Methods and devices for sending HARQ-ACK / NACK and downlink transmission methods and devices

Abstract

A method and apparatus for transmitting HARQ-ACK / NACK, as well as a downlink transmission method and apparatus, are provided. The method for transmitting HARQ-ACK / NACK includes: a user equipment receiving a PDSCH and control signaling from a base station in a downlink time unit; the user equipment determining, based on the control signaling, an uplink time unit for feeding back HARQ-ACK / NACK corresponding to the received PDSCH, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the positions of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook; the user equipment generating the HARQ-ACK / NACK codebook based on the size of the HARQ-ACK / NACK codebook and the positions of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook; and the user equipment transmitting the HARQ-ACK / NACK codebook in the uplink time unit. This invention enables user equipment to accurately determine the size of the HARQ-ACK codebook and bit mapping when the HARQ-ACK feedback time is variable.

Description

[0001] This application is a divisional application of the application filed with the State Intellectual Property Office of the People's Republic of China on September 29, 2017, with application number 201710910258.9, entitled "Method and apparatus for sending HARQ-ACK / NACK and downlink transmission method and apparatus". Technical Field

[0002] This invention relates to the field of mobile communication technology, and more specifically, to a method and apparatus for sending HARQ (Hybrid Automatic Repeat Request) - ACK / NACK (Acknowledgement / Negation), as well as a downlink transmission method and apparatus. Background Technology

[0003] With the rapid development of the information industry, especially the growing demand from mobile internet and the Internet of Things (IoT), unprecedented challenges are being brought to future mobile communication technologies. According to the International Telecommunication Union (ITU) report ITU-R M. [IMT.BEYOND 2020.TRAFFIC], it is projected that by 2020, mobile traffic will increase nearly 1000 times compared to 2010 (the 4G era), and the number of connected user devices will exceed 17 billion. As massive numbers of IoT devices gradually penetrate mobile communication networks, the number of connected devices will be even more staggering. To address these unprecedented challenges, the communications industry and academia have launched extensive research into fifth-generation mobile communication technology (5G) for the 2020s. Currently, the ITU report ITU-R M. [IMT.VISION] discusses the framework and overall goals of future 5G, providing detailed explanations of 5G's demand outlook, application scenarios, and key performance indicators. In response to the new requirements of 5G, the ITU report ITU-R M. [IMT. FUTURE TECHNOLOGY TRENDS] provides information on technology trends related to 5G, aiming to address significant issues such as significantly improved system throughput, consistent user experience, scalability to support IoT, latency, energy efficiency, cost, network flexibility, support for emerging services, and flexible spectrum utilization. Within 3GPP, the first phase of work on 5G is already underway. To support more flexible scheduling, 3GPP has decided to support variable HARQ-ACK feedback latency in 5G. In existing LTE (Long Term Evolution) systems, the time from downlink data reception to uplink HARQ-ACK transmission is fixed; for example, in FDD (Frequency Division Duplex) systems, the latency is four subframes. In TDD (Time Division Duplex) systems, a HARQ-ACK feedback latency is determined for the corresponding downlink subframe based on the uplink and downlink configuration. In 5G systems, whether FDD or TDD, the uplink time unit for HARQ-ACK feedback is variable for a given downlink time unit (e.g., downlink time slot or downlink mini-time slot). For example, the HARQ-ACK feedback latency can be dynamically indicated by physical layer signaling, or different HARQ-ACK latency can be determined based on different services or user capabilities.

[0004] In 5G, when the HARQ-ACK latency is variable, even in FDD systems, the HARQ-ACK feedback required for a single uplink time unit may originate from downlink data across multiple downlink time units. Furthermore, the number of downlink time units requiring HARQ-ACK feedback is also variable, and often differs for each UE. Compared to existing TDD systems, due to the variable HARQ-ACK latency, the starting position and length of the HARQ-ACK feedback binding window are also variable. Moreover, in 5G, in addition to the transport block-based HARQ-ACK feedback mechanism used in existing LTE systems, coded block-based HARQ-ACK feedback can also be employed, thus increasing the overall overhead of HARQ-ACK. To achieve scheduling flexibility, HARQ-ACK feedback effectiveness, and a balance between downlink control signaling overhead supporting HARQ-ACK, a new method for sending and receiving HARQ-ACK feedback is urgently needed. Summary of the Invention

[0005] The present invention is provided to at least solve the above-mentioned problems and to provide at least the following advantages.

[0006] According to one aspect of the present invention, a method for transmitting HARQ-ACK / NACK is provided, comprising: a user equipment receiving a PDSCH (Physical Downlink Shared Channel) and control signaling from a base station in a downlink time unit; the user equipment determining, based on the control signaling, an uplink time unit for feeding back HARQ-ACK / NACK corresponding to the received PDSCH, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook; the user equipment generating the HARQ-ACK / NACK codebook based on the size of the HARQ-ACK / NACK codebook and the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook; and the user equipment transmitting the HARQ-ACK / NACK codebook in the uplink time unit.

[0007] The control signaling may be downlink scheduling signaling carried through PDCCH (Physical Downlink Control Channel) or control signaling carried through PDSCH.

[0008] The control signaling may include information about HARQ-ACK / NACK timing.

[0009] Information regarding HARQ-ACK / NACK timing can be one of the following: information indicating the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback; information indicating one or more uplink time units containing configured PUCCHs (Physical Uplink Control Channels) that are greater than or equal to the minimum time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback, and are closest to that minimum time difference; information indicating whether the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback is predefined, or whether the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback is predefined, and is closest to one or more uplink time units containing configured PUCCHs.

[0010] The number of bits for the HARQ-ACK / NACK timing information varies for different downlink control signaling (DCI) systems. The number of bits for the HARQ-ACK / NACK timing information in the DCI within the common search area of ​​the downlink control channel differs from that in the DCI within the user-dedicated search area.

[0011] The time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides HARQ-ACK / NACK feedback varies for different downlink control signaling (DCI). The time difference indicated by the DCI within the common search area of ​​the downlink control channel is predefined by the standard, while the time difference indicated by the DCI within the user-dedicated search area is configured by higher layers. The control signaling may also include a first type of DAI (Downlink Allocation Index) and / or a second type of DAI, wherein the first type of DAI indicates one of the following: the relative time order of the currently scheduled downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the bit position of the HARQ-ACK / NACK bit of the currently scheduled downlink time unit in the HARQ-ACK / NACK codebook.

[0012] In the control signaling, the first type of DAI can be co-encoded with information about HARQ-ACK / NACK timing.

[0013] The second type of DAI indicates one of the following: the total number of downlink time units of all scheduled downlink time units corresponding to the uplink time unit, the total number of downlink time units from the first downlink time unit to the current downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the total number of bits of the HARQ-ACK / NACK codebook indicated by the second type of DAI.

[0014] The control signaling may include a third type of DAI, wherein the content of the third type of DAI is the same as the content of the second type of DAI, or the third type of DAI indicates the total number of bits of the HARQ-ACK / NACK codebook that the base station expects to receive, and the total number of HARQ-ACK / NACK bits corresponding to the PDSCH actually scheduled by the base station is less than or equal to the expected total number of bits.

[0015] In the control signaling, the first type DAI, the second type DAI, and information about HARQ-ACK / NACK timing can be jointly encoded.

[0016] The step of determining the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit may include: calculating the size of the feedback window based on information about the HARQ-ACK / NACK timing, wherein the feedback window is a set of all downlink time units that may simultaneously feed back HARQ-ACK / NACK in the uplink time unit, determined by all possible values ​​of the HARQ-ACK timing; and obtaining the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit by combining the size of the feedback window with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit.

[0017] The step of determining the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit may include one of the following steps: determining the size of the HARQ-ACK / NACK codebook by combining the maximum value of the first type DAI of all scheduled downlink time units corresponding to the uplink time unit with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit; and determining the size of the HARQ-ACK / NACK codebook by combining the value of the second type DAI with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit when the second type DAI indicates the total number of downlink time units of all scheduled downlink time units corresponding to the uplink time unit. The size of the ACK codebook; when the second type DAI indicates the total number of downlink time units from the first downlink time unit to the current downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, the size of the HARQ-ACK / NACK codebook is determined by combining the maximum value of the second type DAI among all scheduled downlink time units corresponding to the uplink time unit with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit; when the second type DAI indicates the total number of bits in the HARQ-ACK / NACK codebook, the size of the HARQ-ACK / NACK codebook is determined based on the number of bits indicated by the second type DAI.

[0018] If a third type of DAI is indicated, the HARQ-ACK / NACK codebook is determined jointly based on the first, second, and third type of DAI. If the values ​​of the second and third type of DAI are inconsistent, the size of the HARQ-ACK / NACK codebook is determined based on the third type of DAI, and the order of the HARQ-ACK bits in the codebook is determined at least based on the first type of DAI.

[0019] The number of HARQ-ACK / NACK bits corresponding to each downlink time unit can be predefined by a standard or semi-statically configured. The number of HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on one of the following: the maximum number of transport blocks that can be transmitted per downlink time unit, the maximum number of coded blocks that can be transmitted per downlink time unit, or the maximum number of coded block groups that can be transmitted per downlink time unit. Preferably, for a specific carrier, when the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is configured based on the maximum number of coded block groups that can be transmitted per downlink time unit, the HARQ-ACK / NACK bits are determined according to the number of coded block groups, regardless of whether the downlink time unit is scheduled using transport block-based or coded block group-based scheduling signaling.

[0020] The control signaling may further include information indicating that the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on the maximum number of transport blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded block groups that can be transmitted in each downlink time unit.

[0021] The control signaling may also include the size of the HARQ-ACK / NACK codebook configured by the base station.

[0022] The step of determining the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit may include: determining the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit based on the size of the HARQ-ACK / NACK codebook configured by the base station.

[0023] The step of determining the position of HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook may include: obtaining the minimum number of bits that HARQ-ACK / NACK can occupy for each HARQ process by dividing the size of the determined HARQ-ACK / NACK codebook by the total number of HARQ processes that can be supported in an uplink time unit; and obtaining the starting point of HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook by multiplying the minimum number of bits that HARQ-ACK / NACK can occupy for each HARQ process by the ID (identifier) ​​of the HARQ process for each downlink time unit corresponding to the uplink time unit.

[0024] The steps for generating the HARQ-ACK / NACK codebook may include: for a valid HARQ process, generating a HARQ-ACK / NACK based on the received PDSCH, and inserting the HARQ-ACK / NACK generated for the valid HARQ process into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the downlink time unit corresponding to the valid HARQ process; for an invalid HARQ process, generating a HARQ-NACK according to predefined rules, and inserting the HARQ-NACK generated for the invalid HARQ process into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the downlink time unit corresponding to the invalid HARQ process.

[0025] A valid HARQ process can refer to a HARQ process that receives a PDSCH in the downlink time unit corresponding to the uplink time unit and feeds back a HARQ-ACK / NACK for the PDSCH in the uplink time unit. An invalid HARQ process can refer to a HARQ process that does not receive a PDSCH in the downlink time unit corresponding to the uplink time unit and / or receives a PDSCH in the downlink time unit corresponding to the uplink time unit but does not feed back a HARQ-ACK / NACK for the PDSCH in the uplink time unit. Alternatively, a valid HARQ process can refer to a HARQ process that receives a PDSCH in the downlink time unit corresponding to the uplink time unit and the PDSCH is not received in the downlink time unit. HARQ processes where the downlink time unit containing the PDSCH is greater than or equal to the predefined minimum delay between the uplink time unit and the downlink time unit are invalid. Invalid HARQ processes can refer to HARQ processes that did not receive the PDSCH in the downlink time unit corresponding to the uplink time unit, and / or HARQ processes that received the PDSCH in the downlink time unit corresponding to the uplink time unit but whose downlink time unit and the uplink time unit have a time difference less than the predefined minimum delay, and / or HARQ processes that received the PDSCH in the downlink time unit corresponding to the uplink time unit but whose HARQ-ACK / NACK was fed back before the uplink time unit.

[0026] The step of inserting HARQ-ACK / NACK generated for a valid HARQ process into the HARQ-ACK / NACK codebook may include: when the number of bits of HARQ-ACK / NACK corresponding to a valid HARQ process is greater than the minimum number of bits that HARQ-ACK / NACK corresponding to each HARQ process can occupy, the HARQ-ACK / NACK corresponding to the valid HARQ process occupies the position of HARQ-ACK / NACK corresponding to the immediately following HARQ process, wherein the step of inserting HARQ-NACK generated for an invalid HARQ process into the HARQ-ACK / NACK codebook includes: when the position of HARQ-ACK / NACK corresponding to an invalid HARQ process is occupied by HARQ-ACK / NACK corresponding to a valid HARQ process, the number of bits of HARQ-ACK / NACK corresponding to an invalid HARQ process is determined as the difference between the minimum number of bits that HARQ-ACK / NACK corresponding to each HARQ process can occupy and the number of bits occupied by HARQ-ACK / NACK corresponding to a valid HARQ process.

[0027] The step of determining the position of the HARQ-ACK / NACK corresponding to each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook may include: calculating the downlink time unit index of each downlink time unit corresponding to the uplink time unit based on information about the timing of the HARQ-ACK / NACK, wherein the downlink time unit index of each downlink time unit corresponding to the uplink time unit represents the relative time order of each downlink time unit corresponding to the uplink time unit in the feedback window; obtaining the minimum number of bits that the HARQ-ACK / NACK corresponding to each downlink time unit can occupy by dividing the size of the HARQ-ACK / NACK codebook by the size of the feedback window; and obtaining the starting point of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook by multiplying the minimum number of bits that the HARQ-ACK / NACK corresponding to each downlink time unit corresponding to the uplink time unit by the downlink time unit index of each downlink time unit corresponding to the uplink time unit.

[0028] The step of determining the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook includes: calculating the size of the feedback window based on information about the HARQ-ACK / NACK timing, wherein the feedback window is a set of all downlink time units that may simultaneously feed back HARQ-ACK / NACK at the uplink time unit, determined by all possible values ​​of the HARQ-ACK timing; determining the downlink time unit index of each downlink time unit corresponding to the uplink time unit based on information about the HARQ-ACK / NACK timing, wherein the downlink time unit index of each downlink time unit corresponding to the uplink time unit... The downlink time unit indices of the units represent the relative time order of each downlink time unit corresponding to the uplink time unit in the feedback window; the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit is obtained by dividing the size of the HARQ-ACK / NACK codebook by the size of the feedback window; the starting point of HARQ-ACK / NACK for each downlink time unit corresponding to the uplink time unit is obtained by multiplying the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit corresponding to the uplink time unit by the downlink time unit index of each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook.

[0029] The control signaling may further include information indicating time units in which PDSCH will definitely not be sent. The step of calculating the size of the feedback window includes: subtracting the number of time units in which PDSCH will definitely not be sent from the calculated size of the feedback window to calculate the size of the feedback window; or, if the information indicating the time units in which PDSCH will definitely not be sent is indicated by dynamic signaling, then the calculated size of the feedback window is maintained; if the information indicating the time units in which PDSCH will definitely not be sent is indicated by semi-static signaling, then the size of the feedback window is calculated by subtracting the number of time units in which PDSCH will definitely not be sent from the calculated size of the feedback window.

[0030] The steps for generating the HARQ-ACK / NACK codebook may include: for valid downlink time units, generating HARQ-ACK / NACK based on the received PDSCH, and inserting the HARQ-ACK / NACK generated for the valid downlink time unit into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the valid downlink time unit; for invalid downlink time units, generating HARQ-NACK according to predefined rules, and inserting the HARQ-ACK / NACK generated for the invalid downlink time unit into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the invalid downlink time unit. Alternatively, for downlink time units that have not received a PDSCH, a HARQ-ACK / NACK is generated according to predefined rules, and the generated HARQ-ACK / NACK is inserted into the HARQ-ACK / NACK code book based on the position of the HARQ-ACK / NACK corresponding to the downlink time unit that has not received a PDSCH. For downlink time units that have received a PDSCH but whose corresponding HARQ-ACK / NACK is not the uplink time unit, a HARQ-ACK / NACK is generated according to the PDSCH, and the generated HARQ-ACK / NACK is inserted into the HARQ-ACK / NACK code book.

[0031] A valid downlink time unit can refer to a downlink time unit in which a PDSCH is received and the corresponding HARQ-ACK / NACK is a downlink time unit of the uplink time unit. An invalid downlink time unit can refer to a downlink time unit in which a PDSCH is not received or a downlink time unit in which a PDSCH is received but the corresponding HARQ-ACK / NACK is not a downlink time unit of the uplink time unit.

[0032] The step of inserting HARQ-ACK / NACK generated for a valid downlink time unit into the HARQ-ACK / NACK codebook may include: when the number of bits of HARQ-ACK / NACK corresponding to a valid downlink time unit is greater than the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit, the HARQ-ACK / NACK corresponding to the valid downlink time unit occupies the position of the HARQ-ACK / NACK corresponding to the immediately following downlink time unit. The step of inserting HARQ-NACK generated for an invalid downlink time unit into the HARQ-ACK / NACK codebook may include: when the position of HARQ-ACK / NACK corresponding to an invalid downlink time unit is occupied by HARQ-ACK / NACK corresponding to a valid downlink time unit, the number of bits of HARQ-ACK / NACK corresponding to the invalid downlink time unit is determined as the difference between the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit and the number of bits occupied by HARQ-ACK / NACK corresponding to the valid downlink time unit.

[0033] The step of determining the position of HARQ-ACK / NACK corresponding to each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook may include: determining the position of HARQ-ACK / NACK corresponding to each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook based on the value of the first type DAI of all scheduled downlink time units corresponding to the uplink time unit.

[0034] The steps for generating the HARQ-ACK / NACK codebook may include: starting from the beginning of the HARQ-ACK / NACK codebook, sequentially inserting HARQ-ACK / NACK corresponding to all scheduled downlink time units according to the relative time order indicated by the first type of DAI corresponding to the uplink time unit, and inserting placeholder bits at subsequent positions.

