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US-20260129640-A1 - SYSTEMS AND METHODS FOR TCI STATE ACTIVATION AND CODEPOINT TO TCI STATE MAPPING

US20260129640A1US 20260129640 A1US20260129640 A1US 20260129640A1US-20260129640-A1

Abstract

Systems and methods for TCI state activation and codepoint to TCI state mapping are provided. A method performed by a wireless device for activating TCI states includes one or more of: being configured to monitor a plurality of DCI formats with the TCI field for PDSCH reception; receiving a single MAC CE to activate TCI states and map activated TCI states to the TCI field codepoints of the DCI formats; and receiving separate MAC CEs to activate TCI states and map activated TCI states to the TCI field codepoints of each of the plurality of DCI formats. As such, TCI states for downlink scheduling can be more flexibly chosen for each DCI format by using separate MAC CEs. Additionally, default TCI state definitions might be provided when state activation and state to TCI field codepoint mapping to multiple DCI formats are provided by either a single or different MAC CEs.

Inventors

  • Siva Muruganathan
  • Helka-Liina Määttänen
  • Shiwei Gao

Assignees

  • TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Dates

Publication Date
20260507
Application Date
20251230

Claims (13)

  1. 1 . A method performed by a wireless device for activating Transmission Configuration Indicator, TCI, states, the method comprising: being configured to monitor a plurality of Downlink Control Information, DCI, formats each with a TCI field for Physical Downlink Shared Channel, PDSCH, reception, wherein the TCI field of the plurality of DCI formats is configured with different sizes; receiving a single TCI state activation command to activate a plurality of TCI states and map the activated TCI states to a set of codepoints of the TCI field for the plurality of DCI formats, wherein at least one codepoints within the set of codepoints is mapped to two activated TCI states; and receiving separate TCI state activation commands to activate the plurality of TCI states and map the activated TCI states to the set of codepoints of the TCI field for each of the plurality of DCI formats, wherein the at least one of the codepoints within the set of codepoints is mapped to the two activated TCI states.
  2. 2 . The method of claim 1 wherein the single TCI state activation command is a Medium Access Control, MAC, Control Element, CE.
  3. 3 . The method of claim 1 wherein one or more of the plurality of DCI formats are DCI formats 1_1 and/or 1_2.
  4. 4 . The method of claim 1 , wherein receiving the single TCI state activation command to activate the plurality of TCI states and map the activated TCI states to the set of codepoints of the TCI field for the plurality of DCI formats comprises using a subset of the mappings for DCI formats having a TCI field with a smaller number of codepoints than the set of codepoints provided by the single TCI state activation command.
  5. 5 . The method of claim 1 wherein, when a number of codepoints S of the TCI field of a DCI is smaller than a maximum number of codepoints provided in the single TCI state activation command, the S codepoints are mapped to first S codepoints in the single TCI state activation command.
  6. 6 . The method of claim 1 wherein, when the single TCI state activation command is used for TCI state activation/deactivation for both DCI formats 1_1 and 1_2, default TCI states are TCI states corresponding to a lowest codepoint among TCI codepoints contained in the single TCI state activation command, containing two different TCI states.
  7. 7 . The method of claim 5 , where S is determined from the higher layer parameter tci-PresentInDCI-ForDCI-Format1-2 as S=2 K where K can take on one value out of 1, 2, or 3 as configured by tci-PresentInDCI-ForDCI-Format1-2.
  8. 8 . The method of claim 2 , wherein using a single MAC CE to activate the plurality of TCI states and map the activated TCI states to the set of codepoints of the TCI field for the plurality of DCI formats includes: receiving TCI state mappings to a larger number of codepoints than the number of the codepoints of the TCI field in any of the plurality of DCI formats in the MAC CE; using mappings of a first subset of the TCI field codepoints in the MAC CE to the TCI field codepoints of a first DCI format, and using the mappings of a second subset of the TCI field codepoints in the MAC CE to the TCI field codepoints of a second DCI format.
  9. 9 . The method of claim 1 , wherein using the MAC CE to activate the TCI states and map the activated TCI states to the TCI field codepoints of the plurality of DCI formats includes using a field in the MAC CE to indicate which DCI format among the plurality of DCI formats to which the TCI codepoint mapping applies to.
  10. 10 . The method of claim 1 , wherein receiving the separate TCI state activation commands to activate the TCI states and map the activated TCI states to the TCI field codepoints for the plurality of DCI formats comprises receiving one MAC CE activation command for each of the plurality of DCI formats to activate the plurality of TCI states and map the activated TCI states to the set of codepoints of the TCI field of the DCI format.
  11. 11 . The method of claim 1 , wherein the default TCI state is defined as the TCI states corresponding to the lowest codepoint among the TCI codepoints contained in the MAC CE containing two different TCI states.
  12. 12 . The method of claim 1 , wherein the default TCI state is defined as the TCI states corresponding to the lowest codepoint among the TCI codepoints contained in one of the separate MAC CEs containing two different TCI states.
  13. 13 . A method performed by a base station for activating Transmission Configuration Indicator, TCI, states, the method comprising: configuring a wireless device to monitor a plurality of Downlink Control Information, DCI, formats each with a TCI field for Physical Downlink Shared Channel, PDSCH, reception, wherein the TCI field of the plurality of DCI formats is configured with different sizes; transmitting, to the wireless device, a single TCI activation command to activate the TCI states and map the activated TCI states to TCI field codepoints for the plurality of DCI formats; and transmitting, to the wireless device, separate TCI activation commands to activate the TCI states and map the activated TCI states to the TCI field codepoints for each of the plurality of DCI formats.

