WO2021095025A1

WO2021095025A1 - Mac ce for indicating default qcl for multi-trp

Info

Publication number: WO2021095025A1
Application number: PCT/IB2020/060791
Authority: WO
Inventors: Siva Muruganathan; Helka-Liina MÄÄTTÄNEN; Shiwei Gao; Mattias Frenne
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2019-11-15
Filing date: 2020-11-16
Publication date: 2021-05-20

Abstract

Systems and methods for Medium Access Control (MAC) Control Element (CE) for indicating default Quasi Co-Located (QCL) for multi-Transmission Reception Point (TRP) are provided. In some embodiments, a method for receiving Transmission Configuration Indication (TCI) state activation for Physical Downlink Data Channel (PDSCH) via MAC CE includes: transmitting an indication of a time duration threshold; receiving a configuration; receiving a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of resources corresponding to the first TCI state indicated in the TCI field in DL DCI using a first default TCI state; and/or receiving a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of resources corresponding to the second TCI state indicated in the TCI field in DL DCI using a second default TCI state provided as part of a MAC CE that activates the TCI states for PDSCH.

Description

MAC CE FOR INDICATING DEFAULT QCL FOR MULTI-TRP

Related Applications

[0001] This application claims the benefit of provisional patent application serial number 62/936,162, filed November 15, 2019, the disclosure of which is hereby incorporated herein by reference in its entirety.

Technical Field

[0002] The present disclosure relates to default Quasi Co-Located (QCL) assumptions.

Background

[0003] The new generation mobile wireless communication system (5G) or new radio (NR) supports a diverse set of use cases and a diverse set of deployment scenarios. [0004] NR uses CP-OFDM (Cyclic Prefix Orthogonal Frequency Division Multiplexing) 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 DFT-spread 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 1ms each. A subframe is further divided into multiple slots of equal duration.

[0005] The slot length depends on subcarrier spacing. For subcarrier spacing of Af = 15 kHz, there is only one slot per subframe, and each slot always consists of 14 OFDM symbols, irrespectively of the subcarrier spacing.

[0006] Typical data scheduling in NR are per slot basis, an example is shown in Figure 1 (which illustrates NR time-domain structure with 15 kHz subcarrier spacing) where the first two symbols contain physical downlink control channel (PDCCH) and the remaining 12 symbols contains Physical Data Channel (PDCH), either a Physical Downlink Data Channel (PDSCH) or Physical Uplink Data Channel PUSCH).

[0007] Different subcarrier spacing values are supported in NR. The supported subcarrier spacing values (also referred to as different numerologies) are given by Af = (15 x 2^a) kHz where a is a non-negative integer. Af = 15 kHz is the basic subcarrier spacing that is also used in LTE. The slot durations at different subcarrier spacings are shown in the table below: Slot length at different numerologies.

[0008] In the frequency domain physical resource definition, a system bandwidth is divided into resource blocks (RBs); each corresponds to 12 contiguous subcarriers. The Common RBs (CRBs) are numbered starting with 0 from one end of the system bandwidth. The UE is configured with one or up to four Bandwidth Part (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, the CRB 0. Hence, a UE can be configured a narrow BWP (e.g., 10 MHz) and a wide BWP (e.g., 100 MHz), but only one BWP can be active for the UE at a given point in time. The physical RB (PRB) are numbered from 0 to N-l within a BWP (but the 0:th PRB may thus be the K:th CRB where K>0).

[0009] The basic NR physical time-frequency resource grid is illustrated in Figure 2, where only one Resource Block (RB) within a 14-symbol slot is shown. One OFDM subcarrier during one OFDM symbol interval forms one Resource Element (RE).

[0010] Downlink transmissions can be dynamically scheduled, i.e., in each slot the gNB transmits Downlink Control Information (DCI) over 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 are carried on PDSCH. A UE first detects and decodes PDCCH and the decoding is successfully, it then decodes the corresponding PDSCH based on the decoded control information in the PDCCH.

[0011] 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.

OCL and TCI states

[0012] 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).

[0013] 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 CSI-RS (known as source RS) and the second antenna port is a Demodulation Reference Signal (DMRS) (known as target RS) for PDSCH or PDCCH reception.

[0014] 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 Reference Signal (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.

[0015] 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:

• Type A: {Doppler shift, Doppler spread, average delay, delay spread}

• Type B: {Doppler shift, Doppler spread}

• Type C: {average delay, Doppler shift}

• Type D: {Spatial Rx parameter}

[0016] 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 Rx beam to receive them. This is helpful for a UE that use analog beamforming to receive signals, since the UE need 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 also safely use the same RX beam to receive 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.

[0017] 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 SINR. In many cases, this means that the TRS must be transmitted in a suitable beam to a certain UE.

[0018] To introduce dynamics in beam and Transmission Reception Point (TRP) selection, the UE can be configured through RRC signalling with M TCI states, where M is up to 128 in frequency range 2 (FR2) for the purpose of PDSCH reception and up to 8 in FR1, depending on UE capability.

[0019] Each TCI state contains QCL information, i.e., one or two source 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-Typel,qcl-Type2} = {Type A, Type D}. It means the UE can derive Doppler shift, Doppler spread, average delay, and delay spread from CSI-RS1 and Spatial Rx parameter (i.e., the RX beam to use) from CSI- RS2.

[0020] 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.

[0021] 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 MAC CE one TCI state for PDCCH (i.e., provides a TCI for PDCCH) and up to eight active TCI states for PDSCH. The number of active TCI states the UE support is a UE capability, but the maximum is 8.

[0022] Each configured TCI state contains parameters for the quasi co-location associations between source reference signals (CSI-RS or SS/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.

[0023] Assume a UE is configured with 4 active TCI states (from a list of totally 64 configured TCI states). Hence, 60 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

[0024] Demodulation reference signals are used for coherent demodulation of physical layer data channels, PDSCH (DL) and PUSCH (UL), as well as of physical layer downlink control channel PDCCH. The DM-RS 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.

[0025] The mapping of DM-RS to resource elements is configurable in terms of density both frequency and time domain, with two mapping types in the frequency domain (configuration Type 1 or Type 2) and two mapping types in the time domain (mapping type A or type B) defining the symbol position of the first DM-RS within a transmission interval. The DM-RS mapping in time domain can further be single-symbol based or double-symbol based where the latter means that DM-RS is mapped in pairs of two adjacent symbols. Furthermore, a UE can be configured with one, two, three or four single-symbol DM-RS and one or two double-symbol DM-RS. In scenarios with low Doppler, it may be sufficient to configure front-loaded DM-RS only, i.e., one single- symbol DM-RS or one double-symbol DM-RS, whereas in scenarios with high Doppler additional DM-RS will be required.

[0026] Figure 3 shows the mapping of front-loaded DM-RS for configuration Type 1 and Type 2 with single-symbol and double-symbol DM-RS and for the mapping type A with first DM-RS in third symbol of a transmission interval of 14 symbols. We observe from this figure that Type 1 and Type 2 differs with respect to both the mapping structure and the number of supported DM-RS CDM groups where Type 1 support two CDM groups and Type 2 support three CDM groups.

TCI states Activation/Deactivation for UE-specific PDSCH via MAC CE [0027] Now we provide the details of the MAC CE signaling that is used to activate/deactivate TCI states for UE specific PDSCH. The structure of the MAC CE for activating/deactivating TCI states for UE specific PDSCH is given in Figure 4. Figure 4 illustrates TCI States Activation/Deactivation for UE-specific PDSCH MAC CE (Extracted from Figure 6.1.3.14-1 of 3GPP TS 38.321).

[0028] As shown in Figure 4, the MAC CE contains the following fields:

• Serving Cell ID: This field indicates the identity of the Serving Cell for which the MAC CE applies. The length of the field is five bits;

• BWP ID: This field contains the ID corresponding to a downlink bandwidth part for which the MAC CE applies. The BWP ID is given by the higher layer parameter BWP-Id as specified in 3GPP TS 38.331. The length of the BWP ID field is two bits since a UE can be configured with up to four BWPs for DL;

• A variable number of fields T: If the UE is configured with a TCI state with TCI State ID i, then the field T indicates the activation/deactivation status of the TCI state with TCI State ID i. If the UE is not configured with a TCI state with TCI State ID i, the MAC entity shall ignore the T, field. The T, field is set to "1" to indicate that the TCI state with TCI State ID i shall be activated and mapped to the codepoint of the DCI Transmission Configuration Indication (TCI) field, as specified in 3GPP TS 38.214. The T field is set to "0" to indicate that the TCI state with TCI State ID i shall be deactivated and is not mapped to the codepoint of the DCI Transmission Configuration Indication field. It should be noted that the codepoint to which the TCI State is mapped is determined by the ordinal position among all the TCI States with T, field set to "1". That is the first TCI State with T field set to "1" shall be mapped to the codepoint value 0 of DCI Transmission Configuration Indication field, the second TCI State with T field set to "1" shall be mapped to the codepoint value 1 of DCI Transmission Configuration Indication field, and so on. In NR Rel-15, the maximum number of activated TCI states is 8;

• A Reserved bit R: this bit is set to Ό' in NR Rel-15.

[0029] Note that the TCI States Activation/Deactivation for UE-specific PDSCH MAC CE is identified by a MAC PDU subheader with logical channel ID (LCID) as specified in Table 6.2.1-1 of 3GPP TS 38.321 (this table is reproduced below in Table 1). The MAC CE for Activation/ Deactivation of TCI States for UE-specific PDSCH has variable size.

