DAI scheme for joint ACK / NACK feedback in multi-TRP / panel transmission

Abstract

According to some embodiments, an apparatus includes at least one processor and at least one memory, the at least one memory including computer program code. The at least one memory and the computer program code are configured to use at least one processor to cause the apparatus to configure multiple physical downlink control channels (PDCCHs) associated with multiple transmission reception points (TRPs), wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field, the DCI field including at least one downlink allocation index (DAI). The apparatus also sends at least one PDCCH associated with at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme.

Description

Technical Field

[0001] Certain embodiments may be related to communication systems. For example, some embodiments may be related to multiple transmission reception points (TRP) / panel transmissions. Background Art

[0002] Under the 3rd Generation Partnership Project (3GPP), Release 16 (Rel-16) work items (WI) include enhancements to Multiple-Input Multiple-Output (MIMO). Multiple TRP / panel transmissions are considered an important part of NR deployments because they facilitate enhanced mobile broadband (eMBB) operations, as well as the ability to improve the reliability of ultra-reliable low latency communications (URLLC) services. For example, the WI related to MIMO enhancements notes that enhancements to multiple TRP / panel transmissions include improved reliability and robustness over ideal and non-ideal backhaul. These enhancements may include specifying downlink control signaling enhancements for efficient support of non-coherent joint transmissions, and enhancements to uplink control signaling and / or (multiple) reference signals for non-coherent joint transmissions. Summary of the invention

[0003] According to some embodiments, a method may include configuring, by a user equipment, a plurality of physical downlink control channels (PDCCHs) associated with a plurality of transmission reception points (TRPs), wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field, the DCI field including at least one downlink allocation index (DAI). The method may also include transmitting, by a network entity, at least one PDCCH associated with at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme.

[0004] According to some embodiments, an apparatus may include means for configuring a plurality of physical downlink control channels (PDCCHs) associated with a plurality of transmission reception points (TRPs), wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field including at least one downlink allocation index (DAI). The apparatus may also include means for transmitting at least one PDCCH associated with at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme.

[0005] According to some embodiments, an apparatus may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code may be configured to use the at least one processor to cause the apparatus to at least configure multiple physical downlink control channels (PDCCHs) associated with multiple transmission reception points (TRPs), wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field, which includes at least one downlink allocation index (DAI). The at least one memory and the computer program code may also be configured to use the at least one processor to cause the apparatus to at least send at least one PDCCH associated with the at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme.

[0006] According to some embodiments, a non-transitory computer-readable medium may be encoded with instructions that, when executed in hardware, may perform a method. The method may configure multiple physical downlink control channels (PDCCHs) associated with multiple transmission reception points (TRPs), wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field that includes at least one downlink allocation index (DAI). The method may also send at least one PDCCH associated with at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme.

[0007] According to some embodiments, a computer program product may perform a method. The method may configure multiple physical downlink control channels (PDCCHs) associated with multiple transmission reception points (TRPs), wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field, which includes at least one downlink allocation index (DAI). The method may also send at least one PDCCH associated with at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme.

[0008] According to some embodiments, an apparatus may include circuitry configured to configure a plurality of physical downlink control channels (PDCCHs) associated with a plurality of transmission reception points (TRPs), wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field including at least one downlink allocation index (DAI). The circuitry may also transmit at least one PDCCH associated with at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme.

[0009] According to some embodiments, a method may include receiving, by a user equipment, at least one physical downlink control channel (PDCCH) associated with at least one dynamic allocation index (DAI) according to at least one local DAI counting scheme and / or at least one global DAI counting scheme, wherein the received PDCCH includes at least one downlink control information (DCI) field, the downlink control information (DCI) field including at least one downlink allocation index (DAI). The method may also include detecting, by the user equipment, at least one lost detected PDCCH. The method may also include determining, by the user equipment, at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size.

[0010] According to some embodiments, an apparatus may include means for determining at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size according to at least one local DAI counting scheme and / or at least one global DAI counting scheme, wherein a received PDCCH includes at least one downlink control information (DCI) field, the DCI field including at least one downlink allocation index (DAI). The apparatus may also include means for detecting at least one lost detected PDCCH. The apparatus may also include means for determining at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size.

[0011] According to some embodiments, an apparatus may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code may be configured to utilize the at least one processor to cause the apparatus to at least receive at least one physical downlink control channel (PDCCH) associated with at least one dynamic allocation index (DAI) according to at least one local DAI counting scheme and / or at least one global DAI counting scheme, wherein the received PDCCH includes at least one downlink control information (DCI) field, which includes at least one downlink allocation index (DAI). The at least one memory and the computer program code may also be configured to utilize the at least one processor to cause the apparatus to at least detect at least one lost detected PDCCH. The at least one memory and the computer program code may also be configured to utilize the at least one processor to cause the apparatus to at least determine at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size.

