O-RAN DU-RU Advanced Receivers for Uplink Interference
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Solution Overview
Problem
Existing open radio access network (O-RAN) technologies face challenges in managing interference and optimizing signal processing between the radio unit (RU) and distributed unit (DU), particularly in scenarios involving massive MIMO, where intra-cell and inter-cell interference are significant, impacting spectral efficiency.
Innovation Solution
Implementing advanced receivers with interference cancellation functionalities in both the DU and RU, and optimizing the O-RAN fronthaul interface to support split 7.2x, 7.3, enabling efficient beamforming and equalization across the RU and DU, with mechanisms like SIC and PIC to mitigate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If advanced receivers with interference cancellation functionalities are implemented in both DU and RU, then uplink performance and spectral efficiency are improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the interference cancellation functionality between the RU and DU components. The RU performs local interference cancellation for immediate signal processing, while the DU handles higher-layer interference management and coordination. This distributed segmentation allows each component to manage complexity locally while contributing to overall system spectral efficiency improvement.
Solution Approach 2:
The fronthaul interface acts as an intermediary between the RU and DU, enabling coordinated interference cancellation. The interface facilitates information exchange about interference conditions, signal characteristics, and cancellation progress, allowing both components to work together seamlessly. This intermediary mechanism enables complex interference management without requiring full centralized control.
2Reliability
If interference cancellation mechanisms like SIC and PIC are implemented, then uplink performance is enhanced, but processing time and computational requirements increase
Solution Approach 1:
The system performs preliminary channel estimation and interference characterization at the RU before executing full interference cancellation. By preparing interference profiles and signal statistics in advance, the actual cancellation process requires less computational time. The DU also performs preliminary resource allocation and power control to optimize subsequent cancellation operations.
Solution Approach 2:
The patent implements partial interference cancellation in the RU for time-critical signal processing, followed by complementary cancellation at the DU. This partial action approach handles the most time-sensitive interference removal locally, while the DU completes the cancellation process with less computationally intensive operations, balancing speed and completeness.
3Productivity
If the O-RAN fronthaul interface is optimized for split 7.2x and 7.3, then beamforming and equalization efficiency are improved, but interface complexity and configuration requirements increase
Solution Approach 1:
The patent optimizes the fronthaul interface by dynamically adjusting transmission parameters such as data granularity, sampling rates, and error correction codes based on the specific split configuration (7.2x or 7.3). The system automatically adapts these parameters to match the functional division between RU and DU, improving beamforming efficiency without requiring manual interface reconfiguration for different split types.
Solution Approach 2:
The fronthaul interface is designed with multi-functionality to support multiple functional splits (7.2x and 7.3) as well as various beamforming configurations. The interface includes universal protocols and data structures that can accommodate different splitting scenarios, allowing the same physical interface to serve multiple purposes without requiring separate specialized interfaces for each configuration type.
Data Source
AI summary
An apparatus and method for supporting advanced receiver in an open radio access network. A distributed unit (DU) and a radio unit (RU) in a radio access network include an advanced receiver for supporting interference cancellation in the uplink transmissions. The DU provides to the RU demodulation reference signal (DMRS) configuration information and information regarding resource partition of scheduled resources for uplink transmissions from user equipments (UEs) in a slot. The RU receives uplink transmissions from UEs and sends equalized modulation symbols of at least one resource partition to the DU. The DU decodes the equalized modulation symbols, reconstructs modulation symbols for at least one resource partition based on the decoded modulation symbols, and sends the reconstructed modulation symbols to the RU. The RU performs interference cancellation on the modulation symbols of the uplink transmissions based on the reconstructed modulation symbols and sends interference-cancelled equalized modulation symbols to the DU.