[0035] The step of sending the HARQ-ACK / NACK codebook may include: when the total number of uplink control signaling bits that need to be fed back in the uplink time unit, including at least HARQ-ACK / NACK, exceeds the maximum number of uplink control signaling bits that the PUCCH resources configured by the base station can carry, one of the following operations is performed: compressing the bits of HARQ-ACK / NACK that need to be fed back in the uplink time unit according to a predefined rule; using the next larger PUCCH resource that can carry the total number of uplink control signaling bits that need to be fed back to send the uplink control signaling in the uplink time unit; in the current downlink time unit or at least the last downlink time unit corresponding to the uplink time unit, receiving downlink scheduling information from the base station indicating a new PUCCH resource that can carry the total number of uplink control signaling bits that need to be fed back, and using the new PUCCH resource to send the uplink control signaling in the uplink time unit; abandoning the transmission of HARQ-ACK / NACK for low-priority downlink time units, so that the total number of uplink control signaling bits transmitted does not exceed the maximum number of uplink control signaling bits that the PUCCH resources configured by the base station can carry.

[0036] According to another aspect of the present invention, a downlink transmission method is provided, comprising: a base station configuring control signaling; the base station sending a PDSCH and control signaling to a user equipment in a downlink time unit, wherein the control signaling is used to determine at least one of the following for the user equipment to feed back: an uplink time unit corresponding to the PDSCH for HARQ-ACK / NACK, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the position of the HARQ-ACK / NACK corresponding to each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook.

[0037] According to another aspect of the present invention, an apparatus for transmitting HARQ-ACK / NACK is provided, comprising: a receiving unit for receiving PDSCH and control signaling from a base station in a downlink time unit; a determining unit for determining, based on the control signaling, an uplink time unit for feeding back HARQ-ACK / NACK corresponding to the received PDSCH, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook; a generating unit for generating the HARQ-ACK / NACK codebook based on the size of the HARQ-ACK / NACK codebook and the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook; and a transmitting unit for transmitting the HARQ-ACK / NACK codebook in the uplink time unit.

[0038] The control signaling may be downlink scheduling signaling carried by PDCCH or control signaling carried by PDSCH.

[0039] The control signaling may include information about HARQ-ACK / NACK timing.

[0040] Information regarding HARQ-ACK / NACK timing can be one of the following: information indicating the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback; information indicating one or more uplink time units containing configured PUCCHs that are greater than or equal to the minimum time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback, and are closest to that minimum time difference; information indicating whether the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback is predefined, or whether the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback is predefined, and is closest to one or more uplink time units containing configured PUCCHs.

[0041] The control signaling may further include a first type of DAI, wherein the first type of DAI indicates one of the following information: the relative time order of the currently scheduled downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the bit position of the HARQ-ACK / NACK bit of the currently scheduled downlink time unit in the HARQ-ACK / NACK codebook.

[0042] In the control signaling, the first type of DAI can be co-encoded with information about HARQ-ACK / NACK timing.

[0043] The control signaling may further include a second type of DAI, wherein the second type of DAI indicates one of the following information: the total number of downlink time units of all scheduled downlink time units corresponding to the uplink time unit, the total number of downlink time units from the first downlink time unit to the current downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the total number of bits of the HARQ-ACK / NACK codebook indicated by the second type of DAI.

[0044] In the control signaling, the first type DAI, the second type DAI, and information about HARQ-ACK / NACK timing can be jointly encoded.

[0045] The determining unit can calculate the size of the feedback window based on information about the HARQ-ACK / NACK timing. The feedback window is the set of all downlink time units that may simultaneously feed back HARQ-ACK / NACK in the uplink time unit, determined by all possible values ​​of the HARQ-ACK timing. By combining the size of the feedback window with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit is obtained.

[0046] The determining unit may perform one of the following steps: determining the size of the HARQ-ACK / NACK codebook by combining the maximum value of the first type DAI of all scheduled downlink time units corresponding to the uplink time unit with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit; determining the size of the HARQ-ACK / NACK codebook by combining the value of the second type DAI with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit when the second type DAI indicates the total number of downlink time units of all scheduled downlink time units corresponding to the uplink time unit; and determining the size of the HARQ-ACK / NACK codebook by combining the value of the second type DAI with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit; and determining the size of the HARQ-ACK / NACK codebook by combining the value of the second type DAI with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit. When the total number of downlink time units from the first downlink time unit to the current downlink time unit among all scheduled downlink time units corresponding to the uplink time unit is indicated, the size of the HARQ-ACK / NACK codebook is determined by combining the maximum value in the second type DAI of all scheduled downlink time units corresponding to the uplink time unit with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit; when the second type DAI indicates the total number of bits in the HARQ-ACK / NACK codebook, the size of the HARQ-ACK / NACK codebook is determined based on the number of bits indicated by the second type DAI.

[0047] The number of HARQ-ACK / NACK bits corresponding to each downlink time unit can be predefined by the standard or semi-statically configured. The number of HARQ-ACK / NACK bits corresponding to each downlink time unit is determined according to one of the following: the maximum number of transport blocks that can be sent in each downlink time unit, the maximum number of coded blocks that can be sent in each downlink time unit, and the maximum number of coded block groups that can be sent in each downlink time unit.

[0048] The control signaling may further include information indicating that the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on the maximum number of transport blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded block groups that can be transmitted in each downlink time unit.

[0049] The control signaling may also include the size of the HARQ-ACK / NACK codebook configured by the base station.

[0050] The determining unit can determine the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit based on the size of the HARQ-ACK / NACK codebook configured by the base station.

[0051] The determining unit can obtain the minimum number of bits that HARQ-ACK / NACK can occupy for each HARQ process by dividing the size of the determined HARQ-ACK / NACK codebook by the total number of HARQ processes that can be supported in an uplink time unit; and obtain the starting point of HARQ-ACK / NACK for each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook by multiplying the minimum number of bits that HARQ-ACK / NACK can occupy for each HARQ process by the ID of the HARQ process for each downlink time unit corresponding to the uplink time unit.

[0052] The generation unit can generate HARQ-ACK / NACK based on the received PDSCH for a valid HARQ process, and insert the HARQ-ACK / NACK generated for the valid HARQ process into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the downlink time unit of the valid HARQ process. For an invalid HARQ process, it can generate HARQ-NACK according to predefined rules, and insert the HARQ-NACK generated for the invalid HARQ process into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the downlink time unit of the invalid HARQ process.

[0053] A valid HARQ process can refer to a HARQ process that receives a PDSCH in the downlink time unit corresponding to the uplink time unit and feeds back a HARQ-ACK / NACK for the PDSCH in the uplink time unit. An invalid HARQ process can refer to a HARQ process that does not receive a PDSCH in the downlink time unit corresponding to the uplink time unit and / or receives a PDSCH in the downlink time unit corresponding to the uplink time unit but does not feed back a HARQ-ACK / NACK for the PDSCH in the uplink time unit. Alternatively, a valid HARQ process can refer to a HARQ process that receives a PDSCH in the downlink time unit corresponding to the uplink time unit and the PDSCH is not received in the downlink time unit. HARQ processes where the downlink time unit containing the PDSCH is greater than or equal to the predefined minimum delay between the uplink time unit and the downlink time unit are invalid. Invalid HARQ processes can refer to HARQ processes that did not receive the PDSCH in the downlink time unit corresponding to the uplink time unit, and / or HARQ processes that received the PDSCH in the downlink time unit corresponding to the uplink time unit but whose downlink time unit and the uplink time unit have a time difference less than the predefined minimum delay, and / or HARQ processes that received the PDSCH in the downlink time unit corresponding to the uplink time unit but whose HARQ-ACK / NACK was fed back before the uplink time unit.

[0054] The generating unit may, when the number of bits of HARQ-ACK / NACK corresponding to a valid HARQ process is greater than the minimum number of bits that HARQ-ACK / NACK can occupy for each HARQ process, occupy the positions of HARQ-ACK / NACK corresponding to the valid HARQ process and the HARQ-ACK / NACK corresponding to the immediately following HARQ process. The step of inserting HARQ-NACK generated for an invalid HARQ process into the HARQ-ACK / NACK codebook includes: when the position of HARQ-ACK / NACK corresponding to an invalid HARQ process is occupied by HARQ-ACK / NACK corresponding to a valid HARQ process, determining the number of bits of HARQ-ACK / NACK corresponding to an invalid HARQ process as the difference between the minimum number of bits that HARQ-ACK / NACK can occupy for each HARQ process and the number of bits occupied by HARQ-ACK / NACK corresponding to a valid HARQ process.

[0055] The determining unit can calculate the downlink time unit index of each downlink time unit corresponding to the uplink time unit based on information about HARQ-ACK / NACK timing, wherein the downlink time unit index of each downlink time unit corresponding to the uplink time unit represents the relative time order of each downlink time unit corresponding to the uplink time unit in the feedback window; the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit is obtained by dividing the size of the HARQ-ACK / NACK codebook by the size of the feedback window; the starting point of HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook is obtained by multiplying the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit corresponding to the uplink time unit by the downlink time unit index of each downlink time unit corresponding to the uplink time unit.

[0056] The determining unit can calculate the size of the feedback window based on information about the HARQ-ACK / NACK timing. The feedback window is a set of all downlink time units that may simultaneously feed back HARQ-ACK / NACK at the uplink time unit, determined by all possible values ​​of the HARQ-ACK timing. Based on the HARQ-ACK / NACK timing information, the determining unit can determine the downlink time unit index for each downlink time unit corresponding to the uplink time unit. The downlink time unit index for each downlink time unit corresponding to the uplink time unit represents the index of each downlink time unit corresponding to the uplink time unit. The relative time order of time units in the feedback window; the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit is obtained by dividing the size of the HARQ-ACK / NACK codebook by the size of the feedback window; the starting point of HARQ-ACK / NACK for each downlink time unit corresponding to the uplink time unit is obtained by multiplying the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit corresponding to the uplink time unit by the downlink time unit index of each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook.

[0057] The control signaling may further include information indicating time units in which PDSCH will definitely not be sent. The step of calculating the size of the feedback window includes: subtracting the number of time units in which PDSCH will definitely not be sent from the calculated size of the feedback window to calculate the size of the feedback window; or, if the information indicating the time units in which PDSCH will definitely not be sent is indicated by dynamic signaling, then the calculated size of the feedback window is maintained; if the information indicating the time units in which PDSCH will definitely not be sent is indicated by semi-static signaling, then the size of the feedback window is calculated by subtracting the number of time units in which PDSCH will definitely not be sent from the calculated size of the feedback window.

[0058] The generation unit can generate HARQ-ACK / NACK for valid downlink time units based on the received PDSCH, and insert the generated HARQ-ACK / NACK for the valid downlink time unit into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the valid downlink time unit; for invalid downlink time units, it can generate HARQ-NACK according to predefined rules, and insert the generated HARQ-NACK for the invalid downlink time unit into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the invalid downlink time unit. Alternatively, for downlink time units that have not received a PDSCH, HARQ-NACK is generated according to predefined rules, and the generated HARQ-NACK is inserted into the HARQ-ACK / NACK code book based on the position of the HARQ-ACK / NACK corresponding to the downlink time unit that has not received a PDSCH. For downlink time units that have received a PDSCH but whose corresponding HARQ-ACK / NACK is not the uplink time unit, HARQ-ACK / NACK is generated according to the PDSCH, and the generated HARQ-ACK / NACK is inserted into the HARQ-ACK / NACK code book.

[0059] A valid downlink time unit can refer to a downlink time unit in which a PDSCH is received and the corresponding HARQ-ACK / NACK is a downlink time unit of the uplink time unit. An invalid downlink time unit can refer to a downlink time unit in which a PDSCH is not received or a downlink time unit in which a PDSCH is received but the corresponding HARQ-ACK / NACK is not a downlink time unit of the uplink time unit.

[0060] When the number of HARQ-ACK / NACK bits corresponding to a valid downlink time unit is greater than the minimum number of bits that can be occupied by HARQ-ACK / NACK for each downlink time unit, the generating unit will occupy the position of HARQ-ACK / NACK for the valid downlink time unit and the position of HARQ-ACK / NACK for the immediately following downlink time unit. When the position of HARQ-ACK / NACK for an invalid downlink time unit is occupied by HARQ-ACK / NACK for a valid downlink time unit, the generating unit will determine the number of HARQ-ACK / NACK bits corresponding to the invalid downlink time unit as the difference between the minimum number of bits that can be occupied by HARQ-ACK / NACK for each downlink time unit and the number of bits occupied by HARQ-ACK / NACK for the valid downlink time unit.

[0061] The determining unit can determine the position of HARQ-ACK / NACK in the HARQ-ACK / NACK codebook for each downlink time unit corresponding to the uplink time unit based on the value of the first type DAI of all scheduled downlink time units corresponding to the uplink time unit.

[0062] The generating unit can start from the beginning of the HARQ-ACK / NACK codebook, and sequentially insert HARQ-ACK / NACK corresponding to all scheduled downlink time units according to the relative time order indicated by the first type DAI of all scheduled downlink time units corresponding to the uplink time unit, and insert placeholder bits in subsequent positions.

[0063] When generating the HARQ-ACK / NACK codebook, if at least two PDSCHs correspond to the same transport block within the same HARQ-ACK / NACK codebook, then when the user terminal generates the HARQ-ACK / NACK for the PDSCH, for the same transport block, the HARQ-ACK / NACK of the last PDSCH in chronological order will generate HARQ-ACK / NACK bits based on the decoding result of the PDSCH, while setting the HARQ-ACK / NACK bit values ​​of all coded block groups of the preceding PDSCHs to predefined values; or, for the same transport block, the user terminal will set the HARQ-ACK / NACK values ​​of all received PDSCHs to the same value, which is generated based on the demodulation result of the last received PDSCH.

[0064] When the total number of uplink control signaling bits that need to be fed back in the uplink time unit exceeds the maximum number of uplink control signaling bits that the PUCCH resources configured by the base station can carry, the transmitting unit may perform one of the following operations: compress the bits of HARQ-ACK / NACK that need to be fed back in the uplink time unit according to a predefined rule; use the next larger PUCCH resource that can carry the total number of uplink control signaling bits that need to be fed back to transmit the uplink control signaling in the uplink time unit; in the current downlink time unit or at least the last downlink time unit corresponding to the uplink time unit, receive downlink scheduling information from the base station indicating a new PUCCH resource that can carry the total number of uplink control signaling bits that need to be fed back, and use the new PUCCH resource to transmit the uplink control signaling in the uplink time unit; abandon the transmission of HARQ-ACK / NACK in low-priority downlink time units, so that the total number of uplink control signaling bits transmitted does not exceed the maximum number of uplink control signaling bits that the PUCCH resources configured by the base station can carry.

[0065] According to another aspect of the present invention, a downlink transmission device is provided, comprising: a configuration unit for configuring control signaling; and a transmission unit for transmitting PDSCH and control signaling to a user equipment in a downlink time unit, wherein the control signaling is used to determine for the user equipment to feed back at least one of the following: an uplink time unit corresponding to HARQ-ACK / NACK of the PDSCH, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the position of the HARQ-ACK / NACK corresponding to each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook.

[0066] According to the present invention, when the HARQ-ACK feedback time is variable, the user equipment can accurately determine the size of the HARQ-ACK codebook and the bit mapping, while ensuring the effective utilization of uplink control channel resources. Attached Figure Description

[0067] These and / or other aspects and advantages of the invention will become clear and more readily understood from the following description of the embodiments, taken in conjunction with the accompanying drawings, wherein:

[0068] Figure 1 This is a flowchart of the method for sending HARQ-ACK / NACK according to the present invention;

[0069] Figure 2 This is a schematic diagram of a HARQ process according to a first exemplary embodiment of the present invention;

[0070] Figure 3 This is a schematic diagram of uplink and downlink mapping based on a HARQ process according to a first exemplary embodiment of the present invention;

[0071] Figure 4 This is a schematic diagram illustrating the generation of HARQ-ACK / NACK based on a HARQ process according to a first exemplary embodiment of the present invention;

[0072] Figure 5 This is another schematic diagram of generating HARQ-ACK / NACK based on the HARQ process according to a first exemplary embodiment of the present invention;

[0073] Figure 6 This is a schematic diagram of uplink and downlink mapping based on downlink time units according to a first exemplary embodiment of the present invention;

[0074] Figure 7 This is a schematic diagram of generating HARQ-ACK / NACK based on a downlink time unit according to a first exemplary embodiment of the present invention;

[0075] Figure 8 This is a schematic diagram of uplink and downlink mapping based on downlink time units according to a second exemplary embodiment of the present invention;

[0076] Figure 9 This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a second exemplary embodiment of the present invention;

[0077] Figure 10 This is a schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention;

[0078] Figure 11 This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention;

[0079] Figure 12 This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention;

[0080] Figure 13 This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention;

[0081] Figure 14 This is a flowchart of the downlink transmission method according to the present invention;

[0082] Figure 15 This is a block diagram of a device for transmitting HARQ-ACK / NACK according to the present invention;

[0083] Figure 16This is a block diagram of a downlink transmission device according to the present invention;

[0084] Figure 17 This is a schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention;

[0085] Figure 18 This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention. Detailed Implementation

[0086] The following description, provided with reference to the accompanying drawings, is intended to aid in a full understanding of embodiments of the invention as defined by the claims and their equivalents. Various specific details are included to aid understanding, but these details are to be considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Furthermore, for clarity and brevity, descriptions of well-known functions and structures are omitted.

[0087] Figure 1 This is a flowchart of the method for sending HARQ-ACK / NACK according to the present invention. The following will refer to... Figure 1 This describes a method for sending HARQ-ACK / NACK by a user equipment according to an exemplary embodiment of the present invention.

[0088] First, in step 101, the user equipment receives PDSCH and control signaling from the base station in the downlink time unit.

[0089] The control signaling described herein is downlink scheduling signaling carried via PDCCH or control signaling carried via PDSCH. The control signaling may include information regarding HARQ-ACK / NACK timing.

[0090] According to an exemplary embodiment, information regarding HARQ-ACK / NACK timing can be indicated by dynamic signaling or semi-static signaling. For example, it can be indicated by downlink control signaling (DCI) carried by the PDCCH, or by higher-layer control signaling carried by the PDSCH, or by a combination of both.

