CN114503720A

CN114503720A - DAI scheme for joint ACK/NACK feedback in multiple TRP/panel transmission

Info

Publication number: CN114503720A
Application number: CN201980100771.9A
Authority: CN
Inventors: 张翼; K·S·J·拉杜
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2019-09-25
Filing date: 2019-09-25
Publication date: 2022-05-13
Also published as: WO2021056264A1

Abstract

According to some embodiments, an apparatus includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus 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 apparatus also transmits 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.

Description

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

Technical Field

Certain embodiments may relate to a communication system. For example, some embodiments may relate to multiple Transmission Reception Point (TRP)/panel transmission.

Background

Under the third generation partnership project (3GPP), release 16 (Rel-16) Work Item (WI) includes enhancements to Multiple Input Multiple Output (MIMO). Multiple TRP/panel transmissions are considered an important part of NR deployment because of their ability to facilitate enhanced mobile broadband (eMBB) operation, as well as to improve reliability of ultra-reliable low latency communication (URLLC) services. For example, WI in relation to MIMO enhancements notes that enhancements to multiple TRP/panel transmissions include increased reliability and robustness through ideal and non-ideal backhauls. These enhancements may include specifying downlink control signaling enhancements for efficient support of non-coherent joint transmission and enhancements for uplink control signaling and/or reference signal(s) for non-coherent joint transmission.

Disclosure of Invention

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 including at least one Downlink Allocation Index (DAI). The method may also include transmitting, by the 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.

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 Assignment Index (DAI). The apparatus may also include means for transmitting at least one PDCCH associated with at least one DAI in accordance with at least one local DAI counting scheme and/or at least one global DAI counting scheme.

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, with the at least one processor, to cause the apparatus at least 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 at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus at least to transmit at least one PDCCH associated with the at least one DAI and/or at least one global DAI counting scheme according to at least one local DAI counting scheme.

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 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 method 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.

According to some embodiments, a computer program product may perform a method. The method may 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 method 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.

In accordance with 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 Assignment Index (DAI). The circuitry may also transmit at least one PDCCH associated with at least one DAI in accordance with at least one local DAI counting scheme and/or at least one global DAI counting scheme.

According to some embodiments, a method may include receiving, by a user equipment, at least one Physical Downlink Control Channel (PDCCH) and/or at least one global DAI counting scheme associated with at least one Dynamic Allocation Index (DAI) according to at least one local 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 also include detecting, by the user equipment, the at least one missed detected PDCCH. The method may also include determining, by the user equipment, at least one hybrid automatic repeat request-acknowledgement (HARQ-ACK) codebook size.

According to some embodiments, an apparatus may include means for receiving a PDCCH including at least one Downlink Control Information (DCI) field including at least one Downlink Assignment Index (DAI) according to at least one local DAI counting scheme and/or at least one global DAI counting scheme. The apparatus may also include means for detecting at least one missed detected PDCCH. The apparatus may also include means for determining at least one hybrid automatic repeat request-acknowledgement (HARQ-ACK) codebook size.

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, with the at least one processor, cause the apparatus at least 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 including at least one Downlink Allocation Index (DAI). The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus at least to detect at least one missed detected PDCCH. The at least one memory and the computer program code may also be configured to, with the at least one processor, cause the apparatus at least to determine at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size.

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 missed detected PDCCH. The method may further determine at least one hybrid automatic repeat request-acknowledgement (HARQ-ACK) codebook size.

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 missed detected PDCCH. The method may further determine at least one hybrid automatic repeat request-acknowledgement (HARQ-ACK) codebook size.

According to some embodiments, an apparatus may include a receiver configured to receive at least one Physical Downlink Control Channel (PDCCH) and/or at least one global DAI counting scheme associated with at least one Dynamic Allocation Index (DAI) according to at least one local 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 circuitry may further detect at least one missed detected PDCCH. The circuitry may further determine at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook size.

Drawings

For a proper understanding of the present disclosure, reference should be made to the accompanying drawings, in which:

fig. 1 shows an example of PDCCH scheduling transmission of NR-PDSCH from various TRPs.

