Implicit Repetition Level Signaling for MTC Control Channels

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Solution Overview

Problem

In Machine-Type Communication (MTC) systems, particularly in LTE, there is a challenge in accurately determining the repetition level of Enhanced Physical Downlink Control Channel (E)PDCCH signals, leading to potential misunderstandings by User Equipments (UEs) about the start of scheduled Physical Downlink Shared Channel (PDSCH) transmissions, which can result in incorrect decoding of PDSCH.

Innovation Solution

The method involves processing data through at least five processes: cyclic redundancy check attachment, channel coding, rate matching, modulation, and resource element mapping, and transmitting these signals with different repetition levels, where the repetition level is implicitly indicated by varying the number of subframes (Ri) for each level, avoiding additional signaling costs and ambiguity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If repetition levels are indicated using additional signaling, then the accuracy of repetition level determination is improved, but the signaling cost and system complexity increase

Engineering Contradiction:

Improverepetition level determination accuracyVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The system uses self-service by deriving repetition level information from existing signal characteristics rather than external signaling. The UE determines repetition level by analyzing the number of received repetitions and applying predefined mapping rules, making the system self-determining without additional network signaling.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent changes the parameter being signaled from explicit repetition level indicators to implicit indicators based on signal characteristics. By mapping repetition counts to coverage enhancement levels and corresponding PDSCH timing offsets, the system encodes multiple pieces of information through parameter relationships rather than direct signaling.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If multiple repetition levels are supported with different Ri values, then the adaptability to different coverage requirements is improved, but the device complexity increases

Engineering Contradiction:

Improvecoverage requirement adaptabilityVSAvoidrepetition level management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system manages multiple repetition levels by changing parameters such as subframe offsets and timing relationships rather than creating separate transmission paths. Each repetition level associates with specific PDSCH timing offsets and subframe configurations, allowing the same physical resources to serve multiple coverage requirements through parameter variation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements multi-functionality by using a unified (E)PDCCH transmission framework that serves multiple coverage enhancement levels. The same control channel structure and processing procedures handle different repetition levels, with differentiation achieved through parameter mapping rather than separate system components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the number of subframes for transmission is increased for better coverage, then the coverage enhancement is improved, but the transmission time delay increases

Engineering Contradiction:

Improvecoverage enhancementVSAvoidtransmission time delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system applies preliminary action by pre-configuring PDSCH timing offsets and subframe relationships for different repetition levels. The UE is provided with mapping information that allows it to determine when to expect PDSCH transmissions based on the number of (E)PDCCH repetitions received, enabling timely reception without extending the overall transmission window.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making PDSCH timing flexible and adaptive to the actual repetition level detected. Rather than fixed timing, the system dynamically adjusts PDSCH start timing based on the relationship between repetition count and configured offsets, allowing the transmission schedule to adapt to channel conditions and coverage requirements.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10009885B2Method and device for transmitting data at different repetition levels, and method and device for receiving data at different repetition levels

Publication Date: 2018.06.26 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

A method and device for transmitting data and a method and device for receiving data are provided. The method for transmitting data comprises: processing the data in at least five processes of cyclic redundancy check attachment, channel coding, rate matching, modulation and resource element mapping to generate a signal; and transmitting the signal in a plurality of subframes with a repetition level i, wherein the repetition level i is selected from a repetition level set including at least two different repetition levels, and for repetition level i, the data are transmitted in Ri subframes, and for different repetition levels, values of Ri are different, and wherein the data are processed by the five processes or by the five processes and at least one additional process to generate different signals to be transmitted according to different repetition levels.