Patent Description:
The present disclosure relates to a cellular communications system and, in particular, activation and deactivation of transmission configuration indication states in a cellular communications system.

The new generation mobile wireless communication system (<NUM>) or New Radio (NR) supports a diverse set of use cases and a diverse set of deployment scenarios. NR uses Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) in the downlink (i.e. from a network node, gNB, eNB, or base station, to a user equipment or UE) and both CP-OFDM and Discrete Fourier Transform (DFT) -spread Orthogonal Frequency Division Multiplexing (OFDM) (DFT-S-OFDM) in the uplink (i.e. from UE to gNB). In the time domain, NR downlink and uplink physical resources are organized into equally-sized subframes of <NUM> millisecond (ms) each. A subframe is further divided into multiple slots of equal duration.

The slot length depends on subcarrier spacing. For subcarrier spacing of Δf = <NUM>, there is only one slot per subframe and each slot always consists of <NUM> OFDM symbols, irrespectively of the subcarrier spacing.

Typical data scheduling in NR are per slot basis. An example of the NR time-domain structure with <NUM> subcarrier spacing is shown in <FIG> where the first two symbols contain Physical Downlink Control Channel (PDCCH) and the remaining twelve symbols contains a Physical Data Channel (PDCH), which is either a Physical Downlink Shared Channel (PDSCH), which is a physical downlink data channel, or a Physical Uplink Shared Channel (PUSCH), which is a physical uplink data channel.

Different subcarrier spacing values are supported in NR. The supported subcarrier spacing values, which are also referred to as different numerologies, are given by Δf = (<NUM> × <NUM>α) kHz where α is a non-negative integer. Δf = <NUM>kHz is the basic subcarrier spacing that is also used in Long Term Evolution (LTE). The slot durations at different subcarrier spacings are shown in <FIG>.

In the frequency domain physical resource definition, a system bandwidth is divided into Resource Blocks (RBs), each corresponding to twelve contiguous subcarriers. The Common RBs (CRBs) are numbered starting with <NUM> from one end of the system bandwidth. The UE is configured with one or up to four Bandwidth Parts (BWPs) which may be a subset of the RBs supported on a carrier. Hence, a BWP may start at a CRB larger than zero. All configured BWPs have a common reference, which is CRB <NUM>. Hence, a UE can be configured with a narrow BWP (e.g. <NUM>) and a wide BWP (e.g. <NUM>), but only one BWP can be active for the UE at a given point in time. The Physical RBs (PRBs) are numbered from <NUM> to N-<NUM> within a BWP, but the <NUM>:th PRB may thus be the K:th CRB where K><NUM>.

The basic NR physical time-frequency resource grid is illustrated in <FIG>, where only one RB within a <NUM>-symbol slot is shown. One OFDM subcarrier during one OFDM symbol interval forms one Resource Element (RE).

Downlink transmissions can be dynamically scheduled, i.e., in each slot the gNB transmits Downlink Control Information (DCI) over Physical Downlink Control Channel (PDCCH) about which UE data is to be transmitted to and which RBs in the current downlink slot the data is transmitted on. PDCCH is typically transmitted in the first one or two OFDM symbols in each slot in NR. The UE data is carried on PDSCH. A UE first detects and decodes PDCCH and, if the decoding of PDCCH is successful, it then decodes the corresponding PDSCH based on the decoded control information in the PDCCH.

Uplink data transmission can also be dynamically scheduled using PDCCH. Similar to downlink, a UE first decodes uplink grants in PDCCH and then transmits data over PUSCH based the decoded control information in the uplink grant such as modulation order, coding rate, uplink resource allocation, etc..

Several signals can be transmitted from the same base station antenna from different antenna ports. These signals can have the same large-scale properties, for instance in terms of Doppler shift/spread, average delay spread, or average delay, when measured at the receiver. These antenna ports are then said to be quasi co-located (QCL).

The network can then signal to the UE that two antenna ports are QCL. If the UE knows that two antenna ports are QCL with respect to a certain parameter (e.g. Doppler spread), the UE can estimate that parameter based on a reference signal transmitted one of the antenna ports and use that estimate when receiving another reference signal or physical channel the other antenna port. Typically, the first antenna port is represented by a measurement reference signal such as Channel State Information Reference Signal (CSI-RS) (known as a source Reference Signal (RS)) and the second antenna port is a Demodulation Reference Signal (DMRS) (known as target RS) for PDSCH or PDCCH reception.

For instance, if antenna ports A and B are QCL with respect to average delay, the UE can estimate the average delay from the signal received from antenna port A (known as the source RS) and assume that the signal received from antenna port B (target RS) has the same average delay. This is useful for demodulation since the UE can know beforehand the properties of the channel when trying to measure the channel utilizing the DMRS, which may help the UE in for instance selecting an appropriate channel estimation filter.

Information about what assumptions can be made regarding QCL is signaled to the UE from the network. In NR, four types of QCL relations between a transmitted source RS and transmitted target RS were defined:.

QCL type D was introduced to facilitate beam management with analog beamforming and is known as spatial QCL. There is currently no strict definition of spatial QCL, but the understanding is that if two transmitted antenna ports are spatially QCL, the UE can use the same receive (Rx) beam to receive them. This is helpful for a UE that use analog beamforming to receive signals, since the UE needs to adjust its Rx beam in some direction prior to receiving a certain signal. If the UE knows that the signal is spatially QCL with some other signal it has received earlier, then it can safely use the same Rx beam to receive also this signal. Note that for beam management, the discussion mostly revolves around QCL Type D, but it is also necessary to convey a Type A QCL relation for the RSs to the UE, so that it can estimate all the relevant large-scale parameters.

Typically, this is achieved by configuring the UE with a CSI-RS for tracking (TRS) for time/frequency offset estimation. To be able to use any QCL reference, the UE would have to receive it with a sufficiently good Signal to Interference plus Noise Ratio (SINR). In many cases, this means that the TRS has to be transmitted in a suitable beam to a certain UE.

To introduce dynamics in beam and Transmission/Reception Point (TRP) selection, the UE can be configured through Radio Resource Control (RRC) signaling with MTCI states, where Mis up to <NUM> in frequency range <NUM> (FR2) for the purpose of PDSCH reception and up to <NUM> in frequency range <NUM> (FR1), depending on UE capability.

Each TCI state contains QCL information, i.e. one or two source downlink (DL) RSs, each source RS associated with a QCL type. For example, a TCI state contains a pair of reference signals, each associated with a QCL type, e-g- two different CSI-RSs {CSI-RS1, CSI-RS2} is configured in the TCI state as {qcl-Type1,qcl-Type2} = {Type A, Type D}. This means the UE can derive Doppler shift, Doppler spread, average delay, delay spread from CSI-RS1 and Spatial Rx parameter (i.e. the RX beam to use) from CSI-RS2.

Each of the M states in the list of TCI states can be interpreted as a list of M possible beams transmitted from the network or a list of M possible_TRPs used by the network to communicate with the UE. The M TCI states can also be interpreted as a combination of one or multiple beams transmitted from one or multiple TRPs.

A first list of available TCI states is configured for PDSCH, and a second list of TCI states is configured for PDCCH. Each TCI state contains a pointer, known as TCI State ID, which points to the TCI state. The network then activates, via Medium Access Control (MAC) Control Element (CE), one TCI state for PDCCH (i.e. provides a TCI for PDCCH) and up to eight TCI states for PDSCH. The number of active TCI states the UE supports is a UE capability, but the maximum is eight.

Each configured TCI state contains parameters for the quasi co-location associations between source reference signals (CSI-RS or Synchronization Signal (SS)/Physical Broadcast Channel (PBCH)) and target reference signals (e.g., PDSCH/PDCCH DMRS ports). TCI states are also used to convey QCL information for the reception of CSI-RS.

Assume a UE is configured with four active TCI states from a list of sixty-four (<NUM>) configured TCI states. Hence, sixty (<NUM>) TCI states are inactive for this particular UE (but some may be active for another UE) and the UE need not be prepared to have large scale parameters estimated for those. But the UE continuously tracks and updates the large-scale parameters for the four active TCI states by measurements and analysis of the source RSs indicated by each TCI state. When scheduling a PDSCH to a UE, the DCI contains a pointer to one active TCI. The UE then knows which large-scale parameter estimate to use when performing PDSCH DMRS channel estimation and thus PDSCH demodulation.

DMRS (also denoted herein as "DM-RS") are used for coherent demodulation of physical layer data channels, PDSCH (DL) and PUSCH (UL), as well as coherent demodulation of PDCCH. The DMRS is confined to resource blocks carrying the associated physical layer channel and is mapped on allocated resource elements of the OFDM time-frequency grid such that the receiver can efficiently handle time/frequency-selective fading radio channels.

