C-RAN Fronthaul Quantization Control for Fiber Link Bottlenecks
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Solution Overview
Problem
Conventional Centralized Radio Access Network (CRAN) systems face flexibility and scalability issues due to software and hardware modifications required for algorithm changes, and existing solutions do not adequately reduce data rates on fiber links to support a large number of remote units, leading to bottlenecks and increased data rates with modern radio access technologies.
Innovation Solution
A method and system that dynamically adjust the quantization bit number based on network information to optimize data transmission over fronthaul links, allowing for variable quantization of data transmitted between central and remote units, thereby distributing data load capacity and reducing the overall throughput on fiber links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CRAN systems transmit composite base-band signals over fiber links according to OBSAI or CPRI standards, then signal transmission is achieved, but the available transmission capacity on fiber links rapidly becomes a bottleneck as the number of remote units increases
Solution Approach 1:
The patent segments the composite base-band signal into individual user signals, allowing selective transmission of only those signals corresponding to active users. This segmentation reduces the overall data rate on fiber links while maintaining reliable signal transmission for active users, directly addressing the capacity bottleneck problem.
Solution Approach 2:
The patent extracts and transmits only the necessary user signals from the composite base-band signal over the fiber link, rather than transmitting the entire composite signal. This extraction approach reduces the quantity of data transmitted while ensuring reliable delivery of essential signals, resolving the contradiction between transmission reliability and available capacity.
2Reliability
If signal processing algorithms such as adaptive beamforming and network coordination are implemented at central units, then system performance is improved, but software and hardware modifications are required for algorithm changes, reducing flexibility
Solution Approach 1:
The patent extracts the signal processing functionality from the central unit and relocates it to the remote units. Each remote unit independently processes its assigned user signals using algorithms such as adaptive beamforming and network coordination. This extraction enables flexible algorithm updates at remote units without requiring modifications to the central unit's software or hardware, resolving the contradiction between system performance and algorithm flexibility.
3Area of stationary object
If the number of remote units connected to a central unit increases, then network coverage is expanded, but the available transmission capacity on fiber links becomes saturated
Solution Approach 1:
The patent segments the total signal transmission into individual user signal transmissions. By transmitting only the signals corresponding to active users at each remote unit rather than all possible signals, the data rate requirement per fiber link is significantly reduced. This enables the network to support a larger number of remote units and expand coverage area without saturating the fiber link capacity.
Solution Approach 2:
The patent transitions from transmitting signals in the time domain to transmitting signals in the frequency domain. This dimensional change allows for more efficient spectral utilization and reduced data rates, enabling expanded network coverage with existing fiber link capacity.
4Productivity
If data rates on fiber links are increased to support modern radio access technologies such as MIMO and carrier aggregation, then system capacity is improved, but the bottleneck effect on fiber links is exacerbated
Solution Approach 1:
The patent segments the high-rate composite signal into individual user signals, transmitting only the necessary subset over the fiber link. This segmentation maintains high system capacity for active users while reducing the overall fiber link load, preventing bottleneck effects even when supporting modern radio access technologies like MIMO and carrier aggregation.
Solution Approach 2:
The patent transmits only the partial set of signals corresponding to active users rather than the full composite signal. This partial action approach maintains sufficient system capacity for current users while avoiding the excessive fiber link load that would result from transmitting all possible signals, thus preventing bottleneck effects.
Data Source
AI summary
A method is proposed of arranging, in a mobile communication network, transmission of data between user equipment and at least one base station including a central unit and at least one remote unit associated therewith. The method includes at a transmitting side including the remote unit or the central unit, quantizing the data according to a quantization bit number, and transmitting, over a fronthaul link between the transmitting side and a receiving side including the central unit or the remote unit, respectively, the quantized data to the receiving side. The method further includes, at the central unit: determining the quantization bit number, wherein the determining including varying in time the quantization bit number according to network information available at the central unit, and communicating to the at least one remote unit the determined quantization bit number.