Two-Step Random Access Contention Resolution via PDCCH Blind Detection
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Solution Overview
Problem
The two-step random access procedure in communication systems faces contention conflicts due to shared first messages among multiple terminal devices, which existing methods struggle to resolve efficiently.
Innovation Solution
The network device sends both first and second PDCCHs to the terminal device, allowing it to determine whether to blindly detect the second PDCCH based on the blind detection result of the first PDCCH, thereby resolving the contention conflict.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple terminal devices share the first message in two-step random access procedure, then resource utilization is improved, but contention conflict occurs
Solution Approach 1:
The patent segments the random access procedure into two distinct steps: Step 1 (MsgA transmission) and Step 2 (MsgB reception and contention resolution). By separating the shared resource transmission from the contention resolution phase, multiple devices can share MsgA resources without causing conflicts, as each device independently resolves contention in Step 2 based on its own MsgB reception status.
Solution Approach 2:
The patent performs preliminary contention resolution preparation in Step 1 by having devices transmit their identifiers in MsgA. The network device prepares resolution information in advance and includes it in MsgB, allowing devices to resolve contention before proceeding to data transmission, thus preventing conflicts from propagating to subsequent communication phases.
2Reliability
If terminal device blindly detects both first PDCCH and second PDCCH, then contention resolution reliability is improved, but energy consumption increases
Solution Approach 1:
The patent performs preliminary detection of the first PDCCH to obtain scheduling information for the second PDCCH. Based on the detection result of the first PDCCH, the terminal device determines whether to proceed with blind detection of the second PDCCH. This preliminary action allows the device to avoid unnecessary energy-consuming blind detections when the first PDCCH indicates no scheduled transmission, while still maintaining reliable contention resolution when needed.
Solution Approach 2:
The patent makes the blind detection process dynamic by adjusting the detection strategy based on the first PDCCH result. When the first PDCCH indicates scheduled transmission, the device performs blind detection of the second PDCCH; when it indicates no transmission, the device skips blind detection. This dynamic adaptation optimizes energy consumption while maintaining reliability based on actual system state.
Data Source
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AI summary
The embodiments of the present application relate to random access method and device, the method including: sending, by a terminal device, a first message to a network device, where the first message includes a random access preamble and UL message, and the UL message includes a first identifier; determining, by the terminal device, a first target radio network temporary identifier RNTI used for blindly detecting a first physical downlink control channel PDCCH according to the first identifier; blindly detecting, by the terminal device, the first PDCCH according to the first target RNTI; determining, by the terminal device, whether a contention conflict in a random access procedure is resolved according to a blind detection result of the first PDCCH or a first physical downlink shared channel PDSCH scheduled by the first PDCCH. The random access method and device of the embodiments of the present application can resolve a contention conflict in a two-step random access procedure.