Method, device and system for triggering feedback confirmation of wireless downlink communication resource allocation

Abstract

The present disclosure describes embodiments of a modified ARQ / HARQ process that deviates from the normal wait-for-stop ARQ / HARQ process. In particular, a series of messages to be sent can be organized into a predetermined number of message groups. By using various control parameters communicated between a transmitting device and a receiving device, different message groups can be sent independently without having to wait for an acknowledgment of one message group before sending another. Additionally, in each of the message groups, the receiving device is allowed to store and hold the acknowledgments of the messages until a later time specified by a control parameter sent via a control message. The control message can trigger the transmission of the stored acknowledgments of one or more message groups, which are also identified by the control parameters included in the control message. Multiple outstanding acknowledgments of multiple message groups can be triggered and subsequently sent in a single acknowledgment message. The outstanding acknowledgments can include acknowledgments for successfully receiving both initially sent messages and retransmitted messages.

Description

Technical Field

[0001] The present disclosure relates to the aggregation, grouping, and transmission of acknowledgement feedback for wireless communication messages in an Automatic Repeat reQuest (ARQ) or Hybrid ARQ (HARQ) process. Background Art

[0002] Wireless communication technologies are driving the world towards rapidly growing network connectivity. High-speed and low-latency wireless communication relies on efficient network resource management and allocation between user equipment and wireless access network nodes, including but not limited to wireless base stations. Wireless communication between user equipment and a wireless base station can be carried by communication resources allocated in both radio frequency and time. Wireless communication can be achieved by sending and receiving wireless messages. Due to channel quality defects and fluctuations in communication resources, the sent wireless messages may be lost or corrupted and cannot be corrected. These lost or corrupted messages may be automatically retransmitted. The correct design of control mechanisms for detecting and retransmitting lost or corrupted messages can help improve the efficiency of the wireless access network, especially for accessing unlicensed shared radio frequency bands where government agencies may impose additional licensing. Summary of the Invention

[0003] The present disclosure describes embodiments of a modified ARQ / HARQ process that deviates from the normal wait-and-stop ARQ / HARQ process. In particular, a series of messages to be sent can be organized into a predetermined number of message groups. By using various control parameters transmitted between a sending device and a receiving device, different message groups can be transmitted independently without having to wait for the acknowledgement of one group of messages before transmitting another group. Additionally, within each of the message groups, the receiving device is allowed to store and maintain the acknowledgement of the messages until a later time specified by control parameters sent via a control message. The control message can trigger the transmission of the stored acknowledgements for one or more message groups, which are also identified by the control parameters included in the control message. Multiple outstanding acknowledgements for multiple message groups can be triggered and subsequently sent in a single acknowledgement message. The outstanding acknowledgements can include acknowledgements of successful reception for both initially sent messages and retransmitted messages.

[0004] In one embodiment, a method for triggering feedback on communication resource allocation from a wireless device, performed by a wireless access node, is disclosed. The method may include: generating a downlink control message that includes a set of wireless downlink communication resource allocations, and a plurality of allocation feedback control fields, the plurality of allocation feedback control fields including: a resource group ID field, a feedback trigger group indicator, and a feedback timing indicator, the resource group ID field identifying a current allocation group among a plurality of allocation groups for the set of wireless downlink communication resource allocations; the feedback trigger group indicator specifying a set of trigger allocation groups among the plurality of allocation groups for which the wireless device will be triggered to provide feedback; and the feedback timing indicator specifying timing control information for triggering feedback from the wireless device. The method further includes: sending the downlink control message to the wireless device to control the wireless device to provide feedback on all outstanding and unacknowledged wireless downlink communication resource allocations belonging to the set of trigger allocation groups, according to the feedback timing indicator.

[0005] In the above embodiment, the timing control information in the feedback timing indicator of the downlink control message may include a non-numerical value that is used to indicate to the wireless device to delay providing feedback until at least the next downlink control message having a numerical feedback timing indicator field. Additionally, the number of times the feedback timing indicator of the next downlink control message having the resource group ID field as the current allocation group is non-numerical may be limited to a predefined maximum number before all outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group are acknowledged by the wireless device. Alternatively, in the above embodiment, the timing control information in the feedback timing indicator of the downlink control message includes a numerical value for specifying a future time slot in which the wireless device will provide feedback.

[0006] In any of the above embodiments, the plurality of allocation feedback control fields of the downlink control message may further include an allocation feedback status field that is used to indicate whether there are any outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group, in addition to the set of wireless downlink communication resource allocations included in the downlink control message. Additionally, the allocation feedback status field may be determined by a handover bit maintained for the current allocation group. The handover bit for the current allocation group may be configured to switch when an acknowledgment of all outstanding and unacknowledged allocations in the current allocation group is received.

[0007] In any of the above embodiments, the method may further include maintaining a separate numbered index for each of the plurality of allocation groups for outstanding and unacknowledged radio communication resource allocations. The plurality of allocation feedback control fields of the downlink control message may further include a separate numbered index for a set of radio downlink communication resource allocations included in the downlink control message. The method may further include maintaining a separate total cumulative count for each of the plurality of allocation groups for outstanding and unacknowledged radio communication resource allocations. Additionally, the plurality of allocation feedback control fields of the downlink control message may further include a separate total cumulative count for outstanding and unacknowledged radio communication resource allocations in the current allocation group identified by the resource group ID field of the downlink control message. Further, the plurality of allocation feedback control fields of the downlink control message may include a separate total cumulative count for outstanding and unacknowledged radio communication resource allocations for an allocation group specified by the feedback trigger group indicator of the downlink control message. The plurality of allocation feedback control fields of the downlink control message may further include a single total cumulative count for outstanding and unacknowledged radio communication resource allocations accumulated among all allocation groups specified by the feedback trigger group indicator of the downlink control message.

[0008] In any of the above embodiments, the feedback for all outstanding and unacknowledged allocations from the wireless device includes a feedback bitmap that includes a single bit for each of all outstanding and unacknowledged allocations as an acknowledgment or non-acknowledgment indicator. The method may further include retransmitting radio downlink communication resource allocations having a non-acknowledgment indicator in the feedback bitmap using another downlink control message.

[0009] In another embodiment, a method performed by a wireless device is disclosed for providing feedback on an allocation of radio downlink communication resources sent from a radio access node. The method may include: receiving a downlink control message from the radio access node, the downlink control message including a set of radio downlink communication resource allocations, a plurality of allocation feedback control fields including a resource group ID field, a feedback trigger group indicator, and a feedback timing indicator, the resource group ID field identifying a current allocation group among a plurality of allocation groups for the set of radio downlink communication resource allocations; the feedback trigger group indicator specifying a set of trigger allocation groups among the plurality of allocation groups for which the wireless device will be triggered to provide feedback; the feedback timing indicator specifying timing control information for triggering feedback from the wireless device. The method may further include: providing feedback on all outstanding and unacknowledged radio downlink communication resource allocations belonging to the set of trigger allocation groups according to the feedback timing indicator.

[0010] In the above embodiments, the method may further include: when determining that the feedback timing indicator of the downlink control message includes a non-numerical value indicating delayed feedback to the wireless device, generating a first feedback data item corresponding to all outstanding and unacknowledged wireless downlink communication resource allocations belonging to a set of trigger allocation groups; and storing the first feedback data item in a repository for maintaining outstanding allocation feedback. Alternatively, the method may include, when determining that the feedback timing indicator of the downlink control message includes a numerical value specifying a future time slot, transmitting all outstanding and unacknowledged wireless downlink communication resource allocations belonging to a set of trigger allocation groups in the future time slot.

[0011] In any of the above methods performed by a wireless device, the plurality of allocation feedback control fields of the downlink control message further includes an allocation feedback status field for indicating whether there are any outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group in addition to the set of wireless downlink communication resource allocations included in the downlink control message. The method may further include a method that includes: when the allocation feedback status field of the downlink control message indicates that there are no outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group, removing the feedback data item stored in the repository associated with the current allocation group.

[0012] In another embodiment, a method for sending an uplink message from a mobile device to a radio access node is disclosed. The method may include: identifying a plurality of frequency resource blocks within an uplink transmission band, where the plurality of frequency resource blocks are scattered across the uplink transmission band; and modulating the uplink message into the plurality of frequency resource blocks as an interleaving that includes one of the following: the same base sequence with a cyclic shift having a cycle among the plurality of frequency resource blocks, the same base sequence with different phase rotations among the plurality of frequency resource blocks, different base sequences or sequence group numbers among the plurality of frequency resource blocks, or subsequences of a long sequence among the plurality of frequency resource blocks.

[0013] In another embodiment, a method for sending a downlink message from a radio access network to a mobile device is disclosed. The method may include: determining the symbol length of the downlink message; and mapping the downlink message using type B mapping of 5G New Radio, where the position of the demodulation reference symbol (DMRS) in the downlink message is based on the DMRS symbol position for type A downlink transmission of data of the same symbol length in 5G New Radio or based on the DMRS symbol position for type B uplink transmission of that symbol length in 5G New Radio.

