Beam Coherence Interval Metric for 5G mmWave Link Stability
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Solution Overview
Problem
Current 5G mmWave communication systems face inefficiencies in beam management, particularly in handling UE mobility and beam handoffs due to lack of visibility and control over UE receive beams, leading to inadequate handling of angular volume changes and stability.
Innovation Solution
A closed-loop active control system where the UE determines a beam coherence interval metric, measures signal quality, and reports it to the base station, which uses this metric to configure beam measurement resources and reporting, and triggers, enabling more efficient beam management and scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station supports many beams (64+ beams) and the mobile device supports up to 128 beams per phased array antenna panel, then beam coverage and signal quality are improved, but beam management complexity and handoff frequency increase
Solution Approach 1:
The patent implements feedback mechanisms where the mobile device measures beam coherence intervals and reports them to the base station. The base station uses this feedback to dynamically adjust beam management strategies, configure measurement resources, and optimize handoff decisions. This closed-loop feedback system enables intelligent beam management that adapts to channel conditions without requiring manual configuration for each beam scenario.
2Reliability
If frequent beam handoffs are performed under rotational channels (e.g., person turning), then link reliability is maintained, but beam management overhead and switching frequency increase
Solution Approach 1:
The patent introduces dynamic beam management where the base station configures different measurement resource periods and handoff parameters based on the beam coherence interval metric. When channels are stable (large coherence interval), measurement frequency is reduced. When channels change rapidly (small coherence interval, e.g., during rotation), the system dynamically increases measurement frequency and adjusts handoff thresholds. This dynamic adaptation reduces unnecessary beam management overhead during stable periods while maintaining link reliability during rapid changes.
3Measurement precision
If beam measurement and reporting frequency is increased, then beam handoff accuracy is improved, but signaling overhead and processing load increase
Solution Approach 1:
The patent changes the parameter of measurement frequency based on the beam coherence interval metric. Instead of using a fixed measurement frequency for all conditions, the system adjusts the measurement period dynamically: longer periods when beam coherence is high (stable channels), and shorter periods when beam coherence is low (rapidly changing channels). This parameter adaptation ensures accurate beam handoff decisions are made when needed while reducing signaling overhead during stable periods.
4Speed
If the UE autonomously determines beam coherence interval metric and hysteresis value, then beam switching responsiveness is improved, but UE processing complexity increases
Solution Approach 1:
The patent implements self-service mechanisms where the mobile device autonomously measures beam coherence intervals, determines the coherence interval metric, calculates appropriate hysteresis values, and makes beam switching decisions without continuous base station intervention. The UE serves itself by independently managing beam coherence monitoring and handoff execution, which improves responsiveness while the base station retains configuration authority for measurement resources and reporting parameters.
Data Source
AI summary
A user equipment device (UE) determines a beam coherence interval metric, which is a measure of stability of a beam pair over time based on a set of beam coherence intervals measured by the UE. The beam pair comprises a receive beam of the UE and a transmit beam of a base station transmitting to the UE. A beam coherence interval comprises a time duration within which a quality of a signal received on the UE receive beam remains within one of a plurality of signal quality bins. The UE also determines a hysteresis value based on the beam coherence interval metric and uses the hysteresis value to decide to switch from an active receive beam to a different receive beam that has a signal quality higher than the active receive beam by at least the hysteresis value. Alternatively, the base station determines and sends the UE the hysteresis value.