Bitmap Compression of Fronthaul User Data Between LLS-CU and RU

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in data transmission between lower-layer split central units and radio units due to high bit rates on the fronthaul interface, limiting the pooling of shared links.

Innovation Solution

Implementing a method to compress user data using bitmap representations, allowing for efficient transmission and decompression at the radio unit, thereby reducing the bit rate on the fronthaul interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If user data is transmitted without compression between LLS-CU and RU, then data integrity is maintained, but bit rate on the fronthaul interface increases

Engineering Contradiction:

Improvedata integrityVSAvoidbit rate

Core Design Contradiction:

Loss of informationVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by transforming the data representation format from full-precision complex numbers to compressed bitmap representations. This changes the parameter of data encoding from standard floating-point or fixed-point format to a compact binary map format, achieving compression while maintaining recoverability of original data through inverse transformation operations at the receiving end

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses copying by creating simplified bitmap representations that replicate the essential information of the original user data. Instead of transmitting the complete high-precision data, a compressed copy in bitmap form is transmitted, which can be accurately reconstructed at the RU side through decompression algorithms

Inventive Principle:

Principle #26Copying

2Quantity of substance

If bitmap compression is applied to user data, then bit rate on fronthaul interface is reduced, but processing complexity increases

Engineering Contradiction:

Improvebit rateVSAvoidprocessing complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the user data into discrete resource element groups that can be independently represented by bitmap segments. Each bitmap corresponds to specific resource elements, allowing selective compression and processing of data portions rather than treating the entire data stream as a single unit, thereby managing complexity through modular processing

Inventive Principle:

Principle #1Segmentation

3Quantity of substance

If bitmap representation is used for data compression, then bandwidth requirements are reduced, but transmission time increases due to compression and decompression operations

Engineering Contradiction:

Improvebandwidth requirementsVSAvoidtransmission time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The patent applies partial action by selectively applying bitmap compression only to portions of user data that benefit from compression, rather than uniformly compressing all data. The system identifies suitable candidates for compression and applies the bitmap representation selectively, avoiding the overhead of compression operations on data that would not benefit, thereby optimizing the trade-off between bandwidth savings and processing time

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20260025244A1Compressing user data transmitted between a lower layer split central unit and a radio unit using bitmap representations

Publication Date: 2026.01.22 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method for transmitting user data from a lower-layer split central unit (LLS-CU) to a radio unit (RU) in a network node of a wireless communication system for transmission by the RU over a wireless interface includes mapping reference symbols to be transmitted by the RU to resource elements to provide mapped data. The mapped data including the references symbols is compressed using a bitmap representation of the mapped data to obtain compressed data. The compressed data is transmitted from the LLS-CU to the RU.