Outdoor-Indoor MIMO Repeaters with Leaky Cables
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Solution Overview
Problem
Existing outdoor-indoor MIMO communication systems face challenges in providing good indoor coverage with high bit-rate and spectrally efficient communication due to penetration loss through building walls and limited spatial separation of repeater antennas, leading to high correlation and power imbalances.
Innovation Solution
A wireless MIMO communication system with well-separated outdoor-indoor repeaters and dual-polarized leaky cables, where repeaters are spaced apart to support a rank equal to the number of antennas, providing uniform indoor coverage and extending channel rank for improved spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeater antennas are placed in line of sight to ensure good link quality, then communication signal strength is improved, but spatial separation is limited leading to high correlation and reduced MIMO gains
Solution Approach 1:
The system divides the repeater functionality into multiple spatially separated repeater units, each with its own antenna elements. This segmentation allows the repeaters to be positioned far apart (e.g., at different locations on the building exterior) while maintaining line-of-sight connectivity to the base station, thereby achieving both good link quality and high MIMO channel rank simultaneously
Solution Approach 2:
The patent utilizes three-dimensional spatial distribution by positioning repeaters at different locations on the building exterior (e.g., different floors, walls, or angles). This vertical and spatial distribution in multiple dimensions enables sufficient separation between antenna elements while maintaining LOS to the base station, resolving the contradiction between link quality and MIMO capability
2Area of stationary object
If donor antennas are co-located with repeater to provide indoor coverage, then coverage is improved, but power imbalance occurs when communicating with users closer to one donor antenna, reducing MIMO gains
Solution Approach 1:
Instead of using a single co-located donor antenna, the system employs multiple donor antennas distributed at different locations. Each donor antenna serves a specific spatial region, and the combined coverage from all donor antennas provides uniform power distribution throughout the indoor area, eliminating power imbalance while maintaining comprehensive coverage
Solution Approach 2:
Each donor antenna is optimized for its specific local region, with signal strength and quality tailored to that area. This local optimization ensures that users in different locations experience balanced power levels, as each donor antenna provides appropriate coverage for its designated spatial region rather than uniform omnidirectional coverage
3Productivity
If repeaters are spaced well-apart to reduce correlation and increase MIMO rank, then spectral efficiency is improved, but system complexity and installation cost increase
Solution Approach 1:
The repeater units are designed as universal, standardized modules that can be installed at multiple locations using the same hardware and configuration. This multi-functionality allows the system to achieve high MIMO rank through spatial distribution while avoiding the complexity of custom designs for each repeater location, as the same universal unit can be deployed across different sites
Solution Approach 2:
Multiple repeater units are combined into a coordinated system where each unit operates independently but contributes to the overall MIMO capacity. The repeaters are synchronized and coordinated to work together as a unified system, achieving high spectral efficiency through combined MIMO capacity while managing complexity through standardized modular architecture
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves excellent indoor coverage with high bit-rate and spectrally efficient communication, reducing power imbalances and increasing MIMO gains, while minimizing installation costs by using leaky cables to cover large areas uniformly.
Implementation Method 1
at least one leaky cable, provided inside said physical structure, for indoor MIMO communication
Implementation Method 2
signals from the base station are received by the pick-up antenna on the outside of the building, where the signal level is high, and then the signals are re-radiated inside the building by the donor antenna
Data Source
AI summary
A MIMO communications system for communicating with a UE located inside a physical structure. The communication system includes a node comprising two node antennas. The node is configured for LOS wireless communication with at least first and second repeaters. The first and second repeaters each have a) an antenna provided outside the physical structure for outdoor MIMO communication with the node and b) a leaky cable provided inside the physical structure for indoor MIMO communication with the UE.