PUCCH Repetition Determination via PRACH CE Level Mapping

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Solution Overview

Problem

In wireless communication technology, particularly for Machine-Type Communication (MTC) in LTE, there is a need to enhance control information transmission flexibility and reliability, especially for the uplink, as existing methods lack efficient mechanisms for determining the number of PUCCH repetitions without additional signaling, especially during the initial access stage when UE-specific RRC parameters are not yet established.

Innovation Solution

The solution involves implicitly determining the number of PUCCH repetitions based on the number of repetitions of other physical channels, such as PUSCH or MPDCCH, using mapping tables and criteria like MCS/TBS index or PRACH CE level, allowing the UE to configure PUCCH without explicit signaling, thereby enabling robust and flexible control information transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the number of PUCCH repetitions is determined without additional signaling, then the device complexity and signaling overhead are reduced, but the reliability and precision of determining the repetition number in different coverage scenarios deteriorates

Engineering Contradiction:

Improvesignaling overheadVSAvoiddetermination precision of PUCCH repetitions

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The network pre-configures mapping tables that associate PUSCH/MPDCCH repetition numbers with corresponding PUCCH repetition numbers. These mapping tables are stored in the UE beforehand, allowing the UE to determine PUCCH repetitions by simply looking up the mapping based on detected PUSCH/MPDCCH repetitions, without needing additional signaling during initial access.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Mapping tables serve as an intermediary mechanism between PUSCH/MPDCCH transmissions and PUCCH repetitions. Instead of directly signaling PUCCH repetition numbers, the system uses these tables to translate observed PUSCH/MPDCCH repetition patterns into appropriate PUCCH repetition counts, enabling indirect but accurate determination.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If UE-specific RRC parameters are established before initial access, then the adaptability of control information transmission is improved, but the productivity and access speed deteriorate

Engineering Contradiction:

Improveadaptability of control information transmissionVSAvoidinitial access speed

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The system pre-configures mapping tables and determination criteria in the UE before initial access occurs. These include mappings between PUSCH/MPDCCH repetition numbers and PUCCH repetition numbers, as well as criteria based on MCS/TBS indexes and PRACH CE levels. This preliminary configuration enables the UE to immediately determine appropriate PUCCH repetitions during initial access without waiting for RRC parameter establishment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The UE autonomously determines the number of PUCCH repetitions by applying pre-configured mapping tables and criteria to observed PUSCH/MPDCCH transmissions. This self-service mechanism eliminates the need for network signaling during initial access, allowing the UE to independently configure appropriate PUCCH repetitions and proceed with access procedures immediately.

Inventive Principle:

Principle #25Self-service

3Device complexity

If the number of PUCCH repetitions is fixed, then the device complexity is reduced, but the adaptability to different coverage scenarios deteriorates

Engineering Contradiction:

Improveconfiguration complexityVSAvoidadaptability to coverage scenarios

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The network provides the UE with pre-configured mapping tables that cover multiple PUSCH/MPDCCH repetition scenarios and corresponding PUCCH repetition recommendations. These tables are prepared in advance to handle various coverage conditions, enabling the UE to adapt to different scenarios by selecting the appropriate mapping based on observed repetitions without complex real-time configuration.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system enables dynamic adaptation of PUCCH repetitions based on observed PUSCH/MPDCCH repetition patterns. The UE monitors the number of PUSCH/MPDCCH repetitions received and dynamically determines the corresponding PUCCH repetition number using pre-configured mappings, allowing flexible adaptation to changing coverage conditions while maintaining relatively simple device logic.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP3411976B1Methods for determining the number of repetitions of pucch for MTC ues

Publication Date: 2021.06.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

The disclosure pertains to a terminal for a Radio Access Network, the terminal being adapted for transmitting Uplink Control Information, UCI. Transmitting UCI comprises repeating the UCI for a number of repetitions, the number of repetitions being determined based on a Random Access CHannel Coverage Enhancement Level, PRACH CE level. The disclosure also pertains to related methods and devices.