumulative numbers are <NUM> and <NUM> respectively, that is, no matter for the first serving cell or the second serving cell, (C-DAI field indication information, T-DAI field indication information) are both (<NUM>, <NUM>).

From above, in the existing techniques, if the UE fails to completely receive all <NUM> PDSCHs in the first serving cell, for example, merely <NUM> PDSCHs are received, the UE cannot discover in time a missed detection of the PDSCH based on the C-DAI field indication information of <NUM> and the T-DAI field indication information of <NUM>. The embodiments of the present disclosure may overcome deficiencies in the existing techniques.

Further, at the second PDCCH monitoring occasion, the PDCCH schedules <NUM> PDSCHs in the second serving cell, and the C-DAI field indication information indicates the total number of PDSCHs scheduled by the PDCCH, which is (<NUM>+<NUM>=<NUM>). At the third PDCCH monitoring occasion, the PDCCH schedules <NUM> PDSCHs in the first serving cell, and the C-DAI field indication information indicates the total number of PDSCHs scheduled by the PDCCH, which is (<NUM>+<NUM>=<NUM>). At the fourth PDCCH monitoring occasion, the PDCCH schedules <NUM> PDSCHs in the second serving cell, and the C-DAI field indication information indicates the total number of PDSCHs scheduled by the PDCCH, which is (<NUM>+<NUM>=<NUM>).

Still referring to <FIG>, in S12, the UE determines the HARQ codebook based on the DCI.

Further, the UE determines the HARQ codebook based on the C-DAI field indication information.

In embodiments of the present disclosure, by configuring that C-DAI field indication information indicates a cumulative number of PDSCHs scheduled by a PDCCH up to a current serving cell and a current PDCCH monitoring occasion, a UE receiving DCI may determine a total number of PDSCHs that should be received based on the C-DAI field indication information in the DCI, which is conducive to discovering a number of missed detections of PDSCH in time, and improves accuracy of HARQ codebooks.

In some embodiments, said determining the HARQ codebook based on the C-DAI field indication information includes: determining a number of ACK/NACK information contained in the HARQ codebook based on the cumulative number of the PDSCHs indicated by the C-DAI field indication information, wherein each ACK/NACK information is in one-to-one correspondence with one of the PDSCHs.

In some embodiments, the C-DAI field indication information is carried in a last detected PDCCH which is the last PDCCH indicating a PUCCH or PUSCH carrying the HARQ codebook.

Taking the embodiment shown in <FIG> as an example, when <NUM> PDSCHs are received at the fourth PDCCH monitoring occasion, the UE can determine that a size of the reported HARQ codebook is <NUM>, that is, including <NUM> pieces of ACK/NACK information. For example, a missed detection of PDCCH occurs at the third monitoring occasion on the first serving cell. The UE determines that the number of PDSCHs missed at the third PDCCH monitoring occasion is (<NUM>-<NUM>-<NUM>=<NUM>) based on the number of PDSCHs at the second PDCCH monitoring occasion being <NUM>, the number of PDSCHs at the fourth PDCCH monitoring occasion being <NUM>, and the total number being <NUM>.

Further, when reporting the HARQ codebook, the UE may mark all four PDSCHs missed at the third PDCCH monitoring occasion as missed detection.

Further, for the missed PDSCHs, the ACK/NACK information may include NACK and/or <NUM>-bit missed detection indication information.

Specifically, taking the missed detection of <NUM> PDSCHs at the third PDCCH monitoring occasion as an example. If the ACK/NACK information is <NUM>-bit missed detection indication information, the HARQ codebook reported by the UE may be (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), where the first ten <NUM> indicate that there is no missed detection from the first PDCCH monitoring occasion to the second PDCCH monitoring occasion, the middle four <NUM> indicate that <NUM> PDSCHs are missed at the third PDCCH monitoring occasion, and the last two <NUM> indicate that there is no missed detection is at the fourth PDCCH monitoring occasion.

It could be understood that if ACK/NACK information is NACK for the missed PDSCH, "<NUM>" in the <NUM>-bit missed detection indication information may be replaced with ACK, and "<NUM>" therein may be replaced with NACK.