Table 1 Values of LCID for DL-SCH (Extracted from Table 6.2.1-1 of 3GPP TS 38.321)

PDSCH transmission over multiple transmission points or panels (TRP) [0030] In one scenario, downlink data are transmitted over multiple TRPs in which different MIMO layers are transmitted over different TRPs. This is referred to a Non^¬ coherent Joint Transmission (NC-JT). In another scenario, different time/frequency resources may be allocated to different TRPs and one or multiple PDSCH is transmitted over different TRPs. Two ways of scheduling multi-TRP transmission are specified in NR Rel-16: multi-PDCCH based multi-TRP transmission and single-PDCCH based multi-TRP transmission.

Multi-PDCCH based multi-TRP transmission

[0031] Figure 5 illustrates an example of multi-PDCCH based multi-TRP transmission with a single scheduler. An example is shown in Figure 5, where data are sent to a UE over two TRPs, each TRP carrying one TB mapped to one code word. When the UE has 4 receive antennas while each of the TRPs has only 2 transmit antennas, the UE can support up to 4 MIMO layers but each TRP can maximally transmit 2 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 4 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.

[0032] In another scenario shown in Figure 6 (which illustrates an example of multi- PDCCH based multi-TRP transmission with independent schedulers), 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.

[0033] In NR specification 3GPP TS 38.211, there is a restriction stating:

[0034] "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."

[0035] 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 MU-MIMO scheduling and UE interference suppression.

[0036] 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 DM- RSs associated with two TRPs will have to belong to different DM-RS CDM groups (as the two PDSCH DM-RSs are not QCL, they cannot belong to the same DM-RS CDM group). Figure 7 illustrates an example relationship between TCI states and DM-RS CDM groups for a multiple-PDCCH multi-TRP scenario. In the example, PDSCH 1 is associated with TCI State p, and PDSCH 2 is associated with TCI state q. The PDSCH DM-RSs from the different TRPs also belong to different DM-RS 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.

[0037] In RAN1#96, the following agreement was made:

Agreement:

[0038] 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

• one CORESET in a "PDCCH-config" corresponds to one TRP o FFS whether to increase the number of CORESETs per "PDCCH-config" more than 3

[0039] FFS: UE monitoring/decoding behavior for multiple PDCCHs.

[0040] According to the above highlighted 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#97, the following was further agreed:

Agreement:

For multi-PDCCH based multi-TRP operation, increase the maximum number of CORESETs per "PDCCH-config" to 5, according to UE capability

• FFS: How to define capability per TRP

• Study whether enhancement of reducing PDCCH blocking rate, e.g., hash function enhancement, and UE complexity is needed, e.g., taking into account overbooking PDCCH candidates and blind detection reduction per TRP/CORESET group.

[0041] According to the above highlighted part in the agreement, the number of CORESETs per 'PDCCH-config' was increased to 5 from 3 (note that 3 is the limit for NR Rel-15) in order to flexibly assign 2-3 CORESETs per TRP. Furthermore, in RAN1#97, 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.

[0042] Hence, in NR Rel-16, 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.

Single-PDCCH based multi-TRP transmission

[0043] 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. Figure 8 shows an example where a DCI received by the UE in PDCCH from TRP1 schedules two PDSCHs. The first PDSCH (PDSCH 1) is received from TRP1 and the second PDSCH (PDSCH2) is received from TRP2. Even though Figure 8 shows 2 PDSCHs being scheduled by a single-PDCCH, the single PDCCH scheme is also applicable for the case where different PDSCH layer sets or different time/frequency resources belonging to the same PDSCH are received from the two TRPs. This is illustrated in the example of Figure 9, where PDSCH layer set 1 is received from TRP1 and PDSCH layer set 2 is received from TRP2.

[0044] 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 Figure 8 and Figure 9, PDSCH 1 and PDSCH layer set 1 are associated with TCI State p. PDSCH 2 and PDSCH layer set 2 are associated with TCI state q. The PDSCH DM-RSs from the different TRPs may belong to different DMRS CDM groups. In the example of Figure 8, the DMRS for PDSCH1 belongs to CDM group u while the DMRS for PDSCH2 belongs to CDM group v. [0045] In the RANI AdHoc meeting in January 2019, the following is agreed: Agreement:

TCI indication framework shall be enhanced in Rel-16 at least for eMBB:

• Each TCI code point in a DCI can correspond to 1 or 2 TCI states o When 2 TCI states are activated within a TCI code point, each TCI state corresponds to one CDM group, at least for DMRS Type 1 ■ FFS design for DMRS Type 2 o FFS: TCI field in DCI, and associated MAC-CE signaling impact

[0046] According to the above agreement, each codepoint in the DCI Transmission Configuration Indication field can be mapped to either 1 or 2 TCI states. This can be interpreted as follows:

[0047] A DCI in PDCCFI schedules 1 or 2 PDSCFIs or PDSCFI layer sets with each PDSCFI or PDSCFI layer set associated with a different TCI state; the codepoint of the Transmission Configuration Indication field in DCI indicates the 1-2 TCI states associated with the 1 or 2 PDSCFIs scheduled.

[0048] Additionally, according to the above agreement, at least for DMRS Type 1, PDSCFI DMRS associated with one TCI state is contained within one DMRS CDM group.

Default OCL assumption in NR Rel-15

[0049] In Release-15 NR, a threshold timeDurationForQCL is reported by the UE based on the UE's capability. The UE may receive in the DCI scheduling the PDSCFI an indication of the TCI state and an indication of the time offset between the reception of the DL DCI and the corresponding PDSCFI. If the TCI state is indicated in DCI scheduling the PDSCFI, the UE uses the indicated TCI state for determining the PDSCFI DMRS antenna ports' quasi co-location when the time offset between the reception of the DL DCI and the corresponding PDSCH is equal to greater than the threshold timeDurationForQCL. When the time offset between the reception of the DL DCI and the corresponding PDSCH is less than the threshold timeDurationForQCL, the UE may assume that the PDSCH DMRS antenna port(s) are quasi-collocated with the RS(s) with respect to the QCL parameter(s) used for PDCCH quasi co-location indication of the CORESET associated with a monitored search space with the lowest CORESET-ID in the latest slot. This assumption of quasi-collocation with the RS(s) of the CORESET with the lowest CORESET-ID is referred to as 'default QCL assumption' in this disclosure. If none of the configured TCI states contains 'QCL-TypeD', the UE uses the indicated TCI state in DCI scheduling PDSCH for determining the PDSCH DMRS antenna ports' quasi co- location irrespective of the time offset between the reception of the DL DCI and the corresponding PDSCH.

[0050] Systems and methods for Medium Access Control (MAC) Control Element (CE) for indicating default Quasi Co-Located (QCL) for multi-Transmission Reception Point (TRP) are provided. In some embodiments, a method performed by a wireless device for receiving Transmission Configuration Indication (TCI) state activation for Physical Downlink Data Channel (PDSCH) via MAC CE. In some embodiments, the method includes one or more of: transmitting an indication of a time duration threshold; receiving a first and/or a second default TCI states in a MAC CE that activates TCI states for PDSCH; receiving a configuration to receive at least one of the following: single-PDCCH based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-PDCCH based scheduling of multiple PDSCHs. The method could also include one or more of: receiving a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the first TCI state indicated in the TCI field in DL DCI using a first default TCI state; and receiving a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the second TCI state indicated in the TCI field in DL DCI using a second default TCI state provided as part of a MAC CE that activates the TCI states for PDSCH.

[0051] Certain aspects of the present disclosure and their embodiments may provide solutions to the aforementioned or other challenges. A solution is proposed where for the default QCL assumption for the PDSCH or the PDSCH layer set corresponding to the 2^nd TCI state indicated in the TCI field in DCI is provided as part of the MAC CE activating/deactivating TCI states for PDSCH.

[0052] In some embodiments, the MAC CE jointly provides one or more of the following: • activation of TCI states for PDSCH;

• mapping of 1 or more than 1 of the activated TCI states to each codepoint of the TCI field in DCI;

• an additional TCI state which provides the default QCL assumption for the PDSCH or the PDSCH layer set corresponding to the 2^nd TCI state indicated in the TCI field in DCI; and

• the default TCI states providing the QCL assumptions for the PDSCH or the PDSCH layer sets corresponding to both the 1^st and the 2^nd TCI states indicated in the TCI field in DCI.

[0053] In some embodiments, the MAC CE jointly provides one or more of the following:

• activation of TCI states for PDSCH;

• an additional TCI state which provides the default QCL assumption for PDSCH or the PDSCH layer set corresponding to the 2^nd TCI state indicated in the TCI field in DCI;

• CORESET pool index.

[0054] In some embodiments, the MAC CE jointly provides one or more of the following:

• activation of TCI states for PDSCH;

• mapping of one or more than one of the activated TCI states to each codepoint of the TCI field in DCI;

• List of serving cells/BWPs where UE applies the values indicated by other fields in the MAC CE. Alternatively, an RRC configured list of cells or BWPs or a combination can be provided.

[0055] In some embodiments, the MAC CE jointly provides one or more of the following: • activation of TCI states for PDSCH;

• CORESET pool index;

[0056] There are, proposed herein, various embodiments which address one or more of the issues disclosed herein. In some embodiments, a method performed by a wireless device for receiving TCI state activation for PDSCH via MAC CE. The method includes one or more of: transmitting an indication of a time duration threshold; receiving a configuration to receive at least one of the following: single-PDCCH based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-PDCCH based scheduling of multiple PDSCHs. The method also might include receiving a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the 1st TCI state indicated in the TCI field in DL DCI using a first default TCI state. The method also might include receiving a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the 2^nd TCI state indicated in the TCI field in DL DCI using a second default TCI state provided as part of a MAC CE that activates the TCI states for PDSCH.

