Periodic resource feedback

Abstract

The present invention discloses a method for transmitting feedback related to downlink transmission on periodic resources. A dynamic delay can be defined as the period between transmission and feedback transmission. The delay can be specified by the downlink transmission. The feedback transmission can be delayed to a later available time slot, or a flexible time slot can be switched to the uplink for feedback transmission.

Description

Technical Field

[0001] The following disclosure relates to feedback transmission for downlink messages carried on periodic resources. Background Art

[0002] Wireless communication systems, such as third generation (3G) mobile phone standards and technologies are well known. Such 3G standards and technologies have been developed by the Third Generation Partnership Project (3GPP). Third generation wireless communications have generally been developed to support macrocellular mobile phone communications. Communication systems and networks have evolved towards broadband and mobile systems.

[0003] In a cellular wireless communication system, a user equipment (UE) accesses a radio access network (RAN) via a radio link. The radio access network includes a group of base stations that provide radio links to user equipment located in a cell covered by the base station and an interface to a core network (CN) that provides overall network control. It is understood that the radio access network and the core network each perform their own functions related to the entire network. For convenience, the term cellular network refers to the combined radio access network and core network, and it is understood that the term refers to the corresponding system for performing the disclosed functions.

[0004] The 3rd Generation Partnership Project has developed the so-called Long Term Evolution (LTE) system, the Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN), for mobile access networks, in which one or more macro cells are supported by base stations of eNodeB or eNB (evolved NodeB). Currently, the LTE system is further developing towards the so-called 5G or NR (New Radio) system, in which one or more cells are supported by base stations of Next Generation Node (gNB). NR is proposed to use the Orthogonal Frequency Division Multiplexing (OFDM) physical transmission format.

[0005] The NR protocol is designed to provide the option of operating in unlicensed radio bands (called NR-U). When operating in unlicensed radio bands, gNBs and UEs must compete with other devices for access to the physical medium / resources. For example, Wi-Fi, NR-U, and LAA (licensed spectrum assisted access) may use the same physical resources.

[0006] The trend in wireless communications is to provide services with lower latency and higher reliability. For example, NR is designed to support ultra-reliable and low-latency communications (URLLC), while massive machine type communications (mMTC) is designed to support low latency and high reliability for small packet sizes (typically 32 bytes). Currently, a user plane latency of 1ms has been proposed with a reliability of 99.99999%, and 10 -5 or 10 -6 The packet loss rate.

[0007] Massive machine type communication services are designed to support a large number of devices over a long lifecycle through energy-efficient communication channels, where data transmission to and from each device occurs sporadically and infrequently. For example, a cell may be expected to support tens of thousands of devices.

[0008] The base station can configure periodic downlink (DL) semi-persistent scheduling (SPS) resources. The downlink semi-persistent scheduling (DL SPS) period can be set as low as 0.5ms, which is equivalent to 1 time slot with an SCS (subcarrier spacing) of 30kHz, making it suitable for ultra-reliable and low-latency communication services. In downlink semi-persistent scheduling transmission, the base station configures different downlink semi-persistent scheduling configurations (which may be applicable to a single or a group of UEs) to the user equipment (UE) through the radio resource control (RRC), and then sends a downlink control information (DCI) message to activate the required downlink semi-persistent scheduling configuration. The UE is therefore aware of the potential physical downlink shared channel (PDSCH) location, allowing the base station to transmit on the physical downlink shared channel without the associated physical downlink control channel (PDCCH) control message scheduling a specific transmission. This type of transmission reduces the alignment time, transmission time and processing time of the physical downlink shared channel, as well as the blocking probability of the physical downlink shared channel.

[0009] For downlink semi-persistent scheduling transmission, the base station can configure at least some parameters using higher layer signaling (e.g., RRC, radio resource control). The base station then activates the downlink semi-persistent scheduling configuration using a downlink control message sent using a special identity called a single cell radio network temporary identifier (SC-RNTI). Similar to the dynamic transmission of the downlink, when the base station configures and activates the downlink semi-persistent scheduling resources through a downlink control message, the activation downlink control message contains a physical downlink shared channel to hybrid automatic repeat request feedback (PDSCH-to-HARQ-feedback) indicator K1, indicating the number of time slots from the end of the physical downlink shared channel to the start of feedback on the physical uplink control channel (PUCCH). This parameter indicating the timing of the physical downlink shared channel to the hybrid automatic repeat request feedback is then used throughout the active time of the relevant semi-persistent scheduling configuration. If the user equipment receives the physical downlink shared channel in time slot n, the user equipment will send the hybrid automatic repeat request feedback in time slot n+K1. However, in a time division duplex (TDD) configuration, if time slot n+K1 is a downlink time slot, the user equipment cannot send a physical uplink control channel carrying hybrid automatic repeat request feedback in this time slot, and the transmission of the physical uplink control channel is cancelled after Release 15.

[0010] The rate of downlink semi-persistent scheduling can be very high using a period as low as 0.5ms, but the K1 value is indicated only once when the downlink semi-persistent scheduling configuration is activated. This is different from dynamic downlink scheduling, where the scheduling downlink control information will indicate the feedback timing of the scheduled transmission. In 5G, the network has extremely high control over the switching of downlink / uplink configurations and supports dynamic switching using slot-based downlink control information, thereby increasing the probability of collision between hybrid automatic repeat request feedback transmission resources and slot formats in semi-static and dynamic time division duplex configurations. The situation is even more serious if downlink slots are frequently configured.