[0012] According to some embodiments, a non-transitory computer-readable medium may be encoded with instructions that, when executed in hardware, may perform a method. The method may receive at least one physical downlink control channel (PDCCH) associated with at least one dynamic allocation index (DAI) according to at least one local DAI counting scheme and / or at least one global DAI counting scheme, wherein the received PDCCH includes at least one downlink control information (DCI) field, including at least one downlink allocation index (DAI). The method may further detect at least one lost detected PDCCH. The method may further determine at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size.

[0013] According to some embodiments, a computer program product may perform a method. The method may receive at least one physical downlink control channel (PDCCH) associated with at least one dynamic allocation index (DAI) according to at least one local DAI counting scheme and / or at least one global DAI counting scheme, wherein the received PDCCH includes at least one downlink control information (DCI) field, including at least one downlink allocation index (DAI). The method may further detect at least one lost detected PDCCH. The method may further determine at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size.

[0014] According to some embodiments, an apparatus may include being configured to receive at least one physical downlink control channel (PDCCH) associated with at least one dynamic allocation index (DAI) according to at least one local DAI counting scheme and / or at least one global DAI counting scheme, wherein the received PDCCH includes at least one downlink control information (DCI) field, the DCI field including at least one downlink allocation index (DAI). The circuit may further detect at least one lost detected PDCCH. The circuit may further determine at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to properly understand the present disclosure, reference should be made to the accompanying drawings, in which:

[0016] Figure 1 An example of PDCCH scheduling the transmission of NR-PDSCH from various TRPs is shown.

[0017] Figure 2 An example of separate counts for multiple TRP transmissions is shown.

[0018] Figure 3 An example of no detection capability is shown where a bursty PDCCH is lost due to being blocked by a TRP.

[0019] Figure 4 An example of an optimization scheme based on local / joint counts and high-layer signaling for reference TRP according to some embodiments is shown.

[0020] Figure 5 Another example of an optimization scheme based on joint counting and high-layer signaling for counting order between TRPs according to some embodiments is shown.

[0021] Figure 6 A signaling diagram according to some embodiments is shown.

[0022] Figure 7 An example of a method performed by a network entity according to some embodiments is shown.

[0023] Figure 8 An example of a method performed by a user equipment according to some embodiments is shown.

[0024] Fig. 9 An example of a system according to some embodiments is shown. DETAILED DESCRIPTION

[0025] During the 3GPP Radio Access Network (RAN) Working Group (WG) 1, two techniques were agreed upon to support multi-TRP transmission in NR, specifically, single PDCCH design and multiple PDCCH design. A single PDCCH schedules one PDSCH, where separate layers are sent from separate TRPs, while multiple PDCCHs each schedule a corresponding PDSCH, where each NR-PDSCH is sent from a separate TRP. In the multiple PDCCH design, multiple PDCCHs from multiple TRPs can schedule corresponding multiple PDSCHs. The transmission of multiple PDCCHs can occur independently of the two TRPs. Therefore, this can be used for ideal and non-ideal backhaul.

[0026] 3GPP RAN1 Meeting 97 reached an agreement that joint HARQ-ACK feedback for multiple DCIs can be supported, and both Type 1 and Type 2 HARQ-ACK codebooks can be supported. Specifically, for separate ACK / NACK feedback for PDSCH received from different TRPs, if the index is configured and applied to all CCs, the UE should be able to generate a separate ACK / NACK codebook identified by the index. In addition, joint HARQ-ACK feedback can be supported for PDSCH received from different TRPs using multiple DCIs. When the PUCCH resources are at different PDCCH monitoring times, it is indicated by the PDSCH to HARQ Feedback Timing Indicator field for multiple DCIs for different TRPs, and both Type 1 and Type 2 HARQ-ACK codebooks are supported.

[0027] In addition, for multi-TRP operation based on multiple PDCCHs, one CORESET in "PDCCH-config" can correspond to one TRP. After 3GPP RAN1 96 and RAN1 97, in order to support multi-TRP / panel transmission based on multiple PDCCHs through intra-cell (i.e., the same cell ID), one CORESET in "PDCCH-config" corresponds to one TRP so as to link multiple PDCCH / PDSCH pairs with multiple TRPs.

[0028] In addition, for multi-TRP operation based on multi-PDCCH, the maximum number of CORESETs per "PDCCH-config" can be increased to 5. This TRP difference can be used for enhanced DAI indication to add ACK / NACK feedback when multiple TRP transmissions with multiple DCIs occur.

[0029] According to the Rel-15 DAI indication scheme, a dynamic codebook such as a type II codebook can reduce the codebook size relative to a semi-static codebook and can be an improvement on error-free downlink control signaling. However, in the event of loss detection of downlink control signaling, the NE and the UE may interpret the codebook size in different ways, and may further result in a feedback report of damage at least for the lost downlink control signaling. For example, the UE may be scheduled for downlink transmission in two subsequent PDCCH monitoring opportunities, but misses the first PDCCH, so the UE can only send confirmation for the PDSCH scheduled by the second PDCCH monitoring opportunity. In contrast, the NE may attempt to receive confirmation for two PDCCH monitoring opportunities and a mismatch occurs. In response to these errors, a downlink allocation index (DAI) may be used in the downlink DCI. The DAI field can be further divided into two parts, a counter DAI (cDAI) and an optional total DAI (tDAI) for carrier aggregation. The counter DAI included in the DCI can indicate the number of currently scheduled downlink transmissions, where the DCI is first sorted by carrier and then by time. The total DAI included in the DAI included in the DCI may indicate the total number of downlink transmissions across all carriers up to the current PDCCH monitoring occasion.

