Two-Step Random Access With Dedicated PUSCH Resources
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Solution Overview
Problem
Existing two-step random access procedures in wireless communication networks face challenges with contention-based PUSCH transmissions, as they can still result in collisions despite using contention-free preambles, necessitating support for dedicated PUSCH transmission resources to ensure efficient handover and cell group changes.
Innovation Solution
A two-step, contention-free random access procedure is implemented by providing a dedicated preamble and dedicated PUSCH transmission resources, configured through partial resource allocations indicated by dynamic signaling, ensuring collision-free PUSCH transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If contention-based random access is used with contention-free preambles, then handover efficiency is improved, but PUSCH collision risk increases
Solution Approach 1:
The patent segments the random access procedure into two distinct steps: Step 1 transmits only the preamble on PRACH, while Step 2 transmits the PUSCH message separately. This segmentation allows the system to use contention-free preambles for fast handover initiation while resolving PUSCH collision risks through separate resource allocation in Step 2, thereby maintaining handover efficiency while improving reliability.
2Reliability
If dedicated PUSCH resources are allocated for each UE, then PUSCH collision is eliminated, but resource allocation complexity increases
Solution Approach 1:
The patent applies preliminary action by allocating dedicated PUSCH resources to each UE in advance through dedicated RRC signaling before the random access procedure begins. This pre-allocation ensures that when the UE transmits PUSCH in Step 2, it uses pre-assigned collision-free resources, eliminating PUSCH collisions while avoiding the need for complex dynamic resource allocation during the random access procedure itself.
Data Source
AI summary
A UE is provided with a dedicated preamble for use in a two-step random access procedure, as well as dedicated, contention-free PUSCH transmission resources for the PUSCH part of msgA. In one embodiment, the base station transmits a partial PUSCH msgA configuration to the UE using dedicated RRC signaling. In another embodiment, the base station transmits a resource index to the UE indicative of a dedicated PUSCH resource for a msgA transmission via dedicated RRC signaling.