O-RAN RIC Antenna Coordination for Cell-Free Massive MIMO Interference
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Solution Overview
Problem
In cell-free massive MIMO systems, communication efficiency is compromised due to interference between terminal devices connected to different processing devices, as existing technologies do not account for the influence of signals received by antennas not directly involved in demodulation and decoding.
Innovation Solution
A control device and processing device configuration that utilizes a RAN Intelligent Controller (RIC) to identify and manage antennas for signal reception and transmission path estimation, minimizing interference by notifying O-DUs to perform specific processing tasks and allocate pilot symbols effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple processing devices are used to control different portions of antennas in a cell-free massive MIMO system, then the system can handle enormous numbers of antennas and terminal devices, but communication interference occurs between terminal devices connected to different processing devices
Solution Approach 1:
The system segments the large-scale MIMO system into multiple processing devices (O-DUs), each controlling a specific portion of antennas. This segmentation enables the system to handle enormous numbers of antennas and terminal devices by distributing the control load across multiple devices, thereby improving system capacity while managing complexity through modular architecture
Solution Approach 2:
A control device functioning as RAN Intelligent Controller (RIC) is introduced as an intermediary between terminal devices and multiple processing devices. The RIC identifies which antennas will receive signals with predetermined power and notifies the appropriate O-DU to perform transmission path estimation, thereby coordinating resource allocation across processing devices and reducing communication interference between terminal devices
2Reliability
If all antennas receive and process signals from all terminal devices, then complete signal processing is achieved, but communication efficiency deteriorates due to interference with other terminal devices
Solution Approach 1:
The patent applies local quality by having different processing devices perform different functions based on their local characteristics and assigned roles. The control device determines which specific antennas (local elements) should receive and process signals from each terminal device, rather than having all antennas process all signals uniformly. This selective local processing reduces interference and improves communication efficiency while maintaining necessary signal processing completeness
3Measurement precision
If transmission path estimation is performed for all antennas, then accurate channel information is obtained, but system complexity and processing overhead increase
Solution Approach 1:
The control device implements partial action by determining only the specific antennas that need to perform transmission path estimation for each terminal device, rather than requiring all antennas to perform estimation. The RIC identifies antennas expected to receive signals with predetermined power and notifies only those O-DUs to perform estimation, thereby obtaining sufficient channel information while reducing system complexity and processing overhead
Data Source
AI summary
A control device that functions as a RIC in an O-RAN identifies a plurality of antennas that are expected to receive, with at least a predetermined power, a signal from each of a plurality of terminal devices, and notifies an O-DU that is connected to first antennas included in the plurality of antennas for a first terminal device and executes demodulation and decoding processing for the first terminal device, and is connected to second antennas included in the plurality of antennas for a second terminal device and does not execute demodulation and decoding processing for the second terminal device, of information indicating the first antennas and information indicating a third antenna among the second antennas that is a target of transmission path estimation performed based on pilot symbols received from the second terminal device.