5G Preamble Allocation for RRC Flex State Access

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Solution Overview

Problem

In 5G networks, devices in the RRC_Flex state face challenges in obtaining a unique preamble sequence for contention-based access without undergoing a full handover process, leading to unnecessary signaling exchanges and power consumption, especially when moving between cells.

Innovation Solution

A modified random access procedure is introduced where user equipment (UE) can request a contention-based access preamble without entering the RRC_Connected state, allowing for UE-specific preamble allocation within a cell, and a timer-based approach for preamble release to avoid collisions and optimize resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If devices in RRC_Flex state undergo full handover process to obtain preamble sequence, then unique preamble allocation is achieved, but signaling overhead and power consumption increase

Engineering Contradiction:

Improvepreamble allocation reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the preamble request function from the full handover process, allowing devices in RRC_Flex state to obtain preambles through a simplified random access procedure without completing the entire handover sequence. This separation enables preamble acquisition independently of full network re-registration, reducing signaling overhead and energy consumption while maintaining reliable unique preamble allocation.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If full handover process is used for preamble acquisition, then network registration is updated, but latency increases

Engineering Contradiction:

Improvenetwork registration accuracyVSAvoidpreamble acquisition latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary preamble allocation where devices receive preambles before completing full handover procedures. The network node allocates preambles to devices in RRC_Flex state through enhanced random access, enabling devices to perform contention-based access immediately without waiting for complete handover registration, thus reducing latency while maintaining network awareness through subsequent uplink transmissions.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If simplified random access is used for preamble request, then signaling overhead is reduced, but resource collision risk increases

Engineering Contradiction:

Improveaccess efficiencyVSAvoidpreamble uniqueness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where the network node monitors random access attempts and provides responses to devices requesting preambles. The network tracks allocated preambles and manages collisions by providing feedback to devices about successful allocations or conflicts, enabling the simplified random access procedure to maintain preamble uniqueness while reducing signaling overhead compared to full handover processes.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11291044B2Apparatuses and methods for preamble sequence management for contention based access

Publication Date: 2022.03.29 NOKIA TECHNOLOGIES OY

AI summary

Systems, methods, apparatuses, and computer program products of preamble sequence management for contention based access are provided. One method may include a user equipment sending a contention based access (CBA) request message, such as a random access procedure (RACH) message, to a network node (e.g., a base station or eNB). The CBA request message may include an indication that the user equipment wants to obtain a preamble for CBA data transmission and is not for full network access. The method may then include receiving an allocation of a preamble for CBA from the network node.