Dynamic PRACH Preamble Configuration for Wireless Access

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Solution Overview

Problem

Current wireless communication networks face performance issues due to static preamble length configurations in the physical random-access channel (PRACH), which result in either poor performance with high received signal energy or higher capacity with worse performance, depending on the preamble length chosen.

Innovation Solution

A method and apparatus that dynamically determine the preamble configuration parameters, including length, subframe configuration, sequence configuration, and frequency resources, based on signal strength and network load measurements, allowing the radio-network node to transmit these parameters to the wireless device for an optimized random-access procedure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a long preamble is used in PRACH, then the received signal energy is high, but the network capacity is reduced

Engineering Contradiction:
Improvereceived signal energyVSAvoidnetwork capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the preamble length adjustable rather than fixed. The radio-network node dynamically selects between short and long preamble configurations based on real-time network load conditions, allowing the system to adapt its characteristics to current operational requirements rather than being constrained by a static configuration

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the physical parameter of preamble length based on network conditions. By modifying this parameter dynamically - using long preambles when network load is low (to ensure high received signal energy) and short preambles when network load is high (to maximize network capacity) - the system optimizes the trade-off between reliability and productivity

Inventive Principle:
Principle #35Parameter changes

2Productivity

If a short preamble is used in PRACH, then the network capacity is high, but the received signal energy is low

Engineering Contradiction:
Improvenetwork capacityVSAvoidreceived signal energy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system dynamically adjusts preamble length based on network load, switching to short preambles during high-load conditions to maximize network capacity while accepting the trade-off of reduced received signal energy, and switching to long preambles during low-load conditions to ensure adequate signal energy

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent modifies the preamble length parameter in response to changing network conditions, allowing the system to optimize for network capacity when load is high by using short preambles, and optimize for signal energy when load is low by using long preambles

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If static preamble configuration is used, then the system is simple to implement, but the network performance is poor under varying load conditions

Engineering Contradiction:
Improveimplementation simplicityVSAvoidnetwork performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces dynamic adaptation to network load conditions while maintaining relatively simple implementation. The radio-network node monitors network load and automatically selects appropriate preamble configurations, providing performance optimization without requiring complex manual configuration or intervention

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs self-configuration by automatically adjusting preamble length based on its own monitoring of network load conditions. The radio-network node independently determines the appropriate preamble configuration without external intervention, optimizing performance while keeping the system simple to implement

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3440888B1Radio-network node, wireless device and methods performed therein
Publication Date: 2021.07.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3440888B1 patent drawingFigure 1a
  • EP3440888B1 patent drawingFigure 1b
  • EP3440888B1 patent drawingFigure 2

AI summary

Embodiments herein relate to a method performed by a radio-network node (12) for handling access to the radio-network node (12) from a wireless device (10) in the wireless communication network (1). The radio-network node determines one or more preamble configuration parameters indicating a length of a preamble for a physical random-access channel, PRACH, for the wireless device (10) based on one or more signal strength or quality measurements, and/or a load in the wireless communication network (1). The radio network node further transmits an indication of the determined one or more preamble configuration parameters to the wireless device.