[0011] When downlink semi-persistent scheduling with short period (e.g., as low as 0.5 ms) is configured for ULR and LLDC services / applications, collisions associated with HARQ can degrade the Quality of Service (QoS) of the ULR and LLDC communications. Figure 2In the example, downlink semi-persistent scheduling resources (SPS) are configured for the user equipment with a periodicity P in a time division duplex configuration (TDD configuration). The value K1 indicated by the activation downlink control information is 3. A physical downlink shared channel (PDSCH) is sent to the user equipment in the first semi-persistent scheduling resource. Based on K1 being 3, it is expected that the hybrid automatic repeat request feedback will be Figure 2 The hybrid automatic repeat request feedback is transmitted in the fourth time slot of the semi-persistent scheduling physical downlink shared channel, which is 3 time slots after the first time slot containing the semi-persistent scheduling physical downlink shared channel. However, this time slot is a downlink time slot and cannot be used for uplink (UL) transmission of hybrid automatic repeat request feedback. After Release 15, this hybrid automatic repeat request feedback is discarded and transmission is not resumed in the next physical uplink control channel (PUCCH).

[0012] If you use the version 15 mechanism and Figure 2 As shown, if the hybrid automatic repeat request feedback is discarded due to downlink / uplink time slot collision, the reliability of the physical downlink shared channel will be reduced due to the lack of hybrid automatic repeat request feedback (so the base station may not perform retransmission), and the specified quality of service may not be achieved. The base station can automatically retransmit data without hybrid automatic repeat request feedback, but when the user equipment correctly decodes the first transport block (TB) and discards the hybrid automatic repeat request feedback due to time division duplex collision, poor spectrum utilization will be caused due to unnecessary retransmissions.

[0013] The following disclosure relates to various improvements to cellular wireless communication systems. Summary of the invention

[0014] The purpose of this summary is to introduce the main concepts in a simplified form, the details of which are described in the detailed description below. This summary is not intended to specifically identify key features or essential features of the claimed subject matter, nor is it intended to be used to determine the scope of the claimed subject matter.

[0015] The present invention provides a method for transmitting feedback from a user equipment to a base station in a cellular communication network for use with periodically occurring downlink transmission resources, the method comprising: sending a signal from the base station to at least one user equipment to activate a semi-persistent scheduling (SPS) downlink configuration configured for the at least one user equipment, the semi-persistent scheduling downlink configuration comprising a plurality of periodic occasions of semi-persistent scheduling downlink transmission resources, and sending an indication of a delay period at the occasion of the semi-persistent scheduling downlink transmission resources, after which feedback associated with the occasion should be sent by the user equipment to the base station.

[0016] At this time, the indication of the delay period may be multiplexed with the downlink data transmission.

[0017] The signal activating the semi-persistent scheduling downlink configuration may include an indication that the delay period is to be dynamically defined.

[0018] The signal activating the semi-persistent scheduling downlink configuration may include a default delay period.

[0019] If no downlink transmission is received at the user equipment at an occasion when the downlink transmission resources are semi-persistently scheduled, or if no delay period is specified at an occasion, a default delay period may be used.

[0020] The deferral period may only apply at the time the deferral period is received.

[0021] The delay period may be applied to a specified number of opportunities for semi-persistent scheduling of downlink transmission resources.

[0022] The method may further include sending feedback from the user equipment to the base station after a delay period.

[0023] An ACK-only hybrid automatic repeat request protocol may be used.

[0024] A non-acknowledgement (NACK) feedback may be sent only when a power estimate value of a demodulation reference signal (DMRS) for an opportunity is higher than a threshold.

[0025] The delay period may be indicated by an index into a predefined table of delay values.

[0026] The predefined table of delay values ​​may include an entry indicating utilization of a predefined delay period.

[0027] The base station may indicate to at least one user equipment that the flexible time slot is defined as an uplink time slot for transmitting feedback for at least one occasion of the semi-persistently scheduled downlink resource.

[0028] The present invention also provides a method for feedback transmission from a user equipment to a base station in a cellular communication network for use with periodically occurring downlink transmission resources, the method being performed at the user equipment and comprising: receiving a signal from a base station, activating a semi-continuously scheduled downlink configuration configured for the user equipment, the semi-continuously scheduled downlink configuration comprising a plurality of periodic occasions for semi-continuously scheduled downlink transmission resources, and receiving an indication of a delay period at an opportunity for the semi-continuously scheduled downlink transmission resources, after which feedback associated with the opportunity should be sent by the user equipment to the base station.

[0029] At this time, the indication of the delay period may be multiplexed with the downlink data transmission.

[0030] The signal activating the semi-persistent scheduling downlink configuration may include an indication that the delay period is to be dynamically defined.

[0031] The signal activating the semi-persistent scheduling downlink configuration may include a default delay period.

[0032] If no downlink transmission is received at the user equipment at an occasion when the downlink transmission resources are semi-persistently scheduled, or if no delay period is specified at an occasion, a default delay period may be used.

[0033] The deferral period may only apply at the time the deferral period is received.

[0034] The delay period may be applied to a specified number of opportunities for semi-persistent scheduling of downlink transmission resources.

[0035] The method may further include sending feedback from the user equipment to the base station after a delay period.

[0036] An ACK-only hybrid automatic repeat request protocol may be used.

[0037] NACK feedback may be sent only when the power estimate of the demodulation reference signal for an opportunity is higher than a threshold.

[0038] The delay period may be indicated by an index into a predefined table of delay values.

[0039] The predefined table of delay values ​​may include an entry indicating utilization of a predefined delay period.

[0040] The method may further include receiving an indication from a base station that a flexible time slot is defined as an uplink time slot for transmitting feedback for at least one opportunity of the semi-persistently scheduled downlink resource.

[0041] The present invention also provides a method for transmitting feedback from a user equipment to a base station in a cellular communication network for use with periodically occurring downlink transmission resources, the method comprising sending a signal from the base station to at least one user equipment, activating a semi-persistent scheduling downlink configuration configured for the at least one user equipment, the semi-persistent scheduling downlink configuration comprising a plurality of periodic opportunities for downlink transmission resources, and sending an indication of a delay period to at least one user equipment, after which feedback associated with each opportunity for the semi-persistent scheduling downlink resources should be sent, and if the indicated delay period coincides with a downlink time slot, the user equipment sends feedback in a subsequently available uplink time slot.