[0014] In yet another embodiment, a method for sending a downlink message from a radio access network to a mobile device is disclosed. The method may include: determining a symbol length of the downlink message; mapping the downlink message using a type B mapping of 5G new radio; including only single-symbol precoded DMRS when the symbol length is 7 or less; and including DMRS at the precoding position and position symbol 4, or at the precoding position, position symbol 4, and position symbol 7 when the symbol length is greater than 7.

[0015] The above embodiments and other aspects and alternatives of their implementations are described in more detail below in the drawings, the specification, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A radio access network with exemplary uplink, downlink, and control channel configurations is shown.

[0017] Figure 2 An exemplary portion of a data field in a downlink control information (DCI) message sent from a base station to a user equipment is shown, where the downlink control information (DCI) message is for allocating communication resources and for configuring an automatic repeat request (ARQ) or hybrid ARQ (HARQ) process.

[0018] Figure 3 An exemplary time slot stream of a series of DCI messages sent and automatically retransmitted by a base station, and corresponding acknowledgment and non-acknowledgment feedback in the form of uplink control information (UCI) messages sent by the user equipment for allocating and acknowledging multiple downlink communication resource groups are shown.

[0019] Figure 4 Shows Figure 3 A specific implementation of the time slot stream, which has various exemplary data field specifications in a DCI message for allocating communication resources and controlling the HARQ process.

[0020] Figure 5 Shows Figure 3 Another specific implementation of the time slot stream, which has various exemplary data field specifications in a DCI message for allocating communication resources and controlling the HARQ process.

[0021] Figure 6 Shows Figure 3 Another specific implementation of the time slot stream, which has various exemplary data field specifications in a DCI message for allocating communication resources and controlling the HARQ process.

[0022] Figure 7illustrates Figure 3 Another specific embodiment of the time slot stream of Figure 3 , which has various exemplary data field specifications in the DCI message for allocating communication resources and controlling the HARQ process.

[0023] Figure 8 Illustrates an exemplary embodiment for tracking the allocation of a single set of communication resources using the downlink assignment index (DAI) data field in the DCI message.

[0024] Figure 9 Illustrates an exemplary embodiment for tracking the allocation of multiple sets of communication resources using the DAI data field in the DCI message.

[0025] Figure 10 Illustrates another exemplary embodiment for tracking the allocation of multiple sets of communication resources using the DAI data field in the DCI message. Specific embodiment

[0026] The radio frequency spectrum provides the basic communication resources and information carrier for the radio access network. This radio frequency spectrum can be divided into reserved radio frequency bands, licensed radio frequency bands, and unlicensed radio frequency bands. The spectrum designations for these reserved radio bands, licensed radio bands, and unlicensed radio bands by government agencies may vary in different countries and / or geographical regions. Most of the radio frequency spectrum applicable to wireless communication is either reserved for special purposes (e.g., for military use) or licensed, leaving only a few isolated unlicensed bands for commercial systems and applications. For example, the common global unlicensed part of the radio frequency spectrum may include, but is not limited to, radio frequency bands near 2.4 GHz, 5 GHz, and 60 GHz. These unlicensed radio frequency bands can be used commercially, but must be shared by various radio access systems and applications to ensure the fair and harmonious coexistence of these radio access systems. Since these unlicensed radio frequency bands are globally available, they can provide the global mobility required by many types of devices (such as cellular phones).

[0027] For communication between two terminal devices in both licensed and unlicensed radio frequency bands (e.g., between a user equipment (UE) and a radio access node (alternatively referred to as a radio base station)), an automatic repeat request (ARQ) process can be used for the receiving end to confirm the error-free reception of a message sent by the sending end (e.g., via error detection determination), and for the sending end to repeat the transmission of the message if such confirmation is not received within the duration of one of the specific predefined time windows. In addition to error detection by the receiving end, a hybrid ARQ (HARQ) process can also be implemented for forward error correction, such that in the presence of correctable transmission errors, confirmation can be provided to the sending end, or in the case where the message is uncorrectable, the sending end can automatically retransmit only the information required to correct the message, rather than retransmitting the entire message.

[0028] Several adaptations and modifications to existing ARQ / HARQ processes and signaling formats may be desirable, especially for communication in unlicensed radio frequency bands. For example, confirmations from some receiving devices (such as UEs) may not be available during the channel occupancy period of the sent message, and may be significantly delayed due to their relatively limited processing capabilities in decoding and further error detection and correction of the message before generating and sending the confirmation in certain frequency bands. In such cases, the stop-and-wait process used in normal ARQ / HARQ processes may be very inefficient. Thus, it may be necessary to design the scheduling of the transmission of a series of messages and the determination of the timing of the transmission of confirmations in a flexible and efficient manner in unlicensed radio frequency bands. Accordingly, the control and signaling information exchanged between the sending end and the receiving end can also be designed to support such flexibility in unlicensed radio frequency bands.

[0029] As another example, a communication channel or resource allocation scheme for sending general messages, and in particular acknowledgment messages, typically in an unlicensed frequency band may also need to be modified according to a communication channel or resource allocation scheme for an authorized radio frequency band. Specifically, channel access and sharing of the unlicensed radio frequency band by systems operating under various different radio access protocol stacks can be based on schemes such as listen-before-talk (LBT) introduced in the License-Assisted-Access (LAA) procedure of a Long Term Evolution (LTE) system and the Clear Chanel Assessment (CCA) procedure used in IEEE 802.11. In other words, the communication channel must be cleared before sending data. To accurately detect channel activation (or deactivation) during the channel listening and assessment phases, according to regulatory policies, it may be mandatory for messages (including acknowledgment messages in the ARQ / HARQ procedure) to occupy a sufficiently large portion of a specific channel bandwidth unit or be spread over a sufficiently large portion of a specific channel bandwidth unit (e.g., for a 20 MHz channel bandwidth in the unlicensed frequency band around 5 GHz, at least 70% or 80%). Since channel deactivation detection is required before using a channel in the unlicensed radio frequency band in a shared environment, this requirement will correspondingly require modification of the communication of messages for resource allocation and acknowledgment feedback (such as acknowledgment messages containing ARQ and HARQ information).

[0030] The present disclosure describes embodiments of a modified ARQ / HARQ procedure that deviates from the normal wait-and-stop ARQ / HARQ procedure. In particular, a series of messages to be sent can be organized into a predetermined number of message groups. By using various control parameters communicated between a transmitting device and a receiving device, different message groups can be transmitted independently without having to wait for the acknowledgment of one group of messages for the transmission of another group of messages. Further, in each of the message groups, the receiving device is allowed to store and hold the acknowledgment of the messages until a later time specified by a control parameter sent via a control message. The control message can trigger the transmission of the stored acknowledgments for one or more message groups, which are also identified by the control parameters included in the control message. Multiple outstanding acknowledgments for multiple message groups can be triggered and subsequently sent in a single acknowledgment message. The outstanding acknowledgments can include acknowledgments for successful reception of both initially transmitted messages and retransmitted messages.

[0031] In the context of a radio access network environment as shown in Figure 1 the basic principles of the present disclosure are shown below and in the corresponding Figures 2 to 10 In Figure 1In a wireless access network 100, it includes a base station 102 and a user equipment (UE) 104, which communicate with each other via over-the-air (OTA) radio communication resources 106. The wireless access network 100 can be implemented as, for example, a 2G, 3G, 4G / LTE or 5G cellular wireless access network. Correspondingly, the base station 102 can be implemented as a 2G base station, a 3G Node B, an LTE eNB or a 5G New Radio (NR) gNB. The user equipment 104 can be implemented as a mobile or fixed communication device equipped with a SIM module for accessing the base station 102. The user equipment 104 can include, but is not limited to, mobile phones, laptops, tablets, personal digital assistants, wearable devices, distributed remote sensor devices and desktop computers. Alternatively, the wireless access network 100 can be implemented as other types of wireless access networks, such as Wi-Fi, Bluetooth, ZigBee and WiMax networks.

[0032] The radio communication resources 106 can include portions of authorized radio frequency bands, portions of unlicensed radio frequency bands, or portions of a mixture of authorized and unlicensed radio frequency bands. The radio communication resources 106 available for carrying wireless communication signals between the base station 102 and the user equipment 104 can be further divided into a physical downlink channel 110 for sending wireless signals from the base station 102 to the user equipment 104 and a physical uplink channel 120 for sending wireless signals from the user equipment 104 to the base station 102. The physical downlink channel 110 can also include a physical downlink control channel (PDCCH) 112 and a physical downlink shared channel (PDSCH) 114. Similarly, the physical uplink channel 120 can also include a physical uplink control channel (PUCCH) 122 and a physical uplink shared channel (PUSCH) 124. For simplicity, other types of downlink and uplink channels are not shown in Figure 1shown in, but within the scope of the present disclosure. Control channels PDCCH 112 and PUCCH 122 can be used to carry control information in the form of, for example, downlink control information (DCI) messages 116 and uplink control information (UCI) messages 126. For example, in addition to carrying other control information (such as power control commands), DCI message 116 can be used to allocate PDSCH communication resources to user equipment 104. For example, UCI message 126 can be used to carry acknowledgment feedback information regarding communication resource allocation sent from base station 102 to user equipment 104 via DCI message 116. Shared channels PDSCH 114 and PUSCH 124 can be allocated and used to transmit downlink data messages 118 and uplink data messages 128 between base station 102 and user equipment 104.