[0030] As defined in 3GPP Technical Specification (TS) 38.212Rel-15, for DCI format 1-0, the downlink allocation index may be 2 bits as defined in subclause 9.1.3 of TS 38.213. And for DCI format 1-1, if more than one serving cell is configured in DL and the higher layer parameter pdsch-HARQ-ACK-Codebook=dynamic, the number of bits of the downlink allocation index may be 4 bits, of which 2 MSB bits are counter DAI and 2 LSB bits are total DAI, and if only one serving cell is configured in DL and the higher layer parameter pdsch-HARQ-ACK-Codebook=dynamic, the number of bits is 2 bits, of which 2 bits are counter DAI.

[0031] For non-coherent joint transmission (NCJT), PDSCH can be sent from multiple TRPs via multiple PDCCH scheduling. For ideal backhaul or non-ideal backhaul with small latency, ACK / NACK bits can be returned jointly. The number of HARQ-ACK bits of the dynamic HARQ-ACK codebook can be determined based on the actual PDSCH from the carrier and the PDCCH loss. However, the 3GPP Rel-15 DAI indication scheme is not sufficient to correct for lost PDCCHs, where the PDCCHs may originate from multiple TRPs. Extension schemes can be added to 3GPP Rel-15 independently for each TRP, but not without some disadvantages. For example, such extension schemes will not be able to provide cross-checking capabilities between TRPs for lost PDCCHs. For example, as Figure 2 As shown, the cDAI information in the PDCCH from TRP2 will not be able to support the detection of the lost PDCCH from TRP1.

[0032] In addition, there is no capability to identify the last few lost PDCCHs. Due to the increased number of TRPs, the number of undetected lost PDCCHs will increase. Again, refer to Figure 2 , if the second PDCCH from TRP1 is missed by the UE, it can be detected because the UE can receive cDAI information based on the third PDCCH received from TRP1. However, the UE will not be able to detect the loss of the fourth PDCCH from TRP1 and the third or fourth PDCCH from TRP2 because they are the last PDCCH and there is no DAI information available for reference. For multiple TRP transmissions, the last PDCCH increases the number of PDCCH loss detections from the perspective of multiple TRPs.

[0033] However, a DAI indication scheme with a joint PDCCH count from multiple TRPs can be used to address the above shortcomings, as this includes a cross-check capability for detecting lost PDCCHs, and only one "last" DCI from a joint HARQ-ACK codebook perspective. DAI from a PDCCH with improved channel quality can also provide loss detection for PDCCHs with poor channel quality.

[0034] For multiple TRP transmissions, a situation in frequency range 2 (FR2) occurs where a PDCCH burst may be lost from one TRP due to blocking. Due to the granularity limitation caused by the 2-bit DAI indication, it is not possible to detect 4 consecutive lost PDCCHs. Figure 3As shown, the PDCCH scheduling 4 CCs from one TRP may be lost due to blocking, and according to the current Rel-15 DAI design, the UE is not aware of the existence of PDCCH transmission. Therefore, a special design using counting information from another TRP can be used to provide the detection capability of burst PDCCH loss.

[0035] Under the current 3GPP Rel-15 DAI scheme, 2 bits are used for the non-CA case and 4 bits are used for the CA case. For multiple TRP transmissions, there is no definition of how many bits are used for the non-CA case. PDCCH reliability can be enhanced by a smaller number of DAI bits, while the detection capability for lost PDCCHs can be enhanced by more DAI bits (such as 4 bits). For joint HARQ-ACK with multiple PDCCHs from multiple TRPs, the number of PDCCHs used to indicate the DAI count can be increased due to multiple TRPs. Therefore, an enhancement scheme is needed that balances the lost PDCCH detection capability with the DAI signaling overhead, which can exploit the channel quality differences between TRPs. Then, high-layer signaling can be used to switch between 2-bit and 4-bit DAI signaling schemes based on channel quality.

[0036] Certain embodiments described herein may provide a DAI enhancement scheme that achieves an improvement between signaling overhead and the ability to detect lost PDCCHs through 2-bit DAI for non-CA scenarios. In addition, the PDCCH loss detection capability may be improved for CA cases or through 4 bits for non-CA, through multiple DCI transmissions from multiple TRPs for joint ACK / NACK feedback DAI cases. Therefore, certain embodiments relate to improvements in computer-related technologies, specifically, enabling DAI indications to ensure the same understanding of the HARQ-ACK codebook size between network entities and user equipment. Certain embodiments may also save network resources and reduce power consumption of network entities and / or user equipment within the network by reducing redundant operations.

