Random Access Response Filtering for Shared PDSCH Demodulation
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Solution Overview
Problem
In LTE and NR mobile communications systems, terminal devices demodulate unrelated physical downlink shared channels (PDSCH) due to shared random access time-frequency resources, leading to inefficiency and increased power consumption during random access procedures.
Innovation Solution
The method involves the use of indication information in DCI to determine the type of response information, scrambling codes, and search spaces to ensure that terminal devices only demodulate relevant PDSCHs, reducing unnecessary demodulation attempts and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If terminal devices use shared random access time-frequency resources for both four-step and two-step random access procedures, then resource utilization is improved, but terminal devices cannot determine whether received DCI belongs to them, leading to unnecessary PDSCH demodulation and increased power consumption
Solution Approach 1:
The patent applies preliminary action by introducing indication information in DCI that预先 indicates the type of response information before the terminal device attempts to demodulate PDSCH. This allows terminal devices to determine in advance whether the DCI and corresponding PDSCH are relevant to them, avoiding unnecessary demodulation operations and reducing power consumption while maintaining shared resource utilization
2Reliability
If terminal devices demodulate all PDSCH indicated by DCI scrambled with RA-RNTI, then response information can be received, but terminal devices waste time and energy demodulating unrelated PDSCH, reducing random access efficiency
Solution Approach 1:
The patent introduces indication information in DCI that预先 indicates the type of response information (four-step random access response or two-step random access response) before terminal devices demodulate PDSCH. Terminal devices compare this indication with their own random access type to determine whether to proceed with demodulation, ensuring reliable reception of relevant response information while avoiding waste of time and energy on unrelated PDSCH, thus improving random access efficiency
3Reliability
If terminal devices demodulate PDSCH without verifying response information type, then all possible responses can be received, but unnecessary demodulation increases processing overhead and reduces access efficiency
Solution Approach 1:
The patent applies preliminary action by including indication information in DCI that specifies the type of response information carried in PDSCH before terminal devices attempt demodulation. Terminal devices use this indication to verify whether the response information type matches their random access type, allowing them to skip demodulation of unrelated PDSCH. This reduces processing overhead while maintaining reliability by ensuring that relevant response information is not missed
Solution Approach 2:
The patent extracts the key identifying information (response information type indication) from the DCI and uses it as a filter before PDSCH demodulation. By taking out this critical information and checking it in advance, terminal devices can selectively process only relevant PDSCH, reducing unnecessary processing overhead while maintaining complete reception of relevant response information
Data Source
AI summary
This application provides a random access method. In the method, a terminal device receives first DCI from a network device. The first DCI includes the first indication information, where the first indication information is used to indicate the type of the response information carried on a PDSCH. The PDSCH carries response information for a random access request initiated by the terminal device. If determining that the type of the response information as indicated by the first indication information matches the random access type of the random access request initiated by the terminal device, the terminal device demodulates the PDSCH indicated by the first DCI. In this way, the terminal device demodulates the PDSCH indicated by the first DCI only when determining, based on the first indication information, that the PDSCH indicated by the received first DCI may belong to the terminal device.