[0057] In some embodiments, a method performed by a base station for indicating TCI state activation for PDSCH via MAC CE. The method includes one or more of: receiving an indication of a time duration threshold; configuring a wireless device to receive at least one of the following: single-PDCCH based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-PDCCH based scheduling of multiple PDSCHs. The method might also include one or more of: scheduling one or more PDSCHs with time offset between the reception of the DL DCI and the corresponding PDSCH or PDSCH layer sets is smaller than the time duration threshold; transmitting a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the 1st TCI state indicated in the TCI field in DL DCI using a first default TCI state; and transmitting a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the 2^nd TCI state indicated in the TCI field in DL DCI using a second default TCI state provided as part of a MAC CE that activates the TCI states for PDSCH. [0058] In some embodiments, the third and the fourth default TCI states are respectively the first default TCI state and the second default TCI state provided in the MAC CE. In some embodiments, the third and the fourth default TCI states are predefined default TCI states. In some embodiments, the first default TCI state is same as or different from the second default TCI state. In some embodiments, the default TCI states are used only when time duration between the DL DCI and the corresponding PDSCH(s) is below the time duration threshold.

[0059] In some embodiments, the time duration threshold comprises timeDurationForQCL.

[0060] In some embodiments, the MAC CE jointly provides the additional QCL assumption along with one or more of the following: activation of TCI states for PDSCH; mapping of one or more activated TCI states per each codepoint of the TCI field in the DL DCI; and a CORESET pool index.

[0061] In some embodiments, the additional QCL assumption is an additional TCI state ID provided in the MAC CE.

[0062] In some embodiments, the additional TCI state ID is indicated separately from the TCI States IDs mapped to the codepoints of the TCI field within the MAC CE. [0063] In some embodiments, the additional TCI state ID is indicated to be one of the TCI States IDs mapped to one of the codepoints of the TCI field within the MAC CE. [0064] In some embodiments, a flag field in the MAC CE indicates if the additional TCI state ID for QCL assumption is present or not in the MAC CE.

[0065] In some embodiments, the first default TCI state is the TCI state of the CORESET associated with a monitored search space with the lowest CORESET-ID in the latest slot. [0066] In some embodiments, the first default TCI state is signaled in the MAC CE together with the second default TCI state.

[0067] In some embodiments, the first and/or the second default TCI state is signaled at the end of the MAC CE entries.

[0068] Certain embodiments may provide one or more of the following technical advantage(s). The proposed solution enables multi-TRP scheduling for URLLC applications in FR2 by defining two default QCL assumptions when the time offset between the reception of the DL DCI and the corresponding PDSCH can be smaller than the threshold timeDurationForQCL.

[0069] The MAC CE proposed in this solution jointly signals the additional default QCL assumption with other information such as activation of TCI states for PDSCH, mapping of 1 or more than 1 of the activated TCI states to each codepoint of the TCI field in DCI, and/or CORESET pool index. Hence, separate MAC CEs do not need to be defined for indicating this information. The number of MAC CEs in NR Rel-15 is already large and 3GPP sees continuous need for new ones. As the LCID (logical channel ID) space is limited, there is a need to limit the number of new MAC CEs introduced whenever possible. The proposed solution provides the benefit that by jointly indicating default QCL assumption with other information, it saves LCID space by circumventing the need for new MAC CEs.

[0070] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

[0071] Figure 1 illustrates New Radio (NR) time-domain structure with 15 kHz subcarrier spacing where the first two symbols contain Physical Downlink Control Channel (PDCCH) and the remaining 12 symbols contains Physical Data Channel (PDCH), either a Physical Downlink Data Channel (PDSCH) or Physical Uplink Data Channel PUSCH);

[0072] Figure 2 illustrates the basic NR physical time-frequency resource grid; [0073] Figure 3 shows the mapping of front-loaded DM-RS for configuration Type 1 and Type 2 with single-symbol and double-symbol DM-RS and for the mapping type A with first DM-RS in third symbol of a transmission interval of 14 symbols; [0074] Figure 4 illustrates the structure of the MAC CE for activating/deactivating Transmission Configuration Indication (TCI) states for UE specific PDSCH;

[0075] Figure 5 illustrates an example of multi-PDCCFI based multi-TRP transmission with a single scheduler;

[0076] Figure 6 illustrates an example of multi-PDCCFI based multi-TRP transmission with independent schedulers;

[0077] Figure 7 illustrates an example relationship between TCI states and DM-RS CDM groups for a multiple-PDCCFI multi-TRP scenario;

[0078] Figure 8 shows an example where a DCI received by the UE in PDCCFI from TRP1 schedules two PDSCFIs;

[0079] Figure 9 illustrates an example where PDSCFI layer set 1 is received from TRP1 and PDSCFI layer set 2 is received from TRP2;

[0080] Figure 10 illustrates one example of a cellular communications system in which embodiments of the present disclosure may be implemented;

[0081] Figure 11 illustrates a method performed by a wireless device for receiving TCI state activation for PDSCFI via MAC CE, according to some embodiments of the present disclosure;

[0082] Figure 12 illustrates a method performed by a base station for indicating TCI state activation for PDSCFI via MAC CE, according to some embodiments of the present disclosure;

[0083] Figure 13 illustrates an example of a MAC CE that jointly provides activation of TCI states for PDSCFI, mapping of activated TCI states to codepoints of TCI field in DCI, and the second default QCL assumption for PDSCFI, according to some embodiments of the present disclosure;

[0084] Figure 14 shows an example MAC CE that can be extended to indicate more than one Default TCI state ID, according to some embodiments of the present disclosure;

[0085] Figure 15 illustrates an example where the second default TCI state is indicated in a MAC CE at the end of the MAC CE table, according to some embodiments of the present disclosure;

[0086] Figure 16 illustrates an example where the UE knows, from the CORESET pool index, 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, according to some embodiments of the present disclosure;

[0087] Figures 17 through 19 are schematic block diagrams of example embodiments of a network node;

[0088] Figures 20 and 21 are schematic block diagrams of example embodiments of a WCD;

[0089] Figure 22 illustrates an example embodiment of a communication system in which embodiments of the present disclosure may be implemented;

[0090] Figure 23 illustrates example embodiments of the host computer, base station, and UE of Figure 22; and

[0091] Figures 24 through 27 are flow charts that illustrate example embodiments of methods implemented in a communication system.

[0092] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0093] Radio Node: As used herein, a "radio node" is either a radio access node or a wireless communication device.

[0094] Radio Access Node: As used herein, a "radio access node" or "radio network node" or "radio access network node" is any node in a Radio Access Network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a New Radio (NR) base station (gNB) in a Third Generation Partnership Project (3GPP) Fifth Generation (5G) NR network or an enhanced or evolved Node B (eNB) in a 3GPP Long Term Evolution (LTE) network), a high-power or macro base station, a low-power base station (e.g., a micro base station, a pico base station, a home eNB, or the like), a relay node, a network node that implements part of the functionality of a base station (e.g., a network node that implements a gNB Central Unit (gNB-CU) or a network node that implements a gNB Distributed Unit (gNB-DU)) or a network node that implements part of the functionality of some other type of radio access node.

[0095] 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 Flome 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.

[0096] Communication Device: As used herein, a "communication device" is any type of device that has access to an access network. Some examples of a communication device include, but are not limited to: mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or Personal Computer (PC). The communication device may be a portable, hand-held, computer-comprised, or vehicle- mounted mobile device, enabled to communicate voice and/or data via a wireless or wireline connection.

[0097] Wireless Communication Device: One type of communication device is a wireless communication device, which may be any type of wireless device that has access to (i.e., is served by) a wireless network (e.g., a cellular network). Some examples of a wireless communication device include but are not limited to: a User Equipment device (UE) in a 3GPP network, a Machine Type Communication (MTC) device, and an Internet of Things (IoT) device. Such wireless communication devices may be, or may be integrated into, a mobile phone, smart phone, sensor device, meter, vehicle, household appliance, medical appliance, media player, camera, or any type of consumer electronic, for instance, but not limited to, a television, radio, lighting arrangement, tablet computer, laptop, or PC. The wireless communication device may be a portable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice and/or data via a wireless connection.

[0098] Network Node: As used herein, a "network node" is any node that is either part of the radio access network or the core network of a cellular communications network/system.

[0099] Note that the description given herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system.

[0100] Note that, in the description herein, reference may be made to the term "cell"; however, particularly with respect to 5G NR concepts, beams may be used instead of cells and, as such, it is important to note that the concepts described herein are equally applicable to both cells and beams.