[0091] According to an exemplary embodiment, the number of bits for information regarding HARQ-ACK / NACK timing can be predefined by the standard or configured semi-statically by the base station. For example, the standard predefines the number of bits for information regarding HARQ-ACK / NACK timing to 2 bits, or the higher-layer signaling configures the time difference k between ACK / NACK feedback and PDSCH reception. iLet i = 0, 1, 2... In DCI, 2 bits are used to indicate the timing of HARQ-ACK / NACK, which can indicate one of the four time differences i = 0, 1, 2, 3. Base stations can configure different k values ​​for different service types or different DCIs. i The number of bits can be configured differently. For example, in the common search area of ​​the downlink control channel (PDCCH), the number of bits for the HARQ-ACK / NACK timing information of the DCI is 0 bits, and the HARQ-ACK / NACK timing value is a fixed value predefined by the standard. In the user-dedicated search area of ​​the downlink control channel (PDCCH), the number of bits for the HARQ-ACK / NACK timing information of the DCI is 2 bits, and the HARQ-ACK / NACK timing value is a set of values ​​configured by the higher layer or predefined by the standard. Alternatively, the number of bits for the HARQ-ACK / NACK timing information of a certain type or class of DCI can be defined as 0 bits, and the HARQ-ACK / NACK timing value is predefined by the standard, while the number of bits for the HARQ-ACK / NACK timing information of other types of DCI is 2 bits, and the HARQ-ACK / NACK timing value is a set of values ​​configured by the higher layer or predefined by the standard.

[0092] According to an exemplary embodiment, information regarding HARQ-ACK / NACK timing can indicate the time difference between the downlink time unit where the PDSCH is located and the uplink time unit for the feedback HARQ-ACK / NACK. For example, if the downlink time unit where the PDSCH is located is n, and the corresponding uplink time unit for the feedback HARQ-ACK / NACK is m, the information regarding HARQ-ACK / NACK timing can indicate mn.

[0093] According to an exemplary embodiment, the time difference between the downlink time unit where the PDSCH is located and the uplink time unit corresponding to the feedback HARQ-ACK / NACK is the sum of the information regarding the HARQ-ACK / NACK timing and the time difference offset k0. For example, if the information regarding the HARQ-ACK / NACK timing is 2 bits, the downlink time unit where the PDSCH is located is n, and the corresponding uplink time unit for the feedback HARQ-ACK / NACK is m, then the time difference mn between the downlink time unit where the PDSCH is located and the uplink time unit corresponding to the feedback HARQ-ACK / NACK can be k0+0, k0+1, ..., k0+3.

[0094] Here, the time difference offset k is either predefined by the standard or configured by higher layers. Different HARQ-ACK / NACK timing values ​​and / or k0 values ​​can be predefined based on different service types or different DCIs. Preferably, different HARQ-ACK / NACK timing values ​​and / or k0 values ​​are predefined for different DCIs. For example, the HARQ-ACK / NACK timing values ​​and / or k0 of DCIs within the common search area of ​​the downlink control channel (PDCCH) can be one or a set of predefined values ​​by the standard, while the HARQ-ACK / NACK timing values ​​and / or k0 of DCIs within the user-specific search area of ​​the PDCCH can be one or a set of values ​​configured by higher layers. Alternatively, for a certain type or class of DCIs, the HARQ-ACK / NACK timing values ​​and / or k0 can be one or a set of predefined values ​​by the standard, while for other types of DCIs, the HARQ-ACK / NACK timing values ​​and / or k0 can be one or a set of values ​​configured by higher layers. Alternatively, the standard can predefine multiple sets of HARQ-ACK / NACK timing values ​​and / or k0 values, for example, predefining multiple sets of values ​​for UEs with different processing capabilities, and the base station can semi-statically indicate which set of HARQ-ACK / NACK timing values ​​to use. For TDD systems, the standard-predefined HARQ-ACK / NACK timing can assume that the uplink time unit m0 corresponding to the ACK / NACK of the downlink time unit n determined according to the TDD configuration is the next or several available uplink time units m0. i One of (i>0). Since the uplink time units in a TDD system are often discrete, directly indicating the absolute time difference between the uplink time unit of the ACK / NACK feedback and the downlink reception via DCI would require a large bit overhead. Therefore, the uplink unit of the ACK / NACK feedback can be determined by combining the uplink and downlink information of TDD. The uplink time units m0 to m10 determined based on the uplink and downlink information of TDD are... iThe uplink / downlink ratio can be determined based on the semi-statically configured TDD uplink / downlink ratio, or it can be determined based on the uplink / downlink ratio information received by dynamic signaling. For example, if the user equipment receives an uplink / downlink time slot indication of DSUDDDSUDD in downlink time unit n, and receives an uplink / downlink time slot indication of DSUUU in downlink time unit n+8, then, assuming that 2 bits still indicate the ACK / NACK feedback time, if the UE receives DCI in downlink time unit n, the 2 bits represent uplink time units n+7, n+10, n+11, and n+12, respectively. Here, n+7 is the first uplink time unit that satisfies the minimum ACK / NACK feedback delay, and n+10, n+11, and n+12 are the most recent 2nd, 3rd, and 4th available uplink time units, respectively.

[0095] According to an exemplary embodiment, higher-layer signaling configures uplink time units capable of transmitting PUCCH. For example, a period and time offset are configured to determine the uplink time units capable of transmitting PUCCH. In this case, information regarding HARQ-ACK / NACK timing indicates one or more of the configured PUCCH uplink time units that are greater than or equal to the minimum time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides feedback HARQ-ACK / NACK, and that are closest to that minimum time difference. Here, the minimum time difference can be a fixed value, or it can be a different value for different service types, or it can be a different value for different UE processing capabilities. For example, when the period of the uplink time unit is N1, the uplink time unit n satisfies n mod N1 = 0. When the information regarding HARQ-ACK / NACK timing is 2 bits, it indicates the first, second, third, and fourth uplink time units configured according to the period that are greater than or equal to the minimum time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides feedback HARQ-ACK / NACK, and that are closest to that minimum time difference.

[0096] According to an exemplary embodiment, when the base station is semi-statically configured with uplink time units capable of transmitting PUCCH, the information regarding HARQ-ACK / NACK timing further indicates whether it is the time difference between the predefined downlink time unit where the PDSCH is located and the uplink time unit that provides HARQ-ACK / NACK feedback, or whether it is greater than or equal to the time difference between the predefined downlink time unit where the PDSCH is located and the uplink time unit that provides HARQ-ACK / NACK feedback, and is closest to one or more of the configured uplink time units. For example, the predefined HARQ-ACK / NACK timing for PDSCH and ACK / NACK feedback is 3 time units; for instance, the PDSCH is received in downlink time unit n, and ACK / NACK is provided in uplink time unit n+3. The semi-statically configured uplink time units satisfy n mod N1 = 0, where N1 represents the period of the semi-statically configured uplink time units. Therefore, one bit in the DCI of the PDSCH for downlink time unit n can indicate whether ACK / NACK is fed back in uplink time unit n+3 or uplink time unit n+N, where N>=3 and (n+N)mod N1=0. In a semi-static uplink time unit, the ACK / NACK codebook size can be determined based on N1 downlink time units. However, in a non-semi-static uplink time unit, the codebook size is determined based on one downlink time unit.

[0097] Preferably, the control signaling may further include indication information of the HARQ-ACK / NACK codebook size.

[0098] According to an exemplary embodiment, the base station is configured with a codebook size for HARQ-ACK / NACK.

[0099] According to an exemplary embodiment, the base station configures the total number of HARQ processes, or a standard predefined number. Furthermore, the base station configures the number of HARQ-ACK / NACK bits for each HARQ process, or a standard predefined number. The HARQ-ACK / NACK codebook size is determined based on the total number of HARQ processes and the number of HARQ-ACK / NACK bits for each HARQ process.

[0100] According to an exemplary embodiment, the base station configures a HARQ-ACK / NACK feedback window, or the HARQ-ACK / NACK feedback window is predefined by a standard. Here, the HARQ-ACK / NACK feedback window is a set of all downlink time units that may simultaneously feed back HARQ-ACK / NACK in the uplink time unit, determined by all possible values ​​of the HARQ-ACK timing. Furthermore, the base station semi-statically configures the number of HARQ-ACK / NACK bits for each downlink time unit within the HARQ-ACK / NACK feedback window, or the number of HARQ-ACK / NACK bits for each downlink time unit is predefined by a standard. Therefore, the HARQ-ACK / NACK codebook size is determined based on the HARQ-ACK / NACK feedback window size and the number of HARQ-ACK / NACK bits for each downlink time unit within the feedback window. Here, the number of HARQ-ACK / NACK bits corresponding to each downlink time unit can be determined based on one of the following: the maximum number of transport blocks that can be transmitted in each downlink time unit, the maximum number of coded blocks that can be transmitted in each downlink time unit, or the maximum number of coded block groups that can be transmitted in each downlink time unit. Here, the control signaling may include information indicating that the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on the maximum number of transport blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded block groups that can be transmitted in each downlink time unit.

[0101] Preferably, when the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is configured according to the maximum number of coded block groups that can be sent in each downlink time unit, the HARQ-ACK / NACK bits are determined according to the number of coded block groups, regardless of whether the downlink time unit is scheduled using transport block-based scheduling signaling or coded block group-based scheduling signaling.

[0102] Preferably, the control signaling may further include a first type of DAI, wherein the first type of DAI indicates one of the following information: the relative time order of the currently scheduled downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the bit position of the HARQ-ACK / NACK bit of the currently scheduled downlink time unit in the HARQ-ACK / NACK codebook. The user equipment may also determine the size of the HARQ-ACK / NACK codebook corresponding to each uplink time unit and the position of the HARQ-ACK / NACK bit corresponding to each downlink time unit in the HARQ-ACK / NACK codebook based on the first type of DAI. Here, the size of the HARQ-ACK / NACK codebook corresponding to each uplink time unit determined by the first type of DAI is variable, thereby ensuring that the resources of the uplink control channel are effectively utilized.

[0103] According to a preferred embodiment of the present invention, in the control signaling, the first type of DAI can be jointly encoded with information regarding HARQ-ACK / NACK timing. This compresses the bits of the downlink control signaling, thereby ensuring efficient utilization of the downlink control channel resources.

[0104] Preferably, the control signaling may further include a second type of DAI. Here, the second type of DAI indicates one of the following: the total number of downlink time units among all scheduled downlink time units corresponding to the uplink time unit; the total number of downlink time units from the first downlink time unit to the current downlink time unit among all scheduled downlink time units corresponding to the uplink time unit; or the total number of bits in the HARQ-ACK / NACK codebook indicated by the second type of DAI. The user equipment can use the second type of DAI to determine the size of the HARQ-ACK / NACK codebook corresponding to each uplink time unit. Here, the size of the HARQ-ACK / NACK codebook corresponding to each uplink time unit determined by the second type of DAI is variable, thereby ensuring that the resources of the uplink control channel are effectively utilized.

[0105] According to a preferred embodiment of the present invention, in the control signaling, the first type DAI, the second type DAI, and information regarding HARQ-ACK / NACK timing can be jointly encoded. This compresses the bits of the downlink control signaling, thereby ensuring efficient utilization of the downlink control channel resources.

[0106] Preferably, the control signaling may include a third type of DAI, wherein the content indicated by the third type of DAI is the same as the content indicated by the second type of DAI, or the third type of DAI indicates the total number of bits of the HARQ-ACK / NACK codebook that the base station expects to receive, and the total number of HARQ-ACK / NACK bits corresponding to the PDSCH actually scheduled by the base station is less than or equal to the expected total number of bits. The control signaling containing the first type of DAI and / or the second type of DAI and the control signaling containing the third type of DAI may be independent signaling, for example, one is scheduling the downlink transmission of DCI and the other is scheduling the uplink transmission of DCI.

[0107] The preferred embodiments described above will now be described in detail with reference to exemplary embodiments of the present invention. (Return to Reference) Figure 1 Then, in step 102, the user equipment, based on the control signaling, determines the uplink time unit for feeding back the HARQ-ACK / NACK corresponding to the received PDSCH, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook. Subsequently, it will refer to... Figures 2-13 The specific implementation method of this step is described in detail.

[0108] Next, in step 103, based on the size of the HARQ-ACK / NACK codebook and the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook, a HARQ-ACK / NACK codebook is generated. Subsequently, it will be referred to... Figures 2-13 The specific implementation method of this step is described in detail.

[0109] Finally, in step 104, the HARQ-ACK / NACK codebook generated in step S107 is sent in the uplink time unit.

[0110] The following will describe a first exemplary embodiment of the present invention. .

[0111] In a first exemplary embodiment, the control signaling received by the user equipment from the base station may further include the size of the HARQ-ACK / NACK codebook configured by the base station.

[0112] Therefore, in step 103, the user equipment can determine the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit based on the size of the HARQ-ACK / NACK codebook configured by the base station.

[0113] According to one aspect of the first exemplary embodiment, the control signaling further includes the total number of HARQ processes that can be supported in an uplink time unit and the HARQ process ID, or the control signaling further includes the HARQ process ID, and the total number of HARQ processes that can be supported in an uplink time unit is predefined by the standard. Therefore, the user equipment can generate a HARQ-ACK / NACK codebook corresponding to the uplink time unit based on the HARQ process.

[0114] Reference Figure 2 , Figure 2 This is a schematic diagram of HARQ processing according to a first exemplary embodiment of the present invention. Figure 2 In the example, it is assumed that the total number of HARQ processes that can be supported in an uplink time unit is 8. Here, the total number of HARQ processes that can be supported in an uplink time unit may be included in the control signaling, or it may be predefined by the standard. The HARQ-ACK / NACK corresponding to each HARQ process that receives PDSCH in the downlink time unit can be mapped to the HARQ-ACK / NACK codebook for that uplink time unit, such as... Figure 3 As shown.

[0115] Therefore, in step 102, the user equipment can determine the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook based on the size of the HARQ-ACK / NACK codebook, the total number of HARQ processes that can be supported in an uplink time unit, and the ID of each HARQ process.

[0116] Specifically, the minimum number of bits Y that can be occupied by each HARQ process is obtained by dividing the size X of the determined HARQ-ACK / NACK codebook by the total number L of HARQ processes that can be supported in one uplink time unit, i.e., Y = (X / L).

[0117] Then, by multiplying the minimum number of bits that HARQ-ACK / NACK can occupy for each HARQ process by the ID i of the HARQ process for each downlink time unit corresponding to the uplink time unit, for example, i = 0, 1, ..., L-1, the starting point Y*i, i = 0, 1, ..., L-1 of the HARQ-ACK / NACK corresponding to each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook is obtained.

[0118] In step 103, the user equipment can generate HARQ-ACK / NACK based on the HARQ process. Here, the HARQ process can be divided into valid HARQ processes and invalid HARQ processes. A valid HARQ process refers to a HARQ process that receives a PDSCH in the downlink time unit corresponding to the uplink time unit, and the time difference between the uplink time unit and the downlink time unit where the PDSCH is located is greater than or equal to a predefined minimum delay. An invalid HARQ process refers to a HARQ process that does not receive a PDSCH in the downlink time unit corresponding to the uplink time unit, and / or receives a PDSCH in the downlink time unit, but the time difference between the uplink time unit and the downlink time unit where the PDSCH is located is less than a predefined minimum delay, and / or receives a PDSCH in the downlink time unit, but the HARQ-ACK / NACK of the PDSCH has been fed back before the uplink time unit.

[0119] Preferably, a valid HARQ process refers to a HARQ process that feeds back HARQ-ACK / NACK in the uplink time unit, meaning that the UE receives the PDSCH in the downlink time unit, and the HARQ-ACK / NACK of the PDSCH is fed back in the uplink time unit. If the UE receives the PDSCH in the downlink time unit, but the HARQ-ACK / NACK of the PDSCH is not fed back in the uplink time unit, then for the uplink time unit, this HARQ process is an invalid HARQ process.

[0120] For a valid HARQ process, the user equipment generates a HARQ-ACK / NACK based on the received PDSCH, and inserts the HARQ-ACK / NACK generated for the valid HARQ process into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the downlink time unit of the valid HARQ process.

[0121] For invalid HARQ processes, the user equipment generates HARQ-NACK according to predefined rules, and inserts the HARQ-NACK generated for the invalid HARQ process into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the downlink time unit corresponding to the invalid HARQ process.

[0122] When the number of HARQ-ACK / NACK bits corresponding to a valid HARQ process exceeds the minimum number of bits that can be occupied by HARQ-ACK / NACK for each HARQ process, the user equipment will occupy the position of the HARQ-ACK / NACK corresponding to the valid HARQ process and the position of the HARQ-ACK / NACK corresponding to the immediately following HARQ process. For example, specifically, the number Z of ACK / NACK bits for a HARQ process (i.e., a valid HARQ process) receiving PDSCH in the corresponding time unit can be greater than or equal to Y. In this case, the ACK / NACK bits corresponding to the HARQ process may occupy the number of ACK / NACK bits for the immediately following HARQ process.

[0123] When the HARQ-ACK / NACK bit corresponding to an invalid HARQ process is occupied by the HARQ-ACK / NACK bit corresponding to a valid HARQ process, the user equipment determines the number of HARQ-ACK / NACK bits corresponding to the invalid HARQ process as the difference between the number of bits available for HARQ-ACK / NACK for each HARQ process and the number of bits occupied for HARQ-ACK / NACK for the valid HARQ process. For example, the number of ACK / NACK bits Z' for a HARQ process that did not receive PDSCH in the corresponding time unit (i.e., invalid HARQ processing) is determined based on whether it is occupied by the ACK / NACK bit of a valid HARQ process. If it is not occupied by the ACK / NACK bit of a valid HARQ process, then Z' = Y. If it is occupied by the ACK / NACK bit of a valid HARQ process, assuming the number of bits occupied is Y1, then Z' = Y - Y1. When Y = Y1, Z' = 0.

[0124] Therefore, according to embodiments of the present invention, in order to avoid the overlap of ACK / NACK bits of valid HARQ processes, the base station should avoid scheduling adjacent HARQ processes that feed back ACK / NACK in the same uplink time unit when performing scheduling.

