Compact DCI Scheduling for Two-Step Random Access Coverage

Solution Overview

Problem

The bottleneck of downlink control information (DCI) in wireless communications systems limits the coverage of the second random access message during two-step and four-step random access procedures, particularly due to the large payload and cyclic redundancy check (CRC) bits, which reduces the scheduling efficiency and coverage of RRC connections.

Innovation Solution

Implementing a compact DCI with fewer information bits and CRC bits to schedule the second random access message, allowing for more reliable transmission in control resource sets and improving coverage in both two-step and four-step random access procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standard DCI with full payload and CRC bits is used to schedule the second random access message, then the control information contains complete scheduling details, but the coverage of the random access message is limited and scheduling efficiency is reduced

Engineering Contradiction:

Improvecoverage of second random access messageVSAvoidpayload size of DCI

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential scheduling information from the full DCI payload, creating a compact DCI format that contains only the minimum necessary bits to schedule the second random access message. This extraction approach reduces the DCI size while maintaining sufficient scheduling capability, thereby improving coverage without completely sacrificing scheduling detail.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter of DCI payload size from the standard full-size format to a reduced compact format. By modifying this key parameter, the system achieves better coverage performance while adapting the control information to be more suitable for random access procedures where coverage is the primary concern.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If a compact DCI with fewer information bits and CRC bits is used to schedule the second random access message, then the coverage and scheduling efficiency are improved, but the amount of control information transmitted is reduced

Engineering Contradiction:

Improvescheduling efficiency of second random access messageVSAvoidcontrol information bits in DCI

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent extracts only the essential scheduling information from the full DCI payload, creating a compact DCI format that contains only the minimum necessary bits to schedule the second random access message. This extraction approach reduces the DCI size while maintaining sufficient scheduling capability, thereby improving coverage without completely sacrificing scheduling detail.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter of DCI payload size from the standard full-size format to a reduced compact format. By modifying this key parameter, the system achieves better coverage performance while adapting the control information to be more suitable for random access procedures where coverage is the primary concern.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the DCI payload size is reduced for compact DCI, then the coverage is improved, but the scheduling flexibility may be limited

Engineering Contradiction:

Improvecoverage of downlink control informationVSAvoidscheduling flexibility of DCI

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent extracts only the essential scheduling information from the full DCI payload, creating a compact DCI format that contains only the minimum necessary bits to schedule the second random access message. This extraction approach reduces the DCI size while maintaining sufficient scheduling capability, thereby improving coverage without completely sacrificing scheduling detail.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent designs the compact DCI to be universally applicable for scheduling the second random access message in various scenarios. By creating a standardized compact format that can be used across different random access situations, the system achieves both improved coverage and maintained adaptability for the specific use case of random access procedure scheduling.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4115554B1Compact downlink control information for a two-step random access channel procedure

Publication Date: 2026.03.18 QUALCOMM INC

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AI summary

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit, to a base station, a first message of a two-step random access procedure. An attribute or content of the first message may indicate a request for a second type of control signaling that including fewer bits than a first type of control signaling. The UE may receive a second message of the two-step random access procedure including the second type of control signaling based on the first message. The UE may communicate with the base station on resources scheduled by the second message on a downlink shared channel.