Fig. 2 shows an example of individual counts for a plurality of TRP transmissions.

Fig. 3 shows an example of no detection capability, where a bursty PDCCH is lost due to being blocked by a TRP.

Fig. 4 illustrates an example of an optimization scheme based on local/joint counting and higher layer signaling for reference TRP according to some embodiments.

Fig. 5 illustrates another example of an optimization scheme based on joint counting and higher layer signaling for counting order between TRPs, according to some embodiments.

Fig. 6 illustrates a signaling diagram in accordance with some embodiments.

Fig. 7 illustrates an example of a method performed by a network entity, in accordance with certain embodiments.

Fig. 8 illustrates an example of a method performed by a user equipment, according to some embodiments.

FIG. 9 illustrates an example of a system according to some embodiments.

Detailed Description

During the 3GPP Radio Access Network (RAN) Working Group (WG)1, two techniques are agreed to support multiple TRP transmission in NR, specifically, a single PDCCH design and multiple PDCCH designs. A single PDCCH schedules one DPSCH, where separate layers are transmitted from separate TRPs, while multiple PDCCHs each schedule a corresponding PDSCH, where each NR-PDSCH is transmitted from a separate TRP. In multiple PDCCH designs, multiple PDCCHs from multiple TRPs may schedule respective multiple PDSCHs. The transmission of multiple PDCCHs may occur independently of the two TRPs. This can therefore be used for both ideal and non-ideal backhaul.

Conference No. 3GPP RAN 197 agreed an agreement that joint HARQ-ACK feedback for multiple DCIs can be supported, and type 1 and type 2HARQ-ACK codebooks can be supported. Specifically, for separate ACK/NACK feedback of PDSCH received from different TRPs, if indexes are configured and applied to all CCs, the UE should be able to generate a separate ACK/NACK codebook identified by the indexes. Furthermore, joint HARQ-ACK feedback may be supported for PDSCH received from different TRPs using multiple DCI. When the PUCCH resources are at different PDCCH monitoring occasions, which are indicated by PDSCH-to-HARQ feedback timing indicator fields of multiple DCIs for different TRPs, both type 1 and type 2HARQ-ACK codebooks are supported.

Further, for multi-TRP operation based on multiple PDCCHs, one CORESET in "PDCCH-config" may correspond to one TRP. After 3GPP RAN 196 and RAN 197, one CORESET in "PDCCH-config" corresponds to one TRP in order to support multiple TRP/panel transmission based on multiple PDCCHs through the intra-cell (i.e., same cell ID) in order to link multiple PDCCH/PDSCH pairs with multiple TRPs.

In addition, for multi-TRP operation based on multiple PDCCH, the maximum number of CORESET per "PDCCH-config" may be increased to 5. This TRP difference may be used for an enhanced DAI indication for adding ACK/NACK feedback when multiple TRP transmissions with multiple DCIs occur.

According to the Rel-15 DAI indication scheme, a dynamic codebook, such as a type II codebook, may reduce codebook size relative to a semi-static codebook and may be an improvement over error-free in downlink control signaling. However, in case of loss detection of downlink control signaling, the NE and the UE may interpret the codebook size in a different way and may further result in corrupted feedback reports at least for the lost downlink control signaling. For example, the UE may be scheduled for downlink transmission in the next two PDCCH monitoring occasions, but miss the first PDCCH, and therefore the UE may send an acknowledgement only for the PDSCH scheduled by the second PDCCH monitoring occasion. Instead, the NE may attempt to receive an acknowledgement for both PDCCH monitoring occasions and a mismatch occurs. In response to these errors, a Downlink Assignment Index (DAI) may be used in the downlink DCI. The DAI field may be further divided into two parts, a counter DAI (cdai) and an optional total DAI for carrier aggregation (tdai). A counter DAI included in DCI may indicate the number of currently scheduled downlink transmissions, where DCI is first ordered by carrier and then by time. The total DAI included in the DAIs included in the DCI may indicate a total number of downlink transmissions across all carriers by the current PDCCH monitoring occasion.

