LIS-Assisted UE Initial Access for Wireless Shadow Areas

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Solution Overview

Problem

Conventional large intelligent surfaces (LIS) lack the ability to dynamically adjust their reflection patterns to support mobile terminals effectively, making it difficult for user equipment (UE) to access the base station (BS) in shadow areas.

Innovation Solution

A method for UE to perform initial access to a BS using LIS involves receiving a UE search signal, transmitting an initial access signal, and controlling the LIS reflection pattern through resource allocation information, including a first LIS control signal, with timing aligned within a cyclic prefix period, to facilitate beam direction determination and beamforming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional large intelligent surfaces are used, then the structure is simple and cost-effective, but the reflection pattern cannot be dynamically adjusted to support mobile terminals in shadow areas

Engineering Contradiction:

Improvedynamic adjustment capabilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the Dynamics principle by enabling the LIS to dynamically adjust its reflection pattern through beam control signals exchanged between the base station and user equipment. The LIS transitions from a static reflective surface to a dynamic one that can adapt beam directions and reflection patterns in real-time to support mobile terminals in shadow areas, resolving the contradiction between adaptability and complexity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements Feedback by establishing a control loop where the base station and UE exchange beam control signals to adjust the LIS reflection pattern. The system receives feedback about channel conditions and terminal positions, then adjusts the LIS configuration accordingly, enabling dynamic adaptation while maintaining manageable system complexity through structured feedback mechanisms.

Inventive Principle:

Principle #23Feedback

2Reliability

If the LIS reflection pattern is dynamically controlled, then mobile terminal access in shadow areas is enabled, but the control signaling overhead increases

Engineering Contradiction:

Improveaccess reliabilityVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent appliesUniversality by designing the beam control signal framework to serve multiple purposes: it controls LIS reflection patterns, enables initial access, maintains connectivity, and supports mobility management. This multi-functionality reduces the need for separate dedicated control signals, thereby reducing overall signaling overhead while maintaining access reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the LIS control functionality with existing base station and UE operations. The beam control signals are integrated into the existing uplink and downlink communication frameworks, combining multiple functions (data transmission, control signaling, and LIS adjustment) into unified signal exchanges, thereby reducing redundant signaling overhead.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If beam control signals are exchanged between base station and UE, then initial access in shadow areas is facilitated, but the timing synchronization requirements increase

Engineering Contradiction:

Improveinitial access capabilityVSAvoidtiming synchronization precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent introduces the LIS as an intermediary element that facilitates beam control between the base station and UE. The LIS acts as a passive reflective surface that can be controlled to redirect beams, mediating the interaction between BS and UE and reducing the direct timing synchronization burden on the mobile terminal while enabling initial access in shadow areas.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method effectively controls the reflection pattern of a large intelligent surface (LIS) within the existing resource region, enabling smooth legacy initial access to the BS in shadow areas by UE.

Implementation Method 1

a large intelligent surface (LIS) may serve as a reflective plate formed of a meta-material

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

the beamforming effect of the array antenna can be obtained through control of the reflection pattern of the LIS

Methodology Applied

Scientific EffectBeamforming:

Data Source

PatentUS12520165B2Method by which UE performs initial access to base station in wireless communication system, and device therefor

Publication Date: 2026.01.06 LG ELECTRONICS INC

AI summary

Various embodiments disclose a method by which a user equipment (UE) performs initial access to a base station by using a large intelligent surface (LIS) in a wireless communication system, and a device therefor. The method comprises the steps of: receiving, through the LIS, a UE search signal transmitted by the base station; transmitting an initial access signal to the base station through the LIS on the basis of resource allocation information included in the UE search signal; transmitting a first LIS control signal for controlling a reflection pattern of the LIS for an uplink signal; and receiving, through the LIS, an initial access response signal transmitted by the base station.