[0125] Figure 4 This is a schematic diagram of HARQ-ACK / NACK generation based on a HARQ process according to a first exemplary embodiment of the present invention.

[0126] Assuming X = 16, L = 8, Y = 2, and Z = 4, the ACK / NACK codebook length is 16. If HARQ process 2 receives the PDSCH in the corresponding time unit, it generates a 4-bit ACK / NACK based on the PDSCH decoding result. If no other HARQ process receives the PDSCH in the corresponding time unit, bits 0 to 3 in the ACK / NACK codebook correspond to HARQ process 0 and HARQ process 1, respectively. Due to no scheduling, they generate Y = 2 bits of NACK. Bits 4 to 7 correspond to HARQ process 2, generating a 4-bit ACK / NACK based on the PDSCH decoding result. Bits 8 to 15 correspond to HARQ processes 4 to 7, respectively, generating Y = 2 bits of NACK due to no scheduling. It is easy to see that the 4 bits of HARQ process 2 occupy the 2-bit position of HARQ process 3.

[0127] In this example, if the base station needs to schedule other HARQ processes, it should avoid scheduling HARQ process 3. This is because the ACK / NACK bits for HARQ process 3 are already occupied by HARQ process 2. In this case, the base station can schedule, for example, HARQ process 4.

[0128] Figure 5 This is another schematic diagram of generating HARQ-ACK / NACK based on the HARQ process according to a first exemplary embodiment of the present invention.

[0129] Reference Figure 5 Assuming X = 16, L = 8, Y = 2, and Z = 4, the ACK / NACK codebook length is 16. If HARQ process 2 and HARQ process 4 receive the PDSCH in their respective time units, they generate 4 bits of ACK / NACK based on the PDSCH decoding result. If other HARQ processes do not receive the PDSCH in their respective time units, bits 0 to 3 in the ACK / NACK codebook correspond to HARQ process 0 and HARQ process 1, respectively. Due to no scheduling, they generate Y = 2 bits of NACK. Bits 4 to 7 correspond to HARQ process 2, generating 4 bits of ACK / NACK based on the PDSCH decoding result. Bits 8 to 11 correspond to HARQ process 4, generating 4 bits of ACK / NACK based on the PDSCH decoding result. Bits 12 to 15 correspond to HARQ processes 6 to 7, respectively, generating Y = 2 bits of NACK based on no scheduling. It is easy to see that the 4 bits of HARQ process 2 occupy the 2 bits of HARQ process 3, and the 4 bits of HARQ process 4 occupy the 2 bits of HARQ process 5.

[0130] In this example, if the base station needs to schedule other HARQ processes, it should avoid scheduling HARQ process 3 and HARQ process 5. This is because the ACK / NACK bits of HARQ process 3 are already occupied by HARQ process 2, and the ACK / NACK bits of HARQ process 5 are already occupied by HARQ process 4. In this case, the base station can schedule, for example, HARQ process 6.

[0131] It is worth noting that although in the above examples, the HARQ ID and the time sequence of the downlink time units are in a one-to-one correspondence, this invention also applies to situations where the HARQ ID size and the time sequence of the downlink time units are not in a one-to-one correspondence. For example, downlink time unit n is the HARQ process with HARQ ID = 6, and downlink time unit n+4 is the HARQ process with HARQ ID = 1. Therefore, when mapping the HARQ-ACK bits, the order of the HARQ IDs is still followed, that is, the HARQ-ACK bit of HARQ ID = 1 precedes the HARQ-ACK bit of HARQ ID = 6.

[0132] According to another aspect of the first exemplary embodiment, the user equipment may generate a HARQ-ACK / NACK codebook corresponding to the uplink time unit based on the downlink time unit. Therefore, the user equipment may also determine the position of the HARQ-ACK / NACK corresponding to the PDSCH of each time unit in the HARQ-ACK / NACK codebook based on the downlink time unit index.

[0133] Specifically, firstly, the user equipment determines the size of the feedback window and the downlink time unit index of each downlink time unit corresponding to the uplink time unit based on information about the HARQ-ACK / NACK timing. Here, the feedback window is a set of all downlink time units that may simultaneously feed back HARQ-ACK / NACK at the uplink time unit, determined by all possible values ​​of the HARQ-ACK timing. The downlink time unit indexes of each downlink time unit corresponding to the uplink time unit represent the relative time order of each downlink time unit corresponding to the uplink time unit within the feedback window.

[0134] For example, Figure 6 This is a schematic diagram of uplink and downlink mapping based on downlink time units according to a first exemplary embodiment of the present invention.

[0135] Reference Figure 6Assuming the feedback window size is L, the earliest time unit within the feedback window corresponds to the smallest time unit index, for example, 0, while the latest time unit corresponds to the largest time unit index, for example, L-1. The time units within the feedback window can be continuous or discontinuous. For example, if the number of bits indicating HARQ-ACK / NACK timing in the downlink control signaling (DCI) is N, then 2^N time values ​​can be indicated. That is, within the same uplink time unit, a maximum of 2^N downlink time units of PDSCH HARQ-ACK / NACK can be fed back. Therefore, the feedback window size L = 2^N. The HARQ-ACK / NACK timing values ​​indicated in the DCI can be predefined according to a standard. For example, 3 bits can indicate that the difference mn between the PDSCH time unit n and the corresponding HARQ-ACK / NACK time unit m is 0, 1, ..., 7. Then the feedback window size L = 8, and the time units within the feedback window are continuous.

[0136] For example, if there are 2 bits in the DCI indicating the HARQ-ACK / NACK timing, then the size of the feedback window L = 4. If the higher layer configures the HARQ-ACK / NACK timing indicated in the DCI (i.e., the time relationship between PDSCH and HARQ-ACK / NACK) to be 0, 2, 4, 6, then the feedback window consists of 4 time units with an interval of 2.

[0137] For example, some time units within the feedback window can be time units that do not send downlink PDSCH. For instance, in a TDD system, if the time unit is configured as an uplink time unit, then the time unit will definitely not send downlink PDSCH. Therefore, when calculating the size L of the feedback window, the time unit can be removed. Preferably, the time unit that definitely does not send PDSCH can be determined by semi-static signaling (e.g., RRC signaling) or by dynamic signaling (e.g., DCI indication). Preferably, when calculating the size L of the feedback window, the time unit that definitely does not send PDSCH can be removed regardless of the signaling used to indicate it. According to another aspect of the invention, when calculating the size L of the feedback window, if the time unit is indicated by semi-static signaling that definitely does not send PDSCH, it can be removed; however, if the time unit is indicated by dynamic signaling that definitely does not send PDSCH, it cannot be removed.

[0138] Next, the minimum number of bits that can be occupied by HARQ-ACK / NACK for each downlink time unit is obtained by dividing the size of the HARQ-ACK / NACK codebook by the size of the feedback window. For example, the minimum number of bits that can be occupied by HARQ-ACK / NACK for each downlink time unit can be determined by the base station configuring the ACK / NACK codebook size X and the feedback window size L, Y = X / L. Alternatively, the base station configures the number of bits for HARQ-ACK / NACK for each downlink time unit, for example, as described above, the configured number of bits is the maximum number of coded block groups that can be transmitted. If the base station configures the UE to dynamically switch between coded block group-based scheduling and transport block group-based scheduling, the number of bits for the UE's HARQ-ACK is always determined according to the coded block group-based scheduling, i.e., according to the maximum number of coded block groups that can be transmitted. Then, by multiplying the minimum number of bits that HARQ-ACK / NACK can occupy for each downlink time unit by the downlink time unit index corresponding to the uplink time unit, the starting point of HARQ-ACK / NACK for each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook is obtained. That is, the starting point of HARQ-ACK / NACK corresponding to downlink time unit i is Y*i, i=0,1,…L-1.

[0139] After determining the starting point of HARQ-ACK / NACK according to the above method, ACK / NACK can be inserted into the HARQ-ACK / NACK codebook for valid and invalid downlink time units. Here, a valid downlink time unit refers to a downlink time unit in which a PDSCH is received and the uplink time unit corresponding to the HARQ-ACK / NACK of that PDSCH is the uplink time unit. An invalid downlink time unit refers to a downlink time unit in which a PDSCH is not received or a downlink time unit in which a PDSCH is received but the uplink time unit corresponding to the HARQ-ACK / NACK of that PDSCH is not the uplink time unit. That is, in the downlink time unit, although a PDSCH is received, if its ACK / NACK feedback time unit is not the ACK / NACK feedback time unit, then the downlink time unit is considered invalid relative to the ACK / NACK feedback time unit.

[0140] For a valid downlink time unit, HARQ-ACK / NACK is generated based on the received PDSCH, and the HARQ-ACK / NACK generated for the valid downlink time unit is inserted into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the valid downlink time unit.

[0141] For invalid downlink time units, HARQ-NACK is generated according to predefined rules, and based on the starting point of the HARQ-ACK / NACK corresponding to the invalid downlink time unit in the HARQ-ACK / NACK codebook, the HARQ-NACK generated for the invalid downlink time unit is inserted into the HARQ-ACK / NACK codebook to fill the space.

[0142] Preferably, for downlink time units within invalid downlink time units that have not received a PDSCH, a HARQ-NACK is generated according to a predefined rule, and based on the position of the HARQ-ACK / NACK corresponding to the downlink time unit that has not received a PDSCH in the HARQ-ACK / NACK codebook, the generated HARQ-NACK is inserted into the HARQ-ACK / NACK codebook as a placeholder. However, for downlink time units within invalid downlink time units that have received a PDSCH but whose corresponding HARQ-ACK / NACK is not the uplink time unit, a HARQ-ACK / NACK is generated based on the PDSCH, and the generated HARQ-ACK / NACK is inserted into the HARQ-ACK / NACK codebook.

[0143] When the number of HARQ-ACK / NACK bits corresponding to a valid downlink time unit is greater than the minimum number of bits that can be occupied by HARQ-ACK / NACK for each downlink time unit, the HARQ-ACK / NACK for the valid downlink time unit will occupy the position of the HARQ-ACK / NACK for the immediately following downlink time unit. Conversely, when the position of HARQ-ACK / NACK for an invalid downlink time unit is occupied by HARQ-ACK / NACK for a valid downlink time unit, the number of HARQ-ACK / NACK bits corresponding to the invalid downlink time unit will be determined as the difference between the number of bits that can be occupied by HARQ-ACK / NACK for each downlink time unit and the number of bits occupied by HARQ-ACK / NACK for the valid downlink time unit. In other words, the number of HARQ-ACK / NACK bits Z' for which PDSCH was not received in the corresponding downlink time unit (called an invalid downlink time unit) is determined based on whether it was occupied by ACK / NACK for a valid downlink time unit. If it was not occupied by HARQ-ACK / NACK for a valid downlink time unit, then Z' = Y. If the bit is occupied by a valid downlink time unit HARQ-ACK / NACK, assuming the number of occupied bits is Y1, then Z' = Y - Y1. When Y1 = Y, Z' = 0.

[0144] Therefore, to avoid overlap of HARQ-ACK / NACK bits in the PDSCH of valid time units, the number of downlink time units L' scheduled by the base station to feed back HARQ-ACK / NACK in the same uplink time unit must be less than or equal to X / Z. For example, when X = 16, L = 8, and Z = 4, although the feedback time window size L = 8 determined according to the HARQ-ACK / NACK timing, within the feedback window, the number of downlink time units L' that the base station can schedule to feed back HARQ-ACK / NACK in the same uplink time unit is < 4 (X / Z).

[0145] Furthermore, to avoid the overlap of HARQ-ACK / NACK bits in the PDSCH of valid time units, the base station should avoid scheduling PDSCHs of adjacent time units that feed back HARQ-ACK / NACK in the same uplink time unit.

[0146] Figure 7 This is a schematic diagram of generating HARQ-ACK / NACK based on a downlink time unit according to a first exemplary embodiment of the present invention.

[0147] Reference Figure 7Assuming X = 16, L = 8, Y = 2, and Z = 4, the HARQ-ACK / NACK codebook length is 16. Assume the HARQ-ACK / NACK will be fed back in uplink time unit m, and the feedback window contains downlink time units m-11, m-10, ..., m-4, with a length of 8. The time unit index for downlink time unit m-11 is 0, and so on, with the time unit index for downlink time unit m-4 being 7. If the user equipment receives a PDSCH in time unit index 2, it generates a 4-bit HARQ-ACK / NACK based on the PDSCH decoding result. If no PDSCH is received in other time units, bits 0 to 3 in the HARQ-ACK / NACK codebook, corresponding to time unit indices 0 and 1 respectively, generate Y = 2 bits of HARQ-NACK due to lack of scheduling; bits 4 to 7, corresponding to time unit index 2, generate a 4-bit HARQ-ACK / NACK based on the PDSCH decoding result. It is easy to see that the 4 bits of time index unit 2 occupy the 2-bit position of time index unit 3. Bits 8 to 15 correspond to downlink time unit indices 4 to 7, respectively. Since downlink time units 4, 5, and 7 are not scheduled, although downlink time unit 6 is scheduled, its corresponding HARQ-ACK / NACK is fed back in uplink time unit m+1, so it is also an invalid time unit relative to uplink time unit m. Therefore, bits 8 to 15 are all HARQ-NACK. Similarly, for uplink time unit m+1, the feedback window includes downlink time units m-10, m-9, ..., m-3, with a length of 8. Within the feedback window, only downlink time unit m-5 (time unit index 5) schedules PDSCH and feeds back HARQ-ACK / NACK in uplink time unit m+1. The HARQ-ACK / NACK codebook size is 16, where bits 12 to 15 generate HARQ-ACK / NACK based on the received PDSCH, and bits 0 to 11 generate HARQ-NACK.

[0148] According to a first exemplary embodiment of the present invention, by configuring the HARQ-ACK / NACK codebook size at the base station, the feedback overhead of ACK / NACK can be effectively controlled, while avoiding the uncertainty of the HARQ-ACK / NACK codebook. The base station determines a better HARQ-ACK / NACK codebook size based on scheduling flexibility and feedback overhead. It is easy to see that in this scheme, even if the UE misses the scheduled PDSCH, it will not lead to the problem of uncertain HARQ-ACK / NACK feedback codebook size or uncertain HARQ-ACK / NACK bit order. This is because the ACK / NACK feedback codebook size is configured by a higher layer, and the starting point of the HARQ-ACK / NACK bits for each HARQ process or downlink time unit is also fixed.

[0149] The second exemplary embodiment of the present invention will now be described.

[0150] In a second exemplary embodiment of the present invention, in step 102, the user equipment determines the size of the HARQ-ACK / NACK codebook based on the size of the feedback window corresponding to the HARQ-ACK / NACK in the uplink time unit. Here, the set of all downlink time units that may simultaneously feed back HARQ-ACK / NACK in the uplink time unit, determined by all possible values ​​of the HARQ-ACK / NACK timing, is called a feedback window.

[0151] Specifically, the user equipment can determine the size of the feedback window based on the number of possible values ​​for the HARQ-ACK / NACK timing information. For example, the size of the feedback window corresponding to the uplink time unit is obtained by calculating 2 to the power of N using the number of bits N of the HARQ-ACK / NACK timing information indicated in the DCI; the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit is obtained by combining the size of the feedback window corresponding to the uplink time unit with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit. Here, the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is predefined by the standard or configured by a higher layer.

[0152] Preferably, the number of HARQ-ACK / NACK bits corresponding to each downlink time unit can be determined based on the maximum number of transport blocks (TB) that can be sent in each downlink time unit.

[0153] Preferably, the number of HARQ-ACK / NACK bits corresponding to each downlink time unit can be determined based on the maximum number of coded blocks (CBs) that can be sent in each downlink time unit.

[0154] Preferably, the number of HARQ-ACK / NACK bits corresponding to each downlink time unit can be determined based on the maximum number of coded block groups (CBs) that can be transmitted in each downlink time unit. If the base station configures the UE to dynamically switch between CB-based scheduling and transport block-based scheduling, the number of HARQ-ACK bits for the UE is always determined based on the maximum number of CBs that can be transmitted. For example, the base station configures the UE with CB-based scheduling and configures two DCIs: one for CB-based scheduling and one for transport block scheduling. The base station can dynamically use any DCI to schedule the UE, but the UE always determines the number of CBs that can be transmitted when feeding back HARQ-ACK. Assuming the maximum number of CBs that can be transmitted is 4, when the base station schedules the transmission of a TB (Transport Block Group), the UE still feeds back a 4-bit HARQ-ACK, where the first bit is generated based on the decoding result of the TB, and the other 3 bits are placeholder bits, such as NACK. If the working carrier can support the transmission of two transport blocks and is configured with coded block group-based scheduling, in one implementation, regardless of whether the base station's dynamic scheduling is based on coded block groups or transport blocks, the HARQ-ACK bit is always equal to (2 * the maximum number of coded block groups that can be transmitted). In another implementation, regardless of whether the base station's dynamic scheduling is based on coded block groups or transport blocks, the HARQ-ACK bit is always equal to (the maximum number of coded block groups that can be transmitted). This implementation can be independent of the spatial dimension binding of the existing RRC signaling configuration in the system. For example, without RRC configuration signaling, once coded block group-based scheduling is configured, the HARQ-ACK bit is always equal to (the maximum number of coded block groups that can be transmitted), or there is an additional RRC configuration signaling independent of the existing signaling.

[0155] Preferably, the control signaling may include information indicating that the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on the maximum number of transport blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded block groups that can be transmitted in each downlink time unit.

[0156] According to an exemplary embodiment, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit can be obtained by multiplying the size of the feedback window corresponding to the uplink time unit by the number of HARQ-ACK / NACK bits corresponding to each downlink time unit.

[0157] For example, if the downlink control command (DCI) uses N bits to indicate the timing of HARQ-ACK / NACK (i.e., the timing relationship between PDSCH and HARQ-ACK / NACK), then M = 2^N. This means that within the same uplink time unit, at most M downlink time units' worth of PDSCH ACK / NACK can be fed back. Therefore, the ACK / NACK codebook size is a function of M. For example, the codebook size could be M*Z, where Z is the number of HARQ-ACK / NACK bits corresponding to each downlink time unit.

