Backfire Distributed Antenna System with Delayed Transport
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Solution Overview
Problem
Traditional cellular network strategies face challenges in providing consistent indoor coverage due to high penetration losses, high power load, and limited cell isolation, which degrade data throughput and increase soft handover zones, especially in HSDPA systems.
Innovation Solution
A distributed antenna system (DAS) with a backfire configuration and delayed signal transmission between widely spaced antennas, utilizing MIMO techniques like Space Time Coding and Spatial Multiplexing, to improve signal isolation and consistency, thereby enhancing the geometry factor and overall network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microcells are deployed in high traffic urban areas to provide deep indoor coverage, then coverage and capacity are improved, but cell isolation between neighboring cells deteriorates
Solution Approach 1:
The patent segments the coverage area by deploying multiple microcells with widely spaced antennas (300-500 meters apart) rather than using a single large cell. This segmentation creates distinct cell boundaries and reduces overlap between neighboring cells, thereby improving cell isolation while maintaining deep indoor coverage in high traffic areas.
Solution Approach 2:
The patent introduces a spatial dimension solution by widely distributing antennas across the coverage area rather than concentrating them in one location. This dimensional spread of antenna positions creates better geometric separation between cells, reducing interference while providing comprehensive indoor coverage.
2Reliability
If microcells are deployed with typical inter-site distances of 300-500 meters, then deep indoor coverage is achieved, but soft handover zones increase
Solution Approach 1:
The patent applies local quality by optimizing the specific geometry and positioning of each microcell based on local coverage requirements. By carefully selecting antenna positions and orientations within the 300-500 meter inter-site distance range, the system achieves deep indoor coverage in specific areas while minimizing the creation of large soft handover zones between cells.
3Productivity
If HSDPA operates on the same channel in neighbor cells, then spectral efficiency is improved, but signal to interference ratio deteriorates
Solution Approach 1:
The patent converts the potential harm of same-channel operation into a benefit by using widely spaced antenna positions (300-500 meters) to create natural geometric isolation. This spatial separation transforms the interference problem into an opportunity to maintain spectral efficiency through frequency reuse while the physical distance and antenna geometry provide sufficient isolation to protect the signal-to-interference ratio.
4Device complexity
If multiple antennas are closely spaced in MIMO networks, then device complexity is reduced, but signal coverage consistency deteriorates
Solution Approach 1:
The patent segments the MIMO antenna system into widely spaced antenna positions (300-500 meters apart) rather than using closely spaced arrays. This segmentation maintains manageable device complexity at each antenna location while the widespread geometric distribution across the coverage area ensures consistent signal coverage by providing diverse propagation paths and reducing shadowing effects.
Data Source
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AI summary
A distributed antenna system (DAS) is provided, comprising a host unit and a plurality of remote placed to define a common coverage area. Each of the plurality of remote units is communicatively coupled to the host unit, points at least partially towards the common coverage area, and simulcasts data from the host unit.