Dynamic LTE Reference Signal Power Adjustment for 5G Fallback
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Solution Overview
Problem
5G standalone (SA) base stations face challenges in maintaining optimal LTE signal strength for voice calls, leading to call setup failures when users fall back from New Radio (NR) coverage due to non-optimal LTE reference signal settings, resulting in voice over evolved packet system fallback (VoEPSFB) issues.
Innovation Solution
A method and system where the 5G gNodeB dynamically adjusts the 4G LTE reference signal power level based on call setup failures, incrementally increasing the power level when a predefined threshold of failures is exceeded within a predetermined time period to match the 5G NR coverage footprint, thereby preventing voice over 4G fallback failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the LTE reference signal power level is kept at a standard level to maintain network stability, then the network operates reliably, but the LTE coverage area becomes insufficient when users fall back from 5G NR, causing call setup failures
Solution Approach 1:
The patent implements dynamic adjustment of LTE reference signal power levels based on real-time monitoring of call setup failures. The eNodeB receives failure indications from gNodeB and automatically adjusts the power level up or down, transforming the static power configuration into a dynamic adaptive system that responds to actual network conditions
Solution Approach 2:
The system establishes a feedback loop where call setup failure information is transmitted from gNodeB to eNodeB, which then uses this feedback to adjust the LTE reference signal power level. This closed-loop control mechanism enables continuous optimization of coverage area while maintaining call setup success rates
2Area of stationary object
If the LTE reference signal power level is increased to extend coverage area, then more users can successfully fallback for voice calls, but the energy consumption and interference increase
Solution Approach 1:
Instead of maintaining a constantly high power level, the system dynamically adjusts power only when and where needed based on monitored call setup failures. This on-demand adjustment reduces overall energy consumption while maintaining adequate coverage when required
Solution Approach 2:
The patent changes the power level parameter adaptively based on failure rates and coverage requirements. By adjusting the parameter (power level) only when necessary rather than maintaining a fixed high value, the system optimizes the balance between coverage area and energy consumption
Data Source
AI summary
Systems and methods are provided for dynamically adjusting a 4G LTE reference signal power level to match a 5G New Radio (NR) coverage footprint to avoid voice over 4G fallback failures for 5G subscribers. Initially, a subscriber making a voice call while in NR coverage may be directed to fall back to LTE in a process known as voice over evolved packet system fallback (VoEPSFB). If the LTE signal strength is worse due to non-optimal settings of the LTE reference signal, the subscriber experiences call setup failure. After the call setup failure, the UE transitions back to the gNodeB. Since the gNodeB knows the UE attempted to fall back to LTE (as well as how soon the UE transitioned back to the gNodeB), a notification is triggered that instructs the LTE base station to increase its reference signal power level.