[0042] The flexible time slot after the delay period is indicated for use as an uplink time slot for feedback transmission.

[0043] The time slot used for feedback transmission may be indicated in a slot format indication (SFI).

[0044] The present invention also provides a method for transmitting feedback from a user equipment to a base station in a cellular communication network for use with periodically occurring downlink transmission resources, the method comprising being performed at the user equipment and including: receiving a signal from the base station, activating a semi-persistent scheduling downlink configuration configured for the user equipment, the semi-persistent scheduling downlink configuration comprising a plurality of periodic occasions for semi-persistently scheduling downlink transmission resources, and receiving an indication of a delay period after which feedback associated with each occasion for the semi-persistently scheduling downlink resources should be sent, and if the indicated delay period occurs simultaneously with a downlink time slot, sending the feedback in a subsequently available uplink time slot.

[0045] The method may also include receiving an indication that a flexible time slot after the delay period is used as an uplink time slot for feedback transmission.

[0046] The time slot used for feedback transmission is indicated in the Slot Format Indication (SFI).

[0047] The present invention provides a feedback transmission method for use with a periodically occurring downlink transmission resource. At least one transmission in an opportunity of the downlink transmission resource includes an indication of a delay period after which feedback for the opportunity should be sent. The delay period may be indicated by a value multiplexed with the downlink transmission. When the periodic resource is activated, an indication that the delay period will be dynamically defined may be included. A default delay period may be specified.

[0048] If the dynamic delay period is activated, the user equipment is configured to decode the delay period from each transmission received on the relevant periodic resource and send feedback in the appropriate time slot based on the delay. ACK-only feedback may be used.

[0049] The base station may indicate to the user equipment that the flexible time slot is defined as an uplink time slot for feedback periodic resources. The user equipment may then utilize this time slot for feedback transmission. The user equipment may utilize this time slot to transmit feedback that is delayed due to a conflict with the downlink time slot of the originally indicated transmission time (e.g., if dynamic delay configuration is not used).

[0050] The base station may be configured to activate the periodic resources with an indication that defines a feedback delay value in each opportunity. The base station includes such delay value in each transmission on the relevant periodic resources.

[0051] The present invention also includes a user equipment and / or a base station, which is configured to perform the relevant steps of the method described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Further details, aspects and embodiments of the present invention will be described by way of example only with reference to the accompanying drawings. The elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For ease of understanding, the same reference numerals have been included in the various drawings.

[0053] Figure 1 A schematic diagram showing selected elements of a cellular communication system;

[0054] Figure 2 shows a feedback process with a fixed delay;

[0055] Figure 3 shows a feedback process with variable delay;

[0056] Figure 4 A feedback process showing feedback multiplexing; and

[0057] Figure 5 The feedback process using flexible time slots is shown. DETAILED DESCRIPTION

[0058] Those skilled in the art will recognize and appreciate that the details of the described examples are merely illustrative of some embodiments and that the teachings set forth herein are applicable to a variety of alternative arrangements.

[0059] Figure 1 A schematic diagram showing three base stations (e.g., eNBs or gNBs, depending on the specific cellular standard and terminology) that make up a cellular network. Typically, each base station will be deployed by a cellular network operator to provide geographic coverage for user equipment (UE) in that area. The base stations form the Radio Access Network (RAN). Each base station provides wireless coverage to user equipment in its area or cell. The base stations are interconnected via an X2 interface and connected to the core network via an S1 interface. It will be appreciated that only basic details are shown in order to illustrate the key features of a cellular network. A PC5 interface is provided between user equipment for SideLink (SL) communications. With Figure 1 The related interface and component names are used as examples only, and different systems operating on the same principles may use different nomenclature.

[0060] Each base station includes hardware and software that implements radio access network functions, including communication with the core network and other base stations, transmission of control and data signals between the core network and user equipment, and maintaining wireless communications with user equipment associated with each base station. The core network includes hardware and software that implements network functions, such as overall network management and control, and routing of calls and data.

[0061] The following disclosure provides a transmission mechanism for hybrid automatic repeat request (HARQ) feedback for downlink semi-persistent scheduling transmission (DL SPS) used in time division duplex (TDD) mode, thereby seeking to solve the problems discussed above. As described below, the transmission of HARQ feedback and the retransmission (if necessary) of the physical downlink shared channel (PDSCH) used for downlink semi-persistent scheduling transmission are guaranteed, while unnecessary retransmissions of the physical downlink shared channel are also avoided. Another object is to avoid increasing the overhead in the activation downlink control information (DCI) of the semi-persistent scheduling configuration and to provide flexibility for HARQ feedback transmission. In addition, an objective is to reduce waiting time, improve resource utilization, and reduce the overhead of the physical uplink control channel (PUCCH) when flexible time slots can be used for delayed HARQ feedback transmission.

[0062] As described above, the PDSCH-to-HARQ-feedback timing indicator is sent to the user equipment (UE) in the activation downlink control information for the downlink semi-persistent scheduling configuration sent by the base station. The bits in the PDSCH-to-HARQ-feedback timing indicator specify an index in a table specified in the radio resource control (RRC) parameter: dl-DatatoUL-ACK in the physical uplink control channel configuration (PUCCH-Config). Based on the index from the activation downlink control information, the user equipment knows that the index corresponds to the K1 value in the table. In downlink control information format 1_0, the 3 bits in the PDSCH-to-HARQ-feedback timing indicator are mapped to K1 values ​​from 1 to 8. In downlink control information format 1_1, there are 0 to 3 bits used to indicate the row index of K1 in the mapping table. The number of bits is determined by log2(I), where I is the number of elements (rows in the table) in (Physical Uplink Control Channel Configuration. Downlink-Data to Uplink-ACK) PUCCH-Config.dl-Datato UL-ACK.

