Random Access Procedure Selection via Physical Channel Indication

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Solution Overview

Problem

Current cellular communication systems, such as LTE and NR, face inefficiencies in random access procedures, particularly in contention-based and non-contention based access methods, which affect the overall performance and latency of initial access and handover processes.

Innovation Solution

A terminal apparatus and communication method that include a higher layer processing unit capable of initiating 2-step, 4-step contention-based, and non-contention based random access procedures based on physical channel indications, allowing for efficient random access by selecting the appropriate procedure based on received physical channel signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a 4-step contention-based random access procedure is used, then reliability of random access is improved, but latency and overhead increase

Engineering Contradiction:

Improverandom access reliabilityVSAvoidrandom access latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The random access procedure is segmented into two distinct types: contention-based (4-step) for high reliability scenarios, and contention-free (2-step) for low latency scenarios. The system segments the random access resource configuration to allow selective activation of different procedure types based on service requirements, thereby resolving the contradiction between reliability and latency by providing appropriate access methods for different conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The network dynamically configures and activates different random access procedure types (2-step or 4-step) based on terminal behavior patterns, service types, and network conditions. This dynamic adaptation allows the system to switch between contention-based and contention-free procedures, optimizing the balance between reliability and latency for different operational scenarios.

Inventive Principle:

Principle #15Dynamics

2Loss of time

If a 2-step contention-based random access procedure is used, then latency is reduced, but reliability and collision handling capability deteriorate

Engineering Contradiction:

Improverandom access latencyVSAvoidrandom access reliability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes key parameters of the random access procedure including the number of steps (2-step vs 4-step), contention resolution mechanisms, and resource allocation patterns. By adjusting these parameters based on service requirements and network conditions, the system optimizes the trade-off between latency reduction and reliability maintenance for different operational scenarios.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If non-contention based random access is used, then latency and overhead are reduced, but adaptability to different access scenarios decreases

Engineering Contradiction:

Improverandom access latencyVSAvoidrandom access adaptability

Core Design Contradiction:

Loss of timeVSAdaptability or versatility

Solution Approach 1:

The system implements a universal random access framework that supports multiple procedure types (2-step contention-free, 4-step contention-based, and non-contention-based) within a single configuration structure. This multi-functional approach allows the network to activate different random access procedures based on specific service requirements, terminal capabilities, and network conditions, thereby maintaining both low latency performance and high adaptability across diverse access scenarios.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If multiple random access procedure types are supported, then adaptability and efficiency are improved, but device complexity increases

Engineering Contradiction:

Improverandom access adaptabilityVSAvoidrandom access procedure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The network performs preliminary configuration of multiple random access procedure types in advance, defining resource allocations, procedure parameters, and activation conditions before actual random access operations. This pre-configuration approach allows terminals to efficiently select and execute appropriate procedures without complex real-time decision-making, reducing device complexity while maintaining high adaptability through pre-planned procedure variants.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11375546B2Terminal device, base station device, and communication method for performing random access procedure

Publication Date: 2022.06.28 SHARP KK

AI summary

A terminal apparatus performs a random access procedure; and receives a physical channel, in which the random access procedure includes a 2 step contention based random access procedure, a 4 step contention based random access procedure, and a non-contention based random access procedure, and the physical channel indicates an initiation of any of the 4 step contention based random access procedure and the non-contention based random access procedure.