2-Step RA Message A Resource Mapping for NTN Timing Advance
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Solution Overview
Problem
In non-terrestrial networks, the large variation in signal transmission delays between user equipments and a satellite results in overlapping preamble receiving windows, making it difficult for the base station to determine the timing advance of the user equipments during random access, especially in 2-step random access procedures.
Innovation Solution
A method for 2-step random access message A resource configuration that includes PRACH and PUSCH resource configurations, where the correspondence between PRACH and PUSCH time-domain resource locations is constrained to avoid overlapping receiving windows, ensuring that each preamble is associated with a unique RO time-domain resource location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the preamble receiving window length is extended to accommodate large signal transmission delay differences in NTN, then the base station can receive preambles from different UEs, but the receiving windows of adjacent ROs overlap in time, causing ambiguity in determining which RO a preamble belongs to
Solution Approach 1:
The patent segments the PUSCH resources into multiple sets, where each set corresponds to a specific RO. By dividing the PUSCH resources into distinct sets and associating each set with a specific RO, the system eliminates the ambiguity of overlapping receiving windows while maintaining the extended window length necessary for NTN coverage. This segmentation allows the base station to identify which RO a preamble belongs to even when receiving windows overlap in time.
Solution Approach 2:
The patent introduces a correspondence relationship between PRACH time-domain resource configuration and PUSCH resource configurations as an intermediary mechanism. This correspondence acts as a mediator that links the extended preamble receiving window with unique RO identification, allowing the base station to disambiguate overlapping receiving windows by referencing the configured correspondence between PRACH and PUSCH resources.
2Productivity
If the time interval between adjacent ROs is reduced to increase random access capacity, then more UEs can access the network simultaneously, but the preamble receiving windows overlap causing timing advance determination failure
Solution Approach 1:
The patent segments PUSCH resources into multiple sets corresponding to different ROs, enabling the system to support closer RO spacing while maintaining timing advance determination accuracy. By associating each PUSCH set with a specific RO, the system can reduce the time interval between ROs to increase capacity without causing ambiguity in TA determination.
Solution Approach 2:
The patent establishes a feedback mechanism where the base station uses the correspondence between PRACH and PUSCH resources to identify the correct RO after receiving a preamble. This feedback mechanism allows the system to maintain accurate TA determination even when ROs are closely spaced and receiving windows overlap, thereby enabling higher random access capacity.
3Loss of information
If multiple PUSCH resource configurations are used to correspond to different ROs, then the ambiguity in overlapping receiving windows is resolved, but the configuration complexity increases
Solution Approach 1:
The patent makes the PUSCH resource configurations serve multiple functions: they not only carry uplink data but also serve as identifiers to distinguish different ROs. By making the PUSCH configurations universal (serving both data transmission and RO identification), the system resolves ambiguity in overlapping receiving windows without requiring separate, dedicated identification mechanisms, thus limiting the increase in configuration complexity.
Data Source
AI summary
Methods for 2-step random access (RA) message (MSG) A resource configuration and a terminal device are provided. The method includes receiving first configuration information from a network device. The first configuration information includes a physical random access channel (PRACH) resource configuration of a 2-step RA MSG A resource, physical uplink shared channel (PUSCH) resource configurations of the 2-step RA MSG A resource, and a correspondence between a PRACH time-domain resource configuration and the PUSCH resource configurations. The PRACH resource configuration includes the PRACH time-domain resource configuration, and the PRACH time-domain resource configuration is for determining random access channel (RACH) occasion (RO) time-domain resource locations. The correspondence is for constraining PUSCH occasions (POs) corresponding to different RO time-domain resource locations to be distributed on different PUSCH resource configurations during any period of time having a length equal to a length of a preamble receiving window.