The mapping of DMRS to resource elements is configurable in terms of density in both the frequency and time domains, with two mapping types in the frequency domain (configuration type <NUM> or type <NUM>) and two mapping types in the time domain (mapping type A or type B) defining the symbol position of the first DMRS within a transmission interval. The DMRS mapping in time domain can further be single-symbol based or double-symbol based where the latter means that DMRS is mapped in pairs of two adjacent symbols. Furthermore, a UE can be configured with one, two, three, or four single-symbol DMRS and one or two double-symbol DMRS. In scenarios with low Doppler, it may be sufficient to configure front-loaded DMRS only, i.e. one single-symbol DMRS or one double-symbol DMRS, whereas in scenarios with high Doppler additional DMRS will be required.

<FIG> shows the mapping of front-loaded DMRS for configuration type <NUM> and type <NUM> with single-symbol and double-symbol DMRS and for the mapping type A with first DMRS in third symbol of a transmission interval of <NUM> symbols. CDM groups are indicted by different hashing/fill patterns. We observe from this figure that type <NUM> and type <NUM> differs with respect to both the mapping structure and the number of supported DMRS CDM groups where type <NUM> support <NUM> CDM groups and Type <NUM> support <NUM> CDM groups.

In regard to Transmission Configuration Indicator (TCI) state activation/deactivation for UE-specific PDSCH via MAC CE, details of the MAC CE signaling that is used to activate/deactivate TCI states for UE specific PDSCH are provided. The structure of the MAC CE for activating/deactivating TCI states for UE specific PDSCH is given in <FIG>.

As shown in <FIG>, the MAC CE contains the following fields:.

Note that the TCI States Activation/Deactivation for UE-specific PDSCH MAC CE is identified by a MAC Protocol Data Unit (PDU) subheader with logical channel ID (LCID) as specified in Table <NUM>. <NUM>-<NUM> of 3GPP TS <NUM> (this table is reproduced below in Table <NUM>). The MAC CE for Activation/Deactivation of TCI States for UE-specific PDSCH has variable size.

Non-coherent Joint Transmission (NC-JT) refers to Multiple Input Multiple Output (MIMO) data transmission over multiple TRPs or panels in which different MIMO layers are transmitted over different TRPs. Two ways of scheduling NC-JT multi-TRP transmission are specified in NR Rel-<NUM>: multi-PDCCH based multi-TRP transmission and single-PDCCH based multi-TRP transmission.

In regard to multi-PDCCH based multi-TRP transmission, an example is shown in <FIG>, where data is sent to a UE over two TRPs, each TRP carrying one Transport Block (TB) mapped to one code word. When the UE has four receive antennas while each of the TRPs has only two transmit antennas, the UE can support up to four MIMO layers but each TRP can maximally transmit two MIMO layers. In this case, by transmitting data over two TRPs to the UE, the peak data rate to the UE can be increased as up to four aggregated layers from the two TRPs can be used. This is beneficial when the traffic load, and thus the resource utilization, is low in each TRP. In this example, a single scheduler is used to schedule data over the two TRPs. One PDCCH is transmitted from each of the two TRPs in a slot, each schedule one PDSCH. This is referred to as a multi-PDCCH or multi-DCI scheme in which a UE receives two PDCCHs and the associated two PDSCHs in a slot from two TRPs.

In another scenario shown in <FIG>, independent schedulers are used in each TRP. In this case, only semi-static to semi-dynamic coordination between the two schedulers can be done due the non-ideal backhaul, i.e., backhaul with large delay and/or delay variations which are comparable to the cyclic prefix length or in some cases even longer, up to several milliseconds.

In NR specification 3GPP TS <NUM>, there is a restriction stating:
The UE may assume that the PDSCH DM-RS within the same CDM group are quasi co-located with respect to Doppler shift, Doppler spread, average delay, delay spread, and spatial Rx.

In cases where a UE is not scheduled all DMRS ports within a CDM group, there may be another UE simultaneously scheduled using the remaining ports of that CDM group. The UE can then estimate the channel for that other UE (thus an interfering signal) in order to perform coherent interference suppression. Hence, this is useful in Multi-User MIMO (MU-MIMO) scheduling and UE interference suppression.

In case of a multi-TRP scenario in which the UE receives PDSCHs via multiple PDCCHs transmitted from different TRPs, the signals transmitted from different TRPs will most likely not be quasi-collocated, as the TRPs may be spatially separated. In this case, the PDSCHs transmitted from different TRPs will have different TCI states associated with them. Furthermore, according to the above restriction, two PDSCH DMRSs associated with two TRPs will have to belong to different DMRS CDM groups (as the two PDSCH DMRSs are not QCL, they cannot belong to the same DMRS CDM group). <FIG> illustrates an example relationship between TCI states and DMRS CDM groups for a multiple-PDCCH multi-TRP scenario. In the example, PDSCH1 is associated with TCI State p, and PDSCH <NUM> is associated with TCI state q. The PDSCH DMRSs from the different TRPs also belong to different DMRS CDM groups as they are not quasi-collocated. In the example, the DMRS for PDSCH1 belongs to CDM group u while the DMRS for PDSCH2 belongs to CDM group v.

In RAN1#<NUM>, the following agreement was made:.

To support multiple-PDCCH based multi-TRP/panel transmission with intra-cell (same cell ID) and inter-cell (different Cell IDs), following RRC configuration can be used to link multiple PDCCH/PDSCH pairs with multiple TRPs.

According to the above underlined part in the agreement, a CORESET is used to differentiate between TRPs. That is, one CORESET corresponds to one of the TRPs and another CORESET corresponds to the second TRP. Note that there is one 'PDCCH-config' per dedicated downlink BWP. In RAN1#<NUM>, the following was further agreed:.

For multi-PDCCH based multi-TRP operation, increase the maximum number of CORESETs per "PDCCH-config" to <NUM>, according to UE capability.

According to the above underlined and italicized part in the agreement, the number of CORESETs per 'PDCCH-config' was increased to five from three (note that three is the limit for NR Rel-<NUM>) in order to flexibly assign <NUM>-<NUM> CORESETs per TRP. Furthermore, in RAN1#<NUM>, it was agreed to introduce a higher layer index per CORSET in order to pool or group the CORESETs. The CORESETs with the same higher layer index value belongs to the same CORESET pool and corresponds to one TRP.

Hence, in NR Rel-<NUM>, for multi-TRP PDSCH transmission with multiple PDCCHs, one or multiple CORESET pools (configured via a higher layer index per CORESET) may be configured for a UE. A CORESET pool consists of one or more CORESETs.

For single-PDCCH based multi-TRP transmission, the single PDCCH is received from one of the TRPs while PDSCH(s) will be received from both TRPs. <FIG> shows an example where a DCI received by the UE in PDCCH from TRP1 schedules two PDSCHs. The first PDSCH (PDSCH1) is received from TRP1, and the second PDSCH (PDSCH2) is received from TRP2. Even though <FIG> shows two PDSCHs being scheduled by a single-PDCCH, the single PDCCH scheme is also applicable for the case where different PDSCH layer sets belonging to the same PDSCH are received from the two TRPs. This is illustrated in the example of <FIG>, where PDSCH layer set <NUM> is received from TRP1, and PDSCH layer set <NUM> is received from TRP2.

In such cases, each PDSCH or PDSCH layer set transmitted from a different TRP has a different TCI state associated with it. In the examples of <FIG>, PDSCH1 and PDSCH layer set <NUM> are associated with TCI State p, and PDSCH2 and PDSCH layer set <NUM> are associated with TCI state q. The PDSCH DMRSs from the different TRPs may belong to different DMRS CDM groups. In the example of <FIG>, the DMRS for PDSCH1 belongs to CDM group u while the DMRS for PDSCH2 belongs to CDM group v.

In the RAN1 AdHoc meeting in January <NUM>, the following is agreed:.

TCI indication framework shall be enhanced in Rel-<NUM> at least for eMBB:.

According to the above agreement, each codepoint in the DCI Transmission Configuration Indication field can be mapped to either one or two TCI states. This can be interpreted as follows: A DCI in PDCCH schedules one or two PDSCHs or PDSCH layer sets with each PDSCH or PDSCH layer set associated with a different TCI state; the codepoint of the Transmission Configuration Indication field in DCI indicates the <NUM>-<NUM> TCI states associated with the one or two PDSCHs scheduled. Additionally, according to the above agreement, at least for DMRS type <NUM>, PDSCH DMRS associated with one TCI state is contained within one DMRS CDM group.

There currently exist certain challenge(s). As discussed above, in the NR Rel-<NUM> MAC CE for TCI States Activation/Deactivation for UE-specific PDSCH, a single codepoint of the DCI Transmission Configuration Indication field can only be mapped to a single TCI State. Hence, the NR Rel-<NUM> MAC CE for TCI States Activation/Deactivation for UE-specific PDSCH cannot be used for single-PDCCH based multi-TRP where one codepoint in the DCI Transmission Configuration Indication field needs to be mapped to either one or two TCI states. Furthermore, in NR Rel-<NUM>, the MAC CE for TCI states Activation/Deactivation for UE-specific PDSCH should also support multi-PDCCH based multi-TRP transmission. Hence, it is an open problem how to use MAC CE for TCI state activation for PDSCH considering both single-PDCCH based multi-PDSCH scheduling and multiple-PDCCH based multi-PDSCH scheduling needs to be supported.