[0033] Communication resources 106 can include both radio frequency resources and time slots. In some embodiments, the entire accessible bandwidth of radio frequency resources can be divided into multiple radio frequency bandwidth parts (BWPs). Each BWP can include multiple radio frequency physical resource blocks (PRBs). In the context of orthogonal frequency division multiplexing (OFDM) technology, each frequency PRB can also include a predetermined number of OFDM subcarriers with a predetermined subcarrier frequency spacing. For example, each frequency PRB can include 12 OFDM subcarriers. Multiple configurable values can be provided for the subcarrier frequency spacing, and the UE can select these values based on its signal processing capabilities. For example, the subcarrier frequency spacing can be configured to 15 KHz, 30 KHz, 60 KHz, 120 KHz, or 240 KHz. The OFDM signal can be modulated onto one or more radio frequency carriers.

[0034] The time slot dimension of communication resources 106 can be organized into frames and subframes with a predetermined duration. In a specific embodiment, the duration of a frame can be predefined as 10 ms. A frame can be divided into a predetermined number of subframes. For example, a 10 ms frame can be divided into 10 subframes, where each subframe lasts 1 ms. Each subframe can be further divided into multiple time slots. In the context of OFDM, each time slot can be used to transmit a predetermined number of OFDM symbols in a sequence (e.g., 14 OFDM symbols). Related to the configurable OFDM subcarrier spacing described above, the number of time slots in a subframe is configurable. For example, a subframe can include 1, 2, 4, 8, or 16 time slots corresponding to subcarrier spacing configurations of 15 KHz, 30 KHz, 60 KHz, 120 KHz, and 240 KHz, respectively.

[0035] In some embodiments, communication resource 106, which includes radio frequency resources and time slots, forms a two-dimensional communication resource grid (having a frequency dimension and a time dimension). This resource grid can be partitioned into the various uplink and downlink channels discussed above with reference to Figure 1 Allocation within each channel can be further performed. For example, PDSCH resources can be allocated for sending data from the base station to the UE, and each allocation can include one or more PRBs in frequency and one or more time slots in time.

[0036] The DCI message 116 can be used by the base station 102 to notify the UE 104 of the allocation of PRBs in the PDSCH 112, as well as other information (such as power control commands) that can be included in the DCI message. Although the DCI message 116 includes PDSCH allocation information, it can also include information for controlling the HARQ process. In one embodiment of HARQ regarding the transmission of the DCI message 116, the DCI message 116 can be sent to the UE 104 in a specific time slot together with the PDSCH allocation information and HARQ information, which includes, for example, an acknowledgement feedback timing indicator (AFTI) and a redundancy version (RV) for forward error correction. After receiving the DCI message 116, the UE will decode the DCI message, perform error detection, and, if an error is detected, perform error correction according to the RV. If the received DCI message is error-free or can be error-corrected, the UE 104 will choose to either send an acknowledgement immediately if available or send an acknowledgement to the base station according to the timing specified by the AFTI included in the received DCI message. If an error is detected and the error cannot be corrected, the UE 104 will choose to send a negative acknowledgement to prompt the base station 102 to automatically retransmit the entire DCI message once a retransmission request is available according to the timing specified by the AFTI, or send partial information that can be used to help correct the error in the previously received DCI message. The acknowledgement and negative acknowledgement from the UE 104 can be included, for example, as part of the UCI message 126. In the case where the base station 102 does not receive any response from the UE within a predefined time window (e.g., no acknowledgement when the DCI message is lost or the UCI message carrying the acknowledgement / negative acknowledgement is lost), the base station 102 will then retransmit the DCI message. The base station only proceeds to the next new DCI message until an acknowledgement for the previously sent or retransmitted DCI message is received. The term "negative acknowledgement" used in this disclosure refers to sending a negative acknowledgement to indicate that a message has not been received or has been received in error, while the term "no acknowledgement" used in this disclosure indicates that the base station has not received any acknowledgement or negative acknowledgement message.

[0037] The above embodiments basically adopt the stop-and-wait method regarding the HARQ process for transmitting and acknowledging DCI messages. In other words, no new DCI message is sent from the base station until an acknowledgment of the previously sent DCI message is received from the UE. For applications in unlicensed radio frequency bands, there may be significant differences in the processing capabilities of different UEs. Some UEs may not be able to perform the decoding, error detection, and error correction of correctly received DCI messages in a timely manner during the predetermined typical time window specified in the DCI message. Since an acknowledgment may not be provided in a timely manner in these cases, even if the previous DCI message is received error-free or can be error-corrected but only delayed, the base station 102 will retransmit the DCI message. In this case, wasted retransmissions occur.

[0038] In some exemplary embodiments of the present disclosure, as described in further detail below, a single PDSCH can be allocated in one or more PDSCH groups. Each DCI message for PDSCH allocation can be used to allocate one or more PDSCHs of the same PDSCH group. The PDSCH group can span multiple DCI allocations. The acknowledgment or non-acknowledgment feedback response made by the UE 104 can be triggered by the base station 102 and sent by the UE 104 based on the PDSCH group rather than for each DCI. The transmission of the acknowledgment or non-acknowledgment of one or more PDSCH groups by the UE 104 via the UCI message (including the PDSCH allocation in the current DCI message and the previous unacknowledged PDSCH allocation in the previous DCI message) can be commanded and triggered by a special indicator included in the current DCI message. A single UCI message can provide acknowledgment and non-acknowledgment responses for a single PDSCH group or multiple PDSCH groups. When all the current and outstanding PDSCHs in the group are acknowledged, the PDSCH allocation group is considered successful. The maximum number of coexisting PDSCH groups not yet acknowledged, denoted by M, can be predefined. For example, M can be 2, 4, 8, or any other integer value.

[0039] As will be shown in various specific embodiments below, grouping the PDSCH allocations provides improved HARQ efficiency and reduces unnecessary retransmissions of DCI messages. The various information fields within the DCI can be designed accordingly to facilitate HARQ based on PDSCH groups. Figure 2 An example DCI message 200 showing some of the DCI fields is shown. Specifically, Figure 2Shows relevant fields of DCI message 200, which can be designed to facilitate group-based HARQ. For example, DCI message 200 may include HARQ field 202. This HARQ field 202 may include but is not limited to the current PDSCH allocation group identifier (G) 206, acknowledgment feedback trigger indicator 208, current PDSCH group acknowledgment indicator 210, acknowledgment feedback timing indicator (K1) 212, and other HARQ control information 214 (such as RV for forward error correction and other HARQ-related information). As Figure 2 shown, the DCI message may also include a PDSCH allocation field 204, which indicates the PDSCH allocations 220 and 224 carried by this particular DCI message. In the above two-dimensional communication resource grid, each of the PDSCH allocations in 204 may include one or more PDSCHs in frequency and one or more time slots in time. Multiple PDSCH allocations in 204 may be within the same BWP, or may come from multiple BWPs. The PDSCH allocations in 204 may be associated with one or more radio frequency carriers.

[0040] Figure 2 Each of the DCI messages 200 in can be used to allocate multiple PDSCHs of one of the M PDSCH groups. Each of the M PDSCH groups may be uniquely identified by a group ID. The current PDSCH allocation group ID field 206 in DCI message 200 indicates the group ID of the PDSCH allocation included in this current DCI message. In Figure 2 the example, in the current DCI message 200, two PDSCHs 220 and 224 of the PDSCH group with group ID G are allocated among a maximum number of M PDSCH groups.

[0041] The acknowledgement feedback trigger indicator 208 (alternatively referred to as the trigger indicator 208) and the acknowledgement feedback timing indicator (K1) 212 (alternatively referred to as the timing indicator 212) are used in cooperation as the aforementioned special indicator, which is used to command and trigger the UE to send group-based acknowledgements via UCI messages. For example, the acknowledgement feedback trigger indicator 208 specifies a subset of M PDSCH groups with current and / or previously unacknowledged PDSCH allocations, and the UE is triggered to send a UCI message including group-based acknowledgements or non-acknowledgements at the time slot specified by the acknowledgement timing indicator (K1) 212. For example, the acknowledgement feedback trigger indicator 208 can be implemented as a bitmap. Specifically, it can contain M equal bits that have a one-to-one correspondence with the M PDSCH groups. A value of "1" specified for a particular bit in the trigger indicator bitmap can indicate that the corresponding PDSCH group is triggered to provide an acknowledgement or non-acknowledgement feedback according to the timing specified in the timing indicator 212. A value of "0" specified for a particular bit in the trigger indicator bitmap can indicate that the corresponding PDSCH group is not triggered and may choose not to provide an acknowledgement or non-acknowledgement feedback at the time slot specified in the timing indicator 212. The bitmap implementation for the trigger indicator 208 allows for the simultaneous triggering of acknowledgements for multiple PDSCH groups. The PDSCH groups with a value of 1 in the bitmap are referred to as being involved or triggered. As an alternative method to the trigger indicator bitmap, the trigger indicator 208 can take the form of a PDSCH group index. However, this may alternatively be more suitable for referring to a trigger group to trigger a single PDSCH group in each DCI message.

