Random Access Procedure Reliability via Neighboring Node Assistance

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Solution Overview

Problem

The existing random access procedure in radio access networks is not robust, leading to lost requests from User Equipment (UE) and requiring cumbersome retransmissions with increased power, as it lacks effective mechanisms for ensuring reliable communication between UE and radio access nodes.

Innovation Solution

The method involves two radio access nodes with different sets of signature sequences to differentiate requests, where the first node receives and responds to a random access request, and optionally requests the second node to respond if the signal is weak or lost, ensuring diversity and reliability by sharing signature sequences and coordinating responses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If unique preamble sequences are used between two neighbour base stations, then only the base station that matches the preamble sequence will respond, but the procedure lacks robustness and requests may get lost requiring cumbersome retransmissions

Engineering Contradiction:
Improverobustness of random access procedureVSAvoidcomplexity of retransmission procedure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functionality of multiple base stations by allowing a second base station to assist the first base station in responding to random access requests. When the first base station determines it cannot respond (due to signal loss or overload), it requests assistance from the second base station, which then sends the random access response on behalf of the first base station. This combining of resources resolves the contradiction by improving reliability through redundancy while avoiding the complexity of traditional retransmission procedures.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a base station receives a random access request but cannot respond due to signal loss or overload, then retransmission with higher power is required, but this increases the cumbersome nature of the procedure

Engineering Contradiction:
Improvesuccessful delivery of random access responseVSAvoidtime for retransmission
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary action by having the second base station stand by in readiness to assist before any signal loss or overload occurs. The base stations exchange capability information in advance, so when the first base station determines it cannot respond, the second base station is already prepared to immediately send the random access response. This eliminates the need for time-consuming retransmission cycles with power increases, as the backup response is ready beforehand.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If a base station responds to all received random access requests, then responsiveness is improved, but interference to other UEs may increase

Engineering Contradiction:
Improveresponsiveness to random access requestsVSAvoidinterference to other UEs
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by allowing different base stations to have different response behaviors based on their local conditions. The first base station evaluates its own signal quality and load conditions, and only requests assistance from the second base station when it determines it cannot properly respond. This localized decision-making ensures that base stations respond to requests when capable (maintaining responsiveness) while avoiding responses that would cause interference or overload (reducing harmful factors).

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3539344B1A method and devices of performing a random access procedure between a user equipment, UE, and a radio access network of a telecommunication network
Publication Date: 2024.08.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3539344B1 patent drawingFigure 1~2
  • EP3539344B1 patent drawingFigure 3~4
  • EP3539344B1 patent drawingFigure 5

AI summary

Method of performing a random access procedure between a User Equipment, UE, and a radio access network, wherein two access nodes comprise different sets of signature sequences, wherein said signature sequences are used, by said access nodes, to differentiate requests coming from different UEs, said method comprising the steps of receiving a random access request from said UE, wherein said random access request comprises a signature sequence, determining that said random access request is intended for said first radio access node based on said signature sequence comprised by said request, receiving, from a second access node, said random access request, thereby indicating that said second radio access node has also received said random access request from said UE, and sending a response based on said received random access request from said U E and based on said random access request received from said second radio access node.