CSI Reporting Offset for Heterogeneous Network Subframes

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Solution Overview

Problem

In heterogeneous cellular networks, existing CSI reporting mechanisms are inefficient due to the need to extend CSI report grants with additional bits to account for different subframe types, leading to increased overhead and potential degradation in system operations, especially in link imbalance zones where interference varies significantly.

Innovation Solution

A method where user equipment determines the subframe type based on a grant received from the base station, allowing it to report CSI reflecting channel conditions in specific subframe types, eliminating the need for additional bits by using a variable value p to align CSI reports with protected or non-protected subframes, thereby improving reporting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If CSI report grants are extended with additional bits to account for different subframe types, then reporting accuracy for heterogeneous networks is improved, but overhead increases and system operations may degrade

Engineering Contradiction:
ImproveCSI reporting accuracyVSAvoidCSI report grant overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies local quality by making the CSI reporting mechanism adaptive to different subframe types. Instead of using a uniform reporting approach for all subframes, the system selectively applies different reporting behaviors based on whether the subframe is protected or non-protected. This allows the grant structure to be optimized locally for each subframe type, achieving accurate reporting where needed while minimizing overhead in other cases.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by introducing a variable offset value that dynamically adjusts the CSI reporting timing based on subframe type. The offset is not fixed but adapts according to whether the subframe is protected or non-protected, allowing the system to flexibly respond to changing network conditions and interference patterns without requiring static grant extensions.

Inventive Principle:
Principle #15Dynamics

2Loss of information

If CSI reporting covers all subframe types, then comprehensive channel state information is obtained, but reporting efficiency decreases due to unnecessary overhead in link imbalance zones

Engineering Contradiction:
Improvechannel state information completenessVSAvoidCSI reporting efficiency
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The patent applies the extraction principle by selectively removing unnecessary CSI reporting requirements for certain subframe types. In link imbalance zones, the system extracts only the essential CSI information from protected subframes while omitting redundant reporting for non-protected subframes where interference patterns are predictable or less critical. This maintains information completeness for decision-making while eliminating wasteful overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements partial action by requiring CSI reporting only for specific subframe types rather than all subframes. Instead of performing excessive reporting across every subframe, the system applies partial reporting requirements focused on the most informative subframes, achieving sufficient channel state knowledge with reduced signaling overhead and improved reporting efficiency.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If heterogeneous networks use different output powers for macro and pico cells, then system capacity is improved through cell splitting, but interference situation becomes more complex and difficult to manage

Engineering Contradiction:
Improvesystem capacityVSAvoidinterference management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the interference management approach into distinct segments for protected and non-protected subframes. Different CSI reporting requirements are assigned to different subframe types, creating segmented interference management strategies that address the unique characteristics of each subframe category. This segmentation simplifies the overall complexity by breaking down the heterogeneous interference problem into manageable, type-specific handling rules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by pre-configuring offset values and reporting requirements for different subframe types before actual CSI reporting occurs. The system establishes predetermined rules for protected versus non-protected subframes, allowing user equipment to automatically adapt its reporting behavior without real-time complex decision-making. This preliminary configuration reduces runtime complexity while maintaining effective interference management.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10097332B2Method and arrangement in a telecommunication system
Publication Date: 2018.10.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US10097332B2 patent drawing
  • US10097332B2 patent drawing
  • US10097332B2 patent drawing

AI summary

A method and an arrangement in a user equipment for reporting Channel State Information, CSI, and a method and an arrangement in a base station for obtaining CSI are provided. The user equipment is in connection with the base station in a cellular communication network. After receiving a receiving a grant in a subframe n to be used for CSI reporting, from the base station, the user equipment determines subframe type of a subframe n+p. The user equipment then reports to the base station, CSI reflecting channel conditions in the subframe type of subframe n+p. p is a variable value.