[0063] Once the downlink semi-persistent scheduling resources are activated by the base station, the K1 value remains fixed throughout the semi-persistent scheduling (SPS) activation time. The user equipment always sends feedback K1 timeslots after the downlink semi-persistent scheduling physical downlink shared channel until the downlink semi-persistent scheduling resources are released by the base station. The downlink semi-persistent scheduling physical downlink shared channel (DLSPS PDSCH) is transmitted without an associated physical downlink control channel, so the base station cannot change K1 when the physical downlink shared channel is transmitted. When the downlink semi-persistent scheduling resource period is reduced to 1 timeslot of the semi-persistent scheduling of 30kHz, uplink / downlink timeslot conflicts may increase, so feedback cannot be transmitted in the timeslot indicated by K1. Another disadvantage of the period reduction is related to the high overhead of feedback. In Release 15, the user equipment will send non-acknowledgement (NACK) feedback in all occasions (occasions) where it does not decode a valid transport block, even if no transport block is transmitted in these resources (the base station may not use every opportunity of the periodic resources to transmit to the user equipment).

[0064] In order to overcome these shortcomings in the downlink semi-persistent scheduling feedback mechanism, the present disclosure proposes to dynamically indicate the semi-persistent scheduling physical downlink shared channel to feedback (SPS-PDSCH-to-feedback) timing with each semi-persistent scheduling transmission. That is, the K1 value can be dynamically indicated in each semi-persistent scheduling transmission, and the value is only applicable to a specific timing of periodic resources (or a set of usage of periodic resources). The activation downlink control information (DCI) may include a default value, which may then be overwritten by a specific value later. Alternatively, no value or a specific indication may be specified because the K1 value will be set based on each timing. For example, Table 1 shows an example table containing a set of possible K1 values, as well as a "no value" row. If the base station wishes to set a common value, the timing indicator value is set to correspond to one of rows 0-6 (000-110), and the user equipment will then interpret the K1 value accordingly and apply the value to the relevant downlink semi-persistent scheduling resources. If the base station wishes to send a specific K1 value for each opportunity, the activation downlink control information (activationDCI) will contain a value of 111 in its field corresponding to the non-numeric K1 value FFFF, which the user equipment interprets as an instruction that it waits for a specific K1 value for each opportunity. The example of Table 1 is given for explanation purposes only, and it is understood that any desired set of rows, K1 values, and mappings may be used as desired.

[0065]

[0066] Therefore, when the base station wishes to dynamically set K1 for each semi-persistent scheduling opportunity, it can include an indication in the DCI message that activates the semi-persistent scheduling resources to indicate that the K1 value will be set on a per-opportunity basis. For example, the table specified in dl-DatatoUL-ACK can contain an entry with a non-numeric value for K1 corresponding to the specific transmission value included in the activation DCI in the above example.

[0067] For downlink semi-persistent scheduling transmissions, there is no control transmission (downlink control information) on the PDCCH before each opportunity, so the K1 value for a specific opportunity can be included in the physical downlink shared channel transmission itself. For example, a set of bits (e.g., 0-3) in a specified position in the physical downlink shared channel can indicate K1. These bits are mapped to the K1 value in a table maintained by the user equipment, which can be the same table used when indicating K1 in the DCI message. Therefore, the semi-persistent scheduling physical downlink shared channel to feedback timing (SPS-PDSCH-to-feedback-timing) indication (K1) is sent together with the data on the physical downlink shared channel. This transmission can use similar techniques to the transmission of uplink control information over PUSCH. The semi-persistent scheduling physical downlink shared channel to feedback timing indication can be punctured on known resource elements in the physical downlink shared channel transmission. After puncturing an equivalent number of bits in the data of the physical downlink shared channel, the indication bits are added to the physical downlink shared channel (PDSCH). This method does not change the length of the codewords in the physical downlink shared channel, so it does not confuse the code rate or modulation and coding scheme (MCS) between the base station and the user equipment. However, the reliability of the physical downlink shared channel will be reduced due to the additional data carried.

[0068] In summary, some bits (eg, 0-3) of the data carried on the physical downlink shared channel are punctured and replaced by bits to indicate the K1 value for a specific downlink semi-persistent scheduling opportunity.

[0069] In the above example, K1 applies only to one occasion of downlink semi-persistent scheduling resources, but the value may persist to subsequent occasions. For example, the user equipment may continue to apply the specified value until a different value is received. This avoids the need to transmit K1 in each physical downlink shared channel, and instead may only transmit a value when the value changes.

[0070] Figure 3An example of the above process is shown. After configuring the downlink (DL) semi-persistent scheduling resources, a downlink control information (DCI) message 300 is sent to activate those resources. The DCI message 300 includes an indication that the K1 value for each opportunity will be set, for example by including a value mapped to a non-numeric K1 value in a table held by the user equipment. The semi-persistent scheduling resource (SPS resource) 301 is not used for transmission to the user equipment, but the semi-persistent scheduling resource (SPS resource) 302 is used. When transmitting on the resource 302, an indication of the K1 value to be used is carried on the physical downlink shared channel (PDSCH), for example by puncturing the data. In this example, the value transmitted corresponds to a K1 of 2, so the hybrid automatic repeat request feedback message 303 is transmitted after 2 time slots, which is the next available uplink time slot. When selecting a K1 value for a particular resource, the base station can select the next available uplink (UL) time slot based on the time division duplex configuration (TDD configuration) to minimize the delay of the feedback.