Document "<NPL>on. Inter alia, the following proposals were made. Proposal <NUM>: For NCJT transmission which is based on single PDCCH, at least support entries listed in Table <NUM>-<NUM> in the case when dmrs-Type=<NUM>, maxLength=<NUM> and support entries listed in Table <NUM>-<NUM> in the case when dmrs-Type=<NUM>, maxLength=<NUM>: port <NUM> (for 1st TCI), <NUM>, <NUM> (for 2nd TCI) are supported for <NUM>+<NUM> layers. Proposal <NUM>: When two TCI states are indicated by TCI codepoint in DCI, a new DMRS table is used. When single TCI state is indicated by TCI codepoint in DCI, the Rel-<NUM> DMRS table is used. In the new table: DMRS ports corresponding to two CDM groups indicated by each entry are mapped to two TCI states respectively. The mapping between CDM group and TCI state can be different in different entries. Proposal <NUM>: Support two DL PTRS ports: the maximum number of PTRS ports should be the same as the number of indicated TCI states. Proposal <NUM>: For single PDCCH design, if the offset between the reception of the DL DCI and the corresponding PDSCH is less than the threshold timeDurationForQCL, the default QCL assumption of PDSCH should be enhanced: support two default TCI states which are used for the two DMRS groups of PDSCH respectively if the offset between the DL DCI and the PDSCH is less than the threshold. Proposal <NUM>: The maximum number of MAC-CE activated TCI states should be increased to <NUM>. Proposal <NUM>: For scheme <NUM>, the number of intra-slot repetitions is the same as the number of DCI indicated TCI states. Proposal <NUM>: For scheme <NUM> and <NUM>: the first half PDSCH repetitions are associated with the first TCI state in DCI-indicated TCI codepoint, and the second half PDSCH repetitions are associated with the second TCI state in DCI-indicated TCI codepoint; and support Rel-<NUM> RV sequences for PDSCH repetitions with the same TCI state, predefine the RV relationship between the first PDSCH repetitions of two TRP, RV codepoint is to indicate the RV value of the first PDSCH repetition which is associated with the first TCI state. Proposal <NUM>: Support dynamic switching among single TRP, scheme 1a, 2a, 2b and <NUM>: if one TCI state is indicated by TCI codepoint, it is single TRP transmission and Rel-<NUM> DMRS table is used; and if two TCI states are indicated by TCI codepoint, it is multi-TRP/panel transmission and a new DMRS table is used, different entry sets in the new DMRS table can represent scheme 1a, 2a, 2b and <NUM>.

Document 3GPP TS <NUM> V15. <NUM> relates to the NR MAC protocol. The TCI States Activation/Deactivation for UE-specific PDSCH MAC CE is identified by a MAC PDU subheader with LCID. It has a variable size comprising the fields: serving Cell ID, this field indicates the identity of the Serving Cell for which the MAC CE applies, and the length of the field is <NUM> bits; and BWP ID, this field contains BWP-Id of a downlink bandwidth part for which the MAC CE applies, and the length of the BWP ID field is <NUM> bits.

Document 3GPP TS <NUM> V15. <NUM> relates to characteristics of the physicals layer procedures of data channels for <NUM>-NR. The UE can be configured with a list of up to M TCI-State configurations within the higher layer parameter PDSCH-Config to decode PDSCH according to a detected PDCCH with DCI intended for the UE and the given serving cell, where M depends on the UE capability. Each TCI-State contains parameters for configuring a quasi co-location relationship between one or two downlink reference signals and the DM-RS ports of the PDSCH. The quasi co-location relationship is configured by the higher layer parameter qcl-Type1 for the first DL RS, and qcl-Type2 for the second DL RS (if configured).

Document "<NPL>, discloses a single MAC-CE to activate the same set of TCI states for multiple CCs. Further, when a set of TCI-state IDs for PDSCH are activated by a MAC CE for a set of CCs/BWPs at least for the same band, where the applicable list of CCs is indicated by RRC signalling, the same set of TCI-state IDs are applied for the all BWPs in the indicated CCs. Regarding questions on single PDCCH multi-TRP based operation, it is disclosed that each TCI codepoint can correspond to <NUM> or <NUM> TCI states.

Document <CIT> constitutes prior art under Article <NUM>(<NUM>) EPC and discloses a technique in which, in a wireless communication system, a user equipment (UE) transmits, to a base station (BS), UE capability information comprising whether the UE supports cooperative communication for receiving physical downlink shared channels (PDSCHs) from a plurality of transmission reception points (TRPs) in a particular time-frequency resource, obtains, via radio resource control (RRC), information about whether the cooperative communication is to be applied from the BS, identifies a format of a medium access control (MAC) control element (CE) received from the BS based on whether the BS is to apply the cooperative communication, and determines transmission configuration indication (TCI) states according to the respective TRPs, based on the identified format of the MAC CE.

Systems and methods are disclosed herein for updating an active Transmission Configuration Indication (TCI) state for single Physical Downlink Control Channel (PDCCH) based or multi-PDCCH based multi-Transmission/Reception Point (TRP) Physical Downlink Shared Channel (PDSCH) transmissions.

According to the present disclosure, methods, computer-readable media, a wireless communication device and a network node according to the independent claims are provided. Developments are set forth in the dependent claims.

In one embodiment, a method performed by a wireless communication device in a cellular communications system comprises receiving, from a network node, a Medium Access Control (MAC) Control Element (CE) for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a particular serving cell and/or bandwidth part (BWP) of the wireless communication device where the particular serving cell and/or BWP is configured for multi-PDCCH based multi-PDSCH transmission and maps at most one of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a Downlink Control information (DCI) transmission configuration indication field. The method further comprises receiving a PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field and determining a TCI state from among the one or more TCI states activated by the MAC CE used for a PDSCH scheduled by the DCI based on the information comprised in the DCI that maps at most one of the one or more TCI states activated by the MAC CE to each of the plurality of codepoints for the DCI transmission configuration indication field. In this manner, a unified MAC CE design is provided for both single-PDCCH based scheduling and multi-PDCCH based scheduling.

In one embodiment, the PDSCH scheduled by the DCI is part of a multi-PDCCH based multi-PDSCH transmission.

In one embodiment, the method further comprises receiving the PDSCH scheduled by the DCI.

Corresponding embodiments of a wireless communication device are also disclosed. In one embodiment, a wireless communication device for a cellular communications system is adapted to receive, from a network node, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a particular serving cell and/or BWP of the wireless communication device where the particular serving cell and/or BWP is configured for multi-PDCCH based multi-PDSCH transmission and maps at most one of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field. The wireless communication device is further adapted to receive a PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field and determine a TCI state from among the one or more TCI states activated by the MAC CE used for a PDSCH scheduled by the DCI based on the information comprised in the DCI that maps at most one of the one or more TCI states activated by the MAC CE to each of the plurality of codepoints for the DCI transmission configuration indication field.

In one embodiment, a wireless communication device for a cellular communications system comprises one or more transmitters, one or more receivers, and processing circuitry associated with the one or more transmitters and the one or more receivers. The processing circuitry is configured to cause the wireless communication device to receive, from a network node, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a particular serving cell and/or BWP of the wireless communication device where the particular serving cell and/or BWP is configured for multi-PDCCH based multi-PDSCH transmission and maps at most one of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field. The processing circuitry is further configured to cause the wireless communication device to receive a PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field and determine a TCI state from among the one or more TCI states activated by the MAC CE used for a PDSCH scheduled by the DCI based on the information comprised in the DCI that maps at most one of the one or more TCI states activated by the MAC CE to each of the plurality of codepoints for the DCI transmission configuration indication field.

Embodiments of a method performed by a network node are also disclosed. In one embodiment, a method performed by a network node in a cellular communications system comprises transmitting or initiating transmission of, to a wireless communication device, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a particular serving cell and/or BWP of the wireless communication device where the particular serving cell is configured for multi-PDCCH based multi-PDSCH transmission and maps at most one of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field. The method further comprises transmitting or initiating transmission of a PDCCH to the wireless communication device, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field that is mapped to a desired TCI state for a PDSCH scheduled by the DCI.

In one embodiment, the method further comprises transmitting or initiating transmission of the PDSCH scheduled by the DCI.

Corresponding embodiments of a network node are also disclosed. In one embodiment, a network node for a cellular communications system is adapted to transmit or initiate transmission of, to a wireless communication device, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a particular serving cell and/or BWP of the wireless communication device where the particular serving cell and/or BWP is configured for multi-PDCCH based multi-PDSCH transmission and maps at most one of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field. The network node is further adapted to transmit or initiate transmission of a PDCCH to the wireless communication device, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field that is mapped to a desired TCI state for a PDSCH scheduled by the DCI.