[0037] Figure 6 An example of a signaling diagram according to some embodiments is shown. The network entity (NE) 620 may be similar to Fig. 9 NE 910 in, and user equipment (UE) 630 can be similar to Fig. 9 Although only a single UE and a single NE are shown, the communication network may contain one or more of each of these entities.

[0038] In step 601, the NE 620 may determine whether at least one carrier aggregation is configured. For example, after determining that CA is not configured, the NE 620 may be configured to configure a number of bits 2 or 4 for the DAI, depending on, for example, channel quality. In various embodiments, the NE 620 may be configured to configure a 4-bit DAI for at least one cell edge user in response to at least one lost PDCCH detection capability of the NE 620 exceeding at least one performance threshold. Additionally or alternatively, the UE 630 may be configured to configure a 2-bit DAI for at least one cell center user in response to at least one probability of PDCCH loss being lower than at least one predetermined threshold.

[0039] In step 603, NE 620 may determine whether at least one DAI bit number is configured. For example, at least one DAI bit number may be configured as at least one fixed predetermined value. For example, at least one tDAI is required for each DAI bit number in at least one DAI bit number, and the at least one DAI bit number may be configured with at least one 4 bits. In step 605, NE 620 may determine the DAI by modulo 4 operation, for example, based on cDAI and / or tDAI. In some embodiments, after NE 620 determines that the DAI bit number is not configured, or the DAI bit number is configured as 2 bits, NE 620 may determine the DAI by modulo 4 operation based on a global or local count, wherein the global or local count has the same configuration order for PDCCH PDCCH monitoring opportunities from different TRPs. For example, each PDCCH may include only 2 bits for indicating a PDCCH count index, i.e., cDAI.

[0040] In some embodiments, NE 620 may configure at least one reference TRP index associated with high-layer signaling. For example, NE 620 may select at least one reference TRP having a channel quality exceeding at least one predetermined threshold, which is configured to improve NE 620's detection of lost PDCCH. NE 620 may determine channel quality based on at least one L3-RSRP measurement result. For each PDCCH from at least one different TRP in at least one PDCCH monitoring opportunity, at least one PDCCH from at least one TRP is delayed and counted. For example, DAI may be determined based in part on at least one cumulative number of PDCCHs, where the actual index may be related to a counting sequence. Therefore, a PDCCH received from a TRP associated with a lower channel quality may be counted before a TRP associated with a higher channel quality. In some embodiments, local counting may be used for a first TRP with a lower channel quality, while global counting may be used for a second TRP with a higher channel quality.

[0041] like Figure 4 As shown, TRP2 can be a reference TRP based on channel quality exceeding at least one predetermined threshold. In various embodiments, within at least one PDCCH monitoring opportunity, at least one PDCCH from TRP2 can be counted after receiving at least one PDCCH from TRP1. For example, if the PDCCH with cDAI=7 is lost, the UE 630 may not know whether there is an actual PDCCH transmission because it is the last PDCCH. In response, when the PDCCH with cDAI=7 comes from a reference TRP with channel conditions exceeding at least one predetermined threshold, this can reduce the probability of PDCCH loss to below at least one predetermined threshold.

[0042] In some embodiments, the NE 620 may count at least one PDCCH. For example, at least one local index may be used for the DAI, where a TRP-specific separate PDCCH count is used for at least one other TRP, for example, at least one TRP different from the reference TRP. Additionally or alternatively, a global index may be configured for the DAI with a joint PDCCH count for the reference TRP. As a result, this may provide a missed detection capability exceeding at least one predetermined threshold configured as the DAI of the secondary reference TRP. In addition, as Figure 4 As shown, when UE 630 does not receive PDCCH of cDAI=6 / 3 but receives PDCCH of cDAI=5 and cDAI=7, UE 630 can be configured to know the lack of PDCCH of cDAI=6 / 3 and have no problem in determining at least one HARQ-ACK codebook size.

[0043] In some embodiments, at least one DAI indication bit may be determined based on at least one counter DAI having a modulo operation of 4 due to a 2-bit indication. In some embodiments, the NE 620 may configure at least one counting order of PDCCHs in at least one PDCCH monitoring opportunity from at least one different TRP associated with at least one higher-level signaling for the UE 630. In some embodiments, a local count may be used for a first TRP having a lower channel quality, while a global count may be used for a second TRP having a higher channel quality.