[0158] According to another exemplary embodiment, if the number of HARQ-ACK / NACK bits in each downlink time unit is not equal, for example, some downlink time units are based on HARQ-ACK / NACK feedback based on transport blocks, and some downlink time units are based on HARQ-ACK / NACK feedback based on coded block groups, then the number of HARQ-ACK / NACK feedback bits in all downlink time units within the feedback window is added together to determine the HARQ-ACK / NACK codebook size.

[0159] Preferably, if some time units within the HARQ-ACK / NACK timing range indicated in the downlink control command (DCI) are time units that definitely do not transmit downlink PDSCH, then the HARQ-ACK / NACK codebook size needs to be determined after removing these time units. For example, in a TDD system, if the time unit is configured as an uplink time unit. For example, if 3 bits indicate HARQ-ACK / NACK timing, the difference mn between the PDSCH time unit n and the corresponding HARQ-ACK / NACK time unit m can be k0+0, k0+1, ..., k0+7. If time units m-k0 and m-k0-1 are uplink time units, then the HARQ-ACK / NACK codebook size is determined according to M = (8-2) = 6.

[0160] Preferably, the time unit in which PDSCH is not sent can be determined by semi-static signaling, such as RRC signaling, or by dynamic signaling, such as DCI indication.

[0161] Preferably, when calculating the HARQ-ACK / NACK codebook size, the size of the feedback window corresponding to the uplink time unit is obtained by removing the downlink time units that the signaling indicates must not send PDSCH.

[0162] Preferably, when calculating the HARQ-ACK / NACK codebook size, the size of the feedback window corresponding to the uplink time unit is obtained by removing downlink time units that are indicated by semi-static signaling as definitely not sending PDSCH, and by not removing downlink time units that are indicated by dynamic signaling as definitely not sending PDSCH. This approach avoids the problem of the ACK / NACK codebook size generated by the user equipment (UE) being inconsistent with the ACK / NACK codebook size expected by the base station due to missed or incorrect detection of dynamic signaling.

[0163] According to one aspect of the second embodiment of the present invention, in step 102, the user equipment may determine the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit based on the size of the HARQ-ACK / NACK codebook configured by the base station.

[0164] The control signaling may further include the total number of HARQ processes that can be supported in an uplink time unit and the HARQ process ID, or the control signaling may also include the HARQ process ID, and the total number of HARQ processes that can be supported in an uplink time unit is predefined by the standard. Therefore, the user equipment can generate a HARQ-ACK / NACK codebook corresponding to the uplink time unit based on the HARQ process.

[0165] Therefore, in step 102, the user equipment can determine the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook based on the size of the HARQ-ACK / NACK codebook, the total number of HARQ processes that can be supported in an uplink time unit, and the ID of each HARQ process.

[0166] Specifically, the minimum number of bits Y that can be occupied by each HARQ process is obtained by dividing the size X of the determined HARQ-ACK / NACK codebook by the total number L of HARQ processes that can be supported in one uplink time unit, i.e., Y = (X / L).

[0167] Then, by multiplying the minimum number of bits that HARQ-ACK / NACK can occupy for each HARQ process by the ID i of the HARQ process for each downlink time unit corresponding to the uplink time unit, for example, i = 0, 1, ..., L-1, the starting point Y*i, i = 0, 1, ..., L-1 of the HARQ-ACK / NACK corresponding to each downlink time unit corresponding to the uplink time unit in the HARQ-ACK / NACK codebook is obtained.

[0168] In step 103, the user equipment can generate HARQ-ACK / NACK based on the HARQ process. Here, the HARQ process can be divided into valid HARQ processes and invalid HARQ processes. A valid HARQ process refers to a HARQ process that receives a PDSCH in the downlink time unit corresponding to the uplink time unit, and the time difference between the uplink time unit and the downlink time unit where the PDSCH is located is greater than or equal to a predefined minimum delay. An invalid HARQ process refers to a HARQ process that does not receive a PDSCH in the downlink time unit corresponding to the uplink time unit, and / or receives a PDSCH in the downlink time unit, but the time difference between the uplink time unit and the downlink time unit where the PDSCH is located is less than a predefined minimum delay, and / or receives a PDSCH in the downlink time unit, but the HARQ-ACK / NACK of the PDSCH has been fed back before the uplink time unit.

[0169] Preferably, a valid HARQ process refers to a HARQ process that feeds back HARQ-ACK / NACK in the uplink time unit, meaning that the UE receives the PDSCH in the downlink time unit, and the HARQ-ACK / NACK of the PDSCH is fed back in the uplink time unit. If the UE receives the PDSCH in the downlink time unit, but the HARQ-ACK / NACK of the PDSCH is not fed back in the uplink time unit, then for the uplink time unit, this HARQ process is an invalid HARQ process.

[0170] For a valid HARQ process, the user equipment generates a HARQ-ACK / NACK based on the received PDSCH, and inserts the HARQ-ACK / NACK generated for the valid HARQ process into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the downlink time unit of the valid HARQ process.

[0171] For invalid HARQ processes, the user equipment generates HARQ-NACK according to predefined rules, and inserts the HARQ-NACK generated for the invalid HARQ process into the HARQ-ACK / NACK codebook based on the starting point of the HARQ-ACK / NACK corresponding to the downlink time unit corresponding to the invalid HARQ process.

[0172] When the number of HARQ-ACK / NACK bits corresponding to a valid HARQ process exceeds the minimum number of bits that can be occupied by HARQ-ACK / NACK for each HARQ process, the user equipment will occupy the position of the HARQ-ACK / NACK corresponding to the valid HARQ process and the position of the HARQ-ACK / NACK corresponding to the immediately following HARQ process. For example, specifically, the number Z of ACK / NACK bits for a HARQ process (i.e., a valid HARQ process) receiving PDSCH in the corresponding time unit can be greater than or equal to Y. In this case, the ACK / NACK bits corresponding to the HARQ process may occupy the number of ACK / NACK bits for the immediately following HARQ process.

[0173] When the HARQ-ACK / NACK bit corresponding to an invalid HARQ process is occupied by the HARQ-ACK / NACK bit corresponding to a valid HARQ process, the user equipment determines the number of HARQ-ACK / NACK bits corresponding to the invalid HARQ process as the difference between the number of bits available for HARQ-ACK / NACK for each HARQ process and the number of bits occupied for HARQ-ACK / NACK for the valid HARQ process. For example, the number of ACK / NACK bits Z' for a HARQ process that did not receive PDSCH in the corresponding time unit (i.e., invalid HARQ processing) is determined based on whether it is occupied by the ACK / NACK bit of a valid HARQ process. If it is not occupied by the ACK / NACK bit of a valid HARQ process, then Z' = Y. If it is occupied by the ACK / NACK bit of a valid HARQ process, assuming the number of bits occupied is Y1, then Z' = Y - Y1. When Y = Y1, Z' = 0.

[0174] Therefore, according to embodiments of the present invention, in order to avoid the overlap of ACK / NACK bits of valid HARQ processes, the base station should avoid scheduling adjacent HARQ processes that feed back ACK / NACK in the same uplink time unit when performing scheduling.

[0175] According to another aspect of the second exemplary embodiment, the user equipment determines the downlink time unit index of each downlink time unit corresponding to the uplink time unit based on information about HARQ-ACK / NACK timing, wherein the downlink time unit index of each downlink time unit corresponding to the uplink time unit represents the relative time order of each downlink time unit corresponding to the uplink time unit in the feedback window; and determines the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook according to either a descending order based on the relative time order (the HARQ-ACK / NACK order of the downlink time units is in reverse order to the feedback timing indicated in the DCI transmitted by the downlink time unit) or a ascending order based on the relative time order (the HARQ-ACK / NACK order of the downlink time units is in the same order to the feedback timing indicated in the DCI transmitted by the downlink time unit).

[0176] For example, 2 bits in the DCI indicate the timing of HARQ-ACK / NACK (i.e., the time relationship between PDSCH and HARQ-ACK / NACK). Assuming the uplink time unit where the PUCCH that feeds back HARQ-ACK / NACK is located is m, then downlink time units m-(k0+3) to m-(k0) may all feed back ACK / NACK in uplink time unit m. For example, the 2 bits in the DCI could be 11, 10, 01, and 00 respectively. During base station scheduling, one or more of the four downlink time units can be scheduled, and when scheduling the downlink time units, the 2 bits in the DCI can take any value. However, as long as at least one of the downlink time units' HARQ-ACK / NACK falls in uplink time unit m, the UE determines the HARQ-ACK / NACK codebook size according to the four downlink time units, and determines the position of the HARQ-ACK / NACK bit of the PDSCH in the HARQ-ACK / NACK codebook according to the relative time order of the downlink time unit where the actual received PDSCH is located in these four downlink time units.

[0177] For example, the HARQ-ACK / NACK codebook size of the PUCCH in uplink time unit m is M*Z=4*2=8, that is, the HARQ-ACK / NACK codebook size is 8. If we follow the order of HARQ-ACK / NACK feedback times from largest to smallest as indicated by DCI, the first and second bits are the HARQ-ACK / NACK of the PDSCH in time unit m-(k0+3), the third and fourth bits are the HARQ-ACK / NACK of the PDSCH in time unit m-(k0+2), and so on.

[0178] After determining the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook using this method, the user equipment generates the HARQ-ACK / NACK codebook based on valid downlink time units and invalid downlink time units respectively. A valid downlink time unit refers to a downlink time unit where a PDSCH is received and the corresponding HARQ-ACK / NACK is an uplink time unit. An invalid downlink time unit refers to a downlink time unit where a PDSCH is not received, or a downlink time unit where a PDSCH is received but the corresponding HARQ-ACK / NACK is not an uplink time unit.

[0179] For a valid downlink time unit, HARQ-ACK / NACK is generated based on the received PDSCH, and the HARQ-ACK / NACK generated for the valid downlink time unit is inserted into the HARQ-ACK / NACK codebook based on the position of the HARQ-ACK / NACK corresponding to the valid downlink time unit.

[0180] For downlink time units where PDSCH is not received, the user equipment generates a HARQ-NACK placeholder according to predefined rules.

[0181] For a received PDSCH but whose corresponding HARQ-ACK / NACK uplink time unit is not the downlink time unit, the user equipment generates a HARQ-NACK placeholder according to predefined rules.

[0182] Preferably, for downlink time units where no PDSCH is received, the user equipment generates a HARQ-NACK placeholder according to predefined rules. However, for downlink time units where a PDSCH is received but the corresponding HARQ-ACK / NACK is not the uplink time unit, the user equipment still generates a HARQ-ACK / NACK based on the PDSCH decoding result and inserts the generated HARQ-ACK / NACK into the HARQ-ACK / NACK codebook.

[0183] For example, Figure 8 This is a schematic diagram of uplink and downlink mapping based on downlink time units according to a second exemplary embodiment of the present invention.

[0184] Reference Figure 8For example, the time difference between the 2-bit indication PDSCH and the feedback HARQ-ACK / NACK in the DCI can be 3, 4, 5, or 6. Assuming the number of HARQ-ACK / NACK bits fed back in each downlink time unit is Z = 2, then the HARQ-ACK / NACK codebook size is M*Z = 8. The 2-bit indication in the DCI for scheduling downlink time unit m is 10, meaning HARQ-ACK / NACK is fed back in uplink time unit m+5. The 2-bit indication in the DCI for scheduling downlink time unit m+1 is 01, meaning HARQ-ACK / NACK is fed back in uplink time unit m+5. The 2-bit indication in the DCI for scheduling downlink time unit m+2 is 01, meaning HARQ-ACK / NACK is fed back in uplink time unit m+6. Therefore, for uplink time unit m+5, the first two bits of the ACK / NACK codebook correspond to downlink time unit m-1. Since there is no scheduled data, a 2-bit HARQ-NACK is generated. For the middle four bits of the HARQ-ACK / NACK codebook, the HARQ-ACK / NACK result is determined based on the demodulation results of the PDSCH received in downlink time units m and m+1, respectively. For the last two bits of the HARQ-ACK / NACK codebook, since the HARQ-ACK / NACK of the PDSCH in downlink time unit m+2 is fed back in uplink time unit m+6, a 2-bit HARQ-NACK is generated. For uplink time unit m+6, the first four bits of the HARQ-ACK / NACK codebook are NACK, because the downlink time unit corresponding to the feedback HARQ-ACK / NACK in downlink time units m and m+1 is m+5.

[0185] According to another aspect of the second embodiment of the present invention, the control signaling may further include information indicating the relative time order of the currently scheduled downlink time units in the feedback window corresponding to the uplink time unit. Therefore, the user equipment can determine the position of the HARQ-ACK / NACK corresponding to all scheduled downlink time units corresponding to the uplink time unit in the HARQ-ACK / NACK codebook based on the information regarding the relative time order of all scheduled downlink time units corresponding to the uplink time unit in the feedback window corresponding to the uplink time unit, wherein the currently scheduled downlink time unit refers to the time unit in which the user equipment receives the PDSCH from the base station.

[0186] Preferably, when the base station configures carrier aggregation for the user terminal, if the feedback window size on each carrier is different, the size of the HARQ-ACK / NACK codebook is determined based on the maximum length of each feedback window multiplied by the number of configured serving cells. For example, if the base station configures two serving cells for the user terminal, with one serving cell having a feedback window size of 4 and the other serving cell having a feedback window size of 2, then the size of the HARQ-ACK codebook is determined as follows: the feedback window size for each carrier is 4 * the number of serving cells is 2 * the number of HARQ-ACK bits per downlink time unit. For a serving cell with an actual feedback window size of 2, a HARQ-ACK feedback of length 4 is achieved by generating placeholder bits.

[0187] Preferably, the control signaling may further include a first type of DAI, wherein the first type of DAI indicates one of the following: the relative time order of the currently scheduled downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the bit position of the HARQ-ACK / NACK bit of the currently scheduled downlink time unit in the HARQ-ACK / NACK codebook. Therefore, the user equipment can determine the position of the HARQ-ACK / NACK bit corresponding to each downlink time unit of all scheduled downlink time units corresponding to the uplink time unit in the HARQ-ACK / NACK codebook based on the value of the first type of DAI of all scheduled downlink time units corresponding to the uplink time unit.

[0188] For example, Figure 9 This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a second exemplary embodiment of the present invention.

[0189] Reference Figure 9The DCI uses 2 bits to indicate the HARQ-ACK / NACK feedback time, representing time differences of 1, 2, 3, and 4 between HARQ-ACK / NACK and PDSCH, respectively. Assuming the DCI indicating a HARQ-ACK / NACK feedback time difference of 2 for the PDSCH of downlink time unit n, then n+3 will provide HARQ-ACK / NACK. Similarly, if the DCI indicating a HARQ-ACK / NACK feedback time difference of 1 for the PDSCH of downlink time unit n+1, then n+2 will provide HARQ-ACK / NACK. Finally, if the DCI indicating a HARQ-ACK / NACK feedback time difference of 1 for the PDSCH of downlink time unit n+2, then n+3 will provide HARQ-ACK / NACK. If two downlink time units' HARQ-ACK / NACK are fed back in uplink time unit n+3, then the first type DAI indicated in the DCI of downlink time unit n and time unit n+2 is DAI=1 and DAI=2 respectively, while the first type DAI indicated in the DCI of downlink time unit n+1 is 1.

[0190] Preferably, in the control signaling, the first type of DAI can be co-encoded with information about HARQ-ACK / NACK timing.

[0191] When the HARQ-ACK / NACK feedback time indication value is at its maximum, for example, 2 bits indicating a HARQ-ACK / NACK time difference of 1 to 4, then, assuming the DCI indicating a HARQ-ACK / NACK time difference of 4 for downlink time unit n, the first type of DAI must be 1. That is, the current downlink time unit must be the first downlink time unit to provide HARQ-ACK / NACK feedback in uplink time unit n+4, because downlink time units before downlink time unit n cannot be mapped to uplink time unit n+4. However, when the indicated HARQ-ACK / NACK time difference is 3, the first type of DAI must be either 1 or 2, meaning there are only two possibilities: either the current downlink time unit n is the first downlink time unit to provide HARQ-ACK / NACK feedback in uplink time unit n+3, or downlink time unit n-1 is the first downlink time unit to provide HARQ-ACK / NACK feedback in uplink time unit n+3, and downlink time unit n is the second downlink time unit to provide HARQ-ACK / NACK feedback in uplink time unit n+3. Similarly, when the indicated HARQ-ACK / NACK time difference is 1, the first type of DAI can be 1, 2, 3, or 4. Therefore, the total number of combinations of HARQ-ACK / NACK timing and the first type of DAI is 10, not 16. If 4-bit joint encoding is used, the remaining 6 states can be used for other purposes.

[0192] To further compress the bits, part of the combination of Type I DAI and HARQ-ACK / NACK timing can be removed. For example, 3 bits can be used to jointly indicate the Type I DAI and HARQ-ACK / NACK feedback times. Assuming the HARQ-ACK / NACK feedback delay ranges from 3 to 6, Table 1 shows the interrelationships of the joint coding for downlink time unit n.

[0193] Table 1

[0194]

[0195]

[0196] After determining the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook in this way, the user equipment can, starting from the beginning of the HARQ-ACK / NACK codebook, sequentially insert the HARQ-ACK / NACK corresponding to all scheduled downlink time units according to the relative time order indicated by the first type DAI of all scheduled downlink time units corresponding to the uplink time unit, and insert placeholder bits in subsequent positions.

[0197] Furthermore, when a discontinuous Type I DAI is detected, the user equipment can determine that a PDSCH corresponding to the missing Type I DAI downlink time unit has been missed. For the missed PDSCH, a HARQ-NACK is generated, and the generated HARQ-NACK is inserted into the HARQ-ACK / NACK codebook at the position corresponding to the relative time sequence indicated by the missing Type I DAI.

[0198] The third exemplary embodiment of the present invention is described below. .

[0199] According to one aspect of a third exemplary embodiment of the present invention, the size of the HARQ-ACK / NACK codebook generated by the user equipment is not fixed, but corresponds to the number of downlink time units for which HARQ-ACK / NACK PDSCHs need to be fed back in the uplink time unit.

