Inter-operator Coordination for Shared Spectrum Access

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Solution Overview

Problem

In wireless communications, shared spectrum usage by multiple operators leads to interference and congested networks, particularly when secondary operators lack access to unused resources due to lack of periodic feedback and imperfect transmission beamforming nulling, resulting in lower throughput and channel efficiency.

Innovation Solution

Implementing inter-operator coordination through spatial division multiplexing (SDM) and coordinated multipoint (CoMP) techniques, where the primary cluster broadcasts identification information of APs scheduled for downlink transmissions, allowing the secondary cluster to blacklist stations and selectively schedule transmissions based on spatial characteristics and path loss, thereby reducing interference and optimizing resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple operators share the same spectrum band, then spectrum utilization is improved, but interference between operators increases

Engineering Contradiction:
Improvespectrum utilizationVSAvoidinterference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the shared spectrum resources by spatial domain, dividing the transmission space into different regions. The primary operator transmits in certain spatial directions while the secondary operator transmits in other spatial directions, allowing both operators to utilize the same frequency band simultaneously without causing harmful interference. This is achieved through spatial division multiplexing where different operators are assigned different spatial resources.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension for resource allocation by moving from traditional time-frequency domain multiplexing to spatial domain multiplexing. By utilizing the spatial dimension (third dimension) in addition to time and frequency, the system enables multiple operators to share the spectrum efficiently. The secondary operator accesses unused spatial resources during transmission opportunities, transforming the interference problem into a multi-dimensional resource allocation solution.

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

2Productivity

If the secondary operator attempts to access unused resources, then throughput is improved, but interference management complexity increases

Engineering Contradiction:
ImprovethroughputVSAvoidinterference management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the primary operator broadcasts identification information about its scheduled transmissions to the secondary operator. The secondary operator uses this feedback to identify which spatial resources are unused and can be safely accessed. This feedback loop enables the secondary operator to adjust its transmissions dynamically, accessing unused resources to improve throughput while maintaining manageable interference levels through informed decision-making.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The secondary operator autonomously identifies and accesses unused spatial resources based on the broadcast information from the primary operator. Rather than requiring complex centralized coordination, the secondary operator independently determines which resources are available and utilizes them, improving throughput while keeping interference management complexity manageable through self-service resource allocation.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If beamforming nulling is used to reduce interference, then interference reduction is improved, but reliability decreases due to imperfect nulling

Engineering Contradiction:
Improveinterference reductionVSAvoidtransmission reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

Instead of relying on imperfect beamforming nulling that attempts to suppress interference in a continuous spatial domain, the patent segments the spatial domain into discrete regions assigned to different operators. This segmentation approach provides clear spatial boundaries that eliminate the need for imperfect nulling, thereby maintaining transmission reliability while still achieving interference reduction through spatial separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces broadcast identification information as an intermediary mechanism between the primary and secondary operators. This intermediary provides explicit spatial resource allocation information, replacing the need for direct beamforming nulling between operators. The intermediary enables reliable interference management by clearly defining which spatial resources are available to each operator, eliminating the reliability issues associated with imperfect nulling.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If the primary operator broadcasts identification information, then channel efficiency is improved, but loss of information increases due to broadcast overhead

Engineering Contradiction:
Improvechannel efficiencyVSAvoidbroadcast overhead
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The broadcast identification information contains only the specific spatial resource allocation data that the secondary operator needs to access unused resources. Rather than broadcasting complete transmission details, the system provides localized, targeted information about which spatial regions are available. This reduces broadcast overhead while maintaining channel efficiency by giving the secondary operator precisely the information needed to utilize unused spatial resources effectively.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3695669B1Inter-operator coordination for channel access in shared spectrum
Publication Date: 2024.01.24 QUALCOMM INC
  • EP3695669B1 patent drawingFigure 1
  • EP3695669B1 patent drawingFigure 2
  • EP3695669B1 patent drawingFigure 3

AI summary

Methods, systems, and devices for wireless communications are described. An access point of a secondary cluster may identify a first set of access points of a primary cluster scheduled to perform downlink transmissions over a shared radio frequency spectrum band during a transmission opportunity. The access point may identify a second set of access points and may select a first set of blacklisted stations associated with the secondary cluster for the transmission opportunity. In some cases, the selecting is based on the first set of access points and the second set of access points. The access point may then selectively perform at least one downlink transmission to a second set of stations associated with the secondary cluster during the transmission opportunity. In some examples, the second set of stations is based on the first set of blacklisted stations.