In one embodiment, a network node for a cellular communications system comprises processing circuitry configured to cause the network node to transmit or initiate transmission of, to a wireless communication device, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a particular serving cell and/or BWP of the wireless communication device where the particular serving cell and/or BWP is configured for multi-PDCCH based multi-PDSCH transmission and maps at most one of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field. The processing circuitry is further configured to cause the network node to transmit or initiate transmission of a PDCCH to the wireless communication device, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field that is mapped to a desired TCI state for a PDSCH scheduled by the DCI.

In another embodiment, a method performed by a wireless communication device in a cellular communications system comprises receiving, from a network node, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a plurality of component carriers (CCs) comprised in a configured list of CCs for which simultaneous TCI state updates are enabled and maps at most X of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field, where X is an integer greater than or equal to <NUM>. The configured list of CCs only comprises CCs that have either multi-PDCCH based multi-PDSCH transmission enabled or single-PDCCH based single-PDSCH or multi-PDSCH transmission enabled.

In one embodiment, X=<NUM>. In another embodiment, X=<NUM>.

In one embodiment, the method further comprises receiving a PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field, the PDCCH being a PDCCH for either a multi-PDCCH based multi-PDSCH transmission or a single-PDCCH based single-PDSCH or multi-PDSCH transmission on one or more of the plurality of CCs comprised in the configured list of CCs. The method further comprises determining at least one TCI state from among the one or more TCI states activated by the MAC CE used for at least one PDSCH scheduled by the DCI based on the information comprised in the DCI that maps at most one of the one or more TCI states activated by the MAC CE to each of the plurality of codepoints for the DCI transmission configuration indication field. In one embodiment, the at least one PDSCH scheduled by the DCI is part of a multi-PDCCH based multi-PDSCH transmission. In one embodiment, the method further comprises receiving the at least one PDSCH scheduled by the DCI.

In one embodiment, the method further comprises receiving, from a network node, the configured list of CCs for which simultaneous TCI state updates are enabled.

Corresponding embodiments of a wireless communication device are also disclosed. In one embodiment, a wireless communication device for a cellular communications system is adapted to receive, from a network node, a MAC CE for TCI state activation or deactivation. The MAC CE comprising information that activates one or more TCI states for a plurality of CCs comprised in a configured list of CCs for which simultaneous TCI state updates are enabled and maps at most X of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field, where X is an integer greater than or equal to <NUM>. The configured list of CCs only comprises CCs that have either multi-PDCCH based multi-PDSCH transmission enabled or single-PDCCH based single-PDSCH or multi-PDSCH transmission enabled.

In one embodiment, a wireless communication device for a cellular communications system comprises one or more transmitters, one or more receivers, and processing circuitry associated with the one or more transmitters and the one or more receivers. The processing circuitry is configured to cause the wireless communication device to receive, from a network node, a MAC CE for TCI state activation or deactivation. The MAC CE comprising information that activates one or more TCI states for a plurality of CCs comprised in a configured list of CCs for which simultaneous TCI state updates are enabled and maps at most X of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field, where X is an integer greater than or equal to <NUM>. The configured list of CCs only comprises CCs that have either multi-PDCCH based multi-PDSCH transmission enabled or single-PDCCH based single-PDSCH or multi-PDSCH transmission enabled.

In another embodiment, a method performed by a network node in a cellular communications system comprises transmitting or initiating transmission of, to a wireless communication device a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a plurality of CCs comprised in a configured list of CCs for which simultaneous TCI state updates are enabled and maps at most X of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field, where X is an integer greater than or equal to <NUM>. The configured list of CCs only comprises CCs that have either multi-PDCCH based multi-PDSCH transmission enabled or single-PDCCH based single-PDSCH or multi-PDSCH transmission enabled.

In one embodiment, the method further comprises transmitting or initiating transmission of a PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field. The PDCCH is a PDCCH for either a multi-PDCCH based multi-PDSCH transmission or a single-PDCCH based single-PDSCH or multi-PDSCH transmission on one or more of the plurality of CCs comprised in the configured list of CCs. The particular codepoint is mapped to at least one TCI state from among the one or more TCI states activated by the MAC CE used for at least one PDSCH scheduled by the DCI. In one embodiment, the at least one PDSCH scheduled by the DCI is part of a multi-PDCCH based multi-PDSCH transmission. In one embodiment, the method further comprises transmitting or initiating transmission of the at least one PDSCH scheduled by the DCI.

In one embodiment, the method further comprises transmitting or initiating transmission of, to the wireless communication device, the configured list of CCs for which simultaneous TCI state updates are enabled.

Corresponding embodiments of a network node are also disclosed. In one embodiment, a network node for a cellular communications system is adapted to transmit or initiate transmission of, to a wireless communication device, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a plurality of CCs comprised in a configured list of CCs for which simultaneous TCI state updates are enabled and maps at most X of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field, where X is an integer greater than or equal to <NUM>. The configured list of CCs only comprises CCs that have either multi-PDCCH based multi-PDSCH transmission enabled or single-PDCCH based single-PDSCH or multi-PDSCH transmission enabled.

In one embodiment, a network node for a cellular communications system comprises processing circuitry configured to cause the network node to transmit or initiate transmission of, to a wireless communication device, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states for a plurality of CCs comprised in a configured list of CCs for which simultaneous TCI state updates are enabled and maps at most X of the one or more TCI states activated by the MAC CE to each of a plurality of codepoints for a DCI transmission configuration indication field, where X is an integer greater than or equal to <NUM>. The configured list of CCs only comprises CCs that have either multi-PDCCH based multi-PDSCH transmission enabled or single-PDCCH based single-PDSCH or multi-PDSCH transmission enabled.

In another embodiment, a method performed by a wireless communication device in a cellular communications system comprises receiving, from a network node, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states and defines a codepoint to TCI state mapping, wherein the codepoint to TCI state mapping maps each of a plurality of codepoints for a DCI transmission configuration indication field to at most X of the one or more TCI states activated by the MAC CE, where X is an integer greater than or equal to <NUM>. The MAC CE further comprises a control resource set (CORESET) pool identity (ID) that indicates that the one or more TCI states activated by the MAC CE and the codepoint to TCI state mapping defined by the information comprised in the MAC CE are to be applied to a PDCCH that is carried within any CORESET in a CORESET pool indicated by the CORESET pool ID. The method further comprises receiving a PDCCH carried within a CORESET in the CORESET pool indicated by the CORESET pool ID, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field. The method further comprises determining a TCI state from among the one or more TCI states activated by the MAC CE used for a PDSCH scheduled by the DCI based on the information comprised in the DCI.

Corresponding embodiments of a wireless communication device are also disclosed. In one embodiment, a wireless communication device for a cellular communications system is adapted to receive, from a network node, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states and defines a codepoint to TCI state mapping, wherein the codepoint to TCI state mapping maps each of a plurality of codepoints for a DCI transmission configuration indication field to at most X of the one or more TCI states activated by the MAC CE, where X is an integer greater than or equal to <NUM>. The MAC CE further comprises a CORESET pool ID that indicates that the one or more TCI states activated by the MAC CE and the codepoint to TCI state mapping defined by the information comprised in the MAC CE are to be applied to a PDCCH that is carried within any CORESET in a CORESET pool indicated by the CORESET pool ID. The wireless communication device is further adapted to receive a PDCCH carried within a CORESET in the CORESET pool indicated by the CORESET pool ID, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field. The wireless communication device is further adapted to determine a TCI state from among the one or more TCI states activated by the MAC CE used for a PDSCH scheduled by the DCI based on the information comprised in the DCI.

In one embodiment, a wireless communication device for a cellular communications system comprises one or more transmitters, one or more receivers, and processing circuitry associated with the one or more transmitters and the one or more receivers. The processing circuitry is configured to cause the wireless communication device to receive, from a network node, a MAC CE for TCI state activation or deactivation. The MAC CE comprises information that activates one or more TCI states and defines a codepoint to TCI state mapping, wherein the codepoint to TCI state mapping maps each of a plurality of codepoints for a DCI transmission configuration indication field to at most X of the one or more TCI states activated by the MAC CE, where X is an integer greater than or equal to <NUM>. The MAC CE further comprises a CORESET pool ID that indicates that the one or more TCI states activated by the MAC CE and the codepoint to TCI state mapping defined by the information comprised in the MAC CE are to be applied to a PDCCH that is carried within any CORESET in a CORESET pool indicated by the CORESET pool ID. The processing circuitry is further configured to cause the wireless communication device to receive a PDCCH carried within a CORESET in the CORESET pool indicated by the CORESET pool ID, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field. The processing circuitry is further configured to cause the wireless communication device to determine a TCI state from among the one or more TCI states activated by the MAC CE used for a PDSCH scheduled by the DCI based on the information comprised in the DCI.

