Fronthaul Interface for Centralized Radio Access Network
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Solution Overview
Problem
Deploying centralized radio access networks (C-RANs) with special-purpose CPRI synchronous optical links is expensive and inconvenient, compared to using switched Ethernet networks for fronthaul implementation.
Innovation Solution
A system where physical layer processing for wireless interfaces is split between controllers and radio points, with scrambling of downlink data performed in both the controller and radio points, and specific signal processing tasks for LTE and 5G-NR wireless interfaces are allocated to either the controller or radio points, using a switched Ethernet network for communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CPRI synchronous optical links are deployed for fronthaul, then reliability and performance are improved, but cost and device complexity increase
Solution Approach 1:
The patent makes radio points multi-functional by enabling them to perform both RF transceiver functions and physical layer processing functions. This allows the system to use standard Ethernet infrastructure for fronthaul while maintaining the reliability previously requiring specialized CPRI links, as the radio points can locally execute scrambling, reference signal generation, and other Layer-1 functions
Solution Approach 2:
The patent segments the physical layer processing functions between controllers and radio points. Controllers handle higher-layer processing while radio points handle specific Layer-1 functions locally, allowing fronthaul to carry only necessary data (scrambled data, reference signals) rather than complete baseband signals, thus enabling use of lower-cost Ethernet infrastructure
2Productivity
If CPRI synchronous optical links are deployed for fronthaul, then performance is improved, but ease of manufacture and deployment worsen
Solution Approach 1:
Radio points are designed with multi-functionality to perform both traditional RF functions and physical layer processing functions locally. This eliminates the need for specialized CPRI optical links and allows deployment using standard Ethernet infrastructure, significantly improving ease of manufacture and deployment while maintaining service provision efficiency
Solution Approach 2:
The patent introduces an intermediary processing layer at the radio point that handles physical layer functions locally. This intermediary layer processes data before transmission over fronthaul, enabling the use of standard Ethernet as an intermediary transport medium rather than requiring dedicated optical links
3Device complexity
If physical layer processing is centralized in controllers, then device complexity at radio points is reduced, but fronthaul data volume and cost increase
Solution Approach 1:
The patent segments physical layer processing functions between controllers and radio points. Controllers perform functions like resource allocation and higher-layer processing, while radio points perform local functions including scrambling, reference signal generation, and modulation. This segmentation reduces fronthaul data volume by processing data closer to the air interface
Solution Approach 2:
The patent changes the functional dimension of radio points from simple RF transceivers to multi-functional units that perform physical layer processing. This dimensional change in functionality allows distributed processing that reduces fronthaul data requirements while maintaining manageable radio point complexity
Data Source
AI summary
One embodiment is directed to a system that is configured to communicate at least two different types of fronthaul data from a plurality of baseband units to a shared radio point using a single application-layer protocol that supports at least two types of elements. Each of the at least two types of elements is configured for a respective one of the at least two different types of fronthaul data. The system is configured so at least some of the elements communicated using the application-layer protocol include one or more sub-elements, where each sub-element comprises a type field, a length field, and a value portion.