MsgB Multiplexing for Two-Step RACH Reliability

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Solution Overview

Problem

Current wireless communication systems, particularly in LTE and NR technologies, face challenges in efficiently managing random access response (RAR) mappings for two-step random access channel procedures, leading to increased power consumption and processing demands on user equipment (UEs).

Innovation Solution

The proposed solution involves a base station (BS) multiplexing multiple random access responses (RARs) into a single message B (msgB) communication, allowing for reduced msgB communications transmitted to UEs. This approach includes grouping and selectively multiplexing RARs based on priorities, payload sizes, and RAR reception windows, as well as providing early indicators for UEs to identify the msgB communication carrying their RAR.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple RARs are transmitted separately to UEs, then each UE can receive its RAR reliably, but the number of msgB communications increases leading to higher power consumption and processing demands at UEs

Engineering Contradiction:
ImproveRAR reception reliabilityVSAvoidUE power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent combines multiple Random Access Responses (RARs) into a single msgB communication message. The base station multiplexes RARs for multiple UEs into one consolidated msgB message, which is then transmitted to the UEs. This merging approach reduces the total number of separate msgB communications, thereby lowering power consumption and processing requirements at the UE while maintaining reliable RAR delivery through proper multiplexing and identification mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple RARs are transmitted separately to UEs, then each UE can receive its RAR reliably, but the processing and memory demands at UEs increase

Engineering Contradiction:
ImproveRAR reception reliabilityVSAvoidUE processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent consolidates multiple RARs into a single msgB communication message with a structured format that includes a common payload and individual RAR entries. Each RAR is properly identified and organized within the unified message structure, allowing UEs to efficiently process only their relevant RAR information without handling multiple separate messages, thus reducing processing and memory demands while ensuring reliable reception.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If fewer msgB communications are transmitted, then power consumption and processing demands at UEs are reduced, but the complexity of multiplexing and identifying RARs increases

Engineering Contradiction:
ImproveUE power consumptionVSAvoidRAR multiplexing complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements a structured msgB communication format that consolidates multiple RARs with clear identification mechanisms. The message includes a common payload section and organized RAR entries, allowing the base station to efficiently multiplex multiple RARs into fewer messages while enabling UEs to easily identify and extract their specific RAR information through standardized formatting and identification fields.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the msgB communication message into distinct sections including a common payload and individual RAR entries. Each RAR is properly delimited and identified within the segmented structure, allowing for efficient multiplexing at the base station while enabling straightforward parsing and identification at the UE side, thus managing complexity through organized segmentation.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4042820B1Random access response mapping for two-step random access channel procedure
Publication Date: 2025.02.12 QUALCOMM INC
  • EP4042820B1 patent drawingFigure 1
  • EP4042820B1 patent drawingFigure 2
  • EP4042820B1 patent drawingFigure 3A

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station (BS) may group and selectively multiplex a plurality of random access channel responses (RARs) and radio resource control (RRC) messages in a message B (msgB) communication, together with supplementary scheduling information for other RARs to be mapped to a different msgB communication. The BS may transmit the msgB communication to one or more user equipments. Numerous other aspects are provided.