In another embodiment, a method performed by a network node in a cellular communications system comprises transmitting or initiating transmission of a MAC CE for TCI state activation or deactivation to a wireless communication device. The MAC CE comprises information that activates one or more TCI states and defines a codepoint to TCI state mapping, wherein the codepoint to TCI state mapping maps each of a plurality of codepoints for a DCI transmission configuration indication field to at most X of the one or more TCI states activated by the MAC CE, where X is an integer greater than or equal to <NUM>. The MAC CE further comprises a CORESET pool ID that indicates that the one or more TCI states activated by the MAC CE and the codepoint to TCI state mapping defined by the information comprised in the MAC CE are to be applied to a PDCCH that is carried within any CORESET in a CORESET pool indicated by the CORESET pool ID. The method further comprises transmitting or initiating transmission of a PDCCH carried within a CORESET in the CORESET pool indicated by the CORESET pool ID to the wireless communication device, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field.

Corresponding embodiments of a network node are also disclosed. In one embodiment, a network node for a cellular communications system is adapted to transmit or initiate transmission of a MAC CE for TCI state activation or deactivation to a wireless communication device. The MAC CE comprises information that activates one or more TCI states and defines a codepoint to TCI state mapping, wherein the codepoint to TCI state mapping maps each of a plurality of codepoints for a DCI transmission configuration indication field to at most X of the one or more TCI states activated by the MAC CE, where X is an integer greater than or equal to <NUM>. The MAC CE further comprises a CORESET pool ID that indicates that the one or more TCI states activated by the MAC CE and the codepoint to TCI state mapping defined by the information comprised in the MAC CE are to be applied to a PDCCH that is carried within any CORESET in a CORESET pool indicated by the CORESET pool ID. The network node is further adapted to transmit or initiate transmission of a PDCCH carried within a CORESET in the CORESET pool indicated by the CORESET pool ID to the wireless communication device, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field.

In one embodiment, a network node for a cellular communications system comprises processing circuitry configured to cause the network node to transmit or initiate transmission of a MAC CE for TCI state activation or deactivation to a wireless communication device. The MAC CE comprises information that activates one or more TCI states and defines a codepoint to TCI state mapping, wherein the codepoint to TCI state mapping maps each of a plurality of codepoints for a DCI transmission configuration indication field to at most X of the one or more TCI states activated by the MAC CE, where X is an integer greater than or equal to <NUM>. The MAC CE further comprises a CORESET pool ID that indicates that the one or more TCI states activated by the MAC CE and the codepoint to TCI state mapping defined by the information comprised in the MAC CE are to be applied to a PDCCH that is carried within any CORESET in a CORESET pool indicated by the CORESET pool ID. The processing circuitry is further configured to cause the network node to transmit or initiate transmission of a PDCCH carried within a CORESET in the CORESET pool indicated by the CORESET pool ID to the wireless communication device, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field.

Core Network Node: As used herein, a "core network node" is any type of node in a core network or any node that implements a core network function. Some examples of a core network node include, e.g., a Mobility Management Entity (MME), a Packet Data Network Gateway (P-GW), a Service Capability Exposure Function (SCEF), a Home Subscriber Server (HSS), or the like. Some other examples of a core network node include a node implementing a Access and Mobility Function (AMF), a UPF, a Session Management Function (SMF), an Authentication Server Function (AUSF), a Network Slice Selection Function (NSSF), a Network Exposure Function (NEF), a Network Function (NF) Repository Function (NRF), a Policy Control Function (PCF), a Unified Data Management (UDM), or the like.

Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. In some embodiments (e.g., the set of embodiments referred to below as "Embodiment <NUM>"), solutions are proposed on how to map Transmission Configuration Indicator (TCI) states to codepoints in the TCI field (e.g., maximum number of TCI states to be mapped to codepoints in TCI field) in Downlink Control Information (DCI) depending on whether the serving cell or Bandwidth Part (BWP) indicated in the Medium Access Control (MAC) Control Element (CE) is configured for multi-Physical Downlink Control Channel (PDCCH) based multi-Physical Downlink Shared Channel (PDSCH) reception or single-PDCCH based single PDSCH reception.

In some embodiments (e.g., the set of embodiments referred to below as "Embodiment <NUM>"), solutions are proposed on how to efficiently map TCI states to codepoints in the TCI field for a plurality of serving cells or BWPs depending on whether at least one of the plurality of serving cells or bandwidth parts indicated in the MAC CE is configured for multi-PDCCH based multi-PDSCH reception or single-PDCCH based single PDSCH reception.

In some embodiments (e.g., the set of embodiments referred to below as "Embodiment <NUM>"), solutions are proposed on how to simultaneously update TCI states for PDSCH for multiple TRPs by indicating the Control Resource Set (CORESET) pool index associated with each TRP within the MAC CE along with the corresponding TCI states to be activated.

Certain embodiments may provide one or more of the following technical advantage(s). Embodiments of the proposed solutions may provide a unified MAC CE design for both single-PDCCH based multi-PDSCH scheduling and multiple-PDCCH based multi-PDSCH scheduling which are both supported in NR Rel-<NUM>. A key benefit of this is that it makes multi-PDCCH based multi-TRP transmission suitable for DMRS type <NUM> which is the mandatory DMRS configuration in NR. Embodiments <NUM> and <NUM> provide efficient MAC CE signaling with reduced overhead since these embodiments allow TCI states to be simultaneously updated for multiple cells or multiple TRPs.

<FIG> illustrates one example of a cellular communications system <NUM> in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system <NUM> is a <NUM> system (5GS) including a NR RAN or LTE RAN (i.e., E-UTRA RAN). In this example, the RAN includes base stations <NUM>-<NUM> and <NUM>-<NUM>, which in <NUM> NR are referred to as gNBs and in <NUM> with LTE RAN nodes connected to the 5GC are referred to as ng-eNBs, controlling corresponding (macro) cells <NUM>-<NUM> and <NUM>-<NUM>. The base stations <NUM>-<NUM> and <NUM>-<NUM> are generally referred to herein collectively as base stations <NUM> and individually as base station <NUM>. Likewise, the (macro) cells <NUM>-<NUM> and <NUM>-<NUM> are generally referred to herein collectively as (macro) cells <NUM> and individually as (macro) cell <NUM>. The RAN may also include a number of low power nodes <NUM>-<NUM> through <NUM>-<NUM> controlling corresponding small cells <NUM>-<NUM> through <NUM>-<NUM>. The low power nodes <NUM>-<NUM> through <NUM>-<NUM> can be small base stations (such as pico or femto base stations) or Remote Radio Heads (RRHs), or the like. Notably, while not illustrated, one or more of the small cells <NUM>-<NUM> through <NUM>-<NUM> may alternatively be provided by the base stations <NUM>. The low power nodes <NUM>-<NUM> through <NUM>-<NUM> are generally referred to herein collectively as low power nodes <NUM> and individually as low power node <NUM>. Likewise, the small cells <NUM>-<NUM> through <NUM>-<NUM> are generally referred to herein collectively as small cells <NUM> and individually as small cell <NUM>. The cellular communications system <NUM> also includes a core network <NUM>, which in the 5GS is referred to as the <NUM> core (5GC). The base stations <NUM> (and optionally the low power nodes <NUM>) are connected to the core network <NUM>.

In the following description, the wireless communication devices <NUM> are oftentimes UEs and as such are sometimes referred to herein as UEs <NUM>, but the present disclosure is not limited thereto.

Now, a description of some example embodiments of the present disclosure will be described. While described under separate headings, these embodiments may be used separately or in any desired combination.

In some embodiments (e.g., the set of embodiments referred to below as "Embodiment <NUM>"), solutions are proposed on how to map TCI states to codepoints in the TCI field (e.g., maximum number of TCI states to be mapped to codepoints in TCI field) in DCI depending on whether the serving cell or bandwidth part indicated in the MAC CE is configured for multi-PDCCH based multi-PDSCH reception or single-PDCCH based single PDSCH reception.

In some embodiments (e.g., the set of embodiments referred to below as "Embodiment <NUM>"), solutions are proposed on how to simultaneously update TCI states for PDSCH for multiple TRPs by indicating the CORESET pool index associated with each TRP within the MAC CE along with the corresponding TCI states to be activated.

In this embodiment, if a given serving cell with identity given by 'Serving Cell ID' indicated in the MAC CE activating/deactivating TCI states for PDSCH for this serving cell is configured for multi-PDCCH based PDSCH reception, then the UE <NUM> receives a mapping with at most one TCI state mapped (i.e., indicated) for each of the codepoints in the DCI Transmission Configuration Indication field.

It should be noted that more than one TCI state mapped per codepoint in the DCI Transmission Configuration Indication field is only needed in case of single PDCCH scheduling multiple PDSCHs or multiple PDSCH layer sets. For multiple PDCCHs scheduling multiple PDSCHs (e.g., two PDCCHs scheduling two PDSCHs), one TCI state mapped per codepoint in the DCI Transmission Configuration Indication field is sufficient as there are multiple DCIs, and each DCI will indicate one TCI state using a codepoint in the Transmission Configuration Indication field.

With DMRS type <NUM>, there are only two CDM groups and multiple PDCCHs scheduling two PDSCHs from two TRPs will need two CDM groups, particularly when these two PDSCHs are fully overlapping or partially overlapping in time frequency domain. <FIG> shows an example of multi-PDCCH scheduling two different PDSCHs which are fully overlapping in time-frequency domain, in which case DMRS CDM groups <NUM> and <NUM> are used for PDSCHs <NUM> and <NUM> respectively.