[0044] For example, a PDCCH from at least one TRP having a channel quality above at least one predetermined threshold may be counted later than at least one PDCCH from at least one TRP having a channel quality below at least one predetermined quality in order to better detect at least one lost PDCCH

[0045] In some embodiments, channel quality may be determined based on at least one L3-RSRP measurement result. For at least one PDCCH from at least one different CORESET group, the counting order may be sorted according to at least one channel quality, for example, PDCCHs from TRPs with improved channels may be postponed for counting. For example, the DAI may be determined based in part on at least one cumulative number of PDCCHs, where the actual index may be related to the counting sequence. Thus, a PDCCH received from a TRP associated with a lower channel quality may be counted before a TRP associated with a higher channel quality. In some embodiments, local counting may be used for a first TRP with a lower channel quality, while a global count may be used for a second TRP with a higher channel quality. For PDCCHs from the same CORESET group, the counting order may be sorted according to at least one CORESET index, for example, at least one PDCCH in the CORESET with at least one larger index may be counted later.

[0046] Reference Figure 5 , within the PDCCH monitoring occasion, the PDCCH from TRP2 may be counted after the PDCCH from TRP1 because the PDCCH from TRP2 may have better channel conditions. For example, if at least one PDCCH with cDAI=7 is missing, the UE 630 may not know whether there is at least one actual PDCCH transmission because it is the last PDCCH. When at least one PDCCH cDAI=7 is from a TRP and the channel condition exceeds at least one predetermined threshold, there may be a lower probability that at least one PDCCH is lost.

[0047] In some embodiments, NE 620 may be configured for a global count of at least one PDCCH. For example, at least one global index may be configured for the DAI based on the joint count, which may provide improved cross-checking and detection of lost PDCCHs between TRPs. Figure 5 As shown, when UE 630 does not receive at least one PDCCH with cDAI=6, but receives at least one PDCCH with cDAI=7, UE 630 may know that the PDCCH with cDAI=6 may be lost, and / or there may be an improved ability to determine the HARQ-ACK codebook size. NE 620 may determine at least one DAI bit based on at least one cDAI based on a joint count and a modulo operation of 4.

[0048] In step 607, the NE 620 may configure a plurality of PDCCHs associated with the plurality of TRPs, wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field including at least one DAI.

[0049] In step 609, the NE 620 may send at least one PDCCH associated with at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme to the UE 630. For example, the NE 620 may send multiple PDCCHs from different TRPs / CCs.

[0050] In step 611, upon receiving at least one PDCCH with a DAI according to at least one proposed counting scheme, the UE 630 may detect at least one missing PDCCH, for example, based on at least one DAI bit.

[0051] In step 613, the UE 630 may determine at least one HARQ-ACK codebook size. For example, for the ACK / NACK bits corresponding to the PDSCH scheduled by the lost PDCCH, the UE 630 may directly set NACK.

[0052] Figure 7 The diagram shows the network entities (such as Fig. 9 9. In step 701, the network entity may determine whether at least one carrier aggregation is configured. For example, when it is determined that CA is not configured, the network entity may be configured to configure a DAI with a bit number of 2 or 4 based on, for example, channel quality. In various embodiments, the network entity may be configured to configure a 4-bit DAI for at least one cell edge user in response to at least one lost PDCCH detection capability of the network entity exceeding at least one performance threshold. Additionally or alternatively, a user equipment, such as Fig. 9 UE 920 in the Fig. 9 As shown, it can be configured to configure a 2-bit DAI for at least one cell center user in response to at least one probability of PDCCH loss being lower than at least one predetermined threshold.

[0053] In step 703, the network entity may determine whether at least one DAI bit number is configured. In step 705, the network entity may determine at least one DAI, for example, based on the cDAI by modulo 4 operation. In some embodiments, when the network entity determines that the number of DAI bits is not configured, or the number of DAI bits is configured as 2 bits, the network entity may determine the DAI by modulo 4 operation based on a global count, and the global count has a configuration order for at least one PDCCH detection opportunity from different TRPs. For example, each PDCCH may include only 2 bits for indicating a PDCCH count index, i.e., cDAI.

[0054] In some embodiments, the network entity may configure at least one reference TRP index associated with higher layer signaling. For example, the network entity may select at least one reference TRP whose channel quality exceeds at least one predetermined threshold, which is configured to improve the network entity's detection of lost PDCCHs. The network entity may determine the channel quality based on at least one L3-RSRP measurement result. For each PDCCH from at least one different TRP in at least one PDCCH monitoring opportunity, at least one PDCCH from at least one TRP is delayed and counted. For example, the DAI may be determined based in part on at least one cumulative number of PDCCHs, where the actual index may be related to the counting sequence. Therefore, a PDCCH received from a TRP associated with a lower channel quality may be counted before a TRP associated with a higher channel quality. In some embodiments, local counting may be used for a first TRP with a lower channel quality, while global counting may be used for a second TRP with a higher channel quality.

[0055] like Figure 4 As shown, TRP2 can be a reference TRP based on channel quality exceeding at least one predetermined threshold. In various embodiments, within at least one PDCCH monitoring opportunity, at least one PDCCH from TRP2 can be counted after receiving at least one PDCCH from TRP1. For example, if a PDCCH with cDAI=7 is missing, the UE may not know whether there is an actual PDCCH transmission because it is the last PDCCH. In response, when a PDCCH with cDAI=7 comes from a reference TRP where channel conditions exceed at least one predetermined threshold, this can reduce the probability of PDCCH loss to below at least one predetermined threshold.

