Virtual MIMO Array for CoMP Backhaul Bandwidth Reduction

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Solution Overview

Problem

Current wireless communication networks face challenges in improving spectral efficiency due to inter-cell interference and high backhaul bandwidth requirements for Coordinated Multi-Point (CoMP) transmission, which limits system throughput and increases costs.

Innovation Solution

Implementing spatial device-to-device (D2D) multiplexing and joint CoMP transmission and reception, forming virtual multi-input multi-output (MIMO) arrays to cluster wireless devices and reduce backhaul bandwidth needs by retransmitting signals within local device-to-device clusters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If joint CoMP transmission with multiple base stations is implemented, then spectral efficiency and system throughput are improved, but backhaul bandwidth requirements increase significantly

Engineering Contradiction:
Improvesystem throughputVSAvoidbackhaul bandwidth
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent segments the CoMP transmission function into two parts: local D2D spatial multiplexing is performed within device clusters using local device resources, while joint CoMP processing is performed only for aggregated data at the base station. This segmentation allows spectral efficiency gains from spatial multiplexing without requiring all base stations to exchange full user data over the backhaul, thus reducing backhaul bandwidth requirements while maintaining improved system throughput.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces device-to-device (D2D) communication as an intermediary layer between user equipment and base stations. Devices within a cluster perform local spatial multiplexing and aggregate data before transmitting to the base station. This intermediary approach enables the benefits of coordinated multi-point processing while avoiding the need for high-bandwidth backhaul connections between all participating base stations, as only aggregated results need to be transmitted.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If aggressive radio resource reuse in neighboring cells is implemented, then spectral efficiency is improved, but inter-cell interference increases

Engineering Contradiction:
Improvespectral efficiencyVSAvoidinter-cell interference
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent merges signals from multiple devices within a cluster using virtual MIMO techniques, where devices cooperate to transmit combined signals to the base station. This merging approach allows aggressive resource reuse in neighboring cells because the coordinated transmission from multiple devices creates constructive interference at the intended receiver while maintaining spectral efficiency, effectively converting what would be harmful inter-cell interference into useful signal energy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent converts inter-cell interference into a beneficial effect by implementing joint CoMP processing where signals from multiple base stations and devices are combined constructively. Instead of treating interference as harmful noise to be eliminated, the system coordinates transmissions so that signals from neighboring cells and devices arrive in phase at the intended receiver, transforming the harmful interference into enhanced signal strength and improved spectral efficiency.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If virtual MIMO arrays are formed with multiple wireless devices, then spatial multiplexing gains are achieved, but device complexity and coordination overhead increase

Engineering Contradiction:
Improvespectral efficiencyVSAvoidcoordination overhead
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements self-service mechanisms where devices within a cluster autonomously perform local spatial multiplexing and data aggregation using distributed algorithms. Each device independently determines its transmission parameters and coordinates with neighboring devices through lightweight signaling, rather than requiring centralized control from the base station. This self-organization approach achieves spectral efficiency gains from virtual MIMO while minimizing coordination overhead and device complexity by leveraging local device intelligence.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3141041B1System and method implementing spatial multiplexing and joint coordinated multipoint transmission of data
Publication Date: 2019.07.31 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3141041B1 patent drawingFigure 1
  • EP3141041B1 patent drawingFigure 2
  • EP3141041B1 patent drawingFigure 3

AI summary

According to some embodiments, a method in a wireless communication device includes exchanging, with all wireless devices within a cluster of wireless devices, data to be transmitted to each serving node serving a wireless device within the cluster of wireless devices. The cluster is formed based on one or more metrics. The data exchanged with all wireless devices in the cluster is concatenated into a multiplexed data block. A virtual multi- input multi-output (VMIMO) array is formed with the antennas of all wireless devices within the cluster, and the VMIMO array is used to transmit the multiplexed data block.