<FIG> shows another example of a multi-PDCCH scheduling where PDCCH1 schedules a single PDSCH (i.e., PDSCH <NUM>) while PDCCH2 schedules two different PDSCHs (i.e., PDSCH <NUM> and PDSCH <NUM>). In this example, PDCCH2 is a single PDCCH scheduling two PDSCHs from two TRPs (TRPs <NUM> and <NUM>). Since TRPs <NUM> and <NUM> are spatially separated, different CDM groups need to be indicated for PDSCHs <NUM> and <NUM>. Hence, in the case of PDCCH2, two TCI states need to be mapped per codepoint in the DCI Transmission Configuration Indication field. However, this example requires a total of three CDM groups as there are three TRPs transmitting PDSCHs to the UE <NUM> although only two TRPs are transmitting PDCCHs. Hence, the multi-PDCCH example in <FIG> is not suitable for DMRS type <NUM> which is the mandatory DMRS configuration in NR since DMRS type <NUM> has two CDM groups while the example in <FIG> requires <NUM> CDM groups.

By this embodiment, in the MAC CE activating/deactivating TCI states for PDSCH for this serving cell, the UE <NUM> receives a mapping of at most one TCI state for each of the codepoints in the DCI Transmission Configuration Indication field, if the serving cell indicated in the MAC CE is configured for multi-PDCCH based PDSCH reception.

A key benefit of this embodiment is that it makes multi-PDCCH based multi-TRP transmission suitable for DMRS type <NUM> which is the mandatory DMRS configuration in NR. That is, since at most one TCI state is mapped to each of the codepoints in the DCI Transmission Configuration Indication field, each of the multi-PDCCHs (e.g., two PDCCHs) received by the UE <NUM> will only indicate one TCI state and will use only one DMRS CDM group (recall, one DMRS CDM group is needed per TCI state). In the case of two PDCCHs, this amounts to using two DMRS CDM groups which is what is supported in NR DMRS type <NUM>.

Even though the restriction of mapping/indication of at most one TCI state for each of the codepoints in the DCI Transmission Configuration Indication field is described on a per serving cell basis in this embodiment, this restriction can also be applied on a per BWP basis in an alternative embodiment. In this alternative embodiment, if a given BWP with identity given by 'BWP ID', as indicated in the MAC CE activating/deactivating TCI states for PDSCH is configured for multi-PDCCH based PDSCH reception, then the UE <NUM> receives a mapping of at most one TCI state for each of the codepoints in the DCI Transmission Configuration Indication field.

In another embodiment, if a given serving cell with identity given by 'Serving Cell ID' indicated in the MAC CE activating/deactivating TCI states for PDSCH for this serving cell is configured for single-PDCCH based multi-PDSCH reception (or a PDSCH reception with two sets of layers each associated with a different TCI state), then the UE <NUM> receives a mapping with more than one TCI state mapped/indicated for at least one codepoint in the DCI Transmission Configuration Indication field.

Next, some MAC CE examples applying this embodiment are shown. In these examples, Serving Cell with ID = X is configured to receive multi-PDCCH based PDSCHs while Serving cell ID =Y is configured to receive single-PDCCH based PDSCHs.

A first example MAC CE applying the restriction in Embodiment <NUM> is shown in <FIG>. In this example, TCI state IDi,j denotes the jth TCI state indicated for the ith codepoint in the DCI Transmission Configuration Indication field. Furthermore, the Ci,j field indicates if a (j+<NUM>)th TCI state associated with the ith codepoint in the DCI Transmission Configuration Indication field will be present in the MAC CE. Given that Serving Cell with ID = X is configured to receive multi-PDCCH based PDSCHs, there is only one TCI state per codepoint of the DCI Transmission Configuration Indication field in this example. That is, the Ci,<NUM> fields corresponding each codepoint do not indicate the presence of a <NUM>nd TCI state associated with that codepoint.

A second example MAC CE applying the restriction in Embodiment <NUM> is shown in <FIG>. In this example, TCI state IDi,j denotes the jth TCI state indicated for the ith codepoint in the DCI Transmission Configuration Indication field. Furthermore, the Ci,j field indicates if a (j+<NUM>)th TCI state associated with the ith codepoint in the DCI Transmission Configuration Indication field will be present in the MAC CE. Given that Serving Cell with ID = Y is configured to receive single-PDCCH based PDSCHs, there can be one or more TCI states per codepoint of the DCI Transmission Configuration Indication field in this example. For instance,.

A third example MAC CE applying the restriction in Embodiment <NUM> is shown in <FIG>. In this example, the Si field indicates the number of TCI states associated with the ith codepoint in the DCI Transmission Configuration Indication field. In the example of <FIG>, Si = <NUM> means that the ith codepoint in the DCI Transmission Configuration Indication field is mapped to one TCI state. If Si = <NUM>, then the ith codepoint in the DCI Transmission Configuration Indication field is mapped to two TCI states. The byte containing the Si fields is only present if the Serving Cell is configured to receive single-PDCCH based PDSCHs, and the Si fields are missing from the MAC CE if the Serving Cell is configured to receive multi-PDCCH based PDSCHs. In this example, the mapping of TCI states to codepoints in the TCI Transmission Configuration Indication field are given as follows:.

Note that although the third example shows one or two TCI states being mapped to a codepoint in the DCI Transmission Configuration Indication field, the example can also extended to more than two TCI states being mapped to a codepoint in the DCI Transmission Configuration Indication field. To extend this example to mapping up to four TCI states per codepoint in the DCI Transmission Configuration Indication field, a pair of bits Si1Si0 in place of Si in the indicated MAC CE. The pair of bits Si1Si0 can indicate whether <NUM>, <NUM>, <NUM>, or <NUM> TCI states are mapped to the ith codepoint in the DCI Transmission Configuration Indication field.

In some cases, the maximum number of activated TCI states can be limited to a certain number Tmax so that the UE <NUM> is only limited to receive transmissions corresponding to this limited number of TCI states. Hence, in some variants of Embodiment <NUM>, the maximum number of unique TCI state IDs indicated by the MAC CE is limited to Tmax. In NR Rel-<NUM>, Tmax is agreed to be eight (<NUM>). <FIG> shows an example MAC CE where <NUM> TCI state IDs are indicated with the following mappings to codepoints in the DCI Transmission configuration indication field:.

Even though <NUM> TCI states are indicated, the maximum number of unique TCI states indicated (i.e., TCI states A, B, C, D, E, F, G, and H) by the MAC CE is limited to <NUM> according to this embodiment.

<FIG> illustrates the operation of a network node and a UE <NUM> in accordance with at least some aspects of at least some of the embodiments described above. Optional steps are indicated by dashed lines/boxes. Note that the network node may be a network node that provides joint scheduling for multiple TRPs for a multi-PDSCH transmission (see, e.g., <FIG>). The network node may, for example, be a base station <NUM> that serves as one of the TRPs for a multi-PDSCH transmission (where the other TRP(s) for the multi-PDSCH transmission may be, e.g., another base station <NUM> or a low power node <NUM>). Alternatively, in the case of separate scheduling for a multi-PDSCH transmission (see, e.g., <FIG>), the network node may be, e.g., a network node in which the separate schedulers are implemented or may alternatively be divided into multiple network nodes at which the respective schedulers are implemented (i.e., the functions shown in <FIG> as being performed by the "network node" may, in some embodiments, be performed by two or more network nodes). As another alternative, this case, separate network nodes for separate TRPs may each perform the functions of <FIG> as they pertain to the PDSCH/PDSH layer group transmission of the respective TRP.

As illustrated, the network node configures the UE <NUM> with one or more serving cells (step <NUM>). The configured serving cell(s) include: (a) one or more first serving cells configured for multi-PDCCH based multi-PDSCH reception, (b) one or more second serving cells configured for single-PDCCH based multi-PDSCH reception, or (c) both (a) and (b).

The network node sends, or causes to be sent, a MAC CE to the UE <NUM>, where this MAC CE is a MAC CE for which TCI state activation/deactivation for PDSCH applies (step <NUM>). As described above, the MAC CE includes information that indicates one or more TCI states that are activated for at least one of the configured serving cells or the respective BWP. In addition, the network node sends, or causes to be sent, to the UE <NUM> information that indicates mappings between the activated TCI states and codepoints of the TCI field of DCI, as described above (step <NUM>). As discussed above, in some embodiments, this information of step <NUM> is also provided in the MAC CE of step <NUM>. As further described above, in this information, a restriction on the maximum number of TCI states that can be mapped to any codepoint in the TCI field of DCI is applied. This restriction is a function of whether the at least one configured serving cell or respective BWP(s) for which the TCI state(s) are activated is configured for multi-PDCCH based multi-PDSCH reception or single-PDCCH based multi-PDSCH reception, as described above. For example, as described above, in some embodiments, the maximum number is restricted to <NUM> for multi-PDCCH based multi-PDSCH reception and restricted to <NUM> for single-PDCCH based multi-PDSCH reception.