In the embodiments of the present disclosure, the cumulative number of the PDSCHs indicated by the C-DAI field indication information may serve as the number of ACK/NACK information contained in the HARQ codebook, and each ACK/NACK information is in one-to-one correspondence with one of the PDSCHs, so that the UE may explicitly mark the missed PDSCHs in the reported HARQ codebook to improve effectiveness and accuracy of feedback.

The DCI further includes T-DAI field indication information which indicates a total number of PDSCHs scheduled by the PDCCH until the current PDCCH monitoring occasion; and said determining a HARQ codebook based on the DCI includes: determining the HARQ codebook based on the T-DAI field indication information.

As shown in <FIG> is also applicable to two serving cells (Serving Cells), and the PDCCH schedules multiple PDSCHs at multiple PDCCH monitoring occasions.

It should be noted that the representation of the C-DAI field indication information as shown in <FIG> is the same as that in <FIG>, and is not repeated here. In <FIG>, the T-DAI field indication information and the C-DAI field indication information represent the same meaning, which indicates the total number of PDSCHs scheduled by the PDCCH at the current PDCCH monitoring occasion.

The DCI also includes the T-DAI field indication information. As algorithms/formulas involved in HARQ codebooks in existing techniques are usually implemented based on T-DAI field indication information, the UE determines, after receiving the DCI, a total number of PDSCHs that should be received until the current PDCCH monitoring occasion based on the T-DAI field indication information in the DCI, which is conducive to timely discovery of a number of missed detections of PDSCH, and improves adaptability to solutions in the existing techniques.

The C-DAI field indication information and the T-DAI field indication information are represented by consecutive character strings, and a character string representing the C-DAI field indication information is located in front of a character string representing the T-DAI field indication information.

The base station configures the DCI in a manner of (C-DAI field indication information, T-DAI field indication information). (C-DAI field indication information, T-DAI field indication information) adopts N-bit character strings, where the C-DAI field indication information uses the first N1-bit character string, the T-DAI field indication information uses the following N2-bit character string, N1 and N2 are both natural numbers, and N1+N2=N.

The C-DAI field indication information and the T-DAI field indication information are represented by consecutive character strings, and a character string representing the C-DAI field indication information is located in front of a character string representing the T-DAI field indication information, which enables the UE to more accurately determine contents of the C-DAI field indication information and the T-DAI field indication information.

<FIG> is a flow chart of a method for configuring a downlink assignment indicator. The method is applied to a base station and includes S41 and S42.

In S41, the base station configures DCI which includes C-DAI field indication information, wherein the C-DAI field indication information indicates a cumulative number of PDSCHs scheduled by a PDCCH up to a current serving cell and a current PDCCH monitoring occasion.

In S42, the base station transmits the DCI to make a UE determine a HARQ codebook based on the DCI.

The DCI further includes T-DAI field indication information which indicates a total number of PDSCHs scheduled by the PDCCH until the current PDCCH monitoring occasion; and said transmitting the DCI to make a UE determine a HARQ codebook based on the DCI includes: transmitting the DCI to make the UE determine the HARQ codebook based on the T-DAI field indication information.

The C-DAI field indication information and the T-DAI field indication information are represented by consecutive character strings.

More details of S41 and S42 can be referred to related descriptions of S11 and S12 as shown in <FIG>, and are not repeated here.

Referring to <FIG> is a structural diagram of a device for determining a downlink assignment indicator. The apparatus is applied to a UE and includes a receiving circuitry <NUM> configured to receive DCI which includes C-DAI field indication information, wherein the C-DAI field indication information indicates a cumulative number of PDSCHs scheduled by a PDCCH up to a current serving cell and a current PDCCH monitoring occasion; and a codebook determining circuitry <NUM> configured to determine a HARQ codebook based on the DCI.

The apparatus corresponds to a chip with a data processing function in a UE, or to a chip module including a chip with a data processing function in the UE, or to the UE.

Principles, specific implementation manners and advantages of the device for determining the downlink assignment indicator can be referred to related descriptions of the method for determining the downlink assignment indicator, and are not repeated here.

Referring to <FIG> is a structural diagram of a device for configuring a downlink assignment indicator. The apparatus is applied to a base station and includes a codebook determining circuitry <NUM> configured to configure DCI which includes C-DAI field indication information, wherein the C-DAI field indication information indicates a cumulative number of PDSCHs scheduled by a PDCCH up to a current serving cell and a current PDCCH monitoring occasion; and a transmitting circuitry <NUM> configured to transmit the DCI to make a UE determine a HARQ codebook based on the DCI.