[0071] If the semi-persistent scheduling resource opportunity (SPS resource) 304 is utilized and the base station selects the next available uplink time slot, the feedback will also be transmitted at opportunity 303, so the feedback transmission needs to be multiplexed. Although such multiplexing is possible, if too many feedback messages are multiplexed, the transmission may become unreliable. Figure 4 An example is shown where four semi-persistent scheduling opportunities occur before the next uplink timeslot. For SPS PDSCH 1 and SPS PDSCH 2, K1 is set to values ​​of 4 and 3, respectively, so that feedback for both cases is transmitted in PUCCH 1. Instead of selecting the next uplink timeslot for feedback on SPS PDSCH 3 and SPS PDSCH 4, K1 is set to 3 and 2, respectively, so that feedback is transmitted in PUCCH 2. The number of feedback messages in each uplink timeslot is therefore limited to 2 to mitigate degradation. The base station may select the number of feedback messages to be multiplexed into the timeslot based on any appropriate parameters, such as the size of the PUCCH resources and the payload of the feedback. Other parameters, such as channel quality, may also be used. The base station may therefore select the K1 value based on the feedback transmission parameters to balance latency and reliability.

[0072] The timeslots may be defined as flexible to allow dynamic definition as uplink or downlink. The base station is aware of the flexible timeslots and may select such timeslots for HARQ feedback (which is defined as uplink) instead of waiting for the next statically defined uplink timeslot, thereby reducing latency.

[0073] Previously, the user equipment was required to send HARQ feedback for each downlink semi-persistent scheduling opportunity, even if a transport block (TB) was not transmitted at that particular opportunity. However, this resulted in high feedback overhead since negative feedback was transmitted when there was actually no transmission. Another disadvantage occurs when K1 is dynamically specified because the user equipment does not have a K1 value for the occasions when there was no transmission. To mitigate the second disadvantage, a default K1 value can be defined to allow feedback transmission when no physical downlink shared channel transmission is received. This default value can also be used if a specific K1 value cannot be determined from the physical downlink shared channel transmission. However, this does not reduce the feedback overhead.

[0074] To reduce feedback overhead, the user equipment may be configured to send feedback only when it is determined that the physical downlink shared channel transmission is for a user equipment in a specific downlink semi-persistent scheduling opportunity. If the TB is successfully decoded, an ACK is sent, and if the decoding fails, a non-ACK (NACK) is sent, but only under permitted conditions. For example, if the estimated demodulation reference signal (DMRS) power is higher than a threshold, a NACK may be sent because this is an indication that the message is sent to the user equipment. In an alternative approach, ACK-only feedback may be used, thereby not using a NACK message. That is, if the user equipment is able to decode the K1 value in the physical downlink shared channel and is able to decode the TB, the user equipment sends an ACK to the base station. In all other cases, no feedback transmission is sent. The base station knows at which times it has transmitted and the K1 values ​​set for those transmissions it did perform. Therefore, the base station knows when feedback should be received, and if feedback is not received at that time, it can be assumed that the transmission has failed and retransmitted. The ACK-only method is summarized in Table 2 below.

[0075]

[0076]

[0077] The ACK-only feedback configuration can be used only when K1 is dynamically indicated. Therefore, the activation of the dynamic K1 scheme can also be interpreted by the user equipment as an indication to activate ACK-only feedback.

[0078] In another approach, a set value may be defined for the physical downlink shared channel to hybrid automatic repeat request feedback timing (K1) as in the conventional approach, but if the resulting feedback time falls in a timeslot that is not an uplink timeslot, the feedback is delayed rather than discarded. The feedback may be delayed to the next uplink timeslot, or if the user equipment requires, the base station may indicate that certain flexible timeslots may be used as uplink timeslots for hybrid automatic repeat request feedback transmission. If flexible timeslots are indicated for hybrid automatic repeat request feedback transmission, only user equipment whose PUCCH configuration gives a valid PUCCH opportunity in that timeslot will use that timeslot for hybrid automatic repeat request feedback. The indication of available flexible timeslots may be sent as common or group common signaling, for example as part of a slot format indication (SFI). When the SFI is sent to the user equipment to update the flexible timeslots to uplink timeslots, it may include an indication of whether those timeslots may be used for hybrid automatic repeat request feedback.

[0079] This method does not require puncturing of bits in the physical downlink shared channel, so it does not affect the reliability of the physical downlink shared channel, but it may increase the delay due to the delay in feedback to the next available flexible time slot.

[0080] Figure 5 An example is shown where K1=2 causes hybrid automatic repeat request feedback transmissions for semi-persistent scheduling physical downlink shared channel (SPS PDSCH) 1 and semi-persistent scheduling physical downlink shared channel (SPS PDSCH) 2 to fall in a downlink timeslot. The user equipment buffers the feedback messages, and the base station sends downlink control information (SDI) containing the SFI to the user equipment, switching the next flexible timeslot to the uplink for hybrid automatic repeat request feedback. The SFI may include a flag indicating that the flexible timeslot is being switched to the uplink to carry a physical uplink control channel (PUCCH) (hybrid automatic repeat request feedback) transmission (rather than being used for PUSCH transmission). Therefore, the user equipment sends feedback for two semi-persistent scheduling opportunities in that timeslot. The flag indicating use for the physical uplink control channel (PUCCH) may trigger the user equipment to send all buffered hybrid automatic repeat request feedback messages.

[0081] right Figure 5A modified method, if the SFI indicates that the flexible time slot is switching to the uplink, but for PUSCH (not PUCCH), and the user equipment is scheduled to transmit data, the user equipment can multiplex the hybrid automatic repeat request feedback message in the uplink control information (UCI) with its scheduled PUSCH transmission. The user equipment can be configured to do this only when PUSCH reliability is not affected (for example, the hybrid automatic repeat request feedback size is below a threshold). As described above, an ACK-only feedback scheme can be used to reduce the number of feedback messages.

