5G TRS Configuration for Multi-TRP Beam Management
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Solution Overview
Problem
In 5G MIMO systems operating at high bands, existing beam management procedures for Reference Signals (RS) and Tracking Reference Signals (TRS) face challenges in efficiently determining optimal beam configurations and time/frequency offset tracking, especially in multi-TRP operations where different TRPs have varying numerologies and beams may have different offsets.
Innovation Solution
The proposed solution involves an apparatus with processing circuitry in an access node that determines the time and frequency densities of TRS based on bandwidth and subcarrier spacing, and encodes TRS with quasi co-location relationships for transmission, allowing for improved beam management and offset tracking by decoding RSs to identify better beam quality and adjust configurations accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a subset of SS block beams or CSI-RS beams is configured for beam measurement to reduce the number of beams to be measured, then the measurement complexity is reduced, but the ability to find new better beams outside the configured beams is limited
Solution Approach 1:
The patent segments the beam measurement process into two phases: initial beam measurement using a configured subset of beams, and subsequent beam refinement by searching for new better beams outside the configured subset. This segmentation allows the system to balance measurement complexity with beam selection flexibility by handling different measurement stages differently.
Solution Approach 2:
The patent introduces dynamic beam measurement capabilities where the UE can transition from measuring a configured subset of beams to actively searching for new better beams outside this subset. This dynamic approach allows the system to adapt beam measurement strategies based on current channel conditions and performance requirements, resolving the contradiction between fixed configuration and flexible adaptation.
2Measurement precision
If TRS instances are transmitted across multiple slots for Doppler spread estimation, then time and frequency offset tracking accuracy is improved, but the signaling overhead and configuration complexity increase
Solution Approach 1:
The patent changes key parameters of TRS configuration including the number of slots (N) over which TRS instances are transmitted, the subcarrier spacing, and the frequency density. By optimizing these parameters, the system achieves accurate Doppler spread estimation and time/frequency offset tracking while controlling configuration complexity through standardized parameter sets and efficient signaling mechanisms.
3Adaptability or versatility
If different TRPs use different numerologies and beam configurations, then the system supports diverse service requirements, but the UE cannot simultaneously receive signals from multiple TRPs for offset tracking
Solution Approach 1:
The patent applies preliminary action by having the network configure multiple TRS resources in advance, each associated with different TRPs and their respective numerologies. The UE is pre-configured with the necessary TRS resource information including time-frequency locations and QCL relationships, enabling it to perform offset tracking for multiple TRPs even when signals cannot be simultaneously received, thus ensuring reliable multi-TRP operation.
4Area of stationary object
If wide beams are used for SS blocks to cover larger areas, then coverage is improved, but beamforming gain is reduced compared to narrow beams
Solution Approach 1:
The patent segments the beam coverage into two levels: wide SS block beams for initial access and coverage, followed by narrower CSI-RS beams for refined beam management. This segmentation allows the system to first establish broad coverage with wide beams, then transition to narrower beams that provide higher beamforming gain for specific user equipment, effectively resolving the contradiction between coverage area and beamforming gain.
Data Source
AI summary
Provided herein are method and apparatus for configuration of a Reference Signal (RS) and a Tracking Reference Signal (TRS). An embodiment provides a method for a user equipment (UE), including determining a number of slots for a Tracking Reference Signal (TRS), wherein the number of slots is based on a subcarrier spacing of a bandwidth part (BWP) in a current component carrier for the UE; and receiving TRS based on the number of slots and a quasi co-location (QCL) relationship of the TRS, wherein the QCL relationship indicates that the TRS is Quasi-Co-Located (QCLed) with a Synchronization Signal (SS) block or a Channel State Information Reference Signal (CSI-RS).