SRS Resource Indicator Mapping for Multi-TRP Uplink Precoding
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing uplink transmissions between user equipment (UE) and multiple transmission and reception points (TRPs) due to limitations in interpreting control messages for sounding reference signal (SRS) resource indicators, particularly in multi-TRP operation modes.
Innovation Solution
A signaling-based mechanism that allows UE to dynamically switch between single and multi-TRP operation modes by interpreting DCI fields for SRS resource sets, SRI fields, and TPMI fields to optimize uplink shared channel transmissions based on the UE's capability to support multiple layers and ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE interprets DCI fields based on a maximum quantity of layers for mTRP operation mode, then the UE can support dynamic switching between sTRP and mTRP modes, but the complexity of interpreting DCI fields (SRI and TPMI) increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the interpretation of DCI fields based on the maximum quantity of layers configured for mTRP operation. When the maximum quantity of layers is 2, the SRI field is interpreted as indicating a single SRS resource set, and the TPMI field is interpreted accordingly. This parameter-based adaptation allows the UE to switch between sTRP and mTRP modes while maintaining manageable DCI field interpretation complexity through standardized mapping rules.
Solution Approach 2:
The patent implements universality by designing the DCI field interpretation mechanism to serve multiple functions: it supports both sTRP and mTRP operation modes, handles different quantities of SRS resource sets, and adapts to various maximum rank values. The same SRI and TPMI fields are universally interpreted based on the configured maximum quantity of layers, eliminating the need for separate field definitions for different operation modes.
2Adaptability or versatility
If the UE supports multiple SRS resource sets for CB usage, then the flexibility of uplink transmissions is improved, but the quantity of SRI fields and TPMI fields required increases
Solution Approach 1:
The patent applies merging by combining the functionality of multiple SRS resource sets into a unified DCI field interpretation framework. Instead of using separate SRI and TPMI fields for each SRS resource set, the patent merges them into a single interpretation mechanism where the SRI field indicates an SRS resource set from a configured set, and the TPMI field provides precoding information. This reduces the total quantity of fields while maintaining support for multiple SRS resource sets.
3Productivity
If the maximum rank value is increased to support more layers in mTRP mode, then the uplink transmission capability is improved, but the mapping between TPMI fields and SRS ports becomes more complex
Solution Approach 1:
The patent applies dynamics by making the mapping between TPMI fields and SRS ports adaptive to the configured maximum rank value. When the maximum rank value is increased to support more layers in mTRP mode, the mapping dynamically adjusts to accommodate the additional layers. The TPMI field content is mapped to a quantity of ports based on the maximum rank value, allowing the system to flexibly support different transmission capabilities without requiring a completely different mapping structure.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A UE may receive one or more control messages that indicate a quantity of a set of sounding reference signal (SRS) resource sets configured for codebook usage and at least one maximum rank value associated with uplink shared channel transmissions by the UE. The UE may receive downlink control information (DCI) with an SRS resource indicator (SRI) field and a transmit precoding matrix indicator (TPMI) field. The UE may then interpret the SRI and TPMI fields according to a mapping that is based on the maximum rank value and a maximum quantity of ports the UE is capable of supporting. Then, the UE may transmit the uplink shared channel message in accordance with the mapping.