PDCCH Single-Carrier Control Channel With Hierarchical DCI Spreading

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Solution Overview

Problem

The challenge with single carrier modulation using PDCCH is the varying number of DCIs conveyed within a CORESET, leading to deteriorating power efficiency when multiple DCIs are scheduled.

Innovation Solution

Implement hierarchical spreading of modulated DCI symbol sequences with equal size, followed by DFT and IFFT, ensuring all DCIs have equal size and are efficiently transmitted using hierarchical spreading codes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If single carrier modulation is used with PDCCH to convey control information, then power efficiency is improved, but the varying number of DCIs conveyed within a CORESET causes power efficiency to deteriorate when multiple DCIs are scheduled

Engineering Contradiction:

Improvepower efficiencyVSAvoidnumber of DCIs conveyed

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The control information is segmented into multiple DCI messages of equal size, each assigned a unique spreading code from the hierarchical spreading code set. This segmentation allows multiple DCIs to be conveyed simultaneously while maintaining equal size for power efficiency, resolving the contradiction between conveying multiple DCIs and maintaining power efficiency under single carrier modulation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of DCI size from variable to fixed/equal size by using hierarchical spreading codes. Each DCI message is padded or truncated to match a standard size, and spreading codes provide the necessary differentiation. This parameter change enables multiple DCIs to be transmitted efficiently under single carrier modulation while maintaining consistent power efficiency

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If hierarchical spreading is applied to equalize DCI sizes, then power efficiency is maintained, but the complexity of the transmission system increases

Engineering Contradiction:

Improvepower efficiencyVSAvoidsystem complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The hierarchical spreading codes serve multiple functions simultaneously: they equalize DCI sizes for power efficiency, provide unique identification for each DCI message, and enable orthogonal multiplexing of multiple DCIs. This multi-functionality reduces the need for separate mechanisms, thereby limiting the increase in system complexity while achieving power efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The spreading codes are predetermined and assigned to different DCI messages before transmission. The equalization of DCI sizes and assignment of spreading codes is performed in advance, which simplifies the real-time transmission process and reduces the operational complexity of the system while maintaining power efficiency

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4026383B1Single carrier control channel

Publication Date: 2026.02.25 NOKIA TECHNOLOGIES OY

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AI summary

A spreading sequence is determined (S301) based on a candidate of a control channel of a control resource set, the candidate comprising a sequence of control information. The sequence of control information and the determined spreading sequence are multiplied (S303), thereby obtaining a spread series of control information.