Random Access BWP Switching for Wireless Communication Systems

Solution Overview

Problem

In wireless communication systems, particularly in 5G networks, there is a challenge in performing random access efficiently across different bandwidth parts (BWP) within a serving cell, especially when the active downlink (DL) BWP ID does not correspond to the active uplink (UL) BWP ID, leading to ambiguity in receiving random access responses.

Innovation Solution

A method is introduced where a terminal or base station identifies a random access occasion for an active UL BWP and switches the active DL BWP to match the ID of the active UL BWP based on BWP configuration information, ensuring correct BWP linkage and enabling successful random access by transmitting a radio resource control (RRC) message and using a physical downlink control channel (PDCCH) with a random access preamble index.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple bandwidth parts (BWPs) are configured for a serving cell, then the system supports frequency merging techniques and improves resource utilization, but ambiguity arises when the active DL BWP ID does not correspond to the active UL BWP ID, leading to failed random access responses

Engineering Contradiction:

Improvesupport for frequency merging techniquesVSAvoidrandom access response reception

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by making the BWP configuration cell-specific and direction-specific. Each cell can independently configure whether DL and UL BWPs are linked or independent, allowing the system to adapt locally to frequency merging requirements while maintaining reliable random access through explicit linkage configuration in the cell-specific parameter set

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by pre-configuring the linkage relationship between DL and UL BWPs through higher-layer signaling before random access occurs. The network configures the active DL BWP ID to match the active UL BWP ID in advance, eliminating ambiguity and ensuring reliable random access response reception

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the active DL BWP ID is kept independent from the active UL BWP ID, then frequency merging flexibility is improved, but the terminal cannot correctly identify which DL BWP to monitor for random access responses

Engineering Contradiction:

Improvefrequency merging flexibilityVSAvoidDL BWP identification for RAR

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent applies local quality by making the BWP configuration cell-specific and direction-specific. Each cell can independently configure whether DL and UL BWPs are linked or independent, allowing the system to adapt locally to frequency merging requirements while maintaining reliable random access through explicit linkage configuration in the cell-specific parameter set

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces an intermediary mechanism through higher-layer signaling that explicitly indicates the linkage relationship between DL and UL BWPs. This intermediary configuration allows the terminal to correctly identify the active DL BWP for monitoring random access responses, even when frequency merging is employed

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If BWP switching is performed to match DL and UL BWP IDs, then random access reliability is improved, but additional signaling overhead and processing time are required

Engineering Contradiction:

Improverandom access success rateVSAvoidBWP switching time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary action by pre-configuring the linkage relationship between DL and UL BWPs through higher-layer signaling before random access occurs. The network configures the active DL BWP ID to match the active UL BWP ID in advance, eliminating ambiguity and ensuring reliable random access response reception without requiring time-consuming switching operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies self-service by enabling the terminal to autonomously determine the active DL BWP for random access response monitoring based on pre-configured linkage information. The terminal uses the configured relationship between DL and UL BWP IDs to automatically identify the correct DL BWP without requiring additional network signaling or manual intervention during the random access procedure

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12177906B2Method and apparatus for performing random access in wireless communication system

Publication Date: 2024.12.24 SAMSUNG ELECTRONICS CO LTD

AI summary

A method, by a terminal, of performing a random access in a wireless communication system is provided. The method includes identifying a random access occasion configured for an active uplink (UL) bandwidth part (BWP) of a serving cell and when the serving cell is a special cell (SpCell) and an identity (ID) of an active downlink (DL) BWP does not correspond to an ID of the active UL BWP, switching the active DL BWP to a DL BWP with ID corresponding to the ID of the active UL BWP, based on BWP configuration information for the serving cell, and performing a random access on the switched DL BWP.