The network node may transmit, or cause transmission of, DCI(s) to the UE <NUM> for a multi-PDSCH transmission (step <NUM>). The DCI(s) includes a respective TCI field that is set to a particular codepoint. This codepoint is mapped to one or more TCI states by the information in step <NUM>. The UE <NUM> determines the TCI state(s) for the multi-PDSCH transmission based on the codepoint(s) in the TCI field(s) of the received DCI(s) and the mappings indicated by the information from step <NUM> (step <NUM>). The network node transmits or causes transmission of the multi-PDSCH transmission, and the UE receives the multi-PDSCH transmission, in accordance with the indicated TCI state(s) (step <NUM>).

In RAN1#98bis, the following conclusion and agreement were made in 3GPP RAN1:.

For the agreed feature of single MAC-CE to activate at least the same set of PDSCH TCI state IDs for multiple CCs/BWPs,.

When a set of TCI-state IDs for PDSCH are activated by a MAC CE for a set of CCs/BWPs at least for the same band, where the applicable list of CCs is indicated by RRC signalling, the same set of TCI-state IDs are applied for the all BWPs in the indicated CCs.

The intention of the above conclusion/agreement is to reduce the signaling overhead for activating TCI states for a set of component carriers (CCs) or BWPs. That is, instead of sending a different MAC CE for a serving cell/BWP combination, this new agreement allows a set of TCI State-IDs for PDSCH to be activated by MAC CE for a set of CCs/BWPs. It was further agreed to introduce two lists of CCs for which simultaneous TCI state ID activation across multiple CCs/BWPs by MAC CE is applied. However, the above agreements are for the case of single TRP.

To define simultaneous TCI state ID activation across a set of CCs/BWPs for multi-TRP case, then the cases of multi-PDCCH based multi-TRP and single-PDCCH based multi-TRP need to be considered. In one embodiment, all the CCs in a list of CCs to be used for simultaneous TCI State-ID update should only involve CCs that have either multi-PDCCH based multi-TRP transmission enabled or single-PDCCH based multi-TRP transmission enabled.

A first example MAC CE applying the restriction in Embodiment <NUM> is shown in <FIG>. In this example, TCI state IDi,j denotes the jth TCI state indicated for the ith codepoint in the DCI Transmission Configuration Indication field. Furthermore, the Ci,j field indicates if a (j+<NUM>)th TCI state associated with the ith codepoint in the DCI Transmission Configuration Indication field will be present in the MAC CE. In this example, the CCs in the list with simultaneousTCI-CellListId = U are all configured to receive single-PDCCH based PDSCHs. Hence, there can be one or more TCI state per codepoint of the DCI Transmission Configuration Indication field in this example. For instance,.

In another embodiment, RRC configured simultaneousTCI-CellListId is not needed, but a more flexible way of providing serving cell IDs is provided as illustrated in <FIG>. In <FIG>, the M field indicates whether or not there is an additional serving cell ID in a group of cells. The value '<NUM>' indicates there is an additional serving cell ID in a group of cells whose TCI state IDs are downselected for the DCI codepoints in the rest of the octets. The value '<NUM>' indicates the serving cell ID in the current octet is the last in the group of cells. The group of cells consists of N cells which are given as (N-<NUM>) serving cell IDs with serving cell IDs corresponding to F=<NUM> in consecutive octets and an additional serving cell whose serving cell ID is given in the following Octet with F=<NUM>. Note that even though the M field is described here in context of a PDSCH MAC CE, it can be applied in a PDCCH MAC CE. The only difference is that, instead of giving TCI states mapping to DCI codepoints, the MAC CE gives TCI state for all the PDCCH of the serving cell and BWP listed.

<FIG> illustrates the operation of a network node and a UE <NUM> in accordance with at least some aspects of at least some of the embodiments described above. Optional steps are indicated by dashed lines/boxes. Note that the network node may be a network node that provides joint scheduling for multiple TRPs for a multi-PDSCH transmission (see, e.g., <FIG>). The network node may, for example, be a base station <NUM> that serves as one of the TRPs for a multi-PDSCH transmission (where the other TRP(s) for the multi-PDSCH transmission may be, e.g., another base station <NUM> or a low power node <NUM>). Alternatively, in the case of separate scheduling for a multi-PDSCH transmission (see, e.g., <FIG>), the network node may be, e.g., a network node in which the separate schedulers are implemented or may alternatively be divided into multiple network nodes at which the respective schedulers are implemented (i.e., the functions shown in <FIG> as being performed by the "network node" may, in some embodiments, be performed by two or more network nodes). As another alternative, separate network nodes for separate TRPs may each perform the functions of <FIG> as they pertain to the PDSCH/PDSH layer group transmission of the respective TRP.

As illustrated, the network node may configure the UE <NUM> with a list of CCs for which simultaneous TCI state updates are enabled (step <NUM>). As discussed above, the list of CCs is restricted to (i.e., only includes) CCs that have either multi-PDCCH based multi-PDSCH transmission or single-PDCCH based multi-PDSCH transmission enabled. The network node transmits or initiates transmission of a MAC CE for TCI state activation or deactivation to the UE <NUM>, and the UE <NUM> receives the MAC CE (step <NUM>). As discussed above, the MAC CE includes information that (simultaneously) activates one or more TCI states for all of the CCs included in the list of CCs for which simultaneous TCI state updates are enabled. In addition, as described herein, the information included in the MAC CE maps at most X (e.g., X=<NUM>) of the TCI states activated by the MAC CE to each of the codepoints for the DCI Transmission Configuration Indication field.

The network node may transmit or initiate transmission of a PDCCH including a DCI in which the DCI Transmission Configuration Indication field is set to a particular codepoint that is mapped to the TCI state(s) to be used for at least one PDSCH scheduled by the DCI, and the UE <NUM> receives the PDCCH (step <NUM>). The PDCCH is for either a multi-PDCCH based multi-PDSCH transmission or a single-PDCCH based multi-PDSCH transmission using at least one of the CCs in the configured list of CCs for simultaneous TCI state update. The UE <NUM> determines the activated TCI state(s) that are mapped to the particular codepoint for the DCI Transmission Configuration Indication field included in the received DCI (step <NUM>). The determined TCI state(s) are then used for transmission of the scheduled PDSCH(s) and used by the UE <NUM> for reception of the scheduled PDSCH(s) (step <NUM>).

In some scenarios, the maximum number of TCI states that can be activated can be larger than the number of codepoints in the DCI Transmission Configuration Indication field. Consider the case where there are Tmax = <NUM> TCI states that can be activated and multi-PDCCH based PDSCH reception is configured for a given serving cell. And, consider the case where there are two bits in the DCI Transmission Configuration Indication field which corresponds to four codepoints. In this case, it is possible to activate four TCI states to be used with the first PDCCH scheduling the first PDSCH, and to activate another four TCI states to be used with the second PDCCH scheduling the second PDSCH. However, when such activation of different sets of TCI states are provided via MAC CE, the UE <NUM> needs to know which PDCCH the TCI states activated via MAC CE should be used with.

The maximum number of unique TCI state IDs indicated by the MAC CE is limited to Tmax. In NR Rel-<NUM>, Tmax is agreed to be eight (<NUM>). <FIG> shows an example MAC CE where <NUM> TCI state IDs are indicated with the following mappings to codepoints in the DCI Transmission configuration indication field.

Since each CORESET pool consisting of one or more CORESETs corresponds to one TRP transmitting a PDCCH, then in one embodiment, the CORESET pool index may be indicated as part of the MAC CE. From the CORESET pool index, the UE <NUM> knows that the activated TCI States and the associated codepoint to TCI state mapping should be applied to a PDCCH that is carried within one of the CORESETs in the CORESET pool. The benefit of this embodiment is that the TCI state activation and codepoint to TCI state mapping for two TRPs that sends two PDCCHs to the UE <NUM> can be provided to the UE <NUM> via independent MAC CEs.

In an alternative embodiment, TCI state activation and codepoint to TCI state mapping for two TRPs can be simultaneously provided within the same MAC CE. This is done by indicating a set of TCI state IDs to be activated and, for each of the TCI state IDs, indicating an associated CORESET pool index for the TCI state ID.

In yet another alternative embodiment, the CORESET pool index associated with a MAC CE that activates TCI states and provides codepoint to TCI state mapping for a TRP can be provided implicitly. The CORESET pool index is known to the UE <NUM> as the pool of the CORESET that carries the PDCCH which is used to schedule the PDSCH carrying the TCI state indication MAC CE.

As illustrated, the network node transmits or initiates transmission of a MAC CE for TCI state activation or deactivation to the UE <NUM>, and the UE <NUM> receives the MAC CE (step <NUM>). As discussed above, the MAC CE includes information that activates one or more TCI states and defines a codepoint to TCI state mapping that maps each of the codepoints of the DCI Transmission Configuration Indication field to at most X (e.g., X=<NUM>) of the TCI states activated by the MAC CE. In addition, as described above, in one embodiment the MAC CE includes a CORESET pool ID that indicates that the TCI states activated by the MAC CE and the codepoint to TCI state mapping defined by the information included in the MAC CE are to be applied to a PDCCH(s) that is carried within any CORESET in the CORESET pool indicated by the CORESET pool ID.

