Uplink Spatial Relation Determination via Secondary Cell Resources
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Solution Overview
Problem
In 5G mobile communication systems, high-frequency communication faces challenges with signal energy decreasing rapidly with increasing transmission distance, leading to short transmission distances. Current solutions, such as analog beam technology and large-scale antenna arrays, require frequent reconfiguration of optimal uplink transmission beams, resulting in high signaling overheads.
Innovation Solution
The method involves a terminal device determining a spatial relation for uplink transmission by using a resource from a secondary cell, allowing it to perform uplink transmission without relying on RRC reconfiguration signaling from the network device. This approach reduces the need for frequent signaling and lowers signaling overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RRC reconfiguration signaling is used to reconfigure optimal uplink transmission beams when the terminal device moves, then the uplink transmission quality is maintained, but signaling overheads increase and transmission efficiency decreases
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple spatial relations for uplink transmission at different stages (e.g., during random access, handover, and normal operation). The terminal device and network device establish a set of spatial relations in advance, so when beam reconfiguration is needed, the terminal can switch to a pre-established spatial relation without requiring new RRC signaling, thus reducing signaling overhead while maintaining transmission quality.
Solution Approach 2:
The patent implements dynamics by enabling the terminal device to dynamically select from multiple pre-configured spatial relations based on current channel conditions and movement state. The spatial relation configuration includes multiple options with different priorities, allowing the terminal to adaptively choose the most appropriate spatial relation without frequent network reconfiguration, balancing reliability and signaling efficiency.
2Reliability
If RRC reconfiguration signaling is frequently sent to update optimal uplink transmission beams during quick terminal movement, then uplink transmission reliability is maintained, but transmission efficiency decreases
Solution Approach 1:
The patent pre-establishes multiple spatial relations during initial access and handover procedures, creating a pool of ready-to-use beam configurations. When the terminal moves quickly, it can switch between these pre-configured spatial relations using lightweight indications rather than full RRC reconfiguration, maintaining reliability while improving transmission efficiency by avoiding frequent signaling exchanges.
Solution Approach 2:
The patent segments the beam management process into distinct phases: initial spatial relation configuration during random access, supplementary configuration during handover, and dynamic selection during normal operation. This segmentation allows different levels of signaling overhead for different operational stages, improving overall transmission efficiency while maintaining reliability where most needed.
3Loss of information
If multiple spatial relations are pre-configured for uplink transmission at different stages, then signaling overheads are reduced, but device complexity increases
Solution Approach 1:
The patent uses dynamic selection mechanisms where the terminal device chooses from pre-configured spatial relations based on simple criteria such as priority indicators or current radio conditions. The selection process follows defined rules (e.g., selecting the first spatial relation with valid configuration, or the one with highest priority), keeping the device complexity manageable while achieving significant signaling overhead reduction.
Solution Approach 2:
The patent performs complex spatial relation configuration work in advance during random access and handover procedures, when the terminal is already establishing connections with the network. By completing the heavy configuration task preliminarily, the actual beam switching during normal operation requires only simple selections, reducing real-time device complexity while maintaining low signaling overheads.
4Loss of information
If the terminal device determines spatial relation using resources from another cell, then RRC reconfiguration signaling is reduced, but measurement precision requirements increase
Solution Approach 1:
The patent applies universality by using downlink reference signals (such as SSB or CSI-RS) that serve multiple functions: they are used for channel estimation, beam measurement, and spatial relation determination. The same reference signal resources configured for downlink transmission are reused for uplink spatial relation configuration, eliminating the need for separate measurement signals and reducing measurement precision requirements while still achieving accurate beam alignment.
Solution Approach 2:
The patent uses downlink reference signals as an intermediary to bridge the connection between downlink and uplink beam management. The terminal measures the downlink reference signal from the target cell, uses this measurement to determine the spatial relation for uplink transmission to another cell, and the network device validates this through the reference signal quality. This intermediary approach allows cross-cell spatial relation configuration without requiring direct uplink measurements, reducing measurement precision requirements.
Data Source
AI summary
Example uplink transmission methods and apparatus are described. One example method includes determining a spatial relation for uplink transmission of a first cell by a terminal device by using a first resource in a second cell. The terminal device performs uplink transmission in the first cell based on the spatial relation for uplink transmission of the first cell.