Principles, specific implementation manners and advantages of the device for configuring the downlink assignment indicator can be referred to related descriptions of the method for configuring the downlink assignment indicator, and are not repeated here.

A storage medium having computer instructions stored therein is provided, wherein when the computer instructions are executed, the above method is performed. In some embodiments, the storage medium may be a computer readable storage medium, and may include a non-volatile or a non-transitory memory, or include an optical disk, a magnetic disk or a solid disk.

In the embodiments of the present disclosure, the processor may be a Central Processing Unit (CPU), or other general processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other Programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, and the like. A general processor may be a microprocessor or the processor may be any conventional processor or the like.

It should also be understood that the memory in the embodiments of the present disclosure may be either volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memories. The non-volatile memory may be a Read-Only Memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be a Random Access Memory (RAM) which functions as an external cache. By way of example but not limitation, various forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM), Enhanced SDRAM (ESDRAM), Synchronous connection to DRAM (SLDRAM), and Direct Rambus RAM (DR-RAM).

A terminal including a memory and a processor is provided, wherein the memory has computer instructions stored therein, and when the processor executes the computer instructions, the above method is performed. The terminal may include but not limited to a mobile phone, a computer or a tablet computer.

The terminal may refer to various forms of UE, access terminal, user unit, user station, Mobile Station (MS), remote station, remote terminal, mobile equipment, user terminal, terminal equipment, wireless communication equipment, user agent or user device. The terminal equipment may further be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with a wireless communication function, a computing device or other processing devices connected to a wireless modems, an in-vehicle device, a wearable device, a terminal equipment in the future <NUM> network, or a terminal equipment in a future evolved Public Land Mobile Network (PLMN), which is not limited in the embodiments of the present disclosure.

A base station including a memory and a processor is provided, wherein the memory has computer instructions stored therein, and when the processor executes the computer instructions, the above method is performed.

The Base Station (BS) is also referred to as a base station equipment, and is a device deployed in a Radio Access Network (RAN) to provide radio communication functions. For example, an equipment that provides a base station function in a <NUM> network includes a Base Transceiver Station (BTS). An equipment that provides the base station function in a <NUM> network includes a Node B. An equipment that provides the base station function in a <NUM> network includes an evolved node B (eNB). In a Wireless Local Area Network (WLAN), an equipment that provides the base station function is an Access Point (AP). An equipment that provides the base station function in a <NUM> New Radio (NR) includes gNB and a continuously evolved Node B (ng-eNB), where gNB and the terminal use NR technology for communication, ng-eNB and the terminal use Evolved Universal Terrestrial Radio Access (E-UTRA) technology for communication, and both gNB and ng-eNB can be connected to a <NUM> core network. And the base station also refers to an equipment that provides the base station function in a new communication system in the future.

A base station controller in the embodiments of the present disclosure refers to an apparatus in charge of the base station, such as a Base Station Controller (BSC) in a <NUM> network, a Radio Network Controller (RNC) in a <NUM> network, or any apparatus that controls and manages the base station in new communication systems in the future.

The network in the embodiments of the present disclosure refers to a communication network that provides communication services for terminals, including a base station of a radio access network, a base station controller of a radio access network, and a device on a core network side.

Claim 1:
A method performed by a User Equipment, UE, for determining a downlink assignment indicator, comprising:
receiving (S11), from a base station, Downlink Control Information, DCI, which comprises Counter-Downlink Assignment Indicator, C-DAI, field indication information, wherein the C-DAI field indication information indicates a cumulative number of Physical Downlink Shared Channels, PDSCHs, scheduled by a Physical Downlink Control Channel, PDCCH, up to a current serving cell and a current PDCCH monitoring occasion; and
determining (S12) a Hybrid Automatic Repeat reQuest, HARQ, codebook based on the DCI;
wherein the DCI further comprises Total-Downlink Assignment Indicator, T-DAI, field indication information which indicates a total number of PDSCHs scheduled by the PDCCH until the current PDCCH monitoring occasion;
characterized in that the C-DAI field indication information and the T-DAI field indication information are represented by consecutive character strings, and a character string representing the C-DAI field indication information is located in front of a character string representing the T-DAI field indication information.