[0056] In some embodiments, the NE may count at least one PDCCH. For example, at least one local index may be used for the DAI, where a TRP-specific separate PDCCH count is used for at least one other TRP, for example, at least one TRP that is different from a reference TRP. Additionally or alternatively, a global index may be configured for the DAI with a joint PDCCH count for the reference TRP. As a result, this may provide a missed detection capability exceeding at least one predetermined threshold, which is configured as the DAI of the secondary reference TRP. In addition, when the UE does not receive a PDCCH with cDAI=6 / 3 but receives a PDCCH with cDAI=5 and cDAI=7, the UE may be configured to know that the PDCCH with cDAI=6 / 3 is lost and there is no problem determining at least one HARQ-ACK codebook size.

[0057] In some embodiments, at least one DAI indication bit may be determined based on at least one counter DAI having a modulo operation of 4 due to a 2-bit indication. In some embodiments, the NE may configure for the UE at least one counting order of PDCCHs in at least one PDCCH monitoring occasion from at least one different TRP associated with at least one higher level signaling.

[0058] For example, a PDCCH from at least one TRP having a channel quality above at least one predetermined threshold may be counted later than at least one PDCCH from at least one TRP having a channel quality below at least one predetermined quality in order to better detect at least one lost PDCCH

[0059] In some embodiments, channel quality may be determined based on at least one L3-RSRP measurement result. For at least one PDCCH from at least one different CORESET group, the counting order may be sorted according to at least one channel quality, for example, PDCCHs from TRPs with improved channels may be postponed for counting. For example, the DAI may be determined based in part on at least one cumulative number of PDCCHs, where the actual index may be related to the counting sequence. Thus, a PDCCH received from a TRP associated with a lower channel quality may be counted before a TRP associated with a higher channel quality. In some embodiments, local counting may be used for a first TRP with a lower channel quality, while a global count may be used for a second TRP with a higher channel quality. For PDCCHs from the same CORESET group, the counting order may be sorted according to at least one CORESET index, for example, at least one PDCCH in the CORESET with at least one larger index may be counted later.

[0060] Reference Figure 5, during the PDCCH monitoring opportunity, the PDCCH from TRP2 can be counted after the PDCCH from TRP1 because the PDCCH from TRP2 may have better channel conditions. For example, if at least one PDCCH with cDAI=7 is missing, the UE may not know whether there is at least one actual PDCCH transmission because it is the last PDCCH. When at least one PDCCH cDAI=7 is from a TRP and the channel condition exceeds at least one predetermined threshold, there may be a lower probability that at least one PDCCH is lost.

[0061] In some embodiments, the NE may be configured for a global count of at least one PDCCH. For example, at least one global index may be configured for the DAI based on the joint count, which may provide improved cross-checking and detection of lost PDCCHs between TRPs. Figure 5 , when the UE does not receive at least one PDCCH with cDAI=6 but receives at least one PDCCH with cDAI=7, the UE may realize that the PDCCH with cDAI=6 may be lost and / or there may be an improved ability to determine the HARQ-ACK codebook size. The NE may determine at least one DAI bit based on the joint count with the modulo operation of 4 according to at least one cDAI.

[0062] In step 707, the NE may configure a plurality of PDCCHs associated with a plurality of TRPs, wherein each TRP corresponds to each PDCCH, and wherein each PDCCH includes at least one downlink control information (DCI) field, the DCI field including at least one DAI.

[0063] In step 709, the NE may send at least one PDCCH with DAI to the UE according to at least one proposed counting scheme. For example, the NE may send multiple PDCCHs from different TRPs / CCs.

[0064] Figure 8 The diagram shows the Fig. 9 An example of a method performed by a user equipment of the user equipment 920 in step 801. In step 801, the UE may receive at least one PDCCH associated with at least one DAI according to at least one local DAI counting scheme and / or at least one global DAI counting scheme, wherein the received PDCCH includes at least one DCI field including at least one DAI from a NE, e.g. Fig. 9 NE 910 in. For example, the UE may receive multiple PDCCHs from different TRP / CCs.

[0065] In step 803, upon receiving at least one PDCCH with a DAI according to at least one proposed counting scheme, the UE may detect at least one lost PDCCH, for example based on at least one DAI bit. In step 805, the UE may determine at least one HARQ-ACK codebook size. For example, for the ACK / NACK bit corresponding to the PDSCH scheduled by the lost PDCCH, the UE may directly set NACK.

[0066] Fig. 9 An example of a system according to some example embodiments is shown.In an example embodiment, a system may include a plurality of devices, such as, for example, a network entity 910 and / or a user equipment 920 .

[0067] The network entity 910 may be one or more of: a base station (such as a millimeter wave antenna, an evolved Node B (eNB) or a 5G or new radio Node B (gNB)), a serving gateway, a server, and / or any other access node, or a combination thereof. In addition, the network entity 910 and / or the user equipment 920 may be one or more of a Citizen Broadband Radio Service Device (CBSD).