[0101] Figure 10 illustrates one example of a cellular communications system 1000 in which embodiments of the present disclosure may be implemented. In the embodiments described herein, the cellular communications system 1000 is a 5G system (5GS) including a NR RAN or LTE RAN (i.e., E-UTRA RAN). In this example, the RAN includes base stations 1002-1 and 1002-2, which in 5G NR are referred to as gNBs (e.g., LTE RAN nodes connected to 5GC, which are referred to as gn-eNBs), controlling corresponding (macro) cells 1004-1 and 1004-2. The base stations 1002-1 and 1002-2 are generally referred to herein collectively as base stations 1002 and individually as base station 1002. Likewise, the (macro) cells 1004-1 and 1004-2 are generally referred to herein collectively as (macro) cells 1004 and individually as (macro) cell 1004. The RAN may also include a number of low power nodes 1006-1 through 1006-4 controlling corresponding small cells 1008-1 through 1008-4. The low power nodes 1006-1 through 1006-4 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 1008-1 through 1008-4 may alternatively be provided by the base stations 1002. The low power nodes 1006-1 through 1006-4 are generally referred to herein collectively as low power nodes 1006 and individually as low power node 1006. Likewise, the small cells 1008-1 through 1008-4 are generally referred to herein collectively as small cells 1008 and individually as small cell 1008. The cellular communications system 1000 also includes a core network 1010, which in the 5GS is referred to as the 5G core (5GC). The base stations 1002 (and optionally the low power nodes 1006) are connected to the core network 1010.

[0102] The base stations 1002 and the low power nodes 1006 provide service to wireless communication devices 1012-1 through 1012-5 in the corresponding cells 1004 and 1008. The wireless communication devices 1012-1 through 1012-5 are generally referred to herein collectively as wireless communication devices 1012 and individually as wireless communication device 1012. In the following description, the wireless communication devices 1012 are oftentimes UEs, but the present disclosure is not limited thereto.

[0103] There currently exist certain challenges. When a UE is configured to receive single-PDCCH based multi-TRP transmission, one codepoint in the TCI field in the DCI can indicate either one or two TCI states. When at least one of the codepoints is mapped to two TCI states, then two default QCL assumptions are needed for PDSCH. However, as described above, NR Rel-15 only defines a single default QCL assumption for PDSCH. Hence, it is a problem on how to define/indicate two different default QCL assumptions for PDSCH reception in single PDSCH based multi-TRP operation. This is an important problem that needs to be solved since in FR2 (frequency ranges higher than 6 GHz) and for Ultra Reliable Low Latency Communications (URLLC) applications, the time offset between the reception of the DL DCI and the corresponding PDSCH can be smaller than the threshold timeDurationForQCL.

[0104] Systems and methods for Medium Access Control (MAC) Control Element (CE) for indicating default Quasi Co-Located (QCL) for multi-Transmission Reception Point (TRP) are provided. Figure 11 illustrates a method performed by a wireless device for receiving Transmission Configuration Indication (TCI) state activation for Physical Downlink Data Channel (PDSCH) via MAC CE. In some embodiments, the method includes one or more of: transmitting (step 1100) an indication of a time duration threshold; receiving (1102) a first and/or a second default TCI states in a MAC CE that activates TCI states for PDSCH; receiving (step 1104) a configuration to receive at least one of the following: single-DCI based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-DCI based scheduling of multiple PDSCHs. The method could also include one or more of: receiving (step 1106) a DL DCI and first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the first TCI state indicated in the TCI field in DL DCI using a third default TCI state; and receiving (step 1108) a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the second TCI state indicated in the TCI field in DL DCI using a fourth default TCI state.

[0105] In this way, multi-TRP scheduling for URLLC applications in FR2 is enabled by defining two default QCL assumptions when the time offset between the reception of the DL DCI and the corresponding PDSCH can be smaller than the threshold timeDurationForQCL.

[0106] In some embodiments, the MAC CE jointly signals the additional default QCL assumption with other information such as activation of TCI states for PDSCH, mapping of 1 or more than 1 of the activated TCI states to each codepoint of the TCI field in DCI, and/or CORESET pool index. Hence, separate MAC CEs do not need to be defined for indicating this information. The number of MAC CEs in NR Rel-15 is already large and 3GPP sees continuous need for new ones. As the Logical Channel ID (LCID) space is limited, there is a need to limit the number of new MAC CEs introduced whenever possible. The proposed solution provides the benefit that by jointly indicating default QCL assumption with other information, it saves LCID space by circumventing the need for new MAC CEs.

[0107] Figure 12 illustrates a method performed by a base station for indicating TCI state activation for PDSCH via MAC CE. In some embodiments, the method includes one or more of: receiving (step 1200) an indication of a time duration threshold; configuring (step 1202) a wireless device to receive at least one of the following: single- DCI based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-DCI based scheduling of multiple PDSCHs; transmitting (step 1204) a first and/or a second default TCI states in a MAC CE that activates TCI states for PDSCH; scheduling (step 1206) one or more PDSCHs with a DL DCI where the time offset between the reception of the DL DCI and the corresponding PDSCH or PDSCH layer sets is smaller than the time duration threshold; transmitting (step 1208) the DL DCI and a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the first TCI state indicated in the TCI field in DL DCI using a first default TCI state; and transmitting (step 1210) a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the second TCI state indicated in the TCI field in DL DCI using a fourth default TCI state.

[0108] In some embodiments, when the time offset between the reception of the DL DCI and the corresponding one or multiple PDSCH is smaller than the threshold timeDurationForQCL, the UE assumes that DMRS port(s) associated with the PDSCH, a subset of MIMO layers of the PDSCH, or a subset of time/frequency resource of the PDSCH corresponding to the 1^st TCI state indicated in the TCI field in DCI is or are quasi-collocated with the RS(s) with respect to the QCL parameter(s) used for PDCCH quasi co-location indication of the CORESET associated with a monitored search space with the lowest CORESET-ID in the latest slot. Simply stated, the QCL assumption of the CORESET associated with a monitored search space with the lowest CORESET-ID in the latest slot is used as the default QCL assumption for the PDSCH or the PDSCH layer set or the PDSCH on a subset of time/frequency resource corresponding to the 1^st TCI state indicated in the TCI field in DCI.

[0109] For the default QCL assumption for the PDSCH or the PDSCH layer set or a subset of time/frequency resource corresponding to the 2^nd TCI state indicated in the TCI field in DCI is provided as part of the MAC CE activating/deactivating TCI states for PDSCH. Note that this MAC CE also activates the TCI states for PDSCH and provides the mapping of TCI States to TCI field codepoint in DCI. In this embodiment, the number of TCI states mapped to a codepoint in TCI field can be either 1 or more than 1 (e.g., 2 TCI states mapped to a TCI field codepoint). Hence, in this embodiment, the MAC CE jointly provides one or more of the following:

• activation of TCI states for PDSCH

• mapping of 1 or more than 1 of the activated TCI states to each codepoint of the TCI field in DCI • an additional TCI state which provides the default QCL assumption for PDSCH or the PDSCH layer set or a subset of time/frequency resource corresponding to the 2^nd TCI state indicated in the TCI field in DCI [0110] An example of a MAC CE that jointly provides activation of TCI states for PDSCH, mapping of activated TCI states to codepoints of TCI field in DCI, and the second default QCL assumption for PDSCH is shown in Figure 13. In this example, TCI state IDj,j in the MAC CE denotes the j^th TCI state indicated for the i^th codepoint in the TCI field of DCI. Furthermore, the G field in MAC CE indicates if an additional TCI state is associated with the i^th codepoint in the TCI field of DCI. TCI state ID^ and the Ci field in MAC CE are hence used to provide mapping of activated TCI states to codepoints of TCI field in DCI. The TCI state IDj also provides the activated TCI states for PDSCH. In addition to these, there is an additional bit 'F' in the MAC CE that indicates the presence of a Default TCI State ID. The Default TCI State ID (if present) provides the default QCL assumption for the PDSCH or the PDSCH layer set corresponding to the 2^nd TCI state indicated in the TCI field in DCI. If the bit 'F' is set to 1, then the 2^nd Default TCI State ID is present in the MAC CE. If the bit 'F' is set to 0, then the 2^nd Default TCI State ID is not present in the MAC CE.

[0111] In some embodiments, the default TCI state ID is indicated separately from the TCI States IDs mapped to the codepoints of the TCI field within the same MAC CE. As shown in the example in Figure 13, the Default TCI State ID is indicated in a different octet of the MAC CE than the Octets in which TCI State IDs mapped to the codepoints of the TCI field are indicated.

[0112] In an alternative embodiment, one of the TCI state IDs mapped to one of the codepoints of the TCI field can be used as the default TCI state. In one variant of this alternative embodiment, an N bit codepoint index (e.g., 3 bit codepoint index) can be included as part of the MAC CE to indicate which codepoint in the TCI field is mapped to the default TCI state. In another variant of this alternative embodiment, one of the TCI state IDs mapped to a predefined codepoint (e.g., the 1^st codepoint) of the TCI field can be used as the default TCI state.

[0113] However, indicating the default TCI state ID separately from the TCI States IDs mapped to the codepoints of the TCI field is beneficial as one codepoint does not have to be consumed to indicate the default TCI state. [0114] The above embodiment can be extended to the case where a single PDCCH schedules multi-TRP transmission from more than 2 TRPs. In this case, more than 1 default TCI state may be indicated in the MAC CE. Figure 14 shows an example MAC CE that can be extended to indicate more than one Default TCI state ID. In this example, the Rk bit in the octet containing a default TCI state ID can be used to indicate if there will be an additional default TCI state ID which would serve as an addition default QCL assumption. If R_k is set to 1, then there will be an additional default TCI state ID provided in the next octet of the MAC CE. If R_k is set to 0, then an additional default TCI state ID will not be provided in the next octet of the MAC CE.

[0115] In an alternative embodiment, the second default TCI state is indicated in a MAC CE at the end of the MAC CE table. For example, if there are total N codepoints in the TCI field in DCI, e.g., N=8 if the TCI field contains 3 bits, then the TCI state entry in the MAC CE after the TCI state associated to the N^th codepoint is the second default TCI state. An example is shown in Figure 15, where N=8.