[0082] Code block group (CBG)-based feedback can improve downlink resource consumption, as it allows retransmission of only the failed code block group, rather than retransmitting the entire transport block. However, code block group feedback (CBG-feedback) will use more uplink resources. The user equipment can be configured to use code block group feedback if there are enough resources to transmit it without degrading other signals, otherwise use transport block-based feedback.

[0083] As discussed in the previous scheme, the feedback transmission at each semi-persistent scheduling opportunity will result in a lot of resource overhead, and the current scheme can also be better used as an ACK-only scheme. Therefore, when the user equipment successfully decodes the transport block, it sends an ACK at the specified time (or delays it to a suitable time slot in case of a conflict). Otherwise, the user equipment does not send anything.

[0084] It is understood that some or all of the various examples may be used in combination. For example, any process may use ACK-only feedback, or any process may adopt a default K1 value.

[0085] The specific aspects of the above disclosure are:

[0086] Dynamic indication of PDSCH to feedback timing K1 is dynamically indicated by some bits in the downlink semi-persistent scheduling physical downlink shared channel.

[0087] • Use a non-numeric K1 value in the activation downlink control information of the downlink semi-persistent scheduling configuration to inform the user equipment to use the dynamic K1 indication and ACK-only scheme.

[0088] K1 is dynamically indicated by some bits in the physical downlink shared channel of downlink semi-persistent scheduling.

[0089] · Combine the dynamic K1 indication scheme and the ACK-only scheme to ensure feedback transmission in uplink / downlink time slot conflicts in time division duplex configuration.

[0090] Delaying feedback in case of downlink / uplink collisions and allowing the use of flexible time slots for feedback with common indications.

[0091] · Use SFI as a trigger to send delayed HARQ feedback in dynamic TDD configuration.

[0092] If the UE has configured PUSCH in the flexible time slot, multiplexing of delayed HARQ feedback with PUSCH is enabled.

[0093] Although not shown in detail, any device or apparatus forming part of the network may include at least a processor, a storage unit and a communication interface, wherein the processor unit, the storage unit and the communication interface are configured to perform the method of any aspect of the invention. Further options and selections are described below.

[0094] Embodiments of the present invention, especially the signal processing functions of the next generation node (gNB) and the user equipment (UE), can be implemented using a computer system or architecture known to those skilled in the relevant art. The computer system used is, for example, a desktop, laptop or notebook computer, a handheld computing device (PDA, mobile phone, palmtop, etc.), a mainframe, a server, a client, or any other type of dedicated or general-purpose computing device that is desirable or suitable for a given application or environment. The computer system may include one or more processors, which may be implemented using a general or dedicated processing engine, such as a microprocessor, a microcontroller, or other control module.

[0095] The computer system may also include a main memory, such as a random access memory (RAM) or other dynamic memory, for storing information and instructions executed by the processor. Such a main memory may also be used to store temporary variables or other intermediate information during the execution of instructions by the processor. Similarly, the computer system may include a read-only memory (ROM) or other static storage device for storing static information and instructions of the processor.

[0096] The computer system may also include an information storage system, which may include, for example, a media drive and a removable storage interface. The media drive may include a drive or other mechanism to support fixed or removable storage media, such as a hard disk drive, a floppy disk drive, a tape drive, an optical disk drive, a compact disk (CD) or a digital video drive (DVD), a read or write drive (R or RW), or other removable or fixed media drives. The storage medium may include, for example, a hard disk, a floppy disk, a tape, an optical disk, a CD or a DVD, or other fixed or removable media that is read and written by a media drive. The storage medium may include a computer-readable storage medium having specific computer software or data stored therein.

[0097] In other embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computer system. Such components may include, for example, removable storage units and interfaces, such as program cartridges and cartridge interfaces, removable memory (e.g., flash memory or other removable memory modules) and memory slots, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage units to the computer system.

[0098] The computer system may also include a communication interface. Such a communication interface may allow software and data to be transmitted between the computer system and external devices. Examples of communication interfaces may include a modem, a network interface (e.g., an Ethernet or other NIC card), a communication port (e.g., a Universal Serial Bus (USB) port), a PCMCIA slot and card, etc. The software and data transmitted via the communication interface are in the form of signals, which may be electronic, electromagnetic, optical, or other signals that can be received by the communication interface medium.

[0099] As used herein, the terms "computer program product," "computer-readable medium," and the like may generally refer to tangible media, such as memory, storage devices, or storage units. These and other forms of computer-readable media may store one or more instructions and be provided to a processor, including a computer system, for use in order to cause the processor to perform specified operations. Such instructions 45, generally referred to as "computer program code" (which may be classified in the form of a computer program or other class), when executed, enable the computer system to perform the functions of an embodiment of the present invention. Note that the code may directly cause the processor to perform the specified operation, be compiled to perform this operation, and / or be combined with other software, hardware, and / or firmware elements (e.g., libraries for performing standard functions) to perform this operation.

[0100] The non-volatile computer readable medium may include at least one of the group consisting of a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory, and a flash memory. In embodiments where software is used to implement the elements, the software may be stored in a computer readable medium and loaded into a computer system using, for example, a removable storage drive. The control module (in this example, software instructions or executable computer program code) when executed by a processor in a computer system causes the processor to perform the functions of the present invention as described herein.

[0101] In addition, the inventive concept can be applied to any circuit that performs signal processing functions within a network element. It is expected that, for example, semiconductor manufacturers will adopt the inventive concept in the design of stand-alone devices, such as microcontrollers of digital signal processors (DSPs), or application specific integrated circuits (ASICs) and / or any other subsystem elements.