[0068] User device 920 may include one or more of the following: a mobile device (such as a mobile phone, a smart phone, a personal digital assistant (PDA), a tablet device, or a portable media player), a digital camera, a camcorder, a video game console, a navigation unit (such as a global positioning system (GPS) device), a desktop or laptop computer, a single location device (such as a sensor or smart meter), or any combination thereof.

[0069] One or more of these devices may include at least one processor, represented as 911 and 921, respectively. Processors 911 and 921 may be implemented by any computing or data processing device, such as a central processing unit (CPU), an application specific integrated circuit (ASIC), or a similar device. The processor may be implemented as a single controller or multiple controllers or processors.

[0070] At least one memory may be provided in one or more of the devices indicated by 912 and 922. The memory may be fixed or removable. The memory may include computer program instructions or computer codes contained therein. The memories 912 and 922 may be independently any suitable storage device, such as a non-transient computer readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory or other suitable memory may be used. The memory may be combined on a single integrated circuit as a processor, or may be separated from one or more processors. In addition, the computer program instructions stored in the memory and processable by the processor may be computer program codes in any suitable form, for example, a compiled or interpreted computer program written in any suitable programming language. The memory may be removable or non-removable.

[0071] Processors 911 and 921 and memories 912 and 922 or a subset thereof may be configured to provide Figures 1 to 8 Components corresponding to the various blocks of. Although not shown, the device may also include positioning hardware, such as GPS or micro-electromechanical system (MEMS) hardware, which can be used to determine the location of the device. Other sensors are also allowed and can be included to determine the location, altitude, orientation, etc., such as a barometer, compass, etc.

[0072] like Fig. 9 As shown, transceivers 913 and 923 may be provided, and one or more devices may also include at least one antenna, shown as 914 and 924, respectively. The device may have many antennas, such as an antenna array configured for multiple input multiple output (MIMO) communication, or multiple antennas for multiple radio access technologies. For example, other configurations of these devices may be provided. Transceivers 913 and 923 may be transmitters, receivers, or both transmitters and receivers, or may be configured for units or devices that transmit and receive.

[0073] The memory and the computer program instructions may be configured to cause a hardware device such as a user device to perform any of the processes described below using a processor for a particular device (see, for example, Figure 1-8 ). Thus, in certain example embodiments, a non-transitory computer readable medium may be encoded with computer instructions that, when executed in hardware, perform a process such as one of the processes described herein. Alternatively, certain example embodiments may be performed entirely in hardware.

[0074] In certain example embodiments, the apparatus may include a Figures 1 to 8. For example, the circuit may be a pure hardware circuit implementation, such as an analog and / or digital circuit. In another example, the circuit may be a combination of hardware circuits and software, such as (multiple) analog and / or digital hardware circuits with software or firmware, and / or any part of (multiple) hardware processors with software (including (multiple) digital signal processors), software, and at least one memory, which work together to enable the device to perform various processes or functions. In yet another example, the circuit may be (multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or a part of (multiple) microprocessors, which include software, such as firmware for operation. When the hardware operation does not require software, the software in the circuit may not exist.

[0075] The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in one or more embodiments in any suitable manner. For example, the use of the phrases "certain embodiments," "some embodiments," "other embodiments," or other similar language throughout this specification refers to the fact that a specific feature, structure, or characteristic described in conjunction with an embodiment may be included in at least one embodiment of the present invention. Therefore, the phrases "in certain embodiments," "in some embodiments," "in other embodiments," or other similar language appearing throughout this specification do not necessarily refer to the same set of embodiments, and the described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner.

[0076] Those of ordinary skill in the art will readily appreciate that the present invention as discussed above can be practiced with steps in different orders and / or with hardware elements of configurations different from the disclosed configurations. Therefore, although the present invention has been described based on these preferred embodiments, it is obvious to those skilled in the art that certain modifications, variations, and alternative structures will be apparent while remaining within the spirit and scope of the present invention. The above embodiments may be applied to any communication network or wireless system. Although many of the above embodiments relate to LTE or LTE-A, other embodiments may be used for 3GPP fifth generation (5G) technology, fourth generation (4G) technology, new radio (NR) technology, and / or any wireless terrestrial access network (WLAN).