[0116] In another embodiment, the default TCI states for both the first and the second PDSCFIs or PDSCFI layers or time/frequency resources associated to the first and the second TCI states indicated in the TCI of a DCI are signaled in the MAC CE. In that case, the two default TCI states may be signaled in order at the end of the MAC CE.

Embodiment 2

[0117] In this embodiment, embodiment 1 is further extended to also include the CORESET pool index. Since each CORESET pool consisting of one or more CORESETs corresponds to one TRP transmitting a PDCCFI, the CORESET pool index indicated as part of the MAC CE conveys to the UE which TRP the TCI states indicated in the MAC CE applies to. From the CORESET pool index, the UE knows that the activated TCI States and the associated codepoint to TCI state mapping should be applied to a PDCCFI that is carried within one of the CORESETs in the CORESET pool. An example is shown in Figure 16.

[0118] In one embodiment, the MAC CE jointly provides one or more of the following:

• activation of TCI states for PDSCFI • mapping of 1 or more than 1 of the activated TCI states to each codepoint of the TCI field in DCI

• an additional TCI state which provides the default QCL assumption for PDSCH or the PDSCH layer set corresponding to the 2^nd TCI state indicated in the TCI field in DCI

• CORESET pool index

Embodiment 3

[0119] In some further embodiments, the default TCI state indicated in the MAC CE may apply to a list of serving cells or BWPs. Hence, embodiment 1 may be further extended to include such a list of serving cells and/or BWPs. The MAC CE for this embodiment then jointly provides one or more of the following:

• activation of TCI states for PDSCH

• mapping of 1 or more than 1 of the activated TCI states to each codepoint of the TCI field in DCI

• a List of serving cell and/or BWPs for which the other fields of the MAC CE applies. Alternatively, an RRC configured list ID is provided for a list of serving cells and/or BWPs.

Embodiment 4

[0120] In some further embodiments, the default TCI state indicated in the MAC CE may apply to a list of serving cells or BWPs. Hence, embodiment 2 may be further extended to include such a list of serving cells and/or BWPs. The MAC CE for this embodiment then jointly provides one or more of the following:

• activation of TCI states for PDSCH

• mapping of 1 or more than 1 of the activated TCI states to each codepoint of the TCI field in DCI • an additional TCI state which provides the default QCL assumption for PDSCH or the PDSCH layer set corresponding to the 2^nd TCI state indicated in the TCI field in DCI

• CORESET pool index

• List of serving cell and/or BWPs for which the other fields of the MAC CE applies. Alternatively, an RRC configured list ID is provided for a list of serving cells and/or BWPs.

In some embodiments, the UE performs one or more of the following actions:

• UE indicates a threshold timeDurationForQCL as part of UE capability to the gNB

• UE receives configuration from the gNB to receive one or more of single-PDCCH based scheduling of multiple PDSCHs/multiple PDSCH layer sets/multiple subsets of time/frequency resources each associated with a different TCI state

• UE receives scheduling of one or more PDSCHs where the time offset between the reception of the DL DCI and the corresponding PDSCH(s) is smaller than the threshold timeDurationForQCL from the gNB.

• UE receives a first PDSCH or a first PDSCH layer set or a PDSCH on a first subset of time/frequency resource corresponding to the 1st TCI state indicated in the TCI field in DL DCI using a first default TCI state

• receiving a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the 2^nd TCI state indicated in the TCI field in DL DCI using a second default TCI state where the 2^nd default TCI state is provided as part of a MAC CE that activates the TCI states for PDSCH as discussed in the proposed solution.

Embodiment 5

[0121] In an alternative embodiment, both the first and the second default TCI states are indicated as part of the MAC CE providing TCI state activation for PDSCH.

[0122] Figure 17 is a schematic block diagram of a radio access node 1700 according to some embodiments of the present disclosure. Optional features are represented by dashed boxes. The radio access node 1700 may be, for example, a base station 1002 or 1006 or a network node that implements all or part of the functionality of the base station 1002 or gNB described herein. As illustrated, the radio access node 1700 includes a control system 1702 that includes one or more processors 1704 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory 1706, and a network interface 1708. The one or more processors 1704 are also referred to herein as processing circuitry. In addition, the radio access node 1700 may include one or more radio units 1710 that each includes one or more transmitters 1712 and one or more receivers 1714 coupled to one or more antennas 1716. The radio units 1710 may be referred to or be part of radio interface circuitry. In some embodiments, the radio unit(s) 1710 is external to the control system 1702 and connected to the control system 1702 via, e.g., a wired connection (e.g., an optical cable). Flowever, in some other embodiments, the radio unit(s) 1710 and potentially the antenna(s) 1716 are integrated together with the control system 1702. The one or more processors 1704 operate to provide one or more functions of a radio access node 1700 as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 1706 and executed by the one or more processors 1704.

[0123] Figure 18 is a schematic block diagram that illustrates a virtualized embodiment of the radio access node 1700 according to some embodiments of the present disclosure. This discussion is equally applicable to other types of network nodes. Further, other types of network nodes may have similar virtualized architectures. Again, optional features are represented by dashed boxes.

[0124] As used herein, a "virtualized" radio access node is an implementation of the radio access node 1700 in which at least a portion of the functionality of the radio access node 1700 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 radio access node 1700 may include the control system 1702 and/or the one or more radio units 1710, as described above. The control system 1702 may be connected to the radio unit(s) 1710 via, for example, an optical cable or the like. The radio access node 1700 includes one or more processing nodes 1800 coupled to or included as part of a network(s) 1802. If present, the control system 1702 or the radio unit(s) are connected to the processing node(s) 1800 via the network 1802. Each processing node 1800 includes one or more processors 1804 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 1806, and a network interface 1808.

[0125] In this example, functions 1810 of the radio access node 1700 described herein are implemented at the one or more processing nodes 1800 or distributed across the one or more processing nodes 1800 and the control system 1702 and/or the radio unit(s) 1710 in any desired manner. In some particular embodiments, some or all of the functions 1810 of the radio access node 1700 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environ ment(s) hosted by the processing node(s) 1800. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) 1800 and the control system 1702 is used in order to carry out at least some of the desired functions 1810. Notably, in some embodiments, the control system 1702 may not be included, in which case the radio unit(s) 1710 communicate directly with the processing node(s) 1800 via an appropriate network interface(s). [0126] 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 radio access node 1700 or a node (e.g., a processing node 1800) implementing one or more of the functions 1810 of the radio access node 1700 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0127] Figure 19 is a schematic block diagram of the radio access node 1700 according to some other embodiments of the present disclosure. The radio access node 1700 includes one or more modules 1900, each of which is implemented in software. The module(s) 1900 provide the functionality of the radio access node 1700 described herein. This discussion is equally applicable to the processing node 1800 of Figure 18 where the modules 1900 may be implemented at one of the processing nodes 1800 or distributed across multiple processing nodes 1800 and/or distributed across the processing node(s) 1800 and the control system 1702.

[0128] Figure 20 is a schematic block diagram of a wireless communication device 2000 according to some embodiments of the present disclosure. As illustrated, the wireless communication device 2000 includes one or more processors 2002 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 2004, and one or more transceivers 2006 each including one or more transmitters 2008 and one or more receivers 2010 coupled to one or more antennas 2012. The transceiver(s) 2006 includes radio-front end circuitry connected to the antenna(s) 2012 that is configured to condition signals communicated between the antenna(s) 2012 and the processor(s) 2002, as will be appreciated by on of ordinary skill in the art. The processors 2002 are also referred to herein as processing circuitry. The transceivers 2006 are also referred to herein as radio circuitry. In some embodiments, the functionality of the wireless communication device 2000 described above may be fully or partially implemented in software that is, e.g., stored in the memory 2004 and executed by the processor(s) 2002. Note that the wireless communication device 2000 may include additional components not illustrated in Figure 20 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 2000 and/or allowing output of information from the wireless communication device 2000), a power supply (e.g., a battery and associated power circuitry), etc.

[0129] 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 2000 according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0130] Figure 21 is a schematic block diagram of the wireless communication device 2000 according to some other embodiments of the present disclosure. The wireless communication device 2000 includes one or more modules 2100, each of which is implemented in software. The module(s) 2100 provide the functionality of the wireless communication device 2000 described herein.

[0131] With reference to Figure 22, in accordance with an embodiment, a communication system includes a telecommunication network 2200, such as a 3GPP- type cellular network, which comprises an access network 2202, such as a RAN, and a core network 2204. The access network 2202 comprises a plurality of base stations 2206A, 2206B, 2206C, such as Node Bs, eNBs, gNBs, or other types of wireless Access Points (APs), each defining a corresponding coverage area 2208A, 2208B, 2208C. Each base station 2206A, 2206B, 2206C is connectable to the core network 2204 over a wired or wireless connection 2210. A first UE 2212 located in coverage area 2208C is configured to wirelessly connect to, or be paged by, the corresponding base station 2206C. A second UE 2214 in coverage area 2208A is wirelessly connectable to the corresponding base station 2206A. While a plurality of UEs 2212, 2214 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 2206.