[0042] The timing indicator 212 can be specified as one of a set of predefined time values. The time values can be measured in terms of the number of time slots. Alternatively, the timing indicator 212 can be specified by one of a set of predefined time indices into a predefined lookup table for the corresponding time values measured in terms of the number of time slots. The number of time slots indicates the time position after the triggering of the DCI message, which commands the UE to feedback acknowledgement or non-acknowledgement information via a UCI message.

[0043] In some embodiments, the UCI message including the acknowledgment or non-acknowledgment of the PDSCH group involved in the trigger indicator 208 may still not need to trigger by specifying the acknowledgment timing indicator K1 212 using a special value (e.g., a non-numerical value indicated as "X"). This provides the main mechanism that allows the UE to select to delay the transmission of the UCI message that contains the acknowledgment or non-acknowledgment of the PDSCH allocation of the PDSCH group involved in the trigger indicator 208. Thus, when the timing indicator K1 field 212 of the DCI message is specified as "X", the UE can choose not to send the acknowledgment or non-acknowledgment at any default time after the transmission of the DCI message, and the base station is also allowed to continue to send new DCI messages even without receiving the acknowledgment of the previous DCI message.

[0044] In some embodiments, to prevent excessive delay in the acknowledgment or non-acknowledgment feedback, the use of the non-numerical value "X" for the acknowledgment timing indicator K1 212 may be restricted. For example, for a PDSCH allocation group (indicated by the group ID 206) between the time slot when the DCI message allocating the first batch of PDSCHs of the group is sent and the time slot when the entire group is acknowledged by the UE, the non-numerical value "X" can be used at most a predetermined number of times (e.g., once, twice, or other predetermined number of times). Once this limit is reached, for this group between these two times, a numerical time value or time index may need to be specified for the timing indicator 212 of the DCI allocating the PDSCH. Once the group of PDSCHs is acknowledged, this group starts over, and the next DCI message allocating additional PDSCHs for this group may again include the timing indicator specified as "X".

[0045] In some embodiments, there may be multiple coexisting groups with outstanding and unacknowledged PDSCH allocations. The next DCI message allocating an additional PDSCH to any one of the groups (as indicated by the group ID field 206) may specify the acknowledgment feedback timing indicator 212 as a numerical value. Regardless of the group ID field 206 in the DCI message, such a DCI message can trigger the acknowledgment of all PDSCH groups involved by the acknowledgment feedback trigger indicator 208.

[0046] Continue Figure 2, the group confirmation indicator field 210 of the DCI message 200 can be used as a flag or a toggle field to indicate whether the PDSCH group specified by the group ID field 206 has any outstanding PDSCH allocations awaiting confirmation. For example, the base station 102 can use a bitmap with M bits to keep track of whether all outstanding PDSCH allocations have been confirmed for each of the M PDSCH groups, with each bit corresponding to one of the M PDSCH groups. When an acknowledgment for all current and previous unacknowledged PDSCH allocations for a PDSCH group is received, the base station flips or toggles the corresponding bit in the bitmap, and the corresponding bit will be used as the group confirmation indicator field 210 in the next DCI message with the corresponding group ID 208. Thus, the group confirmation indicator field (or bit) 210 keeps track of the cycle of the outstanding and confirmed status of the PDSCH group through bit flipping or toggling. As long as the group confirmation indicator bit 210 is not flipped, the size of the pool of unacknowledged PDSCH allocations for the corresponding group will increase as new PDSCHs are allocated to the group. The flipping of the indicator bit 210 will indicate that all outstanding PDSCHs for the group have been confirmed, and the group can start over.

[0047] Figure 3 illustrates an exemplary operation flow 300 of the base station 102 and the UE 104 according to Figure 2 the DCI design. In Figure 3 , various shapes (e.g., rectangles, circles, triangles, pentagons) represent messages or operations related to various PDSCH groups. The message passing performed by the base station 102 is shown in the Figure 3 upper half of Figure 3 , while the message passing and operations performed by the UE 104 are shown in the Figure 3 lower half of

[0048] Figure 3 . The flow 300 advances in time units to each time slot, as indicated by the arrow 301. The time slots are indicated by 302 to 311. For illustrative purposes only, the time slots 302 to 311 are shown in a consecutive order. Figure 3 Other time slots not shown in

[0048] Figure 3 can be located between the explicitly shown time slots. Messages for the base station with a dashed outline and a cross-hatched fill pattern (such as 320, 322, 324, 326, 330, 332, and 334) represent non-trigger DCI messages (e.g., DCI messages with a non-numeric "X" for the trigger indicator 208), while messages with a solid outline and no fill pattern (such as 328) represent trigger DCI messages (e.g., DCI messages with a numeric value for the trigger indicator 208).It is shown that base station 102 starts to serially transmit non-triggered DCI messages 320, 322, 324, 326 to allocate PDSCH for several different PDSCH groups in time slots 302, 303, 304, and 305 respectively. UE 104 receives DCI messages 320 and 324 without errors or with correctable errors. UE 104 also receives DCI message 322 with uncorrectable errors and does not receive DCI message 326 (e.g., the message is lost). Since these DCI messages are non-triggered, UE 104 can choose not to immediately send an acknowledgment or non-acknowledgment message to the base station. Alternatively, as shown at 340, 342, and 344, UE 104 can store acknowledgments and non-acknowledgments for later transmission.

[0049] The base station 102 then transmits a trigger DCI message 328 in time slot 306. As an example, the trigger DCI message 328 can include a PDSCH allocation belonging to the same PDSCH group as DCI 320 (rectangle). The trigger DCI message 328 can include a trigger indicator field 208 that specifies to feedback all outstanding and unacknowledged PDSCH allocations. The trigger DCI message 328 can also specify in its timing indicator field 212 that the UCI message for acknowledgment or non-acknowledgment feedback sent by UE 204 should appear in time slot 307, which is K1 time slots after time slot 306, as shown at 313. In response to the trigger DCI message 328, UE 104 first generates and stores an acknowledgment for the PDSCH allocation included in the DCI message 328 (shown as 346), and then collects the stored acknowledgments 340, 344, and 346 as 352 (including both 340 and 346 of the same PDSCH group) and 356, and collects the non-acknowledgment 342 as 354 to form a UCI message 350, and sends the UCI message 350 to the base station 102, as shown by arrow 351.

[0050] Continue Figure 3, upon receiving the UCI message 350, the base station 102 detects that the PDSCH groups associated with the DCI messages 320 / 328 (the same group) and DCI message 324 (another group) have been successfully received, and continues to flip or switch the acknowledgment status bits of these PDSCH groups, as shown in 353. The base station 102 also determines that the PDSCH group associated with DCI 322 has been incorrectly received by the UE, and that the PDSCH group associated with the DCI message 326 has not been acknowledged, and thus does not flip or switch the corresponding acknowledgment status bits of these groups. The base station 102 thus continues with the retransmission of the unacknowledged PDSCHs associated with the DCI messages 322 and 326. The retransmissions shown as 330 and 332 occur in time slots 308 and 309 respectively. These retransmissions may be correctly received by the UE104. The UE 104 may then store the acknowledgments for the PDSCH allocations included in these two DCIs, as shown in 360 and 362.

[0051] The base station 102 continues to send a new DCI message 334 at time slot 310, where the PDSCH allocation belongs to the same PDSCH group as the previously transmitted DCI message 324. In the DCI message 334, the group acknowledgment indicator 210 for this group (indicated by the group ID field 208) will be designated as having been flipped / switched. As a result, upon receiving the DCI message 334, the UE will determine that the base station now understands that the UE has received all the previous PDSCH allocations in this group (triangle), and will remove all the previously stored acknowledgments for this group, as shown in 380. The UE will further store the acknowledgment (or non-acknowledgment) for the PDSCH allocation included in the new DCI message 334 for the next trigger message, as shown in 370.

[0052] In some embodiments, a default trigger time may be specified to provide an alternative option for the UE to respond with an acknowledgment UCI message after receiving and processing the DCI message. For example, the default value may be 2 time slots, 4 time slots, 7 time slots, or other default durations. After receiving and processing (decoding, error detection, and error correction) the DCI message, the UE may respond to the received DCI message by selecting one of multiple options based on the value specified in the trigger time indicator K1 field 212 of the DCI message and these default trigger times.

[0053] For example, when the timing indicator K1 field in the DCI is specified as "X" (a non-numerical value), as one of multiple options, the UE can choose to store and save the acknowledgments or non-acknowledgments for the received PDSCH allocations in the order of reception until the next special DCI message that contains commands for immediate acknowledgments and non-acknowledgments for unacknowledged PDSCH allocations. For example, the Radio Network Temporary Identifier (RNTI) technique can be used to specify a special DCI message for the UE to identify it as a special DCI message containing feedback commands. In this option, (1) in addition to responding to such commands, the UE can also choose to ignore all default times, or send UCI messages filled with non-acknowledgments at the default times before the time slot requested by the special DCI feedback command for the UE to respond. In a second alternative option, the UE can store and save the acknowledgments and non-acknowledgments until the numerical time slot specified by the timing indicator K1 field. Similarly, in this option, the UE can choose to ignore all default times, or send UCI messages at these default times by filling them with non-acknowledgments at the default times before the time slot specified by the timing indicator K1 field.

