CBRS Interference Measurement With Coordinated CBSD Blanking
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Solution Overview
Problem
Existing CBRS systems face challenges in coordinating interference among General Authorized Access (GAA) users and external interfering sources, lacking effective methods to measure and mitigate interference in 4G LTE and 5G NR wireless networks.
Innovation Solution
Implement a Radio Measurement Controller (RMC) and Interference Processor at the O-DU, utilizing Coordinated Blank OFDM Symbols (CBOS) to selectively mute neighboring CBSDs, enabling interference measurement and localization of external interferers through triangulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coordinated blanking is implemented to measure interference from external sources, then interference measurement precision is improved, but network service continuity deteriorates due to temporary service interruption during measurement
Solution Approach 1:
The system implements periodic coordinated blanking measurements at predetermined intervals rather than continuous blanking. The RMC schedules measurement occasions where neighboring CBSDs are temporarily muted for short durations, allowing the target CBSD to measure interference while maintaining service during non-measurement periods. This periodic approach balances measurement needs with service continuity.
Solution Approach 2:
The system performs preliminary coordination among CBSDs before conducting interference measurements. The RMC exchanges measurement configuration information with neighboring CBSDs in advance, allowing them to prepare for coordinated blanking. This preliminary coordination ensures that measurements are conducted smoothly with minimal service disruption and enables the system to schedule measurements during periods of lower traffic demand.
2Measurement precision
If coordinated blanking is used to locate external interferers, then localization accuracy is improved, but system complexity increases due to multi-CBSD coordination requirements
Solution Approach 1:
The RMC serves as an intermediary that centralizes the coordination of coordinated blanking measurements. Instead of requiring direct peer-to-peer coordination between multiple CBSDs, the RMC receives measurement requests, determines appropriate measurement configurations, and distributes coordinated blanking schedules to participating CBSDs. This intermediary approach simplifies the system architecture by consolidating coordination logic in a single entity.
Solution Approach 2:
The system segments the interference measurement function into distinct components: the RMC handles coordination and decision-making, while individual CBSDs execute local transmission muting and measurement actions. This segmentation allows each component to focus on specific tasks, reducing overall system complexity while maintaining the capability for multi-CBSD coordinated measurements for interferer localization.
3Measurement precision
If neighboring CBSDs are muted during measurement, then interference measurement accuracy is improved, but resource utilization deteriorates due to wasted transmission opportunities
Solution Approach 1:
The system applies partial blanking where only specific resource blocks or time-frequency resources are muted during measurement occasions, rather than muting all transmissions from neighboring CBSDs. This partial action approach allows the system to maintain transmission on resources that do not interfere with the measurement, thereby improving resource utilization while still achieving accurate interference measurement on the targeted resources.
Solution Approach 2:
Coordinated blanking measurements are conducted periodically at predetermined intervals rather than continuously. During non-measurement periods, neighboring CBSDs resume normal transmissions, fully utilizing available resources. This periodic approach ensures that measurement activities occupy only a small fraction of total system time, minimizing the impact on overall resource utilization while maintaining measurement accuracy.
Data Source
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AI summary
A method for measuring radio interference at a center Citizens Broadband Radio Service (CBRS) device (CBSD) of a selected network operator operating one of a 4G Long Term Evolution (LTE) network or a 5G New Radio (NR) network, includes: instructing, by a radio measurement controller, the center CBSD to perform measurement of radio interference caused by an interfering radio source; instructing, by the radio measurement controller, at least one neighboring CBSD to stop radio service for at least one coordinated blank orthogonal frequency-division multiplexing symbol (CBOS), wherein the at least one CBOS is defined by a selected frequency range and a selected blanking time in one of a subframe or a slot in one of a time division duplex (TDD) downlink (DL) configuration or a TDD uplink (UL) configuration; and processing, by an interference processor associated with the center CBSD, the measured radio interference.