2-Step Random Access RNTI Calculation for Response Identification
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Solution Overview
Problem
In communication technologies, particularly in LTE and NR systems, there is a challenge in distinguishing between random access responses (Msg2 and msgB) intended for different user equipment (UE) using 4-step and 2-step random access protocols, leading to potential misidentification and confusion.
Innovation Solution
The method involves calculating a first RNTI different from the RA-RNTI used in the 4-step random access, using this RNTI to detect downlink control information scheduling a random access response, and receiving the response in a physical downlink shared channel according to the detected information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the RA-RNTI is used to scramble CRC for DCI scheduling random access response in 2-step random access, then the existing 4-step random access mechanism can be reused, but user equipment may mistakenly identify random access responses intended for other ROs as its own response
Solution Approach 1:
The patent applies local quality by making the RNTI value dependent on the specific RO (Random Access Occasion) parameters. Each RO is assigned a unique RNTI calculated from its time-frequency position, ensuring that random access responses are locally tailored to specific ROs. This prevents UE from mistakenly identifying responses for other ROs while maintaining the overall structure of the existing mechanism.
Solution Approach 2:
The patent changes the parameter used for RNTI calculation from a fixed value to a dynamic value derived from RO parameters (s_id, t_id, f_id). By modifying the RNTI parameter to be RO-specific, the system maintains compatibility with existing 4-step random access procedures while enabling reliable distinction between responses for different ROs in 2-step random access.
2Device complexity
If a single RNTI is used for both 4-step and 2-step random access, then the system complexity is reduced, but confusion arises between RNTIs of different random access types
Solution Approach 1:
The patent applies universality by designing an RNTI calculation formula that serves both 4-step and 2-step random access types. The same RNTI structure and calculation method are used across both random access types, allowing a single unified mechanism to handle different access procedures without requiring separate RNTI management systems.
Solution Approach 2:
The patent segments the RNTI space by incorporating RO-specific parameters into the RNTI calculation. This segmentation ensures that RNTIs for different ROs and random access types are distinct, preventing confusion while maintaining a unified RNTI management approach. The segmentation is achieved through the formula that includes s_id, t_id, and f_id parameters.
Data Source
AI summary
A terminal apparatus includes: a transmitter configured to transmit a random access preamble and a physical uplink shard channel corresponding to the random access preamble; processor circuitry configured to: determine a first RNTI (Radio Network Temporary Identifier), control to start a monitoring window from a symbol after a slot or a symbol where the physical uplink shard channel is located; and control a position of the monitoring window to be not change even when the transmitter transmits the random access preamble without transmitting the physical uplink shard channel, and a receiver configured to: detect, within the monitoring window, downlink control information using the first RNTI, the downlink control information scheduling a random access response, and receive the random access response according to the downlink control information.