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

For non-coherent joint transmission (NCJT), the PDSCH may be transmitted from multiple TRPs through multiple PDCCH scheduling. For an ideal backhaul or a non-ideal backhaul with small latency, ACK/NACK bits may be jointly returned. The number of HARQ-ACK bits of the dynamic HARQ-ACK codebook may be determined based on the actual PDSCH from the carrier and PDCCH loss. However, the 3GPP Rel-15 DAI indication scheme is not sufficient to correct missing PDCCH, which may originate from multiple TRPs. Extensions can be added to 3GPP Rel-15 independently for each TRP, but not without some drawbacks. For example, such an extension scheme would not provide cross-checking capability between TRPs for a missing PDCCH. For example, as shown in fig. 2, cDAI information in the PDCCH from TRP2 will not support detection of the missing PDCCH from TRP 1.

Furthermore, there is no ability to identify the last few missed PDCCHs. Due to the increased number of TRPs, the number of undetected missed PDCCHs will increase. Referring again to fig. 2, if the second PDCCH from TRP1 is missed by the UE, it may be detected because the UE may receive the cDAI information from the third PDCCH received from TRP 1. 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 have no DAI information available for reference. For multiple TRP transmissions, the last PDCCH is from multiple TRP perspectives, increasing the number of PDCCH missed detections.

However, a DAI indication scheme with joint PDCCH counts from multiple TRPs may be used to address the above disadvantages, as this includes cross-checking capability to detect missing PDCCH, and only one "last" DCI from the joint HARQ-ACK codebook angle. The DAI from a PDCCH with improved channel quality may also provide a missed check for a PDCCH with poor channel quality.

For multiple TRP transmissions, one situation in frequency range 2(FR2) may occur 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, 4 consecutive missed PDCCHs cannot be detected. As shown in fig. 3, a PDCCH scheduling 4 CCs from one TRP may be lost due to blocking, and according to the current Rel-15 DAI design, the UE does not know that there is PDCCH transmission. Therefore, a special design utilizing count information from another TRP may be used to provide the ability to detect bursty PDCCH impairments.

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 to use for the non-CA case. PDCCH reliability may be enhanced by a smaller number of DAI bits, while the detection capability for missed PDCCHs may be enhanced by more DAI bits (such as 4 bits). For a joint HARQ-ACK having multiple PDCCHs from multiple TRPs, the number of PDCCHs indicating the count of DAIs may be increased by the multiple TRPs. Therefore, there is a need for an enhancement scheme that balances the lost PDCCH detection capability with the DAI signaling overhead, which can exploit the channel quality differences between TRPs. The 2-bit and 4-bit DAI signaling schemes may then be switched using higher layer signaling based on the channel quality.

Certain embodiments described herein may provide DAI enhancements that enable improvements between signaling overhead and the ability to detect lost PDCCH with 2-bit DAI for non-CA scenarios. Furthermore, PDCCH loss detection capability may be improved for the CA case or the DAI case for joint ACK/NACK feedback by multiple DCI transmission from multiple TRPs for non-CA over 4 bits. Accordingly, certain embodiments relate to improvements to computer related techniques, in particular enabling DAI indication to guarantee the same understanding of HARQ-ACK codebook size between a network entity and a user equipment. Some embodiments may also conserve network resources and reduce power consumption by network entities and/or user equipment located within the network by reducing redundant operations.

Fig. 6 illustrates an example of a signaling diagram in accordance with some embodiments. Network Entity (NE)620 may be similar to NE 910 in fig. 9, and User Equipment (UE)630 may be similar to UE 920 in 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.

In step 601, NE 620 may determine whether at least one carrier aggregation is configured. For example, after determining that CA is not configured, NE 620 may be configured to configure the number of

bits

2 or 4 for DAI according to, for example, channel quality. In various embodiments, NE 620 may be configured to configure a 4-bit DAI for at least one cell edge user in response to at least one missed PDCCH detection capability of NE 620 exceeding at least one performance threshold. Additionally or alternatively, 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 missed being below at least one predetermined threshold.

