Neighbor Relation Table Prioritization for Group Delay Optimization
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Solution Overview
Problem
In LTE wireless networks, group delay variation across subcarriers causes signal distortions, limiting the use of higher order modulation schemes and reducing effective throughput, as base stations struggle to manage subcarrier delays effectively during handovers between sectors.
Innovation Solution
The method involves creating and prioritizing a Neighbor Relation Table (NRT) for base stations based on group delay variation metrics, allowing for the selection of sectors with lower group delay variation for handover operations, thereby optimizing handover decisions and improving signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If base stations use band-pass filters to pass the configured frequency range, then signal quality within the pass band is improved, but group delay variation increases causing signal distortions
Solution Approach 1:
The patent changes the selection criteria for target sectors during handover by incorporating group delay variation metrics. Instead of using traditional metrics alone, the system evaluates and selects sectors with lower group delay variation, thereby reducing signal distortions while maintaining the benefits of band-pass filtering.
2Productivity
If higher order modulation schemes are used, then throughput is improved, but signal distortion from group delay variation limits their effectiveness
Solution Approach 1:
The system performs preliminary evaluation of group delay variation metrics for neighbor sectors before initiating handover. By pre-identifying and prioritizing sectors with lower group delay variation in the Neighbor Relation Table, the system ensures that UEs are handed over to sectors that can support higher order modulation schemes without suffering from excessive signal distortion.
3Speed
If base stations prioritize handover to any available sector, then handover speed is improved, but signal quality deteriorates due to high group delay variation in target sectors
Solution Approach 1:
The Neighbor Relation Table automatically updates itself with group delay variation metrics for neighbor sectors. This self-updating mechanism allows the system to maintain accurate information about sector qualities without requiring manual intervention, enabling fast automated handover decisions that prioritize sectors with lower group delay variation.
4Adaptability or versatility
If the Neighbor Relation Table includes all neighbor sectors, then handover options are improved, but selection complexity increases due to need to evaluate group delay metrics
Solution Approach 1:
The patent applies different evaluation criteria to different sectors in the Neighbor Relation Table by incorporating local group delay variation metrics. Each sector is evaluated and prioritized based on its specific group delay characteristics, allowing the system to maintain comprehensive handover options while simplifying the selection process through automated metric-based prioritization.
Data Source
AI summary
Systems and methods for performing UE handover based on group delay variation include a base station (i) selecting a target neighbor sector from a plurality of neighbor sectors for the handover, where each neighbor sector has a group delay metric, and where the target neighbor sector is selected from the neighbor sectors based at least in part on each neighbor sector's group delay variation and (ii) initiating handover of the UE to the target neighbor sector. Some embodiments include creating a neighbor relations table (NRT) comprising at least some of the neighbor sectors, and prioritizing the NRT based on group delay and/or group delay variation. In some embodiments, selection of the target neighbor sector for the handover is additionally based on neighbor sector handover success rates and Reference Signal Receive Power (RSRP) values for neighbor sectors reported by the UE for which the handover is to be performed.