CSI Reporting on PUSCH via Semi-Persistent Scheduling

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Solution Overview

Problem

Current methods for Channel State Indicator (CSI) reporting in LTE wireless telecommunications systems face limitations, including high signaling overhead and limited coverage due to the small size of CSI reports on the Physical Uplink Control Channel (PUCCH) and the need for increased resource allocation signaling on the Physical Downlink Control Channel (PDCCH).

Innovation Solution

Implementing periodic CSI reporting on the Physical Uplink Shared Channel (PUSCH) using semi-persistent scheduling and TTI bundling, where radio resources are allocated for multiple sub-frames, reducing signaling overhead and increasing coverage by including CSI reports in semi-persistent or bundled transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CSI reports are transmitted periodically on PUCCH, then the coverage and reliability of CSI feedback is improved, but the signaling overhead on PUCCH increases and the capacity is limited

Engineering Contradiction:

ImproveCSI feedback reliabilityVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent combines CSI reporting with uplink data transmissions on PUSCH by utilizing granted resources. When the UE receives an uplink grant, it can include CSI reports in the PUSCH transmission, merging two functions (data transmission and channel state feedback) into a single channel, thereby reducing PUCCH overhead while maintaining feedback reliability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The PUSCH channel is made multi-functional by allowing it to carry both uplink data and CSI reports simultaneously. This universal approach enables the same physical channel to serve multiple purposes, reducing the need for dedicated PUCCH resources for CSI feedback

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Quantity of substance

If a-periodic CSI reporting on PUSCH is used, then the signaling overhead is reduced, but the coverage and frequency of CSI feedback decreases

Engineering Contradiction:

Improvesignaling overheadVSAvoidCSI feedback frequency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent implements a dynamic CSI reporting mechanism where the UE switches between periodic PUCCH reporting and a-periodic PUSCH reporting based on uplink grant availability. This dynamic adaptation allows the system to maintain high feedback frequency when resources are available while reducing signaling overhead when they are not

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent establishes periodic opportunities for CSI reporting on PUSCH by configuring periodic uplink grants or semi-persistent scheduling. This creates regular intervals where CSI can be reported on PUSCH, maintaining feedback frequency similar to periodic PUCCH reporting while utilizing the more flexible PUSCH channel

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If the PUCCH is used for both CSI reports and other control information, then the control channel utilization is improved, but the capacity for CSI reporting is limited

Engineering Contradiction:

Improvecontrol channel utilizationVSAvoidCSI report size

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments the control information transmission by separating CSI reporting from other control signals. While PUCCH handles scheduling requests and HARQ feedback, CSI reporting is segmented to occur on PUSCH when uplink grants are available, dividing the control plane traffic to avoid capacity constraints

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent moves CSI reporting from the control plane (PUCCH) to the data plane (PUSCH), changing the dimensional space where CSI transmission occurs. This allows CSI reports to leverage the larger capacity of the shared channel while PUCCH maintains its specialized function for critical control information

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3605936B1Methods and arrangements in a telecommunications system

Publication Date: 2021.05.05 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

The present invention relates to allowing configuring CSI reporting (step S-224, 310) on radio resources that are allocated over a plurality of sub frames on Physical Uplink Shared Channel (PUSCH). Allocation of said radio resources (steps S-202, 404) can be performed by semi-persistent allocation or by using Transmission Time Interval (TTI) bundling. By using either semi-persistent scheduling or TTI-bundling as decided by an eNB (104, 204, 600) the UE (102, 202, 500) can be configured to report CSI (step S-224, 310) for a plurality of UL transmissions. By allocating radio resources by using semi-persistent scheduling, the signaling overhead, which can be substantial for dynamic scheduling of radio resources, decreases. By using TTI-bundling the coverage of the CSI-reports increases.