RF to LF Conversion Unit for Copper Cable Transport
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Solution Overview
Problem
The existing radio over copper (RoC) systems face significant interference issues due to far-end crosstalk (FEXT) in twisted-pair cables, limiting the effective transport of wide radio spectra and high-data-rate services in radio networks, especially when multiple antennas are deployed.
Innovation Solution
A conversion unit that downconverts RF signals to LF bands for transmission over copper cables, allowing flexible allocation of RF channels across multiple cables and antennas, thereby mitigating FEXT interference through space-frequency to space-frequency mapping and utilizing phantom-mode communication to increase bandwidth capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RF signals are transported directly over copper cables in RoC systems, then the existing copper infrastructure can be reused and power can be delivered over the same cables, but far-end crosstalk (FEXT) interference significantly limits the effective transport of wide radio spectra and high-data-rate services
Solution Approach 1:
The patent transforms the single-frequency RF signal transport into multi-dimensional transport by mapping different RF channels to different spatial dimensions (multiple cable pairs) and frequency dimensions (LF bands). This space-frequency mapping allows simultaneous transport of multiple channels while separating their spectral content to reduce FEXT interference between channels.
Solution Approach 2:
The patent segments the wide RF spectrum into multiple narrower LF bands, each transported over separate cable pairs or groups. This segmentation reduces the bandwidth occupied by each signal, thereby reducing the FEXT interference that scales with bandwidth, while still enabling aggregate high-data-rate services through parallel transmission.
2Productivity
If multiple antennas are deployed at RUs to increase RAN capacity, then throughput per square-km increases, but the data-rate over copper cables scales proportionally and reaches hundreds of Gbps which is difficult to transport
Solution Approach 1:
The patent replaces the direct RF-to-LF conversion approach with an intermediate frequency translation stage. RF signals are first downconverted to LF bands before cable transmission, which reduces the bandwidth expansion effect and allows higher antenna counts to be supported without proportionally increasing the cable data-rate requirement.
Solution Approach 2:
The patent combines multiple RF channels from multiple antennas into a consolidated LF band transmission over copper cables. By merging the spectral content of multiple channels into lower frequency bands that can be efficiently transported over copper, the system supports high antenna counts while maintaining manageable cable data-rates.
3Measurement precision
If RF signals are digitized and transported as digital IQ streaming, then synchronization and processing are improved, but bandwidth expansion occurs that can be as high as x30
Solution Approach 1:
The patent implements dynamic frequency translation where RF signals are continuously downconverted to LF bands adapted to the copper cable characteristics. This dynamic approach allows the system to maintain signal integrity and synchronization while adapting the bandwidth usage to the actual cable capacity, avoiding the fixed x30 bandwidth expansion of digitalization.
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 enables robust and efficient transport of RF signals over copper cables, reducing FEXT interference and enhancing network resource utilization, supporting high-data-rate services and multiple antenna deployments without significant bandwidth expansion.
Implementation Method 1
The conversion unit is configured for downconverting a RF radio signal received at the RF interface in a first RF band from the first RF band to a first LF band
Implementation Method 2
for up-converting an electric signal received via one of the copper cables in a second LF band from the second LF band to a second RF band
Data Source
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AI summary
The present invention relates to a conversion unit (41) configured for downconverting a RF radio signal from a first RF band to a first LF band, and up-converting an electric signal from a second LF band to a second RF band; the LF and RF bands have same bandwidth, while RF bands are centered on central frequencies being higher than the LF central frequencies of the LF bands. The conversion unit (41) is adapted to select the copper cable link (5) and the first LF band on which transmitting the downconverted RF signal according to a predetermined criteria between a plurality of RF frequency bands and said plurality of copper cable links, and to select the RF connection and the second RF band on which transmitting the upconverted LF signal according to a predetermined criteria between said plurality of RF connections and a plurality of RF bands.