[0054] As another example, when the timing indicator K1 field in the DCI message is specified with a numerical value, as one of multiple options, the UE can choose to store and save the acknowledgments or non-acknowledgments for the PDSCH allocation in the current DCI message, and send a UCI message containing the stored acknowledgments and non-acknowledgments for the current PDSCH allocation and the previously stored acknowledgments at the time slot specified by the timing indicator K1 field in the current DCI message. In this option, the UE can choose to ignore all default times, or send UCI messages at these default times by filling them with non-acknowledgments at the default times before the time slot specified by the timing indicator K1 field.

[0055] In yet another alternative, when the DCI message is being decoded, error detected, and error corrected by the UE, the UE can still choose to send acknowledgments or non-acknowledgments without saving them until the next special DCI message with a feedback command or the next DCI with a numerical timing indicator K1 field, or simply submit non-acknowledgments at the default time slot.

[0056] Accordingly, the above-described embodiments provide a DCI field and a configurable operation mechanism for the base station 102 and the UE 104 to efficiently and timely utilize HARQ for sending and receiving PDSCH allocations and acknowledgments. Compared to a simple wait-and-stop method without grouping, the above-described embodiments provide the UE with multiple opportunities to send acknowledgments and non-acknowledgments for a specific PDSCH group before the corresponding PDSCH allocation DCI message is determined to require retransmission by the base station. A mechanism for delaying the transmission of acknowledgments or non-acknowledgments is provided for UEs that are slower in processing DCI (especially in unlicensed radio frequency bands) without causing unnecessary retransmission of DCI by the base station. These embodiments also include a mechanism for limiting such delays to avoid excessive extension of the feedback acknowledgments or non-acknowledgments.

[0057] The above-described embodiments assume that the DCI message includes a PDSCH allocation. In some other embodiments, the DCI message for triggering group acknowledgment or non-acknowledgment feedback may be sent by the base station 102 without including any PDSCH allocation. For example, such a DCI message may specify an empty group ID 206, which indicates that no PDSCH allocation is included in this DCI message, and further specify a trigger indicator 208 and a timing indicator 212 for controlling the acknowledgment and non-acknowledgment feedback. In other words, a DCI message not intended for PDSCH allocation can also be designed to include some of the HARQ fields that are used to trigger the acknowledgment or non-acknowledgment feedback for unacknowledged PDSCH allocations. This mechanism can be used as an alternative to a special DCI message with a feedback command that is implemented using ANTI as discussed above.

[0058] Although these embodiments can particularly improve the HARQ process for applications in unlicensed frequency bands, the basic principles described herein apply to any radio frequency band and any type of messaging process in any type of wireless access network. Additionally, although the embodiments specifically relate to HARQ, the basic principles also apply to general ARQ, in which a forward error correction process is not used and a message needs to be retransmitted in the case of non-acknowledgment or failure to receive an acknowledgment.

[0059] In addition, the embodiments described herein can be used in conjunction with multi-process or multi-thread HARQ or ARQ schemes. In particular, multiple independent messaging processes or threads can be implemented. For each of the processes or threads, a stop-and-wait HARQ or ARQ method can be used. However, the multiple processes or threads can execute independently and can be interleaved such that a message in one process or thread can be sent while another process or thread waits for an acknowledgment or retransmission. The following embodiments focus on single-process or single-thread messaging, but can be extended by one of ordinary skill in the art without creative effort to multi-process or multi-thread schemes, where the HARQ or ARQ process in each independent process or thread is based on PDSCH groups rather than on individual DCIs.

[0060] Figures 4 to 7 More specific exemplary embodiments that follow the basic principles discussed above are shown. In all of these examples, it is assumed that there are two potentially coexisting PDSCH groups (e.g., M = 2, where group G = 1 and group G = 2). It is also assumed that during the acknowledgment period, the maximum number of times the timing indicator ( Figure 2 of 212) is designated as non-numeric ("X") for one PDSCH group is 1. When these parameters are modified, the Figures 4 to 7 embodiments can be modified accordingly.

[0061] In Figure 4 , the DCI message for PDSCH allocation is sent by base station 102 at time slots 402, 404, and 408. As shown by group ID fields 410, 430, and 460, Figure 4All DCI messages in are sent for PDSCH allocation for one of two PDSCH groups (group G = 1). Each acknowledgment feedback trigger indicator bitmap is specified as "10", which indicates that only acknowledgment or non-acknowledgment feedback for PDSCH allocation for PDSCH group G = 1 is required to trigger. Two PDSCHs 420 and 422 are allocated at time slot 402, while three PDSCHs 440, 442, and 444 are allocated at time slot 404, and another two PDSCHs 470 and 472 are allocated at time slot 450. The timing indicator field for the DCI message at time slot 402 is specified as "X", and thus as an option the UE can choose not to send any acknowledgment UCI. The timing indicator field for the DCI message at time slot 404 can no longer be specified as "X". For example, it can be specified as K1 = 2, as shown at 436. This potentially triggers the UE to send an acknowledgment UCI message at time slot 406 (which is K1 time slots after time slot 404). The acknowledgment in the UCI message can include a bitmap of PDSCH allocations for group G = 1 so far. In this example, 5 PDSCHs have been allocated, and if all of them are successfully received by the UE, the acknowledgment bitmap will contain 5 positive bits, as shown at 450. Once the base station receives the acknowledgment feedback, it flips / switches the group G = 1 acknowledgment indicator field from "0" in 414 and 434 to "1" in 464. The UE accordingly discards all acknowledgments previously stored for group G = 1. The allocation of PDSCH for group G = 1 restarts at time slot 408, and the timing indicator field 466 can again be specified as the non-numeric "X".

[0062] In Figure 5In it, the DCI message for PDSCH allocation is sent by the base station 102 at time slots 502, 504, and 508. As indicated by the group ID field 510, the DCI message is sent for PDSCH group G = 1 at 502; while as indicated by the group ID fields 530 and 560, the DCI message is sent for PDSCH group G = 2 at 504 and 508. The acknowledgment feedback trigger indicator bitmap is designated as "10" at time slots 502 and 504 (as shown in 512 and 532), which indicates that only the acknowledgment or non-acknowledgment feedback for triggering the PDSCH allocation of group G = 1 is required to trigger. The acknowledgment feedback trigger indicator bitmap is designated as "01" at time slot 508, which indicates that only the acknowledgment or non-acknowledgment for triggering the PDSCH allocation of group G = 2 is required to trigger. Two group-1 PDSCHs 520 and 522 are allocated at time slot 502, while three group-2 PDSCHs 540, 542, and 544 are allocated at time slot 504, and two additional group-2 PDSCHs 570 and 572 are allocated at time slot 508. The timing indicator field for the DCI message at time slot 502 is designated as the non-numeric "X", and thus the UE can choose not to send any acknowledgment UCI message. For group G = 2, the timing indicator field for the DCI message at time slot 504 can be designated as "X" (since "X" has not been designated for group-2 yet). In this specific example, the timing indicator field of the DCI message at time slot 504 is designated as K1 = 2 (instead of "X"), as shown in 536. This will trigger the UE to send an acknowledgment UCI message at time slot 506, which is K1 = 2 time slots after time slot 504. The acknowledgment can include the bitmap for the PDSCH allocations for group G = 1 so far (since the acknowledgment feedback trigger indicator 532 is designated as 10, thus only requesting the acknowledgment feedback for group-1). Accordingly, the acknowledgment bitmap will contain 2-bit positive acknowledgments (if the transmission is successful), as shown in 550. Once the base station receives the 2-bit acknowledgment, it flips / switches the group G = 1 acknowledgment indicator from "0" in 514 to "1" (such that the group acknowledgment indicator field in the DCI message for allocating the group-1 PDSCH will be set to "1"). The UE accordingly discards all the acknowledgments previously stored for group G = 1. The DCI message at time slot 508 allocates the PDSCH with the timing indicator K1 field having a value of 4 for group-2 again, as shown in 566. The trigger indicator field is further designated as "01" for requesting group-2 feedback (as shown in 562). Thus, the UE sends the requested feedback at time slot 509, which is 4 time slots after time slot 508. The UCI sent will contain a 5-bit acknowledgment bitmap corresponding to the five PDSCH allocations for group-2 at time slots 504 and 508 (none of which have been previously acknowledged).Accordingly, the UE will remove all the acknowledgment information stored for Group-2, and the PDSCH for Group-2 will restart.