[0200] Preferably, the control signaling may include a first type of DAI, which is carried via DCI. The first type of DAI indicates one of the following: the relative time order of the currently scheduled downlink time unit among all scheduled downlink time units corresponding to the uplink time unit; and the bit position of the HARQ-ACK / NACK bit of the currently scheduled downlink time unit in the HARQ-ACK / NACK codebook. Assuming the number of HARQ-ACK / NACK bits in each downlink time unit is N0, the starting point of the HARQ-ACK / NACK bit in the HARQ-ACK / NACK codebook for the downlink time unit is determined to be the X0*N0-1th bit based on the first type of DAI value X0. For example, if N0 = 2, then when the first type of DAI = 1, the HARQ-ACK / NACK bit corresponds to the 1st and 2nd bits in the HARQ-ACK / NACK codebook, and so on. When the first type of DAI = 4, the HARQ-ACK / NACK bit corresponds to the 7th and 8th bits in the HARQ-ACK / NACK codebook. Therefore, the user equipment can also determine the size of the HARQ-ACK / NACK codebook based on the first type of DAI. Specifically, the user equipment determines the size of the HARQ-ACK / NACK codebook by combining the maximum value of the first type of DAI among all scheduled downlink time units corresponding to the uplink time unit with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit. After determining the size of the HARQ-ACK / NACK codebook in this way, the user equipment can also determine the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook based on the value of the first type of DAI of each downlink time unit among all scheduled downlink time units corresponding to the uplink time unit.

[0201] Preferably, the first type of DAI can also represent the starting position of the HARQ-ACK / NACK bit corresponding to the currently scheduled PDSCH in the HARQ-ACK / NACK codebook. For example, the value of the first type of DAI X0 = 5 for the second scheduled downlink time unit indicates that the starting position of the HARQ-ACK / NACK bit in this downlink time unit is 5 in the HARQ-ACK / NACK codebook. That is, X0 has already factored in N0. The advantage of this method is that it can support cases where the number of HARQ-ACK / NACK bits in each downlink time unit is not equal, that is, N0 can be different for each downlink time unit. For example, the first downlink time unit is based on HARQ-ACK / NACK feedback from the coded block group, and N0 = 4, while the second downlink time unit is based on HARQ-ACK / NACK feedback from the transport block group, and N0 = 1. As mentioned above, the value of the first type of DAI for the second downlink time unit is X0 = 5. That is to say, the count of the first type of DAI is counted in units of coded block groups, rather than based on the PDCCH as in the prior art. Similarly, when the UE is configured for carrier aggregation, this method can support different N0 values ​​for each downlink time unit / downlink carrier. Because the maximum range of the first type DAI is expanded in this method, more bits are required. For example, compared to the existing 2-bit first type DAI in LTE, this method requires 3 or 4 bits for the first type DAI.

[0202] If at least one working carrier can support the transmission of two transport blocks, the first type of DAI based on the coding block group count can work in at least three ways: (1) When the first type of DAI counts a downlink time unit, it does not distinguish whether the downlink time unit is one or two transport blocks, but counts according to the total number of coding blocks of all transport blocks in the downlink time unit. Then the number of HARQ-ACK bits fed back is consistent with the first type of DAI. (2) If the base station is configured with spatial dimension binding, when the first type of DAI counts a downlink time unit, it counts according to the total number of coding blocks of one transport block. When two transport blocks are scheduled, the HARQ-ACK of each of the two transport blocks is ANDed. In the example above, assume that the first downlink time unit is based on the HARQ-ACK / NACK fed back from the coding block group and two transport blocks are scheduled, and the second downlink time unit is based on the HARQ-ACK / NACK fed back from the transport block group and one transport block is scheduled, N0=1. For the first downlink time unit, before binding, the number of HARQ-ACK bits per transport block is N0 = 4, and after binding, N0 = 4 bits are still fed back. The value of the first type DAI for the second downlink time unit, X0 = 5, still indicates that the starting position of the HARQ-ACK / NACK bits in the HARQ-ACK / NACK codebook for this downlink time unit is 5. (3) If the base station does not configure spatial dimension binding, when the first type DAI counts a downlink time unit, it counts according to the total number of coded blocks of a transport block, but the number of HARQ-ACK bits fed back is twice the count. In the example above, assume that the first downlink time unit is based on the HARQ-ACK / NACK fed back from the coded block group and two transport blocks are scheduled, and the second downlink time unit is based on the HARQ-ACK / NACK fed back from the transport block group and one transport block is scheduled, N0 = 1. For the first downlink time unit, the number of HARQ-ACK bits per transport block is N0 = 4, and a total of 2*N0 bits are fed back. For the second downlink time unit, the scheduled transport block has 1 HARQ-ACK bit (N0), and sends 1 placeholder bit, for a total of 2 bits fed back. The first type DAI value X0 = 5 for the second downlink time unit indicates that the starting position of the HARQ-ACK / NACK bits in the HARQ-ACK / NACK codebook for this downlink time unit is 2*X0-1. The total number of bits in the HARQ-ACK / NACK codebook is 10.

[0203] Preferably, the first type of DAI determined in the above manner can be used only when dynamically determining the HARQ-ACK / NACK codebook of PDSCH for multiple carriers or time units, and not when semi-statically determining the HARQ-ACK / NACK codebook of PDSCH for multiple carriers or time units. For example, the first type of DAI based on PDSCH counting in the prior art can be used, or no DAI can be used at all.

[0204] Preferably, in the control signaling, the first type of DAI can be co-encoded with information about HARQ-ACK / NACK timing.

[0205] Preferably, the control signaling further includes a second type of DAI, which is carried via DCI. According to an exemplary embodiment, the second type of DAI indicates the total number of all scheduled downlink time units corresponding to the uplink time unit. In this case, the user equipment can determine the size of the HARQ-ACK / NACK codebook by combining the value of the second type of DAI with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit. Assuming the number of HARQ-ACK / NACK bits for each downlink time unit is N0, and the value of the second type of DAI is Y0, then the size of the HARQ-ACK / NACK codebook is Y0*N0. Thus, the size of the HARQ-ACK / NACK codebook is not fixed, but corresponds to the total number of downlink time units corresponding to the uplink time unit.

[0206] For example, Figure 10 This is a schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention.

[0207] Reference Figure 10In the DCI, there are 2 bits indicating the HARQ-ACK / NACK feedback time, indicating the time difference between HARQ-ACK / NACK and PDSCH as 1, 2, 3, and 4, respectively. Assuming the DCI indicating a HARQ-ACK / NACK feedback time difference of 3 for the PDSCH of downlink time unit n, then n+3 will provide HARQ-ACK / NACK. Similarly, if the DCI indicating a HARQ-ACK / NACK feedback time difference of 1 for the PDSCH of downlink time unit n+1, then n+2 will provide HARQ-ACK / NACK. And if the DCI indicating a HARQ-ACK / NACK feedback time difference of 1 for the PDSCH of downlink time unit n+2, then n+3 will provide HARQ-ACK / NACK. If two downlink time units of HARQ-ACK / NACK are fed back at uplink time unit n+3, then the second type DAI indicated in the DCI of downlink time unit n and time unit n+2 is 2 (assuming 00 represents DAI=1, i.e., 1 downlink time unit, and 01 represents DAI=2, i.e. 2 time units), while the second type DAI indicated in the DCI of downlink time unit n+1 is 1.

[0208] According to another exemplary embodiment, the second type of DAI indicates the total number of downlink time units from the first downlink time unit to the current downlink time unit among all scheduled downlink time units corresponding to the uplink time unit. In this case, the user equipment can determine the size of the HARQ-ACK / NACK codebook by combining the maximum value of the second type of DAI among all scheduled downlink time units corresponding to the uplink time unit with the number of HARQ-ACK / NACK bits corresponding to each downlink time unit. Thus, the size of the HARQ-ACK / NACK codebook is not fixed, but corresponds to the total number of downlink time units among all scheduled downlink time units corresponding to the uplink time unit. In this case, when the user equipment is configured with only one serving cell, i.e., not operating in carrier aggregation, the first type of DAI and the second type of DAI are the same. Then, only one DAI needs to be indicated in the DCI.

[0209] For example, Figure 11 This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention.

[0210] Reference Figure 11In the DCI, there are 2 bits indicating the HARQ-ACK / NACK feedback time, indicating the time difference between HARQ-ACK / NACK and PDSCH as 1, 2, 3, and 4, respectively. Assuming the DCI indicating a HARQ-ACK / NACK feedback time difference of 3 for the PDSCH of downlink time unit n, then n+3 will provide HARQ-ACK / NACK. Similarly, if the DCI indicating a HARQ-ACK / NACK feedback time difference of 1 for the PDSCH of downlink time unit n+1, then n+2 will provide HARQ-ACK / NACK. And if the DCI indicating a HARQ-ACK / NACK feedback time difference of 1 for the PDSCH of downlink time unit n+2, then n+3 will provide HARQ-ACK / NACK. If two downlink time units of HARQ-ACK / NACK are fed back in uplink time unit n+3, then the second type DAI indicated in the DCI of downlink time unit n is 1 (assuming 00 represents DAI=1, i.e., 1 downlink time unit, and 01 represents DAI=2, i.e. 2 time units), the second type DAI indicated in the DCI of downlink time unit n+1 is 1, and the second type DAI indicated in the DCI of downlink time unit n+2 is 2.

[0211] According to another exemplary embodiment, the second type of DAI can indicate the total number of bits in the HARQ-ACK / NACK codebook. That is, the value Y0 of the second type of DAI has factored in N0, and it can support cases where N0 is unequal for different downlink time units / downlink carriers, i.e., counted in units of CBG. In this case, the user equipment can determine the size of the HARQ-ACK / NACK codebook based on the number of bits indicated by the second type of DAI.

[0212] Preferably, in the control signaling, the first type DAI, the second type DAI, and information about HARQ-ACK / NACK timing can be jointly encoded.

[0213] For example, 5 bits can be used to jointly indicate the Type 1 and Type 2 DAI and the HARQ-ACK / NACK feedback time. This saves 1 bit compared to using 2 bits each to indicate the Type 1 DAI, 2 bits to indicate the Type 2 DAI, and 2 bits to indicate the HARQ-ACK / NACK feedback time. Therefore, Table 2 shows the relationship of the joint coding information for downlink time unit n.

[0214] Table 2

[0215]

[0216]

[0217] For example, Figure 12This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention.

[0218] Reference Figure 12 Assuming the HARQ-ACK / NACK timing range that can be indicated in the DCI is 3 to 6, and the maximum total number of downlink time units corresponding to the HARQ-ACK / NACK feedback within the same uplink time unit is 4, then, according to the 5-bit joint coding in Table 2, for downlink time unit n, the 5-bit indication is 00010, meaning the HARQ-ACK / NACK feedback is in uplink time unit n+6. Downlink time unit n is the first downlink time unit that provides HARQ-ACK / NACK feedback in uplink time unit n+6, i.e., the first type of DAI = 1, and the total number of downlink time units corresponding to the HARQ-ACK / NACK feedback in uplink time unit n+6 is 3, i.e., the second type of DAI = 3. For downlink time unit n+2, the 5-bit indicator is 01101, meaning the HARQ-ACK / NACK feedback is for uplink time unit n+6. Downlink time unit n+2 is the second downlink time unit after the HARQ-ACK / NACK feedback in uplink time unit n+6, i.e., Type I DAI = 2. The total number of downlink time units corresponding to the HARQ-ACK / NACK feedback in uplink time unit n+6 is 3, i.e., Type II DAI = 3. For downlink time unit n+3, the 5-bit indicator is 10010, meaning the HARQ-ACK / NACK feedback is for uplink time unit n+6. Downlink time unit n+3 is the third downlink time unit after the HARQ-ACK / NACK feedback in uplink time unit n+6, i.e., Type I DAI = 3. The total number of downlink time units corresponding to the HARQ-ACK / NACK feedback in uplink time unit n+6 is 3, i.e., Type II DAI = 3.

[0219] For example, Figure 13 This is another schematic diagram of uplink and downlink mapping based on downlink time units according to a third exemplary embodiment of the present invention.

[0220] Reference Figure 13Assuming the HARQ-ACK / NACK timing range that can be indicated in the DCI is 3 to 6, and the maximum total number of downlink time units corresponding to the HARQ-ACK / NACK feedback within the same uplink time unit is 4, then, according to the 5-bit joint coding in Table 2, for downlink time unit n, the 5-bit indication is 00001, meaning the HARQ-ACK / NACK feedback is in uplink time unit n+6. Downlink time unit n is the first downlink time unit that provides HARQ-ACK / NACK feedback in uplink time unit n+6, i.e., the first type of DAI = 1. Furthermore, the total number of downlink time units corresponding to the HARQ-ACK / NACK feedback in uplink time unit n+6 is 2, i.e., the second type of DAI = 2. For downlink time unit n+2, the 5-bit indicator is 00000, meaning the HARQ-ACK / NACK feedback is for uplink time unit n+8. Downlink time unit n+2 is the first downlink time unit to receive HARQ-ACK / NACK feedback after uplink time unit n+8, i.e., Type I DAI = 1. Furthermore, the total number of downlink time units corresponding to HARQ-ACK / NACK feedback after uplink time unit n+8 is 1, i.e., Type II DAI = 1. For downlink time unit n+3, the 5-bit indicator is 10001, meaning the HARQ-ACK / NACK feedback is for uplink time unit n+6. Downlink time unit n+2 is the second downlink time unit to receive HARQ-ACK / NACK feedback after uplink time unit n+6, i.e., Type I DAI = 2. Furthermore, the total number of downlink time units corresponding to HARQ-ACK / NACK feedback after uplink time unit n+6 is 2, i.e., Type II DAI = 2.

[0221] It is worth noting that the number of bits in the first type of DAI and / or the second type of DAI is limited, for example, 2 bits, but it can represent values ​​greater than 4 by modulo operation. For example, when the number M of downlink time units corresponding to the HARQ-ACK / NACK feedback of the same uplink time unit is greater than the range indicated by the DAI bits, the corresponding DAI value in the table in this embodiment is M modulo M_dai. For example, M = 8, but DAI is only 2 bits, then DAI = 3 in the table can represent 3 and 7.

[0222] Preferably, the control signaling may include a third type of DAI, wherein the content indicated by the third type of DAI is the same as the content indicated by the second type of DAI, or the third type of DAI indicates the total number of bits of the HARQ-ACK / NACK codebook that the base station expects to receive, and the total number of HARQ-ACK / NACK bits corresponding to the PDSCH actually scheduled by the base station is less than or equal to the expected total number of bits. For example, the control signaling DCI for scheduling uplink transmission includes the third type of DAI, and the control signaling DCI for scheduling downlink transmission includes the first and second types of DAI. When HARQ-ACK is transmitted on the PUSCH, if the PUSCH needs to perform rate matching based on the HARQ-ACK codebook, the size of the HARQ-ACK codebook is indicated by the third type of DAI. To ensure the UE has sufficient time for rate matching, it can be stipulated that for PDSCHs transmitting HARQ-ACK on the same PUSCH, the DCI that schedules the PDSCH and contains Type I and Type II DAIs cannot be later than the DCI that schedules the PUSCH and contains Type III DAIs. Alternatively, it can be stipulated that the time difference between the DCI containing Type I and Type II DAIs and the PUSCH cannot be less than a predefined value. Or, it can be stipulated that the time difference between the DCI containing Type I and Type II DAIs and the DCI containing Type III DAIs cannot be less than a predefined value. Alternatively, the time difference between the DCI containing Type I and Type II DAIs and the DCI containing Type III DAIs can be left unrestricted, but the base station must ensure that the size of the HARQ-ACK codebook indicated by Type II DAIs does not exceed the size of the HARQ-ACK codebook indicated by Type III DAIs.

[0223] Furthermore, the above descriptions all assume that the number of HARQ-ACK / NACK timing methods (M types) is equal to the maximum number of downlink time units corresponding to the HARQ-ACK / NACK responses within the same uplink time unit (M1). However, the joint coding scheme described above also applies to the case where the number of HARQ-ACK / NACK timing methods (M types) is greater than the maximum number of downlink time units corresponding to the HARQ-ACK / NACK responses within the same uplink time unit (M1).

[0224] According to another aspect of the invention, when generating the HARQ-ACK / NACK codebook, if the total number of uplink control signaling bits containing at least HARQ-ACK / NACK that needs to be fed back in the uplink time unit exceeds the maximum number of uplink control signaling bits that can be carried by the PUCCH resources configured by the base station, the user equipment can compress the HARQ-ACK / NACK bits that need to be fed back in the uplink time unit according to a predefined rule. Here, the maximum number of HARQ-ACK / NACK bits that can be carried by the PUCCH resources configured by the base station is predefined by the standard, or determined by the physical resources occupied by the PUCCH and the predefined coding rate, or determined by the PUCCH format. One implementation is to compress the HARQ-ACK / NACK feedback of the coded block / coded block group into the HARQ-ACK / NACK of the transport block. Assuming each transport block can be divided into a maximum of Ncb coded block groups, when the total number of HARQ-ACK / NACK responses exceeds the maximum number of HARQ-ACK / NACK bits that the base station's configured PUCCH resources can carry, if all Ncb' coded block groups are correctly decoded (where Ncb' is less than or equal to Ncb), the entire transport block is considered to have been transmitted correctly, and a 1-bit ACK is generated. If at least one of the Ncb' coded block groups is not correctly decoded, the entire transport block is considered to have been transmitted incorrectly, and a 1-bit HARQ-NACK is generated.

[0225] According to another aspect of the invention, when generating the HARQ-ACK / NACK codebook, if the total number of uplink control signaling bits requiring feedback (at least HARQ-ACK / NACK) in the uplink time unit exceeds the maximum number of uplink control signaling bits that the PUCCH resources configured by the base station can carry, the next larger PUCCH resource capable of carrying the total number of uplink control signaling bits requiring feedback is used to transmit the uplink control signaling in the uplink time unit. For example, the base station semi-statically configures four PUCCH resources for the user equipment, each capable of carrying a maximum number of ACK / NACK bits of Na1, Na2, and Na2, respectively. The base station instructs the user equipment to use the second PUCCH resource, but the user equipment finds that the total number of ACK / NACK bits requiring feedback exceeds Na1 but does not exceed Na2, then the user equipment uses the third PUCCH resource.

