Crest Factor Reduction Module Positioning in Distributed Antenna Systems
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Solution Overview
Problem
In distributed antenna systems (DAS), the implementation of crest factor reduction (CFR) modules at the front end of remote units increases complexity and cost, especially when multi-band signal processing is required, leading to significant challenges in managing signal degradation and RU complexity.
Innovation Solution
Positioning the CFR module optimally within the DAS topology, either in the hub unit or head-end unit, posterior to the mixing processing stage, allows for efficient digital mixing and signal processing, reducing signal degradation and RU complexity by minimizing the number of required CFR modules across the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the CFR module is implemented at the front end of each remote unit in a distributed antenna system, then signal quality is improved through local crest factor reduction, but device complexity and system cost increase significantly
Solution Approach 1:
The patent extracts the CFR module from the remote units and relocates it to the head-end unit. This centralization removes the complexity of implementing CFR at multiple distributed locations while maintaining the signal quality benefits. The head-end unit becomes the single point for crest factor reduction, eliminating the need for duplicate CFR functionality in each remote unit.
Solution Approach 2:
The patent merges the CFR functionality from multiple remote units into a single centralized CFR module at the head-end unit. By combining what was previously distributed across multiple locations into one location, the system reduces overall device complexity while maintaining the necessary signal processing capabilities.
2Adaptability or versatility
If multiple CFR modules are deployed across numerous remote units for multi-band signal processing, then signal processing capability is enhanced, but system cost and implementation complexity increase considerably
Solution Approach 1:
The centralized CFR module at the head-end unit is designed to handle multiple frequency bands and serve multiple remote units simultaneously. This single multi-functional module replaces what would otherwise require multiple separate CFR modules distributed across the system, reducing implementation complexity while maintaining multi-band processing capability.
Solution Approach 2:
The head-end unit acts as an intermediary that performs crest factor reduction on signals before they are distributed to multiple remote units. This centralized intermediary approach allows the system to achieve multi-band signal processing without deploying CFR functionality at each remote unit location.
3Reliability
If CFR is implemented at the front end of remote units, then local signal optimization is achieved, but the number of required CFR modules increases with the number of remote units
Solution Approach 1:
The patent extracts the CFR functionality from the remote units and consolidates it at the head-end unit. This extraction eliminates the need for multiple CFR modules distributed across the system, reducing the quantity of CFR modules from N (where N is the number of remote units) to just one centralized module.
Solution Approach 2:
The patent merges multiple separate CFR modules into a single centralized CFR module at the head-end unit. By combining the functionality that was previously distributed across multiple locations into one location, the system reduces the total number of CFR modules required while maintaining signal optimization capabilities.
Data Source
AI summary
A distributed antenna system includes a plurality of head-end devices for each receiving mobile communication signals from at least one corresponding base station, a hub communicatively coupled to the plurality of head-end devices, and a plurality of remote devices communicatively coupled to the hub, wherein the hub configured to distribute the mobile communication signals received from each of the plurality of head-end devices to the plurality of remote devices, wherein each of the plurality of remote devices is remotely disposed to transmit the distributed mobile communication signals to a terminal in service coverage, and wherein the hub includes a mixing processing stage configured to perform digital mixing processing on the mobile communication signals respectively received from the plurality of head-end devices, and a crest factor reduction (CFR) module disposed posterior to the mixing processing stage, with respect to a signal transmission direction.