RSSI Measurement Acceleration for 3G to 2G Handover
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Solution Overview
Problem
The process of handover from 3G to 2G mobile radio coverage is delayed due to time-consuming RSSI measurements in compressed mode, increasing the risk of call drops when a suitable 2G cell is not found quickly enough.
Innovation Solution
The method involves taking fewer RSSI measurement samples initially and prioritizing the strongest cells for further measurements, allowing for accelerated BSIC identification and reduced measurement time by using compressed mode transmission gaps for GSM carrier RSSI and BSIC identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three RSSI measurement samples are collected for all configured 2G mobile radio cells before handover, then measurement precision is improved, but handover time increases and call drop risk increases
Solution Approach 1:
The patent segments the RSSI measurement process into two phases: a first phase measuring only a subset of 2G neighbor cells (e.g., 6 out of 32), and a second phase measuring the remaining cells. This segmentation allows the UE to quickly obtain sufficient measurement data from the most relevant cells without measuring all configured cells, thereby reducing handover time while maintaining adequate measurement precision for making handover decisions.
Solution Approach 2:
The patent applies partial action by collecting a reduced number of RSSI measurement samples (e.g., one sample instead of three) for the initial subset of cells during the first phase. This partial measurement approach is sufficient to identify the strongest candidate cells for handover, allowing the process to proceed without completing full measurements on all cells, thus reducing the time loss while achieving adequate measurement quality for handover decisions.
2Use of energy by moving object
If compressed mode transmission gaps are used for RSSI measurements, then energy consumption is reduced and 3G connection is maintained, but measurement process becomes more complex and time-consuming
Solution Approach 1:
The patent applies preliminary action by performing a first partial RSSI measurement phase before completing the full measurement process. During this first phase, the UE measures RSSI on a subset of cells using compressed mode transmission gaps, obtaining sufficient data to identify candidate cells. This preliminary measurement reduces the need for extensive subsequent measurements, simplifying the overall process while maintaining energy efficiency through compressed mode usage.
3Reliability
If all configured 2G neighbor cells are measured before handover decision, then reliability of handover decision is improved, but handover speed decreases
Solution Approach 1:
The patent segments the 2G neighbor cell measurement process into two distinct phases: a first phase measuring a limited subset of cells (e.g., 6 cells) to quickly identify candidates, and a second phase measuring the remaining cells. This segmentation enables the UE to make reliable handover decisions based on the strongest candidate identified in the first phase, without being constrained by the need to complete measurements on all configured cells, thus improving handover speed while maintaining decision reliability.
Solution Approach 2:
The patent applies partial action by performing measurements on only a subset of 2G neighbor cells during the critical first phase before handover decision. By measuring fewer cells (e.g., 6 out of 32) with adequate measurement samples, the UE obtains sufficient information to make a reliable handover decision to the strongest candidate, achieving the necessary reliability without the time penalty of measuring all configured cells.
Data Source
AI summary
In various embodiments, a method for measuring Received Signal Strength Indication is provided. The method may include carrying out a first partial Received Signal Strength Indication measurement for a plurality of mobile radio base stations, selecting at least one mobile radio base station out of the plurality of mobile radio base stations based on the result of the first partial Received Signal Strength Indication measurement for a second partial Received Signal Strength Indication measurement, and carrying out the second partial Received Signal Strength Indication measurement for the selected at least one mobile radio base station.