[0226] According to another aspect of the invention, when generating the HARQ-ACK / NACK codebook, if the total number of uplink control signaling bits containing at least HARQ-ACK / NACK that needs to be fed back in the uplink time unit exceeds the maximum number of uplink control signaling bits that the PUCCH resources configured by the base station can carry, the user equipment receives downlink scheduling information from the base station in the current downlink time unit or at least the last downlink time unit corresponding to the uplink time unit. This information indicates new PUCCH resources capable of carrying the total number of uplink control signaling bits that need to be fed back, and the user equipment uses the new PUCCH resources to transmit the uplink control signaling in the uplink time unit. For example, the base station semi-statically configures four types of PUCCH resources for the user equipment, each capable of carrying a maximum number of N bits for HARQ-ACK / NACK. a1 N a1 N a2 N a2 In the first and second downlink time units, the base station instructs the user equipment to use the second type of PUCCH resource, but in the third downlink time unit, the base station instructs the user equipment to use the third type of PUCCH resource, and the user equipment then uses the third type of PUCCH resource.

[0227] According to another aspect of the invention, when generating the HARQ-ACK / NACK codebook, if the total number of bits of HARQ-uplink control signaling to be fed back in the uplink time unit exceeds the maximum number of bits of uplink control signaling that the PUCCH resources configured by the base station can carry, the user equipment abandons sending HARQ-ACK / NACK for lower priority downlink time units, so that the total number of bits of uplink control signaling sent does not exceed the maximum number of bits of uplink control signaling that the PUCCH resources configured by the base station can carry. For example, when there are different service types, the priority of the PDSCH of eMBB is lower than the priority of the PDSCH of URLLC. Or, the priority of the PDSCH scheduled in the first type of DCI format is lower than the priority of the PDSCH scheduled in the second type of DCI format. Preferably, the control signaling may also include other uplink control signaling, such as channel state information.

[0228] It is worth noting that in the above embodiments, when the HARQ-ACK / NACK feedback in an uplink time unit comes only from a downlink time unit, one implementation is to determine the HARQ-ACK / NACK codebook and HARQ-ACK / NACK bit mapping in the manner described in the above embodiments. Another implementation is to generate the codebook based solely on the HARQ-ACK / NACK of a downlink time unit. When generating the codebook based on the HARQ-ACK / NACK of a downlink time unit, the HARQ-ACK / NACK codebook can be determined according to the actual number of scheduled coding blocks / groups. For example, the PDSCH transmitted in a downlink time unit can have a maximum of N coding block groups, and the maximum HARQ-ACK / NACK feedback is N bits. When only the HARQ-ACK / NACK of a downlink time unit is fed back in an uplink time unit, the user terminal feeds back k bits of HARQ-ACK / NACK, where k is the actual number of scheduled coding block groups, and k ≤ N. However, when multiple line time units of HARQ-ACK / NACK are fed back in one uplink time unit, the user terminal determines the number of HARQ-ACK / NACK feedback bits for each downlink time unit based on N.

[0229] According to another aspect of the invention, when generating the HARQ-ACK / NACK codebook, the base station can be configured to use the same number of HARQ-ACK / NACK bits for each downlink time unit and / or downlink carrier that requires HARQ-ACK / NACK feedback. For example, the different downlink time units and / or downlink carriers that provide HARQ-ACK / NACK feedback within the same uplink time unit may have different HARQ-ACK / NACK feedback methods. Some downlink time units / downlink carriers may use HARQ-ACK / NACK feedback based on coded block groups, with N1 HARQ-ACK / NACK bits per downlink time unit / downlink carrier, while other downlink time units / downlink carriers may use HARQ-ACK / NACK feedback based on transport blocks, with N2 HARQ-ACK / NACK bits per downlink time unit / downlink carrier. The base station can configure the UE to provide feedback on all downlink time units / downlink carriers with the same length, for example, by using N1 or N2 HARQ-ACK / NACK bits per downlink time unit / downlink carrier. For example, if configured to provide feedback according to N2, the HARQ-ACK / NACK of a transport block can be obtained by performing an AND operation on the HARQ-ACK / NACK of multiple coded block groups of a transport block, thus compressing from N1 bits to N2 bits. Alternatively, if configured to provide feedback according to N1, the N2 bits can be mapped to the first N2 bits of N1, and then placeholder bits are used for N1-N2 bits, thus expanding from N2 bits to N1 bits. In this example, if the second type DAI indicates the total number of downlink time units and / or downlink carriers requiring HARQ-ACK / NACK feedback, then the total number of bits in the HARQ-ACK / NACK codebook is second type DAI * N1 or second type DAI * N2. When at least one carrier is configured to support multiple transport blocks, according to existing technology, the base station configures each carrier to be spatially bound; that is, when a downlink carrier has two transport blocks requiring HARQ-ACK feedback, the HARQ-ACK of these two transport blocks is ANDed. Here, a bitwise AND operation is performed on N1 or N2 bits of HARQ-ACK in the two transport blocks, so that the number of HARQ-ACK bits for each downlink carrier is N1 or N2, thereby achieving a total number of bits in the HARQ-ACK / NACK codebook of type 2 DAI*N1 or type 2 DAI*N2.Alternatively, the base station may configure each carrier to perform HARQ-ACK feedback according to two transmission blocks. In our embodiment, the number of HARQ-ACK / NACK bits for each downlink time unit / downlink carrier is N1 or N2. Feedback indicates that the total number of bits for the two transmission blocks is N1 or N2. That is, the total number of bits for each transmission block is N1 / 2 or N2 / 2. The base station can configure N1 or N2 through signaling, or it can configure N1 / 2 or N2 / 2 through signaling. The specific manifestations of these two signaling configurations may be different, but the effect is the same.

[0230] According to another aspect of the invention, when generating the HARQ-ACK / NACK codebook, if the base station schedules only one PDSCH or only one PDSCH that meets predefined conditions, such as only the PDSCH scheduled on the Pcell and / or the PDSCH with DAI=1 of the first type, if the number c of the divisible coded block groups determined by the transport block size of the PDSCH is less than the maximum value N of the coded block groups configured by the base station, then the user terminal only feeds back c bits of HARQ-ACK / NACK or 2*c bits of HARQ-ACK / NACK, and when the number of fed back HARQ-ACK / NACK bits and / or the number of fed back HARQ-ACK / NACK bits and SR are less than or equal to a predefined threshold, such as when the threshold is 2, the user terminal will use a PUCCH format for carrying bit overhead not exceeding 2 to send HARQ-ACK / NACK, for example, similar to PUCCH format 1a / 1b in the LTE system. In other cases, such as when more than one PDSCH HARQ-ACK / NACK needs to be fed back and it is a semi-static codebook, the user terminal will determine the HARQ-ACK / NACK codebook based on N and the number of PDSCHs that need to be fed back for HARQ-ACK / NACK.

[0231] According to another aspect of the present invention, when generating the HARQ-ACK / NACK codebook, if at least two PDSCHs correspond to the same transport block within the same HARQ-ACK / NACK codebook, then the user terminal can determine the HARQ-ACK / NACK value according to one of the following two methods when generating the HARQ-ACK / NACK of the PDSCH:

[0232] - Method 1: For the same transport block, the HARQ-ACK / NACK bits of the last PDSCH in chronological order are generated according to the decoding result of the PDSCH, while the HARQ-ACK / NACK bit values ​​of all coded block groups of the preceding PDSCH are set to predefined values, such as NACK.

[0233] When the base station detects that some resources in the previous PDSCH transmission have been destroyed, it promptly retransmits a portion of the coded blocks of the same PDSCH. The situation described above occurs when both HARQ-ACK / NACK transmissions occur on the same PUCCH. This is because only the HARQ-ACK / NACK results generated by the user equipment for the second PDSCH transmission are meaningful, while the HARQ-ACK / NACK information for the previous PDSCH is redundant. Therefore, by setting all HARQ-ACK / NACK bits from the previous PDSCH transmission to NACK, PUCCH power can be saved. Furthermore, this method allows the base station to distinguish whether the user terminal missed detecting the last PDSCH when all HARQ-ACK / NACK bits of the subsequent PDSCH are NACK, or whether the user terminal found a situation where all coded blocks had correct CRC checks but the transport block had an incorrect CRC check during demodulation of the subsequent PDSCH. That is, if the user terminal misses the last PDSCH, the user will generate HARQ-ACK / NACK values ​​for the previous received PDSCH based on the actual demodulation results, and the HARQ-ACK / NACK values ​​for the next PDSCH will all be NACK; if there is a situation where the CRC check of all coded blocks is correct but the CRC check of the transport block is incorrect, the user will set the HARQ-ACK / NACK values ​​of all PDSCHs to NACK.

[0234] Accordingly, at the base station, a preferred implementation is to perform a bitwise OR operation on the HARQ-ACK / NACK bits of the two PDSCHs, group by group. That is, the two HARQ-ACK / NACK bits with the same transport block number are ORed; if either bit is ACK, it indicates that the transport block was received correctly. Of course, if the base station finds that the HARQ-ACK of the previous PDSCH is not all NACKs, and the HARQ-ACK of the subsequent PDSCH has at least one ACK, the base station can determine that a HARQ-ACK / NACK demodulation error may have occurred. The base station can then perform appropriate processing, such as rescheduling the transport block with the HARQ-ACK / NACK demodulation error.

[0235] For ease of explanation, we will use a single carrier as an example. For example... Figure 17As shown, carrier 1 is configured for HARQ-ACK / NACK feedback based on coded block groups, N1 = 4. Assume that all scheduled PDSCHs shown in the diagram correspond to the same PUCCH for HARQ-ACK feedback. The base station schedules the retransmission of transport block TB0 in time unit #0, schedules the initial transmission of transport block TB1 in time unit #1 (where the 3rd CBG is dropped by URLLC), schedules the retransmission of the 3rd CBG of transport block TB1 in time unit #3, and schedules the initial transmission of transport block TB2 in time unit #2. Assume the feedback method is based on the configured maximum number of coded blocks, i.e., N1 = 4. Assume the user terminal successfully detects the PDCCHs that schedule PDSCHs in the above four time units, then the final order of the HARQ-ACKs fed back by the user terminal is: 4 bits of TB0 in time unit #0, 4 bits of TB1 in time unit #1, 4 bits of TB2 in time unit #2, and 4 bits of TB1 in time unit #3. Assume the user terminal correctly demodulated TB0 and TB2, and correctly demodulated the 2nd and 4th coded block groups of TB1 in time unit #1, and also correctly demodulated the 3rd coded block group after receiving TB1 in time unit #3. According to existing technology, the feedback HARQ-ACK / NAKC bits would be AAAANANAAAANAAA. However, according to the method of this invention, the feedback HARQ-ACK / NACK bits are AAAANNNNAAAANAAA, meaning that even though the 2nd and 4th coded block groups of TB1 in time unit #1 were correctly demodulated, a NACK is still fed back because the feedback in time unit #3 already reflects the correct demodulation of the 2nd, 4th, and 3rd coded blocks. If the user terminal does not detect the PDCCH in time unit #3, then when the user terminal feeds back the ACK / NACK of TB1 in time unit #1, it should generate the total HARQ-ACK / NACK bits according to the demodulation result, i.e., the total feedback HARQ-ACK / NACK bits would be AAAANANAAAAANNNN. The base station can determine whether the user terminal has correctly demodulated the corresponding coded block group by performing a bitwise OR operation on multiple HARQ-ACK / NACK operations for the same TB. For example, in the following example, performing a bitwise OR operation on NANA of time unit #1 and NNNN of time unit #3 yields NANA. As another example, suppose the user terminal correctly demodulated TB0 and TB2, and correctly demodulated the 1st, 2nd, and 4th coded block groups of TB1 in time unit #1, and also correctly demodulated the 3rd coded block group after receiving TB1 in time unit #3. However, if the user terminal detects a transport block CRC error, then the feedback HARQ-ACK / NACK will be AAAANNNNAAAANNNN.Method 2: For the same transport block, the user terminal sets the HARQ-ACK / NACK values ​​of all received PDSCHs to the same value, which is generated based on the demodulation result of the last received PDSCH. If the user terminal receives multiple PDSCHs and finds that the CRC check of all coded blocks is correct but the CRC check of the transport block is incorrect, the user will set the HARQ-ACK / NACK of all PDSCHs to NACK. If the user terminal does not find an error in the CRC check of the transport block, the user terminal generates HARQ-ACK / NACK based on the demodulation result of the last received PDSCH, and sets the HARQ-ACK / NACK of the previously received PDSCHs to the same value as the HARQ-ACK / NACK of the last received PDSCH. Of course, if the user terminal does not detect some PDSCHs, but finds that a PDSCH was missed, then NACK is generated.

[0236] The advantage of this approach is that if the physical layer or MAC layer can only retain the last demodulated HARQ-ACK information for the same transport block, then it's natural to place the last demodulated HARQ-ACK result in the same HARQ-ACK bit position as the previous PDSCH. Of course, the physical layer might retain multiple PDSCH HARQ-ACK results for the same transport block, but setting the same value for the HARQ-ACK sent in the same PUCCH or PUSCH for the same transport block can increase the probability of the base station correctly receiving the HARQ-ACK.

[0237] like Figure 18As shown, carrier 1 is configured for HARQ-ACK / NACK feedback based on coded block groups, N1 = 4. Assume that all scheduled PDSCHs shown in the diagram correspond to the same PUCCH for HARQ-ACK feedback. The base station schedules the retransmission of transport block TB0 in time unit #0, schedules the initial transmission of transport block TB1 in time unit #1 (where the 3rd CBG is dropped by URLLC), schedules the retransmission of the 3rd CBG of transport block TB1 in time unit #3, and schedules the initial transmission of transport block TB2 in time unit #2. Assume the feedback method is based on the configured maximum number of coded blocks, i.e., N1 = 4. Assume the user terminal successfully detects the PDCCHs that schedule PDSCHs in the above four time units, then the final order of the HARQ-ACKs fed back by the user terminal is: 4 bits of TB0 in time unit #0, 4 bits of TB1 in time unit #1, 4 bits of TB2 in time unit #2, and 4 bits of TB1 in time unit #3. Assume the user terminal correctly demodulated TB0 and TB2, and correctly demodulated the second and fourth coded block groups of TB1 in time unit #1, and also correctly demodulated the third coded block group after receiving TB1 in time unit #3. According to the method of this invention, the feedback HARQ-ACK / NACK bits are AAAANAAAAAAANAAA, meaning that although the HARQ-ACK corresponding to TB1 in time unit #1 is fed back according to the HARQ-ACK of time unit #3. If the user terminal does not detect the PDCCH of time unit #3, then when the user terminal feeds back the ACK / NACK of TB1 in time unit #1, it should generate according to the demodulation result, that is, the total feedback HARQ-ACK / NACK bits are AAAANANAAAAANNNN. The base station can determine whether the user terminal has correctly demodulated the corresponding coded block group by performing a bitwise OR operation on multiple HARQ-ACK / NACKs of the same TB. For example, in the following example, the time unit...

[0238] The bitwise OR operation of NANA in time unit #1 and NNNN in time unit #3 yields NANA. For example, suppose the user terminal correctly demodulates TB0 and TB2, and correctly demodulates the 1st, 2nd, and 4th coded block groups of TB1 in time unit #1, and also correctly demodulates the 3rd coded block group after receiving TB1 in time unit #3. However, if the user terminal detects a transport block CRC error, then the feedback HARQ-ACK / NACK will be AAAANNNNAAAANNNN.

[0239] In the above examples, the last PDSCH described refers to the PDSCH that the user terminal can demodulate and generate a HARQ-ACK based on the demodulation result before feeding back a HARQ-ACK on the PUCCH / PUSCH. Typically, if the base station schedules the HARQ-ACK of the PDSCH to be uploaded to a certain PUCCH or PUSCH, the base station will ensure that the time difference from the PDSCH to the PUCCH / PUSCH is not less than the processing latency of the user terminal, meaning the user terminal has sufficient time to demodulate the PDSCH and generate the corresponding HARQ-ACK. However, in some implementations, if the time difference mentioned by the base station is less than the processing latency of the user terminal, then such a PDSCH HARQ-ACK can feed back a NACK, or copy the HARQ-ACK of the previous PDSCH generated based on the demodulation result.

[0240] In the above embodiments, the uplink / downlink time unit can be a time slot or a mini-time slot. For example, the downlink time unit for receiving downlink data is a time slot, and the uplink time unit for its HARQ-ACK / NACK feedback is also a time slot; or the downlink time unit for receiving downlink data is a mini-time slot, and the uplink time unit for its HARQ-ACK / NACK feedback is also a mini-time slot; or the downlink time unit for receiving downlink data is a time slot, and the uplink time unit for its HARQ-ACK / NACK feedback is a mini-time slot; or the downlink time unit for receiving downlink data is a mini-time slot, and the uplink time unit for its HARQ-ACK / NACK feedback is a time slot. The uplink / downlink time unit can be determined as a time slot or a mini-time slot through higher-layer configuration or predefined rules, or it can be indicated by dynamic signaling.

[0241] The methods described in the above embodiments can also be applied to carrier aggregation, i.e., when the base station configures multiple serving cells for the user terminal. Accordingly, when determining the HARQ-ACK / NACK codebook size, it is necessary to determine the number of HARQ-ACK / NACK bits for each carrier using the method according to the present invention, and also to determine the total number of HARQ-ACK / NACK bits and the mapping method based on the configured multiple serving cells. For example, in the second exemplary embodiment of the present invention, the total number of HARQ-ACK / NACK bits for each carrier is determined based on the feedback window size, and then the total number of bits in the HARQ-ACK / NACK codebook for all carriers and all downlink time units, and the HARQ-ACK / NACK bit mapping, are determined based on the number of carriers.

