Radio Communication System Dynamic Function Sharing

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Solution Overview

Problem

Current radio communication systems, particularly in LTE and 5G, face challenges with high bandwidth requirements for the front haul (FH) due to centralized baseband processing, leading to increased costs and inefficiencies, especially with 2x2 MIMO and anticipated peak rates in 5G, which exceed the capabilities of the current CPRI standard.

Innovation Solution

A radio communication system that dynamically switches function sharing between the Baseband Unit (BBU) and Remote Antenna Unit (RAU) based on predetermined reference values, such as SINR, CRC success rate, or processing load, to optimize signal processing distribution and reduce the transmission load on the FH.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If centralized baseband processing is implemented in BBU, then control and management of multiple cells is improved, but the bandwidth required for front haul connection increases significantly

Engineering Contradiction:
Improvecontrol capabilityVSAvoidbandwidth
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent segments the baseband processing functions by introducing an intermediate processing unit between the BBU and RAU. This intermediate unit handles specific processing tasks (such as FFT, IFFT, or channel decoding) locally, dividing the overall processing load between centralized control (BBU) and distributed execution (intermediate unit + RAU), thereby reducing the bandwidth required on the front haul connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimensional layer in the processing architecture by adding the intermediate processing unit. This creates a three-tier structure (BBU - intermediate processing unit - RAU) that adds processing capability in a new dimension, allowing complex functions to be distributed across multiple layers rather than concentrating all processing in a single centralized unit.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the number of antennas is increased to support MIMO, then communication capacity is improved, but the CPRI bandwidth requirement increases proportionally

Engineering Contradiction:
Improvecommunication capacityVSAvoidCPRI bandwidth
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent segments the MIMO processing functions by placing antenna-specific processing (such as FFT, channel estimation, or equalization) in the intermediate processing unit or RAU, rather than requiring all MIMO processing to occur in the BBU. This segmentation allows the system to support multiple antennas and MIMO configurations while reducing the amount of data that must be transmitted over the CPRI connection.

Inventive Principle:
Principle #1Segmentation

3Productivity

If 5G peak rate requirements are implemented, then data transmission capability is improved, but the CPRI standard cannot support the required bandwidth

Engineering Contradiction:
Improvepeak rateVSAvoidstandard compatibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent segments the high-rate processing functions by introducing an intermediate processing unit that performs computationally intensive tasks locally. This allows the system to achieve 5G peak rates by distributing processing across multiple units rather than relying solely on the CPRI connection, thereby maintaining compatibility with existing CPRI standards while achieving future-proof performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent addresses the bandwidth limitation by adding a new processing dimension through the intermediate unit, transforming the system from a two-point connection (BBU-RAU) to a multi-point architecture. This dimensional change enables the system to achieve higher peak rates by utilizing local processing resources at the intermediate unit, bypassing the CPRI bandwidth constraint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Quantity of substance

If more signal processing functions are implemented in RAU, then front haul transmission load is reduced, but device complexity at RAU increases

Engineering Contradiction:
Improvetransmission loadVSAvoidprocessing complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent segments the processing functions by introducing an intermediate processing unit with specific, well-defined functions. Rather than implementing all processing functions in the RAU, the system divides functions across three units (BBU, intermediate processing unit, RAU), with each unit having optimized complexity appropriate to its role. This segmentation reduces both the transmission load and the complexity burden on any single device.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3425951B1Radio communication system and base station
Publication Date: 2022.06.08 NTT DOCOMO INC
  • EP3425951B1 patent drawingFigure 1
  • EP3425951B1 patent drawingFigure 2
  • EP3425951B1 patent drawingFigure 3

AI summary

There is provided a radio communication system provided with a first base station, a second base station that communicates with the first base station, and user equipment that communicates with the first base station, the radio communication system including a determiner that determines, based on a predetermined reference value, sharing between signal processing that is to be performed by the first base station and signal processing that is to be performed by the second base station; a first signal processor for the first base station to perform the signal processing in accordance with the sharing determined by the determiner; and a second signal processor for the second base station to perform the signal processing in accordance with the sharing determined by the determiner.