SDMA Carrier Sharing for Multi-RAT Spectrum Efficiency

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Solution Overview

Problem

Existing cellular communication systems are less than optimal for spectrum sharing between Radio Access Technologies (RATs), particularly when one RAT has few user devices, limiting spatial multiplexing gains and spectral efficiency, especially with the advent of 5G RATs that use Advanced Antenna Systems for Massive MIMO operations.

Innovation Solution

Implementing a carrier/spectrum sharing scheme that utilizes spatial multiplexing across multiple RATs, allowing for joint scheduling and resource management to exploit spatial user multiplexing opportunities, thereby increasing spectral efficiency and energy performance by sharing frequency bands effectively across all RATs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional time and frequency multiplexing is used for spectrum sharing between RATs, then existing systems work well for sharing single carrier, but spectral efficiency is limited when one RAT has few user devices

Engineering Contradiction:
Improvespectral efficiencyVSAvoidspatial multiplexing capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent extends spectrum sharing from traditional time and frequency domains into the spatial domain by implementing SDMA carrier sharing. This allows multiple RATs to simultaneously share the same time-frequency resources by spatially separating user devices through beamforming and advanced antenna systems, thereby resolving the limitation of low spectral efficiency when one RAT has few users.

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

2Productivity

If full carrier bandwidth is dedicated to a legacy RAT, then the legacy RAT is well supported, but spectrum cannot be efficiently shared with 5G RAT

Engineering Contradiction:
Improvespectrum utilization efficiencyVSAvoidlegacy RAT support quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a multi-RAT carrier sharing mechanism that allows a single carrier to serve multiple RATs (LTE and 5G NR) simultaneously through spatial multiplexing. The system can dynamically allocate resources to different RATs based on demand, enabling the same carrier to function for both legacy and advanced RATs without dedicated bandwidth allocation, thus improving overall spectrum utilization while maintaining legacy support.

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

3Productivity

If spatial multiplexing is not exploited across RATs, then system complexity is lower, but spectral efficiency and energy performance are suboptimal

Engineering Contradiction:
Improvespectral efficiencyVSAvoidjoint scheduling complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the scheduling functions of multiple RATs into a unified joint scheduling framework. By combining resource allocation, beamforming, and spatial multiplexing control into a single coordinated system, the patent enables efficient exploitation of spatial user multiplexing opportunities across RATs, improving spectral efficiency and energy performance while managing complexity through integrated control.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3804436B1SDMA carrier sharing
Publication Date: 2024.08.07 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3804436B1 patent drawingFigure 1
  • EP3804436B1 patent drawingFigure 2
  • EP3804436B1 patent drawingFigure 3

AI summary

Systems and methods are disclosed herein for scheduling wireless communication devices in a wireless communication system in accordance with a carrier or spectrum sharing scheme that utilizes spatial multiplexing across Radio Access Technologies (RATs).