[0063] In Figure 6 , the DCI message for PDSCH allocation is sent by the base station 102 at time slots 602, 604, and 608. As indicated by the group ID fields 610 and 660, at time slots 602 and 608, the DCI message is sent for PDSCH group G = 1; while as indicated by the group ID field 630, at time slot 604, the DCI message is sent for PDSCH group G = 2. The acknowledgment feedback trigger indicator bitmap is designated as "10" at time slots 602 and 608 (as shown by 612 and 662), which indicates that only the acknowledgment or non-acknowledgment feedback for triggering the PDSCH allocation of group G = 1 is required to trigger. The acknowledgment feedback trigger indicator bitmap is designated as "11" at time slot 604, as shown by 632, which indicates that both group-1 and group-2 feedbacks are required to trigger. Two group-1 PDSCHs 620 and 622 are allocated at time slot 602, while three group-2 PDSCHs 640, 642, and 644 are allocated at time slot 604, and another three group-1 PDSCHs 670, 672, and 674 are allocated at time slot 608. The timing indicator field for the DCI message at time slot 602 is designated as the non-numeric "X", as shown by 616, and thus the UE can choose not to send any acknowledgment UCI message. For group G = 2, the timing indicator field for the DCI message at time slot 604 can be designated as "X" (since "X" has not been designated for Group-2 yet). In this particular example, the timing indicator field for the DCI message at time slot 604 is alternatively designated as K1 = 2, as shown by 636. This will trigger the UE to send an acknowledgment UCI message at time slot 606 (which is K1 = 2 time slots after time slot 604). The acknowledgment can include the bitmap for the PDSCH allocations for both group-1 and group-2 so far (since the acknowledgment feedback trigger indicator 632 is designated as 11, thus requesting acknowledgment feedback for both groups). Accordingly, the acknowledgment bitmap will contain 5-bit positive acknowledgments (if the transmission is successful), as shown by 650. Once the base station receives the 5-bit acknowledgment, it will flip / toggle the acknowledgment indicator from "0" to "1" for both groups (such that the group acknowledgment indicator field in the DCI message for allocating the PDSCH in any one of the groups will be set to "1"). The UE accordingly discards all the acknowledgments previously stored for both groups. The PDSCH allocations for both groups will restart.

[0064] In Figure 7In [the figure], the DCI message for PDSCH allocation is sent by the base station 102 at time slots 702, 706, and 708. As indicated by group ID fields 710 and 730, at time slots 702 and 706, the DCI message is sent for PDSCH group G = 1; while as indicated by group ID field 760, at time slot 708, the DCI message is sent for PDSCH group G = 2. The acknowledgment feedback trigger indicator bitmap is designated as "10" at time slots 702 and 706 (as shown by 712 and 732), which indicates that only the acknowledgment or non-acknowledgment feedback for triggering the PDSCH allocation for group G = 1 is required to be triggered. The acknowledgment feedback trigger indicator bitmap is designated as "11" at time slot 708, which indicates that both group-1 and group-2 feedbacks are required to be triggered. Two group-1 PDSCHs 720 and 722 are allocated at time slot 702, three group-1 PDSCHs 740, 742, and 744 are allocated at time slot 706, and another three group-2 PDSCHs 770, 772, and 774 are allocated at time slot 708. The timing indicator field for the DCI message at time slot 702 is designated as the non-numeric "X", and thus the UE can choose not to send any acknowledgment UCI message. However, in this example, the UE chooses the option to send an acknowledgment immediately after it processes the DCI message sent at time slot 702. The UCI message containing a 2-bit acknowledgment can thus be received by the base station at time slot 704, as shown by 750. Therefore, the UE does not need to store the acknowledgments for PDSCHs 720 and 722. The group acknowledgment indicator bit for group 1 can also be flipped / switched from "0" in 714 to "1" in 734. Therefore, after time slot 704, the allocation of the PDSCH for group-1 can start again. Thus, for group-1, the timing indicator field for the DCI message at time slot 706 can be designated as the non-numeric "X" again, as shown by 736. Therefore, at time slot 706, the UE can choose to store and save the acknowledgments for the PDSCH allocation for group-1. The DCI message at time slot 708 allocates three PDSCHs for group-2, where the trigger indicator field is designated as "11" (as shown by 762, requesting acknowledgments for both groups) and the timing indicator field has K1 = 3, as shown by 766. Therefore, the UE sends the UCI message at time slot 709, which is K1 = 3 time slots after time slot 708. The UCI message will contain a 6-bit acknowledgment bitmap corresponding to the PDSCH allocations 740, 742, and 744 for group-1 and 770, 772, and 774 for group-2, as shown by 780.

[0065] Turning to another aspect of maintaining track of the number of outstanding (or unacknowledged) PDSCH allocations via multiple DCI messages in HARQ. In one embodiment, one or more additional fields in the DCI can be used to track the allocated PDSCH. These fields can be designed as indices to track each of the outstanding unacknowledged PDSCHs (including both those allocated in the current DCI message and those allocated in previously allocated and unacknowledged DCI messages), as well as the total count of outstanding unacknowledged PDSCHs. Thus, the Current Downlink Assignment index (C-DAI) can be used to track each PDSCH allocation, and the Total Downlink Assignment Index (T-DAI) can be used to track the total outstanding PDSCH allocations. In the context of the multiple sets of PDSCH allocations discussed above, each PDSCH group can independently track using a separate set of C-DAIs. Two exemplary methods in a multi-set environment can be utilized to implement the T-DAI.

[0066] In the first method, an independent T-DAI accumulates within each PDSCH group, and this accumulation may not be allowed to cross PDSCH groups. In this method, the current DCI message can include T-DAI fields, each for one of all the PDSCH groups involved by the trigger indicator bitmap field 208 discussed above, to separately track the total count of outstanding PDSCHs in each PDSCH group. The current DCI message can also include a set of C-DAIs, each set of C-DAIs corresponding to one of the currently allocated PDSCHs as an index. These indices can start and continue from the previously outstanding PDSCHs of the current group (as specified by the group ID field 206 of Figure 2 ), such that all the outstanding PDSCHs of each PDSCH group are separately indexed for tracking purposes. In the second method, a single T-DAI accumulates across PDSCH groups to track the total count of outstanding PDSCHs of all PDSCH groups. In this method, the C-DAI fields can be processed in a manner similar to the first method, but only a single T-DAI field may need to be included in the current DCI message.

[0067] As shown by Figures 8 to 10 The example further illustrates the determination of the C-DAI and T-DAI fields. Figure 8 Similar to Figure 4 part, and shows the C-DAI and T-DAI determination in the case of a single PDSCH group. As Figure 8 shown, the DCI message at time slot 402 includes two PDSCH allocations for group-1. AsFigure 8 As shown in 802, each of the PDSCH allocations is tracked by (C-DAI, T-DAI), and these two PDSCH allocations are indexed using C-DAI of 1 and 2, where T-DAI is 2 (for 2 group-1 pending allocations). The DCI message at slot 404 also allocates three group-1 PDSCHs. As shown in 804, these three PDSCH allocations continue to be indexed with C-DAI of 3, 4, and 5, and the T-DAI for group-1 cumulatively increases to 5.

[0068] Figure 9 Shows separately tracking two groups of PDSCH allocations. In particular, Figure 9 The example shown in is similar to the part of where the C-DAI and T-DAI fields are shown. More specifically, the DCI message at slot 602 allocates two group-1 PDSCHs, while the DCI message at slot 604 allocates three group-2 PDSCHs. Similar to Figure 6 , the DAI field 902 tracks the C-DAI and T-DAI for group-1, while the DAI field 904 tracks the C-DAI and T-DAI for group-2, except that the two PDSCH groups are tracked separately. Since the acknowledgment feedback trigger indicator 632 is specified as "11", the DCI message for slot 604 may also include the DAI for group-1, as shown in 906 (which is the same as 902), because no new group-1 allocation is made. Figure 8

[0069] Figure 10 Figure 10 Shows two groups of PDSCH allocations that track using a separate C-DAI for each PDSCH group, but accumulate one T-DAI for all PDSCH groups. Specifically, Figure 9 Similar to

[0070]

[0070]

[0070] Now turn to confirm the transmission of feedback UCI messages via the PUCCH, especially in the unlicensed radio frequency band. As discussed above, since access to the unlicensed radio frequency band can be based on schemes such as Listen-Before-Talk (LBT) and Clear Channel Assessment (CCA) procedures, for the purpose of accurate channel activation detection, according to regulatory policies, it can be mandatory for messages (including acknowledgment messages in the ARQ / HARQ process) to occupy a sufficiently large portion of a specific channel bandwidth unit or be spread over a sufficiently large portion of a specific channel bandwidth unit (e.g., in the unlicensed band near 5 GHz, for a 20 MHz channel bandwidth, at least 70% or 80%). UCI messages sent via the PUCCH in the unlicensed band may be subject to this mandatory requirement. UCI messages carrying HARQ acknowledgments or non-acknowledgments can typically be sent using a single physical resource block (PRB). However, this single PRB transmission will not meet the minimum frequency band occupancy percentage requirement. In some embodiments, a single PRB can be mapped to multiple PRBs spread across the bandwidth, thus meeting the frequency band occupancy mandatory requirement. For example, the bandwidth can be divided into interleaved PRBs. A single PRB can be mapped to a PRB interleaving that includes multiple PRBs spread across the bandwidth.