In step 603, NE 620 may determine whether at least one DAI bit number is configured. For example, the at least one DAI bit number may be configured to be at least one fixed predetermined value. For example, at least one tDAI is required for each of at least one number of DAI bits, which may be configured with at least one 4-bit. In step 605, NE 620 may determine the DAI by modulo 4 arithmetic, for example, from the cDAI and/or tDAI. In some embodiments, after NE 620 determines that no DAI bit number is configured, or the DAI bit number is configured to 2 bits, NE 620 may determine the DAI by modulo-4 operation based on a global or local count with PDCCH monitoring occasions from different TRPs in the same configuration order for the PDCCH. For example, each PDCCH may include only 2 bits for indicating a PDCCH count index, i.e., cDAI.

In some embodiments, NE 620 may configure at least one reference TRP index associated with higher layer signaling. For example, NE 620 may select at least one reference TRP having a channel quality exceeding at least one predetermined threshold configured to improve the detection of missed PDCCHs by NE 620. NE 620 may determine the channel quality based on at least one L3-RSRP measurement. For each PDCCH from at least one different TRP in at least one PDCCH monitoring occasion, at least one PDCCH from the at least one TRP is delay counted. For example, the DAI may be determined based in part on at least one cumulative PDCCH number, where the actual index may be related to the count sequence. Thus, PDCCHs received from TRPs associated with lower channel qualities may be counted before TRPs associated with higher channel qualities. In some embodiments, the local count may be for a first TRP having a lower channel quality and the global count may be for a second TRP having a higher channel quality.

As shown in fig. 4, TRP2 may be a reference TRP based on a channel quality exceeding at least one predetermined threshold. In various embodiments, within the at least one PDCCH monitoring machine, the at least one PDCCH from TRP2 may be counted after the at least one PDCCH is received from TRP 1. For example, if a PDCCH with cDAI of 7 is missed, 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 is from a reference TRP with channel conditions exceeding at least one predetermined threshold, this may reduce the probability of PDCCH missed below the at least one predetermined threshold.

In some embodiments, NE 620 may count at least one PDCCH. For example, at least one local index may be used for the DAI, wherein the TRP-specific separate PDCCH count is used for at least one other TRP, e.g., at least one TRP different from the reference TRP. Additionally or alternatively, the global index may be configured for DAI and have a joint PDCCH count for the reference TRP. As a result, this may provide a missed detection capability that exceeds at least one predetermined threshold configured to assist in referencing the DAI of the TRP. Further, as shown in fig. 4, when the UE 630 does not receive the PDCCH of cDAI-6/3 but receives the PDCCHs of cDAI-5 and cDAI-7, the UE 630 may be configured to know that the PDCCH of cDAI-6/3 is absent and there is no problem for determining at least one HARQ-ACK codebook size.

In some embodiments, the at least one DAI indication bit may be determined based on at least one counter DAI having a modulo operation of 4 due to the 2-bit indication. In some embodiments, NE 620 may configure UE 630 with 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. In some embodiments, the local count may be used for a first TRP having a lower channel quality and the global count may be used for a second TRP having a higher channel quality.

For example, a PDCCH from at least one TRP having a channel quality above at least one predetermined threshold may be counted better 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 missing PDCCH

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

Referring to fig. 5, in the PDCCH monitoring machine, 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 absent, UE 630 may not know whether there is at least one actual PDCCH transmission because it is the last PDCCH. There may be a lower probability of at least one PDCCH being missed when the at least one PDCCH cDAI is from the TRP at 7 and the channel condition exceeds at least one predetermined threshold.

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 ability to cross-check between TRPs and detect missing PDCCH. As shown in fig. 5, when the UE 630 does not receive at least one PDCCH with cDAI of 6 but receives at least one PDCCH with cDAI of 7, the UE 630 may know that the PDCCH with cDAI of 6 may be lost and/or there may be an improved capability of determining the HARQ-ACK codebook size. NE 620 may determine at least one DAI bit from the at least one cDAI based on the joint count and a modulo operation of 4.

