Dynamic Spectrum Sharing Interference Estimation Across LTE and NR
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Solution Overview
Problem
In wireless communications systems with dynamic spectrum sharing (DSS), UEs face challenges in accurately accounting for interference from neighboring base stations operating with different radio access technologies (RATs, such as LTE and NR), leading to unequal downlink throughput due to CRS interference cancellation issues and inability to update noise estimations.
Innovation Solution
User equipment (UE) identifies the transmission status of neighboring base stations, measures interference, and updates noise estimation by modifying the diagonal load in the noise covariance matrix and adjusting LLR scaling based on interference measurements to improve communication with the serving base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic spectrum sharing is implemented between LTE and NR base stations, then spectrum utilization efficiency is improved, but interference from neighboring base stations operating with different RATs causes unequal downlink throughput
Solution Approach 1:
The patent changes the noise estimation parameters by modifying the diagonal load in the noise covariance matrix and adjusting LLR scaling factors based on interference measurements from neighboring RAT base stations. This allows the system to adapt to different interference conditions while maintaining fair throughput distribution across LTE and NR users
Solution Approach 2:
The patent implements a feedback mechanism where the UE measures interference from neighboring base stations, reports this information to the serving base station, and the serving base station uses this feedback to adjust noise estimation and resource allocation. This closed-loop approach ensures equal throughput performance despite spectrum sharing
2Device complexity
If noise estimation is not updated to account for interference from neighboring base stations, then system complexity is reduced, but communication performance deteriorates due to inaccurate noise estimation
Solution Approach 1:
The patent modifies noise estimation parameters (diagonal load and LLR scaling) based on measured interference levels, allowing the system to adapt to changing interference conditions without requiring complete redesign of the noise estimation algorithm
Solution Approach 2:
The patent performs preliminary interference measurements and noise estimation updates before actual data transmission occurs. This allows the system to prepare accurate noise estimates in advance, improving communication performance without adding significant complexity during the transmission process
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may update a noise estimation (e.g., a noise covariance matrix, a log likelihood ratio (LLR) scaling, or both) for communications with a serving base station to account for interference from a neighboring base station operating according to a different radio access technology (RAT). For example, the UE may identify a transmission status of a base station operating according to a first RAT, such as long term evolution (LTE), that shares a radio frequency spectrum with a serving base station operating according to a second RAT, such as new radio (NR). The UE may measure the interference from the LTE base station and may update a noise estimation according to the measured interference. The UE and the serving base station may communicate based on the updated noise estimation.