Cell-Specific Random Access Parameters for Interference Management

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Solution Overview

Problem

Existing wireless communication systems face challenges in managing inter-cell interference during two-step random access procedures, which affects the reliability of random access messaging and increases latency.

Innovation Solution

Implementing cell-specific transmission parameters or schemes, such as cell-specific preamble occasions, physical uplink shared channel occasions, hopping sequences, scrambling sequences, search spaces, and pathloss compensation factors, to differentiate random access messages and responses from those of other UEs in neighboring cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If contention-based random access is used, then access speed is improved, but inter-cell interference increases

Engineering Contradiction:
Improveaccess speedVSAvoidinter-cell interference
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent segments the random access resources by introducing cell-specific parameters including preamble occasions, physical uplink shared channel occasions, hopping sequences, scrambling sequences, search spaces, and pathloss compensation factors. Each cell is assigned unique combinations of these parameters, effectively dividing the shared random access resources into cell-specific segments. This segmentation allows UEs in different cells to perform random access simultaneously without causing inter-cell interference, while still maintaining the fast access speed of contention-based random access.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If cell-specific transmission parameters are implemented, then inter-cell interference is reduced, but system complexity increases

Engineering Contradiction:
Improveinter-cell interferenceVSAvoidsystem complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs a universal set of cell-specific parameters that serve multiple functions simultaneously. The same parameters (preamble occasions, physical uplink shared channel occasions, hopping sequences, scrambling sequences, search spaces, and pathloss compensation factors) are used across all cells to differentiate random access transmissions. This multi-functional approach allows the system to reduce inter-cell interference without requiring entirely new mechanisms for each cell, thereby limiting the increase in system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3935910B1Interference management for two-step random access
Publication Date: 2025.04.16 QUALCOMM INC
  • EP3935910B1 patent drawingFigure 1
  • EP3935910B1 patent drawingFigure 2
  • EP3935910B1 patent drawingFigure 3A~3C

AI summary

Methods, systems, and devices for wireless communications are described. A base station may receive, from a user equipment (UE), a first random access message of a two-step random access procedure. In some examples, the first random access message may be transmitted by the UE based on one or more cell-specific transmission parameters or cell-specific transmission schemes. The base station may transmit, to the UE, a second random access response message of the two-step random access procedure in response to the first random access message. The second random access response message being transmitted based on one or more cell-specific transmission parameters or cell-specific transmission schemes. Accordingly, the base station and the UE may establish a connection with the UE based on the first random access message and the second random access response message, or the base station can indicate to the UE to return to an inactive mode or idle state.