Aggregation Level Specific PDCCH Modification for 5G

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Solution Overview

Problem

In wireless communication systems, particularly in NR (New Radio) and 5G technologies, there is an ambiguity issue when a higher aggregation level control message can be decoded as a lower aggregation level message, leading to difficulties for user equipment (UE) in determining resource allocations, which affects the accurate decoding of physical downlink shared channels (PDSCH) and uplink control channel (PUCCH) allocations.

Innovation Solution

The solution involves modifying the coded bits of the physical downlink control channel (PDCCH) message in an aggregation level-specific manner, ensuring that the decoding candidates for different aggregation levels do not overlap, and using techniques like cyclic rotation, inversion, or scrambling to prevent ambiguity, allowing the UE to correctly identify the aggregation level used for transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If decoding candidates for different aggregation levels overlap in time and frequency resources, then resource utilization efficiency is improved, but ambiguity in determining the aggregation level occurs

Engineering Contradiction:

Improveresource utilization efficiencyVSAvoidaggregation level determination accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies bit inversion as a transformation technique to differentiate PDCCH messages transmitted at different aggregation levels. Specifically, when a PDCCH message is transmitted at aggregation level 4 or 8, certain bits in the message are inverted (flipped from 0 to 1 or vice versa). This creates a detectable pattern that allows the UE to determine the aggregation level used, even when decoding candidates overlap in time and frequency resources. The inversion acts as a marker that changes the 'color' or state of the message bits based on the aggregation level.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent modifies parameters of the PDCCH message itself to encode aggregation level information. By inverting specific bits in the message payload or control information, the system changes the message parameters in an aggregation level-dependent manner. This allows the receiving UE to detect the aggregation level by examining the inverted bits, thereby resolving the ambiguity that would otherwise exist when decoding candidates overlap.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If PDCCH messages are transmitted with higher aggregation levels to improve reliability, then transmission robustness is improved, but resource overhead increases

Engineering Contradiction:

Improvetransmission robustnessVSAvoidresource overhead

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies partial action by inverting only specific bits in the PDCCH message rather than all bits. This selective inversion provides sufficient information for aggregation level determination while minimizing the impact on message payload and resource usage. The technique uses just enough modification (inverting key indicator bits) to achieve the goal of aggregation level identification without excessive resource consumption.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10904871B2Aggregation level specific PDCCH modification

Publication Date: 2021.01.26 QUALCOMM INC

AI summary

Certain aspects of the present disclosure relate to methods and apparatus for aggregation level specific PDCCH modification.