[0071] Various methods can be used to determine the transmission symbol sequence of PRB interleaving. In the first method, the transmission sequence corresponding to a single PRB implementation can be repeated in other PRBs in the PRB interleaving. This repetition can be implemented using several different options for reducing the Peak-to-Average Power Ratio (PAPR) and Cubic Metric (CM) of the PUCCH. As one of the options, the cyclic shift for the OFDM symbol can cycle in position between the interleaved PRBs. In other words, the base sequence transmitted by the PRB interleaving is the same. The difference between the transmitted sequences is the shift position of the cyclic shift. In one implementation, this difference in the cyclic shift position between the PRB in the PRB interleaving body and the initial position of the cyclic shift can be a predetermined value. In an alternative implementation, this difference in the cyclic shift position between the PRB and the initial position of the cyclic shift can be dynamically specified by a DCI message. For example, the DCI message for allocating PUCCH resources can provide these values when the DCI message is transmitted. In yet another implementation, this difference in the cyclic shift position between the PRB in the PRB interleaving body and the initial position of the cyclic shift can be determined by adding one or more parameters corresponding to the PRB index of the PRB interleaving to the algorithm for determining the cyclic shift position. As a second option, phase rotation on the PRB interleaving can be implemented. The phase rotation can be implemented based on each PRB or based on each resource element. The phase rotation can be implemented by multiplying a complex phase value in the time domain after the inverse Fourier transform in the OFDM modulation process. The determination of the phase rotation (or complex phase value) can be based on a selection made via an analog process. Alternatively, the phase rotation for each PRB in the PRB interleaving can be implemented by stepping through a phase sequence with equal intervals. For example, for a 15 KHz subcarrier spacing, each PRB in the PRB interleaving can be sequentially phase rotated by π / 5. As another example, for a 30 KHz subcarrier spacing, each PRB in the PRB interleaving can be sequentially phase rotated by 2π / 5. Extending from the above methods, the base station can configure different UEs to transmit at other PRB interleavings with different cyclic shift cycles or phase rotations in the same frequency band to achieve orthogonality between different UEs.

[0072] In a second method for determining a transmission sequence for PRB interleaving, the base sequences for each of the extended PRBs in the PRB interleaving can be different rather than the same. A sequence index m can be provided, and the base sequence for each PRB in the PRB interleaving can be derived based on the sequence index m. Several different implementations for specifying the sequence index m can be used. For example, higher-level control information can be used to specify multiple indices m (e.g., when the pucch-GroupHopping parameter in a 5G implementation is equal to "disabled"). For another example in a 5G implementation, when the pucch-GroupHopping parameter is equal to "enabled", the algorithm for determining the index m can be modified to include a parameter related to the index of the PRB.

[0073] In a third method for determining a transmission sequence for PRB interleaving, a single long symbol sequence can be mapped to multiple extended PRBs in the PRB interleaving. For example, the length of the long symbol sequence can be determined by the number of PRBs in the PRB interleaving. The long symbol sequence can be based on, for example, a Zadoff-Chu (ZC) sequence. Thus, a UCI message can be mapped to the long ZC sequence. The long ZC sequence can be further mapped to the PRBs in the PRB interleaving. In this method, the cyclic shift corresponding to the extended PUCCH allocated for transmitting the UCI message can be predetermined by the base station (e.g., by setting an initial cyclic shift index including {0, 2, 4, 6, 8, 10} in a 5G implementation). Therefore, the above implementation effectively extends a single PRB UCI message to multiple PRBs of the PRB interleaving, and these PRBs occupy a portion of the radio frequency bandwidth, and the occupancy percentage of this portion of the radio frequency bandwidth is equal to or greater than the occupancy percentage required for accessing an unlicensed radio frequency band.

[0074] Finally, in a 5G implementation, the transmission of data from the base station to the user equipment via the PDSCH allocation discussed above can rely on a type B mapping regarding the design of the demodulation reference signal (DMRS). In the context where the downlink spectrum is shared by LTE and 5G New Radio (NR), especially in an unlicensed radio frequency band, the DMRS positions for type B mapping can be designed such that they do not conflict with the cell-specific reference signal (CRS) of LTE.

[0075] When transmitting a signal in the PDSCH by using type B mapping, and when the time domain length of the transmission includes 2 to 14 symbols, the DMRS symbol positions can be determined in several alternative ways. In a first way, the DMRS symbol positions of the type A mapping of the PDSCH data transmission with the corresponding symbol length can be used for type B mapping. For example, for a PDSCH signal with a symbol length less than 7, only those located at the symbol positionsl 0 A DMRS symbol at. For PDSCH signals with symbol lengths of 8 and 9, the DMRS symbol positions can be set at symbol positions l 0 and 7. For PDSCH signals with symbol lengths of 10, 11, and 12, the DMRS symbol positions can be set at symbol positions l 0 , 6, and 9. For PDSCH signals with symbol lengths of 13 and 14, the DMRS symbol positions can be set at positions l 0 , 7, and 11.

[0076] In the second mode, the DMRS symbol positions of type B mapping with corresponding symbol lengths in the uplink PUSCH can be used for type B mapping for the downlink (PDSCH). An example is shown in Table 1 below, showing the DMRS symbol positions for PDSCH signals with various different symbol lengths. The leftmost column in Table 1 shows the PDSCH symbol length. The leading labels 0, 1, 2, and 3 each represent the number of DMRS symbols. For PDSCH symbol lengths less than 4, there is at most 1 DMRS symbol. For PDSCH symbol lengths between 5 and 7, there are at most 2 DMRS symbols. For PDSCH symbol lengths between 8 and 9, there are at most 3 DMRS symbols. For PDSCH symbol lengths between 10 and 14, there are at most 4 DMRS symbols.

[0077] Table 1

[0078]

[0079] In the third mode, the DMRS symbol positions for various PDSCH lengths between 2 and 14 can follow the DMRS positions previously defined for PDSCH symbol lengths 2, 4, and 7 in type B mapping. For example, when the PDSCH symbol length is less than 7, there is only one preposed DMRS symbol at l 0 , and there are no additional DMRS. When the number of symbols of the PDSCH is greater than 7, the symbol positions of the DMRS can be at symbols l 0 and 4, or l 0 , 4, and 7, where l 0 , 4, and 7 are the symbol positions relative to the starting symbol of the PDSCH.

[0080] This design solves the determination of the DMRS symbol position for PDSCH signals with different symbol lengths and will reduce the LTE and NR conflicts discussed above. For example, for a PDSCH signal with a symbol length of 10 starting from symbol position 3, the additional DMRS will conflict with the symbol position of the CRS of LTE. Therefore, the transmission of such a PDSCH signal may need to be shifted backward by one symbol. The shift can be predetermined. It can also be dynamically configured through a control message. For 10 symbols of the PDSCH sent from symbol 4, the preposed DMRS also conflicts with the symbol position of the CRS, and the symbol position of the DMRS may need to be l 0 and 5.

[0081] In addition, the determination of the processing time corresponding to the newly defined PDSCH symbol lengths (lengths other than 2, 4, and 7) of mapping type B can be based on the following. For example, the processing time of a newly added PDSCH signal with a symbol length of 3 can be the same as the processing time of a previously defined PDSCH signal with a symbol length of 2. For another example, the processing time of a PDSCH signal with a symbol length of 5 or 6 can be specified to be the same as the processing time of a previously defined PDSCH signal with a symbol length of 4 or 7. For another example, the processing time of a PDSCH signal with a symbol length greater than 7 can be specified to be the same as the processing time of a previously defined PDSCH signal with a symbol length of 7.

[0082] The above description and the drawings provide specific example embodiments and implementations. However, the described subject matter can be embodied in various different forms, and thus, the subject matter covered or claimed is intended to be construed as not limited to any example embodiment set forth herein. It is intended to provide a reasonably broad scope for the subject matter claimed or covered. Among them, for example, the subject matter can be embodied as a method, device, component, system, or non-transitory computer-readable medium for storing computer code. Therefore, the embodiments can take, for example, the form of hardware, software, firmware, storage media, or any combination thereof. For example, the above method embodiments can be implemented by a component, device, or system including a memory and a processor by executing computer code stored in the memory.

[0083] Throughout the specification and claims, terms may have subtle meanings suggested or implied in the context in addition to the explicitly stated meanings. Similarly, as used herein, the phrase "in one embodiment / implementation" does not necessarily refer to the same embodiment, and the phrase "in another embodiment / implementation" as used herein does not necessarily refer to a different embodiment. For example, the claimed subject matter is intended to include combinations of example embodiments, in whole or in part.