[0132] The telecommunication network 2200 is itself connected to a host computer 2216, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server, or as processing resources in a server farm. The host computer 2216 may be under the ownership or control of a service provider or may be operated by the service provider or on behalf of the service provider. Connections 2218 and 2220 between the telecommunication network 2200 and the host computer 2216 may extend directly from the core network 2204 to the host computer 2216 or may go via an optional intermediate network 2222. The intermediate network 2222 may be one of, or a combination of more than one of, a public, private, or hosted network; the intermediate network 2222, if any, may be a backbone network or the Internet; in particular, the intermediate network 2222 may comprise two or more sub-networks (not shown).

[0133] The communication system of Figure 22 as a whole enables connectivity between the connected UEs 2212, 2214 and the host computer 2216. The connectivity may be described as an Over-the-Top (OTT) connection 2224. The host computer 2216 and the connected UEs 2212, 2214 are configured to communicate data and/or signaling via the OTT connection 2224, using the access network 2202, the core network 2204, any intermediate network 2222, and possible further infrastructure (not shown) as intermediaries. The OTT connection 2224 may be transparent in the sense that the participating communication devices through which the OTT connection 2224 passes are unaware of routing of uplink and downlink communications. For example, the base station 2206 may not or need not be informed about the past routing of an incoming downlink communication with data originating from the host computer 2216 to be forwarded (e.g., handed over) to a connected UE 2212. Similarly, the base station 2206 need not be aware of the future routing of an outgoing uplink communication originating from the UE 2212 towards the host computer 2216.

[0134] Example implementations, in accordance with an embodiment, of the UE, base station, and host computer discussed in the preceding paragraphs will now be described with reference to Figure 23. In a communication system 2300, a host computer 2302 comprises hardware 2304 including a communication interface 2306 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 2300. The host computer 2302 further comprises processing circuitry 2308, which may have storage and/or processing capabilities. In particular, the processing circuitry 2308 may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions. The host computer 2302 further comprises software 2310, which is stored in or accessible by the host computer 2302 and executable by the processing circuitry 2308. The software 2310 includes a host application 2312. The host application 2312 may be operable to provide a service to a remote user, such as a UE 2314 connecting via an OTT connection 2316 terminating at the UE 2314 and the host computer 2302. In providing the service to the remote user, the host application 2312 may provide user data which is transmitted using the OTT connection 2316. [0135] The communication system 2300 further includes a base station 2318 provided in a telecommunication system and comprising hardware 2320 enabling it to communicate with the host computer 2302 and with the UE 2314. The hardware 2320 may include a communication interface 2322 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 2300, as well as a radio interface 2324 for setting up and maintaining at least a wireless connection 2326 with the UE 2314 located in a coverage area (not shown in Figure 23) served by the base station 2318. The communication interface 2322 may be configured to facilitate a connection 2328 to the host computer 2302. The connection 2328 may be direct or it may pass through a core network (not shown in Figure 23) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 2320 of the base station 2318 further includes processing circuitry 2330, which may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions. The base station 2318 further has software 2332 stored internally or accessible via an external connection.

[0136] The communication system 2300 further includes the UE 2314 already referred to. The UE's 2314 hardware 2334 may include a radio interface 2336 configured to set up and maintain a wireless connection 2326 with a base station serving a coverage area in which the UE 2314 is currently located. The hardware 2334 of the UE 2314 further includes processing circuitry 2338, which may comprise one or more programmable processors, ASICs, FPGAs, or combinations of these (not shown) adapted to execute instructions. The UE 2314 further comprises software 2340, which is stored in or accessible by the UE 2314 and executable by the processing circuitry 2338. The software 2340 includes a client application 2342. The client application 2342 may be operable to provide a service to a human or non-human user via the UE 2314, with the support of the host computer 2302. In the host computer 2302, the executing host application 2312 may communicate with the executing client application 2342 via the OTT connection 2316 terminating at the UE 2314 and the host computer 2302. In providing the service to the user, the client application 2342 may receive request data from the host application 2312 and provide user data in response to the request data. The OTT connection 2316 may transfer both the request data and the user data. The client application 2342 may interact with the user to generate the user data that it provides.

[0137] It is noted that the host computer 2302, the base station 2318, and the UE 2314 illustrated in Figure 23 may be similar or identical to the host computer 2216, one of the base stations 2206A, 2206B, 2206C, and one of the UEs 2212, 2214 of Figure 22, respectively. This is to say, the inner workings of these entities may be as shown in Figure 23 and independently, the surrounding network topology may be that of Figure 22.

[0138] In Figure 23, the OTT connection 2316 has been drawn abstractly to illustrate the communication between the host computer 2302 and the UE 2314 via the base station 2318 without explicit reference to any intermediary devices and the precise routing of messages via these devices. The network infrastructure may determine the routing, which may be configured to hide from the UE 2314 or from the service provider operating the host computer 2302, or both. While the OTT connection 2316 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

[0139] The wireless connection 2326 between the UE 2314 and the base station 2318 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 2314 using the OTT connection 2316, in which the wireless connection 2326 forms the last segment. More precisely, the teachings of these embodiments may improve the e.g., data rate, latency, power consumption, etc. and thereby provide benefits such as e.g., reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc.

[0140] A measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 2316 between the host computer 2302 and the UE 2314, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 2316 may be implemented in the software 2310 and the hardware 2304 of the host computer 2302 or in the software 2340 and the hardware 2334 of the UE 2314, or both. In some embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 2316 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which the software 2310, 2340 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 2316 may include message format, retransmission settings, preferred routing, etc.; the reconfiguring need not affect the base station 2318, and it may be unknown or imperceptible to the base station 2318. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer 2302's measurements of throughput, propagation times, latency, and the like. The measurements may be implemented in that the software 2310 and 2340 causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection 2316 while it monitors propagation times, errors, etc.

[0141] Figure 24 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 22 and 23. For simplicity of the present disclosure, only drawing references to Figure 24 will be included in this section. In step 2400, the host computer provides user data. In sub-step 2402 (which may be optional) of step 2400, the host computer provides the user data by executing a host application. In step 2404, the host computer initiates a transmission carrying the user data to the UE. In step 2406 (which may be optional), the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 2408 (which may also be optional), the UE executes a client application associated with the host application executed by the host computer.

[0142] Figure 25 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 22 and 23. For simplicity of the present disclosure, only drawing references to Figure 25 will be included in this section. In step 2500 of the method, the host computer provides user data. In an optional sub-step (not shown) the host computer provides the user data by executing a host application. In step 2502, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In step 2504 (which may be optional), the UE receives the user data carried in the transmission.

[0143] Figure 26 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 22 and 23. For simplicity of the present disclosure, only drawing references to Figure 26 will be included in this section. In step 2600 (which may be optional), the UE receives input data provided by the host computer. Additionally or alternatively, in step 2602, the UE provides user data. In sub-step 2604 (which may be optional) of step 2600, the UE provides the user data by executing a client application. In sub-step 2606 (which may be optional) of step 2602, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in sub-step 2608 (which may be optional), transmission of the user data to the host computer. In step 2610 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.

[0144] Figure 27 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station, and a UE which may be those described with reference to Figures 22 and 23. For simplicity of the present disclosure, only drawing references to Figure 27 will be included in this section. In step 2700 (which may be optional), in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE.

In step 2702 (which may be optional), the base station initiates transmission of the received user data to the host computer. In step 2704 (which may be optional), the host computer receives the user data carried in the transmission initiated by the base station.

[0145] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.

[0146] While processes in the figures may show a particular order of operations performed by certain embodiments of the present disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform the operations in a different order, combine certain operations, overlap certain operations, etc.).

[0147] Embodiments [0148] Group A Embodiments

[0149] Embodiment 1: A method performed by a wireless device for receiving Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the method comprising one or more of: transmitting an indication of a time duration threshold; receiving a configuration to receive at least one of the following: i. single-PDCCH based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and ii. multi-PDCCH based scheduling of multiple PDSCHs; receiving a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the 1st TCI state indicated in the TCI field in DL DCI using a first default TCI state; and receiving a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the 2^nd TCI state indicated in the TCI field in DL DCI using a second default TCI state provided as part of a MAC CE that activates the TCI states for PDSCH.

[0150] Embodiment 2: The method of the previous embodiments wherein the time duration threshold comprises timeDurationForQCL.

[0151] Embodiment 3: The method of any of the previous embodiments wherein the MAC CE jointly provides the additional QCL assumption along with one or more of the following: activation of TCI states for PDSCH; mapping of one or more activated TCI states per each codepoint of the TCI field in the DL DCI; and a CORESET pool index. [0152] Embodiment 4: The method of the previous embodiments wherein the additional QCL assumption is an additional TCI state ID provided in the MAC CE. [0153] Embodiment 5: The method of the previous embodiments wherein the additional TCI state ID is indicated separately from the TCI States IDs mapped to the codepoints of the TCI field within the MAC CE.

[0154] Embodiment 6: The method of the previous embodiments wherein the additional TCI state ID is indicated to be one of the TCI States IDs mapped to one of the codepoints of the TCI field within the MAC CE.

[0155] Embodiment 7: The method of the previous embodiments wherein a flag field in the MAC CE indicates if the additional TCI state ID for QCL assumption is present or not in the MAC CE.

[0156] Embodiment 8: The method of the previous embodiments wherein the first default TCI state is the TCI state of the CORESET associated with a monitored search space with the lowest CORESET-ID in the latest slot.

[0157] Embodiment 9: The method of the previous embodiments wherein the first default TCI state is signaled in the MAC CE together with the second default TCI state. [0158] Embodiment 10: The method of the previous embodiments wherein the first and/or the second default TCI state is signaled at the end of the MAC CE entries.