[0102] It should be understood that, for the sake of clarity, the above description describes embodiments of the present invention with reference to a single processing logic. However, the concept of the present invention can also be implemented by a plurality of different functional units and processors to provide signal processing functions. Therefore, references to specific functional units are only regarded as references to appropriate means for providing the described functions, rather than representing a strict logical or physical structure or organization.

[0103] Aspects of the present invention may be implemented in any suitable form, including hardware, software, firmware or any combination of these. The present invention may be optionally (at least partially) implemented as computer software running on one or more data processors and / or digital signal processors or configurable module components such as FPGA devices.

[0104] Therefore, the elements and components of the embodiments of the present invention can be implemented physically, functionally and logically in any suitable manner. In fact, the function can be implemented in a single unit, in multiple units or as a part of other functional units. Although the present invention has been described in conjunction with some embodiments, it is not intended to be limited to the specific form described herein. On the contrary, the scope of the present invention is limited only by the appended claims. In addition, although it seems that features have been described in conjunction with specific embodiments, it will be appreciated by those skilled in the art that the various features of the described embodiments can be combined according to the present invention. In the claims, the term "comprising" does not exclude the presence of other elements or steps.

[0105] Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by, for example, a single unit or processor. Furthermore, although individual features may be included in different claims, these features may be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and / or advantageous. Furthermore, the inclusion of a feature in one category of claims does not imply a limitation to that category of claims, but rather indicates that the feature is equally applicable to claims of other categories where appropriate.

[0106] Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. On the contrary, the steps may be performed in any suitable order. Furthermore, singular references do not exclude plural references. Thus, references to "a", "first", "second" etc. do not exclude plural references.

[0107] Although the present invention has been described in conjunction with some embodiments, it is not intended to be limited to the specific forms described herein. On the contrary, the scope of the present invention is limited only by the appended claims. In addition, although it seems that features have been described in conjunction with specific embodiments, it will be appreciated by those skilled in the art that the various features of the described embodiments can be combined according to the present invention. In the claims, the term "comprise" or "comprising" does not exclude the presence of other elements.

Claims

1. A method for transmitting feedback from a user equipment to a base station in a cellular communication network for use with periodically occurring downlink transmission resources, characterized in that The method is performed by a base station and comprises the following steps: sending a signal to at least one user equipment to activate a semi-persistent scheduling (SPS) downlink configuration configured for the at least one user equipment, the semi-persistent scheduling downlink configuration comprising a plurality of periodic opportunities for semi-persistent scheduling downlink transmission resources, and Sending an indication of a delay period at a time when semi-persistently scheduling downlink transmission resources, after which a hybrid automatic repeat request HARQ feedback associated with the time should be sent by the user equipment to the base station; wherein the base station indicates to the at least one user equipment that the flexible time slot is defined as an uplink time slot for transmitting hybrid automatic repeat request HARQ feedback for at least one opportunity of the semi-persistently scheduled downlink resource; The flexible time slot used for transmitting the hybrid automatic repeat request HARQ feedback is indicated as the uplink time slot in a slot format indication (SFI).

2. The method according to claim 1, characterized in that At the timing, the indication of the delay period is multiplexed with downlink data transmission, and the bits of the indication are added to the physical downlink shared channel PDSCH after puncturing the data of the physical downlink shared channel PDSCH by an equivalent number of bits as the indication.

3. The method according to claim 1, characterized in that The signal activating the semi-persistent scheduling downlink configuration includes an indication that a delay period is to be dynamically defined.

4. The method according to claim 1, characterized in that The signal activating the semi-persistent scheduling downlink configuration includes a default delay period.

5. The method according to claim 4, characterized in that If no downlink transmission is received at the user equipment at an occasion of the semi-persistently scheduled downlink transmission resource, or if no delay period is specified in an occasion, the default delay period is used.

6. The method according to claim 1, characterized in that The delay period applies only when the delay period is received.

7. The method according to claim 1, characterized in that The delay period is applied to a specified number of opportunities for semi-persistent scheduling of downlink transmission resources.

8. The method according to claim 1, characterized in that The method further includes sending hybrid automatic repeat request (HARQ) feedback from the user equipment to the base station after the delay period.

9. The method according to claim 1, characterized in that Use the ACK-only HARQ protocol.

10. The method according to claim 1, characterized in that A non-acknowledged (NACK) hybrid automatic repeat request (HARQ) feedback is sent only when the power estimation value of the demodulation reference signal for an opportunity is higher than a threshold.

11. The method according to claim 1, characterized in that The delay period is indicated by an index to a predefined table of delay values, the predefined table of delay values ​​including an entry indicating utilization of a predefined delay period.

12. The method according to claim 11, characterized in that The semi-persistent scheduling downlink configuration is in a downlink control information DCI message for activating semi-persistent scheduling resources, and the DCI message for activating semi-persistent scheduling resources includes an indication to indicate that the delay period K1 value will be set based on each opportunity, and the predefined table contains an entry having a non-numeric value of the delay period K1, corresponding to the above-mentioned specific delay period K1 value included in the transmission of the activation DCI.

13. The method according to claim 1, characterized in that The delay period is used to allow the user equipment to continue the application until a different delay period value is received.

14. A base station, characterized in that: include: Memory, which stores computer programs; A processor is configured to call and run the computer program stored in the memory, so that the base station equipped with the processor executes the method according to any one of claims 1 to 13.

15. A method for feedback transmission from a user equipment to a base station in a cellular communication network for use with periodically occurring downlink transmission resources, characterized in that: The method is performed at a user equipment and comprises the following steps: receiving a signal from a base station to activate a semi-persistent scheduling (SPS) downlink configuration configured for the user equipment, the semi-persistent scheduling downlink configuration comprising a plurality of periodic opportunities for semi-persistent scheduling downlink transmission resources, and receiving, at an occasion of semi-persistently scheduled downlink transmission resources, an indication of a delay period after which a hybrid automatic repeat request HARQ feedback associated with the occasion should be sent by the user equipment to the base station; wherein, receiving an indication from the base station that the flexible time slot is defined as an uplink time slot, the uplink time slot being used to transmit a hybrid automatic repeat request HARQ feedback for at least one opportunity of the semi-persistently scheduled downlink resource; The flexible time slot used for transmitting the hybrid automatic repeat request HARQ feedback is indicated as the uplink time slot in a slot format indication (SFI).

