RF Multiplexing for Add-on Remote Units in Optical Fiber DAS
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Solution Overview
Problem
Existing optical fiber-based distributed antenna systems (DAS) face challenges in supporting new or additional wireless communications services without requiring new optical fibers, leading to increased deployment costs and service disruptions.
Innovation Solution
The integration of radio frequency (RF) multiplexing allows for the addition of new remote units (RUs) to existing optical fiber-based DAS without deploying new optical fibers, by using existing optical fiber communications media to support additional wireless communications services through RF multiplexing and signal conversion at the head end equipment (HEE) and remote units (RUs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If new RUs are added to support additional wireless communications services, then the system capacity and service coverage are improved, but new optical fibers must be installed which increases deployment costs and causes service disruptions
Solution Approach 1:
The existing optical fiber infrastructure is made multi-functional by enabling it to carry both traditional optical communication signals and RF signals for new wireless services. The HEE and RU are configured to handle multiple signal types simultaneously, allowing the same physical medium to serve multiple purposes without requiring additional fibers.
Solution Approach 2:
RF multiplexing acts as an intermediary mechanism that allows additional wireless services to be transmitted over the existing optical fiber infrastructure. By converting optical signals to RF signals and vice versa, the system can accommodate new services without physical infrastructure changes.
2Adaptability or versatility
If traditional optical fiber infrastructure is used exclusively for optical communications, then signal transmission reliability is maintained, but the system cannot support additional wireless communications services without new fiber installations
Solution Approach 1:
The signal transmission is segmented into different domains: optical domain for traditional communications and RF domain for new wireless services. The HEE performs optical-to-RF conversion while RUs perform RF-to-optical conversion, allowing each domain to maintain its reliability characteristics while supporting diverse services.
Solution Approach 2:
The system changes the operational parameters of the existing infrastructure by introducing RF multiplexing capabilities. The optical fiber medium is utilized not only for optical signals but also for RF signal transmission through appropriate conversion at HEE and RU, expanding the parameter space without compromising existing performance.
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
This approach reduces service disruptions and deployment costs by enabling the support of additional wireless communications services within existing optical fiber-based DAS without the need for new fiber installations, enhancing the system's capacity to meet growing user demands.
Implementation Method 1
The HEE frontend interface is configured to multiplex the at least one existing downlink electrical RF communications signal and the at least one add-on downlink electrical RF communications signal to generate a downlink multiplexed RF signal
Implementation Method 2
The HEE frontend interface is configured to convert the downlink multiplexed RF signal into a downlink multiplexed optical signal
Implementation Method 3
The RU frontend interface is configured to convert the downlink multiplexed optical signal into a downlink multiplexed RF signal
Implementation Method 4
The RU frontend interface is configured to demultiplex the downlink multiplexed RF signal to generate the at least one existing downlink electrical RF communications signal and the at least one add-on downlink electrical RF communications signal
Implementation Method 5
provide the downlink multiplexed optical signal to the downlink optical fiber
Data Source
AI summary
Embodiments disclosed in the detailed description include supporting an add-on remote unit(s) (RU) in an optical fiber-based distributed antenna system (DAS) over existing optical fiber communications medium using radio frequency (RF) multiplexing. An existing DAS comprises at least one existing head end equipment (HEE) communicatively coupled to a plurality of existing RUs through an existing optical fiber communications medium. In aspects disclosed herein, an add-on RU is added to the existing DAS to support additional wireless communications. No new optical fibers are required to be deployed to support communications to the add-on RU in the existing DAS. Instead, the existing DAS is configured to support the add-on RU through the existing optical fiber communications medium using RF multiplexing. As a result, the add-on RU can be added to the existing optical fiber-based DAS without adding new optical fibers, thus leading to reduced service disruptions and deployment costs.