[0159] Embodiment 11: The method of any of the previous embodiments, further comprising: providing user data; and forwarding the user data to a host computer via the transmission to the base station.

[0160] Group B Embodiments

[0161] Embodiment 12: A method performed by a base station for indicating Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the method comprising one or more of: receiving an indication of a time duration threshold; configuring a wireless device to receive at least one of the following: i. single-PDCCH based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and ii. multi-PDCCH based scheduling of multiple PDSCHs; scheduling one or more PDSCHs with time offset between the reception of the DL DCI and the corresponding PDSCH or PDSCH layer sets is smaller than the time duration threshold; transmitting a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the 1st TCI state indicated in the TCI field in DL DCI using a first default TCI state; and transmitting a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the 2^nd TCI state indicated in the TCI field in DL DCI using a second default TCI state provided as part of a MAC CE that activates the TCI states for PDSCH. [0162] Embodiment 13: The method of the previous embodiments wherein the time duration threshold comprises timeDurationForQCL.

[0163] Embodiment 14: The method of any of the previous 2 embodiments wherein the MAC CE jointly provides the additional QCL assumption along with one or more of the following: activation of TCI states for PDSCH; mapping of one or more activated TCI states per each codepoint of the TCI field in the DL DCI; and a CORESET pool index. [0164] Embodiment 15: The method of the previous embodiments wherein the additional QCL assumption is an additional TCI state ID provided in the MAC CE.

[0165] Embodiment 16: The method of the previous embodiments wherein the additional TCI state ID is indicated separately from the TCI States IDs mapped to the codepoints of the TCI field within the MAC CE.

[0166] Embodiment 17: The method of the previous embodiments wherein the additional TCI state ID is indicated to be one of the TCI States IDs mapped to one of the codepoints of the TCI field within the MAC CE.

[0167] Embodiment 18: The method of the previous embodiments wherein a flag field in the MAC CE indicates if the additional TCI state ID for QCL assumption is present or not in the MAC CE.

[0168] Embodiment 19: The method of the previous embodiments wherein the first default TCI state is the TCI state of the CORESET associated with a monitored search space with the lowest CORESET-ID in the latest slot.

[0169] Embodiment 20: The method of the previous embodiments wherein the first default TCI state is signaled in the MAC CE together with the second default TCI state. [0170] Embodiment 21: The method of the previous embodiments wherein the first and/or the second default TCI state is signaled at the end of the MAC CE entries.

[0171] Embodiment 22: The method of any of the previous embodiments, further comprising: obtaining user data; and forwarding the user data to a host computer or a wireless device.

[0172] Group C Embodiments [0173] Embodiment 23: A wireless device for receiving Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the wireless device comprising: processing circuitry configured to perform any of the steps of any of the Group A embodiments; and power supply circuitry configured to supply power to the wireless device.

[0174] Embodiment 24: A base station for indicating Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the base station comprising: processing circuitry configured to perform any of the steps of any of the Group B embodiments; and power supply circuitry configured to supply power to the base station.

[0175] Embodiment 25: A User Equipment, UE, for receiving Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE. [0176] Embodiment 26: A communication system including a host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward the user data to a cellular network for transmission to a User Equipment, UE; wherein the cellular network comprises a base station having a radio interface and processing circuitry, the base station's processing circuitry configured to perform any of the steps of any of the Group B embodiments.

[0177] Embodiment 27: The communication system of the previous embodiment further including the base station. [0178] Embodiment 28: The communication system of the previous 2 embodiments, further including the UE, wherein the UE is configured to communicate with the base station.

[0179] Embodiment 29: The communication system of the previous 3 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the UE comprises processing circuitry configured to execute a client application associated with the host application.

[0180] Embodiment 30: A method implemented in a communication system including a host computer, a base station, and a User Equipment, UE, the method comprising: at the host computer, providing user data; and at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the base station performs any of the steps of any of the Group B embodiments.

[0181] Embodiment 31: The method of the previous embodiment, further comprising, at the base station, transmitting the user data.

[0182] Embodiment 32: The method of the previous 2 embodiments, wherein the user data is provided at the host computer by executing a host application, the method further comprising, at the UE, executing a client application associated with the host application.

[0183] Embodiment 33: A User Equipment, UE, configured to communicate with a base station, the UE comprising a radio interface and processing circuitry configured to perform the method of the previous 3 embodiments.

[0184] Embodiment 34: A communication system including a host computer comprising: processing circuitry configured to provide user data; and a communication interface configured to forward user data to a cellular network for transmission to a User Equipment, UE; wherein the UE comprises a radio interface and processing circuitry, the UE's components configured to perform any of the steps of any of the Group A embodiments.

[0185] Embodiment 35: The communication system of the previous embodiment, wherein the cellular network further includes a base station configured to communicate with the UE.

[0186] Embodiment 36: The communication system of the previous 2 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and the UE's processing circuitry is configured to execute a client application associated with the host application.

[0187] Embodiment 37: A method implemented in a communication system including a host computer, a base station, and a User Equipment, UE, the method comprising: at the host computer, providing user data; and at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the UE performs any of the steps of any of the Group A embodiments. [0188] Embodiment 38: The method of the previous embodiment, further comprising at the UE, receiving the user data from the base station.

[0189] Embodiment 39: A communication system including a host computer comprising: communication interface configured to receive user data originating from a transmission from a User Equipment, UE, to a base station; wherein the UE comprises a radio interface and processing circuitry, the UE's processing circuitry configured to perform any of the steps of any of the Group A embodiments.

[0190] Embodiment 40: The communication system of the previous embodiment, further including the UE.

[0191] Embodiment 41: The communication system of the previous 2 embodiments, further including the base station, wherein the base station comprises a radio interface configured to communicate with the UE and a communication interface configured to forward to the host computer the user data carried by a transmission from the UE to the base station.

[0192] Embodiment 42: The communication system of the previous 3 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application; and the UE's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data.

[0193] Embodiment 43: The communication system of the previous 4 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application, thereby providing request data; and the UE's processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data in response to the request data.

[0194] Embodiment 44: A method implemented in a communication system including a host computer, a base station, and a User Equipment, UE, the method comprising: at the host computer, receiving user data transmitted to the base station from the UE, wherein the UE performs any of the steps of any of the Group A embodiments.

[0195] Embodiment 45: The method of the previous embodiment, further comprising, at the UE, providing the user data to the base station.

[0196] Embodiment 46: The method of the previous 2 embodiments, further comprising: at the UE, executing a client application, thereby providing the user data to be transmitted; and at the host computer, executing a host application associated with the client application.

[0197] Embodiment 47: The method of the previous 3 embodiments, further comprising: at the UE, executing a client application; and at the UE, receiving input data to the client application, the input data being provided at the host computer by executing a host application associated with the client application; wherein the user data to be transmitted is provided by the client application in response to the input data.

[0198] Embodiment 48: A communication system including a host computer comprising a communication interface configured to receive user data originating from a transmission from a User Equipment, UE, to a base station, wherein the base station comprises a radio interface and processing circuitry, the base station's processing circuitry configured to perform any of the steps of any of the Group B embodiments. [0199] Embodiment 49: The communication system of the previous embodiment further including the base station.

[0200] Embodiment 50: The communication system of the previous 2 embodiments, further including the UE, wherein the UE is configured to communicate with the base station.

[0201] Embodiment 51: The communication system of the previous 3 embodiments, wherein: the processing circuitry of the host computer is configured to execute a host application; and the UE is configured to execute a client application associated with the host application, thereby providing the user data to be received by the host computer. [0202] Embodiment 52: A method implemented in a communication system including a host computer, a base station, and a User Equipment, UE, the method comprising: at the host computer, receiving, from the base station, user data originating from a transmission which the base station has received from the UE, wherein the UE performs any of the steps of any of the Group A embodiments. [0203] Embodiment 53: The method of the previous embodiment, further comprising at the base station, receiving the user data from the UE.

[0204] Embodiment 54: The method of the previous 2 embodiments, further comprising at the base station, initiating a transmission of the received user data to the host computer.

[0205] At least some of the following abbreviations may be used in this disclosure. If there is an inconsistency between abbreviations, preference should be given to how it is used above. If listed multiple times below, the first listing should be preferred over any subsequent listing(s).

