Random Access and Uplink Mobility Message Merging for Lower Latency

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Solution Overview

Problem

Existing wireless communication systems face latency issues in initial network access and mobility procedures due to the separation of messages in random access and mobility processes, leading to inefficient power consumption and increased latency.

Innovation Solution

A UE simultaneously transmits a random access preamble and data in a single transmission, and a base station responds with a combined random access and connection response, reducing the number of steps required for network access and mobility management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the random access procedure uses separate message transmissions (msg1, msg3) for preamble and data, then the protocol structure remains simple and manageable, but the random access latency increases and power consumption rises

Engineering Contradiction:
Improverandom access latencyVSAvoidmessage transmission steps
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent combines the random access preamble (msg1) and uplink data (msg3) into a single composite message transmission. The UE simultaneously transmits both the preamble sequence and uplink payload data in one uplink transmission, eliminating the need for separate msg1 and msg3 transmissions. This merging directly reduces random access latency while the base station processes both components together in the received signal.

Inventive Principle:
Principle #5Merging (Combining)

2Loss of time

If the base station sends separate random access response and connection response messages (msg2, msg4), then the response information is complete and accurate, but the overall access procedure latency increases

Engineering Contradiction:
Improveresponse procedure latencyVSAvoidresponse information completeness
Core Design Contradiction:
Loss of timeVSLoss of information

Solution Approach 1:

The patent merges the random access response (msg2) and connection response (msg4) into a single composite downlink message. The base station transmits both the random access response information and the connection setup information together in one downlink transmission, reducing the response procedure latency while maintaining complete information delivery to the UE.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If traditional DL-based mobility is used where the network sends reference signals and UE performs measurements, then the mobility management is comprehensive, but power consumption at the UE increases

Engineering Contradiction:
ImproveUE power consumptionVSAvoidmobility management efficiency
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent inverts the traditional downlink-based mobility measurement approach by implementing uplink-based mobility. Instead of the UE measuring downlink reference signals from multiple base stations, the base stations now measure uplink reference signals transmitted by the UE. This inversion significantly reduces UE power consumption since the UE only needs to transmit signals rather than continuously measure and process signals from multiple sources, while base stations with more processing power perform the measurement tasks.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3520539B1Improved random access procedure and uplink-based mobility
Publication Date: 2025.07.09 QUALCOMM INC
  • EP3520539B1 patent drawingFigure 1
  • EP3520539B1 patent drawingFigure 2
  • EP3520539B1 patent drawingFigure 3

AI summary

Wireless communications systems and methods related to random access and uplink (UL)-based mobility are provided. A first wireless communication device transmits a first signal carrying a random access sequence and a data. The first wireless communication device receives a second signal from a second wireless communication device in response to the first signal. For random access, the data in the first signal includes at least one of an identifier of the first wireless communication device or a connection request, and the second signal includes at least one of timing advance information or a contention resolution. For UL-based mobility, the data in the first signal includes at least an identifier of the first wireless communication device, and the second signal includes at least an acknowledgement for the first signal or paging information associated with the first wireless communication device.