Fronthaul Multiplexing of Compressed IQ Data to Cut Memory Delay

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Solution Overview

Problem

Fronthaul multiplexers face challenges in expanding serviceable area due to insufficient memory capacity and delays caused by decompression and recompression processes in combining uplink signals in fronthaul networks.

Innovation Solution

A fronthaul multiplexer that combines compressed IQ data without decompressing it, utilizing a packet reception unit, buffer unit, combining unit, and packet output unit to optimize memory use and reduce delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the fronthaul multiplexer stores packets for a predetermined time to combine packets from multiple RUs with different delay times, then the serviceable distance can be extended, but the memory capacity is insufficient and increasing capacity is difficult

Engineering Contradiction:
Improveserviceable distanceVSAvoidmemory capacity
Core Design Contradiction:
Length of stationary objectVSQuantity of substance

Solution Approach 1:

The patent changes the processing parameter from decompressing IQ data to directly processing compressed IQ data. This parameter change allows the system to reduce memory capacity requirements while maintaining the ability to handle packets from multiple RUs with different delay times, thus extending serviceable distance without increasing memory capacity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of the conventional approach of decompressing IQ data before combining, the patent inverts the process by combining compressed IQ data directly. This inversion eliminates the need for large memory capacity to store decompressed data, allowing the system to extend serviceable distance with limited memory resources.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If the fronthaul multiplexer decompresses and recompresses signals to combine uplink signals, then the signals can be properly combined, but delay in signal transmission occurs

Engineering Contradiction:
Improvesignal combination accuracyVSAvoidsignal transmission delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the unnecessary decompression and recompression steps from the signal processing chain. By directly combining compressed IQ data without these intermediate steps, the system maintains signal combination accuracy while eliminating the time delay associated with decompression and recompression operations.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent skips the decompression and recompression steps entirely, rushing through the combining process directly on compressed data. This skipping of intermediate processing steps eliminates the time delay while maintaining the reliability of signal combination through appropriate handling of compressed data formats.

Inventive Principle:
Principle #21Skipping (Rushing through)

Data Source

PatentEP4120664B1Fronthaul multiplexer
Publication Date: 2025.07.23 SOLID
  • EP4120664B1 patent drawingFigure 1(a)~1(b)
  • EP4120664B1 patent drawingFigure 2(a)~2(b)
  • EP4120664B1 patent drawingFigure 3

AI summary

A fronthaul multiplexer according to one aspect of the present invention combines uplink packets in a compressed state that is received from two or more radio units so that the uplink packets are accumulated and combined immediately when received or the uplink packets are recompressed using a compressing method with high compression efficiency when stored in a memory in order to reduce a use amount of memory.