Inter-Cell Timing Advance Signaling for Non-Serving PCI Uplink
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Solution Overview
Problem
In wireless communications systems, determining a timing advance (TA) for uplink transmissions associated with a physical cell identifier (PCI) different from the serving cell is unclear, as PRACH transmissions are not typically supported in non-serving cells, hindering efficient synchronization and system performance.
Innovation Solution
A method for a user equipment (UE) to receive a PDCCH order to trigger a PRACH transmission for an additional PCI, followed by transmitting a PRACH and receiving a TA indication via MAC-CE for the additional PCI, enabling synchronization with non-serving cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PRACH transmission is not supported in non-serving cells, then the system maintains simpler random access procedures, but the UE cannot obtain timing advance for uplink transmissions to non-serving cells
Solution Approach 1:
The patent enables PRACH transmission functionality in non-serving cells by configuring uplink resources and parameters through RRC signaling and DCI formats. The UE can now perform random access procedures not only in serving cells but also in non-serving cells, allowing timing advance acquisition for inter-cell uplink transmissions. This multi-functionality resolves the contradiction by expanding PRACH support beyond traditional serving cell limitations.
Solution Approach 2:
The patent introduces intermediate signaling mechanisms including RRC configuration messages, MAC control elements, and DCI formats that act as intermediaries to coordinate PRACH transmissions in non-serving cells. These intermediaries facilitate the complex interaction between UE and network by carrying timing advance commands, uplink resource allocations, and random access responses, enabling reliable TA acquisition without oversimplifying the procedure.
2Speed
If the UE synchronizes with non-serving cells using traditional methods, then the synchronization process is slower, but the system maintains simpler procedures
Solution Approach 1:
The patent implements preliminary configuration of uplink resources, power parameters, and random access patterns through RRC signaling before the UE actually performs PRACH transmission in non-serving cells. This preliminary setup enables faster synchronization by having all necessary parameters pre-configured, eliminating the need for iterative parameter negotiation during the synchronization process itself.
Solution Approach 2:
The patent dynamically adjusts transmission parameters including uplink power, timing advance values, and resource allocations based on the specific non-serving cell conditions. By changing these parameters adaptively through DCI formats and MAC control elements, the system achieves faster synchronization while managing complexity through standardized parameter adjustment mechanisms rather than procedural complexity.
Data Source
AI summary
Certain aspects of the present disclosure provide a method for wireless communication by a user equipment (UE) generally including receiving a physical downlink control channel (PDCCH) order to trigger a PRACH transmission associated with an additional PCI different from a first PCI associated with a serving cell, transmitting a PRACH associated with the additional PCI, receiving an indication, via a MAC-CE, of a timing advance (TA) associated with the additional PCI, and applying the TA for an uplink transmission associated with the additional PCI.