Random Access Preamble Identifier for Telecommunication Latency

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Solution Overview

Problem

In LTE telecommunications systems, the random access procedure fails when all dedicated random access preambles are in use, leading to increased data latency due to the need for contention-free access, which is delayed until a dedicated preamble becomes available.

Innovation Solution

A method where the radio base station determines a Random Access Preamble Identifier (RAPID) and transmits it to the user equipment (UE), allowing the UE to select a non-dedicated random access preamble for contention-based access when dedicated preambles are unavailable, thereby enabling successful contention-based random access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated random access preambles are allocated for contention-free access, then access reliability is improved, but resource utilization deteriorates when all dedicated preambles are in use

Engineering Contradiction:

Improveaccess reliabilityVSAvoidresource utilization

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent makes the dedicated random access preamble serve multiple functions: it acts as both a dedicated preamble for contention-free access and as a signal to trigger contention-based access when all dedicated preambles are in use. The UE interprets the received dedicated preamble differently based on system conditions, enabling the same resource to fulfill multiple access modes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If contention-free random access is used, then access reliability is improved, but data latency increases when dedicated preambles are unavailable

Engineering Contradiction:

Improveaccess reliabilityVSAvoiddata latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Instead of waiting for dedicated preambles to become available before allowing access, the patent inverts the approach by using the dedicated preamble reception as a trigger to switch to contention-based access. This allows the system to proceed with access immediately rather than waiting, thereby reducing latency while maintaining reliability through the alternative access mode.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If non-dedicated random access preambles are used for contention-based access, then resource efficiency is improved, but access reliability deteriorates due to potential collisions

Engineering Contradiction:

Improveresource efficiencyVSAvoidaccess reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The dedicated random access preamble acts as an intermediary mechanism that coordinates between the network and UE before allowing contention-based access. The network sends the dedicated preamble as a signal authorizing the UE to proceed with contention-based access using non-dedicated preambles, thereby managing the transition and reducing collision risks through controlled initiation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9572182B2Methods and apparatuses for performing random access in a telecommunication system

Publication Date: 2017.02.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present invention relates to methods and apparatuses (radio base station and UE) for enabling a UE to perform a contention-based random access. According to embodiments of the present invention, a non-dedicated random access preamble identifier is determined by a radio base station and the determined preamble is transmitted in a message to the UE which selects a non-dedicated random access preamble based on the received preamble identifier and performs a contention-based random access using the selected preamble.