In step 607, NE 620 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 including at least one DAI.

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

In step 611, upon receiving at least one PDCCH with a DAI according to at least one proposed counting scheme, UE 630 may detect at least one missed PDCCH, e.g., based on at least one DAI bit.

In step 613, the UE 630 may determine at least one HARQ-ACK codebook size. For example, UE 630 may directly set a NACK for the ACK/NACK bit corresponding to the PDSCH scheduled by the missed PDCCH.

Fig. 7 illustrates an example of a method performed by a network entity (e.g., network entity 910 in fig. 9). 9. In step 701, the network entity may determine whether at least one carrier aggregation is configured. For example, upon determining that CA is not configured, the network entity may be configured to configure

bit numbers

2 or 4 for the DAI according to, 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 missed PDCCH detection capability of the network entity exceeding at least one performance threshold. Additionally or alternatively, a user equipment, such as UE 920 in fig. 9. As shown in fig. 9, 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 missed being below at least one predetermined threshold.

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 by modulo-4 operation, for example, according to the cDAI. 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 to be 2 bits, the network entity may determine the DAI by modulo 4 operation based on a global count having a configured order for at least one PDCCH detection occasion from different TRPs. For example, each PDCCH may include only 2 bits for indicating a PDCCH count index, i.e., cDAI.

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 having a channel quality exceeding at least one predetermined threshold configured to improve detection of missed PDCCHs by the network entity. The network entity may determine the channel quality based on at least one L3-RSRP measurement. For each PDCCH from at least one different TRP in at least one PDCCH monitoring occasion, at least one PDCCH from the at least one TRP is delay counted. For example, the DAI may be determined based in part on at least one cumulative PDCCH number, where the actual index may be related to the count sequence. Thus, PDCCHs received from TRPs associated with lower channel qualities may be counted before TRPs associated with higher channel qualities. In some embodiments, the local count may be used for a first TRP having a lower channel quality and the global count may be used for a second TRP having a higher channel quality.

As shown in fig. 4, TRP2 may be a reference TRP based on a channel quality exceeding at least one predetermined threshold. In various embodiments, within the at least one PDCCH monitoring occasion, the at least one PDCCH from TRP2 may be counted after receiving the at least one PDCCH from TRP 1. For example, if a PDCCH of cDAI ═ 7 is absent, the UE may not know whether there is a PDCCH transmission that is actual because it is the last PDCCH. In response, when the PDCCH with cDAI-7 comes from a reference TRP for which the channel condition exceeds at least one predetermined threshold, this may reduce the probability that the PDCCH is missed below the at least one predetermined threshold.

In some embodiments, the NE may count at least one PDCCH. For example, at least one local index may be used for the DAI, wherein the TRP-specific separate PDCCH count is used for at least one other TRP, e.g., at least one TRP different from the reference TRP. Additionally or alternatively, the global index may be configured for DAI and have a joint PDCCH count for the reference TRP. As a result, this may provide a missed detection capability that exceeds at least one predetermined threshold configured to assist in referencing the DAI of the TRP. Further, when the UE does not receive the PDCCH of cDAI-6/3 but receives the PDCCHs of cDAI-5 and cDAI-7, the UE may be configured to know that the PDCCH of cDAI-6/3 is lost and there is no problem for determining the at least one HARQ-ACK codebook size.

In some embodiments, the at least one DAI indication bit may be determined based on at least one counter DAI having a modulo operation of 4 due to the 2-bit indication. In some embodiments, the NE may configure the UE with 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.

Referring to fig. 5, in the PDCCH monitoring machine, 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 of cDAI ═ 7 is absent, the UE may not know whether there is at least one actual PDCCH transmission because it is the last PDCCH. There may be a lower probability of at least one PDCCH being missed when the at least one PDCCH cDAI is from the TRP at 7 and the channel condition exceeds at least one predetermined threshold.

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 ability to cross-check between TRPs and detect missing PDCCH. Referring to fig. 5, when the UE does not receive at least one PDCCH of cDAI-6 but receives at least one PDCCH of cDAI-7, the UE may recognize that the PDCCH of 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 from the at least one cDAI based on a joint count of modulo 4.

