Cellular Downlink Adaptation for Non-Stationary Interference
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Solution Overview
Problem
Conventional 4G and 5G communication systems struggle to maintain consistent block error rate (BLER) due to non-stationary interference from devices like Bluetooth, leading to inconsistent modulation and coding scheme (MCS) selection and reduced throughput.
Innovation Solution
Adapt the target BLER dynamically based on the variance of the SINR offset to mitigate non-stationary interference, using a state machine to switch between different BLER values based on SINR offset thresholds, ensuring consistent BLER convergence and reduced variance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional link adaptation is used with fixed target BLER, then the system operates with simple control logic, but BLER consistency deteriorates under non-stationary interference
Solution Approach 1:
The patent implements dynamic target BLER adjustment based on SINR offset variance. The base station monitors the variance of SINR offsets over time and adapts the target BLER accordingly - increasing it when variance exceeds a threshold to maintain reliability under non-stationary interference, and decreasing it when variance is low to optimize throughput. This transforms the static link adaptation into a dynamic system that responds to changing channel conditions.
Solution Approach 2:
The patent introduces a feedback mechanism where the base station monitors BLER performance and SINR offset variance, then adjusts the target BLER in subsequent transmissions. The gNB receives BLER measurements from the UE and uses this feedback to determine whether to increase or decrease the target BLER, creating a closed-loop control system that maintains BLER consistency under varying interference conditions.
2Reliability
If target BLER is increased to handle interference, then reliability improves, but spectral efficiency deteriorates
Solution Approach 1:
The patent dynamically adjusts the target BLER based on the measured SINR offset variance rather than using a fixed high value. When interference is detected (high variance), the target BLER is increased to maintain reliability. When interference subsides (low variance), the target BLER is decreased to maximize spectral efficiency. This dynamic adjustment ensures that the system only sacrifices throughput when necessary for reliability.
3Productivity
If MCS selection is based on instantaneous SINR, then throughput is maximized in stable conditions, but BLER control fails under non-stationary interference
Solution Approach 1:
The patent introduces the SINR offset variance as an intermediary metric that mediates between instantaneous SINR-based throughput optimization and BLER control reliability. Instead of directly using instantaneous SINR for MCS selection under all conditions, the system first evaluates the variance of SINR offsets. This intermediary assessment determines whether to proceed with aggressive MCS selection (high throughput) or conservative MCS selection (high reliability), effectively decoupling the direct link between instantaneous SINR and MCS selection that fails under non-stationary interference.
Data Source
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AI summary
Example methods and systems for adapting fourth generation (4G) and/or fifth generation (5G) cellular downlink channels in the presence of non-stationary interference are disclosed. An example method, implemented by one or more processors of a cellular base station, includes: receiving, from a user equipment (UE) radio, channel state information (CSI) for a cellular downlink channel between the cellular base station and the UE; determining a signal to interference and noise ratio (SINR) offset based upon the CSI, and a target block error rate (BLER); determining a variance of the SINR offset that represents one or more characteristics of the non-stationary interference; and determining the target BLER based upon the variance of the SINR offset such that the cellular downlink channel adapts to the presence of the non-stationary interference.