Bidirectional Leaky Cable MIMO Coverage Design
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Solution Overview
Problem
Existing indoor wireless communication systems using leaky cables face challenges in providing cost-effective and efficient high bit-rate, spectrally efficient coverage due to the high cost and complexity of installation, as well as non-uniform signal-to-noise ratio distribution along the cables, which is exacerbated in multiple-input multiple-output (MIMO) applications.
Innovation Solution
A wireless communication system and method utilizing a node with at least two antenna ports and at least one leaky cable, where both ends of the cable are connected to the node's antenna ports, either directly or via signal dividers, to enable wireless MIMO communication, thereby reducing installation costs and achieving uniform capacity distribution by halving the cable length and using signal dividers for even power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple leaky cables are installed in parallel for MIMO communications, then communication capacity and bit rate are improved, but installation cost and complexity increase significantly
Solution Approach 1:
The patent combines multiple cable functions into a single leaky cable by implementing bidirectional communication capabilities. The cable supports both forward and reverse signal transmission through the same physical medium, eliminating the need for separate parallel cables for different communication streams while maintaining MIMO capacity requirements.
Solution Approach 2:
The leaky cable is designed to perform multiple functions simultaneously: it serves as both transmit and receive medium, supports multiple communication streams through bidirectional operation, and provides both coverage and capacity enhancement. This multi-functionality replaces what would traditionally require multiple separate cable installations.
2Area of stationary object
If long leaky cables are used to cover large areas, then coverage area is improved, but signal-to-noise ratio deteriorates at distant locations
Solution Approach 1:
Instead of transmitting signals in only one direction from the base station, the system inverts the approach by enabling bidirectional transmission where signals can propagate from both ends of the cable toward the center. This inversion of the unidirectional transmission model allows distant users to receive stronger signals from the direction closer to them, significantly improving SNR throughout the coverage area.
3Ease of manufacture
If traditional unidirectional leaky cable installation is used, then installation simplicity is maintained, but capacity distribution becomes highly non-uniform along the cable
Solution Approach 1:
The patent applies bidirectional transmission where signals propagate from both ends of the cable toward the center, inverting the traditional unidirectional approach. This creates a more uniform capacity distribution because users at any position along the cable are equidistant from one of the two signal sources, eliminating the severe capacity skew that occurs in unidirectional systems where capacity degrades linearly from the transmitting end.
4Reliability
If signal amplifiers are installed along the leaky cable to improve SNR, then signal-to-noise ratio is improved, but installation cost and power requirements increase
Solution Approach 1:
The bidirectional leaky cable system is self-service in that it automatically improves SNR through its inherent bidirectional propagation characteristic without requiring external amplification devices. The system uses the cable's own structure and dual-ended transmission capability to provide signal reinforcement, eliminating the need for separate amplifier installations and their associated power and cost requirements.
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 solution reduces installation costs and provides more uniform capacity distribution along the cable length, maintaining performance and allowing for easy upgrade of single-input systems to MIMO, with simulations showing improved capacity distribution especially at higher signal-to-noise ratios.
Implementation Method 1
at least one leaky cable having two ends and being provided at least partially inside said physical structure, each end of said at least one leaky cable being connected to one of said antenna ports of said node, wherein said at least one leaky cable is adapted for wireless communication over a radio channel with said user equipment
Data Source
AI summary
The invention relates to a wireless communications system for communicating with user equipment located inside a physical structure. The system comprise a node having at least two antenna ports and being adapted for wireless communication with the user equipment, and at least one leaky cable having two ends wherein each end of the at least one leaky cable is connected to one of the antenna ports of the node. The at least one leaky cable is provided at least partially inside the physical structure and being adapted for wireless communication over a radio channel with the user equipment.