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 including at least one DAI.

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

Fig. 8 illustrates an example of a method performed by a user device, such as user device 920 in fig. 9. 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, such as NE 910 in fig. 9. For example, a UE may receive multiple PDCCHs from different TRPs/CCs.

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 missed PDCCH, e.g., based on at least one DAI bit. In step 805, the UE may determine at least one HARQ-ACK codebook size. For example, the UE may directly set NACK for the ACK/NACK bit corresponding to the PDSCH scheduled by the missing PDCCH.

FIG. 9 illustrates an example of a system according to some example embodiments. In an example embodiment, a system may include multiple devices, such as, for example, network entity 910 and/or user equipment 920.

Network entity 910 may be one or more of the following: a base station (such as a millimeter wave antenna, evolved node b (enb) or 5G, or new radio node b (gnb)), a serving gateway, a server, and/or any other access node, or a combination thereof. Further, the network entity 910 and/or the user equipment 920 may be one or more of a citizen broadband radio service device (CBSD).

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.

One or more of these devices may include at least one processor, denoted 911 and 921, respectively. The

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 similar device. The processor may be implemented as a single controller or as multiple controllers or processors.

At least one memory may be provided in one or more of the devices indicated at 912 and 922. The memory may be fixed or removable. The memory may include computer program instructions or computer code embodied therein.

Memories

912 and 922 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A Hard Disk Drive (HDD), Random Access Memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor or may be separate from the processor or processors. Furthermore, the computer program instructions stored in the memory and processable by the processor may be computer program code in any suitable form, such as a compiled or interpreted computer program written in any suitable programming language. The memory may be removable or non-removable.

The

processors

911 and 921 and the

memories

912 and 922, or a subset thereof, may be configured to provide components corresponding to the various blocks of fig. 1-8. Although not shown, the device may also include positioning hardware, such as GPS or micro-electro-mechanical systems (MEMS) hardware, which may be used to determine the location of the device. Other sensors are also permitted and may be included to determine position, altitude, orientation, etc., such as barometers, compasses, etc.

As shown in fig. 9,

transceivers

913 and 923 can be provided, and one or more devices can also include at least one antenna, shown as 914 and 924, respectively. A device may have many antennas, such as an antenna array configured for multiple-input multiple-output (MIMO) communications, or multiple antennas for multiple radio access technologies. For example, other configurations of these devices may be provided. The

transceivers

913 and 923 can be transmitters, receivers, or both transmitters and receivers, or can be units or devices configured for both transmission and reception.

The memory and computer program instructions may be configured to, with the processor for a particular device, cause a hardware apparatus, such as a user equipment, to perform any of the processes described below (see, e.g., fig. 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, some example embodiments may be implemented entirely in hardware.

In some example embodiments, an apparatus may include circuitry configured to perform any of the processes or functions illustrated in fig. 1-8. For example, the circuitry may be a purely hardware circuit implementation, such as analog and/or digital circuitry. In another example, a circuit may be a combination of hardware circuitry and software, such as a combination of analog and/or digital hardware circuit(s) and software or firmware, and/or any portion of hardware processor(s) and software (including digital signal processor (s)), software, and at least one memory, that work together to cause an apparatus to perform various processes or functions. In yet another example, the circuitry may be hardware circuit(s) and/or processor(s), such as microprocessor(s) or a portion of microprocessor(s), including software, such as firmware for operation. Software in the circuit may not be present when the hardware operation does not require software.

The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, use of the phrases "some embodiments," "other embodiments," or other similar language throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. Thus, appearances of the phrases "in certain embodiments," "in some embodiments," "in other embodiments," or other similar language throughout this specification do not necessarily refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

One of ordinary skill in the art will readily appreciate that the invention as discussed above may be practiced with steps in a different order and/or with hardware elements in configurations other than those disclosed. Thus, while the invention has been described based upon these preferred embodiments, it would be apparent to those skilled in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the 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).