[0077] Partial Glossary

[0078] 3GPP Third Generation Partnership Project

[0079] 5G Fifth Generation Wireless System

[0080] ACK

[0081] CA Carrier Aggregation

[0082] CC Component Carrier

[0083] cDAI counter dynamically allocated index

[0084] CORESET Control Resource Set

[0085] DAI Dynamic Allocation Index

[0086] DCI Dynamic Control Indicator

[0087] eMBB Enhanced Mobile Broadband

[0088] eNB Evolved Node B

[0089] E-UTRAN Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network

[0090] gNB Next Generation Node B

[0091] HARQ Hybrid Automatic Repeat Request

[0092] LTE Long Term Evolution

[0093] MAC Media Access Control

[0094] MIMO Multiple Input Multiple Output

[0095] NACK Negative Acknowledgement

[0096] NCJT Non-coherent joint transmission

[0097] NE Network Entity

[0098] NR New Radio

[0099] PDCCH Physical Downlink Control Channel

[0100] PDSCH Physical Downlink Shared Channel

[0101] PUSCH Physical Uplink Control Channel

[0102] REL Release

[0103] tDAI Total Dynamic Allocation Index

[0104] TRP Transmission Reception Point

[0105] UE User Equipment

[0106] UL Uplink

[0107] WI Work Items

Claims

1. A device for communication, comprising: at least one processor; as well as at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to: configuring a plurality of physical downlink control channels (PDCCHs) associated with a plurality of transmission reception points (TRPs), wherein each TRP corresponds to each PDCCH, and wherein each PDCCH comprises at least one downlink control information (DCI) field, wherein the DCI field comprises at least one downlink assignment index (DAI); as well as transmitting at least one PDCCH associated with the at least one DAI according to at least one local DAI counting scheme and at least one global DAI counting scheme or according to the at least one global DAI counting scheme, The global DAI counting scheme is configured to start counting in order from the PDCCH on the TRP with the worst channel quality to the PDCCH on the TRP with the best channel quality.

2. An apparatus according to claim 1, wherein the at least one local DAI counting scheme is configured to count each PDCCH in multiple PDCCHs on multiple TRPs individually, and the at least one global DAI counting scheme is configured to count multiple PDCCHs on multiple TRPs as a single count.

3. The apparatus of claim 1, wherein the at least one global DAI counting scheme takes into account a channel quality between the TRP and the user equipment.

4. An apparatus according to claim 1, wherein at least one reference TRP is associated with at least one channel quality, and the at least one channel quality exceeds at least one channel quality of at least one other TRP.

5. The apparatus of claim 1, wherein a global PDCCH index is used in the DAI of a reference TRP to provide a check capability for lost PDCCHs from other TRPs.

6. The device according to claim 1, wherein after the device determines that the number of DAI bits is configured as 4 bits or CA is not configured, the device also determines the DAI based on a 3-dimensional count using a modulo 4 operation, and the 3-dimensional count has the following order: first TRP, then component carrier, and then at least one PDCCH monitoring opportunity index.

7. An apparatus according to claim 1, wherein after the apparatus determines that a 4-bit DAI bit number is not configured or a 2-bit DAI bit number is configured, the apparatus further determines the DAI based on a global count using a modulo 4 operation, wherein the global count has an order of configuration for the at least one PDCCH detection opportunity from different TRPs.

8. The apparatus of claim 1, wherein the at least one global DAI counting scheme is configured to count based on at least one 2-bit indication, and the at least one local DAI counting scheme is configured to count based on at least one 2-bit indication. 9 . The apparatus according to claim 1 , wherein after determining that CA is not configured, the apparatus further configures a bit number of 2 or 4 for DAI according to channel quality.

10. The apparatus according to any one of claims 1-9, wherein the apparatus further determines whether at least one dynamic allocation index (DAI) bit number is configured.

11. An apparatus for communication, comprising: at least one processor; as well as at least one memory including computer program code, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to: Receiving at least one physical downlink control channel (PDCCH) associated with at least one DAI according to at least one local dynamic allocation index (DAI) counting scheme and at least one global DAI counting scheme or according to the at least one global DAI counting scheme, wherein the received PDCCH includes at least one downlink control information (DCI) field, the DCI field includes at least one downlink allocation index (DAI), and wherein the global DAI counting scheme is configured to start counting in order from the PDCCH on the TRP with the worst channel quality to the PDCCH on the TRP with the best channel quality; detecting at least one lost detected PDCCH; and At least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size is determined.

12. The apparatus of claim 11, wherein the at least one local DAI counting scheme is configured to count each PDCCH in a plurality of PDCCHs on a plurality of TRPs individually, and the at least one global DAI counting scheme is configured to count a plurality of PDCCHs on a plurality of TRPs as a single count.

13. The apparatus of claim 11, wherein the at least one global DAI counting scheme takes into account a channel quality between the TRP and the user equipment.

14. The apparatus of claim 11, wherein the at least one reference TRP is associated with at least one channel quality that exceeds at least one channel quality of at least one other TRP.

15. An apparatus according to any one of claims 11-14, wherein a global PDCCH index is used in the DAI of a reference TRP to provide a check capability for lost PDCCHs from other TRPs.

16. A method of communication, said method being according to any one of claims 1-15.

17. A non-transitory computer readable medium encoding instructions which, when executed in hardware, perform a process according to any one of claims 1-15.

18. An apparatus for communication, comprising means for performing a procedure according to any one of claims 1-15.

19. An apparatus for communication, comprising circuitry configured to cause the apparatus to perform a process according to any one of claims 1-15.

20. A computer program product encoded with instructions for performing a process according to any one of claims 1-15.

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