IQ Data Segmentation for C-RAN Fronthaul Error Correction
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Solution Overview
Problem
In cellular telecommunications networks, the accuracy of In-Phase and Quadrature (IQ) data streams is compromised due to lossy compression techniques used in Centralised Radio Access Networks (C-RAN), leading to increased Error Vector Magnitude (EVM) and reduced data throughput, necessitating either increased bit width or more robust Modulation and Coding Schemes (MCS) to maintain compliance with EVM requirements.
Innovation Solution
A method is introduced where a first base station unit processes IQ data by preparing a first data package for transmission, determining an error value, and if it exceeds a threshold, a second data package is prepared with additional error-reducing IQ samples, which are transmitted over a secondary communications link to maintain EVM within acceptable limits without switching to higher bit width or more robust MCS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lossy compression techniques are used to reduce bit width of IQ data, then capacity utilisation of fronthaul link is reduced and data throughput increases, but accuracy of IQ data stream deteriorates and EVM increases
Solution Approach 1:
The IQ data transmission is segmented into two separate packages: a first data package containing compressed IQ data for high throughput, and a second data package containing additional compressed IQ data to correct errors and reduce EVM. This segmentation allows each package to be optimized for different purposes, resolving the contradiction between throughput and accuracy.
Solution Approach 2:
The second data package acts as an intermediary that mediates between the compressed first data package and the final reconstructed IQ data. By transmitting additional compressed IQ data in the second package, the system can reduce the EVM of the combined data without increasing the bit width of the original compressed data, thus maintaining throughput while improving accuracy.
2Measurement precision
If higher bit width is used to maintain EVM requirements, then accuracy is improved, but capacity utilisation of fronthaul link increases and data throughput decreases
Solution Approach 1:
Instead of transmitting full-precision IQ data (excessive action), the system transmits a first data package with reduced bit width (partial action) and supplements it with a second data package containing additional compressed IQ data. This partial action approach achieves EVM compliance without the overhead of full-precision transmission, maintaining throughput.
Solution Approach 2:
The system changes the parameter of compression ratio differently for the two data packages. The first data package uses a higher compression ratio (lower bit width) for efficiency, while the second data package uses a different compression ratio to provide error correction. This parameter change allows the system to achieve both throughput and EVM compliance.
3Reliability
If more robust Modulation and Coding Schemes are used to maintain EVM requirements, then reliability is improved, but transmission latency increases
Solution Approach 1:
The system performs preliminary compression on the IQ data before transmission, creating the first data package with reduced bit width. By pre-compressing the data and preparing the two-package structure in advance, the system avoids the need for more robust (but slower) modulation and coding schemes, thus maintaining low latency while achieving EVM compliance through the combination of both packages.
Data Source
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AI summary
This invention provides a method of operating a first base station unit to process In-Phase and Quadrature, IQ, data for transmission to a second base station unit, the first and second base station units both being part of a disaggregated base station in a cellular telecommunications network, the method comprising the steps of: preparing a first data package, based on IQ data, for transmission to the second base station unit; determining a first error value between the IQ data and the first data package; causing transmission of the first data package to the second base station unit; determining that the first error value exceeds a first error threshold; and, in response to the determination that the first error value exceeds the first error threshold: preparing a second data package, based on the IQ data, for transmission to the second base station unit, wherein a second error value between the IQ data and a combination of the first and second data packages is less than the first error value, and causing transmission of the second data package to the second base station unit. This invention further provides a method of operating a second base station unit to process a first and second data package processed by a first base station, the method comprising the step of combining the first and second data package.