Split RAN Uplink Beamforming and RU Equalization Control
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Solution Overview
Problem
In split RAN deployments, the beamforming design at the RU may be outdated due to changes in the channel between the user and the RU, leading to suboptimal communication performance, and equalization at the DU introduces constraints on air interface performance, RU complexity, fronthaul throughput, interoperability, and ecosystem fragmentation.
Innovation Solution
Enabling the RU to generate beams based on the latest uplink signal by adding DMRS processing and allowing equalization at the RU, with control options determined by the DU, and utilizing AI/ML for mode selection to optimize beamforming and equalization responsibilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If equalization is performed at the DU in split RAN deployments, then uplink signal processing can be centralized, but this introduces constraints on air interface performance, RU complexity, fronthaul throughput, interoperability, and ecosystem fragmentation
Solution Approach 1:
The patent segments the equalization function from the DU and relocates it to the RU. This allows the RU to perform equalization locally on uplink signals before transmission over the fronthaul interface, thereby improving air interface performance and reducing fronthaul throughput requirements without centralizing all processing at the DU. The segmentation resolves the contradiction by distributing processing functions appropriately.
Solution Approach 2:
The patent introduces a new dimension of flexibility by enabling equalization at the RU through additional processing capabilities. This dimensional change allows the system to adapt between centralized (DU-based) and distributed (RU-based) equalization modes, resolving the contradiction by providing multiple operational dimensions rather than a fixed architecture.
2Ease of manufacture
If beamforming design at the RU is based on outdated channel information, then system implementation is simpler, but communication performance becomes suboptimal
Solution Approach 1:
The patent implements feedback mechanisms where the RU receives channel state information from the DU and uses this feedback to update its beamforming design. The RU can obtain fresh channel information through uplink signal processing and DMRS, allowing it to adapt beamforming weights dynamically rather than relying on outdated designs, thus resolving the contradiction between simplicity and performance.
Solution Approach 2:
The patent transforms the static beamforming design into a dynamic process where the RU can adapt beamforming parameters based on current channel conditions. By enabling the RU to perform equalization and use latest uplink signals for beamforming calculations, the system achieves dynamic adaptation without overly complicating the implementation.
Data Source
AI summary
Aspects of the subject disclosure may include, for example, a method that includes receiving, by a processing system, an uplink signal at a radio unit (RU) communicating over a fronthaul interface with a distributed unit (DU) of a communication network; receiving a demodulated reference signal (DMRS) configuration at the RU; performing a beamforming procedure at the RU for one or more beams generated at the RU; and determining, in accordance with an option selected by the DU, whether to perform an equalization procedure for the uplink signal at the RU resulting in equalized user data. In accordance with the equalization procedure being performed at the RU, equalization for the uplink signal is not performed at the DU. Other embodiments are disclosed.