• 3GPP Third Generation Partnership Project

• 5G Fifth Generation

• 5GC Fifth Generation Core

• 5GS Fifth Generation System

• AF Application Function

• AMF Access and Mobility Function

• AN Access Network

• AP Access Point

• ASIC Application Specific Integrated Circuit

• AUSF Authentication Server Function

• BW Bandwidth

• BWP Bandwidth part

• CDM Code Division Multiplexing

• CE Control Element

• CO RESET Control Resource Set

• CPU Central Processing Unit

• CSI Channel State Information

• CSI-IM Channel State Information Interference Measurement

• CSI-RS Channel State Information Reference Signal

• DCI Downlink control information

• DL Downlink

• DMRS Dedicated demodulation reference signals

• DN Data Network

• DRX Discontinued Receiving DSP Digital Signal Processor eMBB Enhanced Mobile Broadband eNB Enhanced or Evolved Node B

EPS Evolved Packet System

E-UTRA Evolved Universal Terrestrial Radio Access

FFS For Further Study

FPGA Field Programmable Gate Array

FR1 Frequency Range 1

FR2 Frequency Range 2 gNB New Radio Base Station gNB-DU New Radio Base Station Distributed Unit

HSS Flome Subscriber Server

ID Index

IE Information element

IoT Internet of Things

IP Internet Protocol

LCID Logical Channel ID

LTE Long Term Evolution

MAC Medium Access Control

MIMO Multiple Input Multiple Output

MME Mobility Management Entity

MTC Machine Type Communication

MU-MIMO Multi-User MIMO

NC-JT Non-Coherent Joint Transmission

NEF Network Exposure Function

NF Network Function

NR New Radio

NRF Network Function Repository Function

NSSF Network Slice Selection Function

OCC Orthogonal Cover Code

OCT Octet

OFDM Orthogonal Frequency Domain Multiplexing

OTT Over-the-Top • PC Personal Computer

• PCF Policy Control Function

• PDCCH Physical downlink control channel

• PDCH Physical data Channel

• PDSCH Physical downlink shared channel

• PDU Packet Data Unit

• P-GW Packet Data Network Gateway

• PUCCH Physical uplink control channel

• PUSCH Physical uplink shared channel

• QCL Quasi co-location

• QoS Quality of Service

• RAM Random Access Memory

• RAN Radio Access Network

• RB Resource Block

• RE Resource element

• Rel Release

• ROM Read Only Memory

• RRC Radio Resource Control

• RRH Remote Radio Head

• RS Reference signal

• RTT Round Trip Time

• Rx Receive

• SCEF Service Capability Exposure Function

• SINR Signal to Interference and Noise Ratio

• SMF Session Management Function

• SP Semi-Persistent

• SRS Sounding Reference Signal

• TB Transport Block

• TCI transmission Configuration Indicator

• TRP Transmission and Reception Point (or Panel)

• TRS Tracking Reference Signal

• Tx Transmit • UDM Unified Data Management

• UE User Equipment

• UL Uplink

• UPF User Plane Function

• URLLC Ultra-Reliable Low Latency Communications

• ZP Zero Power

[0206] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein.

Claims

1. A method performed by a wireless device for receiving Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the method comprising one or more of: transmitting (1100) an indication of a time duration threshold; receiving (1102) a first and/or a second default TCI states in a MAC CE that activates TCI states for PDSCH; receiving (1104) a configuration to receive at least one of the following: single-DCI based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-DCI based scheduling of multiple PDSCHs; receiving (1106) a DL DCI and a first PDSCH, a first PDSCH layer set, or a PDSCH on a first subset of time/frequency resources corresponding to a first TCI state indicated in a TCI field in the DL DCI using a third default TCI state; and receiving (1108) a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to a second TCI state indicated in the TCI field in the DL DCI using a fourth default TCI state.

2. The method of claim 1 wherein the third and the fourth default TCI states are respectively the first default TCI state and the second default TCI state provided in the MAC CE.

3. The method of any of claims 1 to 2 wherein the third and the fourth default TCI states are predefined default TCI states.

4. The method of any of claims 1 to 3 wherein the first default TCI state is same as or different from the second default TCI state.

5. The method of any of claims 1 to 4 wherein the default TCI states are used only when time duration between the DL DCI and the corresponding PDSCH(s) is below the time duration threshold.

6. The method of any of claims 1 to 5 wherein the time duration threshold comprises a higher layer parameter timeDurationForQCL.

7. The method of any of claims 1 to 6 wherein the MAC CE jointly provides the additional QCL assumption along with one or more of the following: activation of TCI states for PDSCH; mapping of one or more activated TCI states per each codepoint of the TCI field in the DL DCI; and a Control resource Set, CORESET, pool index.

8. The method of any of claims 1 to 7 wherein the first or the second default TCI state ID provided by the MAC CE is an additional TCI state ID provided in the MAC CE.

9. The method of any of claims 1 to 8 wherein the additional TCI state ID is indicated separately from the TCI States IDs mapped to the codepoints of the TCI field within the MAC CE.

10. The method of any of claims 1 to 9 wherein the additional TCI state ID is indicated to be one of the TCI States IDs mapped to one of the codepoints of the TCI field within the MAC CE.

11. The method of any of claims 1 to 10 wherein a flag field in the MAC CE indicates if the additional TCI state ID is present or not in the MAC CE.

12. The method of any of claims 1 toll wherein the third default TCI state is the TCI state of a CORESET associated with a monitored search space with the lowest CORESET-ID in the latest slot.

13. The method of any of claims 1 to 12 wherein the first default TCI state is signaled in the MAC CE together with the second default TCI state.

14. The method of any of claims 1 to 13 wherein the first and/or the second default TCI state is signaled at the end of the MAC CE entries.

15. The method of any of claims 1 to 14 wherein the wireless device operates in a New Radio, NR, telecommunications network.

16. A method performed by a base station for indicating Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the method comprising one or more of: receiving (1200) an indication of a time duration threshold from a wireless device; configuring (1202) the wireless device to receive at least one of the following: single-DCI based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-DCI based scheduling of multiple PDSCHs; transmitting (1204) a first and/or a second default TCI states in a MAC CE that activates TCI states for PDSCH. scheduling (1206) one or more PDSCHs with a DL DCI wherein the time offset between transmitting the DL DCI and the corresponding PDSCH or PDSCH layer sets is smaller than the time duration threshold; transmitting (1208) the DL DCI and a first PDSCH, a first PDSCH layer set, or a PDSCH on a first subset of time/frequency resources corresponding to the first TCI state indicated in a TCI field in the DL DCI using a third default TCI state; and transmitting (1210) a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the second TCI state indicated in the TCI field in the DL DCI using a fourth default TCI state.

17. The method of claim 16 wherein the third and the fourth default TCI states are respectively the first default TCI state and the second default TCI state provided in the MAC CE.

18. The method of any of claims 16 to 17 wherein the third and the fourth default TCI states are predefined default TCI states.

19. The method of any of claims 16 to 18 wherein the first default TCI state is same as or different from the second default TCI state.

20. The method of claim 16 wherein the time duration threshold comprises a higher layer parameter timeDurationForQCL.

21. The method of any of claims 16 to 20 wherein the MAC CE jointly provides the additional QCL assumption along with one or more of the following: activation of TCI states for PDSCH; mapping of one or more activated TCI states per each codepoint of the TCI field in the DL DCI; and a CONTROL RESOURCE Set, CORESET, pool index.

22. The method of any of claims 16 to 21 wherein the first or the second default TCI state ID provided by the MAC CE is an additional TCI state ID provided in the MAC CE.

23. The method of any of claims 16 to 22 wherein the additional TCI state ID is indicated separately from the TCI States IDs mapped to the codepoints of the TCI field within the MAC CE.

24. The method of any of claims 16 to 23 wherein the additional TCI state ID is indicated to be one of the TCI States IDs mapped to one of the codepoints of the TCI field within the MAC CE.

25. The method of any of claims 16 to 24 wherein a flag field in the MAC CE indicates if the additional TCI state ID is present or not in the MAC CE.

26. The method of any of claims 16 to 25 wherein the third default TCI state is the TCI state of a CORESET associated with a monitored search space with the lowest CORESET-ID in the latest slot.

27. The method of any of claims 16 to 26 wherein the first default TCI state is signaled in the MAC CE together with the second default TCI state.

28. The method of any of claims 16 to 27 wherein the first and/or the second default TCI state is signaled at the end of the MAC CE entries.

29. A wireless device (2000) for receiving Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the wireless device (2000) comprising: one or more processors (2002); and memory (2004) storing instructions executable by the one or more processors, whereby the wireless device (2000) is operable to perform one or more of: transmit an indication of a time duration threshold; receive a first and/or a second default TCI states in a MAC CE that activates TCI states for PDSCH; receive a configuration to receive at least one of the following: single-DCI based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-DCI based scheduling of multiple PDSCHs; receive a DL DCI and a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the first TCI state indicated in a TCI field in the DL DCI using a third default TCI state; and receive a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the second TCI state indicated in the TCI field in the DL DCI using a fourth default TCI state.

30. The wireless device (2000) of claim 29 wherein the instructions further cause the wireless device (2000) to perform the method of any one of claims 2 to 15.

31. A base station (1700) for indicating Transmission Configuration Indication, TCI, state activation for Physical Downlink Data Channel, PDSCH, via Medium Access Control, MAC, Control Element, CE, the base station (1700) comprising: one or more processors (1704); and memory (1706) comprising instructions to cause the base station (1700) to perform one or more of: receive an indication of a time duration threshold from a wireless device; configure the wireless device to receive at least one of the following: single-DCI based scheduling of either multiple PDSCHs each associated with a different TCI state; a PDSCH with multiple PDSCH layer sets each associated with a different TCI state; or a PDSCH with multiple subsets of time/frequency resources each associated with a different TCI state; and multi-DCI based scheduling of multiple PDSCHs; transmit a first and/or a second default TCI states in a MAC CE that activates TCI states for PDSCH. schedule one or more PDSCHs with a DL DCI wherein the time offset between the reception of the DL DCI and the corresponding PDSCH or PDSCH layer sets is smaller than the time duration threshold; transmit the DL DCI and a first PDSCH; a first PDSCH layer set; or a PDSCH on a first subset of time/frequency resources corresponding to the first TCI state indicated in the TCI field in DL DCI using a third default TCI state; and transmit a second PDSCH or a second PDSCH layer set or a PDSCH on a second subset of time/frequency resource corresponding to the second TCI state indicated in the TCI field in DL DCI using a fourth default TCI state.

32. The base station (1700) of claim 31 wherein the instructions further cause the base station (1700) to perform the method of any one of claims 17 to 30.