TCI State Updating for Multi-TRP PDCCH Across Expanded CORESETs
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Solution Overview
Problem
The existing MAC CE for TCI state indication in NR Rel-15 is insufficient for multi-PDCCH based multi-TRP scenarios due to the limited number of CORESETs per serving cell, which cannot accommodate the increased maximum number of CORESETs per 'PDCCH-config' beyond 16.
Innovation Solution
Proposed solutions include reinterpreting the CORESET ID field in the Rel-15 MAC CE when CORESET groups are configured, limiting the maximum number of CORESETs per serving cell via UE capability signaling, or defining a new MAC CE with a 5-bit CORESET ID field to support up to 32 CORESETs per serving cell, and using a higher layer index to form CORESET groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the maximum number of CORESETs per serving cell is increased beyond 16 to support multi-PDCCH based multi-TRP scenarios, then the adaptability and versatility of the system is improved, but the device complexity and difficulty of detecting and measuring increase due to the insufficient existing MAC CE structure
Solution Approach 1:
The patent divides the CORESET indication space into multiple segments by introducing a multi-stage indication mechanism. The first stage uses a coarse indication field to identify a group of CORESETs, and the second stage uses a fine indication field to identify the specific CORESET within the group. This segmentation allows the system to support a larger number of CORESETs (beyond 16) while keeping each individual indication field manageable in size, thus resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
The patent transitions from a one-dimensional indication approach (single field indicating one CORESET) to a two-dimensional indication approach (first indication field + second indication field). This dimensional change enables the system to address more CORESETs by combining multiple indication stages, effectively expanding the indication capacity without proportionally increasing the complexity of each individual indication element.
2Adaptability or versatility
If a new MAC CE with 5-bit CORESET ID field is defined to support up to 32 CORESETs, then the adaptability is improved, but the ease of manufacture and compatibility with legacy systems deteriorates
Solution Approach 1:
The patent designs the MAC CE structure to serve multiple functions: it can operate in a legacy mode for UEs that support only up to 16 CORESETs, and in an enhanced mode for UEs that support up to 32 CORESETs. The multi-stage indication mechanism allows the same MAC CE to function differently based on UE capability, maintaining backward compatibility while enabling forward adaptability. This universal design resolves the contradiction between supporting more CORESETs and maintaining ease of manufacture/compatibility.
Solution Approach 2:
The patent introduces dynamic adaptability where the interpretation and usage of the MAC CE fields can change based on UE capability signaling. UEs can indicate their maximum supported CORESET count, and the network can dynamically adjust the indication strategy accordingly. This dynamic approach allows the system to optimize between legacy compatibility and enhanced functionality on a per-UE basis, resolving the contradiction between adaptability and ease of manufacture.
3Quantity of substance
If the CORESET ID field size is increased from 4 bits to 5 bits in the MAC CE, then the quantity of supported CORESETs is improved, but the loss of information in the existing MAC CE format increases
Solution Approach 1:
The patent segments the CORESET identification process into two separate indication fields: a first indication field for coarse grouping and a second indication field for fine identification. This segmentation distributes the information requirement across multiple fields, allowing the system to support more CORESETs (2^5 = 32) without requiring a single large field that would consume excessive MAC CE information capacity. Each individual field remains compact, resolving the contradiction between quantity supported and information loss.
Solution Approach 2:
The patent moves from a single-dimension indication field to a two-dimension indication structure. Instead of using one large field to identify all CORESETs directly, the system uses a hierarchical structure where the first dimension groups CORESETs and the second dimension identifies specific CORESETs within groups. This dimensional transformation efficiently utilizes the available information capacity in the MAC CE while supporting a larger total number of CORESETs.
Data Source
AI summary
Systems and methods for updating an active Transmission Configuration Indicator (TCI) state for multi-Physical Downlink Control Channel (PDCCH) based Multi-Transmission Reception Point (TRP) are provided. In some embodiments, a method performed by a wireless device for receiving one or more, TCI states includes: receiving a TCI state for at least one Control Resource Set (CORESET) using a control message comprising seven or more bits of TCI State ID field. In this way, the control message can be used to receive additional TCI states. In some embodiments, this allows the physical cell ID to be added to the TCI state.