[0084] In general, terms may be understood, at least in part, from their usage in context. For example, terms such as "and," "or," or "and / or" as used herein may include a variety of meanings that may depend, at least in part, on the context in which they are used. Generally, "or" when used in connection with a list (such as A, B, or C) is intended to mean A, B, and C (used in an inclusive sense here), as well as A, B, or C (used in an exclusive sense here). Additionally, the term "one or more" as used herein (at least in part depending on the context) may be used to describe any feature, structure, or characteristic in a singular sense, or may be used to describe a combination of features, structures, or characteristics in a plural sense. Similarly, terms such as "a," "an," or "the" may be understood to convey a singular usage or to convey a plural usage, at least in part depending on the context. Further, the term "based on" may be understood to not necessarily be intended to convey an exclusive set of factors, and may alternatively allow for the presence of additional factors that are not necessarily explicitly described, which also depends, at least in part, on the context.

[0085] References throughout this specification to features, advantages, or similar language do not imply that all features and advantages that can be realized by the solution should or are included in any single embodiment of the solution. Rather, language referring to features and advantages is understood to mean that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the solution. Thus, discussions of features and advantages, and similar language, throughout the specification may, but do not necessarily, refer to the same embodiment.

[0086] In addition, in one or more embodiments, the features, advantages, and characteristics of the solution may be combined in any suitable manner. Given the description herein, those of ordinary skill in the relevant art will recognize that the solution may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized that may not be present in all embodiments of the solution.

Claims

1. A method for triggering feedback on communication resource allocation from a wireless device, performed by a wireless access node, the method comprising: Generating a downlink control message, the downlink control message comprising: A set of wireless downlink communication resource allocations; A plurality of allocation feedback control fields, the plurality of allocation feedback control fields comprising: A resource group ID field that identifies a current allocation group among a plurality of allocation groups for the set of wireless downlink communication resource allocations; A feedback trigger group indicator that specifies a set of trigger allocation groups among the plurality of allocation groups for which the wireless device is to be triggered to provide the feedback; and A feedback timing indicator that specifies timing control information for triggering feedback from the wireless device, wherein the timing control information in the feedback timing indicator of the downlink control message comprises a non-numerical value for indicating to the wireless device to delay providing the feedback or a numerical value for specifying a future time slot in which the wireless device is to provide the feedback, wherein the non-numerical value also indicates to the wireless device to delay providing the feedback until at least the next downlink control message having a numerical feedback timing indicator field, and wherein the number of times the feedback timing indicator of the next downlink control message having the resource group ID field as the current allocation group is non-numerical is limited to 1 before all outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group are acknowledged by the wireless device; Sending the downlink control message to the wireless device to control the wireless device to provide feedback on all outstanding and unacknowledged wireless downlink communication resource allocations belonging to the set of trigger allocation groups according to the feedback timing indicator.

2. The method according to claim 1, wherein Some of the outstanding and unacknowledged wireless downlink communication resource allocations are sent from the wireless access node to the wireless device via other downlink control messages.

3. The method according to claim 1, wherein, The set of trigger allocation groups includes the current allocation group identified by the group resource ID field of the downlink control message.

4. The method according to claim 1, wherein The set of trigger allocation groups includes two or more allocation groups among the plurality of allocation groups.

5. The method according to claim 1, wherein, The outstanding and unacknowledged wireless downlink communication resource allocations include at least one retransmitted wireless downlink communication resource allocation.

6. The method according to claim 1, wherein The plurality of allocation feedback control fields of the downlink control message further includes an allocation feedback status field for indicating whether there are outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group in addition to the set of wireless downlink communication resource allocations included in the downlink control message.

7. The method according to claim 6, wherein The allocation feedback status field is determined by a toggle bit maintained for the current allocation group.

8. The method according to claim 7, wherein, The toggle bit for the current allocation group is configured to toggle when an acknowledgement of all outstanding and unacknowledged allocations in the current allocation group is received.

9. The method according to claim 7, wherein The acknowledgement status of each of the plurality of allocation groups is tracked by a corresponding toggle bit.

10. The method according to claim 1 further includes maintaining a separate numbered index for the outstanding and unacknowledged wireless communication resource allocations for each of the plurality of allocation groups.

11. The method according to claim 10, wherein, The plurality of allocation feedback control fields of the downlink control message further includes the separate numbered index for the set of wireless downlink communication resource allocations included in the downlink control message.

12. The method according to claim 10 further includes maintaining a separate total cumulative count for the outstanding and unacknowledged wireless communication resource allocations for each of the plurality of allocation groups.

13. The method according to claim 12, wherein, The plurality of allocation feedback control fields of the downlink control message further includes the separate total cumulative count for the outstanding and unacknowledged wireless communication resource allocations in the current allocation group identified by the resource group ID field of the downlink control message.

14. The method according to claim 12, wherein The plurality of allocation feedback control fields of the downlink control message further includes the separate total cumulative count for the outstanding and unacknowledged wireless communication resource allocations for the allocation groups specified by the feedback trigger group indicator of the downlink control message.

15. The method according to claim 10, wherein, The plurality of allocation feedback control fields of the downlink control message further includes a single total cumulative count for the outstanding and unacknowledged wireless communication resource allocations accumulated among all the allocation groups specified by the feedback trigger group indicator of the downlink control message.

16. The method according to claim 1, wherein Feedback on all outstanding and unacknowledged allocations from the wireless device includes a feedback bitmap that includes a single bit for each of all the outstanding and unacknowledged allocations, the all outstanding and unacknowledged allocations serving as an acknowledgement or non-acknowledgement indication.

17. The method according to claim 16 further includes retransmitting a wireless downlink communication resource allocation having a non-acknowledgement indication in the feedback bitmap using another downlink control message.

18. A method performed by a wireless device for providing feedback on an allocation of wireless downlink communication resources sent from a wireless access node, the method including: Receiving a downlink control message from the wireless access node, the downlink control message including: A set of wireless downlink communication resource allocations; A plurality of allocation feedback control fields, the plurality of allocation feedback control fields including: A resource group ID field that identifies a current allocation group among a plurality of allocation groups for the set of wireless downlink communication resource allocations; A feedback trigger group indicator that specifies a set of trigger allocation groups among the plurality of allocation groups for which the wireless device will be triggered to provide the feedback; and A feedback timing indicator that specifies timing control information for triggering feedback from the wireless device, wherein the timing control information in the feedback timing indicator of the downlink control message includes a non-numerical value for indicating to the wireless device to delay providing the feedback or a numerical value for specifying a future time slot in which the wireless device will provide the feedback, wherein the non-numerical value also indicates to the wireless device to delay providing the feedback until at least the next downlink control message having a numerical feedback timing indicator field, and wherein the number of times the feedback timing indicator of the next downlink control message having the resource group ID field of the current allocation group is non-numerical is limited to 1 before all outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group are acknowledged by the wireless device; Provide feedback on all outstanding and unacknowledged wireless downlink communication resource allocations belonging to the set of trigger allocation groups according to the feedback timing indicator.

19. The method according to claim 18, further comprising: When it is determined that the feedback timing indicator of the downlink control message includes a non-numerical value indicating to the wireless device to delay the feedback: Generate a first feedback data item corresponding to all outstanding and unacknowledged wireless downlink communication resource allocations belonging to the set of trigger allocation groups; And Store the first feedback data item in a repository for maintaining outstanding allocation feedback.

20. The method according to claim 18, when it is determined that the feedback timing indicator of the downlink control message includes a numerical value specifying a future time slot, transmit all outstanding and unacknowledged wireless downlink communication resource allocations belonging to the set of trigger allocation groups in the future time slot.

21. The method according to claim 18, wherein The set of trigger allocation groups includes the current allocation group identified by the group resource ID field of the downlink control message.

22. The method according to claim 18, wherein, The set of trigger allocation groups includes two or more of the plurality of allocation groups.

23. The method according to claim 18, wherein The outstanding and unacknowledged wireless downlink communication resource allocations include at least one retransmission of wireless downlink communication resource allocations performed by the radio access node.

24. The method according to claim 18, wherein, The plurality of allocation feedback control fields of the downlink control message further include an allocation feedback status field for indicating whether there are outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group in addition to the set of wireless downlink communication resource allocations included in the downlink control message.

25. The method according to claim 24, wherein The allocation feedback status field is determined by a toggle bit maintained for the current allocation group.

26. The method according to claim 24, wherein The method further includes: when the allocation feedback status field of the downlink control message indicates that there are no outstanding and unacknowledged wireless downlink communication resource allocations in the current allocation group, remove the feedback data item stored in the repository associated with the current allocation group.

27. The method according to any one of claims 18 to 26, wherein Each of the wireless downlink communication resource allocations corresponds to one or more physical resource blocks in a wireless communication resource grid of physical resource blocks.

28. The method according to claim 27, wherein, The feedback is sent by the wireless device using an uplink control message.

29. The method according to claim 28, wherein, The uplink control message is sent using one or more physical resource blocks in the wireless communication resource grid.

30. The method according to claim 29, wherein, The uplink control message occupies the interleaving of physical resource blocks within a predetermined frequency band.

31. A radio access network node or a wireless device, comprising a processor and a memory, wherein the processor is configured to read computer code from the memory to implement the method according to any one of claims 1 to 30.

32. A computer program product, comprising a non-transitory computer-readable program medium having computer code stored thereon, which when executed by a processor, causes the processor to implement the method according to any one of claims 1 to 30.

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