[0242] In the above embodiments, when it is uncertain whether the user terminal and the base station have a consistent understanding of certain configurations, such as the HARQ-ACK / NACK feedback configuration, or when the base station has not yet configured the user terminal for HARQ-ACK / NACK feedback, the base station can schedule the user terminal to work in a fallback mode to ensure that the base station and the user terminal have a consistent understanding of the HARQ-ACK / NACK codebook. For example, before the base station sends higher-layer control signaling for determining the HARQ-ACK / NACK codebook, or before the base station determines that the user terminal has correctly received the higher-layer control signaling for determining the HARQ-ACK / NACK codebook, the base station can schedule the user terminal to work in the fallback mode. For example, in the first exemplary embodiment, when the base station has not semi-statically configured the HARQ-ACK / NACK codebook size, the base station can schedule the feedback of HARQ-ACK / NACK for only one downlink time unit in one uplink time unit, and the user terminal can provide feedback according to the HARQ-ACK / NACK for one time unit. For example, in a third exemplary embodiment, before determining that the user terminal has correctly received the higher-layer control signaling configuring HARQ-ACK / NACK based on either a coded block group or a transport block, the base station can schedule HARQ-ACK / NACK for a PDSCH that only feeds back one downlink time unit of a carrier within an uplink time unit. Furthermore, the downlink control signaling that schedules the PDSCH uses downlink control information in a back-off mode, meaning that both the PDSCH scheduled by the signaling and the HARQ-ACK / NACK feedback for the PDSCH are on a transport block basis. In this way, the user terminal only feeds back N2 bits of HARQ-ACK / NACK, for example, N2 = 1, and the user terminal can use a PUCCH format for carrying lower overhead to send HARQ-ACK / NACK, for example, similar to PUCCH format 1a / 1b in an LTE system. The advantage of this is that when the base station reconfigures the scheduling / feedback mode based on the coding block group or reconfigures N1 in the scheduling / feedback mode based on the coding block group, the user may not be able to determine the overhead of the downlink control signaling or PUCCH, but the user can determine the overhead of the downlink control signaling in the fallback mode and the PUCCH corresponding to its scheduled PDSCH.

[0243] Figure 14 This is a flowchart of the downlink transmission method according to the present invention. Here, the downlink transmission is performed by the base station.

[0244] Reference Figure 14 In step 1401, the base station configures control signaling.

[0245] In step 1402, the base station sends a PDSCH and control signaling to the user equipment in the downlink time unit. Here, the control signaling can be used to determine at least one of the following for the user equipment to feed back: the uplink time unit of the HARQ-ACK / NACK corresponding to the PDSCH, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the position of the HARQ-ACK / NACK corresponding to each downlink time unit of the uplink time unit in the HARQ-ACK / NACK codebook.

[0246] According to an exemplary embodiment, the control signaling may be downlink scheduling signaling carried by PDCCH or control signaling carried by PDSCH.

[0247] According to an exemplary embodiment, the control signaling may include information about the timing of HARQ-ACK / NACK.

[0248] According to an exemplary embodiment, the information regarding HARQ-ACK / NACK timing can be one of the following: information indicating the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback; information indicating one or more uplink time units containing configured PUCCHs that are greater than or equal to the minimum time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback, and are closest to the minimum time difference; information indicating whether the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback is predefined, or whether the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback is predefined, and is closest to the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback, and is one or more uplink time units containing configured PUCCHs.

[0249] According to an exemplary embodiment, the control signaling may further include a first type of DAI, wherein the first type of DAI indicates one of the following: the relative time order of the currently scheduled downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the bit position of the HARQ-ACK / NACK bit of the currently scheduled downlink time unit in the HARQ-ACK / NACK codebook. When the UE is configured for carrier aggregation, the first type of DAI may be counted separately for each carrier, as in the DAI of downlink control signaling in existing LTE Rel-8 TDD systems; or, the first type of DAI may be frequency-first, then time-second, i.e., counting is performed on each scheduled carrier in the same time unit and then on each scheduled carrier in the next time unit, as in the DAI of downlink control signaling in existing LTE Rel-13 carrier aggregation systems. The first type of DAI can be used to dynamically determine the HARQ-ACK codebook or to semi-statically determine the HARQ-ACK codebook.

[0250] According to an exemplary embodiment, in the control signaling, the first type of DAI can be co-encoded with information about HARQ-ACK / NACK timing.

[0251] According to an exemplary embodiment, the control signaling may further include a second type of DAI, wherein the second type of DAI indicates one of the following information: the total number of downlink time units of all scheduled downlink time units corresponding to the uplink time unit, the total number of downlink time units from the first downlink time unit to the current downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the total number of bits of the HARQ-ACK / NACK codebook indicated by the second type of DAI.

[0252] According to an exemplary embodiment, in the control signaling, the first type DAI, the second type DAI, and information regarding HARQ-ACK / NACK timing can be jointly encoded.

[0253] According to an exemplary embodiment, the control signaling may further include information indicating that the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on the maximum number of transport blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded block groups that can be transmitted in each downlink time unit.

[0254] According to an exemplary embodiment, the control signaling may further include the size of a HARQ-ACK / NACK codebook configured by the base station.

[0255] According to an exemplary embodiment, the control signaling may further include information indicating a time unit in which PDSCH is definitely not sent.

[0256] According to an exemplary embodiment, when the total number of uplink control signaling bits that need to be fed back in the uplink time unit exceeds the maximum number of uplink control signaling bits that the PUCCH resources configured by the base station can carry, the base station may send new downlink scheduling information of PUCCH resources capable of carrying the total number of uplink control signaling bits that need to be fed back to the user equipment in the current downlink time unit or in at least the last downlink time unit corresponding to the uplink time unit.

[0257] Figure 15 This is a block diagram of a device 1500 for transmitting HARQ-ACK / NACK according to the present invention. Here, user equipment can use the device 1500 for transmitting HARQ-ACK / NACK to transmit HARQ-ACK / NACK.

[0258] Reference Figure 15 The device 1500 for sending HARQ-ACK / NACK may include a receiving unit 1501, a determining unit 1502, a generating unit 1503, and a sending unit 1504.

[0259] Specifically, the receiving unit 1501 can receive PDSCH and control signaling from the base station in the downlink time unit.

[0260] Next, the determining unit 1502 can determine, based on the control signaling, the uplink time unit for feeding back the HARQ-ACK / NACK corresponding to the received PDSCH, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook.

[0261] Next, the generation unit 1503 can generate the HARQ-ACK / NACK codebook based on the size of the HARQ-ACK / NACK codebook and the position of the HARQ-ACK / NACK corresponding to each downlink time unit in the HARQ-ACK / NACK codebook.

[0262] Finally, the transmitting unit 1504 can transmit the generated HARQ-ACK / NACK codebook in the uplink time unit.

[0263] The device 1500 for sending HARQ-ACK / NACK can implement the various exemplary embodiments of the present invention described above through a receiving unit 1501, a determining unit 1502, a generating unit 1503, and a sending unit 1504. The receiving unit 1501, the determining unit 1502, the generating unit 1503, and the sending unit 1504 can respectively implement the corresponding functions in the various embodiments described in detail above. For detailed functions, please refer to the various embodiments described above; detailed descriptions of them will be omitted here.

[0264] Figure 16 This is a block diagram of the downlink transmission device 1600 according to the present invention. Here, the base station can use the downlink transmission device 1600 of the present invention to perform downlink transmission.

[0265] Reference Figure 16 The downlink transmission device 1600 may include a configuration unit 1601 and a transmission unit 1602.

[0266] Specifically, configuration unit 1601 configures control signaling.

[0267] The transmitting unit 1602 transmits PDSCH and control signaling to the user equipment in the downlink time unit. Here, the control signaling can be used to determine at least one of the following for the user equipment to provide feedback: the uplink time unit of HARQ-ACK / NACK corresponding to the PDSCH, the size of the HARQ-ACK / NACK codebook corresponding to the uplink time unit, and the position of the HARQ-ACK / NACK corresponding to each downlink time unit of the uplink time unit in the HARQ-ACK / NACK codebook.

[0268] According to an exemplary embodiment, the control signaling may be downlink scheduling signaling carried by PDCCH or control signaling carried by PDSCH.

[0269] According to an exemplary embodiment, the control signaling may include information about the timing of HARQ-ACK / NACK.

[0270] According to an exemplary embodiment, the information regarding HARQ-ACK / NACK timing can be one of the following: information indicating the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback; information indicating one or more uplink time units containing configured PUCCHs that are greater than or equal to the minimum time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback, and are closest to the minimum time difference; information indicating whether the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback is predefined, or whether the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback is predefined, and is closest to the time difference between the downlink time unit where the PDSCH is located and the uplink time unit that provides the HARQ-ACK / NACK feedback, and is one or more uplink time units containing configured PUCCHs.

[0271] According to an exemplary embodiment, the control signaling may further include a first type of DAI, wherein the first type of DAI indicates one of the following information: the relative time order of the currently scheduled downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the bit position of the HARQ-ACK / NACK bit of the currently scheduled downlink time unit in the HARQ-ACK / NACK codebook.

[0272] According to an exemplary embodiment, in the control signaling, the first type of DAI can be co-encoded with information about HARQ-ACK / NACK timing.

[0273] According to an exemplary embodiment, the control signaling may further include a second type of DAI, wherein the second type of DAI indicates one of the following information: the total number of downlink time units of all scheduled downlink time units corresponding to the uplink time unit, the total number of downlink time units from the first downlink time unit to the current downlink time unit among all scheduled downlink time units corresponding to the uplink time unit, and the total number of bits of the HARQ-ACK / NACK codebook indicated by the second type of DAI.

[0274] According to an exemplary embodiment, in the control signaling, the first type DAI, the second type DAI, and information regarding HARQ-ACK / NACK timing can be jointly encoded.

[0275] According to an exemplary embodiment, the control signaling may further include information indicating that the number of HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on the maximum number of transport blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded blocks that can be transmitted in each downlink time unit, or based on the maximum number of coded block groups that can be transmitted in each downlink time unit.

[0276] According to an exemplary embodiment, the control signaling may further include the size of a HARQ-ACK / NACK codebook configured by the base station.

[0277] According to an exemplary embodiment, the control signaling may further include information indicating a time unit in which PDSCH is definitely not sent.

[0278] According to an exemplary embodiment, when the total number of uplink control signaling bits that need to be fed back in the uplink time unit exceeds the maximum number of uplink control signaling bits that the PUCCH resources configured by the base station can carry, the sending unit 1602 may send new downlink scheduling information of PUCCH resources that can carry the total number of uplink control signaling bits that need to be fed back to the user equipment in the current downlink time unit or in at least the last downlink time unit corresponding to the uplink time unit.

[0279] According to the method and apparatus for user equipment to send HARQ-ACK / NACK and the method and apparatus for base station to send HARQ according to the present invention, when the HARQ-ACK feedback time is variable, the user equipment can accurately determine the size of the HARQ-ACK codebook and the bit mapping, and the uplink control channel resources can be effectively utilized.

[0280] The above description is only a partial embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method performed by a user equipment in a wireless communication system, the method comprising: A first set of timing values, comprising at least one hybrid automatic repeat request-acknowledgment / negation (HARQ-ACK / NACK), is determined based on at least one of higher-layer signaling and predefined configurations, wherein each timing value in the first set indicates the time difference between a downlink time unit for receiving the Physical Downlink Shared Channel (PDSCH) and an uplink time unit for sending HARQ-ACK / NACK feedback. Based on the first set, a second set is determined, which includes at least one downlink time unit for PDSCH reception; The codebook for the HARQ-ACK / NACK feedback is generated based on the codebook size, wherein the codebook size is determined based on the number of one or more HARQ-ACK / NACK bits corresponding to each downlink time unit included in the second set; Send the codebook to the base station. In the case where downlink transmission scheduling is based on coded block groups (CBGs), the number of one or more HARQ-ACK / NACK bits is determined based on the maximum number of CBGs in a transport block (TB).

2. The method as described in claim 1, wherein, The HARQ-ACK / NACK for each downlink time unit included in the second set is sent in a single uplink time unit. The codebook is transmitted within the single uplink time unit.

3. The method as described in claim 1, wherein, The determination includes a second set comprising at least one downlink time unit for PDSCH reception, comprising: The following time units are included in the second set: the time difference between the time unit and the uplink time unit is a value in the first set; Remove the time units configured as uplink time units from the second set.

4. The method of claim 3, wherein, The size of the codebook is determined after removing at least one time unit configured as an uplink time unit from the second set.

5. The method of claim 1, wherein, The number of one or more HARQ-ACK / NACK bits is determined based on at least one parameter received from the base station via the higher-layer signaling. The at least one parameter includes at least one of the following: the maximum number of TBs in each downlink time unit or the maximum number of CBGs in a TB.

6. The method of claim 1, wherein, When space binding is disabled and scheduling is based on TB, the number of one or more HARQ-ACK / NACK bits is determined based on 2 bits.

7. The method of claim 1, wherein, When spatial binding is enabled, the number of one or more HARQ-ACK / NACK bits is determined based on 1 bit.

8. The method of claim 1, further comprising: Downlink control information (DCI) is received from the base station, wherein the DCI includes one or more bits indicating a value in the first set. The value indicates the time difference between the downlink time unit and the uplink time unit in which the PDSCH scheduled by the DCI is received. The HARQ-ACK / NACK results for the PDSCH are included in the codebook.

9. A user equipment in a wireless communication system, the user equipment comprising: transceiver; At least one controller, coupled to the transceiver, is configured to: A first set of timing values, comprising at least one hybrid automatic repeat request-acknowledgment / negation (HARQ-ACK / NACK), is determined based on at least one of higher-layer signaling and predefined configurations, wherein each timing value in the first set indicates the time difference between a downlink time unit for receiving the Physical Downlink Shared Channel (PDSCH) and an uplink time unit for sending HARQ-ACK / NACK feedback. Based on the first set, a second set is determined, which includes at least one downlink time unit for PDSCH reception; The codebook for the HARQ-ACK / NACK feedback is generated based on the codebook size, wherein the codebook size is determined based on the number of one or more HARQ-ACK / NACK bits corresponding to each downlink time unit included in the second set; Send the codebook to the base station. In the case where downlink transmission scheduling is based on coded block groups (CBGs), the number of one or more HARQ-ACK / NACK bits is determined based on the maximum number of CBGs in a transport block (TB).

10. The user equipment as claimed in claim 9, wherein, The HARQ-ACK / NACK for each downlink time unit included in the second set is sent in a single uplink time unit. The codebook is transmitted within the single uplink time unit.

11. The user equipment as claimed in claim 9, wherein, The at least one controller is configured to: The following time units are included in the second set: the time difference between the time unit and the uplink time unit is a value in the first set; Remove the time units configured as uplink time units from the second set.

12. The user equipment as claimed in claim 11, wherein, The size of the codebook is determined after removing at least one time unit configured as an uplink time unit from the second set.

13. The user equipment as claimed in claim 9, wherein, The number of one or more HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on at least one parameter received from the base station via the higher-layer signaling. The at least one parameter includes at least one of the following: the maximum number of TBs in each downlink time unit or the maximum number of CBGs in a TB.

14. The user equipment as claimed in claim 9, wherein, When spatial binding is disabled and scheduling is based on TB, the number of one or more HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on 2 bits.

15. The user equipment as claimed in claim 9, wherein, When spatial binding is enabled, the number of one or more HARQ-ACK / NACK bits corresponding to each downlink time unit is determined based on 1 bit.

16. The user equipment of claim 9, wherein the at least one controller is further configured to: Downlink control information (DCI) is received from the base station, wherein... The DCI includes one or more bits indicating a value in the first set. The value indicates the time difference between the downlink time unit and the uplink time unit in which the PDSCH scheduled by the DCI is received. The HARQ-ACK / NACK results for the PDSCH are included in the codebook.

17. A method performed by a base station in a wireless communication system, the method comprising: PDSCH is transmitted in a second set including at least one downlink time unit for receiving the Physical Downlink Shared Channel (PDSCH); Receive codebooks for Hybrid Automatic Repeat Request-Acknowledge / Negative HARQ-ACK / NACK feedback; The size of the codebook is determined based on the number of one or more HARQ-ACK / NACK bits corresponding to each downlink time unit included in the second set. The second set is determined based on a first set that includes at least one HARQ-ACK / NACK timing value. The first set is determined based on at least one of higher-level signaling and predefined configurations. Each timing value in the first set indicates the time difference between the downlink time unit for PDSCH reception and the uplink time unit for sending HARQ-ACK / NACK feedback. In the case where downlink transmission scheduling is based on coded block groups (CBGs), the number of one or more HARQ-ACK / NACK bits is determined based on the maximum number of CBGs in a transport block (TB).

18. The method of claim 17, wherein, The HARQ-ACK / NACK for each downlink time unit included in the second set is sent in a single uplink time unit. The codebook is transmitted within the single uplink time unit.

19. The method of claim 17, wherein, The second set was determined based on the following method: The following time units are included in the second set: the time difference between the time unit and the uplink time unit is a value in the first set; Remove the time units configured as uplink time units from the second set.

20. The method of claim 19, wherein, The size of the codebook is determined after removing at least one time unit configured as an uplink time unit from the second set.

21. The method of claim 17, wherein, The number of one or more HARQ-ACK / NACK bits is determined based on at least one parameter received from the base station via the higher-layer signaling. The at least one parameter includes at least one of the following: the maximum number of TBs in each downlink time unit or the maximum number of CBGs in a TB.

22. The method of claim 17, wherein, When space binding is disabled and scheduling is based on TB, the number of one or more HARQ-ACK / NACK bits is determined based on 2 bits.

23. The method of claim 17, wherein, When spatial binding is enabled, the number of one or more HARQ-ACK / NACK bits is determined based on 1 bit.

24. The method of claim 17, further comprising: Sending downlink control information (DCI) to the user equipment, wherein the DCI includes one or more bits indicating a value in the first set. The value indicates the time difference between the downlink time unit and the uplink time unit in which the PDSCH scheduled by the DCI is received. The HARQ-ACK / NACK results for the PDSCH are included in the codebook.

25. A base station in a wireless communication system, the base station comprising: transceiver; At least one controller, coupled to the transceiver, is configured to perform the method described in any one of claims 17 to 24.

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