16. The method according to claim 15, characterized in that At the timing, the indication of the delay period is multiplexed with downlink data transmission, and the bits of the indication are added to the physical downlink shared channel PDSCH after puncturing the data of the physical downlink shared channel PDSCH by an equivalent number of bits as the indication.

17. The method according to claim 15, characterized in that The signal activating the semi-persistent scheduling downlink configuration includes an indication that a delay period is to be dynamically defined.

18. The method according to claim 15, characterized in that The signal activating the semi-persistent scheduling downlink configuration includes a default delay period.

19. The method according to claim 18, characterized in that If no downlink transmission is received at the user equipment at an occasion of the semi-persistently scheduled downlink transmission resource, or if no delay period is specified in an occasion, the default delay period is used.

20. The method according to claim 15, characterized in that The delay period applies only when the delay period is received.

21. The method according to claim 15, characterized in that The delay period is applied to a specified number of opportunities for semi-persistent scheduling of downlink transmission resources.

22. The method according to claim 15, characterized in that The method further includes sending hybrid automatic repeat request (HARQ) feedback from the user equipment to the base station after the delay period.

23. The method according to claim 15, characterized in that Use the ACK-only HARQ protocol.

24. The method according to claim 15, characterized in that Only when the power estimation value of the demodulation reference signal for a time opportunity is higher than the threshold, a non-acknowledged hybrid automatic repeat request (NACK) HARQ feedback is sent.

25. The method according to claim 15, characterized in that The delay period is indicated by an index to a predefined table of delay values, the predefined table of delay values ​​including an entry indicating utilization of a predefined delay period.

26. The method according to claim 25, characterized in that The semi-persistent scheduling downlink configuration is in a downlink control information DCI message for activating semi-persistent scheduling resources, and the DCI message for activating semi-persistent scheduling resources includes an indication to indicate that the delay period K1 value will be set based on each opportunity, and the predefined table contains an entry having a non-numeric value of the delay period K1, corresponding to the above-mentioned specific delay period K1 value included in the transmission of the activation DCI.

27. The method according to claim 15, characterized in that The delay period is used to allow the user equipment to continue the application until a different delay period value is received.

28. A user equipment, characterized in that: include: Memory, which stores computer programs; A processor is configured to call and run the computer program stored in the memory so that the user equipment equipped with the processor executes the method according to any one of claims 15 to 27.

29. A method for feedback transmission from a user equipment to a base station in a cellular communication network for use with periodically occurring downlink transmission resources, characterized in that: The method comprises the following steps: sending a signal from a base station to at least one user equipment to activate a semi-persistent scheduling (SPS) downlink configuration configured for the at least one user equipment, the semi-persistent scheduling downlink configuration comprising a plurality of periodic opportunities for downlink transmission resources, and sending, to at least one user equipment, an indication of a delay period after which a hybrid automatic repeat request (HARQ) feedback associated with each opportunity for semi-persistently scheduled downlink resources should be sent, and If the indicated delay period occurs simultaneously with a downlink time slot, the user equipment sends a hybrid automatic repeat request HARQ feedback in a subsequently available uplink time slot; wherein the base station indicates to the at least one user equipment that a flexible time slot is defined as the uplink time slot for transmitting hybrid automatic repeat request HARQ feedback for at least one opportunity of the semi-persistently scheduled downlink resource; The flexible time slot used for transmitting the hybrid automatic repeat request HARQ feedback is indicated as the uplink time slot in a slot format indication (SFI).

30. The method according to claim 29, characterized in that The flexible time slot after the delay period is indicated to be used as an uplink time slot for hybrid automatic repeat request HARQ feedback transmission.

31. The method according to claim 30, characterized in that The time slot used for hybrid automatic repeat request HARQ feedback transmission is indicated in the slot format indication (SFI).

32. A method for feedback transmission from a user equipment to a base station in a cellular communication network for use with periodically occurring downlink transmission resources, characterized in that: The method comprises executing at a user equipment and comprises the following steps: receiving a signal from a base station to activate a semi-persistent scheduling (SPS) downlink configuration configured for the user equipment, wherein the semi-persistent scheduling downlink configuration includes a plurality of periodic opportunities for downlink transmission resources, and receiving an indication of a delay period after which a hybrid automatic repeat request (HARQ) feedback associated with each opportunity for semi-persistently scheduled downlink resources should be sent, and If the indicated delay period occurs simultaneously with a downlink time slot, sending the feedback in a subsequently available uplink time slot; wherein, receiving an indication from the base station that the flexible time slot is defined as an uplink time slot, the uplink time slot being used to transmit a hybrid automatic repeat request HARQ feedback for at least one opportunity of the semi-persistently scheduled downlink resource; The flexible time slot used for transmitting the hybrid automatic repeat request HARQ feedback is indicated as the uplink time slot in a slot format indication (SFI).

33. The method according to claim 32, characterized in that Also included is receiving an indication that a flexible time slot after the delay period is used as an uplink time slot for hybrid automatic repeat request (HARQ) feedback transmission.

34. The method according to claim 33, characterized in that The time slot used for hybrid automatic repeat request HARQ feedback transmission is indicated in the slot format indication (SFI).

35. A user equipment, characterized in that: include: Memory, which stores computer programs; A processor is configured to call and run the computer program stored in the memory so that the user equipment installed with the processor executes the method as described in any one of claims 32 to 34.

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