5G PDU Session ID Extension for Relay UE Capacity

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Solution Overview

Problem

Existing 5G communication systems are limited in supporting a maximum of 15 PDU sessions, particularly for Unstructured PDU sessions, restricting the number of remote UEs that can be served by a relay UE.

Innovation Solution

Extend the number of supported PDU sessions by introducing new capabilities and information elements in the UE and network to support more than 15 PDU sessions, including new bits and IEs for PDU session IDs, uplink data status, and PDU session status, allowing for increased flexibility in PDU session management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the number of PDU sessions is limited to 15 as per existing 5G systems, then the system complexity is maintained at a manageable level, but the ability to serve remote UEs through relay UE is restricted

Engineering Contradiction:
Improvenumber of supported PDU sessionsVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The PDU session ID field is segmented into two parts: a 4-bit PDU session ID (supporting up to 15 sessions) and an additional 4-bit extension field (supporting sessions 16-31). This segmentation allows the system to maintain backward compatibility with existing 4-bit ID structures while extending the total session capacity to 32 through the addition of the extension field.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a new dimension to the PDU session identification by introducing an extension field that works in conjunction with the existing PDU session ID. This dimensional extension transforms the identification space from a single 4-bit field to a combined structure that can represent up to 32 unique session identifiers, effectively doubling the session capacity without fundamentally changing the core identification mechanism.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If the PDU session ID field is extended to support more than 15 sessions, then more remote UEs can be served, but the protocol message size and processing complexity increase

Engineering Contradiction:
Improvenumber of PDU sessionsVSAvoidprotocol processing complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The session identification is segmented into the original PDU session ID (4 bits) and an extension field (4 bits). This segmentation allows protocols to selectively use only the necessary portion of the identification space, maintaining efficiency for sessions 1-15 while enabling extension to sessions 16-31 when needed, without requiring complete protocol redesign.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The extension field is introduced as an optional or conditional element that is only activated when sessions beyond 15 are required. For typical scenarios involving fewer sessions, the system operates with the original 4-bit ID, avoiding the overhead of processing the extended format. This partial action approach minimizes the impact on protocol complexity while providing the capability for extended session support when necessary.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4201151B1Improvements in and relating to managing PDU sessions in a telecommunication system
Publication Date: 2026.04.08 SAMSUNG ELECTRONICS CO LTD
  • EP4201151B1 patent drawingFigure 1
  • EP4201151B1 patent drawingFigure 2~5
  • EP4201151B1 patent drawingFigure 6~8

AI summary

The disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as a smart home, a smart building, a smart city, a smart car, a connected car, health care, digital education, smart retail, security and safety services. Methods and apparatuses for supporting a plurality of PDU sessions are provided.