MIMO Fronthaul Compression Using Radio Frame Structure Maps
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Solution Overview
Problem
Massive MIMO systems face high communication requirements over fronthaul links due to high bandwidths and large numbers of antennas, with existing compression algorithms designed for single antenna devices failing to exploit the correlation in multi-antenna signals, leading to inefficiencies in data transmission.
Innovation Solution
A multi-antenna apparatus with compressors and decompressors that exploit the radio frame structure to compress and decompress frequency-domain digital signals, specifically designed for each data channel type, reducing the communication requirements between RRUs and BBUs while maintaining low distortion or error vector magnitude (EVM).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If standard CPRI compression algorithms are used for MIMO systems, then compression can be applied in a per antenna basis, but these algorithms fail to exploit the correlation in multi-antenna signals, resulting in insufficient compression gains
Solution Approach 1:
The patent segments the frequency-domain digital signal into multiple frequency-domain digital sub-signals, each allocated to a respective resource block. This segmentation enables independent processing of each sub-signal while maintaining the ability to exploit correlations across antennas through the radio frame structure map, thereby achieving better compression gains without excessive complexity.
Solution Approach 2:
The patent applies different compression approaches to different data channel types (PDSCH, PDCCH, PBCH, etc.) by using a radio frame structure map to identify and process each sub-signal according to its specific channel type. This local quality approach allows optimization for each channel's characteristics while maintaining overall system efficiency.
2Productivity
If high bandwidths and large numbers of antennas are used in M-MIMO systems, then spectral efficiency is increased, but the throughput requirements of fronthaul links become prohibitive
Solution Approach 1:
The patent transforms the compression problem from the time domain to the frequency domain by working with frequency-domain digital sub-signals allocated to resource blocks. This dimensionality change enables exploitation of correlations across multiple antennas and frequency resources simultaneously, achieving superior compression ratios that reduce fronthaul throughput requirements while maintaining spectral efficiency.
Solution Approach 2:
The patent changes the processing parameters by applying compression specifically tailored to different data channel types (PDSCH, PDCCH, PBCH, etc.) identified through the radio frame structure map. This parameter change allows optimization of compression for each channel type's statistical characteristics, maximizing data reduction while maintaining signal quality.
3Productivity
If compression is applied to reduce fronthaul throughput, then data transmission efficiency is improved, but signal distortion or error vector magnitude may increase
Solution Approach 1:
The patent employs feedback mechanisms where the radio frame structure map and channel type information are used to guide the compression and decompression processes. This feedback ensures that the decompression at the remote radio unit accurately reconstructs the original signal by maintaining consistency with the compression parameters derived from the known frame structure, thereby minimizing distortion and EVM.
Solution Approach 2:
The patent performs preliminary organization of the frequency-domain digital signal into resource blocks with associated channel type classifications before compression. This preliminary action, guided by the radio frame structure map, ensures that the compression process is prepared with all necessary information to maintain signal integrity during reconstruction, preventing excessive distortion.
Data Source
AI summary
A multi-antenna apparatus of a multi-input multi-output (MIMO) communication system for compressing and decompressing a frequency domain digital signal are provided, wherein a data channel type of each frequency-domain digital sub-signal of the frequency-domain digital signal is determined by a radio frame structure map (π). The multi-antenna apparatus includes a respective compressor and a respective decompressor associated to each data channel type, and is configured, for each frequency-domain digital sub-signal of the frequency-domain digital signal, to compress, at a first module, the frequency-domain digital sub-signal using the compressor associated to the data channel type of the frequency-domain digital sub-signal, and, for each compressed frequency-domain digital sub-signal, to decompress, at a second module communicating with the first module via an FH link, the compressed frequency-domain digital sub-signal using the decompressor associated to the data channel type of compressed frequency-domain digital sub-signal.