xPDCCH Control Resource Allocation to Reduce Signaling Overhead

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Solution Overview

Problem

Current wireless communication systems face inefficiencies in spectral efficiency due to high control channel overhead and limitations in hybrid beamforming architectures, particularly in scenarios where uplink control plane bottlenecks occur.

Innovation Solution

The system is modified to allocate control and data resources dynamically, allowing for multiple xPDCCH symbols with low load, and uses separate DCI formats to optimize resource usage, enabling multiplexing of control and data within the same symbol.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional control channel allocation is used, then control signaling is provided, but spectral efficiency deteriorates due to high control overhead

Engineering Contradiction:
Improvecontrol signalingVSAvoidspectral efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the control channel into multiple parts: traditional PDCCH for common control information, and new xPDCCH resources for user-specific control information. This segmentation allows control and data to coexist in different time-frequency regions, reducing overall control overhead while maintaining reliable control signaling delivery.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension for control signaling by allocating xPDCCH in the uplink direction (reverse link) rather than only in the downlink control region. This dimensional change allows control information to be transmitted alongside data in the uplink, significantly reducing downlink control overhead and improving spectral efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If more control symbols are allocated, then control capacity increases, but data throughput decreases

Engineering Contradiction:
Improvecontrol capacityVSAvoiddata throughput
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent uses the uplink shared channel (PUSCH) as an intermediary to carry both data and user-specific control information (xPDCCH) simultaneously. This intermediary approach allows control capacity to be increased without reducing data throughput, as control information is embedded within the uplink data transmission rather than occupying separate downlink resources.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If hybrid beamforming architecture is used, then beamforming capability is improved, but uplink control plane becomes a bottleneck

Engineering Contradiction:
Improvebeamforming capabilityVSAvoiduplink control plane
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the uplink shared channel serve multiple functions: carrying both data traffic and user-specific control information (xPDCCH). This multi-functionality reduces the burden on the uplink control plane, eliminating the bottleneck created by hybrid beamforming architecture while maintaining beamforming capability for data transmission.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3491769B1On the usage of control resources for data transmission
Publication Date: 2025.07.30 NOKIA TECHNOLOGIES OY
  • EP3491769B1 patent drawingFigure 1
  • EP3491769B1 patent drawingFigure 2
  • EP3491769B1 patent drawingFigure 3

AI summary

A method, apparatus, and computer program product modifying the usage of control resources for data transmission by focusing on reducing overhead of the control channel in order to maximize the spectral efficiency by configuring physical resources into two parts for an allocation into control information for the first part, and data for both the first part and the second part or data for only the second part. Data allocation in the first part based is derived based on the data allocation in the second part and the control information allocation in the first part. The number of control symbols within a subframe or transmission time interval is minimized on the downlink control signaling, used mainly for downlink and uplink grant signaling, and for the uplink HARQ ACK/NACK feedback. Where overhead is not the only problem, usage of two symbols is proposed due to the limitations of radio frequency beamforming.