Random Access Response Signaling Without PDSCH Scheduling Delay

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Solution Overview

Problem

The use of physical downlink control channel (PDCCH) to schedule physical downlink shared channel (PDSCH) for transmitting MSG2 in random access procedures significantly increases access delay.

Innovation Solution

Direct transmission of MSG2 through physical downlink control channel (PDCCH) without scheduling PDSCH, utilizing DCI that includes scheduling information such as a timing advance command, uplink grant, and temporary cell-radio network temporary identifier (Temporary C-RNTI) to scramble and send MSG3 at a specified time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If PDCCH is used to schedule PDSCH for transmitting MSG2, then the random access response can be transmitted, but the access delay significantly increases

Engineering Contradiction:

Improveaccess delayVSAvoidscheduling procedure complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent extracts the MSG2 transmission function from the PDSCH channel and places it directly in the PDCCH channel. By removing the scheduling step and transmitting MSG2 directly through PDCCH, the patent eliminates the time delay caused by PDCCH-PDSCH scheduling while maintaining the necessary control and response functions.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the MSG2 transmission function with the PDCCH channel by allowing PDCCH to carry both control information and the random access response. This consolidation eliminates the separate PDSCH scheduling step and reduces the overall access delay by combining multiple functions into a single transmission path.

Inventive Principle:

Principle #5Merging (Combining)

2Productivity

If PDCCH schedules PDSCH for MSG2 transmission, then the response can be delivered, but the access time is extended

Engineering Contradiction:

Improverandom access speedVSAvoidaccess time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent skips the intermediate PDSCH scheduling step by directly transmitting MSG2 through PDCCH. This rushing through of the scheduling process eliminates the time delay and accelerates the random access response delivery, improving access speed without compromising the completeness of the response.

Inventive Principle:

Principle #21Skipping (Rushing through)

Solution Approach 2:

The patent performs preliminary action by incorporating the MSG2 transmission capability directly into the PDCCH structure, allowing the random access response to be prepared and transmitted in advance without waiting for separate PDSCH scheduling. This preliminary integration of transmission functions reduces access time and improves productivity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4507437B1Random access method and apparatus, storage medium, and electronic apparatus

Publication Date: 2026.04.22 ZTE CORP

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AI summary

The present disclosure provides a random access method, a random access apparatus, a storage medium, and an electronic device. The random access method is implemented through the cooperation of terminal device and network device. The random access method applied to a terminal device includes: sending a random access request to a network device; obtaining downlink control information corresponding to the terminal device sent by the network device from a physical downlink control channel according to the random access request, where the downlink control information includes a random access response; decoding the downlink control information, extracting scheduling information of a random access instruction from the random access response; and sending the random access instruction to the network device according to the scheduling information.