CSI Reporting Modes for MTC Devices

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Solution Overview

Problem

Conventional CSI reporting modes do not adequately support low complexity, coverage enhanced Machine-Type Communication (MTC) devices, which often have single receiving antennas and operate with specific coverage enhancement modes, including frequency hopping.

Innovation Solution

Define CSI reporting modes that vary based on whether frequency hopping is enabled or a selected coverage enhancement (CE) mode is used, specifically for low complexity and coverage enhanced MTC devices, including modified aperiodic and periodic reporting modes for PUSCH and PUCCH channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional CSI reporting modes are used, then the reporting process is simple, but low complexity MTC devices with single receiving antennas and coverage enhancement modes cannot be adequately supported

Engineering Contradiction:
Improvesupport for MTC devicesVSAvoidreporting mode complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic CSI reporting modes that adapt to different MTC device configurations. The network configures specific reporting modes based on whether the device uses frequency hopping or coverage enhancement, allowing the system to dynamically adjust reporting behavior to match device capabilities and operational modes rather than using a static conventional approach

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies different CSI reporting strategies tailored to specific MTC device characteristics. Devices using frequency hopping receive one optimized reporting configuration, while devices using coverage enhancement receive another optimized configuration, ensuring each device type gets the appropriate level of support without unnecessarily complicating the overall system

Inventive Principle:
Principle #3Local quality

2Reliability

If frequency hopping is enabled for MTC devices, then coverage is enhanced, but conventional CSI reporting modes cannot properly report channel conditions across frequency bands

Engineering Contradiction:
Improvecoverage enhancementVSAvoidchannel condition reporting accuracy
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent segments the frequency spectrum into multiple bands and implements separate CSI reporting mechanisms for each band when frequency hopping is enabled. This allows the device to report channel conditions for each frequency band individually, capturing the varying channel quality across different frequencies rather than losing information about specific band conditions

Inventive Principle:
Principle #1Segmentation

3Device complexity

If reduced UE bandwidth of 1.4 MHz is used for low complexity MTC devices, then device cost is reduced, but the devices can only receive a part of the total system bandwidth at a time

Engineering Contradiction:
ImproveUE bandwidth reductionVSAvoiddata reception capability
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements periodic CSI reporting where low complexity MTC devices report channel state information at regular intervals on the reduced 1.4 MHz bandwidth. This periodic reporting mechanism allows the network to maintain accurate channel knowledge despite the device's limited bandwidth, enabling efficient scheduling and resource allocation that maximizes data reception capability within the constraints of reduced device bandwidth

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3371911B1CSI report for MTC operation
Publication Date: 2020.05.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3371911B1 patent drawingFigure 1
  • EP3371911B1 patent drawingFigure 2
  • EP3371911B1 patent drawingFigure 3

AI summary

According to some embodiments, a method of reporting a channel quality indicator (CQI) comprises receiving, in a wireless network comprising a carrier bandwidth of a first number of physical resource blocks (PRBs), a physical channel comprising a first PRB set with a bandwidth of a second number of PRBs. The second number of PRBs is less than the first number of PRBs. The method further comprises determining a CQI that indicates a modulation and code rate of the physical channel that may be used to transmit the physical channel with a transport block error probability not exceeding 0.1 when the physical channel is transmitted in the second number of PRBs of the first PRB set in a subframe and at least part of the transport block is transmitted in the subframe. The method further comprises transmitting a report to a network node. The report comprises the determined CQI.