The network node may transmit or initiate transmission of a PDCCH carried within a CORSET in the CORESET pool indicated by the CORESET pool ID (step <NUM>). The PDCCH includes a DCI in which the DCI Transmission Configuration Indication field is set to a particular codepoint that is mapped to the TCI state(s) to be used for at least one PDSCH scheduled by the DCI, and the UE <NUM> receives the PDCCH. The UE <NUM> determines the activated TCI state(s) that are mapped to the particular codepoint for the DCI Transmission Configuration Indication field included in the received DCI (step <NUM>). The determined TCI state(s) are then used for transmission of the scheduled PDSCH(s) and used by the UE <NUM> for reception of the scheduled PDSCH(s) (step <NUM>).

<FIG> is a schematic block diagram of a network node <NUM> according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The network node <NUM> may be, for example, the network node of <FIG> (which may be, e.g., a radio network node such as, e.g., a base station <NUM> or <NUM>), a network node that implements all or part of the functionality of the network node of <FIG>, as described herein. As illustrated, the network node <NUM> includes a control system <NUM> that includes one or more processors <NUM> (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory <NUM>, and a network interface <NUM>. The one or more processors <NUM> are also referred to herein as processing circuitry. In addition, if the network node <NUM> is a radio access node, the network node <NUM> may include one or more radio units <NUM> that each includes one or more transmitters <NUM> and one or more receivers <NUM> coupled to one or more antennas <NUM>. The radio units <NUM> may be referred to or be part of radio interface circuitry. In some embodiments, the radio unit(s) <NUM> is external to the control system <NUM> and connected to the control system <NUM> via, e.g., a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit(s) <NUM> and potentially the antenna(s) <NUM> are integrated together with the control system <NUM>. The one or more processors <NUM> operate to provide one or more functions of a network node <NUM> as described herein (e.g., one or more functions of the network node as described above, e.g., with respect to <FIG>). In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory <NUM> and executed by the one or more processors <NUM>.

<FIG> is a schematic block diagram that illustrates a virtualized embodiment of the network node <NUM> according to some embodiments of the present disclosure. As used herein, a "virtualized" network node is an implementation of the network node <NUM> in which at least a portion of the functionality of the network node <NUM> is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node <NUM> includes one or more processing nodes <NUM> coupled to or included as part of a network(s) <NUM>. Each processing node <NUM> includes one or more processors <NUM> (e.g., CPUs, ASICs, FPGAs, and/or the like), memory <NUM>, and a network interface <NUM>. In addition, if the network node <NUM> is a radio access node, the network node <NUM> may include the control system <NUM> and/or the one or more radio units <NUM>, as described above. If present, the control system <NUM> or the radio unit(s) is connected to the processing node(s) <NUM> via the network <NUM>.

In this example, functions <NUM> of the network node <NUM> described herein (e e.g., one or more functions of the network node as described above, e.g., with respect to <FIG>) are implemented at the network processing nodes <NUM> or distributed across the one or more processing nodes <NUM> and the control system <NUM> and/or the radio unit(s) <NUM> in any desired manner. In some particular embodiments, some or all of the functions <NUM> of the network node <NUM> described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment(s) hosted by the processing node(s) <NUM>. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) <NUM> and the control system <NUM> is used in order to carry out at least some of the desired functions <NUM>. Notably, in some embodiments, the control system <NUM> may not be included, in which case the radio unit(s) <NUM> communicate directly with the processing node(s) <NUM> via an appropriate network interface(s).

In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of network node <NUM> or a node (e.g., a processing node <NUM>) implementing one or more of the functions <NUM> of the network node <NUM> in a virtual environment according to any of the embodiments described herein (e e.g., one or more functions of the network node as described above, e.g., with respect to <FIG>) is provided.

<FIG> is a schematic block diagram of the network node <NUM> according to some other embodiments of the present disclosure. The network node <NUM> includes one or more modules <NUM>, each of which is implemented in software. The module(s) <NUM> provide the functionality of the network node <NUM> described herein (e.g., one or more functions of the network node as described above, e.g., with respect to <FIG>).

<FIG> is a schematic block diagram of a wireless communication device <NUM> according to some embodiments of the present disclosure. The wireless communication device <NUM> may be, e.g., the UE <NUM> or UE described herein. As illustrated, the wireless communication device <NUM> includes one or more processors <NUM> (e.g., CPUs, ASICs, FPGAs, and/or the like), memory <NUM>, and one or more transceivers <NUM> each including one or more transmitters <NUM> and one or more receivers <NUM> coupled to one or more antennas <NUM>. The transceiver(s) <NUM> includes radio-front end circuitry connected to the antenna(s) <NUM> that is configured to condition signals communicated between the antenna(s) <NUM> and the processor(s) <NUM>, as will be appreciated by on of ordinary skill in the art. The processors <NUM> are also referred to herein as processing circuitry. The transceivers <NUM> are also referred to herein as radio circuitry. In some embodiments, the functionality of the wireless communication device <NUM> described above (e.g., one or more functions of the UE <NUM> described above with respect to Embodiments <NUM>-<NUM> and <FIG>) may be fully or partially implemented in software that is, e.g., stored in the memory <NUM> and executed by the processor(s) <NUM>. Note that the wireless communication device <NUM> may include additional components not illustrated in <FIG> such as, e.g., one or more user interface components (e.g., an input/output interface including a display, buttons, a touch screen, a microphone, a speaker(s), and/or the like and/or any other components for allowing input of information into the wireless communication device <NUM> and/or allowing output of information from the wireless communication device <NUM>), a power supply (e.g., a battery and associated power circuitry), etc..

In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of the wireless communication device <NUM> according to any of the embodiments described herein (e.g., one or more functions of the UE <NUM> described above with respect to Embodiments <NUM>-<NUM> and <FIG>) is provided.

The module(s) <NUM> provide the functionality of the wireless communication device <NUM> described herein (e.g., one or more functions of the UE <NUM> described above with respect to Embodiments <NUM>-<NUM> and <FIG>).

With reference to <FIG>, in accordance with an embodiment, a communication system includes a telecommunication network <NUM>, such as a 3GPP-type cellular network, which comprises an access network <NUM>, such as a RAN, and a core network <NUM>. The access network <NUM> comprises a plurality of base stations 2806A, 2806B, 2806C, such as Node Bs, eNBs, gNBs, or other types of wireless Access Points (APs), each defining a corresponding coverage area 2808A, 2808B, 2808C. Each base station 2806A, 2806B, 2806C is connectable to the core network <NUM> over a wired or wireless connection <NUM>. A first UE <NUM> located in coverage area 2808C is configured to wirelessly connect to, or be paged by, the corresponding base station 2806C. A second UE <NUM> in coverage area 2808A is wirelessly connectable to the corresponding base station 2806A.

It is noted that the host computer <NUM>, the base station <NUM>, and the UE <NUM> illustrated in <FIG> may be similar or identical to the host computer <NUM>, one of the base stations 2806A, 2806B, 2806C, and one of the UEs <NUM>, <NUM> of <FIG>, respectively.

The wireless connection <NUM> between the UE <NUM> and the base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE <NUM> using the OTT connection <NUM>, in which the wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve, e.g., the data rate and thereby provide benefits such as, e.g., reduced user waiting time.

Claim 1:
A method performed by a wireless communication device (<NUM>, <NUM>) in a cellular communications system (<NUM>), the method comprising:
• receiving (<NUM>), from a network node (<NUM>), a Medium Access Control, MAC, Control Element, CE, for Transmission Configuration Indication, TCI, state activation or deactivation, the MAC CE comprising:
o information that:
▪ activates one or more TCI states;
▪ defines a codepoint to TCI state mapping, wherein the codepoint to TCI state mapping maps each of a plurality of codepoints for a Downlink Control information, DCI, transmission configuration indication field to at most X of the one or more TCI states activated by the MAC CE, where X is an integer greater than or equal to <NUM>; and
o a control resource set, CORESET, pool identity, ID, that indicates that the one or more TCI states activated by the MAC CE and the codepoint to TCI state mapping defined by the information comprised in the MAC CE are to be applied to a physical downlink control channel, PDCCH, that is carried within any CORESET in a CORESET pool indicated by the CORESET pool ID;
• receiving (<NUM>) a PDCCH carried within a CORESET in the CORESET pool indicated by the CORESET pool ID, the PDCCH comprising a DCI in which the DCI transmission configuration field is set to a particular codepoint from among the plurality of codepoints for the DCI transmission configuration field; and
• determining (<NUM>) a TCI state from among the one or more TCI states activated by the MAC CE used for a PDSCH scheduled by the DCI based on the information comprised in the DCI.