PRACH Uplink Control Across Multiple Candidate Cells
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Solution Overview
Problem
In future radio communication systems, controlling uplink (UL) transmission for multiple candidate cells is challenging, leading to potential degradation of communication quality due to inadequate timing advance management.
Innovation Solution
A terminal equipped with a receiving section to indicate candidate cell indices or timing advance group IDs on a physical downlink control channel, and a control section to manage PRACH transmissions accordingly, enabling appropriate UL control across multiple cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UL transmission is enabled for multiple candidate cells, then communication capacity and flexibility are improved, but timing advance control complexity increases and communication quality may degrade
Solution Approach 1:
The patent segments the timing advance control by introducing separate timing advance groups (TAGs) for different cell groups. Each TAG manages timing advance independently for its associated cells, allowing fine-grained control. The UE can be configured with multiple TAGs (e.g., first TAG for first cell group, second TAG for second cell group), enabling independent timing management for each cell or cell group without overwhelming complexity.
Solution Approach 2:
The patent implements dynamic timing advance adjustment through MAC control elements that can be transmitted periodically or aperiodically. The network can dynamically switch between different timing advance groups based on UE movement and communication conditions. This dynamic adaptation allows the system to optimize timing control in real-time without requiring complex static configurations.
2Productivity
If multiple candidate cells are used for communication, then communication capacity increases, but interference between cells may increase without proper timing control
Solution Approach 1:
By segmenting timing advance control into separate TAGs for different cell groups, the patent ensures that timing adjustments for one cell group do not interfere with another. This segmentation isolates timing control mechanisms, preventing timing-related interference between multiple candidate cells while maintaining high communication capacity.
Solution Approach 2:
The patent incorporates feedback mechanisms where the network monitors communication quality and timing conditions across multiple cells. Based on this feedback, the network can adjust timing advance parameters dynamically through MAC control elements, optimizing timing control to minimize interference while maximizing communication capacity.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A terminal according to one aspect of the present disclosure includes a receiving section that receives an indication of one or a plurality of candidate cell indices or timing advance group (TAG) IDs for physical random access channel (PRACH) transmission on a physical link downlink control channel (PDCCH), and a control section that controls the PRACH transmission to candidate cell(s) corresponding to the candidate cell index(ices) or the TAG ID(s), based on the indication. According to one aspect of the present disclosure, UL transmission can be appropriately controlled even when the UL transmission can be performed for a plurality of candidate cells.