Part glossary

3GPP third generation partnership project

5G fifth generation wireless system

ACK acknowledgement

CA carrier aggregation

CC component carrier

Dynamic allocation of indices to cDAI counters

CORESET control resource set

DAI dynamically assigning indices

DCI dynamic control indicator

eMB enhanced mobile broadband

eNB evolved node B

E-UTRAN evolved universal mobile telecommunications system terrestrial radio access network

gNB next generation node B

HARQ hybrid automatic repeat request

LTE Long term evolution

MAC medium access control

MIMO multiple input multiple output

NACK negative acknowledgement

NCJT non-coherent joint transmission

NE network entity

NR new radio

PDCCH physical downlink control channel

PDSCH physical downlink shared channel

PUSCH physical uplink control channel

REL release

tDAI Total dynamic Allocation indexing

TRP transmission receiving point

UE user equipment

UL uplink

WI work item

Claims

1. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code,

wherein the at least one memory and the computer program code are configured to, 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 comprising at least one downlink allocation index, DAI; and

transmitting 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.

2. The apparatus of claim 1, wherein the at least one local DAI counting scheme is configured to count separately for each of a plurality of PDCCHs on a plurality of TRPs, and the at least one global DAI counting scheme is configured to count the plurality of PDCCHs on the plurality of TRPs as a single count.

3. The apparatus according to any of claim 1 and claim 2, wherein the at least one global DAI counting scheme takes into account channel quality between TRP and user equipment.

4. The apparatus according to any of claims 1-3, wherein the global 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.

5. The apparatus according to any of claims 1-4, wherein 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.

6. The apparatus according to any of claims 1-5, wherein one global PDCCH index is used in the DAI of the reference TRP to provide a checking capability for missing PDCCHs from other TRPs.

7. The apparatus of any of claims 1-6, wherein after the apparatus determines that the number of DAI bits is configured to 4 bits, or that CA is not configured, the apparatus further determines DAI using a modulo-4 operation based on a 3-dimensional count, the 3-dimensional count having the following order: the TRP is first followed by the component carrier, followed by the at least one PDCCH monitoring occasion index.

8. The apparatus according to any of claims 1-7, wherein after the apparatus determines that a 4-bit number of DAI bits is not configured or a 2-bit number of DAI bits is configured, the apparatus further determines DAI with a modulo-4 operation based on a global count having an order for configuration of the at least one PDCCH detection occasion from different TRPs.

9. The apparatus according to any of claims 1-8, 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.

10. The apparatus of any of claims 1-9, wherein after determining that CA is not configured, the apparatus further configures a number of bits 2 or 4 for DAI according to channel quality.

11. The apparatus of any of claims 1-10, wherein the apparatus further determines whether at least one Dynamic Allocation Index (DAI) bit number is configured.

12. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code,

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/or at least one global DAI counting scheme, wherein the received PDCCH comprises at least one downlink control information, DCI, field, which comprises at least one downlink allocation index, DAI;

detecting at least one PDCCH missing a detection; and

at least one hybrid automatic repeat request acknowledgement HARQ-ACK codebook size is determined.

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

14. The apparatus according to any of claims 12 and 13, wherein the at least one global DAI counting scheme takes into account channel quality between TRP and the user equipment.

15. The apparatus according to any of claims 12-14, wherein the global 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.

16. The apparatus according to any of claims 12-15, wherein the at least one reference TRP is associated with at least one channel quality exceeding at least one channel quality of at least one other TRP.

17. The apparatus according to any of claims 12-16, wherein one global PDCCH index is used in the DAI of the reference TRP to provide a checking capability for missing PDCCHs from other TRPs.

18. The method of any one of claims 1-17.

19. A non-transitory computer-readable medium encoding instructions that, when executed in hardware, perform the processes of any of claims 1-17.

20. An apparatus comprising means for performing a process according to any one of claims 1-17.

21. An apparatus comprising circuitry configured to cause the apparatus to perform the processes of any of claims 1-17.

22. A computer program product encoded with instructions for performing a process according to any of claims 1-17.