Random Access Preamble Power Control for MTC Coverage Enhancement

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Solution Overview

Problem

The existing random access counter process is not well suited for coverage enhancement (CE) and ramping up to higher CE levels in machine type communication (MTC) devices, leading to inefficient power consumption and potential random access failures.

Innovation Solution

A method and apparatus for a user equipment (UE) and network node that dynamically adjust the transmission power of random access preambles based on the current CE level, incrementing a counter for attempts, and resetting it to ramp up to higher CE levels when the maximum attempts are reached, ensuring appropriate determination of random access failure and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the UE continues to use the existing random access counter process without CE level awareness, then the device complexity is reduced, but the reliability of random access failure determination deteriorates

Engineering Contradiction:

Improvecounter process complexityVSAvoidrandom access failure determination accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces dynamic CE level awareness into the random access counter process. The UE dynamically determines the current CE level and adjusts its behavior accordingly, transitioning from a static counter process to a dynamic one that adapts to coverage conditions. This resolves the contradiction by maintaining simplicity while adding necessary adaptability for reliable failure determination.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of CE level awareness from undefined to defined. By introducing CE level as a new parameter that the UE must determine and report, the system achieves more reliable failure determination without significantly increasing overall device complexity. The counter process remains simple but now operates with enhanced contextual information.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the UE performs excessive random access attempts at higher CE levels, then the coverage enhancement is improved, but the power consumption increases

Engineering Contradiction:

Improvecoverage enhancementVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements feedback mechanisms where the UE reports its CE level to the network node, and the network node uses this information to determine appropriate random access parameters. This feedback loop prevents excessive attempts by aligning UE behavior with network conditions, thereby reducing unnecessary power consumption while maintaining adequate coverage enhancement.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by having the UE determine and report its CE level before initiating the random access procedure. This preliminary determination allows the network to pre-configure appropriate parameters, preventing the UE from making excessive attempts and consuming unnecessary power while still achieving adequate coverage.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If the UE uses a fixed transmission power for random access preambles, then the device complexity is reduced, but the adaptability to different CE levels deteriorates

Engineering Contradiction:

Improvepower control complexityVSAvoidpower adaptation to CE levels

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic power control based on CE level. Instead of using fixed transmission power, the UE dynamically adjusts its power according to the determined CE level. This dynamic approach provides adaptability to different coverage conditions without significantly increasing device complexity, as the power adjustment logic is integrated into the existing random access framework.

Inventive Principle:

Principle #15Dynamics

4Quantity of substance

If the network node does not broadcast CE level information, then the signaling overhead is reduced, but the adaptability of UE random access performance deteriorates

Engineering Contradiction:

Improvesignaling overheadVSAvoidUE random access adaptability

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent applies self-service by having the UE autonomously determine its CE level without requiring explicit network indication. The UE self-evaluates its coverage conditions and reports this determination to the network. This approach reduces signaling overhead while maintaining UE adaptability, as the UE independently assesses its needs without extensive network signaling.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10869337B2Random access coverage enhancement level ramp up procedure

Publication Date: 2020.12.15 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

In one embodiment, a method in a user equipment (UE) for random access (RA) coverage enhancement (CE) is disclosed. The method includes transmitting a random access preamble to a UE, wherein a power of the random access preamble is determined, in part, by a current CE level. The method further includes incrementing a value of a counter by one, wherein the value of the counter indicates a number of random access preambles previously transmitted by the UE. The method may then compare the value of the counter after incrementing its value, to a transmission limit, wherein the transmission limit indicates a maximum number of random access preamble transmission attempts for the current CE level. In response to the counter being equal to the transmission limit plus one, the method includes resetting the value of the counter.