Description

RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 17/917,357, filed Oct. 6, 2022, which is a 35 U.S.C. § 371 national phase filing of International Application No. PCT/IB2021/052979, filed Apr. 9, 2021, which claims the benefit of provisional patent application Ser. No. 63/007,746, filed Apr. 9, 2020, the disclosures of which are hereby incorporated herein by reference in their entireties. TECHNICAL FIELD This closure relates to Transmission Configuration Indicator (TCI) state activation and codepoint to TCI state mapping. BACKGROUND 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. 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 discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) in the uplink (i.e., from User Equipment (UE) to New Radio Base Station (gNB)). In the time domain, NR downlink and uplink physical resources are organized into equally-sized subframes of 1 ms each. A subframe is further divided into multiple slots of equal duration. The slot length depends on subcarrier spacing. For subcarrier spacing of Δf=15 kHz, there is only one slot per subframe, and each slot always consists of 14 OFDM symbols, irrespectively of the subcarrier spacing. FIG. 1 illustrates NR time-domain structure with 15 kHz subcarrier spacing, according to some embodiments. Typical data scheduling in NR are per slot basis, an example is shown in FIG. 1 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). Different subcarrier spacing values are supported in NR. The supported subcarrier spacing values (also referred to as different numerologies) are given by Δf=(15×2α) kHz where α is a non-negative integer. Δf=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. NumerologySlot lengthRB BW15 kHz1ms180kHz30 kHz0.5ms360kHz60 kHz0.25ms720kHz120kHz125μs1.44MHz240kHz62.5μs2.88MHz 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 (CRB) 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 Resource Block (PRB) are numbered from 0 to N−1 within a BWP (but the 0:th PRB may thus be the K:th CRB where K>0). The basic NR physical time-frequency resource grid is illustrated in FIG. 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). 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. 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. There currently exist certain challenges. For DCI format 1_1, when the TCI field is enabled, the TCI field in DCI format 1_1 is always 3 bits (i.e., 8 codepoints). So, the number of TCI field codepoints in DCI format 1_1 does not change when TCI field is enabled in different CORESETs. Therefore, improvements for TCI state activation and codepoint to TCI state mapping are needed. SUMMARY Systems and methods for Transmission Configuration Indicator (TCI) state activation and codepoint to TCI state mapping are provided. In some embodiments, a method performed by a wireless device for activating TCI states includes one or more of: being configured to monitor a plurality of Downlink Control Information (DCI) formats with the TCI field